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1 /* |
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2 ** 2001 September 15 |
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3 ** |
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4 ** The author disclaims copyright to this source code. In place of |
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5 ** a legal notice, here is a blessing: |
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6 ** |
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7 ** May you do good and not evil. |
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8 ** May you find forgiveness for yourself and forgive others. |
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9 ** May you share freely, never taking more than you give. |
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10 ** |
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11 ************************************************************************* |
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12 ** This file contains the sqlite3_get_table() and sqlite3_free_table() |
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13 ** interface routines. These are just wrappers around the main |
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14 ** interface routine of sqlite3_exec(). |
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15 ** |
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16 ** These routines are in a separate files so that they will not be linked |
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17 ** if they are not used. |
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18 */ |
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19 #include "sqliteInt.h" |
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20 #include <stdlib.h> |
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21 #include <string.h> |
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22 |
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23 #ifndef SQLITE_OMIT_GET_TABLE |
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24 |
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25 /* |
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26 ** This structure is used to pass data from sqlite3_get_table() through |
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27 ** to the callback function is uses to build the result. |
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28 */ |
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29 typedef struct TabResult { |
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30 char **azResult; |
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31 char *zErrMsg; |
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32 int nResult; |
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33 int nAlloc; |
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34 int nRow; |
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35 int nColumn; |
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36 int nData; |
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37 int rc; |
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38 } TabResult; |
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39 |
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40 /* |
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41 ** This routine is called once for each row in the result table. Its job |
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42 ** is to fill in the TabResult structure appropriately, allocating new |
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43 ** memory as necessary. |
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44 */ |
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45 static int sqlite3_get_table_cb(void *pArg, int nCol, char **argv, char **colv){ |
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46 TabResult *p = (TabResult*)pArg; |
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47 int need; |
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48 int i; |
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49 char *z; |
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50 |
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51 /* Make sure there is enough space in p->azResult to hold everything |
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52 ** we need to remember from this invocation of the callback. |
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53 */ |
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54 if( p->nRow==0 && argv!=0 ){ |
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55 need = nCol*2; |
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56 }else{ |
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57 need = nCol; |
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58 } |
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59 if( p->nData + need >= p->nAlloc ){ |
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60 char **azNew; |
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61 p->nAlloc = p->nAlloc*2 + need + 1; |
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62 azNew = sqlite3_realloc( p->azResult, sizeof(char*)*p->nAlloc ); |
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63 if( azNew==0 ) goto malloc_failed; |
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64 p->azResult = azNew; |
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65 } |
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66 |
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67 /* If this is the first row, then generate an extra row containing |
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68 ** the names of all columns. |
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69 */ |
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70 if( p->nRow==0 ){ |
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71 p->nColumn = nCol; |
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72 for(i=0; i<nCol; i++){ |
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73 if( colv[i]==0 ){ |
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74 z = sqlite3_mprintf(""); |
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75 }else{ |
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76 z = sqlite3_mprintf("%s", colv[i]); |
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77 } |
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78 p->azResult[p->nData++] = z; |
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79 } |
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80 }else if( p->nColumn!=nCol ){ |
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81 sqlite3SetString(&p->zErrMsg, |
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82 "sqlite3_get_table() called with two or more incompatible queries", |
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83 (char*)0); |
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84 p->rc = SQLITE_ERROR; |
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85 return 1; |
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86 } |
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87 |
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88 /* Copy over the row data |
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89 */ |
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90 if( argv!=0 ){ |
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91 for(i=0; i<nCol; i++){ |
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92 if( argv[i]==0 ){ |
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93 z = 0; |
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94 }else{ |
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95 z = sqlite3_malloc( strlen(argv[i])+1 ); |
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96 if( z==0 ) goto malloc_failed; |
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97 strcpy(z, argv[i]); |
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98 } |
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99 p->azResult[p->nData++] = z; |
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100 } |
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101 p->nRow++; |
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102 } |
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103 return 0; |
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104 |
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105 malloc_failed: |
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106 p->rc = SQLITE_NOMEM; |
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107 return 1; |
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108 } |
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109 |
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110 /* |
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111 ** Query the database. But instead of invoking a callback for each row, |
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112 ** malloc() for space to hold the result and return the entire results |
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113 ** at the conclusion of the call. |
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114 ** |
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115 ** The result that is written to ***pazResult is held in memory obtained |
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116 ** from malloc(). But the caller cannot free this memory directly. |
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117 ** Instead, the entire table should be passed to sqlite3_free_table() when |
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118 ** the calling procedure is finished using it. |
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119 */ |
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120 int sqlite3_get_table( |
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121 sqlite3 *db, /* The database on which the SQL executes */ |
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122 const char *zSql, /* The SQL to be executed */ |
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123 char ***pazResult, /* Write the result table here */ |
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124 int *pnRow, /* Write the number of rows in the result here */ |
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125 int *pnColumn, /* Write the number of columns of result here */ |
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126 char **pzErrMsg /* Write error messages here */ |
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127 ){ |
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128 int rc; |
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129 TabResult res; |
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130 if( pazResult==0 ){ return SQLITE_ERROR; } |
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131 *pazResult = 0; |
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132 if( pnColumn ) *pnColumn = 0; |
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133 if( pnRow ) *pnRow = 0; |
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134 res.zErrMsg = 0; |
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135 res.nResult = 0; |
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136 res.nRow = 0; |
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137 res.nColumn = 0; |
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138 res.nData = 1; |
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139 res.nAlloc = 20; |
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140 res.rc = SQLITE_OK; |
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141 res.azResult = sqlite3_malloc( sizeof(char*)*res.nAlloc ); |
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142 if( res.azResult==0 ) return SQLITE_NOMEM; |
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143 res.azResult[0] = 0; |
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144 rc = sqlite3_exec(db, zSql, sqlite3_get_table_cb, &res, pzErrMsg); |
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145 if( res.azResult ){ |
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146 assert( sizeof(res.azResult[0])>= sizeof(res.nData) ); |
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147 res.azResult[0] = (char*)res.nData; |
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148 } |
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149 if( rc==SQLITE_ABORT ){ |
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150 sqlite3_free_table(&res.azResult[1]); |
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151 if( res.zErrMsg ){ |
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152 if( pzErrMsg ){ |
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153 sqlite3_free(*pzErrMsg); |
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154 *pzErrMsg = sqlite3_mprintf("%s",res.zErrMsg); |
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155 } |
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156 sqliteFree(res.zErrMsg); |
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157 } |
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158 db->errCode = res.rc; |
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159 return res.rc; |
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160 } |
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161 sqliteFree(res.zErrMsg); |
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162 if( rc!=SQLITE_OK ){ |
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163 sqlite3_free_table(&res.azResult[1]); |
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164 return rc; |
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165 } |
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166 if( res.nAlloc>res.nData ){ |
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167 char **azNew; |
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168 azNew = sqlite3_realloc( res.azResult, sizeof(char*)*(res.nData+1) ); |
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169 if( azNew==0 ){ |
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170 sqlite3_free_table(&res.azResult[1]); |
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171 return SQLITE_NOMEM; |
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172 } |
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173 res.nAlloc = res.nData+1; |
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174 res.azResult = azNew; |
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175 } |
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176 *pazResult = &res.azResult[1]; |
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177 if( pnColumn ) *pnColumn = res.nColumn; |
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178 if( pnRow ) *pnRow = res.nRow; |
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179 return rc; |
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180 } |
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181 |
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182 /* |
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183 ** This routine frees the space the sqlite3_get_table() malloced. |
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184 */ |
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185 void sqlite3_free_table( |
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186 char **azResult /* Result returned from from sqlite3_get_table() */ |
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187 ){ |
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188 if( azResult ){ |
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189 int i, n; |
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190 azResult--; |
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191 if( azResult==0 ) return; |
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192 n = (int)azResult[0]; |
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193 for(i=1; i<n; i++){ if( azResult[i] ) sqlite3_free(azResult[i]); } |
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194 sqlite3_free(azResult); |
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195 } |
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196 } |
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197 |
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198 #endif /* SQLITE_OMIT_GET_TABLE */ |