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Incremental improvements to JSON parsing - trying to fold in the RCStr object.

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FossilOrigin-Name: 4cb15d934a85ebc290fe6dd8cd3bd47b159561ca75d72bbffef30b9ea4623b09
This commit is contained in:
drh
2023-07-25 18:28:03 +00:00
parent 4bca124845
commit 440e696d5e
3 changed files with 166 additions and 32 deletions
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184
src/json.c
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@@ -142,7 +142,7 @@ struct JsonParse {
u32 nNode; /* Number of slots of aNode[] used */
u32 nAlloc; /* Number of slots of aNode[] allocated */
JsonNode *aNode; /* Array of nodes containing the parse */
const char *zJson; /* Original JSON string */
char *zJson; /* Original JSON string */
u32 *aUp; /* Index of parent of each node */
JsonTask *pClean; /* Cleanup operations prior to freeing this object */
u16 iDepth; /* Nesting depth */
@@ -150,6 +150,8 @@ struct JsonParse {
u8 oom; /* Set to true if out of memory */
u8 hasNonstd; /* True if input uses non-standard features like JSON5 */
u8 nJPRef; /* Number of references to this object */
u8 bOwnsJson; /* This object owns zJson and response for freeing it */
u8 isMod; /* aNode contains edits from the original zJson */
int nJson; /* Length of the zJson string in bytes */
u32 iErr; /* Error location in zJson[] */
u32 iSubst; /* Last known JSON_SUBST node */
@@ -565,24 +567,41 @@ static void jsonParseReset(JsonParse *pParse){
sqlite3_free(pTask);
}
assert( pParse->nJPRef<=1 );
sqlite3_free(pParse->aNode);
pParse->aNode = 0;
if( pParse->aNode ){
sqlite3_free(pParse->aNode);
pParse->aNode = 0;
}
pParse->nNode = 0;
pParse->nAlloc = 0;
sqlite3_free(pParse->aUp);
pParse->aUp = 0;
if( pParse->aUp ){
sqlite3_free(pParse->aUp);
pParse->aUp = 0;
}
if( pParse->bOwnsJson ){
/* Order operations so that if the destructor for pParse->zJson
** invokes jsonParseFree(), the recursion will terminate harmlessly */
char *z = pParse->zJson;
pParse->zJson = 0;
pParse->bOwnsJson = 0;
sqlite3RCStrUnref(z);
}
}
/*
** Free a JsonParse object that was obtained from sqlite3_malloc().
**
** Note that destroying JsonParse might call sqlite3RCStrUnref() to
** destroy the zJson value. The RCStr object might recursively invoke
** JsonParse to destroy this pParse object again. Take care to ensure
** that this recursive destructor sequence terminates harmlessly.
*/
static void jsonParseFree(JsonParse *pParse){
if( pParse->nJPRef>1 ){
pParse->nJPRef--;
return;
}else{
jsonParseReset(pParse);
sqlite3_free(pParse);
}
jsonParseReset(pParse);
sqlite3_free(pParse);
}
/*
@@ -1218,7 +1237,7 @@ static const struct NanInfName {
**
** Special return values:
**
** 0 End if input
** 0 End of input
** -1 Syntax error
** -2 '}' seen
** -3 ']' seen
@@ -1685,7 +1704,7 @@ json_parse_restart:
static int jsonParse(
JsonParse *pParse, /* Initialize and fill this JsonParse object */
sqlite3_context *pCtx, /* Report errors here */
const char *zJson /* Input JSON text to be parsed */
char *zJson /* Input JSON text to be parsed */
){
int i;
memset(pParse, 0, sizeof(*pParse));
@@ -1719,6 +1738,121 @@ static int jsonParse(
return 0;
}
#if 0
/*
** This is a destructor for JSON strings. We make it a separate function
** so that the sqlite3ValueIsOfClass() function can be used to unambiguously
** identify sqlite3_value objects that are known JSON strings.
*/
static void jsonClass(void *p){
sqlite3RCStrUnref((char*)p);
}
#endif
#if 0
/*
** Process SQL function argument pJson as a JSON string. Return a pointer
** to its parse.
**
** If any error is encountered, return a NULL pointer and leave an error
** message in pCtx.
*/
static JsonParse *jsonParseFromFunctionArg(
sqlite3_value *pJson, /* An SQL function argument containing JSON */
sqlite3_context *pCtx, /* For accessing the cache */
sqlite3_context *pErrCtx, /* For reporting errors */
int bUnchng /* Only accept cached parse that are unchanged */
){
JsonParse *pParse;
char *zJson;
int nJson;
JsonParse *pMatch = 0;
int iKey;
int iMinKey = 0;
u32 iMinHold = 0xffffffff;
u32 iMaxHold = 0;
char *zJson = (char*)sqlite3_value_text(pJson);
int nJson = sqlite3_value_bytes(pJson);
if( zJson==0 ) goto json_parse_value_nomem;
if( sqlite3ValueIsOfClass(pJson, jsonClass) ){
assert( zJson!=0 );
(void)sqlite3RCStrRef(zJson);
pParse = sqlite3RCStrGetAttachment(zJson, (void(*)(void*)jsonParseFree);
if( pParse ){
return pParse;
}
}else{
char *z = zJson;
zJson = sqlite3RCStrNew( nJson );
if( zJson==0 ) goto json_parse_value_nomem;
assert( strlen(z)==nJson );
memcpy(zJson, z, nJson+1);
}
/* At this point zJson is an RCStr object that does not yet have a
** parse. This procedure is holding its own reference to that zJson
** and needs to release it, or hand it off, prior to returning.
**
** The next step is to try to find a parse of the JSON that already
** exists in cache.
*/
for(iKey=0; iKey<JSON_CACHE_SZ; iKey++){
JsonParse *p;
p = (JsonParse*)sqlite3_get_auxdata(pCtx, JSON_CACHE_ID+iKey);
if( p==0 ){
iMinKey = iKey;
break;
}
if( pMatch==0
&& p->nJson==nJson
&& (p->isMod==0 || bUnchng==0)
&& memcmp(p->zJson,zJson,nJson)==0
){
p->nErr = 0;
pMatch = p;
}else if( p->iHold<iMinHold ){
iMinHold = p->iHold;
iMinKey = iKey;
}
if( p->iHold>iMaxHold ){
iMaxHold = p->iHold;
}
}
if( pMatch ){
pParse = pMatch;
pParse->iHold = iMaxHold+1;
}else{
/* No parse of zJson could be found in cache. So parse it afresh.
*/
pParse = sqlite3_malloc64( sizeof(JsonParse) );
if( pParse==0 ) goto json_parse_value_nomem;
if( jsonParse(pParse, pCtx, zJson) ){
sqlite3_free(pParse);
sqlite3RCStrUnref(zJson);
return 0;
}
pParse->bOwnsJson = 1;
pParse->nJson = nJson;
pParse->nJPRef = 1;
pParse->iHold = iMaxHold+1;
sqlite3_set_auxdata(pCtx, JSON_CACHE_ID+iMinKey, pParse,
(void(*)(void*))jsonParseFree);
pParse = (JsonParse*)sqlite3_get_auxdata(pCtx, JSON_CACHE_ID+iMinKey);
}
if( pParse ){
pParse->nJPRef++; /* The caller will own this object */
}
return pParse;
json_parse_value_nomem:
if( zJson ) sqlite3RCStrUnref(zJson);
if( pErrCtx ) sqlite3_result_error_nomem(pCtx);
return 0;
}
#endif
/* Mark node i of pParse as being a child of iParent. Call recursively
** to fill in all the descendants of node i.
*/
@@ -1786,11 +1920,11 @@ static int jsonParseFindParents(JsonParse *pParse){
*/
static JsonParse *jsonParseCached(
sqlite3_context *pCtx,
sqlite3_value **argv,
sqlite3_value *pJson,
sqlite3_context *pErrCtx
){
const char *zJson = (const char*)sqlite3_value_text(argv[0]);
int nJson = sqlite3_value_bytes(argv[0]);
char *zJson = (char*)sqlite3_value_text(pJson);
int nJson = sqlite3_value_bytes(pJson);
JsonParse *p;
JsonParse *pMatch = 0;
int iKey;
@@ -2223,7 +2357,7 @@ static void jsonParseFunc(
u32 i;
assert( argc==1 );
if( jsonParse(&x, ctx, (const char*)sqlite3_value_text(argv[0])) ) return;
if( jsonParse(&x, ctx, (char*)sqlite3_value_text(argv[0])) ) return;
jsonParseFindParents(&x);
jsonInit(&s, ctx);
for(i=0; i<x.nNode; i++){
@@ -2331,7 +2465,7 @@ static void jsonArrayLengthFunc(
u32 i;
JsonNode *pNode;
p = jsonParseCached(ctx, argv, ctx);
p = jsonParseCached(ctx, argv[0], ctx);
if( p==0 ) return;
assert( p->nNode );
if( argc==2 ){
@@ -2393,7 +2527,7 @@ static void jsonExtractFunc(
JsonString jx;
if( argc<2 ) return;
p = jsonParseCached(ctx, argv, ctx);
p = jsonParseCached(ctx, argv[0], ctx);
if( p==0 ) return;
if( argc==2 ){
/* With a single PATH argument */
@@ -2547,8 +2681,8 @@ static void jsonPatchFunc(
JsonNode *pResult; /* The result of the merge */
UNUSED_PARAMETER(argc);
if( jsonParse(&x, ctx, (const char*)sqlite3_value_text(argv[0])) ) return;
if( jsonParse(&y, ctx, (const char*)sqlite3_value_text(argv[1])) ){
if( jsonParse(&x, ctx, (char*)sqlite3_value_text(argv[0])) ) return;
if( jsonParse(&y, ctx, (char*)sqlite3_value_text(argv[1])) ){
jsonParseReset(&x);
return;
}
@@ -2624,7 +2758,7 @@ static void jsonRemoveFunc(
u32 i;
if( argc<1 ) return;
if( jsonParse(&x, ctx, (const char*)sqlite3_value_text(argv[0])) ) return;
if( jsonParse(&x, ctx, (char*)sqlite3_value_text(argv[0])) ) return;
assert( x.nNode );
for(i=1; i<(u32)argc; i++){
zPath = (const char*)sqlite3_value_text(argv[i]);
@@ -2702,7 +2836,7 @@ static void jsonReplaceNode(
sqlite3_result_error_nomem(pCtx);
}
}else{
JsonParse *pPatch = jsonParseCached(pCtx, &pValue, pCtx);
JsonParse *pPatch = jsonParseCached(pCtx, pValue, pCtx);
if( pPatch==0 ){
p->oom = 1;
break;
@@ -2746,7 +2880,7 @@ static void jsonReplaceFunc(
jsonWrongNumArgs(ctx, "replace");
return;
}
if( jsonParse(&x, ctx, (const char*)sqlite3_value_text(argv[0])) ) return;
if( jsonParse(&x, ctx, (char*)sqlite3_value_text(argv[0])) ) return;
assert( x.nNode );
for(i=1; i<(u32)argc; i+=2){
zPath = (const char*)sqlite3_value_text(argv[i]);
@@ -2792,7 +2926,7 @@ static void jsonSetFunc(
jsonWrongNumArgs(ctx, bIsSet ? "set" : "insert");
return;
}
if( jsonParse(&x, ctx, (const char*)sqlite3_value_text(argv[0])) ) return;
if( jsonParse(&x, ctx, (char*)sqlite3_value_text(argv[0])) ) return;
assert( x.nNode );
for(i=1; i<(u32)argc; i+=2){
zPath = (const char*)sqlite3_value_text(argv[i]);
@@ -2830,7 +2964,7 @@ static void jsonTypeFunc(
const char *zPath;
JsonNode *pNode;
p = jsonParseCached(ctx, argv, ctx);
p = jsonParseCached(ctx, argv[0], ctx);
if( p==0 ) return;
if( argc==2 ){
zPath = (const char*)sqlite3_value_text(argv[1]);
@@ -2857,7 +2991,7 @@ static void jsonValidFunc(
JsonParse *p; /* The parse */
UNUSED_PARAMETER(argc);
if( sqlite3_value_type(argv[0])==SQLITE_NULL ) return;
p = jsonParseCached(ctx, argv, 0);
p = jsonParseCached(ctx, argv[0], 0);
if( p==0 || p->oom ){
sqlite3_result_error_nomem(ctx);
sqlite3_free(p);
@@ -2903,7 +3037,7 @@ static void jsonErrorFunc(
JsonParse *p; /* The parse */
UNUSED_PARAMETER(argc);
if( sqlite3_value_type(argv[0])==SQLITE_NULL ) return;
p = jsonParseCached(ctx, argv, 0);
p = jsonParseCached(ctx, argv[0], 0);
if( p==0 || p->oom ){
sqlite3_result_error_nomem(ctx);
sqlite3_free(p);