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*/
29typedef 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*/
44static 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
103malloc_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*/
118int 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*/
184void 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