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Overview
Comment: | Improve the readability of the unionvtab code. |
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Downloads: | Tarball | ZIP archive |
Timelines: | family | ancestors | descendants | both | trunk |
Files: | files | file ages | folders |
SHA3-256: |
5bcf0f86ea7fbbc31a13b2d5b1cf93a9 |
User & Date: | dan 2017-07-18 20:03:49.037 |
Context
2017-07-18
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20:17 | Remove an unused variable from unionvtab.c. (check-in: a447fdf182 user: dan tags: trunk) | |
20:03 | Improve the readability of the unionvtab code. (check-in: 5bcf0f86ea user: dan tags: trunk) | |
19:51 | Have unionvtab support constraints on the column that corresponds to the INTEGER PRIMARY KEY field of the underlying source tables in the same way as rowid. (check-in: 4a6c416fa0 user: dan tags: trunk) | |
Changes
Changes to ext/misc/unionvtab.c.
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148 149 150 151 152 153 154 | ** in SQL, this function assumes that the input is a well-formed quoted SQL ** string. In this case the string is dequoted in place. ** ** If the first character of the input is not an open quote, then this ** function is a no-op. */ static void unionDequote(char *z){ | > | | | | | | | | | | | | | | | | | | | | | | | | > | 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 | ** in SQL, this function assumes that the input is a well-formed quoted SQL ** string. In this case the string is dequoted in place. ** ** If the first character of the input is not an open quote, then this ** function is a no-op. */ static void unionDequote(char *z){ if( z ){ char q = z[0]; /* Set stack variable q to the close-quote character */ if( q=='[' || q=='\'' || q=='"' || q=='`' ){ int iIn = 1; int iOut = 0; if( q=='[' ) q = ']'; while( z[iIn] ){ if( z[iIn]==q ){ if( z[iIn+1]!=q ){ /* Character iIn was the close quote. */ iIn++; break; }else{ /* Character iIn and iIn+1 form an escaped quote character. Skip ** the input cursor past both and copy a single quote character ** to the output buffer. */ iIn += 2; z[iOut++] = q; } }else{ z[iOut++] = z[iIn++]; } } z[iOut] = '\0'; } } } /* ** This function is a no-op if *pRc is set to other than SQLITE_OK when it ** is called. NULL is returned in this case. ** |
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205 206 207 208 209 210 211 212 213 214 215 216 217 218 | if( rc!=SQLITE_OK ){ *pzErr = sqlite3_mprintf("sql error: %s", sqlite3_errmsg(db)); *pRc = rc; } } return pRet; } /* ** Call sqlite3_reset() on SQL statement pStmt. If *pRc is set to ** SQLITE_OK when this function is called, then it is set to the ** value returned by sqlite3_reset() before this function exits. ** In this case, *pzErr may be set to point to an error message ** buffer allocated by sqlite3_malloc(). | > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > | 207 208 209 210 211 212 213 214 215 216 217 218 219 220 221 222 223 224 225 226 227 228 229 230 231 232 233 234 235 236 237 238 239 240 241 242 243 244 245 246 247 248 249 250 251 | if( rc!=SQLITE_OK ){ *pzErr = sqlite3_mprintf("sql error: %s", sqlite3_errmsg(db)); *pRc = rc; } } return pRet; } /* ** Like unionPrepare(), except prepare the results of vprintf(zFmt, ...) ** instead of a constant SQL string. */ static sqlite3_stmt *unionPreparePrintf( int *pRc, /* IN/OUT: Error code */ char **pzErr, /* OUT: Error message */ sqlite3 *db, /* Database handle */ const char *zFmt, /* printf() format string */ ... /* Trailing printf args */ ){ sqlite3_stmt *pRet = 0; char *zSql; va_list ap; va_start(ap, zFmt); zSql = sqlite3_vmprintf(zFmt, ap); if( *pRc==SQLITE_OK ){ if( zSql==0 ){ *pRc = SQLITE_NOMEM; }else{ pRet = unionPrepare(pRc, db, zSql, pzErr); } } sqlite3_free(zSql); va_end(ap); return pRet; } /* ** Call sqlite3_reset() on SQL statement pStmt. If *pRc is set to ** SQLITE_OK when this function is called, then it is set to the ** value returned by sqlite3_reset() before this function exits. ** In this case, *pzErr may be set to point to an error message ** buffer allocated by sqlite3_malloc(). |
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386 387 388 389 390 391 392 | char *zSql = 0; /* SQL statement */ char *zArg = unionStrdup(&rc, argv[3]); /* Copy of argument to CVT */ /* Prepare the SQL statement. Instead of executing it directly, sort ** the results by the "minimum rowid" field. This makes it easier to ** check that there are no rowid range overlaps between source tables ** and that the UnionTab.aSrc[] array is always sorted by rowid. */ | < | > | | < < < < < < | 419 420 421 422 423 424 425 426 427 428 429 430 431 432 433 434 435 436 | char *zSql = 0; /* SQL statement */ char *zArg = unionStrdup(&rc, argv[3]); /* Copy of argument to CVT */ /* Prepare the SQL statement. Instead of executing it directly, sort ** the results by the "minimum rowid" field. This makes it easier to ** check that there are no rowid range overlaps between source tables ** and that the UnionTab.aSrc[] array is always sorted by rowid. */ unionDequote(zArg); pStmt = unionPreparePrintf(&rc, pzErr, db, "SELECT * FROM (%z) ORDER BY 3", zArg ); /* Allocate the UnionTab structure */ pTab = unionMalloc(&rc, sizeof(UnionTab)); /* Iterate through the rows returned by the SQL statement specified ** as an argument to the CREATE VIRTUAL TABLE statement. */ while( rc==SQLITE_OK && SQLITE_ROW==sqlite3_step(pStmt) ){ |
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439 440 441 442 443 444 445 | pSrc->zDb = unionStrdup(&rc, zDb); pSrc->zTab = unionStrdup(&rc, zTab); pSrc->iMin = iMin; pSrc->iMax = iMax; } unionFinalize(&rc, pStmt); pStmt = 0; | < < < | | | | | | | | < < < | 466 467 468 469 470 471 472 473 474 475 476 477 478 479 480 481 482 483 484 485 486 487 488 489 490 491 492 493 494 495 496 497 | pSrc->zDb = unionStrdup(&rc, zDb); pSrc->zTab = unionStrdup(&rc, zTab); pSrc->iMin = iMin; pSrc->iMax = iMax; } unionFinalize(&rc, pStmt); pStmt = 0; sqlite3_free(zSql); zSql = 0; /* Verify that all source tables exist and have compatible schemas. */ if( rc==SQLITE_OK ){ pTab->db = db; rc = unionSourceCheck(pTab, pzErr); } /* Compose a CREATE TABLE statement and pass it to declare_vtab() */ pStmt = unionPreparePrintf(&rc, pzErr, db, "SELECT " "'CREATE TABLE xyz('" " || group_concat(quote(name) || ' ' || type, ', ')" " || ')'," "max((cid+1) * (type='INTEGER' COLLATE nocase AND pk=1))-1 " "FROM pragma_table_info(%Q, ?)", pTab->aSrc[0].zTab, pTab->aSrc[0].zDb ); if( rc==SQLITE_OK && SQLITE_ROW==sqlite3_step(pStmt) ){ const char *zDecl = (const char*)sqlite3_column_text(pStmt, 0); rc = sqlite3_declare_vtab(db, zDecl); pTab->iPK = sqlite3_column_int(pStmt, 1); } unionFinalize(&rc, pStmt); |
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