1 /* 2 ** 2001 September 15 3 ** 4 ** The author disclaims copyright to this source code. In place of 5 ** a legal notice, here is a blessing: 6 ** 7 ** May you do good and not evil. 8 ** May you find forgiveness for yourself and forgive others. 9 ** May you share freely, never taking more than you give. 10 ** 11 ************************************************************************* 12 ** This file contains the sqlite3_get_table() and sqlite3_free_table() 13 ** interface routines. These are just wrappers around the main 14 ** interface routine of sqlite3_exec(). 15 ** 16 ** These routines are in a separate files so that they will not be linked 17 ** if they are not used. 18 */ 19 #include "sqliteInt.h" 20 #include <stdlib.h> 21 #include <string.h> 22 23 #ifndef SQLITE_OMIT_GET_TABLE 24 25 /* 26 ** This structure is used to pass data from sqlite3_get_table() through 27 ** to the callback function is uses to build the result. 28 */ 29 typedef struct TabResult { 30 char **azResult; 31 char *zErrMsg; 32 int nResult; 33 int nAlloc; 34 int nRow; 35 int nColumn; 36 int nData; 37 int rc; 38 } TabResult; 39 40 /* 41 ** This routine is called once for each row in the result table. Its job 42 ** is to fill in the TabResult structure appropriately, allocating new 43 ** memory as necessary. 44 */ 45 static int sqlite3_get_table_cb(void *pArg, int nCol, char **argv, char **colv){ 46 TabResult *p = (TabResult*)pArg; 47 int need; 48 int i; 49 char *z; 50 51 /* Make sure there is enough space in p->azResult to hold everything 52 ** we need to remember from this invocation of the callback. 53 */ 54 if( p->nRow==0 && argv!=0 ){ 55 need = nCol*2; 56 }else{ 57 need = nCol; 58 } 59 if( p->nData + need >= p->nAlloc ){ 60 char **azNew; 61 p->nAlloc = p->nAlloc*2 + need + 1; 62 azNew = sqlite3_realloc( p->azResult, sizeof(char*)*p->nAlloc ); 63 if( azNew==0 ) goto malloc_failed; 64 p->azResult = azNew; 65 } 66 67 /* If this is the first row, then generate an extra row containing 68 ** the names of all columns. 69 */ 70 if( p->nRow==0 ){ 71 p->nColumn = nCol; 72 for(i=0; i<nCol; i++){ 73 if( colv[i]==0 ){ 74 z = sqlite3_mprintf(""); 75 }else{ 76 z = sqlite3_mprintf("%s", colv[i]); 77 } 78 p->azResult[p->nData++] = z; 79 } 80 }else if( p->nColumn!=nCol ){ 81 sqlite3SetString(&p->zErrMsg, 82 "sqlite3_get_table() called with two or more incompatible queries", 83 (char*)0); 84 p->rc = SQLITE_ERROR; 85 return 1; 86 } 87 88 /* Copy over the row data 89 */ 90 if( argv!=0 ){ 91 for(i=0; i<nCol; i++){ 92 if( argv[i]==0 ){ 93 z = 0; 94 }else{ 95 z = sqlite3_malloc( strlen(argv[i])+1 ); 96 if( z==0 ) goto malloc_failed; 97 strcpy(z, argv[i]); 98 } 99 p->azResult[p->nData++] = z; 100 } 101 p->nRow++; 102 } 103 return 0; 104 105 malloc_failed: 106 p->rc = SQLITE_NOMEM; 107 return 1; 108 } 109 110 /* 111 ** Query the database. But instead of invoking a callback for each row, 112 ** malloc() for space to hold the result and return the entire results 113 ** at the conclusion of the call. 114 ** 115 ** The result that is written to ***pazResult is held in memory obtained 116 ** from malloc(). But the caller cannot free this memory directly. 117 ** Instead, the entire table should be passed to sqlite3_free_table() when 118 ** the calling procedure is finished using it. 119 */ 120 int sqlite3_get_table( 121 sqlite3 *db, /* The database on which the SQL executes */ 122 const char *zSql, /* The SQL to be executed */ 123 char ***pazResult, /* Write the result table here */ 124 int *pnRow, /* Write the number of rows in the result here */ 125 int *pnColumn, /* Write the number of columns of result here */ 126 char **pzErrMsg /* Write error messages here */ 127 ){ 128 int rc; 129 TabResult res; 130 if( pazResult==0 ){ return SQLITE_ERROR; } 131 *pazResult = 0; 132 if( pnColumn ) *pnColumn = 0; 133 if( pnRow ) *pnRow = 0; 134 res.zErrMsg = 0; 135 res.nResult = 0; 136 res.nRow = 0; 137 res.nColumn = 0; 138 res.nData = 1; 139 res.nAlloc = 20; 140 res.rc = SQLITE_OK; 141 res.azResult = sqlite3_malloc( sizeof(char*)*res.nAlloc ); 142 if( res.azResult==0 ) return SQLITE_NOMEM; 143 res.azResult[0] = 0; 144 rc = sqlite3_exec(db, zSql, sqlite3_get_table_cb, &res, pzErrMsg); 145 if( res.azResult ){ 146 assert( sizeof(res.azResult[0])>= sizeof(res.nData) ); 147 res.azResult[0] = (char*)res.nData; 148 } 149 if( (rc&0xff)==SQLITE_ABORT ){ 150 sqlite3_free_table(&res.azResult[1]); 151 if( res.zErrMsg ){ 152 if( pzErrMsg ){ 153 sqlite3_free(*pzErrMsg); 154 *pzErrMsg = sqlite3_mprintf("%s",res.zErrMsg); 155 } 156 sqliteFree(res.zErrMsg); 157 } 158 db->errCode = res.rc; 159 return res.rc & db->errMask; 160 } 161 sqliteFree(res.zErrMsg); 162 if( rc!=SQLITE_OK ){ 163 sqlite3_free_table(&res.azResult[1]); 164 return rc & db->errMask; 165 } 166 if( res.nAlloc>res.nData ){ 167 char **azNew; 168 azNew = sqlite3_realloc( res.azResult, sizeof(char*)*(res.nData+1) ); 169 if( azNew==0 ){ 170 sqlite3_free_table(&res.azResult[1]); 171 return SQLITE_NOMEM; 172 } 173 res.nAlloc = res.nData+1; 174 res.azResult = azNew; 175 } 176 *pazResult = &res.azResult[1]; 177 if( pnColumn ) *pnColumn = res.nColumn; 178 if( pnRow ) *pnRow = res.nRow; 179 return rc & db->errMask; 180 } 181 182 /* 183 ** This routine frees the space the sqlite3_get_table() malloced. 184 */ 185 void sqlite3_free_table( 186 char **azResult /* Result returned from from sqlite3_get_table() */ 187 ){ 188 if( azResult ){ 189 int i, n; 190 azResult--; 191 if( azResult==0 ) return; 192 n = (int)azResult[0]; 193 for(i=1; i<n; i++){ if( azResult[i] ) sqlite3_free(azResult[i]); } 194 sqlite3_free(azResult); 195 } 196 } 197 198 #endif /* SQLITE_OMIT_GET_TABLE */ 199