Add jsonb_canonical()

Nikita Glukhov · Nikita Glukhov · commit 525dbbfbadcb · 2017-05-02T21:38:28.000+03:00
diff --git a/src/backend/utils/adt/jsonb.c b/src/backend/utils/adt/jsonb.c
@@ -51,6 +51,13 @@ typedef enum					/* type categories for datum_to_jsonb */
 	JSONBTYPE_OTHER				/* all else */
 } JsonbTypeCategory;
 
+typedef enum
+{
+	JsonFormatCanonical,
+	JsonFormatNormal,
+	JsonFormatIndented
+} JsonFormat;
+
 typedef struct JsonbAggState
 {
 	JsonbInState *res;
@@ -85,7 +92,8 @@ static void datum_to_jsonb(Datum val, bool is_null, JsonbInState *result,
 			   bool key_scalar);
 static void add_jsonb(Datum val, bool is_null, JsonbInState *result,
 		  Oid val_type, bool key_scalar);
-static char *JsonbToCStringWorker(StringInfo out, JsonbContainer *in, int estimated_len, bool indent);
+static char *JsonbToCStringWorker(StringInfo out, JsonbContainer *in,
+								  int estimated_len, JsonFormat format);
 static void add_indent(StringInfo out, bool indent, int level);
 
 /*
@@ -399,7 +407,7 @@ jsonb_in_scalar(void *pstate, char *token, JsonTokenType tokentype)
 char *
 JsonbToCString(StringInfo out, JsonbContainer *in, int estimated_len)
 {
-	return JsonbToCStringWorker(out, in, estimated_len, false);
+	return JsonbToCStringWorker(out, in, estimated_len, JsonFormatNormal);
 }
 
 /*
@@ -408,14 +416,21 @@ JsonbToCString(StringInfo out, JsonbContainer *in, int estimated_len)
 char *
 JsonbToCStringIndent(StringInfo out, JsonbContainer *in, int estimated_len)
 {
-	return JsonbToCStringWorker(out, in, estimated_len, true);
+	return JsonbToCStringWorker(out, in, estimated_len, JsonFormatIndented);
+}
+
+char *
+JsonbToCStringCanonical(StringInfo out, JsonbContainer *in, int estimated_len)
+{
+	return JsonbToCStringWorker(out, in, estimated_len, JsonFormatCanonical);
 }
 
 /*
  * common worker for above two functions
  */
 static char *
-JsonbToCStringWorker(StringInfo out, JsonbContainer *in, int estimated_len, bool indent)
+JsonbToCStringWorker(StringInfo out, JsonbContainer *in, int estimated_len,
+					 JsonFormat format)
 {
 	bool		first = true;
 	JsonbIterator *it;
@@ -425,7 +440,8 @@ JsonbToCStringWorker(StringInfo out, JsonbContainer *in, int estimated_len, bool
 	bool		redo_switch = false;
 
 	/* If we are indenting, don't add a space after a comma */
-	int			ispaces = indent ? 1 : 2;
+	int			ispaces = format == JsonFormatNormal ? 2 : 1;
+	bool		indent = format == JsonFormatIndented;
 
 	/*
 	 * Don't indent the very first item. This gets set to the indent flag at
diff --git a/src/backend/utils/adt/jsonfuncs.c b/src/backend/utils/adt/jsonfuncs.c
@@ -4000,6 +4000,17 @@ jsonb_pretty(PG_FUNCTION_ARGS)
 	PG_RETURN_TEXT_P(cstring_to_text_with_len(str->data, str->len));
 }
 
+Datum
+jsonb_canonical(PG_FUNCTION_ARGS)
+{
+	Jsonb	   *jb = PG_GETARG_JSONB(0);
+	StringInfo	str = makeStringInfo();
+
+	JsonbToCStringCanonical(str, &jb->root, VARSIZE(jb));
+
+	PG_RETURN_TEXT_P(cstring_to_text_with_len(str->data, str->len));
+}
+
 /*
  * SQL function jsonb_concat (jsonb, jsonb)
  *
diff --git a/src/include/catalog/pg_proc.h b/src/include/catalog/pg_proc.h
@@ -5013,6 +5013,9 @@ DATA(insert OID = 3305 (  jsonb_set    PGNSP PGUID 12 1 0 0 0 f f f f t f i s 4
 DESCR("Set part of a jsonb");
 DATA(insert OID = 3306 (  jsonb_pretty	   PGNSP PGUID 12 1 0 0 0 f f f f t f i s 1 0 25 "3802" _null_ _null_ _null_ _null_ _null_ jsonb_pretty _null_ _null_ _null_ ));
 DESCR("Indented text from jsonb");
+DATA(insert OID = 3416 (  jsonb_canonical   PGNSP PGUID 12 1 0 0 0 f f f f t f i s 1 0 25 "3802" _null_ _null_ _null_ _null_ _null_ jsonb_canonical _null_ _null_ _null_ ));
+DESCR("Canonical text from jsonb");
+
 DATA(insert OID = 3579 (  jsonb_insert	  PGNSP PGUID 12 1 0 0 0 f f f f t f i s 4 0 3802 "3802 1009 3802 16" _null_ _null_ _null_ _null_ _null_ jsonb_insert _null_ _null_ _null_ ));
 DESCR("Insert value into a jsonb");
 /* txid */
diff --git a/src/include/utils/jsonb.h b/src/include/utils/jsonb.h
@@ -344,6 +344,7 @@ extern char *JsonbToCString(StringInfo out, JsonbContainer *in,
 			   int estimated_len);
 extern char *JsonbToCStringIndent(StringInfo out, JsonbContainer *in,
 					 int estimated_len);
-
+extern char *JsonbToCStringCanonical(StringInfo out, JsonbContainer *in,
+					 int estimated_len);
 
 #endif   /* __JSONB_H__ */
