Add JsonValueUnwrap(), JsonExtractScalar()

Nikita Glukhov · Nikita Glukhov · commit f168b8b28647 · 2022-07-27T00:46:12.000+03:00
diff --git a/src/backend/utils/adt/json_generic.c b/src/backend/utils/adt/json_generic.c
@@ -103,6 +103,52 @@ JsonValueCopy(JsonValue *res, const JsonValue *val)
 	return res;
 }
 
+JsonValue *
+JsonExtractScalar(JsonContainer *jc, JsonValue *scalar)
+{
+	JsonIterator   *it;
+	JsonValue		val;
+
+	Assert(JsonContainerIsScalar(jc));
+
+	it = JsonIteratorInit(jc);
+
+	if (JsonIteratorNext(&it, &val, false) != WJB_BEGIN_ARRAY ||
+		JsonIteratorNext(&it, scalar, false) != WJB_ELEM ||
+		JsonIteratorNext(&it, &val, false) != WJB_END_ARRAY)
+		elog(ERROR, "unexpected structure of scalar json container");
+
+	return scalar;
+}
+
+const JsonValue *
+JsonValueUnwrap(const JsonValue *val, JsonValue *valbuf)
+{
+	if (val->type == jbvBinary)
+	{
+		JsonContainer *jc = val->val.binary.data;
+
+		if (jc->ops == &jsonvContainerOps)
+		{
+			val = (JsonbValue *) jc->data;
+			Assert(val->type != jbvBinary);
+		}
+		else if (JsonContainerIsScalar(jc))
+		{
+			val = JsonExtractScalar(jc, valbuf);
+			Assert(IsAJsonbScalar(val));
+		}
+	}
+
+	if (val->type == jbvArray && val->val.array.rawScalar)
+	{
+		val = &val->val.array.elems[0];
+		Assert(IsAJsonbScalar(val));
+	}
+
+	return val;
+}
+
 static inline JsonValue *
 jsonFindKeyInObjectInternal(JsonContainer *obj, const char *key, int len,
 							bool last)
diff --git a/src/backend/utils/adt/jsonb.c b/src/backend/utils/adt/jsonb.c
@@ -846,15 +846,10 @@ datum_to_jsonb(Datum val, bool is_null, JsonbInState *result,
 			case JSONBTYPE_JSONB:
 				{
 					Jsonb	   *jsonb = DatumGetJsonbP(val);
-					JsonbIterator *it;
-
-					it = JsonbIteratorInit(&jsonb->root);
 
 					if (JB_ROOT_IS_SCALAR(jsonb))
 					{
-						(void) JsonbIteratorNext(&it, &jb, true);
-						Assert(jb.type == jbvArray);
-						(void) JsonbIteratorNext(&it, &jb, true);
+						JsonExtractScalar(&jsonb->root, &jb);
 						break;
 					}
 
@@ -866,6 +861,7 @@ datum_to_jsonb(Datum val, bool is_null, JsonbInState *result,
 					else
 					{
 						JsonbIteratorToken type;
+						JsonbIterator *it = JsonbIteratorInit(&jsonb->root);
 
 						while ((type = JsonbIteratorNext(&it, &jb, false))
 							   != WJB_DONE)
diff --git a/src/backend/utils/adt/jsonb_util.c b/src/backend/utils/adt/jsonb_util.c
@@ -747,6 +747,16 @@ pushJsonbValueExt(JsonbParseState **pstate, JsonbIteratorToken seq,
 		jbval->type != jbvBinary || !unpackBinary)
 	{
 		/* drop through */
+		if (jbval && (seq == WJB_ELEM || seq == WJB_VALUE))
+			jbval = JsonValueUnwrap(jbval, &v);
+
+		return pushJsonbValueScalar(pstate, seq, jbval);
+	}
+
+	if (*pstate && JsonContainerIsScalar(jbval->val.binary.data))
+	{
+		jbval = JsonExtractScalar(jbval->val.binary.data, &v);
+		Assert(IsAJsonbScalar(jbval));
 		return pushJsonbValueScalar(pstate, seq, jbval);
 	}
 
diff --git a/src/include/utils/json_generic.h b/src/include/utils/json_generic.h
@@ -271,7 +271,9 @@ extern JsonValue *JsonToJsonValue(Json *json, JsonValue *jv);
 extern JsonValue *JsonValueUnpackBinary(const JsonValue *jbv);
 extern JsonContainer *JsonValueToContainer(const JsonValue *val);
 extern JsonValue *JsonValueCopy(JsonValue *res, const JsonValue *val);
+extern const JsonValue *JsonValueUnwrap(const JsonValue *val, JsonValue *buf);
 extern JsonContainer *JsonCopyFlat(JsonContainer *flatContainer);
+extern JsonValue *JsonExtractScalar(JsonContainer *jc, JsonValue *scalar);
 
 extern Jsonb *JsonbMakeEmptyArray(void);
 extern Jsonb *JsonbMakeEmptyObject(void);

Original file line number	Diff line number	Diff line change
`@@ -846,15 +846,10 @@ datum_to_jsonb(Datum val, bool is_null, JsonbInState *result,`
`846`	`846`	`case JSONBTYPE_JSONB:`
`847`	`847`	`{`
`848`	`848`	`Jsonb *jsonb = DatumGetJsonbP(val);`
`849`		`- JsonbIterator *it;`
`850`		`-`
`851`		`- it = JsonbIteratorInit(&jsonb->root);`
`852`	`849`
`853`	`850`	`if (JB_ROOT_IS_SCALAR(jsonb))`
`854`	`851`	`{`
`855`		`- (void) JsonbIteratorNext(&it, &jb, true);`
`856`		`- Assert(jb.type == jbvArray);`
`857`		`- (void) JsonbIteratorNext(&it, &jb, true);`
	`852`	`+ JsonExtractScalar(&jsonb->root, &jb);`
`858`	`853`	`break;`
`859`	`854`	`}`
`860`	`855`
`@@ -866,6 +861,7 @@ datum_to_jsonb(Datum val, bool is_null, JsonbInState *result,`
`866`	`861`	`else`
`867`	`862`	`{`
`868`	`863`	`JsonbIteratorToken type;`
	`864`	`+ JsonbIterator *it = JsonbIteratorInit(&jsonb->root);`
`869`	`865`
`870`	`866`	`while ((type = JsonbIteratorNext(&it, &jb, false))`
`871`	`867`	`!= WJB_DONE)`