| /* |
| ** 2014-11-10 |
| ** |
| ** The author disclaims copyright to this source code. In place of |
| ** a legal notice, here is a blessing: |
| ** |
| ** May you do good and not evil. |
| ** May you find forgiveness for yourself and forgive others. |
| ** May you share freely, never taking more than you give. |
| ** |
| ****************************************************************************** |
| ** |
| ** This SQLite extension implements SQL function eval() which runs |
| ** SQL statements recursively. |
| */ |
| #include "sqlite3ext.h" |
| SQLITE_EXTENSION_INIT1 |
| #include <string.h> |
| |
| /* |
| ** Structure used to accumulate the output |
| */ |
| struct EvalResult { |
| char *z; /* Accumulated output */ |
| const char *zSep; /* Separator */ |
| int szSep; /* Size of the separator string */ |
| sqlite3_int64 nAlloc; /* Number of bytes allocated for z[] */ |
| sqlite3_int64 nUsed; /* Number of bytes of z[] actually used */ |
| }; |
| |
| /* |
| ** Callback from sqlite_exec() for the eval() function. |
| */ |
| static int callback(void *pCtx, int argc, char **argv, char **colnames){ |
| struct EvalResult *p = (struct EvalResult*)pCtx; |
| int i; |
| if( argv==0 ) return 0; |
| for(i=0; i<argc; i++){ |
| const char *z = argv[i] ? argv[i] : ""; |
| size_t sz = strlen(z); |
| if( (sqlite3_int64)sz+p->nUsed+p->szSep+1 > p->nAlloc ){ |
| char *zNew; |
| p->nAlloc = p->nAlloc*2 + sz + p->szSep + 1; |
| /* Using sqlite3_realloc64() would be better, but it is a recent |
| ** addition and will cause a segfault if loaded by an older version |
| ** of SQLite. */ |
| zNew = p->nAlloc<=0x7fffffff ? sqlite3_realloc64(p->z, p->nAlloc) : 0; |
| if( zNew==0 ){ |
| sqlite3_free(p->z); |
| memset(p, 0, sizeof(*p)); |
| return 1; |
| } |
| p->z = zNew; |
| } |
| if( p->nUsed>0 ){ |
| memcpy(&p->z[p->nUsed], p->zSep, p->szSep); |
| p->nUsed += p->szSep; |
| } |
| memcpy(&p->z[p->nUsed], z, sz); |
| p->nUsed += sz; |
| } |
| return 0; |
| } |
| |
| /* |
| ** Implementation of the eval(X) and eval(X,Y) SQL functions. |
| ** |
| ** Evaluate the SQL text in X. Return the results, using string |
| ** Y as the separator. If Y is omitted, use a single space character. |
| */ |
| static void sqlEvalFunc( |
| sqlite3_context *context, |
| int argc, |
| sqlite3_value **argv |
| ){ |
| const char *zSql; |
| sqlite3 *db; |
| char *zErr = 0; |
| int rc; |
| struct EvalResult x; |
| |
| memset(&x, 0, sizeof(x)); |
| x.zSep = " "; |
| zSql = (const char*)sqlite3_value_text(argv[0]); |
| if( zSql==0 ) return; |
| if( argc>1 ){ |
| x.zSep = (const char*)sqlite3_value_text(argv[1]); |
| if( x.zSep==0 ) return; |
| } |
| x.szSep = (int)strlen(x.zSep); |
| db = sqlite3_context_db_handle(context); |
| rc = sqlite3_exec(db, zSql, callback, &x, &zErr); |
| if( rc!=SQLITE_OK ){ |
| sqlite3_result_error(context, zErr, -1); |
| sqlite3_free(zErr); |
| }else if( x.zSep==0 ){ |
| sqlite3_result_error_nomem(context); |
| sqlite3_free(x.z); |
| }else{ |
| sqlite3_result_text(context, x.z, (int)x.nUsed, sqlite3_free); |
| } |
| } |
| |
| |
| #ifdef _WIN32 |
| __declspec(dllexport) |
| #endif |
| int sqlite3_eval_init( |
| sqlite3 *db, |
| char **pzErrMsg, |
| const sqlite3_api_routines *pApi |
| ){ |
| int rc = SQLITE_OK; |
| SQLITE_EXTENSION_INIT2(pApi); |
| (void)pzErrMsg; /* Unused parameter */ |
| rc = sqlite3_create_function(db, "eval", 1, |
| SQLITE_UTF8|SQLITE_DIRECTONLY, 0, |
| sqlEvalFunc, 0, 0); |
| if( rc==SQLITE_OK ){ |
| rc = sqlite3_create_function(db, "eval", 2, |
| SQLITE_UTF8|SQLITE_DIRECTONLY, 0, |
| sqlEvalFunc, 0, 0); |
| } |
| return rc; |
| } |