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Improved comments and other cleanup for the changes on this branch.

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FossilOrigin-Name: bac953a80d1a541e7a12aef00c86c002133859237143ad670b39ea19799a8900
This commit is contained in:
drh
2023-07-26 11:43:39 +00:00
parent 9a184daad3
commit 7725370ff4
3 changed files with 93 additions and 95 deletions
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174
src/json.c
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@@ -59,7 +59,7 @@ static const char jsonIsSpace[] = {
typedef struct JsonString JsonString;
typedef struct JsonNode JsonNode;
typedef struct JsonParse JsonParse;
typedef struct JsonTask JsonTask;
typedef struct JsonCleanup JsonCleanup;
/* An instance of this object represents a JSON string
** under construction. Really, this is a generic string accumulator
@@ -75,11 +75,11 @@ struct JsonString {
char zSpace[100]; /* Initial static space */
};
/* A deferred cleanup task. A list of JsonTask objects might be
/* A deferred cleanup task. A list of JsonCleanup objects might be
** run when the JsonParse object is destroyed.
*/
struct JsonTask {
JsonTask *pJTNext; /* Next in a list */
struct JsonCleanup {
JsonCleanup *pJCNext; /* Next in a list */
void (*xOp)(void*); /* Routine to run */
void *pArg; /* Argument to xOp() */
};
@@ -136,29 +136,50 @@ struct JsonNode {
};
/* A completely parsed JSON string
/* 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.
**
** 2. Zero or more changes are made (via json_remove() or json_replace()
** or similar) to the aNode[] array.
**
** 3. A new, edited and mimified JSON string is generated from aNode
** and stored in zAlt. The JsonParse object always owns zAlt.
**
** Step 1 always happens. Step 2 and 3 may or may not happen, depending
** on the operation.
**
** aNode[].u.zJContent entries typically point into zJson. Hence zJson
** must remain valid for the lifespan of the parse. For edits,
** aNode[].u.zJContent might point to malloced space other than zJson.
** Entries in pClup are responsible for freeing that extra malloced space.
**
** When walking the parse tree in aNode[], edits are ignored if useMod is
** false.
*/
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 (before edits) */
char *zAlt; /* Revised JSON after edits applied. Maybe NULL */
char *zAlt; /* Revised and/or mimified JSON */
u32 *aUp; /* Index of parent of each node */
JsonTask *pClean; /* Cleanup operations prior to freeing this object */
JsonCleanup *pClup;/* Cleanup operations prior to freeing this object */
u16 iDepth; /* Nesting depth */
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 nJPRef; /* Number of references to this object */
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 */
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 */
u32 iSubst; /* Last JSON_SUBST entry in aNode[] */
u32 iHold; /* Age of this entry in the cache for LRU replacement */
};
/*
@@ -174,17 +195,6 @@ struct JsonParse {
** Utility routines for dealing with JsonString objects
**************************************************************************/
#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 jsonStringClass(void *p){
sqlite3RCStrUnref((char*)p);
}
#endif
/* Set the JsonString object to an empty string
*/
static void jsonZero(JsonString *p){
@@ -202,7 +212,6 @@ static void jsonInit(JsonString *p, sqlite3_context *pCtx){
jsonZero(p);
}
/* Free all allocated memory and reset the JsonString object back to its
** initial state.
*/
@@ -211,8 +220,7 @@ static void jsonReset(JsonString *p){
jsonZero(p);
}
/* Report an out-of-memory (OOM) condition
/* Report an out-of-memory (OOM) condition
*/
static void jsonOom(JsonString *p){
p->bErr = 1;
@@ -316,7 +324,9 @@ static int jsonForceRCStr(JsonString *p){
p->nUsed--;
if( p->bStatic==0 ) return 1;
p->nAlloc = 0;
p->nUsed++;
jsonGrow(p, p->nUsed);
p->nUsed--;
return p->bStatic==0;
}
@@ -392,7 +402,7 @@ static void jsonAppendNormalizedString(JsonString *p, const char *zIn, u32 N){
jsonAppendRawNZ(p, zIn, i);
zIn += i;
N -= i;
if( N==0 ) break;
if( N==0 ) break;
}
assert( zIn[0]=='\\' );
switch( (u8)zIn[1] ){
@@ -501,7 +511,7 @@ static void jsonAppendNormalizedReal(JsonString *p, const char *zIn, u32 N){
/*
** Append a function parameter value to the JSON string under
** Append a function parameter value to the JSON string under
** construction.
*/
static void jsonAppendValue(
@@ -550,18 +560,11 @@ static void jsonAppendValue(
** The JSON string is reset.
*/
static void jsonResult(JsonString *p){
if( p->bErr==0 ){
if( p->bStatic ){
sqlite3_result_text64(p->pCtx, p->zBuf, p->nUsed, SQLITE_TRANSIENT,
SQLITE_UTF8);
}else{
jsonAppendChar(p, 0);
p->nUsed--;
sqlite3RCStrRef(p->zBuf);
sqlite3_result_text64(p->pCtx, p->zBuf, p->nUsed,
(void(*)(void*))sqlite3RCStrUnref,
SQLITE_UTF8);
}
if( p->bErr==0 && jsonForceRCStr(p) ){
sqlite3RCStrRef(p->zBuf);
sqlite3_result_text64(p->pCtx, p->zBuf, p->nUsed,
(void(*)(void*))sqlite3RCStrUnref,
SQLITE_UTF8);
}else if( p->bErr==1 ){
sqlite3_result_error_nomem(p->pCtx);
}
@@ -590,9 +593,9 @@ static u32 jsonNodeSize(JsonNode *pNode){
** delete the JsonParse object itself.
*/
static void jsonParseReset(JsonParse *pParse){
while( pParse->pClean ){
JsonTask *pTask = pParse->pClean;
pParse->pClean = pTask->pJTNext;
while( pParse->pClup ){
JsonCleanup *pTask = pParse->pClup;
pParse->pClup = pTask->pJCNext;
pTask->xOp(pTask->pArg);
sqlite3_free(pTask);
}
@@ -608,17 +611,13 @@ static void jsonParseReset(JsonParse *pParse){
pParse->aUp = 0;
}
if( pParse->zAlt ){
char *z = pParse->zAlt;
sqlite3RCStrUnref(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 */
char *z = pParse->zJson;
pParse->zJson = 0;
pParse->bOwnsJson = 0;
sqlite3RCStrUnref(z);
sqlite3RCStrUnref(pParse->zJson);
pParse->zJson = 0;
}
}
@@ -650,14 +649,14 @@ static int jsonParseAddCleanup(
void(*xOp)(void*), /* The cleanup task */
void *pArg /* Argument to the cleanup */
){
JsonTask *pTask = sqlite3_malloc64( sizeof(*pTask) );
JsonCleanup *pTask = sqlite3_malloc64( sizeof(*pTask) );
if( pTask==0 ){
pParse->oom = 1;
xOp(pArg);
return SQLITE_ERROR;
}
pTask->pJTNext = pParse->pClean;
pParse->pClean = pTask;
pTask->pJCNext = pParse->pClup;
pParse->pClup = pTask;
pTask->xOp = xOp;
pTask->pArg = pArg;
return SQLITE_OK;
@@ -870,8 +869,7 @@ static void jsonReturn(
int rc;
int bNeg = 0;
const char *z;
assert( pNode->eU==1 );
z = pNode->u.zJContent;
if( z[0]=='-' ){ z++; bNeg = 1; }
@@ -1458,23 +1456,23 @@ json_parse_restart:
cDelim = z[i];
for(j=i+1; 1; j++){
static const char aOk[256] = {
0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
1, 1, 0, 1, 1, 1, 1, 0, 1, 1, 1, 1, 1, 1, 1, 1,
1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1,
1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1,
1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 0, 1, 1, 1,
1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1,
1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1,
0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
1, 1, 0, 1, 1, 1, 1, 0, 1, 1, 1, 1, 1, 1, 1, 1,
1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1,
1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1,
1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 0, 1, 1, 1,
1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1,
1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1,
1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1,
1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1,
1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1,
1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1,
1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1,
1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1,
1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1,
1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1
1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1,
1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1,
1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1,
1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1,
1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1,
1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1,
1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1,
1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1,
};
if( aOk[(unsigned char)z[j]] ) continue;
c = z[j];
@@ -1740,18 +1738,18 @@ json_parse_restart:
/*
** Parse a complete JSON string. Return 0 on success or non-zero if there
** are any errors. If an error occurs, free all memory associated with
** pParse.
** are any errors. If an error occurs, free all memory held by pParse,
** but not pParse itself.
**
** pParse is uninitialized when this routine is called.
**
** pParse->nJPRef set to 1. The caller becomes the owner of the
** pParse->nJPRef set to 1. The caller becomes the owner of the
** the JsonParse object.
**
** pParse->bOwnsJson is to bTakeJson. If bTakeJson is 1, the newly initialized
** JsonParse object will become the own the zJson input string. If bTakeJson
** is 0, then the caller is responsible for preserving zJson for the lifetime
** of the JsonParse object.
** pParse->bOwnsJson is set to bTakeJson. If bTakeJson is 1, the newly
** initialized JsonParse object will become the owner of the zJson input
** string. If bTakeJson is 0, then the caller is responsible for
** preserving zJson for the lifetime of the JsonParse object.
*/
static int jsonParse(
JsonParse *pParse, /* Initialize and fill this JsonParse object */
@@ -2129,7 +2127,7 @@ static JsonNode *jsonLookupStep(
zPath += j + 1;
j = 1;
for(;;){
while( j<=pRoot->n
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--;
@@ -2255,7 +2253,7 @@ static void jsonWrongNumArgs(
char *zMsg = sqlite3_mprintf("json_%s() needs an odd number of arguments",
zFuncName);
sqlite3_result_error(pCtx, zMsg, -1);
sqlite3_free(zMsg);
sqlite3_free(zMsg);
}
/*
@@ -2391,7 +2389,7 @@ static void jsonTest1Func(
/*
** Implementation of the json_QUOTE(VALUE) function. Return a JSON value
** corresponding to the SQL value input. Mostly this means putting
** corresponding to the SQL value input. Mostly this means putting
** double-quotes around strings and returning the unquoted string "null"
** when given a NULL input.
*/
@@ -2438,7 +2436,7 @@ static void jsonArrayFunc(
** json_array_length(JSON)
** json_array_length(JSON, PATH)
**
** Return the number of elements in the top-level JSON array.
** Return the number of elements in the top-level JSON array.
** Return 0 if the input is not a well-formed JSON array.
*/
static void jsonArrayLengthFunc(
@@ -2752,7 +2750,7 @@ static void jsonRemoveFunc(
if( argc<1 ) return;
pParse = jsonParseCached(ctx, argv[0], ctx, argc>1);
if( pParse==0 ) return;
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;
@@ -2854,7 +2852,7 @@ static void jsonReplaceNode(
}
}
}
/*
** json_replace(JSON, PATH, VALUE, ...)
**
@@ -3269,7 +3267,7 @@ static int jsonEachConnect(
UNUSED_PARAMETER(argv);
UNUSED_PARAMETER(argc);
UNUSED_PARAMETER(pAux);
rc = sqlite3_declare_vtab(db,
rc = sqlite3_declare_vtab(db,
"CREATE TABLE x(key,value,type,atom,id,parent,fullkey,path,"
"json HIDDEN,root HIDDEN)");
if( rc==SQLITE_OK ){
@@ -3481,7 +3479,7 @@ static int jsonEachColumn(
break;
}
case JEACH_ID: {
sqlite3_result_int64(ctx,
sqlite3_result_int64(ctx,
(sqlite3_int64)p->i + ((pThis->jnFlags & JNODE_LABEL)!=0));
break;
}
@@ -3581,8 +3579,8 @@ static int jsonEachBestIndex(
idxMask |= iMask;
}
}
if( pIdxInfo->nOrderBy>0
&& pIdxInfo->aOrderBy[0].iColumn<0
if( pIdxInfo->nOrderBy>0
&& pIdxInfo->aOrderBy[0].iColumn<0
&& pIdxInfo->aOrderBy[0].desc==0
){
pIdxInfo->orderByConsumed = 1;
@@ -3782,10 +3780,10 @@ void sqlite3RegisterJsonFunctions(void){
JFUNCTION(json_parse, 1, 0, jsonParseFunc),
JFUNCTION(json_test1, 1, 0, jsonTest1Func),
#endif
WAGGREGATE(json_group_array, 1, 0, 0,
WAGGREGATE(json_group_array, 1, 0, 0,
jsonArrayStep, jsonArrayFinal, jsonArrayValue, jsonGroupInverse,
SQLITE_SUBTYPE|SQLITE_UTF8|SQLITE_DETERMINISTIC),
WAGGREGATE(json_group_object, 2, 0, 0,
WAGGREGATE(json_group_object, 2, 0, 0,
jsonObjectStep, jsonObjectFinal, jsonObjectValue, jsonGroupInverse,
SQLITE_SUBTYPE|SQLITE_UTF8|SQLITE_DETERMINISTIC)
};