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Overview
Comment: | Cache the JSON parse used by json_extract(). |
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Downloads: | Tarball | ZIP archive |
Timelines: | family | ancestors | descendants | both | auxdata-cache |
Files: | files | file ages | folders |
SHA3-256: |
44ca6c2c4639f3c50ae9233ee299ff0f |
User & Date: | drh 2017-05-11 16:49:59.245 |
Context
2017-05-11
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18:42 | Enhance the json_extract() function to reuse parses of the same JSON when the function appears multiple times in the same query. (check-in: 3ba9e7ab79 user: drh tags: trunk) | |
16:49 | Cache the JSON parse used by json_extract(). (Closed-Leaf check-in: 44ca6c2c46 user: drh tags: auxdata-cache) | |
15:20 | Negative N values in sqlite3_get_auxdata() and sqlite3_set_auxdata() can be used to access an auxiliary data cache over all functions in a single prepared statement. (check-in: ff5306752e user: drh tags: auxdata-cache) | |
Changes
Changes to ext/misc/json1.c.
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167 168 169 170 171 172 173 174 175 176 177 178 179 180 | u32 nAlloc; /* Number of slots of aNode[] allocated */ JsonNode *aNode; /* Array of nodes containing the parse */ const char *zJson; /* Original JSON string */ u32 *aUp; /* Index of parent of each node */ u8 oom; /* Set to true if out of memory */ u8 nErr; /* Number of errors seen */ u16 iDepth; /* Nesting depth */ }; /* ** Maximum nesting depth of JSON for this implementation. ** ** This limit is needed to avoid a stack overflow in the recursive ** descent parser. A depth of 2000 is far deeper than any sane JSON | > | 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 | u32 nAlloc; /* Number of slots of aNode[] allocated */ JsonNode *aNode; /* Array of nodes containing the parse */ const char *zJson; /* Original JSON string */ u32 *aUp; /* Index of parent of each node */ u8 oom; /* Set to true if out of memory */ u8 nErr; /* Number of errors seen */ u16 iDepth; /* Nesting depth */ int nJson; /* Length of the zJson string in bytes */ }; /* ** Maximum nesting depth of JSON for this implementation. ** ** This limit is needed to avoid a stack overflow in the recursive ** descent parser. A depth of 2000 is far deeper than any sane JSON |
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408 409 410 411 412 413 414 415 416 417 418 419 420 421 | sqlite3_free(pParse->aNode); pParse->aNode = 0; pParse->nNode = 0; pParse->nAlloc = 0; sqlite3_free(pParse->aUp); pParse->aUp = 0; } /* ** Convert the JsonNode pNode into a pure JSON string and ** append to pOut. Subsubstructure is also included. Return ** the number of JsonNode objects that are encoded. */ static void jsonRenderNode( | > > > > > > > > | 409 410 411 412 413 414 415 416 417 418 419 420 421 422 423 424 425 426 427 428 429 430 | sqlite3_free(pParse->aNode); pParse->aNode = 0; pParse->nNode = 0; pParse->nAlloc = 0; sqlite3_free(pParse->aUp); pParse->aUp = 0; } /* ** Free a JsonParse object that was obtained from sqlite3_malloc(). */ static void jsonParseFree(JsonParse *pParse){ jsonParseReset(pParse); sqlite3_free(pParse); } /* ** Convert the JsonNode pNode into a pure JSON string and ** append to pOut. Subsubstructure is also included. Return ** the number of JsonNode objects that are encoded. */ static void jsonRenderNode( |
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959 960 961 962 963 964 965 966 967 968 969 970 971 972 | if( aUp==0 ){ pParse->oom = 1; return SQLITE_NOMEM; } jsonParseFillInParentage(pParse, 0, 0); return SQLITE_OK; } /* ** Compare the OBJECT label at pNode against zKey,nKey. Return true on ** a match. */ static int jsonLabelCompare(JsonNode *pNode, const char *zKey, u32 nKey){ if( pNode->jnFlags & JNODE_RAW ){ | > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > | 968 969 970 971 972 973 974 975 976 977 978 979 980 981 982 983 984 985 986 987 988 989 990 991 992 993 994 995 996 997 998 999 1000 1001 1002 1003 1004 1005 1006 1007 1008 1009 1010 1011 1012 1013 1014 1015 1016 1017 1018 1019 1020 1021 1022 1023 1024 | if( aUp==0 ){ pParse->oom = 1; return SQLITE_NOMEM; } jsonParseFillInParentage(pParse, 0, 0); return SQLITE_OK; } /* ** Magic number used for the JSON parse cache in sqlite3_get_auxdata() */ #define JSON_CACHE_ID (-429938) /* ** Obtain a complete parse of the JSON found in the first argument ** of the argv array. Use the sqlite3_get_auxdata() cache for this ** parse if it is available. If the cache is not available or if it ** is no longer valid, parse the JSON again and return the new parse, ** and also register the new parse so that it will be available for ** future sqlite3_get_auxdata() calls. */ static JsonParse *jsonParseCached( sqlite3_context *pCtx, sqlite3_value **argv ){ const char *zJson = (const char*)sqlite3_value_text(argv[0]); int nJson = sqlite3_value_bytes(argv[0]); JsonParse *p; if( zJson==0 ) return 0; p = (JsonParse*)sqlite3_get_auxdata(pCtx, JSON_CACHE_ID); if( p && p->nJson==nJson && memcmp(p->zJson,zJson,nJson)==0 ){ p->nErr = 0; return p; /* The cached entry matches, so return it */ } p = sqlite3_malloc( sizeof(*p) + nJson + 1 ); if( p==0 ){ sqlite3_result_error_nomem(pCtx); return 0; } memset(p, 0, sizeof(*p)); p->zJson = (char*)&p[1]; memcpy((char*)p->zJson, zJson, nJson+1); if( jsonParse(p, pCtx, p->zJson) ){ sqlite3_free(p); return 0; } p->nJson = nJson; sqlite3_set_auxdata(pCtx, JSON_CACHE_ID, p, (void(*)(void*))jsonParseFree); return (JsonParse*)sqlite3_get_auxdata(pCtx, JSON_CACHE_ID); } /* ** Compare the OBJECT label at pNode against zKey,nKey. Return true on ** a match. */ static int jsonLabelCompare(JsonNode *pNode, const char *zKey, u32 nKey){ if( pNode->jnFlags & JNODE_RAW ){ |
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1325 1326 1327 1328 1329 1330 1331 | ** Return 0 if the input is not a well-formed JSON array. */ static void jsonArrayLengthFunc( sqlite3_context *ctx, int argc, sqlite3_value **argv ){ | | | > | | | | > | | < | | > | | < | 1377 1378 1379 1380 1381 1382 1383 1384 1385 1386 1387 1388 1389 1390 1391 1392 1393 1394 1395 1396 1397 1398 1399 1400 1401 1402 1403 1404 1405 1406 1407 1408 1409 1410 1411 1412 1413 1414 1415 1416 1417 1418 1419 1420 1421 1422 1423 1424 1425 1426 1427 1428 1429 1430 1431 1432 1433 1434 1435 1436 1437 1438 1439 1440 1441 1442 1443 1444 1445 1446 1447 1448 1449 1450 1451 1452 1453 1454 1455 1456 1457 1458 1459 1460 1461 | ** Return 0 if the input is not a well-formed JSON array. */ static void jsonArrayLengthFunc( sqlite3_context *ctx, int argc, sqlite3_value **argv ){ JsonParse *p; /* The parse */ sqlite3_int64 n = 0; u32 i; JsonNode *pNode; p = jsonParseCached(ctx, argv); if( p==0 ) return; assert( p->nNode ); if( argc==2 ){ const char *zPath = (const char*)sqlite3_value_text(argv[1]); pNode = jsonLookup(p, zPath, 0, ctx); }else{ pNode = p->aNode; } if( pNode==0 ){ return; } if( pNode->eType==JSON_ARRAY ){ assert( (pNode->jnFlags & JNODE_APPEND)==0 ); for(i=1; i<=pNode->n; n++){ i += jsonNodeSize(&pNode[i]); } } sqlite3_result_int64(ctx, n); } /* ** json_extract(JSON, PATH, ...) ** ** Return the element described by PATH. Return NULL if there is no ** PATH element. If there are multiple PATHs, then return a JSON array ** with the result from each path. Throw an error if the JSON or any PATH ** is malformed. */ static void jsonExtractFunc( sqlite3_context *ctx, int argc, sqlite3_value **argv ){ JsonParse *p; /* The parse */ JsonNode *pNode; const char *zPath; JsonString jx; int i; if( argc<2 ) return; p = jsonParseCached(ctx, argv); if( p==0 ) return; jsonInit(&jx, ctx); jsonAppendChar(&jx, '['); for(i=1; i<argc; i++){ zPath = (const char*)sqlite3_value_text(argv[i]); pNode = jsonLookup(p, zPath, 0, ctx); if( p->nErr ) break; if( argc>2 ){ jsonAppendSeparator(&jx); if( pNode ){ jsonRenderNode(pNode, &jx, 0); }else{ jsonAppendRaw(&jx, "null", 4); } }else if( pNode ){ jsonReturn(pNode, ctx, 0); } } if( argc>2 && i==argc ){ jsonAppendChar(&jx, ']'); jsonResult(&jx); sqlite3_result_subtype(ctx, JSON_SUBTYPE); } jsonReset(&jx); } /* This is the RFC 7396 MergePatch algorithm. */ static JsonNode *jsonMergePatch( JsonParse *pParse, /* The JSON parser that contains the TARGET */ u32 iTarget, /* Node of the TARGET in pParse */ |
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