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 ** $Id: table.c,v 1.40 2009/04/10 14:28:00 drh Exp $ 20 */ 21 #include "sqliteInt.h" 22 #include <stdlib.h> 23 #include <string.h> 24 25 #ifndef SQLITE_OMIT_GET_TABLE 26 27 /* 28 ** This structure is used to pass data from sqlite3_get_table() through 29 ** to the callback function is uses to build the result. 30 */ 31 typedef struct TabResult { 32 char **azResult; /* Accumulated output */ 33 char *zErrMsg; /* Error message text, if an error occurs */ 34 int nAlloc; /* Slots allocated for azResult[] */ 35 int nRow; /* Number of rows in the result */ 36 int nColumn; /* Number of columns in the result */ 37 int nData; /* Slots used in azResult[]. (nRow+1)*nColumn */ 38 int rc; /* Return code from sqlite3_exec() */ 39 } TabResult; 40 41 /* 42 ** This routine is called once for each row in the result table. Its job 43 ** is to fill in the TabResult structure appropriately, allocating new 44 ** memory as necessary. 45 */ 46 static int sqlite3_get_table_cb(void *pArg, int nCol, char **argv, char **colv){ 47 TabResult *p = (TabResult*)pArg; /* Result accumulator */ 48 int need; /* Slots needed in p->azResult[] */ 49 int i; /* Loop counter */ 50 char *z; /* A single column of result */ 51 52 /* Make sure there is enough space in p->azResult to hold everything 53 ** we need to remember from this invocation of the callback. 54 */ 55 if( p->nRow==0 && argv!=0 ){ 56 need = nCol*2; 57 }else{ 58 need = nCol; 59 } 60 if( p->nData + need > p->nAlloc ){ 61 char **azNew; 62 p->nAlloc = p->nAlloc*2 + need; 63 azNew = sqlite3_realloc( p->azResult, sizeof(char*)*p->nAlloc ); 64 if( azNew==0 ) goto malloc_failed; 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 z = sqlite3_mprintf("%s", colv[i]); 75 if( z==0 ) goto malloc_failed; 76 p->azResult[p->nData++] = z; 77 } 78 }else if( p->nColumn!=nCol ){ 79 sqlite3_free(p->zErrMsg); 80 p->zErrMsg = sqlite3_mprintf( 81 "sqlite3_get_table() called with two or more incompatible queries" 82 ); 83 p->rc = SQLITE_ERROR; 84 return 1; 85 } 86 87 /* Copy over the row data 88 */ 89 if( argv!=0 ){ 90 for(i=0; i<nCol; i++){ 91 if( argv[i]==0 ){ 92 z = 0; 93 }else{ 94 int n = sqlite3Strlen30(argv[i])+1; 95 z = sqlite3_malloc( n ); 96 if( z==0 ) goto malloc_failed; 97 memcpy(z, argv[i], n); 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; 130 131 *pazResult = 0; 132 if( pnColumn ) *pnColumn = 0; 133 if( pnRow ) *pnRow = 0; 134 if( pzErrMsg ) *pzErrMsg = 0; 135 res.zErrMsg = 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 ){ 143 db->errCode = SQLITE_NOMEM; 144 return SQLITE_NOMEM; 145 } 146 res.azResult[0] = 0; 147 rc = sqlite3_exec(db, zSql, sqlite3_get_table_cb, &res, pzErrMsg); 148 assert( sizeof(res.azResult[0])>= sizeof(res.nData) ); 149 res.azResult[0] = SQLITE_INT_TO_PTR(res.nData); 150 if( (rc&0xff)==SQLITE_ABORT ){ 151 sqlite3_free_table(&res.azResult[1]); 152 if( res.zErrMsg ){ 153 if( pzErrMsg ){ 154 sqlite3_free(*pzErrMsg); 155 *pzErrMsg = sqlite3_mprintf("%s",res.zErrMsg); 156 } 157 sqlite3_free(res.zErrMsg); 158 } 159 db->errCode = res.rc; /* Assume 32-bit assignment is atomic */ 160 return res.rc; 161 } 162 sqlite3_free(res.zErrMsg); 163 if( rc!=SQLITE_OK ){ 164 sqlite3_free_table(&res.azResult[1]); 165 return rc; 166 } 167 if( res.nAlloc>res.nData ){ 168 char **azNew; 169 azNew = sqlite3_realloc( res.azResult, sizeof(char*)*res.nData ); 170 if( azNew==0 ){ 171 sqlite3_free_table(&res.azResult[1]); 172 db->errCode = SQLITE_NOMEM; 173 return SQLITE_NOMEM; 174 } 175 res.azResult = azNew; 176 } 177 *pazResult = &res.azResult[1]; 178 if( pnColumn ) *pnColumn = res.nColumn; 179 if( pnRow ) *pnRow = res.nRow; 180 return rc; 181 } 182 183 /* 184 ** This routine frees the space the sqlite3_get_table() malloced. 185 */ 186 void sqlite3_free_table( 187 char **azResult /* Result returned from from sqlite3_get_table() */ 188 ){ 189 if( azResult ){ 190 int i, n; 191 azResult--; 192 assert( azResult!=0 ); 193 n = SQLITE_PTR_TO_INT(azResult[0]); 194 for(i=1; i<n; i++){ if( azResult[i] ) sqlite3_free(azResult[i]); } 195 sqlite3_free(azResult); 196 } 197 } 198 199 #endif /* SQLITE_OMIT_GET_TABLE */ 200