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; /* Accumulated output */ 31 char *zErrMsg; /* Error message text, if an error occurs */ 32 int nAlloc; /* Slots allocated for azResult[] */ 33 int nRow; /* Number of rows in the result */ 34 int nColumn; /* Number of columns in the result */ 35 int nData; /* Slots used in azResult[]. (nRow+1)*nColumn */ 36 int rc; /* Return code from sqlite3_exec() */ 37 } TabResult; 38 39 /* 40 ** This routine is called once for each row in the result table. Its job 41 ** is to fill in the TabResult structure appropriately, allocating new 42 ** memory as necessary. 43 */ 44 static int sqlite3_get_table_cb(void *pArg, int nCol, char **argv, char **colv){ 45 TabResult *p = (TabResult*)pArg; /* Result accumulator */ 46 int need; /* Slots needed in p->azResult[] */ 47 int i; /* Loop counter */ 48 char *z; /* A single column of result */ 49 50 /* Make sure there is enough space in p->azResult to hold everything 51 ** we need to remember from this invocation of the callback. 52 */ 53 if( p->nRow==0 && argv!=0 ){ 54 need = nCol*2; 55 }else{ 56 need = nCol; 57 } 58 if( p->nData + need > p->nAlloc ){ 59 char **azNew; 60 p->nAlloc = p->nAlloc*2 + need; 61 azNew = sqlite3_realloc( p->azResult, sizeof(char*)*p->nAlloc ); 62 if( azNew==0 ) goto malloc_failed; 63 p->azResult = azNew; 64 } 65 66 /* If this is the first row, then generate an extra row containing 67 ** the names of all columns. 68 */ 69 if( p->nRow==0 ){ 70 p->nColumn = nCol; 71 for(i=0; i<nCol; i++){ 72 z = sqlite3_mprintf("%s", colv[i]); 73 if( z==0 ) goto malloc_failed; 74 p->azResult[p->nData++] = z; 75 } 76 }else if( p->nColumn!=nCol ){ 77 sqlite3_free(p->zErrMsg); 78 p->zErrMsg = sqlite3_mprintf( 79 "sqlite3_get_table() called with two or more incompatible queries" 80 ); 81 p->rc = SQLITE_ERROR; 82 return 1; 83 } 84 85 /* Copy over the row data 86 */ 87 if( argv!=0 ){ 88 for(i=0; i<nCol; i++){ 89 if( argv[i]==0 ){ 90 z = 0; 91 }else{ 92 int n = sqlite3Strlen30(argv[i])+1; 93 z = sqlite3_malloc( n ); 94 if( z==0 ) goto malloc_failed; 95 memcpy(z, argv[i], n); 96 } 97 p->azResult[p->nData++] = z; 98 } 99 p->nRow++; 100 } 101 return 0; 102 103 malloc_failed: 104 p->rc = SQLITE_NOMEM; 105 return 1; 106 } 107 108 /* 109 ** Query the database. But instead of invoking a callback for each row, 110 ** malloc() for space to hold the result and return the entire results 111 ** at the conclusion of the call. 112 ** 113 ** The result that is written to ***pazResult is held in memory obtained 114 ** from malloc(). But the caller cannot free this memory directly. 115 ** Instead, the entire table should be passed to sqlite3_free_table() when 116 ** the calling procedure is finished using it. 117 */ 118 int sqlite3_get_table( 119 sqlite3 *db, /* The database on which the SQL executes */ 120 const char *zSql, /* The SQL to be executed */ 121 char ***pazResult, /* Write the result table here */ 122 int *pnRow, /* Write the number of rows in the result here */ 123 int *pnColumn, /* Write the number of columns of result here */ 124 char **pzErrMsg /* Write error messages here */ 125 ){ 126 int rc; 127 TabResult res; 128 129 *pazResult = 0; 130 if( pnColumn ) *pnColumn = 0; 131 if( pnRow ) *pnRow = 0; 132 if( pzErrMsg ) *pzErrMsg = 0; 133 res.zErrMsg = 0; 134 res.nRow = 0; 135 res.nColumn = 0; 136 res.nData = 1; 137 res.nAlloc = 20; 138 res.rc = SQLITE_OK; 139 res.azResult = sqlite3_malloc(sizeof(char*)*res.nAlloc ); 140 if( res.azResult==0 ){ 141 db->errCode = SQLITE_NOMEM; 142 return SQLITE_NOMEM; 143 } 144 res.azResult[0] = 0; 145 rc = sqlite3_exec(db, zSql, sqlite3_get_table_cb, &res, pzErrMsg); 146 assert( sizeof(res.azResult[0])>= sizeof(res.nData) ); 147 res.azResult[0] = SQLITE_INT_TO_PTR(res.nData); 148 if( (rc&0xff)==SQLITE_ABORT ){ 149 sqlite3_free_table(&res.azResult[1]); 150 if( res.zErrMsg ){ 151 if( pzErrMsg ){ 152 sqlite3_free(*pzErrMsg); 153 *pzErrMsg = sqlite3_mprintf("%s",res.zErrMsg); 154 } 155 sqlite3_free(res.zErrMsg); 156 } 157 db->errCode = res.rc; /* Assume 32-bit assignment is atomic */ 158 return res.rc; 159 } 160 sqlite3_free(res.zErrMsg); 161 if( rc!=SQLITE_OK ){ 162 sqlite3_free_table(&res.azResult[1]); 163 return rc; 164 } 165 if( res.nAlloc>res.nData ){ 166 char **azNew; 167 azNew = sqlite3_realloc( res.azResult, sizeof(char*)*res.nData ); 168 if( azNew==0 ){ 169 sqlite3_free_table(&res.azResult[1]); 170 db->errCode = SQLITE_NOMEM; 171 return SQLITE_NOMEM; 172 } 173 res.azResult = azNew; 174 } 175 *pazResult = &res.azResult[1]; 176 if( pnColumn ) *pnColumn = res.nColumn; 177 if( pnRow ) *pnRow = res.nRow; 178 return rc; 179 } 180 181 /* 182 ** This routine frees the space the sqlite3_get_table() malloced. 183 */ 184 void sqlite3_free_table( 185 char **azResult /* Result returned from from sqlite3_get_table() */ 186 ){ 187 if( azResult ){ 188 int i, n; 189 azResult--; 190 assert( azResult!=0 ); 191 n = SQLITE_PTR_TO_INT(azResult[0]); 192 for(i=1; i<n; i++){ if( azResult[i] ) sqlite3_free(azResult[i]); } 193 sqlite3_free(azResult); 194 } 195 } 196 197 #endif /* SQLITE_OMIT_GET_TABLE */ 198
