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chromium / chromium / src / third_party / sqlite / e4d2cf1db15b2e26ab99c61a2a1abc9df83cbc8a / . / src / ext / rbu / sqlite3rbu.c
blob: 4c38e14c9e917f097cd9c6980c6caf77ec96af59 [file] [log] [blame]
/*
** 2014 August 30
**
** The author disclaims copyright to this source code. In place of
** a legal notice, here is a blessing:
**
** May you do good and not evil.
** May you find forgiveness for yourself and forgive others.
** May you share freely, never taking more than you give.
**
*************************************************************************
**
**
** OVERVIEW
**
** The RBU extension requires that the RBU update be packaged as an
** SQLite database. The tables it expects to find are described in
** sqlite3rbu.h. Essentially, for each table xyz in the target database
** that the user wishes to write to, a corresponding data_xyz table is
** created in the RBU database and populated with one row for each row to
** update, insert or delete from the target table.
**
** The update proceeds in three stages:
**
** 1) The database is updated. The modified database pages are written
** to a *-oal file. A *-oal file is just like a *-wal file, except
** that it is named "<database>-oal" instead of "<database>-wal".
** Because regular SQLite clients do not look for file named
** "<database>-oal", they go on using the original database in
** rollback mode while the *-oal file is being generated.
**
** During this stage RBU does not update the database by writing
** directly to the target tables. Instead it creates "imposter"
** tables using the SQLITE_TESTCTRL_IMPOSTER interface that it uses
** to update each b-tree individually. All updates required by each
** b-tree are completed before moving on to the next, and all
** updates are done in sorted key order.
**
** 2) The "<database>-oal" file is moved to the equivalent "<database>-wal"
** location using a call to rename(2). Before doing this the RBU
** module takes an EXCLUSIVE lock on the database file, ensuring
** that there are no other active readers.
**
** Once the EXCLUSIVE lock is released, any other database readers
** detect the new *-wal file and read the database in wal mode. At
** this point they see the new version of the database - including
** the updates made as part of the RBU update.
**
** 3) The new *-wal file is checkpointed. This proceeds in the same way
** as a regular database checkpoint, except that a single frame is
** checkpointed each time sqlite3rbu_step() is called. If the RBU
** handle is closed before the entire *-wal file is checkpointed,
** the checkpoint progress is saved in the RBU database and the
** checkpoint can be resumed by another RBU client at some point in
** the future.
**
** POTENTIAL PROBLEMS
**
** The rename() call might not be portable. And RBU is not currently
** syncing the directory after renaming the file.
**
** When state is saved, any commit to the *-oal file and the commit to
** the RBU update database are not atomic. So if the power fails at the
** wrong moment they might get out of sync. As the main database will be
** committed before the RBU update database this will likely either just
** pass unnoticed, or result in SQLITE_CONSTRAINT errors (due to UNIQUE
** constraint violations).
**
** If some client does modify the target database mid RBU update, or some
** other error occurs, the RBU extension will keep throwing errors. It's
** not really clear how to get out of this state. The system could just
** by delete the RBU update database and *-oal file and have the device
** download the update again and start over.
**
** At present, for an UPDATE, both the new.* and old.* records are
** collected in the rbu_xyz table. And for both UPDATEs and DELETEs all
** fields are collected. This means we're probably writing a lot more
** data to disk when saving the state of an ongoing update to the RBU
** update database than is strictly necessary.
**
*/
#include <assert.h>
#include <string.h>
#include <stdio.h>
#include "sqlite3.h"
#if !defined(SQLITE_CORE) || defined(SQLITE_ENABLE_RBU)
#include "sqlite3rbu.h"
#if defined(_WIN32_WCE)
#include "windows.h"
#endif
/* Maximum number of prepared UPDATE statements held by this module */
#define SQLITE_RBU_UPDATE_CACHESIZE 16
/*
** Swap two objects of type TYPE.
*/
#if !defined(SQLITE_AMALGAMATION)
# define SWAP(TYPE,A,B) {TYPE t=A; A=B; B=t;}
#endif
/*
** The rbu_state table is used to save the state of a partially applied
** update so that it can be resumed later. The table consists of integer
** keys mapped to values as follows:
**
** RBU_STATE_STAGE:
** May be set to integer values 1, 2, 4 or 5. As follows:
** 1: the *-rbu file is currently under construction.
** 2: the *-rbu file has been constructed, but not yet moved
** to the *-wal path.
** 4: the checkpoint is underway.
** 5: the rbu update has been checkpointed.
**
** RBU_STATE_TBL:
** Only valid if STAGE==1. The target database name of the table
** currently being written.
**
** RBU_STATE_IDX:
** Only valid if STAGE==1. The target database name of the index
** currently being written, or NULL if the main table is currently being
** updated.
**
** RBU_STATE_ROW:
** Only valid if STAGE==1. Number of rows already processed for the current
** table/index.
**
** RBU_STATE_PROGRESS:
** Trbul number of sqlite3rbu_step() calls made so far as part of this
** rbu update.
**
** RBU_STATE_CKPT:
** Valid if STAGE==4. The 64-bit checksum associated with the wal-index
** header created by recovering the *-wal file. This is used to detect
** cases when another client appends frames to the *-wal file in the
** middle of an incremental checkpoint (an incremental checkpoint cannot
** be continued if this happens).
**
** RBU_STATE_COOKIE:
** Valid if STAGE==1. The current change-counter cookie value in the
** target db file.
**
** RBU_STATE_OALSZ:
** Valid if STAGE==1. The size in bytes of the *-oal file.
*/
#define RBU_STATE_STAGE 1
#define RBU_STATE_TBL 2
#define RBU_STATE_IDX 3
#define RBU_STATE_ROW 4
#define RBU_STATE_PROGRESS 5
#define RBU_STATE_CKPT 6
#define RBU_STATE_COOKIE 7
#define RBU_STATE_OALSZ 8
#define RBU_STAGE_OAL 1
#define RBU_STAGE_MOVE 2
#define RBU_STAGE_CAPTURE 3
#define RBU_STAGE_CKPT 4
#define RBU_STAGE_DONE 5
#define RBU_CREATE_STATE \
"CREATE TABLE IF NOT EXISTS %s.rbu_state(k INTEGER PRIMARY KEY, v)"
typedef struct RbuFrame RbuFrame;
typedef struct RbuObjIter RbuObjIter;
typedef struct RbuState RbuState;
typedef struct rbu_vfs rbu_vfs;
typedef struct rbu_file rbu_file;
typedef struct RbuUpdateStmt RbuUpdateStmt;
#if !defined(SQLITE_AMALGAMATION)
typedef unsigned int u32;
typedef unsigned char u8;
typedef sqlite3_int64 i64;
#endif
/*
** These values must match the values defined in wal.c for the equivalent
** locks. These are not magic numbers as they are part of the SQLite file
** format.
*/
#define WAL_LOCK_WRITE 0
#define WAL_LOCK_CKPT 1
#define WAL_LOCK_READ0 3
/*
** A structure to store values read from the rbu_state table in memory.
*/
struct RbuState {
int eStage;
char *zTbl;
char *zIdx;
i64 iWalCksum;
int nRow;
i64 nProgress;
u32 iCookie;
i64 iOalSz;
};
struct RbuUpdateStmt {
char *zMask; /* Copy of update mask used with pUpdate */
sqlite3_stmt *pUpdate; /* Last update statement (or NULL) */
RbuUpdateStmt *pNext;
};
/*
** An iterator of this type is used to iterate through all objects in
** the target database that require updating. For each such table, the
** iterator visits, in order:
**
** * the table itself,
** * each index of the table (zero or more points to visit), and
** * a special "cleanup table" state.
**
** abIndexed:
** If the table has no indexes on it, abIndexed is set to NULL. Otherwise,
** it points to an array of flags nTblCol elements in size. The flag is
** set for each column that is either a part of the PK or a part of an
** index. Or clear otherwise.
**
*/
struct RbuObjIter {
sqlite3_stmt *pTblIter; /* Iterate through tables */
sqlite3_stmt *pIdxIter; /* Index iterator */
int nTblCol; /* Size of azTblCol[] array */
char **azTblCol; /* Array of unquoted target column names */
char **azTblType; /* Array of target column types */
int *aiSrcOrder; /* src table col -> target table col */
u8 *abTblPk; /* Array of flags, set on target PK columns */
u8 *abNotNull; /* Array of flags, set on NOT NULL columns */
u8 *abIndexed; /* Array of flags, set on indexed & PK cols */
int eType; /* Table type - an RBU_PK_XXX value */
/* Output variables. zTbl==0 implies EOF. */
int bCleanup; /* True in "cleanup" state */
const char *zTbl; /* Name of target db table */
const char *zDataTbl; /* Name of rbu db table (or null) */
const char *zIdx; /* Name of target db index (or null) */
int iTnum; /* Root page of current object */
int iPkTnum; /* If eType==EXTERNAL, root of PK index */
int bUnique; /* Current index is unique */
/* Statements created by rbuObjIterPrepareAll() */
int nCol; /* Number of columns in current object */
sqlite3_stmt *pSelect; /* Source data */
sqlite3_stmt *pInsert; /* Statement for INSERT operations */
sqlite3_stmt *pDelete; /* Statement for DELETE ops */
sqlite3_stmt *pTmpInsert; /* Insert into rbu_tmp_$zDataTbl */
/* Last UPDATE used (for PK b-tree updates only), or NULL. */
RbuUpdateStmt *pRbuUpdate;
};
/*
** Values for RbuObjIter.eType
**
** 0: Table does not exist (error)
** 1: Table has an implicit rowid.
** 2: Table has an explicit IPK column.
** 3: Table has an external PK index.
** 4: Table is WITHOUT ROWID.
** 5: Table is a virtual table.
*/
#define RBU_PK_NOTABLE 0
#define RBU_PK_NONE 1
#define RBU_PK_IPK 2
#define RBU_PK_EXTERNAL 3
#define RBU_PK_WITHOUT_ROWID 4
#define RBU_PK_VTAB 5
/*
** Within the RBU_STAGE_OAL stage, each call to sqlite3rbu_step() performs
** one of the following operations.
*/
#define RBU_INSERT 1 /* Insert on a main table b-tree */
#define RBU_DELETE 2 /* Delete a row from a main table b-tree */
#define RBU_IDX_DELETE 3 /* Delete a row from an aux. index b-tree */
#define RBU_IDX_INSERT 4 /* Insert on an aux. index b-tree */
#define RBU_UPDATE 5 /* Update a row in a main table b-tree */
/*
** A single step of an incremental checkpoint - frame iWalFrame of the wal
** file should be copied to page iDbPage of the database file.
*/
struct RbuFrame {
u32 iDbPage;
u32 iWalFrame;
};
/*
** RBU handle.
*/
struct sqlite3rbu {
int eStage; /* Value of RBU_STATE_STAGE field */
sqlite3 *dbMain; /* target database handle */
sqlite3 *dbRbu; /* rbu database handle */
char *zTarget; /* Path to target db */
char *zRbu; /* Path to rbu db */
char *zState; /* Path to state db (or NULL if zRbu) */
char zStateDb[5]; /* Db name for state ("stat" or "main") */
int rc; /* Value returned by last rbu_step() call */
char *zErrmsg; /* Error message if rc!=SQLITE_OK */
int nStep; /* Rows processed for current object */
int nProgress; /* Rows processed for all objects */
RbuObjIter objiter; /* Iterator for skipping through tbl/idx */
const char *zVfsName; /* Name of automatically created rbu vfs */
rbu_file *pTargetFd; /* File handle open on target db */
i64 iOalSz;
/* The following state variables are used as part of the incremental
** checkpoint stage (eStage==RBU_STAGE_CKPT). See comments surrounding
** function rbuSetupCheckpoint() for details. */
u32 iMaxFrame; /* Largest iWalFrame value in aFrame[] */
u32 mLock;
int nFrame; /* Entries in aFrame[] array */
int nFrameAlloc; /* Allocated size of aFrame[] array */
RbuFrame *aFrame;
int pgsz;
u8 *aBuf;
i64 iWalCksum;
};
/*
** An rbu VFS is implemented using an instance of this structure.
*/
struct rbu_vfs {
sqlite3_vfs base; /* rbu VFS shim methods */
sqlite3_vfs *pRealVfs; /* Underlying VFS */
sqlite3_mutex *mutex; /* Mutex to protect pMain */
rbu_file *pMain; /* Linked list of main db files */
};
/*
** Each file opened by an rbu VFS is represented by an instance of
** the following structure.
*/
struct rbu_file {
sqlite3_file base; /* sqlite3_file methods */
sqlite3_file *pReal; /* Underlying file handle */
rbu_vfs *pRbuVfs; /* Pointer to the rbu_vfs object */
sqlite3rbu *pRbu; /* Pointer to rbu object (rbu target only) */
int openFlags; /* Flags this file was opened with */
u32 iCookie; /* Cookie value for main db files */
u8 iWriteVer; /* "write-version" value for main db files */
int nShm; /* Number of entries in apShm[] array */
char **apShm; /* Array of mmap'd *-shm regions */
char *zDel; /* Delete this when closing file */
const char *zWal; /* Wal filename for this main db file */
rbu_file *pWalFd; /* Wal file descriptor for this main db */
rbu_file *pMainNext; /* Next MAIN_DB file */
};
/*************************************************************************
** The following three functions, found below:
**
** rbuDeltaGetInt()
** rbuDeltaChecksum()
** rbuDeltaApply()
**
** are lifted from the fossil source code (http://fossil-scm.org). They
** are used to implement the scalar SQL function rbu_fossil_delta().
*/
/*
** Read bytes from *pz and convert them into a positive integer. When
** finished, leave *pz pointing to the first character past the end of
** the integer. The *pLen parameter holds the length of the string
** in *pz and is decremented once for each character in the integer.
*/
static unsigned int rbuDeltaGetInt(const char **pz, int *pLen){
static const signed char zValue[] = {
-1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
-1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
-1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
0, 1, 2, 3, 4, 5, 6, 7, 8, 9, -1, -1, -1, -1, -1, -1,
-1, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24,
25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, -1, -1, -1, -1, 36,
-1, 37, 38, 39, 40, 41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51,
52, 53, 54, 55, 56, 57, 58, 59, 60, 61, 62, -1, -1, -1, 63, -1,
};
unsigned int v = 0;
int c;
unsigned char *z = (unsigned char*)*pz;
unsigned char *zStart = z;
while( (c = zValue[0x7f&*(z++)])>=0 ){
v = (v<<6) + c;
}
z--;
*pLen -= z - zStart;
*pz = (char*)z;
return v;
}
/*
** Compute a 32-bit checksum on the N-byte buffer. Return the result.
*/
static unsigned int rbuDeltaChecksum(const char *zIn, size_t N){
const unsigned char *z = (const unsigned char *)zIn;
unsigned sum0 = 0;
unsigned sum1 = 0;
unsigned sum2 = 0;
unsigned sum3 = 0;
while(N >= 16){
sum0 += ((unsigned)z[0] + z[4] + z[8] + z[12]);
sum1 += ((unsigned)z[1] + z[5] + z[9] + z[13]);
sum2 += ((unsigned)z[2] + z[6] + z[10]+ z[14]);
sum3 += ((unsigned)z[3] + z[7] + z[11]+ z[15]);
z += 16;
N -= 16;
}
while(N >= 4){
sum0 += z[0];
sum1 += z[1];
sum2 += z[2];
sum3 += z[3];
z += 4;
N -= 4;
}
sum3 += (sum2 << 8) + (sum1 << 16) + (sum0 << 24);
switch(N){
case 3: sum3 += (z[2] << 8);
case 2: sum3 += (z[1] << 16);
case 1: sum3 += (z[0] << 24);
default: ;
}
return sum3;
}
/*
** Apply a delta.
**
** The output buffer should be big enough to hold the whole output
** file and a NUL terminator at the end. The delta_output_size()
** routine will determine this size for you.
**
** The delta string should be null-terminated. But the delta string
** may contain embedded NUL characters (if the input and output are
** binary files) so we also have to pass in the length of the delta in
** the lenDelta parameter.
**
** This function returns the size of the output file in bytes (excluding
** the final NUL terminator character). Except, if the delta string is
** malformed or intended for use with a source file other than zSrc,
** then this routine returns -1.
**
** Refer to the delta_create() documentation above for a description
** of the delta file format.
*/
static int rbuDeltaApply(
const char *zSrc, /* The source or pattern file */
int lenSrc, /* Length of the source file */
const char *zDelta, /* Delta to apply to the pattern */
int lenDelta, /* Length of the delta */
char *zOut /* Write the output into this preallocated buffer */
){
unsigned int limit;
unsigned int total = 0;
#ifndef FOSSIL_OMIT_DELTA_CKSUM_TEST
char *zOrigOut = zOut;
#endif
limit = rbuDeltaGetInt(&zDelta, &lenDelta);
if( *zDelta!='\n' ){
/* ERROR: size integer not terminated by "\n" */
return -1;
}
zDelta++; lenDelta--;
while( *zDelta && lenDelta>0 ){
unsigned int cnt, ofst;
cnt = rbuDeltaGetInt(&zDelta, &lenDelta);
switch( zDelta[0] ){
case '@': {
zDelta++; lenDelta--;
ofst = rbuDeltaGetInt(&zDelta, &lenDelta);
if( lenDelta>0 && zDelta[0]!=',' ){
/* ERROR: copy command not terminated by ',' */
return -1;
}
zDelta++; lenDelta--;
total += cnt;
if( total>limit ){
/* ERROR: copy exceeds output file size */
return -1;
}
if( (int)(ofst+cnt) > lenSrc ){
/* ERROR: copy extends past end of input */
return -1;
}
memcpy(zOut, &zSrc[ofst], cnt);
zOut += cnt;
break;
}
case ':': {
zDelta++; lenDelta--;
total += cnt;
if( total>limit ){
/* ERROR: insert command gives an output larger than predicted */
return -1;
}
if( (int)cnt>lenDelta ){
/* ERROR: insert count exceeds size of delta */
return -1;
}
memcpy(zOut, zDelta, cnt);
zOut += cnt;
zDelta += cnt;
lenDelta -= cnt;
break;
}
case ';': {
zDelta++; lenDelta--;
zOut[0] = 0;
#ifndef FOSSIL_OMIT_DELTA_CKSUM_TEST
if( cnt!=rbuDeltaChecksum(zOrigOut, total) ){
/* ERROR: bad checksum */
return -1;
}
#endif
if( total!=limit ){
/* ERROR: generated size does not match predicted size */
return -1;
}
return total;
}
default: {
/* ERROR: unknown delta operator */
return -1;
}
}
}
/* ERROR: unterminated delta */
return -1;
}
static int rbuDeltaOutputSize(const char *zDelta, int lenDelta){
int size;
size = rbuDeltaGetInt(&zDelta, &lenDelta);
if( *zDelta!='\n' ){
/* ERROR: size integer not terminated by "\n" */
return -1;
}
return size;
}
/*
** End of code taken from fossil.
*************************************************************************/
/*
** Implementation of SQL scalar function rbu_fossil_delta().
**
** This function applies a fossil delta patch to a blob. Exactly two
** arguments must be passed to this function. The first is the blob to
** patch and the second the patch to apply. If no error occurs, this
** function returns the patched blob.
*/
static void rbuFossilDeltaFunc(
sqlite3_context *context,
int argc,
sqlite3_value **argv
){
const char *aDelta;
int nDelta;
const char *aOrig;
int nOrig;
int nOut;
int nOut2;
char *aOut;
assert( argc==2 );
nOrig = sqlite3_value_bytes(argv[0]);
aOrig = (const char*)sqlite3_value_blob(argv[0]);
nDelta = sqlite3_value_bytes(argv[1]);
aDelta = (const char*)sqlite3_value_blob(argv[1]);
/* Figure out the size of the output */
nOut = rbuDeltaOutputSize(aDelta, nDelta);
if( nOut<0 ){
sqlite3_result_error(context, "corrupt fossil delta", -1);
return;
}
aOut = sqlite3_malloc(nOut+1);
if( aOut==0 ){
sqlite3_result_error_nomem(context);
}else{
nOut2 = rbuDeltaApply(aOrig, nOrig, aDelta, nDelta, aOut);
if( nOut2!=nOut ){
sqlite3_result_error(context, "corrupt fossil delta", -1);
}else{
sqlite3_result_blob(context, aOut, nOut, sqlite3_free);
}
}
}
/*
** Prepare the SQL statement in buffer zSql against database handle db.
** If successful, set *ppStmt to point to the new statement and return
** SQLITE_OK.
**
** Otherwise, if an error does occur, set *ppStmt to NULL and return
** an SQLite error code. Additionally, set output variable *pzErrmsg to
** point to a buffer containing an error message. It is the responsibility
** of the caller to (eventually) free this buffer using sqlite3_free().
*/
static int prepareAndCollectError(
sqlite3 *db,
sqlite3_stmt **ppStmt,
char **pzErrmsg,
const char *zSql
){
int rc = sqlite3_prepare_v2(db, zSql, -1, ppStmt, 0);
if( rc!=SQLITE_OK ){
*pzErrmsg = sqlite3_mprintf("%s", sqlite3_errmsg(db));
*ppStmt = 0;
}
return rc;
}
/*
** Reset the SQL statement passed as the first argument. Return a copy
** of the value returned by sqlite3_reset().
**
** If an error has occurred, then set *pzErrmsg to point to a buffer
** containing an error message. It is the responsibility of the caller
** to eventually free this buffer using sqlite3_free().
*/
static int resetAndCollectError(sqlite3_stmt *pStmt, char **pzErrmsg){
int rc = sqlite3_reset(pStmt);
if( rc!=SQLITE_OK ){
*pzErrmsg = sqlite3_mprintf("%s", sqlite3_errmsg(sqlite3_db_handle(pStmt)));
}
return rc;
}
/*
** Unless it is NULL, argument zSql points to a buffer allocated using
** sqlite3_malloc containing an SQL statement. This function prepares the SQL
** statement against database db and frees the buffer. If statement
** compilation is successful, *ppStmt is set to point to the new statement
** handle and SQLITE_OK is returned.
**
** Otherwise, if an error occurs, *ppStmt is set to NULL and an error code
** returned. In this case, *pzErrmsg may also be set to point to an error
** message. It is the responsibility of the caller to free this error message
** buffer using sqlite3_free().
**
** If argument zSql is NULL, this function assumes that an OOM has occurred.
** In this case SQLITE_NOMEM is returned and *ppStmt set to NULL.
*/
static int prepareFreeAndCollectError(
sqlite3 *db,
sqlite3_stmt **ppStmt,
char **pzErrmsg,
char *zSql
){
int rc;
assert( *pzErrmsg==0 );
if( zSql==0 ){
rc = SQLITE_NOMEM;
*ppStmt = 0;
}else{
rc = prepareAndCollectError(db, ppStmt, pzErrmsg, zSql);
sqlite3_free(zSql);
}
return rc;
}
/*
** Free the RbuObjIter.azTblCol[] and RbuObjIter.abTblPk[] arrays allocated
** by an earlier call to rbuObjIterCacheTableInfo().
*/
static void rbuObjIterFreeCols(RbuObjIter *pIter){
int i;
for(i=0; i<pIter->nTblCol; i++){
sqlite3_free(pIter->azTblCol[i]);
sqlite3_free(pIter->azTblType[i]);
}
sqlite3_free(pIter->azTblCol);
pIter->azTblCol = 0;
pIter->azTblType = 0;
pIter->aiSrcOrder = 0;
pIter->abTblPk = 0;
pIter->abNotNull = 0;
pIter->nTblCol = 0;
pIter->eType = 0; /* Invalid value */
}
/*
** Finalize all statements and free all allocations that are specific to
** the current object (table/index pair).
*/
static void rbuObjIterClearStatements(RbuObjIter *pIter){
RbuUpdateStmt *pUp;
sqlite3_finalize(pIter->pSelect);
sqlite3_finalize(pIter->pInsert);
sqlite3_finalize(pIter->pDelete);
sqlite3_finalize(pIter->pTmpInsert);
pUp = pIter->pRbuUpdate;
while( pUp ){
RbuUpdateStmt *pTmp = pUp->pNext;
sqlite3_finalize(pUp->pUpdate);
sqlite3_free(pUp);
pUp = pTmp;
}
pIter->pSelect = 0;
pIter->pInsert = 0;
pIter->pDelete = 0;
pIter->pRbuUpdate = 0;
pIter->pTmpInsert = 0;
pIter->nCol = 0;
}
/*
** Clean up any resources allocated as part of the iterator object passed
** as the only argument.
*/
static void rbuObjIterFinalize(RbuObjIter *pIter){
rbuObjIterClearStatements(pIter);
sqlite3_finalize(pIter->pTblIter);
sqlite3_finalize(pIter->pIdxIter);
rbuObjIterFreeCols(pIter);
memset(pIter, 0, sizeof(RbuObjIter));
}
/*
** Advance the iterator to the next position.
**
** If no error occurs, SQLITE_OK is returned and the iterator is left
** pointing to the next entry. Otherwise, an error code and message is
** left in the RBU handle passed as the first argument. A copy of the
** error code is returned.
*/
static int rbuObjIterNext(sqlite3rbu *p, RbuObjIter *pIter){
int rc = p->rc;
if( rc==SQLITE_OK ){
/* Free any SQLite statements used while processing the previous object */
rbuObjIterClearStatements(pIter);
if( pIter->zIdx==0 ){
rc = sqlite3_exec(p->dbMain,
"DROP TRIGGER IF EXISTS temp.rbu_insert_tr;"
"DROP TRIGGER IF EXISTS temp.rbu_update1_tr;"
"DROP TRIGGER IF EXISTS temp.rbu_update2_tr;"
"DROP TRIGGER IF EXISTS temp.rbu_delete_tr;"
, 0, 0, &p->zErrmsg
);
}
if( rc==SQLITE_OK ){
if( pIter->bCleanup ){
rbuObjIterFreeCols(pIter);
pIter->bCleanup = 0;
rc = sqlite3_step(pIter->pTblIter);
if( rc!=SQLITE_ROW ){
rc = resetAndCollectError(pIter->pTblIter, &p->zErrmsg);
pIter->zTbl = 0;
}else{
pIter->zTbl = (const char*)sqlite3_column_text(pIter->pTblIter, 0);
pIter->zDataTbl = (const char*)sqlite3_column_text(pIter->pTblIter,1);
rc = (pIter->zDataTbl && pIter->zTbl) ? SQLITE_OK : SQLITE_NOMEM;
}
}else{
if( pIter->zIdx==0 ){
sqlite3_stmt *pIdx = pIter->pIdxIter;
rc = sqlite3_bind_text(pIdx, 1, pIter->zTbl, -1, SQLITE_STATIC);
}
if( rc==SQLITE_OK ){
rc = sqlite3_step(pIter->pIdxIter);
if( rc!=SQLITE_ROW ){
rc = resetAndCollectError(pIter->pIdxIter, &p->zErrmsg);
pIter->bCleanup = 1;
pIter->zIdx = 0;
}else{
pIter->zIdx = (const char*)sqlite3_column_text(pIter->pIdxIter, 0);
pIter->iTnum = sqlite3_column_int(pIter->pIdxIter, 1);
pIter->bUnique = sqlite3_column_int(pIter->pIdxIter, 2);
rc = pIter->zIdx ? SQLITE_OK : SQLITE_NOMEM;
}
}
}
}
}
if( rc!=SQLITE_OK ){
rbuObjIterFinalize(pIter);
p->rc = rc;
}
return rc;
}
/*
** The implementation of the rbu_target_name() SQL function. This function
** accepts one argument - the name of a table in the RBU database. If the
** table name matches the pattern:
**
** data[0-9]_<name>
**
** where <name> is any sequence of 1 or more characters, <name> is returned.
** Otherwise, if the only argument does not match the above pattern, an SQL
** NULL is returned.
**
** "data_t1" -> "t1"
** "data0123_t2" -> "t2"
** "dataAB_t3" -> NULL
*/
static void rbuTargetNameFunc(
sqlite3_context *context,
int argc,
sqlite3_value **argv
){
const char *zIn;
assert( argc==1 );
zIn = (const char*)sqlite3_value_text(argv[0]);
if( zIn && strlen(zIn)>4 && memcmp("data", zIn, 4)==0 ){
int i;
for(i=4; zIn[i]>='0' && zIn[i]<='9'; i++);
if( zIn[i]=='_' && zIn[i+1] ){
sqlite3_result_text(context, &zIn[i+1], -1, SQLITE_STATIC);
}
}
}
/*
** Initialize the iterator structure passed as the second argument.
**
** If no error occurs, SQLITE_OK is returned and the iterator is left
** pointing to the first entry. Otherwise, an error code and message is
** left in the RBU handle passed as the first argument. A copy of the
** error code is returned.
*/
static int rbuObjIterFirst(sqlite3rbu *p, RbuObjIter *pIter){
int rc;
memset(pIter, 0, sizeof(RbuObjIter));
rc = prepareAndCollectError(p->dbRbu, &pIter->pTblIter, &p->zErrmsg,
"SELECT rbu_target_name(name) AS target, name FROM sqlite_master "
"WHERE type IN ('table', 'view') AND target IS NOT NULL "
"ORDER BY name"
);
if( rc==SQLITE_OK ){
rc = prepareAndCollectError(p->dbMain, &pIter->pIdxIter, &p->zErrmsg,
"SELECT name, rootpage, sql IS NULL OR substr(8, 6)=='UNIQUE' "
" FROM main.sqlite_master "
" WHERE type='index' AND tbl_name = ?"
);
}
pIter->bCleanup = 1;
p->rc = rc;
return rbuObjIterNext(p, pIter);
}
/*
** This is a wrapper around "sqlite3_mprintf(zFmt, ...)". If an OOM occurs,
** an error code is stored in the RBU handle passed as the first argument.
**
** If an error has already occurred (p->rc is already set to something other
** than SQLITE_OK), then this function returns NULL without modifying the
** stored error code. In this case it still calls sqlite3_free() on any
** printf() parameters associated with %z conversions.
*/
static char *rbuMPrintf(sqlite3rbu *p, const char *zFmt, ...){
char *zSql = 0;
va_list ap;
va_start(ap, zFmt);
zSql = sqlite3_vmprintf(zFmt, ap);
if( p->rc==SQLITE_OK ){
if( zSql==0 ) p->rc = SQLITE_NOMEM;
}else{
sqlite3_free(zSql);
zSql = 0;
}
va_end(ap);
return zSql;
}
/*
** Argument zFmt is a sqlite3_mprintf() style format string. The trailing
** arguments are the usual subsitution values. This function performs
** the printf() style substitutions and executes the result as an SQL
** statement on the RBU handles database.
**
** If an error occurs, an error code and error message is stored in the
** RBU handle. If an error has already occurred when this function is
** called, it is a no-op.
*/
static int rbuMPrintfExec(sqlite3rbu *p, sqlite3 *db, const char *zFmt, ...){
va_list ap;
char *zSql;
va_start(ap, zFmt);
zSql = sqlite3_vmprintf(zFmt, ap);
if( p->rc==SQLITE_OK ){
if( zSql==0 ){
p->rc = SQLITE_NOMEM;
}else{
p->rc = sqlite3_exec(db, zSql, 0, 0, &p->zErrmsg);
}
}
sqlite3_free(zSql);
va_end(ap);
return p->rc;
}
/*
** Attempt to allocate and return a pointer to a zeroed block of nByte
** bytes.
**
** If an error (i.e. an OOM condition) occurs, return NULL and leave an
** error code in the rbu handle passed as the first argument. Or, if an
** error has already occurred when this function is called, return NULL
** immediately without attempting the allocation or modifying the stored
** error code.
*/
static void *rbuMalloc(sqlite3rbu *p, int nByte){
void *pRet = 0;
if( p->rc==SQLITE_OK ){
assert( nByte>0 );
pRet = sqlite3_malloc(nByte);
if( pRet==0 ){
p->rc = SQLITE_NOMEM;
}else{
memset(pRet, 0, nByte);
}
}
return pRet;
}
/*
** Allocate and zero the pIter->azTblCol[] and abTblPk[] arrays so that
** there is room for at least nCol elements. If an OOM occurs, store an
** error code in the RBU handle passed as the first argument.
*/
static void rbuAllocateIterArrays(sqlite3rbu *p, RbuObjIter *pIter, int nCol){
int nByte = (2*sizeof(char*) + sizeof(int) + 3*sizeof(u8)) * nCol;
char **azNew;
azNew = (char**)rbuMalloc(p, nByte);
if( azNew ){
pIter->azTblCol = azNew;
pIter->azTblType = &azNew[nCol];
pIter->aiSrcOrder = (int*)&pIter->azTblType[nCol];
pIter->abTblPk = (u8*)&pIter->aiSrcOrder[nCol];
pIter->abNotNull = (u8*)&pIter->abTblPk[nCol];
pIter->abIndexed = (u8*)&pIter->abNotNull[nCol];
}
}
/*
** The first argument must be a nul-terminated string. This function
** returns a copy of the string in memory obtained from sqlite3_malloc().
** It is the responsibility of the caller to eventually free this memory
** using sqlite3_free().
**
** If an OOM condition is encountered when attempting to allocate memory,
** output variable (*pRc) is set to SQLITE_NOMEM before returning. Otherwise,
** if the allocation succeeds, (*pRc) is left unchanged.
*/
static char *rbuStrndup(const char *zStr, int *pRc){
char *zRet = 0;
assert( *pRc==SQLITE_OK );
if( zStr ){
int nCopy = strlen(zStr) + 1;
zRet = (char*)sqlite3_malloc(nCopy);
if( zRet ){
memcpy(zRet, zStr, nCopy);
}else{
*pRc = SQLITE_NOMEM;
}
}
return zRet;
}
/*
** Finalize the statement passed as the second argument.
**
** If the sqlite3_finalize() call indicates that an error occurs, and the
** rbu handle error code is not already set, set the error code and error
** message accordingly.
*/
static void rbuFinalize(sqlite3rbu *p, sqlite3_stmt *pStmt){
sqlite3 *db = sqlite3_db_handle(pStmt);
int rc = sqlite3_finalize(pStmt);
if( p->rc==SQLITE_OK && rc!=SQLITE_OK ){
p->rc = rc;
p->zErrmsg = sqlite3_mprintf("%s", sqlite3_errmsg(db));
}
}
/* Determine the type of a table.
**
** peType is of type (int*), a pointer to an output parameter of type
** (int). This call sets the output parameter as follows, depending
** on the type of the table specified by parameters dbName and zTbl.
**
** RBU_PK_NOTABLE: No such table.
** RBU_PK_NONE: Table has an implicit rowid.
** RBU_PK_IPK: Table has an explicit IPK column.
** RBU_PK_EXTERNAL: Table has an external PK index.
** RBU_PK_WITHOUT_ROWID: Table is WITHOUT ROWID.
** RBU_PK_VTAB: Table is a virtual table.
**
** Argument *piPk is also of type (int*), and also points to an output
** parameter. Unless the table has an external primary key index
** (i.e. unless *peType is set to 3), then *piPk is set to zero. Or,
** if the table does have an external primary key index, then *piPk
** is set to the root page number of the primary key index before
** returning.
**
** ALGORITHM:
**
** if( no entry exists in sqlite_master ){
** return RBU_PK_NOTABLE
** }else if( sql for the entry starts with "CREATE VIRTUAL" ){
** return RBU_PK_VTAB
** }else if( "PRAGMA index_list()" for the table contains a "pk" index ){
** if( the index that is the pk exists in sqlite_master ){
** *piPK = rootpage of that index.
** return RBU_PK_EXTERNAL
** }else{
** return RBU_PK_WITHOUT_ROWID
** }
** }else if( "PRAGMA table_info()" lists one or more "pk" columns ){
** return RBU_PK_IPK
** }else{
** return RBU_PK_NONE
** }
*/
static void rbuTableType(
sqlite3rbu *p,
const char *zTab,
int *peType,
int *piTnum,
int *piPk
){
/*
** 0) SELECT count(*) FROM sqlite_master where name=%Q AND IsVirtual(%Q)
** 1) PRAGMA index_list = ?
** 2) SELECT count(*) FROM sqlite_master where name=%Q
** 3) PRAGMA table_info = ?
*/
sqlite3_stmt *aStmt[4] = {0, 0, 0, 0};
*peType = RBU_PK_NOTABLE;
*piPk = 0;
assert( p->rc==SQLITE_OK );
p->rc = prepareFreeAndCollectError(p->dbMain, &aStmt[0], &p->zErrmsg,
sqlite3_mprintf(
"SELECT (sql LIKE 'create virtual%%'), rootpage"
" FROM sqlite_master"
" WHERE name=%Q", zTab
));
if( p->rc!=SQLITE_OK || sqlite3_step(aStmt[0])!=SQLITE_ROW ){
/* Either an error, or no such table. */
goto rbuTableType_end;
}
if( sqlite3_column_int(aStmt[0], 0) ){
*peType = RBU_PK_VTAB; /* virtual table */
goto rbuTableType_end;
}
*piTnum = sqlite3_column_int(aStmt[0], 1);
p->rc = prepareFreeAndCollectError(p->dbMain, &aStmt[1], &p->zErrmsg,
sqlite3_mprintf("PRAGMA index_list=%Q",zTab)
);
if( p->rc ) goto rbuTableType_end;
while( sqlite3_step(aStmt[1])==SQLITE_ROW ){
const u8 *zOrig = sqlite3_column_text(aStmt[1], 3);
const u8 *zIdx = sqlite3_column_text(aStmt[1], 1);
if( zOrig && zIdx && zOrig[0]=='p' ){
p->rc = prepareFreeAndCollectError(p->dbMain, &aStmt[2], &p->zErrmsg,
sqlite3_mprintf(
"SELECT rootpage FROM sqlite_master WHERE name = %Q", zIdx
));
if( p->rc==SQLITE_OK ){
if( sqlite3_step(aStmt[2])==SQLITE_ROW ){
*piPk = sqlite3_column_int(aStmt[2], 0);
*peType = RBU_PK_EXTERNAL;
}else{
*peType = RBU_PK_WITHOUT_ROWID;
}
}
goto rbuTableType_end;
}
}
p->rc = prepareFreeAndCollectError(p->dbMain, &aStmt[3], &p->zErrmsg,
sqlite3_mprintf("PRAGMA table_info=%Q",zTab)
);
if( p->rc==SQLITE_OK ){
while( sqlite3_step(aStmt[3])==SQLITE_ROW ){
if( sqlite3_column_int(aStmt[3],5)>0 ){
*peType = RBU_PK_IPK; /* explicit IPK column */
goto rbuTableType_end;
}
}
*peType = RBU_PK_NONE;
}
rbuTableType_end: {
unsigned int i;
for(i=0; i<sizeof(aStmt)/sizeof(aStmt[0]); i++){
rbuFinalize(p, aStmt[i]);
}
}
}
/*
** This is a helper function for rbuObjIterCacheTableInfo(). It populates
** the pIter->abIndexed[] array.
*/
static void rbuObjIterCacheIndexedCols(sqlite3rbu *p, RbuObjIter *pIter){
sqlite3_stmt *pList = 0;
int bIndex = 0;
if( p->rc==SQLITE_OK ){
memcpy(pIter->abIndexed, pIter->abTblPk, sizeof(u8)*pIter->nTblCol);
p->rc = prepareFreeAndCollectError(p->dbMain, &pList, &p->zErrmsg,
sqlite3_mprintf("PRAGMA main.index_list = %Q", pIter->zTbl)
);
}
while( p->rc==SQLITE_OK && SQLITE_ROW==sqlite3_step(pList) ){
const char *zIdx = (const char*)sqlite3_column_text(pList, 1);
sqlite3_stmt *pXInfo = 0;
if( zIdx==0 ) break;
p->rc = prepareFreeAndCollectError(p->dbMain, &pXInfo, &p->zErrmsg,
sqlite3_mprintf("PRAGMA main.index_xinfo = %Q", zIdx)
);
while( p->rc==SQLITE_OK && SQLITE_ROW==sqlite3_step(pXInfo) ){
int iCid = sqlite3_column_int(pXInfo, 1);
if( iCid>=0 ) pIter->abIndexed[iCid] = 1;
}
rbuFinalize(p, pXInfo);
bIndex = 1;
}
rbuFinalize(p, pList);
if( bIndex==0 ) pIter->abIndexed = 0;
}
/*
** If they are not already populated, populate the pIter->azTblCol[],
** pIter->abTblPk[], pIter->nTblCol and pIter->bRowid variables according to
** the table (not index) that the iterator currently points to.
**
** Return SQLITE_OK if successful, or an SQLite error code otherwise. If
** an error does occur, an error code and error message are also left in
** the RBU handle.
*/
static int rbuObjIterCacheTableInfo(sqlite3rbu *p, RbuObjIter *pIter){
if( pIter->azTblCol==0 ){
sqlite3_stmt *pStmt = 0;
int nCol = 0;
int i; /* for() loop iterator variable */
int bRbuRowid = 0; /* If input table has column "rbu_rowid" */
int iOrder = 0;
int iTnum = 0;
/* Figure out the type of table this step will deal with. */
assert( pIter->eType==0 );
rbuTableType(p, pIter->zTbl, &pIter->eType, &iTnum, &pIter->iPkTnum);
if( p->rc==SQLITE_OK && pIter->eType==RBU_PK_NOTABLE ){
p->rc = SQLITE_ERROR;
p->zErrmsg = sqlite3_mprintf("no such table: %s", pIter->zTbl);
}
if( p->rc ) return p->rc;
if( pIter->zIdx==0 ) pIter->iTnum = iTnum;
assert( pIter->eType==RBU_PK_NONE || pIter->eType==RBU_PK_IPK
|| pIter->eType==RBU_PK_EXTERNAL || pIter->eType==RBU_PK_WITHOUT_ROWID
|| pIter->eType==RBU_PK_VTAB
);
/* Populate the azTblCol[] and nTblCol variables based on the columns
** of the input table. Ignore any input table columns that begin with
** "rbu_". */
p->rc = prepareFreeAndCollectError(p->dbRbu, &pStmt, &p->zErrmsg,
sqlite3_mprintf("SELECT * FROM '%q'", pIter->zDataTbl)
);
if( p->rc==SQLITE_OK ){
nCol = sqlite3_column_count(pStmt);
rbuAllocateIterArrays(p, pIter, nCol);
}
for(i=0; p->rc==SQLITE_OK && i<nCol; i++){
const char *zName = (const char*)sqlite3_column_name(pStmt, i);
if( sqlite3_strnicmp("rbu_", zName, 4) ){
char *zCopy = rbuStrndup(zName, &p->rc);
pIter->aiSrcOrder[pIter->nTblCol] = pIter->nTblCol;
pIter->azTblCol[pIter->nTblCol++] = zCopy;
}
else if( 0==sqlite3_stricmp("rbu_rowid", zName) ){
bRbuRowid = 1;
}
}
sqlite3_finalize(pStmt);
pStmt = 0;
if( p->rc==SQLITE_OK
&& bRbuRowid!=(pIter->eType==RBU_PK_VTAB || pIter->eType==RBU_PK_NONE)
){
p->rc = SQLITE_ERROR;
p->zErrmsg = sqlite3_mprintf(
"table %q %s rbu_rowid column", pIter->zDataTbl,
(bRbuRowid ? "may not have" : "requires")
);
}
/* Check that all non-HIDDEN columns in the destination table are also
** present in the input table. Populate the abTblPk[], azTblType[] and
** aiTblOrder[] arrays at the same time. */
if( p->rc==SQLITE_OK ){
p->rc = prepareFreeAndCollectError(p->dbMain, &pStmt, &p->zErrmsg,
sqlite3_mprintf("PRAGMA table_info(%Q)", pIter->zTbl)
);
}
while( p->rc==SQLITE_OK && SQLITE_ROW==sqlite3_step(pStmt) ){
const char *zName = (const char*)sqlite3_column_text(pStmt, 1);
if( zName==0 ) break; /* An OOM - finalize() below returns S_NOMEM */
for(i=iOrder; i<pIter->nTblCol; i++){
if( 0==strcmp(zName, pIter->azTblCol[i]) ) break;
}
if( i==pIter->nTblCol ){
p->rc = SQLITE_ERROR;
p->zErrmsg = sqlite3_mprintf("column missing from %q: %s",
pIter->zDataTbl, zName
);
}else{
int iPk = sqlite3_column_int(pStmt, 5);
int bNotNull = sqlite3_column_int(pStmt, 3);
const char *zType = (const char*)sqlite3_column_text(pStmt, 2);
if( i!=iOrder ){
SWAP(int, pIter->aiSrcOrder[i], pIter->aiSrcOrder[iOrder]);
SWAP(char*, pIter->azTblCol[i], pIter->azTblCol[iOrder]);
}
pIter->azTblType[iOrder] = rbuStrndup(zType, &p->rc);
pIter->abTblPk[iOrder] = (iPk!=0);
pIter->abNotNull[iOrder] = (u8)bNotNull || (iPk!=0);
iOrder++;
}
}
rbuFinalize(p, pStmt);
rbuObjIterCacheIndexedCols(p, pIter);
assert( pIter->eType!=RBU_PK_VTAB || pIter->abIndexed==0 );
}
return p->rc;
}
/*
** This function constructs and returns a pointer to a nul-terminated
** string containing some SQL clause or list based on one or more of the
** column names currently stored in the pIter->azTblCol[] array.
*/
static char *rbuObjIterGetCollist(
sqlite3rbu *p, /* RBU object */
RbuObjIter *pIter /* Object iterator for column names */
){
char *zList = 0;
const char *zSep = "";
int i;
for(i=0; i<pIter->nTblCol; i++){
const char *z = pIter->azTblCol[i];
zList = rbuMPrintf(p, "%z%s\"%w\"", zList, zSep, z);
zSep = ", ";
}
return zList;
}
/*
** This function is used to create a SELECT list (the list of SQL
** expressions that follows a SELECT keyword) for a SELECT statement
** used to read from an data_xxx or rbu_tmp_xxx table while updating the
** index object currently indicated by the iterator object passed as the
** second argument. A "PRAGMA index_xinfo = <idxname>" statement is used
** to obtain the required information.
**
** If the index is of the following form:
**
** CREATE INDEX i1 ON t1(c, b COLLATE nocase);
**
** and "t1" is a table with an explicit INTEGER PRIMARY KEY column
** "ipk", the returned string is:
**
** "`c` COLLATE 'BINARY', `b` COLLATE 'NOCASE', `ipk` COLLATE 'BINARY'"
**
** As well as the returned string, three other malloc'd strings are
** returned via output parameters. As follows:
**
** pzImposterCols: ...
** pzImposterPk: ...
** pzWhere: ...
*/
static char *rbuObjIterGetIndexCols(
sqlite3rbu *p, /* RBU object */
RbuObjIter *pIter, /* Object iterator for column names */
char **pzImposterCols, /* OUT: Columns for imposter table */
char **pzImposterPk, /* OUT: Imposter PK clause */
char **pzWhere, /* OUT: WHERE clause */
int *pnBind /* OUT: Trbul number of columns */
){
int rc = p->rc; /* Error code */
int rc2; /* sqlite3_finalize() return code */
char *zRet = 0; /* String to return */
char *zImpCols = 0; /* String to return via *pzImposterCols */
char *zImpPK = 0; /* String to return via *pzImposterPK */
char *zWhere = 0; /* String to return via *pzWhere */
int nBind = 0; /* Value to return via *pnBind */
const char *zCom = ""; /* Set to ", " later on */
const char *zAnd = ""; /* Set to " AND " later on */
sqlite3_stmt *pXInfo = 0; /* PRAGMA index_xinfo = ? */
if( rc==SQLITE_OK ){
assert( p->zErrmsg==0 );
rc = prepareFreeAndCollectError(p->dbMain, &pXInfo, &p->zErrmsg,
sqlite3_mprintf("PRAGMA main.index_xinfo = %Q", pIter->zIdx)
);
}
while( rc==SQLITE_OK && SQLITE_ROW==sqlite3_step(pXInfo) ){
int iCid = sqlite3_column_int(pXInfo, 1);
int bDesc = sqlite3_column_int(pXInfo, 3);
const char *zCollate = (const char*)sqlite3_column_text(pXInfo, 4);
const char *zCol;
const char *zType;
if( iCid<0 ){
/* An integer primary key. If the table has an explicit IPK, use
** its name. Otherwise, use "rbu_rowid". */
if( pIter->eType==RBU_PK_IPK ){
int i;
for(i=0; pIter->abTblPk[i]==0; i++);
assert( i<pIter->nTblCol );
zCol = pIter->azTblCol[i];
}else{
zCol = "rbu_rowid";
}
zType = "INTEGER";
}else{
zCol = pIter->azTblCol[iCid];
zType = pIter->azTblType[iCid];
}
zRet = sqlite3_mprintf("%z%s\"%w\" COLLATE %Q", zRet, zCom, zCol, zCollate);
if( pIter->bUnique==0 || sqlite3_column_int(pXInfo, 5) ){
const char *zOrder = (bDesc ? " DESC" : "");
zImpPK = sqlite3_mprintf("%z%s\"rbu_imp_%d%w\"%s",
zImpPK, zCom, nBind, zCol, zOrder
);
}
zImpCols = sqlite3_mprintf("%z%s\"rbu_imp_%d%w\" %s COLLATE %Q",
zImpCols, zCom, nBind, zCol, zType, zCollate
);
zWhere = sqlite3_mprintf(
"%z%s\"rbu_imp_%d%w\" IS ?", zWhere, zAnd, nBind, zCol
);
if( zRet==0 || zImpPK==0 || zImpCols==0 || zWhere==0 ) rc = SQLITE_NOMEM;
zCom = ", ";
zAnd = " AND ";
nBind++;
}
rc2 = sqlite3_finalize(pXInfo);
if( rc==SQLITE_OK ) rc = rc2;
if( rc!=SQLITE_OK ){
sqlite3_free(zRet);
sqlite3_free(zImpCols);
sqlite3_free(zImpPK);
sqlite3_free(zWhere);
zRet = 0;
zImpCols = 0;
zImpPK = 0;
zWhere = 0;
p->rc = rc;
}
*pzImposterCols = zImpCols;
*pzImposterPk = zImpPK;
*pzWhere = zWhere;
*pnBind = nBind;
return zRet;
}
/*
** Assuming the current table columns are "a", "b" and "c", and the zObj
** paramter is passed "old", return a string of the form:
**
** "old.a, old.b, old.b"
**
** With the column names escaped.
**
** For tables with implicit rowids - RBU_PK_EXTERNAL and RBU_PK_NONE, append
** the text ", old._rowid_" to the returned value.
*/
static char *rbuObjIterGetOldlist(
sqlite3rbu *p,
RbuObjIter *pIter,
const char *zObj
){
char *zList = 0;
if( p->rc==SQLITE_OK && pIter->abIndexed ){
const char *zS = "";
int i;
for(i=0; i<pIter->nTblCol; i++){
if( pIter->abIndexed[i] ){
const char *zCol = pIter->azTblCol[i];
zList = sqlite3_mprintf("%z%s%s.\"%w\"", zList, zS, zObj, zCol);
}else{
zList = sqlite3_mprintf("%z%sNULL", zList, zS);
}
zS = ", ";
if( zList==0 ){
p->rc = SQLITE_NOMEM;
break;
}
}
/* For a table with implicit rowids, append "old._rowid_" to the list. */
if( pIter->eType==RBU_PK_EXTERNAL || pIter->eType==RBU_PK_NONE ){
zList = rbuMPrintf(p, "%z, %s._rowid_", zList, zObj);
}
}
return zList;
}
/*
** Return an expression that can be used in a WHERE clause to match the
** primary key of the current table. For example, if the table is:
**
** CREATE TABLE t1(a, b, c, PRIMARY KEY(b, c));
**
** Return the string:
**
** "b = ?1 AND c = ?2"
*/
static char *rbuObjIterGetWhere(
sqlite3rbu *p,
RbuObjIter *pIter
){
char *zList = 0;
if( pIter->eType==RBU_PK_VTAB || pIter->eType==RBU_PK_NONE ){
zList = rbuMPrintf(p, "_rowid_ = ?%d", pIter->nTblCol+1);
}else if( pIter->eType==RBU_PK_EXTERNAL ){
const char *zSep = "";
int i;
for(i=0; i<pIter->nTblCol; i++){
if( pIter->abTblPk[i] ){
zList = rbuMPrintf(p, "%z%sc%d=?%d", zList, zSep, i, i+1);
zSep = " AND ";
}
}
zList = rbuMPrintf(p,
"_rowid_ = (SELECT id FROM rbu_imposter2 WHERE %z)", zList
);
}else{
const char *zSep = "";
int i;
for(i=0; i<pIter->nTblCol; i++){
if( pIter->abTblPk[i] ){
const char *zCol = pIter->azTblCol[i];
zList = rbuMPrintf(p, "%z%s\"%w\"=?%d", zList, zSep, zCol, i+1);
zSep = " AND ";
}
}
}
return zList;
}
/*
** The SELECT statement iterating through the keys for the current object
** (p->objiter.pSelect) currently points to a valid row. However, there
** is something wrong with the rbu_control value in the rbu_control value
** stored in the (p->nCol+1)'th column. Set the error code and error message
** of the RBU handle to something reflecting this.
*/
static void rbuBadControlError(sqlite3rbu *p){
p->rc = SQLITE_ERROR;
p->zErrmsg = sqlite3_mprintf("invalid rbu_control value");
}
/*
** Return a nul-terminated string containing the comma separated list of
** assignments that should be included following the "SET" keyword of
** an UPDATE statement used to update the table object that the iterator
** passed as the second argument currently points to if the rbu_control
** column of the data_xxx table entry is set to zMask.
**
** The memory for the returned string is obtained from sqlite3_malloc().
** It is the responsibility of the caller to eventually free it using
** sqlite3_free().
**
** If an OOM error is encountered when allocating space for the new
** string, an error code is left in the rbu handle passed as the first
** argument and NULL is returned. Or, if an error has already occurred
** when this function is called, NULL is returned immediately, without
** attempting the allocation or modifying the stored error code.
*/
static char *rbuObjIterGetSetlist(
sqlite3rbu *p,
RbuObjIter *pIter,
const char *zMask
){
char *zList = 0;
if( p->rc==SQLITE_OK ){
int i;
if( (int)strlen(zMask)!=pIter->nTblCol ){
rbuBadControlError(p);
}else{
const char *zSep = "";
for(i=0; i<pIter->nTblCol; i++){
char c = zMask[pIter->aiSrcOrder[i]];
if( c=='x' ){
zList = rbuMPrintf(p, "%z%s\"%w\"=?%d",
zList, zSep, pIter->azTblCol[i], i+1
);
zSep = ", ";
}
else if( c=='d' ){
zList = rbuMPrintf(p, "%z%s\"%w\"=rbu_delta(\"%w\", ?%d)",
zList, zSep, pIter->azTblCol[i], pIter->azTblCol[i], i+1
);
zSep = ", ";
}
else if( c=='f' ){
zList = rbuMPrintf(p, "%z%s\"%w\"=rbu_fossil_delta(\"%w\", ?%d)",
zList, zSep, pIter->azTblCol[i], pIter->azTblCol[i], i+1
);
zSep = ", ";
}
}
}
}
return zList;
}
/*
** Return a nul-terminated string consisting of nByte comma separated
** "?" expressions. For example, if nByte is 3, return a pointer to
** a buffer containing the string "?,?,?".
**
** The memory for the returned string is obtained from sqlite3_malloc().
** It is the responsibility of the caller to eventually free it using
** sqlite3_free().
**
** If an OOM error is encountered when allocating space for the new
** string, an error code is left in the rbu handle passed as the first
** argument and NULL is returned. Or, if an error has already occurred
** when this function is called, NULL is returned immediately, without
** attempting the allocation or modifying the stored error code.
*/
static char *rbuObjIterGetBindlist(sqlite3rbu *p, int nBind){
char *zRet = 0;
int nByte = nBind*2 + 1;
zRet = (char*)rbuMalloc(p, nByte);
if( zRet ){
int i;
for(i=0; i<nBind; i++){
zRet[i*2] = '?';
zRet[i*2+1] = (i+1==nBind) ? '\0' : ',';
}
}
return zRet;
}
/*
** The iterator currently points to a table (not index) of type
** RBU_PK_WITHOUT_ROWID. This function creates the PRIMARY KEY
** declaration for the corresponding imposter table. For example,
** if the iterator points to a table created as:
**
** CREATE TABLE t1(a, b, c, PRIMARY KEY(b, a DESC)) WITHOUT ROWID
**
** this function returns:
**
** PRIMARY KEY("b", "a" DESC)
*/
static char *rbuWithoutRowidPK(sqlite3rbu *p, RbuObjIter *pIter){
char *z = 0;
assert( pIter->zIdx==0 );
if( p->rc==SQLITE_OK ){
const char *zSep = "PRIMARY KEY(";
sqlite3_stmt *pXList = 0; /* PRAGMA index_list = (pIter->zTbl) */
sqlite3_stmt *pXInfo = 0; /* PRAGMA index_xinfo = <pk-index> */
p->rc = prepareFreeAndCollectError(p->dbMain, &pXList, &p->zErrmsg,
sqlite3_mprintf("PRAGMA main.index_list = %Q", pIter->zTbl)
);
while( p->rc==SQLITE_OK && SQLITE_ROW==sqlite3_step(pXList) ){
const char *zOrig = (const char*)sqlite3_column_text(pXList,3);
if( zOrig && strcmp(zOrig, "pk")==0 ){
const char *zIdx = (const char*)sqlite3_column_text(pXList,1);
if( zIdx ){
p->rc = prepareFreeAndCollectError(p->dbMain, &pXInfo, &p->zErrmsg,
sqlite3_mprintf("PRAGMA main.index_xinfo = %Q", zIdx)
);
}
break;
}
}
rbuFinalize(p, pXList);
while( p->rc==SQLITE_OK && SQLITE_ROW==sqlite3_step(pXInfo) ){
if( sqlite3_column_int(pXInfo, 5) ){
/* int iCid = sqlite3_column_int(pXInfo, 0); */
const char *zCol = (const char*)sqlite3_column_text(pXInfo, 2);
const char *zDesc = sqlite3_column_int(pXInfo, 3) ? " DESC" : "";
z = rbuMPrintf(p, "%z%s\"%w\"%s", z, zSep, zCol, zDesc);
zSep = ", ";
}
}
z = rbuMPrintf(p, "%z)", z);
rbuFinalize(p, pXInfo);
}
return z;
}
/*
** This function creates the second imposter table used when writing to
** a table b-tree where the table has an external primary key. If the
** iterator passed as the second argument does not currently point to
** a table (not index) with an external primary key, this function is a
** no-op.
**
** Assuming the iterator does point to a table with an external PK, this
** function creates a WITHOUT ROWID imposter table named "rbu_imposter2"
** used to access that PK index. For example, if the target table is
** declared as follows:
**
** CREATE TABLE t1(a, b TEXT, c REAL, PRIMARY KEY(b, c));
**
** then the imposter table schema is:
**
** CREATE TABLE rbu_imposter2(c1 TEXT, c2 REAL, id INTEGER) WITHOUT ROWID;
**
*/
static void rbuCreateImposterTable2(sqlite3rbu *p, RbuObjIter *pIter){
if( p->rc==SQLITE_OK && pIter->eType==RBU_PK_EXTERNAL ){
int tnum = pIter->iPkTnum; /* Root page of PK index */
sqlite3_stmt *pQuery = 0; /* SELECT name ... WHERE rootpage = $tnum */
const char *zIdx = 0; /* Name of PK index */
sqlite3_stmt *pXInfo = 0; /* PRAGMA main.index_xinfo = $zIdx */
const char *zComma = "";
char *zCols = 0; /* Used to build up list of table cols */
char *zPk = 0; /* Used to build up table PK declaration */
/* Figure out the name of the primary key index for the current table.
** This is needed for the argument to "PRAGMA index_xinfo". Set
** zIdx to point to a nul-terminated string containing this name. */
p->rc = prepareAndCollectError(p->dbMain, &pQuery, &p->zErrmsg,
"SELECT name FROM sqlite_master WHERE rootpage = ?"
);
if( p->rc==SQLITE_OK ){
sqlite3_bind_int(pQuery, 1, tnum);
if( SQLITE_ROW==sqlite3_step(pQuery) ){
zIdx = (const char*)sqlite3_column_text(pQuery, 0);
}
}
if( zIdx ){
p->rc = prepareFreeAndCollectError(p->dbMain, &pXInfo, &p->zErrmsg,
sqlite3_mprintf("PRAGMA main.index_xinfo = %Q", zIdx)
);
}
rbuFinalize(p, pQuery);
while( p->rc==SQLITE_OK && SQLITE_ROW==sqlite3_step(pXInfo) ){
int bKey = sqlite3_column_int(pXInfo, 5);
if( bKey ){
int iCid = sqlite3_column_int(pXInfo, 1);
int bDesc = sqlite3_column_int(pXInfo, 3);
const char *zCollate = (const char*)sqlite3_column_text(pXInfo, 4);
zCols = rbuMPrintf(p, "%z%sc%d %s COLLATE %s", zCols, zComma,
iCid, pIter->azTblType[iCid], zCollate
);
zPk = rbuMPrintf(p, "%z%sc%d%s", zPk, zComma, iCid, bDesc?" DESC":"");
zComma = ", ";
}
}
zCols = rbuMPrintf(p, "%z, id INTEGER", zCols);
rbuFinalize(p, pXInfo);
sqlite3_test_control(SQLITE_TESTCTRL_IMPOSTER, p->dbMain, "main", 1, tnum);
rbuMPrintfExec(p, p->dbMain,
"CREATE TABLE rbu_imposter2(%z, PRIMARY KEY(%z)) WITHOUT ROWID",
zCols, zPk
);
sqlite3_test_control(SQLITE_TESTCTRL_IMPOSTER, p->dbMain, "main", 0, 0);
}
}
/*
** If an error has already occurred when this function is called, it
** immediately returns zero (without doing any work). Or, if an error
** occurs during the execution of this function, it sets the error code
** in the sqlite3rbu object indicated by the first argument and returns
** zero.
**
** The iterator passed as the second argument is guaranteed to point to
** a table (not an index) when this function is called. This function
** attempts to create any imposter table required to write to the main
** table b-tree of the table before returning. Non-zero is returned if
** an imposter table are created, or zero otherwise.
**
** An imposter table is required in all cases except RBU_PK_VTAB. Only
** virtual tables are written to directly. The imposter table has the
** same schema as the actual target table (less any UNIQUE constraints).
** More precisely, the "same schema" means the same columns, types,
** collation sequences. For tables that do not have an external PRIMARY
** KEY, it also means the same PRIMARY KEY declaration.
*/
static void rbuCreateImposterTable(sqlite3rbu *p, RbuObjIter *pIter){
if( p->rc==SQLITE_OK && pIter->eType!=RBU_PK_VTAB ){
int tnum = pIter->iTnum;
const char *zComma = "";
char *zSql = 0;
int iCol;
sqlite3_test_control(SQLITE_TESTCTRL_IMPOSTER, p->dbMain, "main", 0, 1);
for(iCol=0; p->rc==SQLITE_OK && iCol<pIter->nTblCol; iCol++){
const char *zPk = "";
const char *zCol = pIter->azTblCol[iCol];
const char *zColl = 0;
p->rc = sqlite3_table_column_metadata(
p->dbMain, "main", pIter->zTbl, zCol, 0, &zColl, 0, 0, 0
);
if( pIter->eType==RBU_PK_IPK && pIter->abTblPk[iCol] ){
/* If the target table column is an "INTEGER PRIMARY KEY", add
** "PRIMARY KEY" to the imposter table column declaration. */
zPk = "PRIMARY KEY ";
}
zSql = rbuMPrintf(p, "%z%s\"%w\" %s %sCOLLATE %s%s",
zSql, zComma, zCol, pIter->azTblType[iCol], zPk, zColl,
(pIter->abNotNull[iCol] ? " NOT NULL" : "")
);
zComma = ", ";
}
if( pIter->eType==RBU_PK_WITHOUT_ROWID ){
char *zPk = rbuWithoutRowidPK(p, pIter);
if( zPk ){
zSql = rbuMPrintf(p, "%z, %z", zSql, zPk);
}
}
sqlite3_test_control(SQLITE_TESTCTRL_IMPOSTER, p->dbMain, "main", 1, tnum);
rbuMPrintfExec(p, p->dbMain, "CREATE TABLE \"rbu_imp_%w\"(%z)%s",
pIter->zTbl, zSql,
(pIter->eType==RBU_PK_WITHOUT_ROWID ? " WITHOUT ROWID" : "")
);
sqlite3_test_control(SQLITE_TESTCTRL_IMPOSTER, p->dbMain, "main", 0, 0);
}
}
/*
** Prepare a statement used to insert rows into the "rbu_tmp_xxx" table.
** Specifically a statement of the form:
**
** INSERT INTO rbu_tmp_xxx VALUES(?, ?, ? ...);
**
** The number of bound variables is equal to the number of columns in
** the target table, plus one (for the rbu_control column), plus one more
** (for the rbu_rowid column) if the target table is an implicit IPK or
** virtual table.
*/
static void rbuObjIterPrepareTmpInsert(
sqlite3rbu *p,
RbuObjIter *pIter,
const char *zCollist,
const char *zRbuRowid
){
int bRbuRowid = (pIter->eType==RBU_PK_EXTERNAL || pIter->eType==RBU_PK_NONE);
char *zBind = rbuObjIterGetBindlist(p, pIter->nTblCol + 1 + bRbuRowid);
if( zBind ){
assert( pIter->pTmpInsert==0 );
p->rc = prepareFreeAndCollectError(
p->dbRbu, &pIter->pTmpInsert, &p->zErrmsg, sqlite3_mprintf(
"INSERT INTO %s.'rbu_tmp_%q'(rbu_control,%s%s) VALUES(%z)",
p->zStateDb, pIter->zDataTbl, zCollist, zRbuRowid, zBind
));
}
}
static void rbuTmpInsertFunc(
sqlite3_context *pCtx,
int nVal,
sqlite3_value **apVal
){
sqlite3rbu *p = sqlite3_user_data(pCtx);
int rc = SQLITE_OK;
int i;
for(i=0; rc==SQLITE_OK && i<nVal; i++){
rc = sqlite3_bind_value(p->objiter.pTmpInsert, i+1, apVal[i]);
}
if( rc==SQLITE_OK ){
sqlite3_step(p->objiter.pTmpInsert);
rc = sqlite3_reset(p->objiter.pTmpInsert);
}
if( rc!=SQLITE_OK ){
sqlite3_result_error_code(pCtx, rc);
}
}
/*
** Ensure that the SQLite statement handles required to update the
** target database object currently indicated by the iterator passed
** as the second argument are available.
*/
static int rbuObjIterPrepareAll(
sqlite3rbu *p,
RbuObjIter *pIter,
int nOffset /* Add "LIMIT -1 OFFSET $nOffset" to SELECT */
){
assert( pIter->bCleanup==0 );
if( pIter->pSelect==0 && rbuObjIterCacheTableInfo(p, pIter)==SQLITE_OK ){
const int tnum = pIter->iTnum;
char *zCollist = 0; /* List of indexed columns */
char **pz = &p->zErrmsg;
const char *zIdx = pIter->zIdx;
char *zLimit = 0;
if( nOffset ){
zLimit = sqlite3_mprintf(" LIMIT -1 OFFSET %d", nOffset);
if( !zLimit ) p->rc = SQLITE_NOMEM;
}
if( zIdx ){
const char *zTbl = pIter->zTbl;
char *zImposterCols = 0; /* Columns for imposter table */
char *zImposterPK = 0; /* Primary key declaration for imposter */
char *zWhere = 0; /* WHERE clause on PK columns */
char *zBind = 0;
int nBind = 0;
assert( pIter->eType!=RBU_PK_VTAB );
zCollist = rbuObjIterGetIndexCols(
p, pIter, &zImposterCols, &zImposterPK, &zWhere, &nBind
);
zBind = rbuObjIterGetBindlist(p, nBind);
/* Create the imposter table used to write to this index. */
sqlite3_test_control(SQLITE_TESTCTRL_IMPOSTER, p->dbMain, "main", 0, 1);
sqlite3_test_control(SQLITE_TESTCTRL_IMPOSTER, p->dbMain, "main", 1,tnum);
rbuMPrintfExec(p, p->dbMain,
"CREATE TABLE \"rbu_imp_%w\"( %s, PRIMARY KEY( %s ) ) WITHOUT ROWID",
zTbl, zImposterCols, zImposterPK
);
sqlite3_test_control(SQLITE_TESTCTRL_IMPOSTER, p->dbMain, "main", 0, 0);
/* Create the statement to insert index entries */
pIter->nCol = nBind;
if( p->rc==SQLITE_OK ){
p->rc = prepareFreeAndCollectError(
p->dbMain, &pIter->pInsert, &p->zErrmsg,
sqlite3_mprintf("INSERT INTO \"rbu_imp_%w\" VALUES(%s)", zTbl, zBind)
);
}
/* And to delete index entries */
if( p->rc==SQLITE_OK ){
p->rc = prepareFreeAndCollectError(
p->dbMain, &pIter->pDelete, &p->zErrmsg,
sqlite3_mprintf("DELETE FROM \"rbu_imp_%w\" WHERE %s", zTbl, zWhere)
);
}
/* Create the SELECT statement to read keys in sorted order */
if( p->rc==SQLITE_OK ){
char *zSql;
if( pIter->eType==RBU_PK_EXTERNAL || pIter->eType==RBU_PK_NONE ){
zSql = sqlite3_mprintf(
"SELECT %s, rbu_control FROM %s.'rbu_tmp_%q' ORDER BY %s%s",
zCollist, p->zStateDb, pIter->zDataTbl,
zCollist, zLimit
);
}else{
zSql = sqlite3_mprintf(
"SELECT %s, rbu_control FROM '%q' "
"WHERE typeof(rbu_control)='integer' AND rbu_control!=1 "
"UNION ALL "
"SELECT %s, rbu_control FROM %s.'rbu_tmp_%q' "
"ORDER BY %s%s",
zCollist, pIter->zDataTbl,
zCollist, p->zStateDb, pIter->zDataTbl,
zCollist, zLimit
);
}
p->rc = prepareFreeAndCollectError(p->dbRbu, &pIter->pSelect, pz, zSql);
}
sqlite3_free(zImposterCols);
sqlite3_free(zImposterPK);
sqlite3_free(zWhere);
sqlite3_free(zBind);
}else{
int bRbuRowid = (pIter->eType==RBU_PK_VTAB || pIter->eType==RBU_PK_NONE);
const char *zTbl = pIter->zTbl; /* Table this step applies to */
const char *zWrite; /* Imposter table name */
char *zBindings = rbuObjIterGetBindlist(p, pIter->nTblCol + bRbuRowid);
char *zWhere = rbuObjIterGetWhere(p, pIter);
char *zOldlist = rbuObjIterGetOldlist(p, pIter, "old");
char *zNewlist = rbuObjIterGetOldlist(p, pIter, "new");
zCollist = rbuObjIterGetCollist(p, pIter);
pIter->nCol = pIter->nTblCol;
/* Create the imposter table or tables (if required). */
rbuCreateImposterTable(p, pIter);
rbuCreateImposterTable2(p, pIter);
zWrite = (pIter->eType==RBU_PK_VTAB ? "" : "rbu_imp_");
/* Create the INSERT statement to write to the target PK b-tree */
if( p->rc==SQLITE_OK ){
p->rc = prepareFreeAndCollectError(p->dbMain, &pIter->pInsert, pz,
sqlite3_mprintf(
"INSERT INTO \"%s%w\"(%s%s) VALUES(%s)",
zWrite, zTbl, zCollist, (bRbuRowid ? ", _rowid_" : ""), zBindings
)
);
}
/* Create the DELETE statement to write to the target PK b-tree */
if( p->rc==SQLITE_OK ){
p->rc = prepareFreeAndCollectError(p->dbMain, &pIter->pDelete, pz,
sqlite3_mprintf(
"DELETE FROM \"%s%w\" WHERE %s", zWrite, zTbl, zWhere
)
);
}
if( pIter->abIndexed ){
const char *zRbuRowid = "";
if( pIter->eType==RBU_PK_EXTERNAL || pIter->eType==RBU_PK_NONE ){
zRbuRowid = ", rbu_rowid";
}
/* Create the rbu_tmp_xxx table and the triggers to populate it. */
rbuMPrintfExec(p, p->dbRbu,
"CREATE TABLE IF NOT EXISTS %s.'rbu_tmp_%q' AS "
"SELECT *%s FROM '%q' WHERE 0;"
, p->zStateDb, pIter->zDataTbl
, (pIter->eType==RBU_PK_EXTERNAL ? ", 0 AS rbu_rowid" : "")
, pIter->zDataTbl
);
rbuMPrintfExec(p, p->dbMain,
"CREATE TEMP TRIGGER rbu_delete_tr BEFORE DELETE ON \"%s%w\" "
"BEGIN "
" SELECT rbu_tmp_insert(2, %s);"
"END;"
"CREATE TEMP TRIGGER rbu_update1_tr BEFORE UPDATE ON \"%s%w\" "
"BEGIN "
" SELECT rbu_tmp_insert(2, %s);"
"END;"
"CREATE TEMP TRIGGER rbu_update2_tr AFTER UPDATE ON \"%s%w\" "
"BEGIN "
" SELECT rbu_tmp_insert(3, %s);"
"END;",
zWrite, zTbl, zOldlist,
zWrite, zTbl, zOldlist,
zWrite, zTbl, zNewlist
);
if( pIter->eType==RBU_PK_EXTERNAL || pIter->eType==RBU_PK_NONE ){
rbuMPrintfExec(p, p->dbMain,
"CREATE TEMP TRIGGER rbu_insert_tr AFTER INSERT ON \"%s%w\" "
"BEGIN "
" SELECT rbu_tmp_insert(0, %s);"
"END;",
zWrite, zTbl, zNewlist
);
}
rbuObjIterPrepareTmpInsert(p, pIter, zCollist, zRbuRowid);
}
/* Create the SELECT statement to read keys from data_xxx */
if( p->rc==SQLITE_OK ){
p->rc = prepareFreeAndCollectError(p->dbRbu, &pIter->pSelect, pz,
sqlite3_mprintf(
"SELECT %s, rbu_control%s FROM '%q'%s",
zCollist, (bRbuRowid ? ", rbu_rowid" : ""),
pIter->zDataTbl, zLimit
)
);
}
sqlite3_free(zWhere);
sqlite3_free(zOldlist);
sqlite3_free(zNewlist);
sqlite3_free(zBindings);
}
sqlite3_free(zCollist);
sqlite3_free(zLimit);
}
return p->rc;
}
/*
** Set output variable *ppStmt to point to an UPDATE statement that may
** be used to update the imposter table for the main table b-tree of the
** table object that pIter currently points to, assuming that the
** rbu_control column of the data_xyz table contains zMask.
**
** If the zMask string does not specify any columns to update, then this
** is not an error. Output variable *ppStmt is set to NULL in this case.
*/
static int rbuGetUpdateStmt(
sqlite3rbu *p, /* RBU handle */
RbuObjIter *pIter, /* Object iterator */
const char *zMask, /* rbu_control value ('x.x.') */
sqlite3_stmt **ppStmt /* OUT: UPDATE statement handle */
){
RbuUpdateStmt **pp;
RbuUpdateStmt *pUp = 0;
int nUp = 0;
/* In case an error occurs */
*ppStmt = 0;
/* Search for an existing statement. If one is found, shift it to the front
** of the LRU queue and return immediately. Otherwise, leave nUp pointing
** to the number of statements currently in the cache and pUp to the
** last object in the list. */
for(pp=&pIter->pRbuUpdate; *pp; pp=&((*pp)->pNext)){
pUp = *pp;
if( strcmp(pUp->zMask, zMask)==0 ){
*pp = pUp->pNext;
pUp->pNext = pIter->pRbuUpdate;
pIter->pRbuUpdate = pUp;
*ppStmt = pUp->pUpdate;
return SQLITE_OK;
}
nUp++;
}
assert( pUp==0 || pUp->pNext==0 );
if( nUp>=SQLITE_RBU_UPDATE_CACHESIZE ){
for(pp=&pIter->pRbuUpdate; *pp!=pUp; pp=&((*pp)->pNext));
*pp = 0;
sqlite3_finalize(pUp->pUpdate);
pUp->pUpdate = 0;
}else{
pUp = (RbuUpdateStmt*)rbuMalloc(p, sizeof(RbuUpdateStmt)+pIter->nTblCol+1);
}
if( pUp ){
char *zWhere = rbuObjIterGetWhere(p, pIter);
char *zSet = rbuObjIterGetSetlist(p, pIter, zMask);
char *zUpdate = 0;
pUp->zMask = (char*)&pUp[1];
memcpy(pUp->zMask, zMask, pIter->nTblCol);
pUp->pNext = pIter->pRbuUpdate;
pIter->pRbuUpdate = pUp;
if( zSet ){
const char *zPrefix = "";
if( pIter->eType!=RBU_PK_VTAB ) zPrefix = "rbu_imp_";
zUpdate = sqlite3_mprintf("UPDATE \"%s%w\" SET %s WHERE %s",
zPrefix, pIter->zTbl, zSet, zWhere
);
p->rc = prepareFreeAndCollectError(
p->dbMain, &pUp->pUpdate, &p->zErrmsg, zUpdate
);
*ppStmt = pUp->pUpdate;
}
sqlite3_free(zWhere);
sqlite3_free(zSet);
}
return p->rc;
}
static sqlite3 *rbuOpenDbhandle(sqlite3rbu *p, const char *zName){
sqlite3 *db = 0;
if( p->rc==SQLITE_OK ){
const int flags = SQLITE_OPEN_READWRITE|SQLITE_OPEN_CREATE|SQLITE_OPEN_URI;
p->rc = sqlite3_open_v2(zName, &db, flags, p->zVfsName);
if( p->rc ){
p->zErrmsg = sqlite3_mprintf("%s", sqlite3_errmsg(db));
sqlite3_close(db);
db = 0;
}
}
return db;
}
/*
** Open the database handle and attach the RBU database as "rbu". If an
** error occurs, leave an error code and message in the RBU handle.
*/
static void rbuOpenDatabase(sqlite3rbu *p){
assert( p->rc==SQLITE_OK );
assert( p->dbMain==0 && p->dbRbu==0 );
p->eStage = 0;
p->dbMain = rbuOpenDbhandle(p, p->zTarget);
p->dbRbu = rbuOpenDbhandle(p, p->zRbu);
/* If using separate RBU and state databases, attach the state database to
** the RBU db handle now. */
if( p->zState ){
rbuMPrintfExec(p, p->dbRbu, "ATTACH %Q AS stat", p->zState);
memcpy(p->zStateDb, "stat", 4);
}else{
memcpy(p->zStateDb, "main", 4);
}
if( p->rc==SQLITE_OK ){
p->rc = sqlite3_create_function(p->dbMain,
"rbu_tmp_insert", -1, SQLITE_UTF8, (void*)p, rbuTmpInsertFunc, 0, 0
);
}
if( p->rc==SQLITE_OK ){
p->rc = sqlite3_create_function(p->dbMain,
"rbu_fossil_delta", 2, SQLITE_UTF8, 0, rbuFossilDeltaFunc, 0, 0
);
}
if( p->rc==SQLITE_OK ){
p->rc = sqlite3_create_function(p->dbRbu,
"rbu_target_name", 1, SQLITE_UTF8, (void*)p, rbuTargetNameFunc, 0, 0
);
}
if( p->rc==SQLITE_OK ){
p->rc = sqlite3_file_control(p->dbMain, "main", SQLITE_FCNTL_RBU, (void*)p);
}
rbuMPrintfExec(p, p->dbMain, "SELECT * FROM sqlite_master");
/* Mark the database file just opened as an RBU target database. If
** this call returns SQLITE_NOTFOUND, then the RBU vfs is not in use.
** This is an error. */
if( p->rc==SQLITE_OK ){
p->rc = sqlite3_file_control(p->dbMain, "main", SQLITE_FCNTL_RBU, (void*)p);
}
if( p->rc==SQLITE_NOTFOUND ){
p->rc = SQLITE_ERROR;
p->zErrmsg = sqlite3_mprintf("rbu vfs not found");
}
}
/*
** This routine is a copy of the sqlite3FileSuffix3() routine from the core.
** It is a no-op unless SQLITE_ENABLE_8_3_NAMES is defined.
**
** If SQLITE_ENABLE_8_3_NAMES is set at compile-time and if the database
** filename in zBaseFilename is a URI with the "8_3_names=1" parameter and
** if filename in z[] has a suffix (a.k.a. "extension") that is longer than
** three characters, then shorten the suffix on z[] to be the last three
** characters of the original suffix.
**
** If SQLITE_ENABLE_8_3_NAMES is set to 2 at compile-time, then always
** do the suffix shortening regardless of URI parameter.
**
** Examples:
**
** test.db-journal => test.nal
** test.db-wal => test.wal
** test.db-shm => test.shm
** test.db-mj7f3319fa => test.9fa
*/
static void rbuFileSuffix3(const char *zBase, char *z){
#ifdef SQLITE_ENABLE_8_3_NAMES
#if SQLITE_ENABLE_8_3_NAMES<2
if( sqlite3_uri_boolean(zBase, "8_3_names", 0) )
#endif
{
int i, sz;
sz = sqlite3Strlen30(z);
for(i=sz-1; i>0 && z[i]!='/' && z[i]!='.'; i--){}
if( z[i]=='.' && ALWAYS(sz>i+4) ) memmove(&z[i+1], &z[sz-3], 4);
}
#endif
}
/*
** Return the current wal-index header checksum for the target database
** as a 64-bit integer.
**
** The checksum is store in the first page of xShmMap memory as an 8-byte
** blob starting at byte offset 40.
*/
static i64 rbuShmChecksum(sqlite3rbu *p){
i64 iRet = 0;
if( p->rc==SQLITE_OK ){
sqlite3_file *pDb = p->pTargetFd->pReal;
u32 volatile *ptr;
p->rc = pDb->pMethods->xShmMap(pDb, 0, 32*1024, 0, (void volatile**)&ptr);
if( p->rc==SQLITE_OK ){
iRet = ((i64)ptr[10] << 32) + ptr[11];
}
}
return iRet;
}
/*
** This function is called as part of initializing or reinitializing an
** incremental checkpoint.
**
** It populates the sqlite3rbu.aFrame[] array with the set of
** (wal frame -> db page) copy operations required to checkpoint the
** current wal file, and obtains the set of shm locks required to safely
** perform the copy operations directly on the file-system.
**
** If argument pState is not NULL, then the incremental checkpoint is
** being resumed. In this case, if the checksum of the wal-index-header
** following recovery is not the same as the checksum saved in the RbuState
** object, then the rbu handle is set to DONE state. This occurs if some
** other client appends a transaction to the wal file in the middle of
** an incremental checkpoint.
*/
static void rbuSetupCheckpoint(sqlite3rbu *p, RbuState *pState){
/* If pState is NULL, then the wal file may not have been opened and
** recovered. Running a read-statement here to ensure that doing so
** does not interfere with the "capture" process below. */
if( pState==0 ){
p->eStage = 0;
if( p->rc==SQLITE_OK ){
p->rc = sqlite3_exec(p->dbMain, "SELECT * FROM sqlite_master", 0, 0, 0);
}
}
/* Assuming no error has occurred, run a "restart" checkpoint with the
** sqlite3rbu.eStage variable set to CAPTURE. This turns on the following
** special behaviour in the rbu VFS:
**
** * If the exclusive shm WRITER or READ0 lock cannot be obtained,
** the checkpoint fails with SQLITE_BUSY (normally SQLite would
** proceed with running a passive checkpoint instead of failing).
**
** * Attempts to read from the *-wal file or write to the database file
** do not perform any IO. Instead, the frame/page combinations that
** would be read/written are recorded in the sqlite3rbu.aFrame[]
** array.
**
** * Calls to xShmLock(UNLOCK) to release the exclusive shm WRITER,
** READ0 and CHECKPOINT locks taken as part of the checkpoint are
** no-ops. These locks will not be released until the connection
** is closed.
**
** * Attempting to xSync() the database file causes an SQLITE_INTERNAL
** error.
**
** As a result, unless an error (i.e. OOM or SQLITE_BUSY) occurs, the
** checkpoint below fails with SQLITE_INTERNAL, and leaves the aFrame[]
** array populated with a set of (frame -> page) mappings. Because the
** WRITER, CHECKPOINT and READ0 locks are still held, it is safe to copy
** data from the wal file into the database file according to the
** contents of aFrame[].
*/
if( p->rc==SQLITE_OK ){
int rc2;
p->eStage = RBU_STAGE_CAPTURE;
rc2 = sqlite3_exec(p->dbMain, "PRAGMA main.wal_checkpoint=restart", 0, 0,0);
if( rc2!=SQLITE_INTERNAL ) p->rc = rc2;
}
if( p->rc==SQLITE_OK ){
p->eStage = RBU_STAGE_CKPT;
p->nStep = (pState ? pState->nRow : 0);
p->aBuf = rbuMalloc(p, p->pgsz);
p->iWalCksum = rbuShmChecksum(p);
}
if( p->rc==SQLITE_OK && pState && pState->iWalCksum!=p->iWalCksum ){
p->rc = SQLITE_DONE;
p->eStage = RBU_STAGE_DONE;
}
}
/*
** Called when iAmt bytes are read from offset iOff of the wal file while
** the rbu object is in capture mode. Record the frame number of the frame
** being read in the aFrame[] array.
*/
static int rbuCaptureWalRead(sqlite3rbu *pRbu, i64 iOff, int iAmt){
const u32 mReq = (1<<WAL_LOCK_WRITE)|(1<<WAL_LOCK_CKPT)|(1<<WAL_LOCK_READ0);
u32 iFrame;
if( pRbu->mLock!=mReq ){
pRbu->rc = SQLITE_BUSY;
return SQLITE_INTERNAL;
}
pRbu->pgsz = iAmt;
if( pRbu->nFrame==pRbu->nFrameAlloc ){
int nNew = (pRbu->nFrameAlloc ? pRbu->nFrameAlloc : 64) * 2;
RbuFrame *aNew;
aNew = (RbuFrame*)sqlite3_realloc(pRbu->aFrame, nNew * sizeof(RbuFrame));
if( aNew==0 ) return SQLITE_NOMEM;
pRbu->aFrame = aNew;
pRbu->nFrameAlloc = nNew;
}
iFrame = (u32)((iOff-32) / (i64)(iAmt+24)) + 1;
if( pRbu->iMaxFrame<iFrame ) pRbu->iMaxFrame = iFrame;
pRbu->aFrame[pRbu->nFrame].iWalFrame = iFrame;
pRbu->aFrame[pRbu->nFrame].iDbPage = 0;
pRbu->nFrame++;
return SQLITE_OK;
}
/*
** Called when a page of data is written to offset iOff of the database
** file while the rbu handle is in capture mode. Record the page number
** of the page being written in the aFrame[] array.
*/
static int rbuCaptureDbWrite(sqlite3rbu *pRbu, i64 iOff){
pRbu->aFrame[pRbu->nFrame-1].iDbPage = (u32)(iOff / pRbu->pgsz) + 1;
return SQLITE_OK;
}
/*
** This is called as part of an incremental checkpoint operation. Copy
** a single frame of data from the wal file into the database file, as
** indicated by the RbuFrame object.
*/
static void rbuCheckpointFrame(sqlite3rbu *p, RbuFrame *pFrame){
sqlite3_file *pWal = p->pTargetFd->pWalFd->pReal;
sqlite3_file *pDb = p->pTargetFd->pReal;
i64 iOff;
assert( p->rc==SQLITE_OK );
iOff = (i64)(pFrame->iWalFrame-1) * (p->pgsz + 24) + 32 + 24;
p->rc = pWal->pMethods->xRead(pWal, p->aBuf, p->pgsz, iOff);
if( p->rc ) return;
iOff = (i64)(pFrame->iDbPage-1) * p->pgsz;
p->rc = pDb->pMethods->xWrite(pDb, p->aBuf, p->pgsz, iOff);
}
/*
** Take an EXCLUSIVE lock on the database file.
*/
static void rbuLockDatabase(sqlite3rbu *p){
sqlite3_file *pReal = p->pTargetFd->pReal;
assert( p->rc==SQLITE_OK );
p->rc = pReal->pMethods->xLock(pReal, SQLITE_LOCK_SHARED);
if( p->rc==SQLITE_OK ){
p->rc = pReal->pMethods->xLock(pReal, SQLITE_LOCK_EXCLUSIVE);
}
}
#if defined(_WIN32_WCE)
static LPWSTR rbuWinUtf8ToUnicode(const char *zFilename){
int nChar;
LPWSTR zWideFilename;
nChar = MultiByteToWideChar(CP_UTF8, 0, zFilename, -1, NULL, 0);
if( nChar==0 ){
return 0;
}
zWideFilename = sqlite3_malloc( nChar*sizeof(zWideFilename[0]) );
if( zWideFilename==0 ){
return 0;
}
memset(zWideFilename, 0, nChar*sizeof(zWideFilename[0]));
nChar = MultiByteToWideChar(CP_UTF8, 0, zFilename, -1, zWideFilename,
nChar);
if( nChar==0 ){
sqlite3_free(zWideFilename);
zWideFilename = 0;
}
return zWideFilename;
}
#endif
/*
** The RBU handle is currently in RBU_STAGE_OAL state, with a SHARED lock
** on the database file. This proc moves the *-oal file to the *-wal path,
** then reopens the database file (this time in vanilla, non-oal, WAL mode).
** If an error occurs, leave an error code and error message in the rbu
** handle.
*/
static void rbuMoveOalFile(sqlite3rbu *p){
const char *zBase = sqlite3_db_filename(p->dbMain, "main");
char *zWal = sqlite3_mprintf("%s-wal", zBase);
char *zOal = sqlite3_mprintf("%s-oal", zBase);
assert( p->eStage==RBU_STAGE_MOVE );
assert( p->rc==SQLITE_OK && p->zErrmsg==0 );
if( zWal==0 || zOal==0 ){
p->rc = SQLITE_NOMEM;
}else{
/* Move the *-oal file to *-wal. At this point connection p->db is
** holding a SHARED lock on the target database file (because it is
** in WAL mode). So no other connection may be writing the db.
**
** In order to ensure that there are no database readers, an EXCLUSIVE
** lock is obtained here before the *-oal is moved to *-wal.
*/
rbuLockDatabase(p);
if( p->rc==SQLITE_OK ){
rbuFileSuffix3(zBase, zWal);
rbuFileSuffix3(zBase, zOal);
/* Re-open the databases. */
rbuObjIterFinalize(&p->objiter);
sqlite3_close(p->dbMain);
sqlite3_close(p->dbRbu);
p->dbMain = 0;
p->dbRbu = 0;
#if defined(_WIN32_WCE)
{
LPWSTR zWideOal;
LPWSTR zWideWal;
zWideOal = rbuWinUtf8ToUnicode(zOal);
if( zWideOal ){
zWideWal = rbuWinUtf8ToUnicode(zWal);
if( zWideWal ){
if( MoveFileW(zWideOal, zWideWal) ){
p->rc = SQLITE_OK;
}else{
p->rc = SQLITE_IOERR;
}
sqlite3_free(zWideWal);
}else{
p->rc = SQLITE_IOERR_NOMEM;
}
sqlite3_free(zWideOal);
}else{
p->rc = SQLITE_IOERR_NOMEM;
}
}
#else
p->rc = rename(zOal, zWal) ? SQLITE_IOERR : SQLITE_OK;
#endif
if( p->rc==SQLITE_OK ){
rbuOpenDatabase(p);
rbuSetupCheckpoint(p, 0);
}
}
}
sqlite3_free(zWal);
sqlite3_free(zOal);
}
/*
** The SELECT statement iterating through the keys for the current object
** (p->objiter.pSelect) currently points to a valid row. This function
** determines the type of operation requested by this row and returns
** one of the following values to indicate the result:
**
** * RBU_INSERT
** * RBU_DELETE
** * RBU_IDX_DELETE
** * RBU_UPDATE
**
** If RBU_UPDATE is returned, then output variable *pzMask is set to
** point to the text value indicating the columns to update.
**
** If the rbu_control field contains an invalid value, an error code and
** message are left in the RBU handle and zero returned.
*/
static int rbuStepType(sqlite3rbu *p, const char **pzMask){
int iCol = p->objiter.nCol; /* Index of rbu_control column */
int res = 0; /* Return value */
switch( sqlite3_column_type(p->objiter.pSelect, iCol) ){
case SQLITE_INTEGER: {
int iVal = sqlite3_column_int(p->objiter.pSelect, iCol);
if( iVal==0 ){
res = RBU_INSERT;
}else if( iVal==1 ){
res = RBU_DELETE;
}else if( iVal==2 ){
res = RBU_IDX_DELETE;
}else if( iVal==3 ){
res = RBU_IDX_INSERT;
}
break;
}
case SQLITE_TEXT: {
const unsigned char *z = sqlite3_column_text(p->objiter.pSelect, iCol);
if( z==0 ){
p->rc = SQLITE_NOMEM;
}else{
*pzMask = (const char*)z;
}
res = RBU_UPDATE;
break;
}
default:
break;
}
if( res==0 ){
rbuBadControlError(p);
}
return res;
}
#ifdef SQLITE_DEBUG
/*
** Assert that column iCol of statement pStmt is named zName.
*/
static void assertColumnName(sqlite3_stmt *pStmt, int iCol, const char *zName){
const char *zCol = sqlite3_column_name(pStmt, iCol);
assert( 0==sqlite3_stricmp(zName, zCol) );
}
#else
# define assertColumnName(x,y,z)
#endif
/*
** This function does the work for an sqlite3rbu_step() call.
**
** The object-iterator (p->objiter) currently points to a valid object,
** and the input cursor (p->objiter.pSelect) currently points to a valid
** input row. Perform whatever processing is required and return.
**
** If no error occurs, SQLITE_OK is returned. Otherwise, an error code
** and message is left in the RBU handle and a copy of the error code
** returned.
*/
static int rbuStep(sqlite3rbu *p){
RbuObjIter *pIter = &p->objiter;
const char *zMask = 0;
int i;
int eType = rbuStepType(p, &zMask);
if( eType ){
assert( eType!=RBU_UPDATE || pIter->zIdx==0 );
if( pIter->zIdx==0 && eType==RBU_IDX_DELETE ){
rbuBadControlError(p);
}
else if(
eType==RBU_INSERT
|| eType==RBU_DELETE
|| eType==RBU_IDX_DELETE
|| eType==RBU_IDX_INSERT
){
sqlite3_value *pVal;
sqlite3_stmt *pWriter;
assert( eType!=RBU_UPDATE );
assert( eType!=RBU_DELETE || pIter->zIdx==0 );
if( eType==RBU_IDX_DELETE || eType==RBU_DELETE ){
pWriter = pIter->pDelete;
}else{
pWriter = pIter->pInsert;
}
for(i=0; i<pIter->nCol; i++){
/* If this is an INSERT into a table b-tree and the table has an
** explicit INTEGER PRIMARY KEY, check that this is not an attempt
** to write a NULL into the IPK column. That is not permitted. */
if( eType==RBU_INSERT
&& pIter->zIdx==0 && pIter->eType==RBU_PK_IPK && pIter->abTblPk[i]
&& sqlite3_column_type(pIter->pSelect, i)==SQLITE_NULL
){
p->rc = SQLITE_MISMATCH;
p->zErrmsg = sqlite3_mprintf("datatype mismatch");
goto step_out;
}
if( eType==RBU_DELETE && pIter->abTblPk[i]==0 ){
continue;
}
pVal = sqlite3_column_value(pIter->pSelect, i);
p->rc = sqlite3_bind_value(pWriter, i+1, pVal);
if( p->rc ) goto step_out;
}
if( pIter->zIdx==0
&& (pIter->eType==RBU_PK_VTAB || pIter->eType==RBU_PK_NONE)
){
/* For a virtual table, or a table with no primary key, the
** SELECT statement is:
**
** SELECT <cols>, rbu_control, rbu_rowid FROM ....
**
** Hence column_value(pIter->nCol+1).
*/
assertColumnName(pIter->pSelect, pIter->nCol+1, "rbu_rowid");
pVal = sqlite3_column_value(pIter->pSelect, pIter->nCol+1);
p->rc = sqlite3_bind_value(pWriter, pIter->nCol+1, pVal);
}
if( p->rc==SQLITE_OK ){
sqlite3_step(pWriter);
p->rc = resetAndCollectError(pWriter, &p->zErrmsg);
}
}else{
sqlite3_value *pVal;
sqlite3_stmt *pUpdate = 0;
assert( eType==RBU_UPDATE );
rbuGetUpdateStmt(p, pIter, zMask, &pUpdate);
if( pUpdate ){
for(i=0; p->rc==SQLITE_OK && i<pIter->nCol; i++){
char c = zMask[pIter->aiSrcOrder[i]];
pVal = sqlite3_column_value(pIter->pSelect, i);
if( pIter->abTblPk[i] || c!='.' ){
p->rc = sqlite3_bind_value(pUpdate, i+1, pVal);
}
}
if( p->rc==SQLITE_OK
&& (pIter->eType==RBU_PK_VTAB || pIter->eType==RBU_PK_NONE)
){
/* Bind the rbu_rowid value to column _rowid_ */
assertColumnName(pIter->pSelect, pIter->nCol+1, "rbu_rowid");
pVal = sqlite3_column_value(pIter->pSelect, pIter->nCol+1);
p->rc = sqlite3_bind_value(pUpdate, pIter->nCol+1, pVal);
}
if( p->rc==SQLITE_OK ){
sqlite3_step(pUpdate);
p->rc = resetAndCollectError(pUpdate, &p->zErrmsg);
}
}
}
}
step_out:
return p->rc;
}
/*
** Increment the schema cookie of the main database opened by p->dbMain.
*/
static void rbuIncrSchemaCookie(sqlite3rbu *p){
if( p->rc==SQLITE_OK ){
int iCookie = 1000000;
sqlite3_stmt *pStmt;
p->rc = prepareAndCollectError(p->dbMain, &pStmt, &p->zErrmsg,
"PRAGMA schema_version"
);
if( p->rc==SQLITE_OK ){
/* Coverage: it may be that this sqlite3_step() cannot fail. There
** is already a transaction open, so the prepared statement cannot
** throw an SQLITE_SCHEMA exception. The only database page the
** statement reads is page 1, which is guaranteed to be in the cache.
** And no memory allocations are required. */
if( SQLITE_ROW==sqlite3_step(pStmt) ){
iCookie = sqlite3_column_int(pStmt, 0);
}
rbuFinalize(p, pStmt);
}
if( p->rc==SQLITE_OK ){
rbuMPrintfExec(p, p->dbMain, "PRAGMA schema_version = %d", iCookie+1);
}
}
}
/*
** Update the contents of the rbu_state table within the rbu database. The
** value stored in the RBU_STATE_STAGE column is eStage. All other values
** are determined by inspecting the rbu handle passed as the first argument.
*/
static void rbuSaveState(sqlite3rbu *p, int eStage){
if( p->rc==SQLITE_OK || p->rc==SQLITE_DONE ){
sqlite3_stmt *pInsert = 0;
int rc;
assert( p->zErrmsg==0 );
rc = prepareFreeAndCollectError(p->dbRbu, &pInsert, &p->zErrmsg,
sqlite3_mprintf(
"INSERT OR REPLACE INTO %s.rbu_state(k, v) VALUES "
"(%d, %d), "
"(%d, %Q), "
"(%d, %Q), "
"(%d, %d), "
"(%d, %d), "
"(%d, %lld), "
"(%d, %lld), "
"(%d, %lld) ",
p->zStateDb,
RBU_STATE_STAGE, eStage,
RBU_STATE_TBL, p->objiter.zTbl,
RBU_STATE_IDX, p->objiter.zIdx,
RBU_STATE_ROW, p->nStep,
RBU_STATE_PROGRESS, p->nProgress,
RBU_STATE_CKPT, p->iWalCksum,
RBU_STATE_COOKIE, (i64)p->pTargetFd->iCookie,
RBU_STATE_OALSZ, p->iOalSz
)
);
assert( pInsert==0 || rc==SQLITE_OK );
if( rc==SQLITE_OK ){
sqlite3_step(pInsert);
rc = sqlite3_finalize(pInsert);
}
if( rc!=SQLITE_OK ) p->rc = rc;
}
}
/*
** Step the RBU object.
*/
int sqlite3rbu_step(sqlite3rbu *p){
if( p ){
switch( p->eStage ){
case RBU_STAGE_OAL: {
RbuObjIter *pIter = &p->objiter;
while( p->rc==SQLITE_OK && pIter->zTbl ){
if( pIter->bCleanup ){
/* Clean up the rbu_tmp_xxx table for the previous table. It
** cannot be dropped as there are currently active SQL statements.
** But the contents can be deleted. */
if( pIter->abIndexed ){
rbuMPrintfExec(p, p->dbRbu,
"DELETE FROM %s.'rbu_tmp_%q'", p->zStateDb, pIter->zDataTbl
);
}
}else{
rbuObjIterPrepareAll(p, pIter, 0);
/* Advance to the next row to process. */
if( p->rc==SQLITE_OK ){
int rc = sqlite3_step(pIter->pSelect);
if( rc==SQLITE_ROW ){
p->nProgress++;
p->nStep++;
return rbuStep(p);
}
p->rc = sqlite3_reset(pIter->pSelect);
p->nStep = 0;
}
}
rbuObjIterNext(p, pIter);
}
if( p->rc==SQLITE_OK ){
assert( pIter->zTbl==0 );
rbuSaveState(p, RBU_STAGE_MOVE);
rbuIncrSchemaCookie(p);
if( p->rc==SQLITE_OK ){
p->rc = sqlite3_exec(p->dbMain, "COMMIT", 0, 0, &p->zErrmsg);
}
if( p->rc==SQLITE_OK ){
p->rc = sqlite3_exec(p->dbRbu, "COMMIT", 0, 0, &p->zErrmsg);
}
p->eStage = RBU_STAGE_MOVE;
}
break;
}
case RBU_STAGE_MOVE: {
if( p->rc==SQLITE_OK ){
rbuMoveOalFile(p);
p->nProgress++;
}
break;
}
case RBU_STAGE_CKPT: {
if( p->rc==SQLITE_OK ){
if( p->nStep>=p->nFrame ){
sqlite3_file *pDb = p->pTargetFd->pReal;
/* Sync the db file */
p->rc = pDb->pMethods->xSync(pDb, SQLITE_SYNC_NORMAL);
/* Update nBackfill */
if( p->rc==SQLITE_OK ){
void volatile *ptr;
p->rc = pDb->pMethods->xShmMap(pDb, 0, 32*1024, 0, &ptr);
if( p->rc==SQLITE_OK ){
((u32 volatile*)ptr)[24] = p->iMaxFrame;
}
}
if( p->rc==SQLITE_OK ){
p->eStage = RBU_STAGE_DONE;
p->rc = SQLITE_DONE;
}
}else{
RbuFrame *pFrame = &p->aFrame[p->nStep];
rbuCheckpointFrame(p, pFrame);
p->nStep++;
}
p->nProgress++;
}
break;
}
default:
break;
}
return p->rc;
}else{
return SQLITE_NOMEM;
}
}
/*
** Free an RbuState object allocated by rbuLoadState().
*/
static void rbuFreeState(RbuState *p){
if( p ){
sqlite3_free(p->zTbl);
sqlite3_free(p->zIdx);
sqlite3_free(p);
}
}
/*
** Allocate an RbuState object and load the contents of the rbu_state
** table into it. Return a pointer to the new object. It is the
** responsibility of the caller to eventually free the object using
** sqlite3_free().
**
** If an error occurs, leave an error code and message in the rbu handle
** and return NULL.
*/
static RbuState *rbuLoadState(sqlite3rbu *p){
RbuState *pRet = 0;
sqlite3_stmt *pStmt = 0;
int rc;
int rc2;
pRet = (RbuState*)rbuMalloc(p, sizeof(RbuState));
if( pRet==0 ) return 0;
rc = prepareFreeAndCollectError(p->dbRbu, &pStmt, &p->zErrmsg,
sqlite3_mprintf("SELECT k, v FROM %s.rbu_state", p->zStateDb)
);
while( rc==SQLITE_OK && SQLITE_ROW==sqlite3_step(pStmt) ){
switch( sqlite3_column_int(pStmt, 0) ){
case RBU_STATE_STAGE:
pRet->eStage = sqlite3_column_int(pStmt, 1);
if( pRet->eStage!=RBU_STAGE_OAL
&& pRet->eStage!=RBU_STAGE_MOVE
&& pRet->eStage!=RBU_STAGE_CKPT
){
p->rc = SQLITE_CORRUPT;
}
break;
case RBU_STATE_TBL:
pRet->zTbl = rbuStrndup((char*)sqlite3_column_text(pStmt, 1), &rc);
break;
case RBU_STATE_IDX:
pRet->zIdx = rbuStrndup((char*)sqlite3_column_text(pStmt, 1), &rc);
break;
case RBU_STATE_ROW:
pRet->nRow = sqlite3_column_int(pStmt, 1);
break;
case RBU_STATE_PROGRESS:
pRet->nProgress = sqlite3_column_int64(pStmt, 1);
break;
case RBU_STATE_CKPT:
pRet->iWalCksum = sqlite3_column_int64(pStmt, 1);
break;
case RBU_STATE_COOKIE:
pRet->iCookie = (u32)sqlite3_column_int64(pStmt, 1);
break;
case RBU_STATE_OALSZ:
pRet->iOalSz = (u32)sqlite3_column_int64(pStmt, 1);
break;
default:
rc = SQLITE_CORRUPT;
break;
}
}
rc2 = sqlite3_finalize(pStmt);
if( rc==SQLITE_OK ) rc = rc2;
p->rc = rc;
return pRet;
}
/*
** Compare strings z1 and z2, returning 0 if they are identical, or non-zero
** otherwise. Either or both argument may be NULL. Two NULL values are
** considered equal, and NULL is considered distinct from all other values.
*/
static int rbuStrCompare(const char *z1, const char *z2){
if( z1==0 && z2==0 ) return 0;
if( z1==0 || z2==0 ) return 1;
return (sqlite3_stricmp(z1, z2)!=0);
}
/*
** This function is called as part of sqlite3rbu_open() when initializing
** an rbu handle in OAL stage. If the rbu update has not started (i.e.
** the rbu_state table was empty) it is a no-op. Otherwise, it arranges
** things so that the next call to sqlite3rbu_step() continues on from
** where the previous rbu handle left off.
**
** If an error occurs, an error code and error message are left in the
** rbu handle passed as the first argument.
*/
static void rbuSetupOal(sqlite3rbu *p, RbuState *pState){
assert( p->rc==SQLITE_OK );
if( pState->zTbl ){
RbuObjIter *pIter = &p->objiter;
int rc = SQLITE_OK;
while( rc==SQLITE_OK && pIter->zTbl && (pIter->bCleanup
|| rbuStrCompare(pIter->zIdx, pState->zIdx)
|| rbuStrCompare(pIter->zTbl, pState->zTbl)
)){
rc = rbuObjIterNext(p, pIter);
}
if( rc==SQLITE_OK && !pIter->zTbl ){
rc = SQLITE_ERROR;
p->zErrmsg = sqlite3_mprintf("rbu_state mismatch error");
}
if( rc==SQLITE_OK ){
p->nStep = pState->nRow;
rc = rbuObjIterPrepareAll(p, &p->objiter, p->nStep);
}
p->rc = rc;
}
}
/*
** If there is a "*-oal" file in the file-system corresponding to the
** target database in the file-system, delete it. If an error occurs,
** leave an error code and error message in the rbu handle.
*/
static void rbuDeleteOalFile(sqlite3rbu *p){
char *zOal = rbuMPrintf(p, "%s-oal", p->zTarget);
if( zOal ){
sqlite3_vfs *pVfs = sqlite3_vfs_find(0);
assert( pVfs && p->rc==SQLITE_OK && p->zErrmsg==0 );
pVfs->xDelete(pVfs, zOal, 0);
sqlite3_free(zOal);
}
}
/*
** Allocate a private rbu VFS for the rbu handle passed as the only
** argument. This VFS will be used unless the call to sqlite3rbu_open()
** specified a URI with a vfs=? option in place of a target database
** file name.
*/
static void rbuCreateVfs(sqlite3rbu *p){
int rnd;
char zRnd[64];
assert( p->rc==SQLITE_OK );
sqlite3_randomness(sizeof(int), (void*)&rnd);
sqlite3_snprintf(sizeof(zRnd), zRnd, "rbu_vfs_%d", rnd);
p->rc = sqlite3rbu_create_vfs(zRnd, 0);
if( p->rc==SQLITE_OK ){
sqlite3_vfs *pVfs = sqlite3_vfs_find(zRnd);
assert( pVfs );
p->zVfsName = pVfs->zName;
}
}
/*
** Destroy the private VFS created for the rbu handle passed as the only
** argument by an earlier call to rbuCreateVfs().
*/
static void rbuDeleteVfs(sqlite3rbu *p){
if( p->zVfsName ){
sqlite3rbu_destroy_vfs(p->zVfsName);
p->zVfsName = 0;
}
}
/*
** Open and return a new RBU handle.
*/
sqlite3rbu *sqlite3rbu_open(
const char *zTarget,
const char *zRbu,
const char *zState
){
sqlite3rbu *p;
int nTarget = strlen(zTarget);
int nRbu = strlen(zRbu);
int nState = zState ? strlen(zState) : 0;
p = (sqlite3rbu*)sqlite3_malloc(sizeof(sqlite3rbu)+nTarget+1+nRbu+1+nState+1);
if( p ){
RbuState *pState = 0;
/* Create the custom VFS. */
memset(p, 0, sizeof(sqlite3rbu));
rbuCreateVfs(p);
/* Open the target database */
if( p->rc==SQLITE_OK ){
p->zTarget = (char*)&p[1];
memcpy(p->zTarget, zTarget, nTarget+1);
p->zRbu = &p->zTarget[nTarget+1];
memcpy(p->zRbu, zRbu, nRbu+1);
if( zState ){
p->zState = &p->zRbu[nRbu+1];
memcpy(p->zState, zState, nState+1);
}
rbuOpenDatabase(p);
}
/* If it has not already been created, create the rbu_state table */
rbuMPrintfExec(p, p->dbRbu, RBU_CREATE_STATE, p->zStateDb);
if( p->rc==SQLITE_OK ){
pState = rbuLoadState(p);
assert( pState || p->rc!=SQLITE_OK );
if( p->rc==SQLITE_OK ){
if( pState->eStage==0 ){
rbuDeleteOalFile(p);
p->eStage = RBU_STAGE_OAL;
}else{
p->eStage = pState->eStage;
}
p->nProgress = pState->nProgress;
p->iOalSz = pState->iOalSz;
}
}
assert( p->rc!=SQLITE_OK || p->eStage!=0 );
if( p->rc==SQLITE_OK && p->pTargetFd->pWalFd ){
if( p->eStage==RBU_STAGE_OAL ){
p->rc = SQLITE_ERROR;
p->zErrmsg = sqlite3_mprintf("cannot update wal mode database");
}else if( p->eStage==RBU_STAGE_MOVE ){
p->eStage = RBU_STAGE_CKPT;
p->nStep = 0;
}
}
if( p->rc==SQLITE_OK
&& (p->eStage==RBU_STAGE_OAL || p->eStage==RBU_STAGE_MOVE)
&& pState->eStage!=0 && p->pTargetFd->iCookie!=pState->iCookie
){
/* At this point (pTargetFd->iCookie) contains the value of the
** change-counter cookie (the thing that gets incremented when a
** transaction is committed in rollback mode) currently stored on
** page 1 of the database file. */
p->rc = SQLITE_BUSY;
p->zErrmsg = sqlite3_mprintf("database modified during rbu update");
}
if( p->rc==SQLITE_OK ){
if( p->eStage==RBU_STAGE_OAL ){
sqlite3 *db = p->dbMain;
/* Open transactions both databases. The *-oal file is opened or
** created at this point. */
p->rc = sqlite3_exec(db, "BEGIN IMMEDIATE", 0, 0, &p->zErrmsg);
if( p->rc==SQLITE_OK ){
p->rc = sqlite3_exec(p->dbRbu, "BEGIN IMMEDIATE", 0, 0, &p->zErrmsg);
}
/* Check if the main database is a zipvfs db. If it is, set the upper
** level pager to use "journal_mode=off". This prevents it from
** generating a large journal using a temp file. */
if( p->rc==SQLITE_OK ){
int frc = sqlite3_file_control(db, "main", SQLITE_FCNTL_ZIPVFS, 0);
if( frc==SQLITE_OK ){
p->rc = sqlite3_exec(db, "PRAGMA journal_mode=off",0,0,&p->zErrmsg);
}
}
/* Point the object iterator at the first object */
if( p->rc==SQLITE_OK ){
p->rc = rbuObjIterFirst(p, &p->objiter);
}
/* If the RBU database contains no data_xxx tables, declare the RBU
** update finished. */
if( p->rc==SQLITE_OK && p->objiter.zTbl==0 ){
p->rc = SQLITE_DONE;
}
if( p->rc==SQLITE_OK ){
rbuSetupOal(p, pState);
}
}else if( p->eStage==RBU_STAGE_MOVE ){
/* no-op */
}else if( p->eStage==RBU_STAGE_CKPT ){
rbuSetupCheckpoint(p, pState);
}else if( p->eStage==RBU_STAGE_DONE ){
p->rc = SQLITE_DONE;
}else{
p->rc = SQLITE_CORRUPT;
}
}
rbuFreeState(pState);
}
return p;
}
/*
** Return the database handle used by pRbu.
*/
sqlite3 *sqlite3rbu_db(sqlite3rbu *pRbu, int bRbu){
sqlite3 *db = 0;
if( pRbu ){
db = (bRbu ? pRbu->dbRbu : pRbu->dbMain);
}
return db;
}
/*
** If the error code currently stored in the RBU handle is SQLITE_CONSTRAINT,
** then edit any error message string so as to remove all occurrences of
** the pattern "rbu_imp_[0-9]*".
*/
static void rbuEditErrmsg(sqlite3rbu *p){
if( p->rc==SQLITE_CONSTRAINT && p->zErrmsg ){
int i;
int nErrmsg = strlen(p->zErrmsg);
for(i=0; i<(nErrmsg-8); i++){
if( memcmp(&p->zErrmsg[i], "rbu_imp_", 8)==0 ){
int nDel = 8;
while( p->zErrmsg[i+nDel]>='0' && p->zErrmsg[i+nDel]<='9' ) nDel++;
memmove(&p->zErrmsg[i], &p->zErrmsg[i+nDel], nErrmsg + 1 - i - nDel);
nErrmsg -= nDel;
}
}
}
}
/*
** Close the RBU handle.
*/
int sqlite3rbu_close(sqlite3rbu *p, char **pzErrmsg){
int rc;
if( p ){
/* Commit the transaction to the *-oal file. */
if( p->rc==SQLITE_OK && p->eStage==RBU_STAGE_OAL ){
p->rc = sqlite3_exec(p->dbMain, "COMMIT", 0, 0, &p->zErrmsg);
}
rbuSaveState(p, p->eStage);
if( p->rc==SQLITE_OK && p->eStage==RBU_STAGE_OAL ){
p->rc = sqlite3_exec(p->dbRbu, "COMMIT", 0, 0, &p->zErrmsg);
}
/* Close any open statement handles. */
rbuObjIterFinalize(&p->objiter);
/* Close the open database handle and VFS object. */
sqlite3_close(p->dbMain);
sqlite3_close(p->dbRbu);
rbuDeleteVfs(p);
sqlite3_free(p->aBuf);
sqlite3_free(p->aFrame);
rbuEditErrmsg(p);
rc = p->rc;
*pzErrmsg = p->zErrmsg;
sqlite3_free(p);
}else{
rc = SQLITE_NOMEM;
*pzErrmsg = 0;
}
return rc;
}
/*
** Return the total number of key-value operations (inserts, deletes or
** updates) that have been performed on the target database since the
** current RBU update was started.
*/
sqlite3_int64 sqlite3rbu_progress(sqlite3rbu *pRbu){
return pRbu->nProgress;
}
int sqlite3rbu_savestate(sqlite3rbu *p){
int rc = p->rc;
if( rc==SQLITE_DONE ) return SQLITE_OK;
assert( p->eStage>=RBU_STAGE_OAL && p->eStage<=RBU_STAGE_DONE );
if( p->eStage==RBU_STAGE_OAL ){
assert( rc!=SQLITE_DONE );
if( rc==SQLITE_OK ) rc = sqlite3_exec(p->dbMain, "COMMIT", 0, 0, 0);
}
p->rc = rc;
rbuSaveState(p, p->eStage);
rc = p->rc;
if( p->eStage==RBU_STAGE_OAL ){
assert( rc!=SQLITE_DONE );
if( rc==SQLITE_OK ) rc = sqlite3_exec(p->dbRbu, "COMMIT", 0, 0, 0);
if( rc==SQLITE_OK ) rc = sqlite3_exec(p->dbRbu, "BEGIN IMMEDIATE", 0, 0, 0);
if( rc==SQLITE_OK ) rc = sqlite3_exec(p->dbMain, "BEGIN IMMEDIATE", 0, 0,0);
}
p->rc = rc;
return rc;
}
/**************************************************************************
** Beginning of RBU VFS shim methods. The VFS shim modifies the behaviour
** of a standard VFS in the following ways:
**
** 1. Whenever the first page of a main database file is read or
** written, the value of the change-counter cookie is stored in
** rbu_file.iCookie. Similarly, the value of the "write-version"
** database header field is stored in rbu_file.iWriteVer. This ensures
** that the values are always trustworthy within an open transaction.
**
** 2. Whenever an SQLITE_OPEN_WAL file is opened, the (rbu_file.pWalFd)
** member variable of the associated database file descriptor is set
** to point to the new file. A mutex protected linked list of all main
** db fds opened using a particular RBU VFS is maintained at
** rbu_vfs.pMain to facilitate this.
**
** 3. Using a new file-control "SQLITE_FCNTL_RBU", a main db rbu_file
** object can be marked as the target database of an RBU update. This
** turns on the following extra special behaviour:
**
** 3a. If xAccess() is called to check if there exists a *-wal file
** associated with an RBU target database currently in RBU_STAGE_OAL
** stage (preparing the *-oal file), the following special handling
** applies:
**
** * if the *-wal file does exist, return SQLITE_CANTOPEN. An RBU
** target database may not be in wal mode already.
**
** * if the *-wal file does not exist, set the output parameter to
** non-zero (to tell SQLite that it does exist) anyway.
**
** Then, when xOpen() is called to open the *-wal file associated with
** the RBU target in RBU_STAGE_OAL stage, instead of opening the *-wal
** file, the rbu vfs opens the corresponding *-oal file instead.
**
** 3b. The *-shm pages returned by xShmMap() for a target db file in
** RBU_STAGE_OAL mode are actually stored in heap memory. This is to
** avoid creating a *-shm file on disk. Additionally, xShmLock() calls
** are no-ops on target database files in RBU_STAGE_OAL mode. This is
** because assert() statements in some VFS implementations fail if
** xShmLock() is called before xShmMap().
**
** 3c. If an EXCLUSIVE lock is attempted on a target database file in any
** mode except RBU_STAGE_DONE (all work completed and checkpointed), it
** fails with an SQLITE_BUSY error. This is to stop RBU connections
** from automatically checkpointing a *-wal (or *-oal) file from within
** sqlite3_close().
**
** 3d. In RBU_STAGE_CAPTURE mode, all xRead() calls on the wal file, and
** all xWrite() calls on the target database file perform no IO.
** Instead the frame and page numbers that would be read and written
** are recorded. Additionally, successful attempts to obtain exclusive
** xShmLock() WRITER, CHECKPOINTER and READ0 locks on the target
** database file are recorded. xShmLock() calls to unlock the same
** locks are no-ops (so that once obtained, these locks are never
** relinquished). Finally, calls to xSync() on the target database
** file fail with SQLITE_INTERNAL errors.
*/
static void rbuUnlockShm(rbu_file *p){
if( p->pRbu ){
int (*xShmLock)(sqlite3_file*,int,int,int) = p->pReal->pMethods->xShmLock;
int i;
for(i=0; i<SQLITE_SHM_NLOCK;i++){
if( (1<<i) & p->pRbu->mLock ){
xShmLock(p->pReal, i, 1, SQLITE_SHM_UNLOCK|SQLITE_SHM_EXCLUSIVE);
}
}
p->pRbu->mLock = 0;
}
}
/*
** Close an rbu file.
*/
static int rbuVfsClose(sqlite3_file *pFile){
rbu_file *p = (rbu_file*)pFile;
int rc;
int i;
/* Free the contents of the apShm[] array. And the array itself. */
for(i=0; i<p->nShm; i++){
sqlite3_free(p->apShm[i]);
}
sqlite3_free(p->apShm);
p->apShm = 0;
sqlite3_free(p->zDel);
if( p->openFlags & SQLITE_OPEN_MAIN_DB ){
rbu_file **pp;
sqlite3_mutex_enter(p->pRbuVfs->mutex);
for(pp=&p->pRbuVfs->pMain; *pp!=p; pp=&((*pp)->pMainNext));
*pp = p->pMainNext;
sqlite3_mutex_leave(p->pRbuVfs->mutex);
rbuUnlockShm(p);
p->pReal->pMethods->xShmUnmap(p->pReal, 0);
}
/* Close the underlying file handle */
rc = p->pReal->pMethods->xClose(p->pReal);
return rc;
}
/*
** Read and return an unsigned 32-bit big-endian integer from the buffer
** passed as the only argument.
*/
static u32 rbuGetU32(u8 *aBuf){
return ((u32)aBuf[0] << 24)
+ ((u32)aBuf[1] << 16)
+ ((u32)aBuf[2] << 8)
+ ((u32)aBuf[3]);
}
/*
** Read data from an rbuVfs-file.
*/
static int rbuVfsRead(
sqlite3_file *pFile,
void *zBuf,
int iAmt,
sqlite_int64 iOfst
){
rbu_file *p = (rbu_file*)pFile;
sqlite3rbu *pRbu = p->pRbu;
int rc;
if( pRbu && pRbu->eStage==RBU_STAGE_CAPTURE ){
assert( p->openFlags & SQLITE_OPEN_WAL );
rc = rbuCaptureWalRead(p->pRbu, iOfst, iAmt);
}else{
if( pRbu && pRbu->eStage==RBU_STAGE_OAL
&& (p->openFlags & SQLITE_OPEN_WAL)
&& iOfst>=pRbu->iOalSz
){
rc = SQLITE_OK;
memset(zBuf, 0, iAmt);
}else{
rc = p->pReal->pMethods->xRead(p->pReal, zBuf, iAmt, iOfst);
}
if( rc==SQLITE_OK && iOfst==0 && (p->openFlags & SQLITE_OPEN_MAIN_DB) ){
/* These look like magic numbers. But they are stable, as they are part
** of the definition of the SQLite file format, which may not change. */
u8 *pBuf = (u8*)zBuf;
p->iCookie = rbuGetU32(&pBuf[24]);
p->iWriteVer = pBuf[19];
}
}
return rc;
}
/*
** Write data to an rbuVfs-file.
*/
static int rbuVfsWrite(
sqlite3_file *pFile,
const void *zBuf,
int iAmt,
sqlite_int64 iOfst
){
rbu_file *p = (rbu_file*)pFile;
sqlite3rbu *pRbu = p->pRbu;
int rc;
if( pRbu && pRbu->eStage==RBU_STAGE_CAPTURE ){
assert( p->openFlags & SQLITE_OPEN_MAIN_DB );
rc = rbuCaptureDbWrite(p->pRbu, iOfst);
}else{
if( pRbu && pRbu->eStage==RBU_STAGE_OAL
&& (p->openFlags & SQLITE_OPEN_WAL)
&& iOfst>=pRbu->iOalSz
){
pRbu->iOalSz = iAmt + iOfst;
}
rc = p->pReal->pMethods->xWrite(p->pReal, zBuf, iAmt, iOfst);
if( rc==SQLITE_OK && iOfst==0 && (p->openFlags & SQLITE_OPEN_MAIN_DB) ){
/* These look like magic numbers. But they are stable, as they are part
** of the definition of the SQLite file format, which may not change. */
u8 *pBuf = (u8*)zBuf;
p->iCookie = rbuGetU32(&pBuf[24]);
p->iWriteVer = pBuf[19];
}
}
return rc;
}
/*
** Truncate an rbuVfs-file.
*/
static int rbuVfsTruncate(sqlite3_file *pFile, sqlite_int64 size){
rbu_file *p = (rbu_file*)pFile;
return p->pReal->pMethods->xTruncate(p->pReal, size);
}
/*
** Sync an rbuVfs-file.
*/
static int rbuVfsSync(sqlite3_file *pFile, int flags){
rbu_file *p = (rbu_file *)pFile;
if( p->pRbu && p->pRbu->eStage==RBU_STAGE_CAPTURE ){
if( p->openFlags & SQLITE_OPEN_MAIN_DB ){
return SQLITE_INTERNAL;
}
return SQLITE_OK;
}
return p->pReal->pMethods->xSync(p->pReal, flags);
}
/*
** Return the current file-size of an rbuVfs-file.
*/
static int rbuVfsFileSize(sqlite3_file *pFile, sqlite_int64 *pSize){
rbu_file *p = (rbu_file *)pFile;
return p->pReal->pMethods->xFileSize(p->pReal, pSize);
}
/*
** Lock an rbuVfs-file.
*/
static int rbuVfsLock(sqlite3_file *pFile, int eLock){
rbu_file *p = (rbu_file*)pFile;
sqlite3rbu *pRbu = p->pRbu;
int rc = SQLITE_OK;
assert( p->openFlags & (SQLITE_OPEN_MAIN_DB|SQLITE_OPEN_TEMP_DB) );
if( pRbu && eLock==SQLITE_LOCK_EXCLUSIVE && pRbu->eStage!=RBU_STAGE_DONE ){
/* Do not allow EXCLUSIVE locks. Preventing SQLite from taking this
** prevents it from checkpointing the database from sqlite3_close(). */
rc = SQLITE_BUSY;
}else{
rc = p->pReal->pMethods->xLock(p->pReal, eLock);
}
return rc;
}
/*
** Unlock an rbuVfs-file.
*/
static int rbuVfsUnlock(sqlite3_file *pFile, int eLock){
rbu_file *p = (rbu_file *)pFile;
return p->pReal->pMethods->xUnlock(p->pReal, eLock);
}
/*
** Check if another file-handle holds a RESERVED lock on an rbuVfs-file.
*/
static int rbuVfsCheckReservedLock(sqlite3_file *pFile, int *pResOut){
rbu_file *p = (rbu_file *)pFile;
return p->pReal->pMethods->xCheckReservedLock(p->pReal, pResOut);
}
/*
** File control method. For custom operations on an rbuVfs-file.
*/
static int rbuVfsFileControl(sqlite3_file *pFile, int op, void *pArg){
rbu_file *p = (rbu_file *)pFile;
int (*xControl)(sqlite3_file*,int,void*) = p->pReal->pMethods->xFileControl;
int rc;
assert( p->openFlags & (SQLITE_OPEN_MAIN_DB|SQLITE_OPEN_TEMP_DB)
|| p->openFlags & (SQLITE_OPEN_TRANSIENT_DB|SQLITE_OPEN_TEMP_JOURNAL)
);
if( op==SQLITE_FCNTL_RBU ){
sqlite3rbu *pRbu = (sqlite3rbu*)pArg;
/* First try to find another RBU vfs lower down in the vfs stack. If
** one is found, this vfs will operate in pass-through mode. The lower
** level vfs will do the special RBU handling. */
rc = xControl(p->pReal, op, pArg);
if( rc==SQLITE_NOTFOUND ){
/* Now search for a zipvfs instance lower down in the VFS stack. If
** one is found, this is an error. */
void *dummy = 0;
rc = xControl(p->pReal, SQLITE_FCNTL_ZIPVFS, &dummy);
if( rc==SQLITE_OK ){
rc = SQLITE_ERROR;
pRbu->zErrmsg = sqlite3_mprintf("rbu/zipvfs setup error");
}else if( rc==SQLITE_NOTFOUND ){
pRbu->pTargetFd = p;
p->pRbu = pRbu;
if( p->pWalFd ) p->pWalFd->pRbu = pRbu;
rc = SQLITE_OK;
}
}
return rc;
}
rc = xControl(p->pReal, op, pArg);
if( rc==SQLITE_OK && op==SQLITE_FCNTL_VFSNAME ){
rbu_vfs *pRbuVfs = p->pRbuVfs;
char *zIn = *(char**)pArg;
char *zOut = sqlite3_mprintf("rbu(%s)/%z", pRbuVfs->base.zName, zIn);
*(char**)pArg = zOut;
if( zOut==0 ) rc = SQLITE_NOMEM;
}
return rc;
}
/*
** Return the sector-size in bytes for an rbuVfs-file.
*/
static int rbuVfsSectorSize(sqlite3_file *pFile){
rbu_file *p = (rbu_file *)pFile;
return p->pReal->pMethods->xSectorSize(p->pReal);
}
/*
** Return the device characteristic flags supported by an rbuVfs-file.
*/
static int rbuVfsDeviceCharacteristics(sqlite3_file *pFile){
rbu_file *p = (rbu_file *)pFile;
return p->pReal->pMethods->xDeviceCharacteristics(p->pReal);
}
/*
** Take or release a shared-memory lock.
*/
static int rbuVfsShmLock(sqlite3_file *pFile, int ofst, int n, int flags){
rbu_file *p = (rbu_file*)pFile;
sqlite3rbu *pRbu = p->pRbu;
int rc = SQLITE_OK;
#ifdef SQLITE_AMALGAMATION
assert( WAL_CKPT_LOCK==1 );
#endif
assert( p->openFlags & (SQLITE_OPEN_MAIN_DB|SQLITE_OPEN_TEMP_DB) );
if( pRbu && (pRbu->eStage==RBU_STAGE_OAL || pRbu->eStage==RBU_STAGE_MOVE) ){
/* Magic number 1 is the WAL_CKPT_LOCK lock. Preventing SQLite from
** taking this lock also prevents any checkpoints from occurring.
** todo: really, it's not clear why this might occur, as
** wal_autocheckpoint ought to be turned off. */
if( ofst==WAL_LOCK_CKPT && n==1 ) rc = SQLITE_BUSY;
}else{
int bCapture = 0;
if( n==1 && (flags & SQLITE_SHM_EXCLUSIVE)
&& pRbu && pRbu->eStage==RBU_STAGE_CAPTURE
&& (ofst==WAL_LOCK_WRITE || ofst==WAL_LOCK_CKPT || ofst==WAL_LOCK_READ0)
){
bCapture = 1;
}
if( bCapture==0 || 0==(flags & SQLITE_SHM_UNLOCK) ){
rc = p->pReal->pMethods->xShmLock(p->pReal, ofst, n, flags);
if( bCapture && rc==SQLITE_OK ){
pRbu->mLock |= (1 << ofst);
}
}
}
return rc;
}
/*
** Obtain a pointer to a mapping of a single 32KiB page of the *-shm file.
*/
static int rbuVfsShmMap(
sqlite3_file *pFile,
int iRegion,
int szRegion,
int isWrite,
void volatile **pp
){
rbu_file *p = (rbu_file*)pFile;
int rc = SQLITE_OK;
int eStage = (p->pRbu ? p->pRbu->eStage : 0);
/* If not in RBU_STAGE_OAL, allow this call to pass through. Or, if this
** rbu is in the RBU_STAGE_OAL state, use heap memory for *-shm space
** instead of a file on disk. */
assert( p->openFlags & (SQLITE_OPEN_MAIN_DB|SQLITE_OPEN_TEMP_DB) );
if( eStage==RBU_STAGE_OAL || eStage==RBU_STAGE_MOVE ){
if( iRegion<=p->nShm ){
int nByte = (iRegion+1) * sizeof(char*);
char **apNew = (char**)sqlite3_realloc(p->apShm, nByte);
if( apNew==0 ){
rc = SQLITE_NOMEM;
}else{
memset(&apNew[p->nShm], 0, sizeof(char*) * (1 + iRegion - p->nShm));
p->apShm = apNew;
p->nShm = iRegion+1;
}
}
if( rc==SQLITE_OK && p->apShm[iRegion]==0 ){
char *pNew = (char*)sqlite3_malloc(szRegion);
if( pNew==0 ){
rc = SQLITE_NOMEM;
}else{
memset(pNew, 0, szRegion);
p->apShm[iRegion] = pNew;
}
}
if( rc==SQLITE_OK ){
*pp = p->apShm[iRegion];
}else{
*pp = 0;
}
}else{
assert( p->apShm==0 );
rc = p->pReal->pMethods->xShmMap(p->pReal, iRegion, szRegion, isWrite, pp);
}
return rc;
}
/*
** Memory barrier.
*/
static void rbuVfsShmBarrier(sqlite3_file *pFile){
rbu_file *p = (rbu_file *)pFile;
p->pReal->pMethods->xShmBarrier(p->pReal);
}
/*
** The xShmUnmap method.
*/
static int rbuVfsShmUnmap(sqlite3_file *pFile, int delFlag){
rbu_file *p = (rbu_file*)pFile;
int rc = SQLITE_OK;
int eStage = (p->pRbu ? p->pRbu->eStage : 0);
assert( p->openFlags & (SQLITE_OPEN_MAIN_DB|SQLITE_OPEN_TEMP_DB) );
if( eStage==RBU_STAGE_OAL || eStage==RBU_STAGE_MOVE ){
/* no-op */
}else{
/* Release the checkpointer and writer locks */
rbuUnlockShm(p);
rc = p->pReal->pMethods->xShmUnmap(p->pReal, delFlag);
}
return rc;
}
/*
** Given that zWal points to a buffer containing a wal file name passed to
** either the xOpen() or xAccess() VFS method, return a pointer to the
** file-handle opened by the same database connection on the corresponding
** database file.
*/
static rbu_file *rbuFindMaindb(rbu_vfs *pRbuVfs, const char *zWal){
rbu_file *pDb;
sqlite3_mutex_enter(pRbuVfs->mutex);
for(pDb=pRbuVfs->pMain; pDb && pDb->zWal!=zWal; pDb=pDb->pMainNext);
sqlite3_mutex_leave(pRbuVfs->mutex);
return pDb;
}
/*
** Open an rbu file handle.
*/
static int rbuVfsOpen(
sqlite3_vfs *pVfs,
const char *zName,
sqlite3_file *pFile,
int flags,
int *pOutFlags
){
static sqlite3_io_methods rbuvfs_io_methods = {
2, /* iVersion */
rbuVfsClose, /* xClose */
rbuVfsRead, /* xRead */
rbuVfsWrite, /* xWrite */
rbuVfsTruncate, /* xTruncate */
rbuVfsSync, /* xSync */
rbuVfsFileSize, /* xFileSize */
rbuVfsLock, /* xLock */
rbuVfsUnlock, /* xUnlock */
rbuVfsCheckReservedLock, /* xCheckReservedLock */
rbuVfsFileControl, /* xFileControl */
rbuVfsSectorSize, /* xSectorSize */
rbuVfsDeviceCharacteristics, /* xDeviceCharacteristics */
rbuVfsShmMap, /* xShmMap */
rbuVfsShmLock, /* xShmLock */
rbuVfsShmBarrier, /* xShmBarrier */
rbuVfsShmUnmap, /* xShmUnmap */
0, 0 /* xFetch, xUnfetch */
};
rbu_vfs *pRbuVfs = (rbu_vfs*)pVfs;
sqlite3_vfs *pRealVfs = pRbuVfs->pRealVfs;
rbu_file *pFd = (rbu_file *)pFile;
int rc = SQLITE_OK;
const char *zOpen = zName;
memset(pFd, 0, sizeof(rbu_file));
pFd->pReal = (sqlite3_file*)&pFd[1];
pFd->pRbuVfs = pRbuVfs;
pFd->openFlags = flags;
if( zName ){
if( flags & SQLITE_OPEN_MAIN_DB ){
/* A main database has just been opened. The following block sets
** (pFd->zWal) to point to a buffer owned by SQLite that contains
** the name of the *-wal file this db connection will use. SQLite
** happens to pass a pointer to this buffer when using xAccess()
** or xOpen() to operate on the *-wal file. */
int n = strlen(zName);
const char *z = &zName[n];
if( flags & SQLITE_OPEN_URI ){
int odd = 0;
while( 1 ){
if( z[0]==0 ){
odd = 1 - odd;
if( odd && z[1]==0 ) break;
}
z++;
}
z += 2;
}else{
while( *z==0 ) z++;
}
z += (n + 8 + 1);
pFd->zWal = z;
}
else if( flags & SQLITE_OPEN_WAL ){
rbu_file *pDb = rbuFindMaindb(pRbuVfs, zName);
if( pDb ){
if( pDb->pRbu && pDb->pRbu->eStage==RBU_STAGE_OAL ){
/* This call is to open a *-wal file. Intead, open the *-oal. This
** code ensures that the string passed to xOpen() is terminated by a
** pair of '\0' bytes in case the VFS attempts to extract a URI
** parameter from it. */
int nCopy = strlen(zName);
char *zCopy = sqlite3_malloc(nCopy+2);
if( zCopy ){
memcpy(zCopy, zName, nCopy);
zCopy[nCopy-3] = 'o';
zCopy[nCopy] = '\0';
zCopy[nCopy+1] = '\0';
zOpen = (const char*)(pFd->zDel = zCopy);
}else{
rc = SQLITE_NOMEM;
}
pFd->pRbu = pDb->pRbu;
}
pDb->pWalFd = pFd;
}
}
}
if( rc==SQLITE_OK ){
rc = pRealVfs->xOpen(pRealVfs, zOpen, pFd->pReal, flags, pOutFlags);
}
if( pFd->pReal->pMethods ){
/* The xOpen() operation has succeeded. Set the sqlite3_file.pMethods
** pointer and, if the file is a main database file, link it into the
** mutex protected linked list of all such files. */
pFile->pMethods = &rbuvfs_io_methods;
if( flags & SQLITE_OPEN_MAIN_DB ){
sqlite3_mutex_enter(pRbuVfs->mutex);
pFd->pMainNext = pRbuVfs->pMain;
pRbuVfs->pMain = pFd;
sqlite3_mutex_leave(pRbuVfs->mutex);
}
}else{
sqlite3_free(pFd->zDel);
}
return rc;
}
/*
** Delete the file located at zPath.
*/
static int rbuVfsDelete(sqlite3_vfs *pVfs, const char *zPath, int dirSync){
sqlite3_vfs *pRealVfs = ((rbu_vfs*)pVfs)->pRealVfs;
return pRealVfs->xDelete(pRealVfs, zPath, dirSync);
}
/*
** Test for access permissions. Return true if the requested permission
** is available, or false otherwise.
*/
static int rbuVfsAccess(
sqlite3_vfs *pVfs,
const char *zPath,
int flags,
int *pResOut
){
rbu_vfs *pRbuVfs = (rbu_vfs*)pVfs;
sqlite3_vfs *pRealVfs = pRbuVfs->pRealVfs;
int rc;
rc = pRealVfs->xAccess(pRealVfs, zPath, flags, pResOut);
/* If this call is to check if a *-wal file associated with an RBU target
** database connection exists, and the RBU update is in RBU_STAGE_OAL,
** the following special handling is activated:
**
** a) if the *-wal file does exist, return SQLITE_CANTOPEN. This
** ensures that the RBU extension never tries to update a database
** in wal mode, even if the first page of the database file has
** been damaged.
**
** b) if the *-wal file does not exist, claim that it does anyway,
** causing SQLite to call xOpen() to open it. This call will also
** be intercepted (see the rbuVfsOpen() function) and the *-oal
** file opened instead.
*/
if( rc==SQLITE_OK && flags==SQLITE_ACCESS_EXISTS ){
rbu_file *pDb = rbuFindMaindb(pRbuVfs, zPath);
if( pDb && pDb->pRbu && pDb->pRbu->eStage==RBU_STAGE_OAL ){
if( *pResOut ){
rc = SQLITE_CANTOPEN;
}else{
*pResOut = 1;
}
}
}
return rc;
}
/*
** Populate buffer zOut with the full canonical pathname corresponding
** to the pathname in zPath. zOut is guaranteed to point to a buffer
** of at least (DEVSYM_MAX_PATHNAME+1) bytes.
*/
static int rbuVfsFullPathname(
sqlite3_vfs *pVfs,
const char *zPath,
int nOut,
char *zOut
){
sqlite3_vfs *pRealVfs = ((rbu_vfs*)pVfs)->pRealVfs;
return pRealVfs->xFullPathname(pRealVfs, zPath, nOut, zOut);
}
#ifndef SQLITE_OMIT_LOAD_EXTENSION
/*
** Open the dynamic library located at zPath and return a handle.
*/
static void *rbuVfsDlOpen(sqlite3_vfs *pVfs, const char *zPath){
sqlite3_vfs *pRealVfs = ((rbu_vfs*)pVfs)->pRealVfs;
return pRealVfs->xDlOpen(pRealVfs, zPath);
}
/*
** Populate the buffer zErrMsg (size nByte bytes) with a human readable
** utf-8 string describing the most recent error encountered associated
** with dynamic libraries.
*/
static void rbuVfsDlError(sqlite3_vfs *pVfs, int nByte, char *zErrMsg){
sqlite3_vfs *pRealVfs = ((rbu_vfs*)pVfs)->pRealVfs;
pRealVfs->xDlError(pRealVfs, nByte, zErrMsg);
}
/*
** Return a pointer to the symbol zSymbol in the dynamic library pHandle.
*/
static void (*rbuVfsDlSym(
sqlite3_vfs *pVfs,
void *pArg,
const char *zSym
))(void){
sqlite3_vfs *pRealVfs = ((rbu_vfs*)pVfs)->pRealVfs;
return pRealVfs->xDlSym(pRealVfs, pArg, zSym);
}
/*
** Close the dynamic library handle pHandle.
*/
static void rbuVfsDlClose(sqlite3_vfs *pVfs, void *pHandle){
sqlite3_vfs *pRealVfs = ((rbu_vfs*)pVfs)->pRealVfs;
pRealVfs->xDlClose(pRealVfs, pHandle);
}
#endif /* SQLITE_OMIT_LOAD_EXTENSION */
/*
** Populate the buffer pointed to by zBufOut with nByte bytes of
** random data.
*/
static int rbuVfsRandomness(sqlite3_vfs *pVfs, int nByte, char *zBufOut){
sqlite3_vfs *pRealVfs = ((rbu_vfs*)pVfs)->pRealVfs;
return pRealVfs->xRandomness(pRealVfs, nByte, zBufOut);
}
/*
** Sleep for nMicro microseconds. Return the number of microseconds
** actually slept.
*/
static int rbuVfsSleep(sqlite3_vfs *pVfs, int nMicro){
sqlite3_vfs *pRealVfs = ((rbu_vfs*)pVfs)->pRealVfs;
return pRealVfs->xSleep(pRealVfs, nMicro);
}
/*
** Return the current time as a Julian Day number in *pTimeOut.
*/
static int rbuVfsCurrentTime(sqlite3_vfs *pVfs, double *pTimeOut){
sqlite3_vfs *pRealVfs = ((rbu_vfs*)pVfs)->pRealVfs;
return pRealVfs->xCurrentTime(pRealVfs, pTimeOut);
}
/*
** No-op.
*/
static int rbuVfsGetLastError(sqlite3_vfs *pVfs, int a, char *b){
return 0;
}
/*
** Deregister and destroy an RBU vfs created by an earlier call to
** sqlite3rbu_create_vfs().
*/
void sqlite3rbu_destroy_vfs(const char *zName){
sqlite3_vfs *pVfs = sqlite3_vfs_find(zName);
if( pVfs && pVfs->xOpen==rbuVfsOpen ){
sqlite3_mutex_free(((rbu_vfs*)pVfs)->mutex);
sqlite3_vfs_unregister(pVfs);
sqlite3_free(pVfs);
}
}
/*
** Create an RBU VFS named zName that accesses the underlying file-system
** via existing VFS zParent. The new object is registered as a non-default
** VFS with SQLite before returning.
*/
int sqlite3rbu_create_vfs(const char *zName, const char *zParent){
/* Template for VFS */
static sqlite3_vfs vfs_template = {
1, /* iVersion */
0, /* szOsFile */
0, /* mxPathname */
0, /* pNext */
0, /* zName */
0, /* pAppData */
rbuVfsOpen, /* xOpen */
rbuVfsDelete, /* xDelete */
rbuVfsAccess, /* xAccess */
rbuVfsFullPathname, /* xFullPathname */
#ifndef SQLITE_OMIT_LOAD_EXTENSION
rbuVfsDlOpen, /* xDlOpen */
rbuVfsDlError, /* xDlError */
rbuVfsDlSym, /* xDlSym */
rbuVfsDlClose, /* xDlClose */
#else
0, 0, 0, 0,
#endif
rbuVfsRandomness, /* xRandomness */
rbuVfsSleep, /* xSleep */
rbuVfsCurrentTime, /* xCurrentTime */
rbuVfsGetLastError, /* xGetLastError */
0, /* xCurrentTimeInt64 (version 2) */
0, 0, 0 /* Unimplemented version 3 methods */
};
rbu_vfs *pNew = 0; /* Newly allocated VFS */
int nName;
int rc = SQLITE_OK;
int nByte;
nName = strlen(zName);
nByte = sizeof(rbu_vfs) + nName + 1;
pNew = (rbu_vfs*)sqlite3_malloc(nByte);
if( pNew==0 ){
rc = SQLITE_NOMEM;
}else{
sqlite3_vfs *pParent; /* Parent VFS */
memset(pNew, 0, nByte);
pParent = sqlite3_vfs_find(zParent);
if( pParent==0 ){
rc = SQLITE_NOTFOUND;
}else{
char *zSpace;
memcpy(&pNew->base, &vfs_template, sizeof(sqlite3_vfs));
pNew->base.mxPathname = pParent->mxPathname;
pNew->base.szOsFile = sizeof(rbu_file) + pParent->szOsFile;
pNew->pRealVfs = pParent;
pNew->base.zName = (const char*)(zSpace = (char*)&pNew[1]);
memcpy(zSpace, zName, nName);
/* Allocate the mutex and register the new VFS (not as the default) */
pNew->mutex = sqlite3_mutex_alloc(SQLITE_MUTEX_RECURSIVE);
if( pNew->mutex==0 ){
rc = SQLITE_NOMEM;
}else{
rc = sqlite3_vfs_register(&pNew->base, 0);
}
}
if( rc!=SQLITE_OK ){
sqlite3_mutex_free(pNew->mutex);
sqlite3_free(pNew);
}
}
return rc;
}
/**************************************************************************/
#endif /* !defined(SQLITE_CORE) || defined(SQLITE_ENABLE_RBU) */