AryaWu/sqlite
0
1/*2** 2001 September 153**4** The author disclaims copyright to this source code. In place of5** 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 main14** interface routine of sqlite3_exec().15**16** These routines are in a separate files so that they will not be linked17** if they are not used.18*/19#include "sqliteInt.h"20 21#ifndef SQLITE_OMIT_GET_TABLE22 23/*24** This structure is used to pass data from sqlite3_get_table() through25** to the callback function is uses to build the result.26*/27typedef 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 job39** is to fill in the TabResult structure appropriately, allocating new40** memory as necessary.41*/42static 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 everything49 ** 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 containing65 ** 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 data84 */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 101malloc_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 results109** at the conclusion of the call.110**111** The result that is written to ***pazResult is held in memory obtained112** from malloc(). But the caller cannot free this memory directly. 113** Instead, the entire table should be passed to sqlite3_free_table() when114** the calling procedure is finished using it.115*/116int 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_ARMOR128 if( !sqlite3SafetyCheckOk(db) || pazResult==0 ) return SQLITE_MISUSE_BKPT;129#endif130 *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*/185void 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