1 files changed, 93 insertions, 12 deletions

diff --git a/src/backend/utils/adt/json.c b/src/backend/utils/adt/json.c
index d088fafc567..5edcb8bb60e 100644
--- a/src/backend/utils/adt/json.c
+++ b/src/backend/utils/adt/json.c
@@ -13,6 +13,7 @@
  */
 #include "postgres.h"
 
+#include "access/hash.h"
 #include "catalog/pg_proc.h"
 #include "catalog/pg_type.h"
 #include "common/hashfn.h"
@@ -1655,6 +1656,94 @@ escape_json(StringInfo buf, const char *str)
 	appendStringInfoCharMacro(buf, '"');
 }
 
+/* Semantic actions for key uniqueness check */
+static void
+json_unique_object_start(void *_state)
+{
+	JsonUniqueParsingState *state = _state;
+	JsonUniqueStackEntry *entry;
+
+	if (!state->unique)
+		return;
+
+	/* push object entry to stack */
+	entry = palloc(sizeof(*entry));
+	entry->object_id = state->id_counter++;
+	entry->parent = state->stack;
+	state->stack = entry;
+}
+
+static void
+json_unique_object_end(void *_state)
+{
+	JsonUniqueParsingState *state = _state;
+	JsonUniqueStackEntry *entry;
+
+	if (!state->unique)
+		return;
+
+	entry = state->stack;
+	state->stack = entry->parent;	/* pop object from stack */
+	pfree(entry);
+}
+
+static void
+json_unique_object_field_start(void *_state, char *field, bool isnull)
+{
+	JsonUniqueParsingState *state = _state;
+	JsonUniqueStackEntry *entry;
+
+	if (!state->unique)
+		return;
+
+	/* find key collision in the current object */
+	if (json_unique_check_key(&state->check, field, state->stack->object_id))
+		return;
+
+	state->unique = false;
+
+	/* pop all objects entries */
+	while ((entry = state->stack))
+	{
+		state->stack = entry->parent;
+		pfree(entry);
+	}
+}
+
+/* Validate JSON text and additionally check key uniqueness */
+bool
+json_validate(text *json, bool check_unique_keys)
+{
+	JsonLexContext *lex = makeJsonLexContext(json, check_unique_keys);
+	JsonSemAction uniqueSemAction = {0};
+	JsonUniqueParsingState state;
+	JsonParseErrorType result;
+
+	if (check_unique_keys)
+	{
+		state.lex = lex;
+		state.stack = NULL;
+		state.id_counter = 0;
+		state.unique = true;
+		json_unique_check_init(&state.check);
+
+		uniqueSemAction.semstate = &state;
+		uniqueSemAction.object_start = json_unique_object_start;
+		uniqueSemAction.object_field_start = json_unique_object_field_start;
+		uniqueSemAction.object_end = json_unique_object_end;
+	}
+
+	result = pg_parse_json(lex, check_unique_keys ? &uniqueSemAction : &nullSemAction);
+
+	if (result != JSON_SUCCESS)
+		return false;	/* invalid json */
+
+	if (check_unique_keys && !state.unique)
+		return false;	/* not unique keys */
+
+	return true;	/* ok */
+}
+
 /*
  * SQL function json_typeof(json) -> text
  *
@@ -1670,21 +1759,13 @@ escape_json(StringInfo buf, const char *str)
 Datum
 json_typeof(PG_FUNCTION_ARGS)
 {
-	text	   *json;
-
-	JsonLexContext *lex;
-	JsonTokenType tok;
+	text	   *json = PG_GETARG_TEXT_PP(0);
 	char	   *type;
-	JsonParseErrorType result;
-
-	json = PG_GETARG_TEXT_PP(0);
-	lex = makeJsonLexContext(json, false);
+	JsonTokenType tok;
 
 	/* Lex exactly one token from the input and check its type. */
-	result = json_lex(lex);
-	if (result != JSON_SUCCESS)
-		json_ereport_error(result, lex);
-	tok = lex->token_type;
+	tok = json_get_first_token(json, true);
+
 	switch (tok)
 	{
 		case JSON_TOKEN_OBJECT_START: