| |
| #if defined(SQLITE_ENABLE_SESSION) && defined(SQLITE_ENABLE_PREUPDATE_HOOK) |
| #include "sqlite3session.h" |
| #include <assert.h> |
| #include <string.h> |
| |
| #ifndef SQLITE_AMALGAMATION |
| # include "sqliteInt.h" |
| # include "vdbeInt.h" |
| #endif |
| |
| typedef struct SessionTable SessionTable; |
| typedef struct SessionChange SessionChange; |
| typedef struct SessionBuffer SessionBuffer; |
| typedef struct SessionInput SessionInput; |
| |
| /* |
| ** Minimum chunk size used by streaming versions of functions. |
| */ |
| #ifndef SESSIONS_STRM_CHUNK_SIZE |
| # ifdef SQLITE_TEST |
| # define SESSIONS_STRM_CHUNK_SIZE 64 |
| # else |
| # define SESSIONS_STRM_CHUNK_SIZE 1024 |
| # endif |
| #endif |
| |
| #define SESSIONS_ROWID "_rowid_" |
| |
| static int sessions_strm_chunk_size = SESSIONS_STRM_CHUNK_SIZE; |
| |
| typedef struct SessionHook SessionHook; |
| struct SessionHook { |
| void *pCtx; |
| int (*xOld)(void*,int,sqlite3_value**); |
| int (*xNew)(void*,int,sqlite3_value**); |
| int (*xCount)(void*); |
| int (*xDepth)(void*); |
| }; |
| |
| /* |
| ** Session handle structure. |
| */ |
| struct sqlite3_session { |
| sqlite3 *db; /* Database handle session is attached to */ |
| char *zDb; /* Name of database session is attached to */ |
| int bEnableSize; /* True if changeset_size() enabled */ |
| int bEnable; /* True if currently recording */ |
| int bIndirect; /* True if all changes are indirect */ |
| int bAutoAttach; /* True to auto-attach tables */ |
| int bImplicitPK; /* True to handle tables with implicit PK */ |
| int rc; /* Non-zero if an error has occurred */ |
| void *pFilterCtx; /* First argument to pass to xTableFilter */ |
| int (*xTableFilter)(void *pCtx, const char *zTab); |
| i64 nMalloc; /* Number of bytes of data allocated */ |
| i64 nMaxChangesetSize; |
| sqlite3_value *pZeroBlob; /* Value containing X'' */ |
| sqlite3_session *pNext; /* Next session object on same db. */ |
| SessionTable *pTable; /* List of attached tables */ |
| SessionHook hook; /* APIs to grab new and old data with */ |
| }; |
| |
| /* |
| ** Instances of this structure are used to build strings or binary records. |
| */ |
| struct SessionBuffer { |
| u8 *aBuf; /* Pointer to changeset buffer */ |
| int nBuf; /* Size of buffer aBuf */ |
| int nAlloc; /* Size of allocation containing aBuf */ |
| }; |
| |
| /* |
| ** An object of this type is used internally as an abstraction for |
| ** input data. Input data may be supplied either as a single large buffer |
| ** (e.g. sqlite3changeset_start()) or using a stream function (e.g. |
| ** sqlite3changeset_start_strm()). |
| */ |
| struct SessionInput { |
| int bNoDiscard; /* If true, do not discard in InputBuffer() */ |
| int iCurrent; /* Offset in aData[] of current change */ |
| int iNext; /* Offset in aData[] of next change */ |
| u8 *aData; /* Pointer to buffer containing changeset */ |
| int nData; /* Number of bytes in aData */ |
| |
| SessionBuffer buf; /* Current read buffer */ |
| int (*xInput)(void*, void*, int*); /* Input stream call (or NULL) */ |
| void *pIn; /* First argument to xInput */ |
| int bEof; /* Set to true after xInput finished */ |
| }; |
| |
| /* |
| ** Structure for changeset iterators. |
| */ |
| struct sqlite3_changeset_iter { |
| SessionInput in; /* Input buffer or stream */ |
| SessionBuffer tblhdr; /* Buffer to hold apValue/zTab/abPK/ */ |
| int bPatchset; /* True if this is a patchset */ |
| int bInvert; /* True to invert changeset */ |
| int bSkipEmpty; /* Skip noop UPDATE changes */ |
| int rc; /* Iterator error code */ |
| sqlite3_stmt *pConflict; /* Points to conflicting row, if any */ |
| char *zTab; /* Current table */ |
| int nCol; /* Number of columns in zTab */ |
| int op; /* Current operation */ |
| int bIndirect; /* True if current change was indirect */ |
| u8 *abPK; /* Primary key array */ |
| sqlite3_value **apValue; /* old.* and new.* values */ |
| }; |
| |
| /* |
| ** Each session object maintains a set of the following structures, one |
| ** for each table the session object is monitoring. The structures are |
| ** stored in a linked list starting at sqlite3_session.pTable. |
| ** |
| ** The keys of the SessionTable.aChange[] hash table are all rows that have |
| ** been modified in any way since the session object was attached to the |
| ** table. |
| ** |
| ** The data associated with each hash-table entry is a structure containing |
| ** a subset of the initial values that the modified row contained at the |
| ** start of the session. Or no initial values if the row was inserted. |
| ** |
| ** pDfltStmt: |
| ** This is only used by the sqlite3changegroup_xxx() APIs, not by |
| ** regular sqlite3_session objects. It is a SELECT statement that |
| ** selects the default value for each table column. For example, |
| ** if the table is |
| ** |
| ** CREATE TABLE xx(a DEFAULT 1, b, c DEFAULT 'abc') |
| ** |
| ** then this variable is the compiled version of: |
| ** |
| ** SELECT 1, NULL, 'abc' |
| */ |
| struct SessionTable { |
| SessionTable *pNext; |
| char *zName; /* Local name of table */ |
| int nCol; /* Number of columns in table zName */ |
| int bStat1; /* True if this is sqlite_stat1 */ |
| int bRowid; /* True if this table uses rowid for PK */ |
| const char **azCol; /* Column names */ |
| const char **azDflt; /* Default value expressions */ |
| u8 *abPK; /* Array of primary key flags */ |
| int nEntry; /* Total number of entries in hash table */ |
| int nChange; /* Size of apChange[] array */ |
| SessionChange **apChange; /* Hash table buckets */ |
| sqlite3_stmt *pDfltStmt; |
| }; |
| |
| /* |
| ** RECORD FORMAT: |
| ** |
| ** The following record format is similar to (but not compatible with) that |
| ** used in SQLite database files. This format is used as part of the |
| ** change-set binary format, and so must be architecture independent. |
| ** |
| ** Unlike the SQLite database record format, each field is self-contained - |
| ** there is no separation of header and data. Each field begins with a |
| ** single byte describing its type, as follows: |
| ** |
| ** 0x00: Undefined value. |
| ** 0x01: Integer value. |
| ** 0x02: Real value. |
| ** 0x03: Text value. |
| ** 0x04: Blob value. |
| ** 0x05: SQL NULL value. |
| ** |
| ** Note that the above match the definitions of SQLITE_INTEGER, SQLITE_TEXT |
| ** and so on in sqlite3.h. For undefined and NULL values, the field consists |
| ** only of the single type byte. For other types of values, the type byte |
| ** is followed by: |
| ** |
| ** Text values: |
| ** A varint containing the number of bytes in the value (encoded using |
| ** UTF-8). Followed by a buffer containing the UTF-8 representation |
| ** of the text value. There is no nul terminator. |
| ** |
| ** Blob values: |
| ** A varint containing the number of bytes in the value, followed by |
| ** a buffer containing the value itself. |
| ** |
| ** Integer values: |
| ** An 8-byte big-endian integer value. |
| ** |
| ** Real values: |
| ** An 8-byte big-endian IEEE 754-2008 real value. |
| ** |
| ** Varint values are encoded in the same way as varints in the SQLite |
| ** record format. |
| ** |
| ** CHANGESET FORMAT: |
| ** |
| ** A changeset is a collection of DELETE, UPDATE and INSERT operations on |
| ** one or more tables. Operations on a single table are grouped together, |
| ** but may occur in any order (i.e. deletes, updates and inserts are all |
| ** mixed together). |
| ** |
| ** Each group of changes begins with a table header: |
| ** |
| ** 1 byte: Constant 0x54 (capital 'T') |
| ** Varint: Number of columns in the table. |
| ** nCol bytes: 0x01 for PK columns, 0x00 otherwise. |
| ** N bytes: Unqualified table name (encoded using UTF-8). Nul-terminated. |
| ** |
| ** Followed by one or more changes to the table. |
| ** |
| ** 1 byte: Either SQLITE_INSERT (0x12), UPDATE (0x17) or DELETE (0x09). |
| ** 1 byte: The "indirect-change" flag. |
| ** old.* record: (delete and update only) |
| ** new.* record: (insert and update only) |
| ** |
| ** The "old.*" and "new.*" records, if present, are N field records in the |
| ** format described above under "RECORD FORMAT", where N is the number of |
| ** columns in the table. The i'th field of each record is associated with |
| ** the i'th column of the table, counting from left to right in the order |
| ** in which columns were declared in the CREATE TABLE statement. |
| ** |
| ** The new.* record that is part of each INSERT change contains the values |
| ** that make up the new row. Similarly, the old.* record that is part of each |
| ** DELETE change contains the values that made up the row that was deleted |
| ** from the database. In the changeset format, the records that are part |
| ** of INSERT or DELETE changes never contain any undefined (type byte 0x00) |
| ** fields. |
| ** |
| ** Within the old.* record associated with an UPDATE change, all fields |
| ** associated with table columns that are not PRIMARY KEY columns and are |
| ** not modified by the UPDATE change are set to "undefined". Other fields |
| ** are set to the values that made up the row before the UPDATE that the |
| ** change records took place. Within the new.* record, fields associated |
| ** with table columns modified by the UPDATE change contain the new |
| ** values. Fields associated with table columns that are not modified |
| ** are set to "undefined". |
| ** |
| ** PATCHSET FORMAT: |
| ** |
| ** A patchset is also a collection of changes. It is similar to a changeset, |
| ** but leaves undefined those fields that are not useful if no conflict |
| ** resolution is required when applying the changeset. |
| ** |
| ** Each group of changes begins with a table header: |
| ** |
| ** 1 byte: Constant 0x50 (capital 'P') |
| ** Varint: Number of columns in the table. |
| ** nCol bytes: 0x01 for PK columns, 0x00 otherwise. |
| ** N bytes: Unqualified table name (encoded using UTF-8). Nul-terminated. |
| ** |
| ** Followed by one or more changes to the table. |
| ** |
| ** 1 byte: Either SQLITE_INSERT (0x12), UPDATE (0x17) or DELETE (0x09). |
| ** 1 byte: The "indirect-change" flag. |
| ** single record: (PK fields for DELETE, PK and modified fields for UPDATE, |
| ** full record for INSERT). |
| ** |
| ** As in the changeset format, each field of the single record that is part |
| ** of a patchset change is associated with the correspondingly positioned |
| ** table column, counting from left to right within the CREATE TABLE |
| ** statement. |
| ** |
| ** For a DELETE change, all fields within the record except those associated |
| ** with PRIMARY KEY columns are omitted. The PRIMARY KEY fields contain the |
| ** values identifying the row to delete. |
| ** |
| ** For an UPDATE change, all fields except those associated with PRIMARY KEY |
| ** columns and columns that are modified by the UPDATE are set to "undefined". |
| ** PRIMARY KEY fields contain the values identifying the table row to update, |
| ** and fields associated with modified columns contain the new column values. |
| ** |
| ** The records associated with INSERT changes are in the same format as for |
| ** changesets. It is not possible for a record associated with an INSERT |
| ** change to contain a field set to "undefined". |
| ** |
| ** REBASE BLOB FORMAT: |
| ** |
| ** A rebase blob may be output by sqlite3changeset_apply_v2() and its |
| ** streaming equivalent for use with the sqlite3_rebaser APIs to rebase |
| ** existing changesets. A rebase blob contains one entry for each conflict |
| ** resolved using either the OMIT or REPLACE strategies within the apply_v2() |
| ** call. |
| ** |
| ** The format used for a rebase blob is very similar to that used for |
| ** changesets. All entries related to a single table are grouped together. |
| ** |
| ** Each group of entries begins with a table header in changeset format: |
| ** |
| ** 1 byte: Constant 0x54 (capital 'T') |
| ** Varint: Number of columns in the table. |
| ** nCol bytes: 0x01 for PK columns, 0x00 otherwise. |
| ** N bytes: Unqualified table name (encoded using UTF-8). Nul-terminated. |
| ** |
| ** Followed by one or more entries associated with the table. |
| ** |
| ** 1 byte: Either SQLITE_INSERT (0x12), DELETE (0x09). |
| ** 1 byte: Flag. 0x01 for REPLACE, 0x00 for OMIT. |
| ** record: (in the record format defined above). |
| ** |
| ** In a rebase blob, the first field is set to SQLITE_INSERT if the change |
| ** that caused the conflict was an INSERT or UPDATE, or to SQLITE_DELETE if |
| ** it was a DELETE. The second field is set to 0x01 if the conflict |
| ** resolution strategy was REPLACE, or 0x00 if it was OMIT. |
| ** |
| ** If the change that caused the conflict was a DELETE, then the single |
| ** record is a copy of the old.* record from the original changeset. If it |
| ** was an INSERT, then the single record is a copy of the new.* record. If |
| ** the conflicting change was an UPDATE, then the single record is a copy |
| ** of the new.* record with the PK fields filled in based on the original |
| ** old.* record. |
| */ |
| |
| /* |
| ** For each row modified during a session, there exists a single instance of |
| ** this structure stored in a SessionTable.aChange[] hash table. |
| */ |
| struct SessionChange { |
| u8 op; /* One of UPDATE, DELETE, INSERT */ |
| u8 bIndirect; /* True if this change is "indirect" */ |
| u16 nRecordField; /* Number of fields in aRecord[] */ |
| int nMaxSize; /* Max size of eventual changeset record */ |
| int nRecord; /* Number of bytes in buffer aRecord[] */ |
| u8 *aRecord; /* Buffer containing old.* record */ |
| SessionChange *pNext; /* For hash-table collisions */ |
| }; |
| |
| /* |
| ** Write a varint with value iVal into the buffer at aBuf. Return the |
| ** number of bytes written. |
| */ |
| static int sessionVarintPut(u8 *aBuf, int iVal){ |
| return putVarint32(aBuf, iVal); |
| } |
| |
| /* |
| ** Return the number of bytes required to store value iVal as a varint. |
| */ |
| static int sessionVarintLen(int iVal){ |
| return sqlite3VarintLen(iVal); |
| } |
| |
| /* |
| ** Read a varint value from aBuf[] into *piVal. Return the number of |
| ** bytes read. |
| */ |
| static int sessionVarintGet(const u8 *aBuf, int *piVal){ |
| return getVarint32(aBuf, *piVal); |
| } |
| |
| /* Load an unaligned and unsigned 32-bit integer */ |
| #define SESSION_UINT32(x) (((u32)(x)[0]<<24)|((x)[1]<<16)|((x)[2]<<8)|(x)[3]) |
| |
| /* |
| ** Read a 64-bit big-endian integer value from buffer aRec[]. Return |
| ** the value read. |
| */ |
| static sqlite3_int64 sessionGetI64(u8 *aRec){ |
| u64 x = SESSION_UINT32(aRec); |
| u32 y = SESSION_UINT32(aRec+4); |
| x = (x<<32) + y; |
| return (sqlite3_int64)x; |
| } |
| |
| /* |
| ** Write a 64-bit big-endian integer value to the buffer aBuf[]. |
| */ |
| static void sessionPutI64(u8 *aBuf, sqlite3_int64 i){ |
| aBuf[0] = (i>>56) & 0xFF; |
| aBuf[1] = (i>>48) & 0xFF; |
| aBuf[2] = (i>>40) & 0xFF; |
| aBuf[3] = (i>>32) & 0xFF; |
| aBuf[4] = (i>>24) & 0xFF; |
| aBuf[5] = (i>>16) & 0xFF; |
| aBuf[6] = (i>> 8) & 0xFF; |
| aBuf[7] = (i>> 0) & 0xFF; |
| } |
| |
| /* |
| ** This function is used to serialize the contents of value pValue (see |
| ** comment titled "RECORD FORMAT" above). |
| ** |
| ** If it is non-NULL, the serialized form of the value is written to |
| ** buffer aBuf. *pnWrite is set to the number of bytes written before |
| ** returning. Or, if aBuf is NULL, the only thing this function does is |
| ** set *pnWrite. |
| ** |
| ** If no error occurs, SQLITE_OK is returned. Or, if an OOM error occurs |
| ** within a call to sqlite3_value_text() (may fail if the db is utf-16)) |
| ** SQLITE_NOMEM is returned. |
| */ |
| static int sessionSerializeValue( |
| u8 *aBuf, /* If non-NULL, write serialized value here */ |
| sqlite3_value *pValue, /* Value to serialize */ |
| sqlite3_int64 *pnWrite /* IN/OUT: Increment by bytes written */ |
| ){ |
| int nByte; /* Size of serialized value in bytes */ |
| |
| if( pValue ){ |
| int eType; /* Value type (SQLITE_NULL, TEXT etc.) */ |
| |
| eType = sqlite3_value_type(pValue); |
| if( aBuf ) aBuf[0] = eType; |
| |
| switch( eType ){ |
| case SQLITE_NULL: |
| nByte = 1; |
| break; |
| |
| case SQLITE_INTEGER: |
| case SQLITE_FLOAT: |
| if( aBuf ){ |
| /* TODO: SQLite does something special to deal with mixed-endian |
| ** floating point values (e.g. ARM7). This code probably should |
| ** too. */ |
| u64 i; |
| if( eType==SQLITE_INTEGER ){ |
| i = (u64)sqlite3_value_int64(pValue); |
| }else{ |
| double r; |
| assert( sizeof(double)==8 && sizeof(u64)==8 ); |
| r = sqlite3_value_double(pValue); |
| memcpy(&i, &r, 8); |
| } |
| sessionPutI64(&aBuf[1], i); |
| } |
| nByte = 9; |
| break; |
| |
| default: { |
| u8 *z; |
| int n; |
| int nVarint; |
| |
| assert( eType==SQLITE_TEXT || eType==SQLITE_BLOB ); |
| if( eType==SQLITE_TEXT ){ |
| z = (u8 *)sqlite3_value_text(pValue); |
| }else{ |
| z = (u8 *)sqlite3_value_blob(pValue); |
| } |
| n = sqlite3_value_bytes(pValue); |
| if( z==0 && (eType!=SQLITE_BLOB || n>0) ) return SQLITE_NOMEM; |
| nVarint = sessionVarintLen(n); |
| |
| if( aBuf ){ |
| sessionVarintPut(&aBuf[1], n); |
| if( n>0 ) memcpy(&aBuf[nVarint + 1], z, n); |
| } |
| |
| nByte = 1 + nVarint + n; |
| break; |
| } |
| } |
| }else{ |
| nByte = 1; |
| if( aBuf ) aBuf[0] = '\0'; |
| } |
| |
| if( pnWrite ) *pnWrite += nByte; |
| return SQLITE_OK; |
| } |
| |
| /* |
| ** Allocate and return a pointer to a buffer nByte bytes in size. If |
| ** pSession is not NULL, increase the sqlite3_session.nMalloc variable |
| ** by the number of bytes allocated. |
| */ |
| static void *sessionMalloc64(sqlite3_session *pSession, i64 nByte){ |
| void *pRet = sqlite3_malloc64(nByte); |
| if( pSession ) pSession->nMalloc += sqlite3_msize(pRet); |
| return pRet; |
| } |
| |
| /* |
| ** Free buffer pFree, which must have been allocated by an earlier |
| ** call to sessionMalloc64(). If pSession is not NULL, decrease the |
| ** sqlite3_session.nMalloc counter by the number of bytes freed. |
| */ |
| static void sessionFree(sqlite3_session *pSession, void *pFree){ |
| if( pSession ) pSession->nMalloc -= sqlite3_msize(pFree); |
| sqlite3_free(pFree); |
| } |
| |
| /* |
| ** This macro is used to calculate hash key values for data structures. In |
| ** order to use this macro, the entire data structure must be represented |
| ** as a series of unsigned integers. In order to calculate a hash-key value |
| ** for a data structure represented as three such integers, the macro may |
| ** then be used as follows: |
| ** |
| ** int hash_key_value; |
| ** hash_key_value = HASH_APPEND(0, <value 1>); |
| ** hash_key_value = HASH_APPEND(hash_key_value, <value 2>); |
| ** hash_key_value = HASH_APPEND(hash_key_value, <value 3>); |
| ** |
| ** In practice, the data structures this macro is used for are the primary |
| ** key values of modified rows. |
| */ |
| #define HASH_APPEND(hash, add) ((hash) << 3) ^ (hash) ^ (unsigned int)(add) |
| |
| /* |
| ** Append the hash of the 64-bit integer passed as the second argument to the |
| ** hash-key value passed as the first. Return the new hash-key value. |
| */ |
| static unsigned int sessionHashAppendI64(unsigned int h, i64 i){ |
| h = HASH_APPEND(h, i & 0xFFFFFFFF); |
| return HASH_APPEND(h, (i>>32)&0xFFFFFFFF); |
| } |
| |
| /* |
| ** Append the hash of the blob passed via the second and third arguments to |
| ** the hash-key value passed as the first. Return the new hash-key value. |
| */ |
| static unsigned int sessionHashAppendBlob(unsigned int h, int n, const u8 *z){ |
| int i; |
| for(i=0; i<n; i++) h = HASH_APPEND(h, z[i]); |
| return h; |
| } |
| |
| /* |
| ** Append the hash of the data type passed as the second argument to the |
| ** hash-key value passed as the first. Return the new hash-key value. |
| */ |
| static unsigned int sessionHashAppendType(unsigned int h, int eType){ |
| return HASH_APPEND(h, eType); |
| } |
| |
| /* |
| ** This function may only be called from within a pre-update callback. |
| ** It calculates a hash based on the primary key values of the old.* or |
| ** new.* row currently available and, assuming no error occurs, writes it to |
| ** *piHash before returning. If the primary key contains one or more NULL |
| ** values, *pbNullPK is set to true before returning. |
| ** |
| ** If an error occurs, an SQLite error code is returned and the final values |
| ** of *piHash asn *pbNullPK are undefined. Otherwise, SQLITE_OK is returned |
| ** and the output variables are set as described above. |
| */ |
| static int sessionPreupdateHash( |
| sqlite3_session *pSession, /* Session object that owns pTab */ |
| i64 iRowid, |
| SessionTable *pTab, /* Session table handle */ |
| int bNew, /* True to hash the new.* PK */ |
| int *piHash, /* OUT: Hash value */ |
| int *pbNullPK /* OUT: True if there are NULL values in PK */ |
| ){ |
| unsigned int h = 0; /* Hash value to return */ |
| int i; /* Used to iterate through columns */ |
| |
| if( pTab->bRowid ){ |
| assert( pTab->nCol-1==pSession->hook.xCount(pSession->hook.pCtx) ); |
| h = sessionHashAppendI64(h, iRowid); |
| }else{ |
| assert( *pbNullPK==0 ); |
| assert( pTab->nCol==pSession->hook.xCount(pSession->hook.pCtx) ); |
| for(i=0; i<pTab->nCol; i++){ |
| if( pTab->abPK[i] ){ |
| int rc; |
| int eType; |
| sqlite3_value *pVal; |
| |
| if( bNew ){ |
| rc = pSession->hook.xNew(pSession->hook.pCtx, i, &pVal); |
| }else{ |
| rc = pSession->hook.xOld(pSession->hook.pCtx, i, &pVal); |
| } |
| if( rc!=SQLITE_OK ) return rc; |
| |
| eType = sqlite3_value_type(pVal); |
| h = sessionHashAppendType(h, eType); |
| if( eType==SQLITE_INTEGER || eType==SQLITE_FLOAT ){ |
| i64 iVal; |
| if( eType==SQLITE_INTEGER ){ |
| iVal = sqlite3_value_int64(pVal); |
| }else{ |
| double rVal = sqlite3_value_double(pVal); |
| assert( sizeof(iVal)==8 && sizeof(rVal)==8 ); |
| memcpy(&iVal, &rVal, 8); |
| } |
| h = sessionHashAppendI64(h, iVal); |
| }else if( eType==SQLITE_TEXT || eType==SQLITE_BLOB ){ |
| const u8 *z; |
| int n; |
| if( eType==SQLITE_TEXT ){ |
| z = (const u8 *)sqlite3_value_text(pVal); |
| }else{ |
| z = (const u8 *)sqlite3_value_blob(pVal); |
| } |
| n = sqlite3_value_bytes(pVal); |
| if( !z && (eType!=SQLITE_BLOB || n>0) ) return SQLITE_NOMEM; |
| h = sessionHashAppendBlob(h, n, z); |
| }else{ |
| assert( eType==SQLITE_NULL ); |
| assert( pTab->bStat1==0 || i!=1 ); |
| *pbNullPK = 1; |
| } |
| } |
| } |
| } |
| |
| *piHash = (h % pTab->nChange); |
| return SQLITE_OK; |
| } |
| |
| /* |
| ** The buffer that the argument points to contains a serialized SQL value. |
| ** Return the number of bytes of space occupied by the value (including |
| ** the type byte). |
| */ |
| static int sessionSerialLen(const u8 *a){ |
| int e; |
| int n; |
| assert( a!=0 ); |
| e = *a; |
| if( e==0 || e==0xFF ) return 1; |
| if( e==SQLITE_NULL ) return 1; |
| if( e==SQLITE_INTEGER || e==SQLITE_FLOAT ) return 9; |
| return sessionVarintGet(&a[1], &n) + 1 + n; |
| } |
| |
| /* |
| ** Based on the primary key values stored in change aRecord, calculate a |
| ** hash key. Assume the has table has nBucket buckets. The hash keys |
| ** calculated by this function are compatible with those calculated by |
| ** sessionPreupdateHash(). |
| ** |
| ** The bPkOnly argument is non-zero if the record at aRecord[] is from |
| ** a patchset DELETE. In this case the non-PK fields are omitted entirely. |
| */ |
| static unsigned int sessionChangeHash( |
| SessionTable *pTab, /* Table handle */ |
| int bPkOnly, /* Record consists of PK fields only */ |
| u8 *aRecord, /* Change record */ |
| int nBucket /* Assume this many buckets in hash table */ |
| ){ |
| unsigned int h = 0; /* Value to return */ |
| int i; /* Used to iterate through columns */ |
| u8 *a = aRecord; /* Used to iterate through change record */ |
| |
| for(i=0; i<pTab->nCol; i++){ |
| int eType = *a; |
| int isPK = pTab->abPK[i]; |
| if( bPkOnly && isPK==0 ) continue; |
| |
| /* It is not possible for eType to be SQLITE_NULL here. The session |
| ** module does not record changes for rows with NULL values stored in |
| ** primary key columns. */ |
| assert( eType==SQLITE_INTEGER || eType==SQLITE_FLOAT |
| || eType==SQLITE_TEXT || eType==SQLITE_BLOB |
| || eType==SQLITE_NULL || eType==0 |
| ); |
| assert( !isPK || (eType!=0 && eType!=SQLITE_NULL) ); |
| |
| if( isPK ){ |
| a++; |
| h = sessionHashAppendType(h, eType); |
| if( eType==SQLITE_INTEGER || eType==SQLITE_FLOAT ){ |
| h = sessionHashAppendI64(h, sessionGetI64(a)); |
| a += 8; |
| }else{ |
| int n; |
| a += sessionVarintGet(a, &n); |
| h = sessionHashAppendBlob(h, n, a); |
| a += n; |
| } |
| }else{ |
| a += sessionSerialLen(a); |
| } |
| } |
| return (h % nBucket); |
| } |
| |
| /* |
| ** Arguments aLeft and aRight are pointers to change records for table pTab. |
| ** This function returns true if the two records apply to the same row (i.e. |
| ** have the same values stored in the primary key columns), or false |
| ** otherwise. |
| */ |
| static int sessionChangeEqual( |
| SessionTable *pTab, /* Table used for PK definition */ |
| int bLeftPkOnly, /* True if aLeft[] contains PK fields only */ |
| u8 *aLeft, /* Change record */ |
| int bRightPkOnly, /* True if aRight[] contains PK fields only */ |
| u8 *aRight /* Change record */ |
| ){ |
| u8 *a1 = aLeft; /* Cursor to iterate through aLeft */ |
| u8 *a2 = aRight; /* Cursor to iterate through aRight */ |
| int iCol; /* Used to iterate through table columns */ |
| |
| for(iCol=0; iCol<pTab->nCol; iCol++){ |
| if( pTab->abPK[iCol] ){ |
| int n1 = sessionSerialLen(a1); |
| int n2 = sessionSerialLen(a2); |
| |
| if( n1!=n2 || memcmp(a1, a2, n1) ){ |
| return 0; |
| } |
| a1 += n1; |
| a2 += n2; |
| }else{ |
| if( bLeftPkOnly==0 ) a1 += sessionSerialLen(a1); |
| if( bRightPkOnly==0 ) a2 += sessionSerialLen(a2); |
| } |
| } |
| |
| return 1; |
| } |
| |
| /* |
| ** Arguments aLeft and aRight both point to buffers containing change |
| ** records with nCol columns. This function "merges" the two records into |
| ** a single records which is written to the buffer at *paOut. *paOut is |
| ** then set to point to one byte after the last byte written before |
| ** returning. |
| ** |
| ** The merging of records is done as follows: For each column, if the |
| ** aRight record contains a value for the column, copy the value from |
| ** their. Otherwise, if aLeft contains a value, copy it. If neither |
| ** record contains a value for a given column, then neither does the |
| ** output record. |
| */ |
| static void sessionMergeRecord( |
| u8 **paOut, |
| int nCol, |
| u8 *aLeft, |
| u8 *aRight |
| ){ |
| u8 *a1 = aLeft; /* Cursor used to iterate through aLeft */ |
| u8 *a2 = aRight; /* Cursor used to iterate through aRight */ |
| u8 *aOut = *paOut; /* Output cursor */ |
| int iCol; /* Used to iterate from 0 to nCol */ |
| |
| for(iCol=0; iCol<nCol; iCol++){ |
| int n1 = sessionSerialLen(a1); |
| int n2 = sessionSerialLen(a2); |
| if( *a2 ){ |
| memcpy(aOut, a2, n2); |
| aOut += n2; |
| }else{ |
| memcpy(aOut, a1, n1); |
| aOut += n1; |
| } |
| a1 += n1; |
| a2 += n2; |
| } |
| |
| *paOut = aOut; |
| } |
| |
| /* |
| ** This is a helper function used by sessionMergeUpdate(). |
| ** |
| ** When this function is called, both *paOne and *paTwo point to a value |
| ** within a change record. Before it returns, both have been advanced so |
| ** as to point to the next value in the record. |
| ** |
| ** If, when this function is called, *paTwo points to a valid value (i.e. |
| ** *paTwo[0] is not 0x00 - the "no value" placeholder), a copy of the *paTwo |
| ** pointer is returned and *pnVal is set to the number of bytes in the |
| ** serialized value. Otherwise, a copy of *paOne is returned and *pnVal |
| ** set to the number of bytes in the value at *paOne. If *paOne points |
| ** to the "no value" placeholder, *pnVal is set to 1. In other words: |
| ** |
| ** if( *paTwo is valid ) return *paTwo; |
| ** return *paOne; |
| ** |
| */ |
| static u8 *sessionMergeValue( |
| u8 **paOne, /* IN/OUT: Left-hand buffer pointer */ |
| u8 **paTwo, /* IN/OUT: Right-hand buffer pointer */ |
| int *pnVal /* OUT: Bytes in returned value */ |
| ){ |
| u8 *a1 = *paOne; |
| u8 *a2 = *paTwo; |
| u8 *pRet = 0; |
| int n1; |
| |
| assert( a1 ); |
| if( a2 ){ |
| int n2 = sessionSerialLen(a2); |
| if( *a2 ){ |
| *pnVal = n2; |
| pRet = a2; |
| } |
| *paTwo = &a2[n2]; |
| } |
| |
| n1 = sessionSerialLen(a1); |
| if( pRet==0 ){ |
| *pnVal = n1; |
| pRet = a1; |
| } |
| *paOne = &a1[n1]; |
| |
| return pRet; |
| } |
| |
| /* |
| ** This function is used by changeset_concat() to merge two UPDATE changes |
| ** on the same row. |
| */ |
| static int sessionMergeUpdate( |
| u8 **paOut, /* IN/OUT: Pointer to output buffer */ |
| SessionTable *pTab, /* Table change pertains to */ |
| int bPatchset, /* True if records are patchset records */ |
| u8 *aOldRecord1, /* old.* record for first change */ |
| u8 *aOldRecord2, /* old.* record for second change */ |
| u8 *aNewRecord1, /* new.* record for first change */ |
| u8 *aNewRecord2 /* new.* record for second change */ |
| ){ |
| u8 *aOld1 = aOldRecord1; |
| u8 *aOld2 = aOldRecord2; |
| u8 *aNew1 = aNewRecord1; |
| u8 *aNew2 = aNewRecord2; |
| |
| u8 *aOut = *paOut; |
| int i; |
| |
| if( bPatchset==0 ){ |
| int bRequired = 0; |
| |
| assert( aOldRecord1 && aNewRecord1 ); |
| |
| /* Write the old.* vector first. */ |
| for(i=0; i<pTab->nCol; i++){ |
| int nOld; |
| u8 *aOld; |
| int nNew; |
| u8 *aNew; |
| |
| aOld = sessionMergeValue(&aOld1, &aOld2, &nOld); |
| aNew = sessionMergeValue(&aNew1, &aNew2, &nNew); |
| if( pTab->abPK[i] || nOld!=nNew || memcmp(aOld, aNew, nNew) ){ |
| if( pTab->abPK[i]==0 ) bRequired = 1; |
| memcpy(aOut, aOld, nOld); |
| aOut += nOld; |
| }else{ |
| *(aOut++) = '\0'; |
| } |
| } |
| |
| if( !bRequired ) return 0; |
| } |
| |
| /* Write the new.* vector */ |
| aOld1 = aOldRecord1; |
| aOld2 = aOldRecord2; |
| aNew1 = aNewRecord1; |
| aNew2 = aNewRecord2; |
| for(i=0; i<pTab->nCol; i++){ |
| int nOld; |
| u8 *aOld; |
| int nNew; |
| u8 *aNew; |
| |
| aOld = sessionMergeValue(&aOld1, &aOld2, &nOld); |
| aNew = sessionMergeValue(&aNew1, &aNew2, &nNew); |
| if( bPatchset==0 |
| && (pTab->abPK[i] || (nOld==nNew && 0==memcmp(aOld, aNew, nNew))) |
| ){ |
| *(aOut++) = '\0'; |
| }else{ |
| memcpy(aOut, aNew, nNew); |
| aOut += nNew; |
| } |
| } |
| |
| *paOut = aOut; |
| return 1; |
| } |
| |
| /* |
| ** This function is only called from within a pre-update-hook callback. |
| ** It determines if the current pre-update-hook change affects the same row |
| ** as the change stored in argument pChange. If so, it returns true. Otherwise |
| ** if the pre-update-hook does not affect the same row as pChange, it returns |
| ** false. |
| */ |
| static int sessionPreupdateEqual( |
| sqlite3_session *pSession, /* Session object that owns SessionTable */ |
| i64 iRowid, /* Rowid value if pTab->bRowid */ |
| SessionTable *pTab, /* Table associated with change */ |
| SessionChange *pChange, /* Change to compare to */ |
| int op /* Current pre-update operation */ |
| ){ |
| int iCol; /* Used to iterate through columns */ |
| u8 *a = pChange->aRecord; /* Cursor used to scan change record */ |
| |
| if( pTab->bRowid ){ |
| if( a[0]!=SQLITE_INTEGER ) return 0; |
| return sessionGetI64(&a[1])==iRowid; |
| } |
| |
| assert( op==SQLITE_INSERT || op==SQLITE_UPDATE || op==SQLITE_DELETE ); |
| for(iCol=0; iCol<pTab->nCol; iCol++){ |
| if( !pTab->abPK[iCol] ){ |
| a += sessionSerialLen(a); |
| }else{ |
| sqlite3_value *pVal; /* Value returned by preupdate_new/old */ |
| int rc; /* Error code from preupdate_new/old */ |
| int eType = *a++; /* Type of value from change record */ |
| |
| /* The following calls to preupdate_new() and preupdate_old() can not |
| ** fail. This is because they cache their return values, and by the |
| ** time control flows to here they have already been called once from |
| ** within sessionPreupdateHash(). The first two asserts below verify |
| ** this (that the method has already been called). */ |
| if( op==SQLITE_INSERT ){ |
| /* assert( db->pPreUpdate->pNewUnpacked || db->pPreUpdate->aNew ); */ |
| rc = pSession->hook.xNew(pSession->hook.pCtx, iCol, &pVal); |
| }else{ |
| /* assert( db->pPreUpdate->pUnpacked ); */ |
| rc = pSession->hook.xOld(pSession->hook.pCtx, iCol, &pVal); |
| } |
| assert( rc==SQLITE_OK ); |
| (void)rc; /* Suppress warning about unused variable */ |
| if( sqlite3_value_type(pVal)!=eType ) return 0; |
| |
| /* A SessionChange object never has a NULL value in a PK column */ |
| assert( eType==SQLITE_INTEGER || eType==SQLITE_FLOAT |
| || eType==SQLITE_BLOB || eType==SQLITE_TEXT |
| ); |
| |
| if( eType==SQLITE_INTEGER || eType==SQLITE_FLOAT ){ |
| i64 iVal = sessionGetI64(a); |
| a += 8; |
| if( eType==SQLITE_INTEGER ){ |
| if( sqlite3_value_int64(pVal)!=iVal ) return 0; |
| }else{ |
| double rVal; |
| assert( sizeof(iVal)==8 && sizeof(rVal)==8 ); |
| memcpy(&rVal, &iVal, 8); |
| if( sqlite3_value_double(pVal)!=rVal ) return 0; |
| } |
| }else{ |
| int n; |
| const u8 *z; |
| a += sessionVarintGet(a, &n); |
| if( sqlite3_value_bytes(pVal)!=n ) return 0; |
| if( eType==SQLITE_TEXT ){ |
| z = sqlite3_value_text(pVal); |
| }else{ |
| z = sqlite3_value_blob(pVal); |
| } |
| if( n>0 && memcmp(a, z, n) ) return 0; |
| a += n; |
| } |
| } |
| } |
| |
| return 1; |
| } |
| |
| /* |
| ** If required, grow the hash table used to store changes on table pTab |
| ** (part of the session pSession). If a fatal OOM error occurs, set the |
| ** session object to failed and return SQLITE_ERROR. Otherwise, return |
| ** SQLITE_OK. |
| ** |
| ** It is possible that a non-fatal OOM error occurs in this function. In |
| ** that case the hash-table does not grow, but SQLITE_OK is returned anyway. |
| ** Growing the hash table in this case is a performance optimization only, |
| ** it is not required for correct operation. |
| */ |
| static int sessionGrowHash( |
| sqlite3_session *pSession, /* For memory accounting. May be NULL */ |
| int bPatchset, |
| SessionTable *pTab |
| ){ |
| if( pTab->nChange==0 || pTab->nEntry>=(pTab->nChange/2) ){ |
| int i; |
| SessionChange **apNew; |
| sqlite3_int64 nNew = 2*(sqlite3_int64)(pTab->nChange ? pTab->nChange : 128); |
| |
| apNew = (SessionChange**)sessionMalloc64( |
| pSession, sizeof(SessionChange*) * nNew |
| ); |
| if( apNew==0 ){ |
| if( pTab->nChange==0 ){ |
| return SQLITE_ERROR; |
| } |
| return SQLITE_OK; |
| } |
| memset(apNew, 0, sizeof(SessionChange *) * nNew); |
| |
| for(i=0; i<pTab->nChange; i++){ |
| SessionChange *p; |
| SessionChange *pNext; |
| for(p=pTab->apChange[i]; p; p=pNext){ |
| int bPkOnly = (p->op==SQLITE_DELETE && bPatchset); |
| int iHash = sessionChangeHash(pTab, bPkOnly, p->aRecord, nNew); |
| pNext = p->pNext; |
| p->pNext = apNew[iHash]; |
| apNew[iHash] = p; |
| } |
| } |
| |
| sessionFree(pSession, pTab->apChange); |
| pTab->nChange = nNew; |
| pTab->apChange = apNew; |
| } |
| |
| return SQLITE_OK; |
| } |
| |
| /* |
| ** This function queries the database for the names of the columns of table |
| ** zThis, in schema zDb. |
| ** |
| ** Otherwise, if they are not NULL, variable *pnCol is set to the number |
| ** of columns in the database table and variable *pzTab is set to point to a |
| ** nul-terminated copy of the table name. *pazCol (if not NULL) is set to |
| ** point to an array of pointers to column names. And *pabPK (again, if not |
| ** NULL) is set to point to an array of booleans - true if the corresponding |
| ** column is part of the primary key. |
| ** |
| ** For example, if the table is declared as: |
| ** |
| ** CREATE TABLE tbl1(w, x DEFAULT 'abc', y, z, PRIMARY KEY(w, z)); |
| ** |
| ** Then the five output variables are populated as follows: |
| ** |
| ** *pnCol = 4 |
| ** *pzTab = "tbl1" |
| ** *pazCol = {"w", "x", "y", "z"} |
| ** *pazDflt = {NULL, 'abc', NULL, NULL} |
| ** *pabPK = {1, 0, 0, 1} |
| ** |
| ** All returned buffers are part of the same single allocation, which must |
| ** be freed using sqlite3_free() by the caller |
| */ |
| static int sessionTableInfo( |
| sqlite3_session *pSession, /* For memory accounting. May be NULL */ |
| sqlite3 *db, /* Database connection */ |
| const char *zDb, /* Name of attached database (e.g. "main") */ |
| const char *zThis, /* Table name */ |
| int *pnCol, /* OUT: number of columns */ |
| const char **pzTab, /* OUT: Copy of zThis */ |
| const char ***pazCol, /* OUT: Array of column names for table */ |
| const char ***pazDflt, /* OUT: Array of default value expressions */ |
| u8 **pabPK, /* OUT: Array of booleans - true for PK col */ |
| int *pbRowid /* OUT: True if only PK is a rowid */ |
| ){ |
| char *zPragma; |
| sqlite3_stmt *pStmt; |
| int rc; |
| sqlite3_int64 nByte; |
| int nDbCol = 0; |
| int nThis; |
| int i; |
| u8 *pAlloc = 0; |
| char **azCol = 0; |
| char **azDflt = 0; |
| u8 *abPK = 0; |
| int bRowid = 0; /* Set to true to use rowid as PK */ |
| |
| assert( pazCol && pabPK ); |
| |
| *pazCol = 0; |
| *pabPK = 0; |
| *pnCol = 0; |
| if( pzTab ) *pzTab = 0; |
| if( pazDflt ) *pazDflt = 0; |
| |
| nThis = sqlite3Strlen30(zThis); |
| if( nThis==12 && 0==sqlite3_stricmp("sqlite_stat1", zThis) ){ |
| rc = sqlite3_table_column_metadata(db, zDb, zThis, 0, 0, 0, 0, 0, 0); |
| if( rc==SQLITE_OK ){ |
| /* For sqlite_stat1, pretend that (tbl,idx) is the PRIMARY KEY. */ |
| zPragma = sqlite3_mprintf( |
| "SELECT 0, 'tbl', '', 0, '', 1 UNION ALL " |
| "SELECT 1, 'idx', '', 0, '', 2 UNION ALL " |
| "SELECT 2, 'stat', '', 0, '', 0" |
| ); |
| }else if( rc==SQLITE_ERROR ){ |
| zPragma = sqlite3_mprintf(""); |
| }else{ |
| return rc; |
| } |
| }else{ |
| zPragma = sqlite3_mprintf("PRAGMA '%q'.table_info('%q')", zDb, zThis); |
| } |
| if( !zPragma ){ |
| return SQLITE_NOMEM; |
| } |
| |
| rc = sqlite3_prepare_v2(db, zPragma, -1, &pStmt, 0); |
| sqlite3_free(zPragma); |
| if( rc!=SQLITE_OK ){ |
| return rc; |
| } |
| |
| nByte = nThis + 1; |
| bRowid = (pbRowid!=0); |
| while( SQLITE_ROW==sqlite3_step(pStmt) ){ |
| nByte += sqlite3_column_bytes(pStmt, 1); /* name */ |
| nByte += sqlite3_column_bytes(pStmt, 4); /* dflt_value */ |
| nDbCol++; |
| if( sqlite3_column_int(pStmt, 5) ) bRowid = 0; /* pk */ |
| } |
| if( nDbCol==0 ) bRowid = 0; |
| nDbCol += bRowid; |
| nByte += strlen(SESSIONS_ROWID); |
| rc = sqlite3_reset(pStmt); |
| |
| if( rc==SQLITE_OK ){ |
| nByte += nDbCol * (sizeof(const char *)*2 + sizeof(u8) + 1 + 1); |
| pAlloc = sessionMalloc64(pSession, nByte); |
| if( pAlloc==0 ){ |
| rc = SQLITE_NOMEM; |
| }else{ |
| memset(pAlloc, 0, nByte); |
| } |
| } |
| if( rc==SQLITE_OK ){ |
| azCol = (char **)pAlloc; |
| azDflt = (char**)&azCol[nDbCol]; |
| pAlloc = (u8 *)&azDflt[nDbCol]; |
| abPK = (u8 *)pAlloc; |
| pAlloc = &abPK[nDbCol]; |
| if( pzTab ){ |
| memcpy(pAlloc, zThis, nThis+1); |
| *pzTab = (char *)pAlloc; |
| pAlloc += nThis+1; |
| } |
| |
| i = 0; |
| if( bRowid ){ |
| size_t nName = strlen(SESSIONS_ROWID); |
| memcpy(pAlloc, SESSIONS_ROWID, nName+1); |
| azCol[i] = (char*)pAlloc; |
| pAlloc += nName+1; |
| abPK[i] = 1; |
| i++; |
| } |
| while( SQLITE_ROW==sqlite3_step(pStmt) ){ |
| int nName = sqlite3_column_bytes(pStmt, 1); |
| int nDflt = sqlite3_column_bytes(pStmt, 4); |
| const unsigned char *zName = sqlite3_column_text(pStmt, 1); |
| const unsigned char *zDflt = sqlite3_column_text(pStmt, 4); |
| |
| if( zName==0 ) break; |
| memcpy(pAlloc, zName, nName+1); |
| azCol[i] = (char *)pAlloc; |
| pAlloc += nName+1; |
| if( zDflt ){ |
| memcpy(pAlloc, zDflt, nDflt+1); |
| azDflt[i] = (char *)pAlloc; |
| pAlloc += nDflt+1; |
| }else{ |
| azDflt[i] = 0; |
| } |
| abPK[i] = sqlite3_column_int(pStmt, 5); |
| i++; |
| } |
| rc = sqlite3_reset(pStmt); |
| } |
| |
| /* If successful, populate the output variables. Otherwise, zero them and |
| ** free any allocation made. An error code will be returned in this case. |
| */ |
| if( rc==SQLITE_OK ){ |
| *pazCol = (const char**)azCol; |
| if( pazDflt ) *pazDflt = (const char**)azDflt; |
| *pabPK = abPK; |
| *pnCol = nDbCol; |
| }else{ |
| sessionFree(pSession, azCol); |
| } |
| if( pbRowid ) *pbRowid = bRowid; |
| sqlite3_finalize(pStmt); |
| return rc; |
| } |
| |
| /* |
| ** This function is called to initialize the SessionTable.nCol, azCol[] |
| ** abPK[] and azDflt[] members of SessionTable object pTab. If these |
| ** fields are already initilialized, this function is a no-op. |
| ** |
| ** If an error occurs, an error code is stored in sqlite3_session.rc and |
| ** non-zero returned. Or, if no error occurs but the table has no primary |
| ** key, sqlite3_session.rc is left set to SQLITE_OK and non-zero returned to |
| ** indicate that updates on this table should be ignored. SessionTable.abPK |
| ** is set to NULL in this case. |
| */ |
| static int sessionInitTable( |
| sqlite3_session *pSession, /* Optional session handle */ |
| SessionTable *pTab, /* Table object to initialize */ |
| sqlite3 *db, /* Database handle to read schema from */ |
| const char *zDb /* Name of db - "main", "temp" etc. */ |
| ){ |
| int rc = SQLITE_OK; |
| |
| if( pTab->nCol==0 ){ |
| u8 *abPK; |
| assert( pTab->azCol==0 || pTab->abPK==0 ); |
| rc = sessionTableInfo(pSession, db, zDb, |
| pTab->zName, &pTab->nCol, 0, &pTab->azCol, &pTab->azDflt, &abPK, |
| ((pSession==0 || pSession->bImplicitPK) ? &pTab->bRowid : 0) |
| ); |
| if( rc==SQLITE_OK ){ |
| int i; |
| for(i=0; i<pTab->nCol; i++){ |
| if( abPK[i] ){ |
| pTab->abPK = abPK; |
| break; |
| } |
| } |
| if( 0==sqlite3_stricmp("sqlite_stat1", pTab->zName) ){ |
| pTab->bStat1 = 1; |
| } |
| |
| if( pSession && pSession->bEnableSize ){ |
| pSession->nMaxChangesetSize += ( |
| 1 + sessionVarintLen(pTab->nCol) + pTab->nCol + strlen(pTab->zName)+1 |
| ); |
| } |
| } |
| } |
| |
| if( pSession ){ |
| pSession->rc = rc; |
| return (rc || pTab->abPK==0); |
| } |
| return rc; |
| } |
| |
| /* |
| ** Re-initialize table object pTab. |
| */ |
| static int sessionReinitTable(sqlite3_session *pSession, SessionTable *pTab){ |
| int nCol = 0; |
| const char **azCol = 0; |
| const char **azDflt = 0; |
| u8 *abPK = 0; |
| int bRowid = 0; |
| |
| assert( pSession->rc==SQLITE_OK ); |
| |
| pSession->rc = sessionTableInfo(pSession, pSession->db, pSession->zDb, |
| pTab->zName, &nCol, 0, &azCol, &azDflt, &abPK, |
| (pSession->bImplicitPK ? &bRowid : 0) |
| ); |
| if( pSession->rc==SQLITE_OK ){ |
| if( pTab->nCol>nCol || pTab->bRowid!=bRowid ){ |
| pSession->rc = SQLITE_SCHEMA; |
| }else{ |
| int ii; |
| int nOldCol = pTab->nCol; |
| for(ii=0; ii<nCol; ii++){ |
| if( ii<pTab->nCol ){ |
| if( pTab->abPK[ii]!=abPK[ii] ){ |
| pSession->rc = SQLITE_SCHEMA; |
| } |
| }else if( abPK[ii] ){ |
| pSession->rc = SQLITE_SCHEMA; |
| } |
| } |
| |
| if( pSession->rc==SQLITE_OK ){ |
| const char **a = pTab->azCol; |
| pTab->azCol = azCol; |
| pTab->nCol = nCol; |
| pTab->azDflt = azDflt; |
| pTab->abPK = abPK; |
| azCol = a; |
| } |
| if( pSession->bEnableSize ){ |
| pSession->nMaxChangesetSize += (nCol - nOldCol); |
| pSession->nMaxChangesetSize += sessionVarintLen(nCol); |
| pSession->nMaxChangesetSize -= sessionVarintLen(nOldCol); |
| } |
| } |
| } |
| |
| sqlite3_free((char*)azCol); |
| return pSession->rc; |
| } |
| |
| /* |
| ** Session-change object (*pp) contains an old.* record with fewer than |
| ** nCol fields. This function updates it with the default values for |
| ** the missing fields. |
| */ |
| static void sessionUpdateOneChange( |
| sqlite3_session *pSession, /* For memory accounting */ |
| int *pRc, /* IN/OUT: Error code */ |
| SessionChange **pp, /* IN/OUT: Change object to update */ |
| int nCol, /* Number of columns now in table */ |
| sqlite3_stmt *pDflt /* SELECT <default-values...> */ |
| ){ |
| SessionChange *pOld = *pp; |
| |
| while( pOld->nRecordField<nCol ){ |
| SessionChange *pNew = 0; |
| int nByte = 0; |
| int nIncr = 0; |
| int iField = pOld->nRecordField; |
| int eType = sqlite3_column_type(pDflt, iField); |
| switch( eType ){ |
| case SQLITE_NULL: |
| nIncr = 1; |
| break; |
| case SQLITE_INTEGER: |
| case SQLITE_FLOAT: |
| nIncr = 9; |
| break; |
| default: { |
| int n = sqlite3_column_bytes(pDflt, iField); |
| nIncr = 1 + sessionVarintLen(n) + n; |
| assert( eType==SQLITE_TEXT || eType==SQLITE_BLOB ); |
| break; |
| } |
| } |
| |
| nByte = nIncr + (sizeof(SessionChange) + pOld->nRecord); |
| pNew = sessionMalloc64(pSession, nByte); |
| if( pNew==0 ){ |
| *pRc = SQLITE_NOMEM; |
| return; |
| }else{ |
| memcpy(pNew, pOld, sizeof(SessionChange)); |
| pNew->aRecord = (u8*)&pNew[1]; |
| memcpy(pNew->aRecord, pOld->aRecord, pOld->nRecord); |
| pNew->aRecord[pNew->nRecord++] = (u8)eType; |
| switch( eType ){ |
| case SQLITE_INTEGER: { |
| i64 iVal = sqlite3_column_int64(pDflt, iField); |
| sessionPutI64(&pNew->aRecord[pNew->nRecord], iVal); |
| pNew->nRecord += 8; |
| break; |
| } |
| |
| case SQLITE_FLOAT: { |
| double rVal = sqlite3_column_double(pDflt, iField); |
| i64 iVal = 0; |
| memcpy(&iVal, &rVal, sizeof(rVal)); |
| sessionPutI64(&pNew->aRecord[pNew->nRecord], iVal); |
| pNew->nRecord += 8; |
| break; |
| } |
| |
| case SQLITE_TEXT: { |
| int n = sqlite3_column_bytes(pDflt, iField); |
| const char *z = (const char*)sqlite3_column_text(pDflt, iField); |
| pNew->nRecord += sessionVarintPut(&pNew->aRecord[pNew->nRecord], n); |
| memcpy(&pNew->aRecord[pNew->nRecord], z, n); |
| pNew->nRecord += n; |
| break; |
| } |
| |
| case SQLITE_BLOB: { |
| int n = sqlite3_column_bytes(pDflt, iField); |
| const u8 *z = (const u8*)sqlite3_column_blob(pDflt, iField); |
| pNew->nRecord += sessionVarintPut(&pNew->aRecord[pNew->nRecord], n); |
| memcpy(&pNew->aRecord[pNew->nRecord], z, n); |
| pNew->nRecord += n; |
| break; |
| } |
| |
| default: |
| assert( eType==SQLITE_NULL ); |
| break; |
| } |
| |
| sessionFree(pSession, pOld); |
| *pp = pOld = pNew; |
| pNew->nRecordField++; |
| pNew->nMaxSize += nIncr; |
| if( pSession ){ |
| pSession->nMaxChangesetSize += nIncr; |
| } |
| } |
| } |
| } |
| |
| /* |
| ** Ensure that there is room in the buffer to append nByte bytes of data. |
| ** If not, use sqlite3_realloc() to grow the buffer so that there is. |
| ** |
| ** If successful, return zero. Otherwise, if an OOM condition is encountered, |
| ** set *pRc to SQLITE_NOMEM and return non-zero. |
| */ |
| static int sessionBufferGrow(SessionBuffer *p, i64 nByte, int *pRc){ |
| #define SESSION_MAX_BUFFER_SZ (0x7FFFFF00 - 1) |
| i64 nReq = p->nBuf + nByte; |
| if( *pRc==SQLITE_OK && nReq>p->nAlloc ){ |
| u8 *aNew; |
| i64 nNew = p->nAlloc ? p->nAlloc : 128; |
| |
| do { |
| nNew = nNew*2; |
| }while( nNew<nReq ); |
| |
| /* The value of SESSION_MAX_BUFFER_SZ is copied from the implementation |
| ** of sqlite3_realloc64(). Allocations greater than this size in bytes |
| ** always fail. It is used here to ensure that this routine can always |
| ** allocate up to this limit - instead of up to the largest power of |
| ** two smaller than the limit. */ |
| if( nNew>SESSION_MAX_BUFFER_SZ ){ |
| nNew = SESSION_MAX_BUFFER_SZ; |
| if( nNew<nReq ){ |
| *pRc = SQLITE_NOMEM; |
| return 1; |
| } |
| } |
| |
| aNew = (u8 *)sqlite3_realloc64(p->aBuf, nNew); |
| if( 0==aNew ){ |
| *pRc = SQLITE_NOMEM; |
| }else{ |
| p->aBuf = aNew; |
| p->nAlloc = nNew; |
| } |
| } |
| return (*pRc!=SQLITE_OK); |
| } |
| |
| |
| /* |
| ** This function is a no-op if *pRc is other than SQLITE_OK when it is |
| ** called. Otherwise, append a string to the buffer. All bytes in the string |
| ** up to (but not including) the nul-terminator are written to the buffer. |
| ** |
| ** If an OOM condition is encountered, set *pRc to SQLITE_NOMEM before |
| ** returning. |
| */ |
| static void sessionAppendStr( |
| SessionBuffer *p, |
| const char *zStr, |
| int *pRc |
| ){ |
| int nStr = sqlite3Strlen30(zStr); |
| if( 0==sessionBufferGrow(p, nStr+1, pRc) ){ |
| memcpy(&p->aBuf[p->nBuf], zStr, nStr); |
| p->nBuf += nStr; |
| p->aBuf[p->nBuf] = 0x00; |
| } |
| } |
| |
| /* |
| ** Format a string using printf() style formatting and then append it to the |
| ** buffer using sessionAppendString(). |
| */ |
| static void sessionAppendPrintf( |
| SessionBuffer *p, /* Buffer to append to */ |
| int *pRc, |
| const char *zFmt, |
| ... |
| ){ |
| if( *pRc==SQLITE_OK ){ |
| char *zApp = 0; |
| va_list ap; |
| va_start(ap, zFmt); |
| zApp = sqlite3_vmprintf(zFmt, ap); |
| if( zApp==0 ){ |
| *pRc = SQLITE_NOMEM; |
| }else{ |
| sessionAppendStr(p, zApp, pRc); |
| } |
| va_end(ap); |
| sqlite3_free(zApp); |
| } |
| } |
| |
| /* |
| ** Prepare a statement against database handle db that SELECTs a single |
| ** row containing the default values for each column in table pTab. For |
| ** example, if pTab is declared as: |
| ** |
| ** CREATE TABLE pTab(a PRIMARY KEY, b DEFAULT 123, c DEFAULT 'abcd'); |
| ** |
| ** Then this function prepares and returns the SQL statement: |
| ** |
| ** SELECT NULL, 123, 'abcd'; |
| */ |
| static int sessionPrepareDfltStmt( |
| sqlite3 *db, /* Database handle */ |
| SessionTable *pTab, /* Table to prepare statement for */ |
| sqlite3_stmt **ppStmt /* OUT: Statement handle */ |
| ){ |
| SessionBuffer sql = {0,0,0}; |
| int rc = SQLITE_OK; |
| const char *zSep = " "; |
| int ii = 0; |
| |
| *ppStmt = 0; |
| sessionAppendPrintf(&sql, &rc, "SELECT"); |
| for(ii=0; ii<pTab->nCol; ii++){ |
| const char *zDflt = pTab->azDflt[ii] ? pTab->azDflt[ii] : "NULL"; |
| sessionAppendPrintf(&sql, &rc, "%s%s", zSep, zDflt); |
| zSep = ", "; |
| } |
| if( rc==SQLITE_OK ){ |
| rc = sqlite3_prepare_v2(db, (const char*)sql.aBuf, -1, ppStmt, 0); |
| } |
| sqlite3_free(sql.aBuf); |
| |
| return rc; |
| } |
| |
| /* |
| ** Table pTab has one or more existing change-records with old.* records |
| ** with fewer than pTab->nCol columns. This function updates all such |
| ** change-records with the default values for the missing columns. |
| */ |
| static int sessionUpdateChanges(sqlite3_session *pSession, SessionTable *pTab){ |
| sqlite3_stmt *pStmt = 0; |
| int rc = pSession->rc; |
| |
| rc = sessionPrepareDfltStmt(pSession->db, pTab, &pStmt); |
| if( rc==SQLITE_OK && SQLITE_ROW==sqlite3_step(pStmt) ){ |
| int ii = 0; |
| SessionChange **pp = 0; |
| for(ii=0; ii<pTab->nChange; ii++){ |
| for(pp=&pTab->apChange[ii]; *pp; pp=&((*pp)->pNext)){ |
| if( (*pp)->nRecordField!=pTab->nCol ){ |
| sessionUpdateOneChange(pSession, &rc, pp, pTab->nCol, pStmt); |
| } |
| } |
| } |
| } |
| |
| pSession->rc = rc; |
| rc = sqlite3_finalize(pStmt); |
| if( pSession->rc==SQLITE_OK ) pSession->rc = rc; |
| return pSession->rc; |
| } |
| |
| /* |
| ** Versions of the four methods in object SessionHook for use with the |
| ** sqlite_stat1 table. The purpose of this is to substitute a zero-length |
| ** blob each time a NULL value is read from the "idx" column of the |
| ** sqlite_stat1 table. |
| */ |
| typedef struct SessionStat1Ctx SessionStat1Ctx; |
| struct SessionStat1Ctx { |
| SessionHook hook; |
| sqlite3_session *pSession; |
| }; |
| static int sessionStat1Old(void *pCtx, int iCol, sqlite3_value **ppVal){ |
| SessionStat1Ctx *p = (SessionStat1Ctx*)pCtx; |
| sqlite3_value *pVal = 0; |
| int rc = p->hook.xOld(p->hook.pCtx, iCol, &pVal); |
| if( rc==SQLITE_OK && iCol==1 && sqlite3_value_type(pVal)==SQLITE_NULL ){ |
| pVal = p->pSession->pZeroBlob; |
| } |
| *ppVal = pVal; |
| return rc; |
| } |
| static int sessionStat1New(void *pCtx, int iCol, sqlite3_value **ppVal){ |
| SessionStat1Ctx *p = (SessionStat1Ctx*)pCtx; |
| sqlite3_value *pVal = 0; |
| int rc = p->hook.xNew(p->hook.pCtx, iCol, &pVal); |
| if( rc==SQLITE_OK && iCol==1 && sqlite3_value_type(pVal)==SQLITE_NULL ){ |
| pVal = p->pSession->pZeroBlob; |
| } |
| *ppVal = pVal; |
| return rc; |
| } |
| static int sessionStat1Count(void *pCtx){ |
| SessionStat1Ctx *p = (SessionStat1Ctx*)pCtx; |
| return p->hook.xCount(p->hook.pCtx); |
| } |
| static int sessionStat1Depth(void *pCtx){ |
| SessionStat1Ctx *p = (SessionStat1Ctx*)pCtx; |
| return p->hook.xDepth(p->hook.pCtx); |
| } |
| |
| static int sessionUpdateMaxSize( |
| int op, |
| sqlite3_session *pSession, /* Session object pTab is attached to */ |
| SessionTable *pTab, /* Table that change applies to */ |
| SessionChange *pC /* Update pC->nMaxSize */ |
| ){ |
| i64 nNew = 2; |
| if( pC->op==SQLITE_INSERT ){ |
| if( pTab->bRowid ) nNew += 9; |
| if( op!=SQLITE_DELETE ){ |
| int ii; |
| for(ii=0; ii<pTab->nCol; ii++){ |
| sqlite3_value *p = 0; |
| pSession->hook.xNew(pSession->hook.pCtx, ii, &p); |
| sessionSerializeValue(0, p, &nNew); |
| } |
| } |
| }else if( op==SQLITE_DELETE ){ |
| nNew += pC->nRecord; |
| if( sqlite3_preupdate_blobwrite(pSession->db)>=0 ){ |
| nNew += pC->nRecord; |
| } |
| }else{ |
| int ii; |
| u8 *pCsr = pC->aRecord; |
| if( pTab->bRowid ){ |
| nNew += 9 + 1; |
| pCsr += 9; |
| } |
| for(ii=pTab->bRowid; ii<pTab->nCol; ii++){ |
| int bChanged = 1; |
| int nOld = 0; |
| int eType; |
| sqlite3_value *p = 0; |
| pSession->hook.xNew(pSession->hook.pCtx, ii-pTab->bRowid, &p); |
| if( p==0 ){ |
| return SQLITE_NOMEM; |
| } |
| |
| eType = *pCsr++; |
| switch( eType ){ |
| case SQLITE_NULL: |
| bChanged = sqlite3_value_type(p)!=SQLITE_NULL; |
| break; |
| |
| case SQLITE_FLOAT: |
| case SQLITE_INTEGER: { |
| if( eType==sqlite3_value_type(p) ){ |
| sqlite3_int64 iVal = sessionGetI64(pCsr); |
| if( eType==SQLITE_INTEGER ){ |
| bChanged = (iVal!=sqlite3_value_int64(p)); |
| }else{ |
| double dVal; |
| memcpy(&dVal, &iVal, 8); |
| bChanged = (dVal!=sqlite3_value_double(p)); |
| } |
| } |
| nOld = 8; |
| pCsr += 8; |
| break; |
| } |
| |
| default: { |
| int nByte; |
| nOld = sessionVarintGet(pCsr, &nByte); |
| pCsr += nOld; |
| nOld += nByte; |
| assert( eType==SQLITE_TEXT || eType==SQLITE_BLOB ); |
| if( eType==sqlite3_value_type(p) |
| && nByte==sqlite3_value_bytes(p) |
| && (nByte==0 || 0==memcmp(pCsr, sqlite3_value_blob(p), nByte)) |
| ){ |
| bChanged = 0; |
| } |
| pCsr += nByte; |
| break; |
| } |
| } |
| |
| if( bChanged && pTab->abPK[ii] ){ |
| nNew = pC->nRecord + 2; |
| break; |
| } |
| |
| if( bChanged ){ |
| nNew += 1 + nOld; |
| sessionSerializeValue(0, p, &nNew); |
| }else if( pTab->abPK[ii] ){ |
| nNew += 2 + nOld; |
| }else{ |
| nNew += 2; |
| } |
| } |
| } |
| |
| if( nNew>pC->nMaxSize ){ |
| int nIncr = nNew - pC->nMaxSize; |
| pC->nMaxSize = nNew; |
| pSession->nMaxChangesetSize += nIncr; |
| } |
| return SQLITE_OK; |
| } |
| |
| /* |
| ** This function is only called from with a pre-update-hook reporting a |
| ** change on table pTab (attached to session pSession). The type of change |
| ** (UPDATE, INSERT, DELETE) is specified by the first argument. |
| ** |
| ** Unless one is already present or an error occurs, an entry is added |
| ** to the changed-rows hash table associated with table pTab. |
| */ |
| static void sessionPreupdateOneChange( |
| int op, /* One of SQLITE_UPDATE, INSERT, DELETE */ |
| i64 iRowid, |
| sqlite3_session *pSession, /* Session object pTab is attached to */ |
| SessionTable *pTab /* Table that change applies to */ |
| ){ |
| int iHash; |
| int bNull = 0; |
| int rc = SQLITE_OK; |
| int nExpect = 0; |
| SessionStat1Ctx stat1 = {{0,0,0,0,0},0}; |
| |
| if( pSession->rc ) return; |
| |
| /* Load table details if required */ |
| if( sessionInitTable(pSession, pTab, pSession->db, pSession->zDb) ) return; |
| |
| /* Check the number of columns in this xPreUpdate call matches the |
| ** number of columns in the table. */ |
| nExpect = pSession->hook.xCount(pSession->hook.pCtx); |
| if( (pTab->nCol-pTab->bRowid)<nExpect ){ |
| if( sessionReinitTable(pSession, pTab) ) return; |
| if( sessionUpdateChanges(pSession, pTab) ) return; |
| } |
| if( (pTab->nCol-pTab->bRowid)!=nExpect ){ |
| pSession->rc = SQLITE_SCHEMA; |
| return; |
| } |
| |
| /* Grow the hash table if required */ |
| if( sessionGrowHash(pSession, 0, pTab) ){ |
| pSession->rc = SQLITE_NOMEM; |
| return; |
| } |
| |
| if( pTab->bStat1 ){ |
| stat1.hook = pSession->hook; |
| stat1.pSession = pSession; |
| pSession->hook.pCtx = (void*)&stat1; |
| pSession->hook.xNew = sessionStat1New; |
| pSession->hook.xOld = sessionStat1Old; |
| pSession->hook.xCount = sessionStat1Count; |
| pSession->hook.xDepth = sessionStat1Depth; |
| if( pSession->pZeroBlob==0 ){ |
| sqlite3_value *p = sqlite3ValueNew(0); |
| if( p==0 ){ |
| rc = SQLITE_NOMEM; |
| goto error_out; |
| } |
| sqlite3ValueSetStr(p, 0, "", 0, SQLITE_STATIC); |
| pSession->pZeroBlob = p; |
| } |
| } |
| |
| /* Calculate the hash-key for this change. If the primary key of the row |
| ** includes a NULL value, exit early. Such changes are ignored by the |
| ** session module. */ |
| rc = sessionPreupdateHash( |
| pSession, iRowid, pTab, op==SQLITE_INSERT, &iHash, &bNull |
| ); |
| if( rc!=SQLITE_OK ) goto error_out; |
| |
| if( bNull==0 ){ |
| /* Search the hash table for an existing record for this row. */ |
| SessionChange *pC; |
| for(pC=pTab->apChange[iHash]; pC; pC=pC->pNext){ |
| if( sessionPreupdateEqual(pSession, iRowid, pTab, pC, op) ) break; |
| } |
| |
| if( pC==0 ){ |
| /* Create a new change object containing all the old values (if |
| ** this is an SQLITE_UPDATE or SQLITE_DELETE), or just the PK |
| ** values (if this is an INSERT). */ |
| sqlite3_int64 nByte; /* Number of bytes to allocate */ |
| int i; /* Used to iterate through columns */ |
| |
| assert( rc==SQLITE_OK ); |
| pTab->nEntry++; |
| |
| /* Figure out how large an allocation is required */ |
| nByte = sizeof(SessionChange); |
| for(i=0; i<(pTab->nCol-pTab->bRowid); i++){ |
| sqlite3_value *p = 0; |
| if( op!=SQLITE_INSERT ){ |
| TESTONLY(int trc = ) pSession->hook.xOld(pSession->hook.pCtx, i, &p); |
| assert( trc==SQLITE_OK ); |
| }else if( pTab->abPK[i] ){ |
| TESTONLY(int trc = ) pSession->hook.xNew(pSession->hook.pCtx, i, &p); |
| assert( trc==SQLITE_OK ); |
| } |
| |
| /* This may fail if SQLite value p contains a utf-16 string that must |
| ** be converted to utf-8 and an OOM error occurs while doing so. */ |
| rc = sessionSerializeValue(0, p, &nByte); |
| if( rc!=SQLITE_OK ) goto error_out; |
| } |
| if( pTab->bRowid ){ |
| nByte += 9; /* Size of rowid field - an integer */ |
| } |
| |
| /* Allocate the change object */ |
| pC = (SessionChange*)sessionMalloc64(pSession, nByte); |
| if( !pC ){ |
| rc = SQLITE_NOMEM; |
| goto error_out; |
| }else{ |
| memset(pC, 0, sizeof(SessionChange)); |
| pC->aRecord = (u8 *)&pC[1]; |
| } |
| |
| /* Populate the change object. None of the preupdate_old(), |
| ** preupdate_new() or SerializeValue() calls below may fail as all |
| ** required values and encodings have already been cached in memory. |
| ** It is not possible for an OOM to occur in this block. */ |
| nByte = 0; |
| if( pTab->bRowid ){ |
| pC->aRecord[0] = SQLITE_INTEGER; |
| sessionPutI64(&pC->aRecord[1], iRowid); |
| nByte = 9; |
| } |
| for(i=0; i<(pTab->nCol-pTab->bRowid); i++){ |
| sqlite3_value *p = 0; |
| if( op!=SQLITE_INSERT ){ |
| pSession->hook.xOld(pSession->hook.pCtx, i, &p); |
| }else if( pTab->abPK[i] ){ |
| pSession->hook.xNew(pSession->hook.pCtx, i, &p); |
| } |
| sessionSerializeValue(&pC->aRecord[nByte], p, &nByte); |
| } |
| |
| /* Add the change to the hash-table */ |
| if( pSession->bIndirect || pSession->hook.xDepth(pSession->hook.pCtx) ){ |
| pC->bIndirect = 1; |
| } |
| pC->nRecordField = pTab->nCol; |
| pC->nRecord = nByte; |
| pC->op = op; |
| pC->pNext = pTab->apChange[iHash]; |
| pTab->apChange[iHash] = pC; |
| |
| }else if( pC->bIndirect ){ |
| /* If the existing change is considered "indirect", but this current |
| ** change is "direct", mark the change object as direct. */ |
| if( pSession->hook.xDepth(pSession->hook.pCtx)==0 |
| && pSession->bIndirect==0 |
| ){ |
| pC->bIndirect = 0; |
| } |
| } |
| |
| assert( rc==SQLITE_OK ); |
| if( pSession->bEnableSize ){ |
| rc = sessionUpdateMaxSize(op, pSession, pTab, pC); |
| } |
| } |
| |
| |
| /* If an error has occurred, mark the session object as failed. */ |
| error_out: |
| if( pTab->bStat1 ){ |
| pSession->hook = stat1.hook; |
| } |
| if( rc!=SQLITE_OK ){ |
| pSession->rc = rc; |
| } |
| } |
| |
| static int sessionFindTable( |
| sqlite3_session *pSession, |
| const char *zName, |
| SessionTable **ppTab |
| ){ |
| int rc = SQLITE_OK; |
| int nName = sqlite3Strlen30(zName); |
| SessionTable *pRet; |
| |
| /* Search for an existing table */ |
| for(pRet=pSession->pTable; pRet; pRet=pRet->pNext){ |
| if( 0==sqlite3_strnicmp(pRet->zName, zName, nName+1) ) break; |
| } |
| |
| if( pRet==0 && pSession->bAutoAttach ){ |
| /* If there is a table-filter configured, invoke it. If it returns 0, |
| ** do not automatically add the new table. */ |
| if( pSession->xTableFilter==0 |
| || pSession->xTableFilter(pSession->pFilterCtx, zName) |
| ){ |
| rc = sqlite3session_attach(pSession, zName); |
| if( rc==SQLITE_OK ){ |
| pRet = pSession->pTable; |
| while( ALWAYS(pRet) && pRet->pNext ){ |
| pRet = pRet->pNext; |
| } |
| assert( pRet!=0 ); |
| assert( 0==sqlite3_strnicmp(pRet->zName, zName, nName+1) ); |
| } |
| } |
| } |
| |
| assert( rc==SQLITE_OK || pRet==0 ); |
| *ppTab = pRet; |
| return rc; |
| } |
| |
| /* |
| ** The 'pre-update' hook registered by this module with SQLite databases. |
| */ |
| static void xPreUpdate( |
| void *pCtx, /* Copy of third arg to preupdate_hook() */ |
| sqlite3 *db, /* Database handle */ |
| int op, /* SQLITE_UPDATE, DELETE or INSERT */ |
| char const *zDb, /* Database name */ |
| char const *zName, /* Table name */ |
| sqlite3_int64 iKey1, /* Rowid of row about to be deleted/updated */ |
| sqlite3_int64 iKey2 /* New rowid value (for a rowid UPDATE) */ |
| ){ |
| sqlite3_session *pSession; |
| int nDb = sqlite3Strlen30(zDb); |
| |
| assert( sqlite3_mutex_held(db->mutex) ); |
| (void)iKey1; |
| (void)iKey2; |
| |
| for(pSession=(sqlite3_session *)pCtx; pSession; pSession=pSession->pNext){ |
| SessionTable *pTab; |
| |
| /* If this session is attached to a different database ("main", "temp" |
| ** etc.), or if it is not currently enabled, there is nothing to do. Skip |
| ** to the next session object attached to this database. */ |
| if( pSession->bEnable==0 ) continue; |
| if( pSession->rc ) continue; |
| if( sqlite3_strnicmp(zDb, pSession->zDb, nDb+1) ) continue; |
| |
| pSession->rc = sessionFindTable(pSession, zName, &pTab); |
| if( pTab ){ |
| assert( pSession->rc==SQLITE_OK ); |
| assert( op==SQLITE_UPDATE || iKey1==iKey2 ); |
| sessionPreupdateOneChange(op, iKey1, pSession, pTab); |
| if( op==SQLITE_UPDATE ){ |
| sessionPreupdateOneChange(SQLITE_INSERT, iKey2, pSession, pTab); |
| } |
| } |
| } |
| } |
| |
| /* |
| ** The pre-update hook implementations. |
| */ |
| static int sessionPreupdateOld(void *pCtx, int iVal, sqlite3_value **ppVal){ |
| return sqlite3_preupdate_old((sqlite3*)pCtx, iVal, ppVal); |
| } |
| static int sessionPreupdateNew(void *pCtx, int iVal, sqlite3_value **ppVal){ |
| return sqlite3_preupdate_new((sqlite3*)pCtx, iVal, ppVal); |
| } |
| static int sessionPreupdateCount(void *pCtx){ |
| return sqlite3_preupdate_count((sqlite3*)pCtx); |
| } |
| static int sessionPreupdateDepth(void *pCtx){ |
| return sqlite3_preupdate_depth((sqlite3*)pCtx); |
| } |
| |
| /* |
| ** Install the pre-update hooks on the session object passed as the only |
| ** argument. |
| */ |
| static void sessionPreupdateHooks( |
| sqlite3_session *pSession |
| ){ |
| pSession->hook.pCtx = (void*)pSession->db; |
| pSession->hook.xOld = sessionPreupdateOld; |
| pSession->hook.xNew = sessionPreupdateNew; |
| pSession->hook.xCount = sessionPreupdateCount; |
| pSession->hook.xDepth = sessionPreupdateDepth; |
| } |
| |
| typedef struct SessionDiffCtx SessionDiffCtx; |
| struct SessionDiffCtx { |
| sqlite3_stmt *pStmt; |
| int bRowid; |
| int nOldOff; |
| }; |
| |
| /* |
| ** The diff hook implementations. |
| */ |
| static int sessionDiffOld(void *pCtx, int iVal, sqlite3_value **ppVal){ |
| SessionDiffCtx *p = (SessionDiffCtx*)pCtx; |
| *ppVal = sqlite3_column_value(p->pStmt, iVal+p->nOldOff+p->bRowid); |
| return SQLITE_OK; |
| } |
| static int sessionDiffNew(void *pCtx, int iVal, sqlite3_value **ppVal){ |
| SessionDiffCtx *p = (SessionDiffCtx*)pCtx; |
| *ppVal = sqlite3_column_value(p->pStmt, iVal+p->bRowid); |
| return SQLITE_OK; |
| } |
| static int sessionDiffCount(void *pCtx){ |
| SessionDiffCtx *p = (SessionDiffCtx*)pCtx; |
| return (p->nOldOff ? p->nOldOff : sqlite3_column_count(p->pStmt)) - p->bRowid; |
| } |
| static int sessionDiffDepth(void *pCtx){ |
| (void)pCtx; |
| return 0; |
| } |
| |
| /* |
| ** Install the diff hooks on the session object passed as the only |
| ** argument. |
| */ |
| static void sessionDiffHooks( |
| sqlite3_session *pSession, |
| SessionDiffCtx *pDiffCtx |
| ){ |
| pSession->hook.pCtx = (void*)pDiffCtx; |
| pSession->hook.xOld = sessionDiffOld; |
| pSession->hook.xNew = sessionDiffNew; |
| pSession->hook.xCount = sessionDiffCount; |
| pSession->hook.xDepth = sessionDiffDepth; |
| } |
| |
| static char *sessionExprComparePK( |
| int nCol, |
| const char *zDb1, const char *zDb2, |
| const char *zTab, |
| const char **azCol, u8 *abPK |
| ){ |
| int i; |
| const char *zSep = ""; |
| char *zRet = 0; |
| |
| for(i=0; i<nCol; i++){ |
| if( abPK[i] ){ |
| zRet = sqlite3_mprintf("%z%s\"%w\".\"%w\".\"%w\"=\"%w\".\"%w\".\"%w\"", |
| zRet, zSep, zDb1, zTab, azCol[i], zDb2, zTab, azCol[i] |
| ); |
| zSep = " AND "; |
| if( zRet==0 ) break; |
| } |
| } |
| |
| return zRet; |
| } |
| |
| static char *sessionExprCompareOther( |
| int nCol, |
| const char *zDb1, const char *zDb2, |
| const char *zTab, |
| const char **azCol, u8 *abPK |
| ){ |
| int i; |
| const char *zSep = ""; |
| char *zRet = 0; |
| int bHave = 0; |
| |
| for(i=0; i<nCol; i++){ |
| if( abPK[i]==0 ){ |
| bHave = 1; |
| zRet = sqlite3_mprintf( |
| "%z%s\"%w\".\"%w\".\"%w\" IS NOT \"%w\".\"%w\".\"%w\"", |
| zRet, zSep, zDb1, zTab, azCol[i], zDb2, zTab, azCol[i] |
| ); |
| zSep = " OR "; |
| if( zRet==0 ) break; |
| } |
| } |
| |
| if( bHave==0 ){ |
| assert( zRet==0 ); |
| zRet = sqlite3_mprintf("0"); |
| } |
| |
| return zRet; |
| } |
| |
| static char *sessionSelectFindNew( |
| const char *zDb1, /* Pick rows in this db only */ |
| const char *zDb2, /* But not in this one */ |
| int bRowid, |
| const char *zTbl, /* Table name */ |
| const char *zExpr |
| ){ |
| const char *zSel = (bRowid ? SESSIONS_ROWID ", *" : "*"); |
| char *zRet = sqlite3_mprintf( |
| "SELECT %s FROM \"%w\".\"%w\" WHERE NOT EXISTS (" |
| " SELECT 1 FROM \"%w\".\"%w\" WHERE %s" |
| ")", |
| zSel, zDb1, zTbl, zDb2, zTbl, zExpr |
| ); |
| return zRet; |
| } |
| |
| static int sessionDiffFindNew( |
| int op, |
| sqlite3_session *pSession, |
| SessionTable *pTab, |
| const char *zDb1, |
| const char *zDb2, |
| char *zExpr |
| ){ |
| int rc = SQLITE_OK; |
| char *zStmt = sessionSelectFindNew( |
| zDb1, zDb2, pTab->bRowid, pTab->zName, zExpr |
| ); |
| |
| if( zStmt==0 ){ |
| rc = SQLITE_NOMEM; |
| }else{ |
| sqlite3_stmt *pStmt; |
| rc = sqlite3_prepare(pSession->db, zStmt, -1, &pStmt, 0); |
| if( rc==SQLITE_OK ){ |
| SessionDiffCtx *pDiffCtx = (SessionDiffCtx*)pSession->hook.pCtx; |
| pDiffCtx->pStmt = pStmt; |
| pDiffCtx->nOldOff = 0; |
| pDiffCtx->bRowid = pTab->bRowid; |
| while( SQLITE_ROW==sqlite3_step(pStmt) ){ |
| i64 iRowid = (pTab->bRowid ? sqlite3_column_int64(pStmt, 0) : 0); |
| sessionPreupdateOneChange(op, iRowid, pSession, pTab); |
| } |
| rc = sqlite3_finalize(pStmt); |
| } |
| sqlite3_free(zStmt); |
| } |
| |
| return rc; |
| } |
| |
| /* |
| ** Return a comma-separated list of the fully-qualified (with both database |
| ** and table name) column names from table pTab. e.g. |
| ** |
| ** "main"."t1"."a", "main"."t1"."b", "main"."t1"."c" |
| */ |
| static char *sessionAllCols( |
| const char *zDb, |
| SessionTable *pTab |
| ){ |
| int ii; |
| char *zRet = 0; |
| for(ii=0; ii<pTab->nCol; ii++){ |
| zRet = sqlite3_mprintf("%z%s\"%w\".\"%w\".\"%w\"", |
| zRet, (zRet ? ", " : ""), zDb, pTab->zName, pTab->azCol[ii] |
| ); |
| if( !zRet ) break; |
| } |
| return zRet; |
| } |
| |
| static int sessionDiffFindModified( |
| sqlite3_session *pSession, |
| SessionTable *pTab, |
| const char *zFrom, |
| const char *zExpr |
| ){ |
| int rc = SQLITE_OK; |
| |
| char *zExpr2 = sessionExprCompareOther(pTab->nCol, |
| pSession->zDb, zFrom, pTab->zName, pTab->azCol, pTab->abPK |
| ); |
| if( zExpr2==0 ){ |
| rc = SQLITE_NOMEM; |
| }else{ |
| char *z1 = sessionAllCols(pSession->zDb, pTab); |
| char *z2 = sessionAllCols(zFrom, pTab); |
| char *zStmt = sqlite3_mprintf( |
| "SELECT %s,%s FROM \"%w\".\"%w\", \"%w\".\"%w\" WHERE %s AND (%z)", |
| z1, z2, pSession->zDb, pTab->zName, zFrom, pTab->zName, zExpr, zExpr2 |
| ); |
| if( zStmt==0 || z1==0 || z2==0 ){ |
| rc = SQLITE_NOMEM; |
| }else{ |
| sqlite3_stmt *pStmt; |
| rc = sqlite3_prepare(pSession->db, zStmt, -1, &pStmt, 0); |
| |
| if( rc==SQLITE_OK ){ |
| SessionDiffCtx *pDiffCtx = (SessionDiffCtx*)pSession->hook.pCtx; |
| pDiffCtx->pStmt = pStmt; |
| pDiffCtx->nOldOff = pTab->nCol; |
| while( SQLITE_ROW==sqlite3_step(pStmt) ){ |
| i64 iRowid = (pTab->bRowid ? sqlite3_column_int64(pStmt, 0) : 0); |
| sessionPreupdateOneChange(SQLITE_UPDATE, iRowid, pSession, pTab); |
| } |
| rc = sqlite3_finalize(pStmt); |
| } |
| } |
| sqlite3_free(zStmt); |
| sqlite3_free(z1); |
| sqlite3_free(z2); |
| } |
| |
| return rc; |
| } |
| |
| int sqlite3session_diff( |
| sqlite3_session *pSession, |
| const char *zFrom, |
| const char *zTbl, |
| char **pzErrMsg |
| ){ |
| const char *zDb = pSession->zDb; |
| int rc = pSession->rc; |
| SessionDiffCtx d; |
| |
| memset(&d, 0, sizeof(d)); |
| sessionDiffHooks(pSession, &d); |
| |
| sqlite3_mutex_enter(sqlite3_db_mutex(pSession->db)); |
| if( pzErrMsg ) *pzErrMsg = 0; |
| if( rc==SQLITE_OK ){ |
| char *zExpr = 0; |
| sqlite3 *db = pSession->db; |
| SessionTable *pTo; /* Table zTbl */ |
| |
| /* Locate and if necessary initialize the target table object */ |
| rc = sessionFindTable(pSession, zTbl, &pTo); |
| if( pTo==0 ) goto diff_out; |
| if( sessionInitTable(pSession, pTo, pSession->db, pSession->zDb) ){ |
| rc = pSession->rc; |
| goto diff_out; |
| } |
| |
| /* Check the table schemas match */ |
| if( rc==SQLITE_OK ){ |
| int bHasPk = 0; |
| int bMismatch = 0; |
| int nCol; /* Columns in zFrom.zTbl */ |
| int bRowid = 0; |
| u8 *abPK; |
| const char **azCol = 0; |
| rc = sessionTableInfo(0, db, zFrom, zTbl, &nCol, 0, &azCol, 0, &abPK, |
| pSession->bImplicitPK ? &bRowid : 0 |
| ); |
| if( rc==SQLITE_OK ){ |
| if( pTo->nCol!=nCol ){ |
| bMismatch = 1; |
| }else{ |
| int i; |
| for(i=0; i<nCol; i++){ |
| if( pTo->abPK[i]!=abPK[i] ) bMismatch = 1; |
| if( sqlite3_stricmp(azCol[i], pTo->azCol[i]) ) bMismatch = 1; |
| if( abPK[i] ) bHasPk = 1; |
| } |
| } |
| } |
| sqlite3_free((char*)azCol); |
| if( bMismatch ){ |
| if( pzErrMsg ){ |
| *pzErrMsg = sqlite3_mprintf("table schemas do not match"); |
| } |
| rc = SQLITE_SCHEMA; |
| } |
| if( bHasPk==0 ){ |
| /* Ignore tables with no primary keys */ |
| goto diff_out; |
| } |
| } |
| |
| if( rc==SQLITE_OK ){ |
| zExpr = sessionExprComparePK(pTo->nCol, |
| zDb, zFrom, pTo->zName, pTo->azCol, pTo->abPK |
| ); |
| } |
| |
| /* Find new rows */ |
| if( rc==SQLITE_OK ){ |
| rc = sessionDiffFindNew(SQLITE_INSERT, pSession, pTo, zDb, zFrom, zExpr); |
| } |
| |
| /* Find old rows */ |
| if( rc==SQLITE_OK ){ |
| rc = sessionDiffFindNew(SQLITE_DELETE, pSession, pTo, zFrom, zDb, zExpr); |
| } |
| |
| /* Find modified rows */ |
| if( rc==SQLITE_OK ){ |
| rc = sessionDiffFindModified(pSession, pTo, zFrom, zExpr); |
| } |
| |
| sqlite3_free(zExpr); |
| } |
| |
| diff_out: |
| sessionPreupdateHooks(pSession); |
| sqlite3_mutex_leave(sqlite3_db_mutex(pSession->db)); |
| return rc; |
| } |
| |
| /* |
| ** Create a session object. This session object will record changes to |
| ** database zDb attached to connection db. |
| */ |
| int sqlite3session_create( |
| sqlite3 *db, /* Database handle */ |
| const char *zDb, /* Name of db (e.g. "main") */ |
| sqlite3_session **ppSession /* OUT: New session object */ |
| ){ |
| sqlite3_session *pNew; /* Newly allocated session object */ |
| sqlite3_session *pOld; /* Session object already attached to db */ |
| int nDb = sqlite3Strlen30(zDb); /* Length of zDb in bytes */ |
| |
| /* Zero the output value in case an error occurs. */ |
| *ppSession = 0; |
| |
| /* Allocate and populate the new session object. */ |
| pNew = (sqlite3_session *)sqlite3_malloc64(sizeof(sqlite3_session) + nDb + 1); |
| if( !pNew ) return SQLITE_NOMEM; |
| memset(pNew, 0, sizeof(sqlite3_session)); |
| pNew->db = db; |
| pNew->zDb = (char *)&pNew[1]; |
| pNew->bEnable = 1; |
| memcpy(pNew->zDb, zDb, nDb+1); |
| sessionPreupdateHooks(pNew); |
| |
| /* Add the new session object to the linked list of session objects |
| ** attached to database handle $db. Do this under the cover of the db |
| ** handle mutex. */ |
| sqlite3_mutex_enter(sqlite3_db_mutex(db)); |
| pOld = (sqlite3_session*)sqlite3_preupdate_hook(db, xPreUpdate, (void*)pNew); |
| pNew->pNext = pOld; |
| sqlite3_mutex_leave(sqlite3_db_mutex(db)); |
| |
| *ppSession = pNew; |
| return SQLITE_OK; |
| } |
| |
| /* |
| ** Free the list of table objects passed as the first argument. The contents |
| ** of the changed-rows hash tables are also deleted. |
| */ |
| static void sessionDeleteTable(sqlite3_session *pSession, SessionTable *pList){ |
| SessionTable *pNext; |
| SessionTable *pTab; |
| |
| for(pTab=pList; pTab; pTab=pNext){ |
| int i; |
| pNext = pTab->pNext; |
| for(i=0; i<pTab->nChange; i++){ |
| SessionChange *p; |
| SessionChange *pNextChange; |
| for(p=pTab->apChange[i]; p; p=pNextChange){ |
| pNextChange = p->pNext; |
| sessionFree(pSession, p); |
| } |
| } |
| sqlite3_finalize(pTab->pDfltStmt); |
| sessionFree(pSession, (char*)pTab->azCol); /* cast works around VC++ bug */ |
| sessionFree(pSession, pTab->apChange); |
| sessionFree(pSession, pTab); |
| } |
| } |
| |
| /* |
| ** Delete a session object previously allocated using sqlite3session_create(). |
| */ |
| void sqlite3session_delete(sqlite3_session *pSession){ |
| sqlite3 *db = pSession->db; |
| sqlite3_session *pHead; |
| sqlite3_session **pp; |
| |
| /* Unlink the session from the linked list of sessions attached to the |
| ** database handle. Hold the db mutex while doing so. */ |
| sqlite3_mutex_enter(sqlite3_db_mutex(db)); |
| pHead = (sqlite3_session*)sqlite3_preupdate_hook(db, 0, 0); |
| for(pp=&pHead; ALWAYS((*pp)!=0); pp=&((*pp)->pNext)){ |
| if( (*pp)==pSession ){ |
| *pp = (*pp)->pNext; |
| if( pHead ) sqlite3_preupdate_hook(db, xPreUpdate, (void*)pHead); |
| break; |
| } |
| } |
| sqlite3_mutex_leave(sqlite3_db_mutex(db)); |
| sqlite3ValueFree(pSession->pZeroBlob); |
| |
| /* Delete all attached table objects. And the contents of their |
| ** associated hash-tables. */ |
| sessionDeleteTable(pSession, pSession->pTable); |
| |
| /* Free the session object. */ |
| sqlite3_free(pSession); |
| } |
| |
| /* |
| ** Set a table filter on a Session Object. |
| */ |
| void sqlite3session_table_filter( |
| sqlite3_session *pSession, |
| int(*xFilter)(void*, const char*), |
| void *pCtx /* First argument passed to xFilter */ |
| ){ |
| pSession->bAutoAttach = 1; |
| pSession->pFilterCtx = pCtx; |
| pSession->xTableFilter = xFilter; |
| } |
| |
| /* |
| ** Attach a table to a session. All subsequent changes made to the table |
| ** while the session object is enabled will be recorded. |
| ** |
| ** Only tables that have a PRIMARY KEY defined may be attached. It does |
| ** not matter if the PRIMARY KEY is an "INTEGER PRIMARY KEY" (rowid alias) |
| ** or not. |
| */ |
| int sqlite3session_attach( |
| sqlite3_session *pSession, /* Session object */ |
| const char *zName /* Table name */ |
| ){ |
| int rc = SQLITE_OK; |
| sqlite3_mutex_enter(sqlite3_db_mutex(pSession->db)); |
| |
| if( !zName ){ |
| pSession->bAutoAttach = 1; |
| }else{ |
| SessionTable *pTab; /* New table object (if required) */ |
| int nName; /* Number of bytes in string zName */ |
| |
| /* First search for an existing entry. If one is found, this call is |
| ** a no-op. Return early. */ |
| nName = sqlite3Strlen30(zName); |
| for(pTab=pSession->pTable; pTab; pTab=pTab->pNext){ |
| if( 0==sqlite3_strnicmp(pTab->zName, zName, nName+1) ) break; |
| } |
| |
| if( !pTab ){ |
| /* Allocate new SessionTable object. */ |
| int nByte = sizeof(SessionTable) + nName + 1; |
| pTab = (SessionTable*)sessionMalloc64(pSession, nByte); |
| if( !pTab ){ |
| rc = SQLITE_NOMEM; |
| }else{ |
| /* Populate the new SessionTable object and link it into the list. |
| ** The new object must be linked onto the end of the list, not |
| ** simply added to the start of it in order to ensure that tables |
| ** appear in the correct order when a changeset or patchset is |
| ** eventually generated. */ |
| SessionTable **ppTab; |
| memset(pTab, 0, sizeof(SessionTable)); |
| pTab->zName = (char *)&pTab[1]; |
| memcpy(pTab->zName, zName, nName+1); |
| for(ppTab=&pSession->pTable; *ppTab; ppTab=&(*ppTab)->pNext); |
| *ppTab = pTab; |
| } |
| } |
| } |
| |
| sqlite3_mutex_leave(sqlite3_db_mutex(pSession->db)); |
| return rc; |
| } |
| |
| /* |
| ** Append the value passed as the second argument to the buffer passed |
| ** as the first. |
| ** |
| ** This function is a no-op if *pRc is non-zero when it is called. |
| ** Otherwise, if an error occurs, *pRc is set to an SQLite error code |
| ** before returning. |
| */ |
| static void sessionAppendValue(SessionBuffer *p, sqlite3_value *pVal, int *pRc){ |
| int rc = *pRc; |
| if( rc==SQLITE_OK ){ |
| sqlite3_int64 nByte = 0; |
| rc = sessionSerializeValue(0, pVal, &nByte); |
| sessionBufferGrow(p, nByte, &rc); |
| if( rc==SQLITE_OK ){ |
| rc = sessionSerializeValue(&p->aBuf[p->nBuf], pVal, 0); |
| p->nBuf += nByte; |
| }else{ |
| *pRc = rc; |
| } |
| } |
| } |
| |
| /* |
| ** This function is a no-op if *pRc is other than SQLITE_OK when it is |
| ** called. Otherwise, append a single byte to the buffer. |
| ** |
| ** If an OOM condition is encountered, set *pRc to SQLITE_NOMEM before |
| ** returning. |
| */ |
| static void sessionAppendByte(SessionBuffer *p, u8 v, int *pRc){ |
| if( 0==sessionBufferGrow(p, 1, pRc) ){ |
| p->aBuf[p->nBuf++] = v; |
| } |
| } |
| |
| /* |
| ** This function is a no-op if *pRc is other than SQLITE_OK when it is |
| ** called. Otherwise, append a single varint to the buffer. |
| ** |
| ** If an OOM condition is encountered, set *pRc to SQLITE_NOMEM before |
| ** returning. |
| */ |
| static void sessionAppendVarint(SessionBuffer *p, int v, int *pRc){ |
| if( 0==sessionBufferGrow(p, 9, pRc) ){ |
| p->nBuf += sessionVarintPut(&p->aBuf[p->nBuf], v); |
| } |
| } |
| |
| /* |
| ** This function is a no-op if *pRc is other than SQLITE_OK when it is |
| ** called. Otherwise, append a blob of data to the buffer. |
| ** |
| ** If an OOM condition is encountered, set *pRc to SQLITE_NOMEM before |
| ** returning. |
| */ |
| static void sessionAppendBlob( |
| SessionBuffer *p, |
| const u8 *aBlob, |
| int nBlob, |
| int *pRc |
| ){ |
| if( nBlob>0 && 0==sessionBufferGrow(p, nBlob, pRc) ){ |
| memcpy(&p->aBuf[p->nBuf], aBlob, nBlob); |
| p->nBuf += nBlob; |
| } |
| } |
| |
| /* |
| ** This function is a no-op if *pRc is other than SQLITE_OK when it is |
| ** called. Otherwise, append the string representation of integer iVal |
| ** to the buffer. No nul-terminator is written. |
| ** |
| ** If an OOM condition is encountered, set *pRc to SQLITE_NOMEM before |
| ** returning. |
| */ |
| static void sessionAppendInteger( |
| SessionBuffer *p, /* Buffer to append to */ |
| int iVal, /* Value to write the string rep. of */ |
| int *pRc /* IN/OUT: Error code */ |
| ){ |
| char aBuf[24]; |
| sqlite3_snprintf(sizeof(aBuf)-1, aBuf, "%d", iVal); |
| sessionAppendStr(p, aBuf, pRc); |
| } |
| |
| /* |
| ** This function is a no-op if *pRc is other than SQLITE_OK when it is |
| ** called. Otherwise, append the string zStr enclosed in quotes (") and |
| ** with any embedded quote characters escaped to the buffer. No |
| ** nul-terminator byte is written. |
| ** |
| ** If an OOM condition is encountered, set *pRc to SQLITE_NOMEM before |
| ** returning. |
| */ |
| static void sessionAppendIdent( |
| SessionBuffer *p, /* Buffer to a append to */ |
| const char *zStr, /* String to quote, escape and append */ |
| int *pRc /* IN/OUT: Error code */ |
| ){ |
| int nStr = sqlite3Strlen30(zStr)*2 + 2 + 2; |
| if( 0==sessionBufferGrow(p, nStr, pRc) ){ |
| char *zOut = (char *)&p->aBuf[p->nBuf]; |
| const char *zIn = zStr; |
| *zOut++ = '"'; |
| while( *zIn ){ |
| if( *zIn=='"' ) *zOut++ = '"'; |
| *zOut++ = *(zIn++); |
| } |
| *zOut++ = '"'; |
| p->nBuf = (int)((u8 *)zOut - p->aBuf); |
| p->aBuf[p->nBuf] = 0x00; |
| } |
| } |
| |
| /* |
| ** This function is a no-op if *pRc is other than SQLITE_OK when it is |
| ** called. Otherwse, it appends the serialized version of the value stored |
| ** in column iCol of the row that SQL statement pStmt currently points |
| ** to to the buffer. |
| */ |
| static void sessionAppendCol( |
| SessionBuffer *p, /* Buffer to append to */ |
| sqlite3_stmt *pStmt, /* Handle pointing to row containing value */ |
| int iCol, /* Column to read value from */ |
| int *pRc /* IN/OUT: Error code */ |
| ){ |
| if( *pRc==SQLITE_OK ){ |
| int eType = sqlite3_column_type(pStmt, iCol); |
| sessionAppendByte(p, (u8)eType, pRc); |
| if( eType==SQLITE_INTEGER || eType==SQLITE_FLOAT ){ |
| sqlite3_int64 i; |
| u8 aBuf[8]; |
| if( eType==SQLITE_INTEGER ){ |
| i = sqlite3_column_int64(pStmt, iCol); |
| }else{ |
| double r = sqlite3_column_double(pStmt, iCol); |
| memcpy(&i, &r, 8); |
| } |
| sessionPutI64(aBuf, i); |
| sessionAppendBlob(p, aBuf, 8, pRc); |
| } |
| if( eType==SQLITE_BLOB || eType==SQLITE_TEXT ){ |
| u8 *z; |
| int nByte; |
| if( eType==SQLITE_BLOB ){ |
| z = (u8 *)sqlite3_column_blob(pStmt, iCol); |
| }else{ |
| z = (u8 *)sqlite3_column_text(pStmt, iCol); |
| } |
| nByte = sqlite3_column_bytes(pStmt, iCol); |
| if( z || (eType==SQLITE_BLOB && nByte==0) ){ |
| sessionAppendVarint(p, nByte, pRc); |
| sessionAppendBlob(p, z, nByte, pRc); |
| }else{ |
| *pRc = SQLITE_NOMEM; |
| } |
| } |
| } |
| } |
| |
| /* |
| ** |
| ** This function appends an update change to the buffer (see the comments |
| ** under "CHANGESET FORMAT" at the top of the file). An update change |
| ** consists of: |
| ** |
| ** 1 byte: SQLITE_UPDATE (0x17) |
| ** n bytes: old.* record (see RECORD FORMAT) |
| ** m bytes: new.* record (see RECORD FORMAT) |
| ** |
| ** The SessionChange object passed as the third argument contains the |
| ** values that were stored in the row when the session began (the old.* |
| ** values). The statement handle passed as the second argument points |
| ** at the current version of the row (the new.* values). |
| ** |
| ** If all of the old.* values are equal to their corresponding new.* value |
| ** (i.e. nothing has changed), then no data at all is appended to the buffer. |
| ** |
| ** Otherwise, the old.* record contains all primary key values and the |
| ** original values of any fields that have been modified. The new.* record |
| ** contains the new values of only those fields that have been modified. |
| */ |
| static int sessionAppendUpdate( |
| SessionBuffer *pBuf, /* Buffer to append to */ |
| int bPatchset, /* True for "patchset", 0 for "changeset" */ |
| sqlite3_stmt *pStmt, /* Statement handle pointing at new row */ |
| SessionChange *p, /* Object containing old values */ |
| u8 *abPK /* Boolean array - true for PK columns */ |
| ){ |
| int rc = SQLITE_OK; |
| SessionBuffer buf2 = {0,0,0}; /* Buffer to accumulate new.* record in */ |
| int bNoop = 1; /* Set to zero if any values are modified */ |
| int nRewind = pBuf->nBuf; /* Set to zero if any values are modified */ |
| int i; /* Used to iterate through columns */ |
| u8 *pCsr = p->aRecord; /* Used to iterate through old.* values */ |
| |
| assert( abPK!=0 ); |
| sessionAppendByte(pBuf, SQLITE_UPDATE, &rc); |
| sessionAppendByte(pBuf, p->bIndirect, &rc); |
| for(i=0; i<sqlite3_column_count(pStmt); i++){ |
| int bChanged = 0; |
| int nAdvance; |
| int eType = *pCsr; |
| switch( eType ){ |
| case SQLITE_NULL: |
| nAdvance = 1; |
| if( sqlite3_column_type(pStmt, i)!=SQLITE_NULL ){ |
| bChanged = 1; |
| } |
| break; |
| |
| case SQLITE_FLOAT: |
| case SQLITE_INTEGER: { |
| nAdvance = 9; |
| if( eType==sqlite3_column_type(pStmt, i) ){ |
| sqlite3_int64 iVal = sessionGetI64(&pCsr[1]); |
| if( eType==SQLITE_INTEGER ){ |
| if( iVal==sqlite3_column_int64(pStmt, i) ) break; |
| }else{ |
| double dVal; |
| memcpy(&dVal, &iVal, 8); |
| if( dVal==sqlite3_column_double(pStmt, i) ) break; |
| } |
| } |
| bChanged = 1; |
| break; |
| } |
| |
| default: { |
| int n; |
| int nHdr = 1 + sessionVarintGet(&pCsr[1], &n); |
| assert( eType==SQLITE_TEXT || eType==SQLITE_BLOB ); |
| nAdvance = nHdr + n; |
| if( eType==sqlite3_column_type(pStmt, i) |
| && n==sqlite3_column_bytes(pStmt, i) |
| && (n==0 || 0==memcmp(&pCsr[nHdr], sqlite3_column_blob(pStmt, i), n)) |
| ){ |
| break; |
| } |
| bChanged = 1; |
| } |
| } |
| |
| /* If at least one field has been modified, this is not a no-op. */ |
| if( bChanged ) bNoop = 0; |
| |
| /* Add a field to the old.* record. This is omitted if this module is |
| ** currently generating a patchset. */ |
| if( bPatchset==0 ){ |
| if( bChanged || abPK[i] ){ |
| sessionAppendBlob(pBuf, pCsr, nAdvance, &rc); |
| }else{ |
| sessionAppendByte(pBuf, 0, &rc); |
| } |
| } |
| |
| /* Add a field to the new.* record. Or the only record if currently |
| ** generating a patchset. */ |
| if( bChanged || (bPatchset && abPK[i]) ){ |
| sessionAppendCol(&buf2, pStmt, i, &rc); |
| }else{ |
| sessionAppendByte(&buf2, 0, &rc); |
| } |
| |
| pCsr += nAdvance; |
| } |
| |
| if( bNoop ){ |
| pBuf->nBuf = nRewind; |
| }else{ |
| sessionAppendBlob(pBuf, buf2.aBuf, buf2.nBuf, &rc); |
| } |
| sqlite3_free(buf2.aBuf); |
| |
| return rc; |
| } |
| |
| /* |
| ** Append a DELETE change to the buffer passed as the first argument. Use |
| ** the changeset format if argument bPatchset is zero, or the patchset |
| ** format otherwise. |
| */ |
| static int sessionAppendDelete( |
| SessionBuffer *pBuf, /* Buffer to append to */ |
| int bPatchset, /* True for "patchset", 0 for "changeset" */ |
| SessionChange *p, /* Object containing old values */ |
| int nCol, /* Number of columns in table */ |
| u8 *abPK /* Boolean array - true for PK columns */ |
| ){ |
| int rc = SQLITE_OK; |
| |
| sessionAppendByte(pBuf, SQLITE_DELETE, &rc); |
| sessionAppendByte(pBuf, p->bIndirect, &rc); |
| |
| if( bPatchset==0 ){ |
| sessionAppendBlob(pBuf, p->aRecord, p->nRecord, &rc); |
| }else{ |
| int i; |
| u8 *a = p->aRecord; |
| for(i=0; i<nCol; i++){ |
| u8 *pStart = a; |
| int eType = *a++; |
| |
| switch( eType ){ |
| case 0: |
| case SQLITE_NULL: |
| assert( abPK[i]==0 ); |
| break; |
| |
| case SQLITE_FLOAT: |
| case SQLITE_INTEGER: |
| a += 8; |
| break; |
| |
| default: { |
| int n; |
| a += sessionVarintGet(a, &n); |
| a += n; |
| break; |
| } |
| } |
| if( abPK[i] ){ |
| sessionAppendBlob(pBuf, pStart, (int)(a-pStart), &rc); |
| } |
| } |
| assert( (a - p->aRecord)==p->nRecord ); |
| } |
| |
| return rc; |
| } |
| |
| /* |
| ** Formulate and prepare a SELECT statement to retrieve a row from table |
| ** zTab in database zDb based on its primary key. i.e. |
| ** |
| ** SELECT *, <noop-test> FROM zDb.zTab WHERE (pk1, pk2,...) IS (?1, ?2,...) |
| ** |
| ** where <noop-test> is: |
| ** |
| ** 1 AND (?A OR ?1 IS <column>) AND ... |
| ** |
| ** for each non-pk <column>. |
| */ |
| static int sessionSelectStmt( |
| sqlite3 *db, /* Database handle */ |
| int bIgnoreNoop, |
| const char *zDb, /* Database name */ |
| const char *zTab, /* Table name */ |
| int bRowid, |
| int nCol, /* Number of columns in table */ |
| const char **azCol, /* Names of table columns */ |
| u8 *abPK, /* PRIMARY KEY array */ |
| sqlite3_stmt **ppStmt /* OUT: Prepared SELECT statement */ |
| ){ |
| int rc = SQLITE_OK; |
| char *zSql = 0; |
| const char *zSep = ""; |
| const char *zCols = bRowid ? SESSIONS_ROWID ", *" : "*"; |
| int nSql = -1; |
| int i; |
| |
| SessionBuffer nooptest = {0, 0, 0}; |
| SessionBuffer pkfield = {0, 0, 0}; |
| SessionBuffer pkvar = {0, 0, 0}; |
| |
| sessionAppendStr(&nooptest, ", 1", &rc); |
| |
| if( 0==sqlite3_stricmp("sqlite_stat1", zTab) ){ |
| sessionAppendStr(&nooptest, " AND (?6 OR ?3 IS stat)", &rc); |
| sessionAppendStr(&pkfield, "tbl, idx", &rc); |
| sessionAppendStr(&pkvar, |
| "?1, (CASE WHEN ?2=X'' THEN NULL ELSE ?2 END)", &rc |
| ); |
| zCols = "tbl, ?2, stat"; |
| }else{ |
| for(i=0; i<nCol; i++){ |
| if( abPK[i] ){ |
| sessionAppendStr(&pkfield, zSep, &rc); |
| sessionAppendStr(&pkvar, zSep, &rc); |
| zSep = ", "; |
| sessionAppendIdent(&pkfield, azCol[i], &rc); |
| sessionAppendPrintf(&pkvar, &rc, "?%d", i+1); |
| }else{ |
| sessionAppendPrintf(&nooptest, &rc, |
| " AND (?%d OR ?%d IS %w.%w)", i+1+nCol, i+1, zTab, azCol[i] |
| ); |
| } |
| } |
| } |
| |
| if( rc==SQLITE_OK ){ |
| zSql = sqlite3_mprintf( |
| "SELECT %s%s FROM %Q.%Q WHERE (%s) IS (%s)", |
| zCols, (bIgnoreNoop ? (char*)nooptest.aBuf : ""), |
| zDb, zTab, (char*)pkfield.aBuf, (char*)pkvar.aBuf |
| ); |
| if( zSql==0 ) rc = SQLITE_NOMEM; |
| } |
| |
| #if 0 |
| if( 0==sqlite3_stricmp("sqlite_stat1", zTab) ){ |
| zSql = sqlite3_mprintf( |
| "SELECT tbl, ?2, stat FROM %Q.sqlite_stat1 WHERE tbl IS ?1 AND " |
| "idx IS (CASE WHEN ?2=X'' THEN NULL ELSE ?2 END)", zDb |
| ); |
| if( zSql==0 ) rc = SQLITE_NOMEM; |
| }else{ |
| const char *zSep = ""; |
| SessionBuffer buf = {0, 0, 0}; |
| |
| sessionAppendStr(&buf, "SELECT * FROM ", &rc); |
| sessionAppendIdent(&buf, zDb, &rc); |
| sessionAppendStr(&buf, ".", &rc); |
| sessionAppendIdent(&buf, zTab, &rc); |
| sessionAppendStr(&buf, " WHERE ", &rc); |
| for(i=0; i<nCol; i++){ |
| if( abPK[i] ){ |
| sessionAppendStr(&buf, zSep, &rc); |
| sessionAppendIdent(&buf, azCol[i], &rc); |
| sessionAppendStr(&buf, " IS ?", &rc); |
| sessionAppendInteger(&buf, i+1, &rc); |
| zSep = " AND "; |
| } |
| } |
| zSql = (char*)buf.aBuf; |
| nSql = buf.nBuf; |
| } |
| #endif |
| |
| if( rc==SQLITE_OK ){ |
| rc = sqlite3_prepare_v2(db, zSql, nSql, ppStmt, 0); |
| } |
| sqlite3_free(zSql); |
| sqlite3_free(nooptest.aBuf); |
| sqlite3_free(pkfield.aBuf); |
| sqlite3_free(pkvar.aBuf); |
| return rc; |
| } |
| |
| /* |
| ** Bind the PRIMARY KEY values from the change passed in argument pChange |
| ** to the SELECT statement passed as the first argument. The SELECT statement |
| ** is as prepared by function sessionSelectStmt(). |
| ** |
| ** Return SQLITE_OK if all PK values are successfully bound, or an SQLite |
| ** error code (e.g. SQLITE_NOMEM) otherwise. |
| */ |
| static int sessionSelectBind( |
| sqlite3_stmt *pSelect, /* SELECT from sessionSelectStmt() */ |
| int nCol, /* Number of columns in table */ |
| u8 *abPK, /* PRIMARY KEY array */ |
| SessionChange *pChange /* Change structure */ |
| ){ |
| int i; |
| int rc = SQLITE_OK; |
| u8 *a = pChange->aRecord; |
| |
| for(i=0; i<nCol && rc==SQLITE_OK; i++){ |
| int eType = *a++; |
| |
| switch( eType ){ |
| case 0: |
| case SQLITE_NULL: |
| assert( abPK[i]==0 ); |
| break; |
| |
| case SQLITE_INTEGER: { |
| if( abPK[i] ){ |
| i64 iVal = sessionGetI64(a); |
| rc = sqlite3_bind_int64(pSelect, i+1, iVal); |
| } |
| a += 8; |
| break; |
| } |
| |
| case SQLITE_FLOAT: { |
| if( abPK[i] ){ |
| double rVal; |
| i64 iVal = sessionGetI64(a); |
| memcpy(&rVal, &iVal, 8); |
| rc = sqlite3_bind_double(pSelect, i+1, rVal); |
| } |
| a += 8; |
| break; |
| } |
| |
| case SQLITE_TEXT: { |
| int n; |
| a += sessionVarintGet(a, &n); |
| if( abPK[i] ){ |
| rc = sqlite3_bind_text(pSelect, i+1, (char *)a, n, SQLITE_TRANSIENT); |
| } |
| a += n; |
| break; |
| } |
| |
| default: { |
| int n; |
| assert( eType==SQLITE_BLOB ); |
| a += sessionVarintGet(a, &n); |
| if( abPK[i] ){ |
| rc = sqlite3_bind_blob(pSelect, i+1, a, n, SQLITE_TRANSIENT); |
| } |
| a += n; |
| break; |
| } |
| } |
| } |
| |
| return rc; |
| } |
| |
| /* |
| ** This function is a no-op if *pRc is set to other than SQLITE_OK when it |
| ** is called. Otherwise, append a serialized table header (part of the binary |
| ** changeset format) to buffer *pBuf. If an error occurs, set *pRc to an |
| ** SQLite error code before returning. |
| */ |
| static void sessionAppendTableHdr( |
| SessionBuffer *pBuf, /* Append header to this buffer */ |
| int bPatchset, /* Use the patchset format if true */ |
| SessionTable *pTab, /* Table object to append header for */ |
| int *pRc /* IN/OUT: Error code */ |
| ){ |
| /* Write a table header */ |
| sessionAppendByte(pBuf, (bPatchset ? 'P' : 'T'), pRc); |
| sessionAppendVarint(pBuf, pTab->nCol, pRc); |
| sessionAppendBlob(pBuf, pTab->abPK, pTab->nCol, pRc); |
| sessionAppendBlob(pBuf, (u8 *)pTab->zName, (int)strlen(pTab->zName)+1, pRc); |
| } |
| |
| /* |
| ** Generate either a changeset (if argument bPatchset is zero) or a patchset |
| ** (if it is non-zero) based on the current contents of the session object |
| ** passed as the first argument. |
| ** |
| ** If no error occurs, SQLITE_OK is returned and the new changeset/patchset |
| ** stored in output variables *pnChangeset and *ppChangeset. Or, if an error |
| ** occurs, an SQLite error code is returned and both output variables set |
| ** to 0. |
| */ |
| static int sessionGenerateChangeset( |
| sqlite3_session *pSession, /* Session object */ |
| int bPatchset, /* True for patchset, false for changeset */ |
| int (*xOutput)(void *pOut, const void *pData, int nData), |
| void *pOut, /* First argument for xOutput */ |
| int *pnChangeset, /* OUT: Size of buffer at *ppChangeset */ |
| void **ppChangeset /* OUT: Buffer containing changeset */ |
| ){ |
| sqlite3 *db = pSession->db; /* Source database handle */ |
| SessionTable *pTab; /* Used to iterate through attached tables */ |
| SessionBuffer buf = {0,0,0}; /* Buffer in which to accumlate changeset */ |
| int rc; /* Return code */ |
| |
| assert( xOutput==0 || (pnChangeset==0 && ppChangeset==0) ); |
| assert( xOutput!=0 || (pnChangeset!=0 && ppChangeset!=0) ); |
| |
| /* Zero the output variables in case an error occurs. If this session |
| ** object is already in the error state (sqlite3_session.rc != SQLITE_OK), |
| ** this call will be a no-op. */ |
| if( xOutput==0 ){ |
| assert( pnChangeset!=0 && ppChangeset!=0 ); |
| *pnChangeset = 0; |
| *ppChangeset = 0; |
| } |
| |