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 if( z==0 ) goto malloc_failed; 79 p->azResult[p->nData++] = z; 80 } 81 }else if( p->nColumn!=nCol ){ 82 sqlite3_free(p->zErrMsg); 83 p->zErrMsg = sqlite3_mprintf( 84 "sqlite3_get_table() called with two or more incompatible queries" 85 ); 86 p->rc = SQLITE_ERROR; 87 return 1; 88 } 89 90 /* Copy over the row data 91 */ 92 if( argv!=0 ){ 93 for(i=0; i<nCol; i++){ 94 if( argv[i]==0 ){ 95 z = 0; 96 }else{ 97 int n = strlen(argv[i])+1; 98 z = sqlite3_malloc( n ); 99 if( z==0 ) goto malloc_failed; 100 memcpy(z, argv[i], n); 101 } 102 p->azResult[p->nData++] = z; 103 } 104 p->nRow++; 105 } 106 return 0; 107 108 malloc_failed: 109 p->rc = SQLITE_NOMEM; 110 return 1; 111 } 112 113 /* 114 ** Query the database. But instead of invoking a callback for each row, 115 ** malloc() for space to hold the result and return the entire results 116 ** at the conclusion of the call. 117 ** 118 ** The result that is written to ***pazResult is held in memory obtained 119 ** from malloc(). But the caller cannot free this memory directly. 120 ** Instead, the entire table should be passed to sqlite3_free_table() when 121 ** the calling procedure is finished using it. 122 */ 123 int sqlite3_get_table( 124 sqlite3 *db, /* The database on which the SQL executes */ 125 const char *zSql, /* The SQL to be executed */ 126 char ***pazResult, /* Write the result table here */ 127 int *pnRow, /* Write the number of rows in the result here */ 128 int *pnColumn, /* Write the number of columns of result here */ 129 char **pzErrMsg /* Write error messages here */ 130 ){ 131 int rc; 132 TabResult res; 133 if( pazResult==0 ){ return SQLITE_ERROR; } 134 *pazResult = 0; 135 if( pnColumn ) *pnColumn = 0; 136 if( pnRow ) *pnRow = 0; 137 res.zErrMsg = 0; 138 res.nResult = 0; 139 res.nRow = 0; 140 res.nColumn = 0; 141 res.nData = 1; 142 res.nAlloc = 20; 143 res.rc = SQLITE_OK; 144 res.azResult = sqlite3_malloc(sizeof(char*)*res.nAlloc ); 145 if( res.azResult==0 ){ 146 db->errCode = SQLITE_NOMEM; 147 return SQLITE_NOMEM; 148 } 149 res.azResult[0] = 0; 150 rc = sqlite3_exec(db, zSql, sqlite3_get_table_cb, &res, pzErrMsg); 151 if( res.azResult ){ 152 assert( sizeof(res.azResult[0])>= sizeof(res.nData) ); 153 res.azResult[0] = (char*)res.nData; 154 } 155 if( (rc&0xff)==SQLITE_ABORT ){ 156 sqlite3_free_table(&res.azResult[1]); 157 if( res.zErrMsg ){ 158 if( pzErrMsg ){ 159 sqlite3_free(*pzErrMsg); 160 *pzErrMsg = sqlite3_mprintf("%s",res.zErrMsg); 161 } 162 sqlite3_free(res.zErrMsg); 163 } 164 db->errCode = res.rc; /* Assume 32-bit assignment is atomic */ 165 return res.rc; 166 } 167 sqlite3_free(res.zErrMsg); 168 if( rc!=SQLITE_OK ){ 169 sqlite3_free_table(&res.azResult[1]); 170 return rc; 171 } 172 if( res.nAlloc>res.nData ){ 173 char **azNew; 174 azNew = sqlite3_realloc( res.azResult, sizeof(char*)*(res.nData+1) ); 175 if( azNew==0 ){ 176 sqlite3_free_table(&res.azResult[1]); 177 db->errCode = SQLITE_NOMEM; 178 return SQLITE_NOMEM; 179 } 180 res.nAlloc = res.nData+1; 181 res.azResult = azNew; 182 } 183 *pazResult = &res.azResult[1]; 184 if( pnColumn ) *pnColumn = res.nColumn; 185 if( pnRow ) *pnRow = res.nRow; 186 return rc; 187 } 188 189 /* 190 ** This routine frees the space the sqlite3_get_table() malloced. 191 */ 192 void sqlite3_free_table( 193 char **azResult /* Result returned from from sqlite3_get_table() */ 194 ){ 195 if( azResult ){ 196 int i, n; 197 azResult--; 198 if( azResult==0 ) return; 199 n = (int)azResult[0]; 200 for(i=1; i<n; i++){ if( azResult[i] ) sqlite3_free(azResult[i]); } 201 sqlite3_free(azResult); 202 } 203 } 204 205 #endif /* SQLITE_OMIT_GET_TABLE */ 206