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 sqlite_get_table() and sqlite_free_table() 13 ** interface routines. These are just wrappers around the main 14 ** interface routine of sqlite_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 <stdlib.h> 20 #include <string.h> 21 #include "sqliteInt.h" 22 23 /* 24 ** This structure is used to pass data from sqlite_get_table() through 25 ** to the callback function is uses to build the result. 26 */ 27 typedef struct TabResult { 28 char **azResult; 29 char *zErrMsg; 30 int nResult; 31 int nAlloc; 32 int nRow; 33 int nColumn; 34 int nData; 35 int rc; 36 } TabResult; 37 38 /* 39 ** This routine is called once for each row in the result table. Its job 40 ** is to fill in the TabResult structure appropriately, allocating new 41 ** memory as necessary. 42 */ 43 static int sqlite_get_table_cb(void *pArg, int nCol, char **argv, char **colv){ 44 TabResult *p = (TabResult*)pArg; 45 int need; 46 int i; 47 char *z; 48 49 /* Make sure there is enough space in p->azResult to hold everything 50 ** we need to remember from this invocation of the callback. 51 */ 52 if( p->nRow==0 && argv!=0 ){ 53 need = nCol*2; 54 }else{ 55 need = nCol; 56 } 57 if( p->nData + need >= p->nAlloc ){ 58 char **azNew; 59 p->nAlloc = p->nAlloc*2 + need + 1; 60 azNew = realloc( p->azResult, sizeof(char*)*p->nAlloc ); 61 if( azNew==0 ){ 62 p->rc = SQLITE_NOMEM; 63 return 1; 64 } 65 p->azResult = azNew; 66 } 67 68 /* If this is the first row, then generate an extra row containing 69 ** the names of all columns. 70 */ 71 if( p->nRow==0 ){ 72 p->nColumn = nCol; 73 for(i=0; i<nCol; i++){ 74 if( colv[i]==0 ){ 75 z = 0; 76 }else{ 77 z = malloc( strlen(colv[i])+1 ); 78 if( z==0 ){ 79 p->rc = SQLITE_NOMEM; 80 return 1; 81 } 82 strcpy(z, colv[i]); 83 } 84 p->azResult[p->nData++] = z; 85 } 86 }else if( p->nColumn!=nCol ){ 87 sqliteSetString(&p->zErrMsg, 88 "sqlite_get_table() called with two or more incompatible queries", 0); 89 p->rc = SQLITE_ERROR; 90 return 1; 91 } 92 93 /* Copy over the row data 94 */ 95 if( argv!=0 ){ 96 for(i=0; i<nCol; i++){ 97 if( argv[i]==0 ){ 98 z = 0; 99 }else{ 100 z = malloc( strlen(argv[i])+1 ); 101 if( z==0 ){ 102 p->rc = SQLITE_NOMEM; 103 return 1; 104 } 105 strcpy(z, argv[i]); 106 } 107 p->azResult[p->nData++] = z; 108 } 109 p->nRow++; 110 } 111 return 0; 112 } 113 114 /* 115 ** Query the database. But instead of invoking a callback for each row, 116 ** malloc() for space to hold the result and return the entire results 117 ** at the conclusion of the call. 118 ** 119 ** The result that is written to ***pazResult is held in memory obtained 120 ** from malloc(). But the caller cannot free this memory directly. 121 ** Instead, the entire table should be passed to sqlite_free_table() when 122 ** the calling procedure is finished using it. 123 */ 124 int sqlite_get_table( 125 sqlite *db, /* The database on which the SQL executes */ 126 const char *zSql, /* The SQL to be executed */ 127 char ***pazResult, /* Write the result table here */ 128 int *pnRow, /* Write the number of rows in the result here */ 129 int *pnColumn, /* Write the number of columns of result here */ 130 char **pzErrMsg /* Write error messages here */ 131 ){ 132 int rc; 133 TabResult res; 134 if( pazResult==0 ){ return SQLITE_ERROR; } 135 *pazResult = 0; 136 if( pnColumn ) *pnColumn = 0; 137 if( pnRow ) *pnRow = 0; 138 res.zErrMsg = 0; 139 res.nResult = 0; 140 res.nRow = 0; 141 res.nColumn = 0; 142 res.nData = 1; 143 res.nAlloc = 20; 144 res.rc = SQLITE_OK; 145 res.azResult = malloc( sizeof(char*)*res.nAlloc ); 146 if( res.azResult==0 ){ 147 return SQLITE_NOMEM; 148 } 149 res.azResult[0] = 0; 150 rc = sqlite_exec(db, zSql, sqlite_get_table_cb, &res, pzErrMsg); 151 if( res.azResult ){ 152 res.azResult[0] = (char*)res.nData; 153 } 154 if( rc==SQLITE_ABORT ){ 155 sqlite_free_table(&res.azResult[1]); 156 if( res.zErrMsg ){ 157 if( pzErrMsg ){ 158 free(*pzErrMsg); 159 *pzErrMsg = res.zErrMsg; 160 sqliteStrRealloc(pzErrMsg); 161 }else{ 162 sqliteFree(res.zErrMsg); 163 } 164 } 165 return res.rc; 166 } 167 sqliteFree(res.zErrMsg); 168 if( rc!=SQLITE_OK ){ 169 sqlite_free_table(&res.azResult[1]); 170 return rc; 171 } 172 if( res.nAlloc>res.nData ){ 173 char **azNew; 174 azNew = realloc( res.azResult, sizeof(char*)*(res.nData+1) ); 175 if( azNew==0 ){ 176 sqlite_free_table(&res.azResult[1]); 177 return SQLITE_NOMEM; 178 } 179 res.nAlloc = res.nData+1; 180 res.azResult = azNew; 181 } 182 *pazResult = &res.azResult[1]; 183 if( pnColumn ) *pnColumn = res.nColumn; 184 if( pnRow ) *pnRow = res.nRow; 185 return rc; 186 } 187 188 /* 189 ** This routine frees the space the sqlite_get_table() malloced. 190 */ 191 void sqlite_free_table( 192 char **azResult /* Result returned from from sqlite_get_table() */ 193 ){ 194 if( azResult ){ 195 int i, n; 196 azResult--; 197 if( azResult==0 ) return; 198 n = (int)azResult[0]; 199 for(i=1; i<n; i++){ if( azResult[i] ) free(azResult[i]); } 200 free(azResult); 201 } 202 } 203