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 21 #ifndef SQLITE_OMIT_GET_TABLE 22 23 /* 24 ** This structure is used to pass data from sqlite3_get_table() through 25 ** to the callback function is uses to build the result. 26 */ 27 typedef struct TabResult { 28 char **azResult; /* Accumulated output */ 29 char *zErrMsg; /* Error message text, if an error occurs */ 30 u32 nAlloc; /* Slots allocated for azResult[] */ 31 u32 nRow; /* Number of rows in the result */ 32 u32 nColumn; /* Number of columns in the result */ 33 u32 nData; /* Slots used in azResult[]. (nRow+1)*nColumn */ 34 int rc; /* Return code from sqlite3_exec() */ 35 } TabResult; 36 37 /* 38 ** This routine is called once for each row in the result table. Its job 39 ** is to fill in the TabResult structure appropriately, allocating new 40 ** memory as necessary. 41 */ 42 static int sqlite3_get_table_cb(void *pArg, int nCol, char **argv, char **colv){ 43 TabResult *p = (TabResult*)pArg; /* Result accumulator */ 44 int need; /* Slots needed in p->azResult[] */ 45 int i; /* Loop counter */ 46 char *z; /* A single column of result */ 47 48 /* Make sure there is enough space in p->azResult to hold everything 49 ** we need to remember from this invocation of the callback. 50 */ 51 if( p->nRow==0 && argv!=0 ){ 52 need = nCol*2; 53 }else{ 54 need = nCol; 55 } 56 if( p->nData + need > p->nAlloc ){ 57 char **azNew; 58 p->nAlloc = p->nAlloc*2 + need; 59 azNew = sqlite3Realloc( p->azResult, sizeof(char*)*p->nAlloc ); 60 if( azNew==0 ) goto malloc_failed; 61 p->azResult = azNew; 62 } 63 64 /* If this is the first row, then generate an extra row containing 65 ** the names of all columns. 66 */ 67 if( p->nRow==0 ){ 68 p->nColumn = nCol; 69 for(i=0; i<nCol; i++){ 70 z = sqlite3_mprintf("%s", colv[i]); 71 if( z==0 ) goto malloc_failed; 72 p->azResult[p->nData++] = z; 73 } 74 }else if( (int)p->nColumn!=nCol ){ 75 sqlite3_free(p->zErrMsg); 76 p->zErrMsg = sqlite3_mprintf( 77 "sqlite3_get_table() called with two or more incompatible queries" 78 ); 79 p->rc = SQLITE_ERROR; 80 return 1; 81 } 82 83 /* Copy over the row data 84 */ 85 if( argv!=0 ){ 86 for(i=0; i<nCol; i++){ 87 if( argv[i]==0 ){ 88 z = 0; 89 }else{ 90 int n = sqlite3Strlen30(argv[i])+1; 91 z = sqlite3_malloc64( n ); 92 if( z==0 ) goto malloc_failed; 93 memcpy(z, argv[i], n); 94 } 95 p->azResult[p->nData++] = z; 96 } 97 p->nRow++; 98 } 99 return 0; 100 101 malloc_failed: 102 p->rc = SQLITE_NOMEM_BKPT; 103 return 1; 104 } 105 106 /* 107 ** Query the database. But instead of invoking a callback for each row, 108 ** malloc() for space to hold the result and return the entire results 109 ** at the conclusion of the call. 110 ** 111 ** The result that is written to ***pazResult is held in memory obtained 112 ** from malloc(). But the caller cannot free this memory directly. 113 ** Instead, the entire table should be passed to sqlite3_free_table() when 114 ** the calling procedure is finished using it. 115 */ 116 int sqlite3_get_table( 117 sqlite3 *db, /* The database on which the SQL executes */ 118 const char *zSql, /* The SQL to be executed */ 119 char ***pazResult, /* Write the result table here */ 120 int *pnRow, /* Write the number of rows in the result here */ 121 int *pnColumn, /* Write the number of columns of result here */ 122 char **pzErrMsg /* Write error messages here */ 123 ){ 124 int rc; 125 TabResult res; 126 127 #ifdef SQLITE_ENABLE_API_ARMOR 128 if( !sqlite3SafetyCheckOk(db) || pazResult==0 ) return SQLITE_MISUSE_BKPT; 129 #endif 130 *pazResult = 0; 131 if( pnColumn ) *pnColumn = 0; 132 if( pnRow ) *pnRow = 0; 133 if( pzErrMsg ) *pzErrMsg = 0; 134 res.zErrMsg = 0; 135 res.nRow = 0; 136 res.nColumn = 0; 137 res.nData = 1; 138 res.nAlloc = 20; 139 res.rc = SQLITE_OK; 140 res.azResult = sqlite3_malloc64(sizeof(char*)*res.nAlloc ); 141 if( res.azResult==0 ){ 142 db->errCode = SQLITE_NOMEM; 143 return SQLITE_NOMEM_BKPT; 144 } 145 res.azResult[0] = 0; 146 rc = sqlite3_exec(db, zSql, sqlite3_get_table_cb, &res, pzErrMsg); 147 assert( sizeof(res.azResult[0])>= sizeof(res.nData) ); 148 res.azResult[0] = SQLITE_INT_TO_PTR(res.nData); 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 sqlite3_free(res.zErrMsg); 157 } 158 db->errCode = res.rc; /* Assume 32-bit assignment is atomic */ 159 return res.rc; 160 } 161 sqlite3_free(res.zErrMsg); 162 if( rc!=SQLITE_OK ){ 163 sqlite3_free_table(&res.azResult[1]); 164 return rc; 165 } 166 if( res.nAlloc>res.nData ){ 167 char **azNew; 168 azNew = sqlite3Realloc( res.azResult, sizeof(char*)*res.nData ); 169 if( azNew==0 ){ 170 sqlite3_free_table(&res.azResult[1]); 171 db->errCode = SQLITE_NOMEM; 172 return SQLITE_NOMEM_BKPT; 173 } 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; 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 sqlite3_get_table() */ 187 ){ 188 if( azResult ){ 189 int i, n; 190 azResult--; 191 assert( azResult!=0 ); 192 n = SQLITE_PTR_TO_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