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Reduce the number of memory allocations when parsing JSON.

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FossilOrigin-Name: 9edd67162113df57dae21d4683f9495611e2cf4717c6d12f5b7b8e44156d5fe3
This commit is contained in:
drh
2023-07-26 23:22:32 +00:00
parent f7a164f345
commit e94e132994
3 changed files with 15 additions and 30 deletions
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31
src/json.c
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@@ -144,8 +144,7 @@ struct JsonNode {
/* A parsed and possibly edited JSON string. Lifecycle:
**
** 1. JSON comes in and is parsed into an array aNode[]. The original
** JSON text is stored in zJson. This object may or may not be the
** owner of the input JSON - the bOwnsJson variables determines which.
** JSON text is stored in zJson.
**
** 2. Zero or more changes are made (via json_remove() or json_replace()
** or similar) to the aNode[] array.
@@ -176,7 +175,6 @@ struct JsonParse {
u8 nErr; /* Number of errors seen */
u8 oom; /* Set to true if out of memory */
u8 hasNonstd; /* True if input uses non-standard features like JSON5 */
u8 bOwnsJson; /* This object owns zJson and response for freeing it */
u8 useMod; /* Actually use the edits contain inside aNode */
u8 hasMod; /* aNode contains edits from the original zJson */
u32 nJPRef; /* Number of references to this object */
@@ -619,11 +617,6 @@ static void jsonParseReset(JsonParse *pParse){
sqlite3RCStrUnref(pParse->zAlt);
pParse->zAlt = 0;
}
if( pParse->bOwnsJson ){
pParse->bOwnsJson = 0;
sqlite3RCStrUnref(pParse->zJson);
pParse->zJson = 0;
}
}
/*
@@ -1759,14 +1752,12 @@ json_parse_restart:
static int jsonParse(
JsonParse *pParse, /* Initialize and fill this JsonParse object */
sqlite3_context *pCtx, /* Report errors here */
char *zJson, /* Input JSON text to be parsed */
int bTakeJson /* Assume ownership of zJson if true */
char *zJson /* Input JSON text to be parsed */
){
int i;
memset(pParse, 0, sizeof(*pParse));
if( zJson==0 ) return 1;
pParse->zJson = zJson;
pParse->bOwnsJson = bTakeJson;
pParse->nJPRef = 1;
i = jsonParseValue(pParse, 0);
if( pParse->oom ) i = -1;
@@ -1933,21 +1924,16 @@ static JsonParse *jsonParseCached(
/* The input JSON was not found anywhere in the cache. We will need
** to parse it ourselves and generate a new JsonParse object.
*/
p = sqlite3_malloc64( sizeof(*p) );
p = sqlite3_malloc64( sizeof(*p) + nJson + 1 );
if( p==0 ){
sqlite3_result_error_nomem(pCtx);
return 0;
}
memset(p, 0, sizeof(*p));
p->zJson = sqlite3RCStrNew( nJson );
if( p->zJson==0 ){
sqlite3_free(p);
sqlite3_result_error_nomem(pCtx);
return 0;
}
p->zJson = (char*)&p[1];
memcpy(p->zJson, zJson, nJson);
p->zJson[nJson] = 0;
if( jsonParse(p, pErrCtx, p->zJson, 1) ){
if( jsonParse(p, pErrCtx, p->zJson) ){
if( pErrCtx==0 ){
p->nErr = 1;
assert( p->nJPRef==1 ); /* Caller will own the new JsonParse object p */
@@ -2365,7 +2351,6 @@ static void jsonParseFunc(
printf("nErr = %u\n", p->nErr);
printf("oom = %u\n", p->oom);
printf("hasNonstd = %u\n", p->hasNonstd);
printf("bOwnsJson = %u\n", p->bOwnsJson);
printf("useMod = %u\n", p->useMod);
printf("hasMod = %u\n", p->hasMod);
printf("nJPRef = %u\n", p->nJPRef);
@@ -2677,8 +2662,8 @@ static void jsonPatchFunc(
JsonNode *pResult; /* The result of the merge */
UNUSED_PARAMETER(argc);
if( jsonParse(&x, ctx, (char*)sqlite3_value_text(argv[0]), 0) ) return;
if( jsonParse(&y, ctx, (char*)sqlite3_value_text(argv[1]), 0) ){
if( jsonParse(&x, ctx, (char*)sqlite3_value_text(argv[0])) ) return;
if( jsonParse(&y, ctx, (char*)sqlite3_value_text(argv[1])) ){
jsonParseReset(&x);
return;
}
@@ -3645,7 +3630,7 @@ static int jsonEachFilter(
p->zJson = sqlite3_malloc64( n+1 );
if( p->zJson==0 ) return SQLITE_NOMEM;
memcpy(p->zJson, z, (size_t)n+1);
if( jsonParse(&p->sParse, 0, p->zJson, 0) ){
if( jsonParse(&p->sParse, 0, p->zJson) ){
int rc = SQLITE_NOMEM;
if( p->sParse.oom==0 ){
sqlite3_free(cur->pVtab->zErrMsg);