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|    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 */ |  | 
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