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Add the JsonParse.zAlt field to old revised JSON text after a change.

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Demonstrate that this elminates the need for reparsing after a change
by using it in the json_remove() function.  This is an incremental check-in
containing lots of cruft.

FossilOrigin-Name: f930b139d6db0ee799bc90397b225175103c4bf22923d1c9cbcd32509adc1738
This commit is contained in:
drh
2023-07-26 00:48:45 +00:00
parent 59b8e666f6
commit 0f200bc580
6 changed files with 134 additions and 54 deletions
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146
src/json.c
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@@ -142,7 +142,8 @@ 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 */
char *zJson; /* Original JSON string */
char *zJson; /* Original JSON string (before edits) */
char *zAlt; /* Revised JSON after edits applied. Maybe NULL */
u32 *aUp; /* Index of parent of each node */
JsonTask *pClean; /* Cleanup operations prior to freeing this object */
u16 iDepth; /* Nesting depth */
@@ -151,8 +152,10 @@ struct JsonParse {
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 */
u8 useMod; /* Actually use the edits contain inside aNode */
u8 hasMod; /* aNode contains edits from the original zJson */
int nJson; /* Length of the zJson string in bytes */
int nAlt; /* Length of alternative JSON string zAlt, in bytes */
u32 iErr; /* Error location in zJson[] */
u32 iSubst; /* Last known JSON_SUBST node */
u32 iHold; /* Replace cache line with the lowest iHold value */
@@ -245,6 +248,16 @@ static int jsonGrow(JsonString *p, u32 N){
return SQLITE_OK;
}
/* Try to force the string to be an RCStr string, rather than a
** static string. Return true on success. The only reason this
** might fail is due to an OOM fault.
*/
static int jsonForceRCStr(JsonString *p){
if( p->bStatic==0 ) return 1;
jsonGrow(p, p->nAlloc+1);
return p->bStatic==0;
}
/* Append N bytes from zIn onto the end of the JsonString string.
*/
static SQLITE_NOINLINE void jsonAppendExpand(
@@ -588,6 +601,11 @@ static void jsonParseReset(JsonParse *pParse){
sqlite3_free(pParse->aUp);
pParse->aUp = 0;
}
if( pParse->zAlt ){
char *z = pParse->zAlt;
pParse->zAlt = 0;
sqlite3RCStrUnref(z);
}
if( pParse->bOwnsJson ){
/* Order operations so that if the destructor for pParse->zJson
** invokes jsonParseFree(), the recursion will terminate harmlessly */
@@ -650,7 +668,7 @@ static void jsonRenderNode(
JsonString *pOut /* Write JSON here */
){
assert( pNode!=0 );
while( (pNode->jnFlags & JNODE_REPLACE)!=0 ){
while( (pNode->jnFlags & JNODE_REPLACE)!=0 && pParse->useMod ){
u32 idx = (u32)(pNode - pParse->aNode);
u32 i = pParse->iSubst;
while( 1 /*exit-by-break*/ ){
@@ -722,13 +740,14 @@ static void jsonRenderNode(
jsonAppendChar(pOut, '[');
for(;;){
while( j<=pNode->n ){
if( (pNode[j].jnFlags & JNODE_REMOVE)==0 ){
if( (pNode[j].jnFlags & JNODE_REMOVE)==0 || pParse->useMod==0 ){
jsonAppendSeparator(pOut);
jsonRenderNode(pParse, &pNode[j], pOut);
}
j += jsonNodeSize(&pNode[j]);
}
if( (pNode->jnFlags & JNODE_APPEND)==0 ) break;
if( pParse->useMod==0 ) break;
assert( pNode->eU==2 );
pNode = &pParse->aNode[pNode->u.iAppend];
j = 1;
@@ -741,7 +760,7 @@ static void jsonRenderNode(
jsonAppendChar(pOut, '{');
for(;;){
while( j<=pNode->n ){
if( (pNode[j+1].jnFlags & JNODE_REMOVE)==0 ){
if( (pNode[j+1].jnFlags & JNODE_REMOVE)==0 || pParse->useMod==0 ){
jsonAppendSeparator(pOut);
jsonRenderNode(pParse, &pNode[j], pOut);
jsonAppendChar(pOut, ':');
@@ -750,6 +769,7 @@ static void jsonRenderNode(
j += 1 + jsonNodeSize(&pNode[j+1]);
}
if( (pNode->jnFlags & JNODE_APPEND)==0 ) break;
if( pParse->useMod==0 ) break;
assert( pNode->eU==2 );
pNode = &pParse->aNode[pNode->u.iAppend];
j = 1;
@@ -766,7 +786,8 @@ static void jsonRenderNode(
static void jsonReturnJson(
JsonParse *pParse, /* The complete JSON */
JsonNode *pNode, /* Node to return */
sqlite3_context *pCtx /* Return value for this function */
sqlite3_context *pCtx, /* Return value for this function */
int bGenerateAlt /* Also store the rendered text in zAlt */
){
JsonString s;
if( pParse->oom ){
@@ -776,6 +797,12 @@ static void jsonReturnJson(
if( pParse->nErr==0 ){
jsonInit(&s, pCtx);
jsonRenderNode(pParse, pNode, &s);
if( bGenerateAlt && pParse->zAlt==0 && jsonForceRCStr(&s) ){
jsonAppendChar(&s, 0);
s.nUsed--;
pParse->zAlt = sqlite3RCStrRef(s.zBuf);
pParse->nAlt = s.nUsed;
}
jsonResult(&s);
sqlite3_result_subtype(pCtx, JSON_SUBTYPE);
}
@@ -965,7 +992,7 @@ static void jsonReturn(
}
case JSON_ARRAY:
case JSON_OBJECT: {
jsonReturnJson(pParse, pNode, pCtx);
jsonReturnJson(pParse, pNode, pCtx, 0);
break;
}
}
@@ -1079,6 +1106,8 @@ static int jsonParseAddSubstNode(
pParse->aNode[idx].eU = 4;
pParse->aNode[idx].u.iPrev = pParse->iSubst;
pParse->iSubst = idx;
pParse->hasMod = 1;
pParse->useMod = 1;
return idx;
}
@@ -1729,6 +1758,7 @@ static int jsonParse(
int i;
memset(pParse, 0, sizeof(*pParse));
if( zJson==0 ) return 1;
//printf("PARSE %s\n", zJson);
pParse->zJson = zJson;
pParse->bOwnsJson = bTakeJson;
pParse->nJPRef = 1;
@@ -1837,9 +1867,10 @@ static int jsonParseFindParents(JsonParse *pParse){
** and so the caller must free it.
*/
static JsonParse *jsonParseCached(
sqlite3_context *pCtx,
sqlite3_value *pJson,
sqlite3_context *pErrCtx
sqlite3_context *pCtx, /* Context to use for cache search */
sqlite3_value *pJson, /* Function param containing JSON text */
sqlite3_context *pErrCtx, /* Write parse errors here if not NULL */
int bUnedited /* No prior edits allowed */
){
char *zJson = (char*)sqlite3_value_text(pJson);
int nJson = sqlite3_value_bytes(pJson);
@@ -1859,10 +1890,24 @@ static JsonParse *jsonParseCached(
}
if( pMatch==0
&& p->nJson==nJson
&& (p->hasMod==0 || bUnedited==0)
&& memcmp(p->zJson,zJson,nJson)==0
){
p->nErr = 0;
p->useMod = 0;
pMatch = p;
//printf("HIT %s at %d\n", zJson, iKey);
}else
if( pMatch==0
&& p->zAlt!=0
&& bUnedited==0
&& p->nAlt==nJson
&& memcmp(p->zAlt, zJson, nJson)==0
){
p->nErr = 0;
p->useMod = 1;
pMatch = p;
//printf("HIT %s at %d-alt\n", zJson, iKey);
}else if( p->iHold<iMinHold ){
iMinHold = p->iHold;
iMinKey = iKey;
@@ -1872,11 +1917,18 @@ static JsonParse *jsonParseCached(
}
}
if( pMatch ){
/* The input JSON text was found in the cache. Use the preexisting
** parse of this JSON */
pMatch->nErr = 0;
pMatch->iHold = iMaxHold+1;
assert( pMatch->nJPRef>0 ); /* pMatch is owned by the cache */
return pMatch;
}
/* The input JSON was not found anywhere in the cache. We will need
** to parse it ourselves and generate a new JsonParse object.
*/
//printf("MISS %s\n", zJson);
p = sqlite3_malloc64( sizeof(*p) );
if( p==0 ){
sqlite3_result_error_nomem(pCtx);
@@ -1954,7 +2006,7 @@ static JsonNode *jsonLookupStep(
u32 i, j, nKey;
const char *zKey;
JsonNode *pRoot = &pParse->aNode[iRoot];
while( (pRoot->jnFlags & JNODE_REPLACE)!=0 ){
while( (pRoot->jnFlags & JNODE_REPLACE)!=0 && pParse->useMod ){
u32 idx = (u32)(pRoot - pParse->aNode);
i = pParse->iSubst;
while( 1 /*exit-by-break*/ ){
@@ -2004,6 +2056,7 @@ static JsonNode *jsonLookupStep(
j += jsonNodeSize(&pRoot[j]);
}
if( (pRoot->jnFlags & JNODE_APPEND)==0 ) break;
if( pParse->useMod==0 ) break;
assert( pRoot->eU==2 );
iRoot = pRoot->u.iAppend;
pRoot = &pParse->aNode[iRoot];
@@ -2012,6 +2065,7 @@ static JsonNode *jsonLookupStep(
if( pApnd ){
u32 iStart, iLabel;
JsonNode *pNode;
assert( pParse->useMod );
iStart = jsonParseAddNode(pParse, JSON_OBJECT, 2, 0);
iLabel = jsonParseAddNode(pParse, JSON_STRING, nKey, zKey);
zPath += i;
@@ -2041,10 +2095,11 @@ static JsonNode *jsonLookupStep(
if( pRoot->eType!=JSON_ARRAY ) return 0;
for(;;){
while( j<=pBase->n ){
if( (pBase[j].jnFlags & JNODE_REMOVE)==0 ) i++;
if( (pBase[j].jnFlags & JNODE_REMOVE)==0 || pParse->useMod==0 ) i++;
j += jsonNodeSize(&pBase[j]);
}
if( (pBase->jnFlags & JNODE_APPEND)==0 ) break;
if( pParse->useMod==0 ) break;
assert( pBase->eU==2 );
iBase = pBase->u.iAppend;
pBase = &pParse->aNode[iBase];
@@ -2074,11 +2129,14 @@ static JsonNode *jsonLookupStep(
zPath += j + 1;
j = 1;
for(;;){
while( j<=pRoot->n && (i>0 || (pRoot[j].jnFlags & JNODE_REMOVE)!=0) ){
if( (pRoot[j].jnFlags & JNODE_REMOVE)==0 ) i--;
while( j<=pRoot->n
&& (i>0 || ((pRoot[j].jnFlags & JNODE_REMOVE)!=0 && pParse->useMod))
){
if( (pRoot[j].jnFlags & JNODE_REMOVE)==0 || pParse->useMod==0 ) i--;
j += jsonNodeSize(&pRoot[j]);
}
if( (pRoot->jnFlags & JNODE_APPEND)==0 ) break;
if( pParse->useMod==0 ) break;
assert( pRoot->eU==2 );
iRoot = pRoot->u.iAppend;
pRoot = &pParse->aNode[iRoot];
@@ -2090,6 +2148,7 @@ static JsonNode *jsonLookupStep(
if( i==0 && pApnd ){
u32 iStart;
JsonNode *pNode;
assert( pParse->useMod );
iStart = jsonParseAddNode(pParse, JSON_ARRAY, 1, 0);
pNode = jsonLookupAppend(pParse, zPath, pApnd, pzErr);
if( pParse->oom ) return 0;
@@ -2392,7 +2451,7 @@ static void jsonArrayLengthFunc(
u32 i;
JsonNode *pNode;
p = jsonParseCached(ctx, argv[0], ctx);
p = jsonParseCached(ctx, argv[0], ctx, 0);
if( p==0 ) return;
assert( p->nNode );
if( argc==2 ){
@@ -2405,9 +2464,14 @@ static void jsonArrayLengthFunc(
return;
}
if( pNode->eType==JSON_ARRAY ){
assert( (pNode->jnFlags & JNODE_APPEND)==0 );
for(i=1; i<=pNode->n; n++){
i += jsonNodeSize(&pNode[i]);
while( 1 /*exit-by-break*/ ){
for(i=1; i<=pNode->n; n++){
i += jsonNodeSize(&pNode[i]);
}
if( (pNode->jnFlags & JNODE_APPEND)==0 ) break;
if( p->useMod==0 ) break;
assert( pNode->eU==2 );
pNode = &p->aNode[pNode->u.iAppend];
}
}
sqlite3_result_int64(ctx, n);
@@ -2454,7 +2518,7 @@ static void jsonExtractFunc(
JsonString jx;
if( argc<2 ) return;
p = jsonParseCached(ctx, argv[0], ctx);
p = jsonParseCached(ctx, argv[0], ctx, 0);
if( p==0 ) return;
if( argc==2 ){
/* With a single PATH argument */
@@ -2487,7 +2551,7 @@ static void jsonExtractFunc(
}
if( pNode ){
if( flags & JSON_JSON ){
jsonReturnJson(p, pNode, ctx);
jsonReturnJson(p, pNode, ctx, 0);
}else{
jsonReturn(p, pNode, ctx);
sqlite3_result_subtype(ctx, 0);
@@ -2613,12 +2677,14 @@ static void jsonPatchFunc(
jsonParseReset(&x);
return;
}
x.useMod = 1;
y.useMod = 1;
pResult = jsonMergePatch(&x, 0, y.aNode);
assert( pResult!=0 || x.oom );
if( pResult && x.oom==0 ){
jsonDebugPrintParse(&x);
jsonDebugPrintNode(pResult);
jsonReturnJson(&x, pResult, ctx);
jsonReturnJson(&x, pResult, ctx, 0);
}else{
sqlite3_result_error_nomem(ctx);
}
@@ -2679,27 +2745,30 @@ static void jsonRemoveFunc(
int argc,
sqlite3_value **argv
){
JsonParse x; /* The parse */
JsonParse *pParse; /* The parse */
JsonNode *pNode;
const char *zPath;
u32 i;
if( argc<1 ) return;
if( jsonParse(&x, ctx, (char*)sqlite3_value_text(argv[0]), 0) ) return;
assert( x.nNode );
pParse = jsonParseCached(ctx, argv[0], ctx, argc>1);
if( pParse==0 ) return;
for(i=1; i<(u32)argc; i++){
zPath = (const char*)sqlite3_value_text(argv[i]);
if( zPath==0 ) goto remove_done;
pNode = jsonLookup(&x, zPath, 0, ctx);
if( x.nErr ) goto remove_done;
if( pNode ) pNode->jnFlags |= JNODE_REMOVE;
pNode = jsonLookup(pParse, zPath, 0, ctx);
if( pParse->nErr ) goto remove_done;
if( pNode ){
pNode->jnFlags |= JNODE_REMOVE;
pParse->hasMod = 1;
pParse->useMod = 1;
}
}
if( (x.aNode[0].jnFlags & JNODE_REMOVE)==0 ){
jsonReturnJson(&x, x.aNode, ctx);
if( (pParse->aNode[0].jnFlags & JNODE_REMOVE)==0 ){
jsonReturnJson(pParse, pParse->aNode, ctx, 1);
}
remove_done:
jsonDebugPrintParse(&x);
jsonParseReset(&x);
jsonDebugPrintParse(p);
}
/*
@@ -2763,7 +2832,7 @@ static void jsonReplaceNode(
sqlite3_result_error_nomem(pCtx);
}
}else{
JsonParse *pPatch = jsonParseCached(pCtx, pValue, pCtx);
JsonParse *pPatch = jsonParseCached(pCtx, pValue, pCtx, 1);
if( pPatch==0 ){
p->oom = 1;
break;
@@ -2817,7 +2886,7 @@ static void jsonReplaceFunc(
jsonReplaceNode(ctx, &x, (u32)(pNode - x.aNode), argv[i+1]);
}
}
jsonReturnJson(&x, x.aNode, ctx);
jsonReturnJson(&x, x.aNode, ctx, 0);
replace_err:
jsonDebugPrintParse(&x);
jsonParseReset(&x);
@@ -2858,6 +2927,7 @@ static void jsonSetFunc(
for(i=1; i<(u32)argc; i+=2){
zPath = (const char*)sqlite3_value_text(argv[i]);
bApnd = 0;
x.useMod = 1;
pNode = jsonLookup(&x, zPath, &bApnd, ctx);
if( x.oom ){
sqlite3_result_error_nomem(ctx);
@@ -2869,7 +2939,7 @@ static void jsonSetFunc(
}
}
jsonDebugPrintParse(&x);
jsonReturnJson(&x, x.aNode, ctx);
jsonReturnJson(&x, x.aNode, ctx, 0);
jsonSetDone:
jsonParseReset(&x);
@@ -2891,7 +2961,7 @@ static void jsonTypeFunc(
const char *zPath;
JsonNode *pNode;
p = jsonParseCached(ctx, argv[0], ctx);
p = jsonParseCached(ctx, argv[0], ctx, 0);
if( p==0 ) return;
if( argc==2 ){
zPath = (const char*)sqlite3_value_text(argv[1]);
@@ -2918,12 +2988,12 @@ static void jsonValidFunc(
JsonParse *p; /* The parse */
UNUSED_PARAMETER(argc);
if( sqlite3_value_type(argv[0])==SQLITE_NULL ) return;
p = jsonParseCached(ctx, argv[0], 0);
p = jsonParseCached(ctx, argv[0], 0, 0);
if( p==0 || p->oom ){
sqlite3_result_error_nomem(ctx);
sqlite3_free(p);
}else{
sqlite3_result_int(ctx, p->nErr==0 && p->hasNonstd==0);
sqlite3_result_int(ctx, p->nErr==0 && (p->hasNonstd==0 || p->useMod));
if( p->nErr ) jsonParseFree(p);
}
}
@@ -2964,7 +3034,7 @@ static void jsonErrorFunc(
JsonParse *p; /* The parse */
UNUSED_PARAMETER(argc);
if( sqlite3_value_type(argv[0])==SQLITE_NULL ) return;
p = jsonParseCached(ctx, argv[0], 0);
p = jsonParseCached(ctx, argv[0], 0, 0);
if( p==0 || p->oom ){
sqlite3_result_error_nomem(ctx);
sqlite3_free(p);