Add jsonb_insert

It inserts a new value into an jsonb array at arbitrary position or
a new key to jsonb object.

Author: Dmitry Dolgov
Reviewers: Petr Jelinek, Vitaly Burovoy, Andrew Dunstan

1 files changed, 110 insertions, 24 deletions

diff --git a/src/backend/utils/adt/jsonfuncs.c b/src/backend/utils/adt/jsonfuncs.c
index 97e0e8e0596..fb149dcd477 100644
--- a/src/backend/utils/adt/jsonfuncs.c
+++ b/src/backend/utils/adt/jsonfuncs.c
@@ -33,6 +33,15 @@
 #include "utils/memutils.h"
 #include "utils/typcache.h"
 
+/* Operations available for setPath */
+#define JB_PATH_NOOP					0x0000
+#define JB_PATH_CREATE					0x0001
+#define JB_PATH_DELETE					0x0002
+#define JB_PATH_INSERT_BEFORE			0x0004
+#define JB_PATH_INSERT_AFTER			0x0008
+#define JB_PATH_CREATE_OR_INSERT \
+	(JB_PATH_INSERT_BEFORE | JB_PATH_INSERT_AFTER | JB_PATH_CREATE)
+
 /* semantic action functions for json_object_keys */
 static void okeys_object_field_start(void *state, char *fname, bool isnull);
 static void okeys_array_start(void *state);
@@ -130,14 +139,14 @@ static JsonbValue *IteratorConcat(JsonbIterator **it1, JsonbIterator **it2,
 static JsonbValue *setPath(JsonbIterator **it, Datum *path_elems,
 		bool *path_nulls, int path_len,
 		JsonbParseState **st, int level, Jsonb *newval,
-		bool create);
+		int op_type);
 static void setPathObject(JsonbIterator **it, Datum *path_elems,
 			  bool *path_nulls, int path_len, JsonbParseState **st,
 			  int level,
-			  Jsonb *newval, uint32 npairs, bool create);
+			  Jsonb *newval, uint32 npairs, int op_type);
 static void setPathArray(JsonbIterator **it, Datum *path_elems,
 			 bool *path_nulls, int path_len, JsonbParseState **st,
-			 int level, Jsonb *newval, uint32 nelems, bool create);
+			 int level, Jsonb *newval, uint32 nelems, int op_type);
 static void addJsonbToParseState(JsonbParseState **jbps, Jsonb *jb);
 
 /* state for json_object_keys */
@@ -3544,7 +3553,7 @@ jsonb_set(PG_FUNCTION_ARGS)
 	it = JsonbIteratorInit(&in->root);
 
 	res = setPath(&it, path_elems, path_nulls, path_len, &st,
-				  0, newval, create);
+				  0, newval, create ? JB_PATH_CREATE : JB_PATH_NOOP);
 
 	Assert(res != NULL);
 
@@ -3588,7 +3597,52 @@ jsonb_delete_path(PG_FUNCTION_ARGS)
 
 	it = JsonbIteratorInit(&in->root);
 
-	res = setPath(&it, path_elems, path_nulls, path_len, &st, 0, NULL, false);
+	res = setPath(&it, path_elems, path_nulls, path_len, &st,
+				  0, NULL, JB_PATH_DELETE);
+
+	Assert(res != NULL);
+
+	PG_RETURN_JSONB(JsonbValueToJsonb(res));
+}
+
+/*
+ * SQL function jsonb_insert(jsonb, text[], jsonb, boolean)
+ *
+ */
+Datum
+jsonb_insert(PG_FUNCTION_ARGS)
+{
+	Jsonb	   *in = PG_GETARG_JSONB(0);
+	ArrayType  *path = PG_GETARG_ARRAYTYPE_P(1);
+	Jsonb	   *newval = PG_GETARG_JSONB(2);
+	bool		after = PG_GETARG_BOOL(3);
+	JsonbValue *res = NULL;
+	Datum	   *path_elems;
+	bool	   *path_nulls;
+	int			path_len;
+	JsonbIterator *it;
+	JsonbParseState *st = NULL;
+
+	if (ARR_NDIM(path) > 1)
+		ereport(ERROR,
+				(errcode(ERRCODE_ARRAY_SUBSCRIPT_ERROR),
+				 errmsg("wrong number of array subscripts")));
+
+	if (JB_ROOT_IS_SCALAR(in))
+		ereport(ERROR,
+				(errcode(ERRCODE_INVALID_PARAMETER_VALUE),
+				 errmsg("cannot set path in scalar")));
+
+	deconstruct_array(path, TEXTOID, -1, false, 'i',
+					  &path_elems, &path_nulls, &path_len);
+
+	if (path_len == 0)
+		PG_RETURN_JSONB(in);
+
+	it = JsonbIteratorInit(&in->root);
+
+	res = setPath(&it, path_elems, path_nulls, path_len, &st, 0, newval,
+				  after ? JB_PATH_INSERT_AFTER : JB_PATH_INSERT_BEFORE);
 
 	Assert(res != NULL);
 
@@ -3707,18 +3761,23 @@ IteratorConcat(JsonbIterator **it1, JsonbIterator **it2,
 }
 
 /*
- * Do most of the heavy work for jsonb_set
+ * Do most of the heavy work for jsonb_set/jsonb_insert
+ *
+ * If JB_PATH_DELETE bit is set in op_type, the element is to be removed.
  *
- * If newval is null, the element is to be removed.
+ * If any bit mentioned in JB_PATH_CREATE_OR_INSERT is set in op_type,
+ * we create the new value if the key or array index does not exist.
  *
- * If create is true, we create the new value if the key or array index
- * does not exist. All path elements before the last must already exist
- * whether or not create is true, or nothing is done.
+ * Bits JB_PATH_INSERT_BEFORE and JB_PATH_INSERT_AFTER in op_type
+ * behave as JB_PATH_CREATE if new value is inserted in JsonbObject.
+ *
+ * All path elements before the last must already exist
+ * whatever bits in op_type are set, or nothing is done.
  */
 static JsonbValue *
 setPath(JsonbIterator **it, Datum *path_elems,
 		bool *path_nulls, int path_len,
-		JsonbParseState **st, int level, Jsonb *newval, bool create)
+		JsonbParseState **st, int level, Jsonb *newval, int op_type)
 {
 	JsonbValue	v;
 	JsonbIteratorToken r;
@@ -3739,7 +3798,7 @@ setPath(JsonbIterator **it, Datum *path_elems,
 		case WJB_BEGIN_ARRAY:
 			(void) pushJsonbValue(st, r, NULL);
 			setPathArray(it, path_elems, path_nulls, path_len, st, level,
-						 newval, v.val.array.nElems, create);
+						 newval, v.val.array.nElems, op_type);
 			r = JsonbIteratorNext(it, &v, false);
 			Assert(r == WJB_END_ARRAY);
 			res = pushJsonbValue(st, r, NULL);
@@ -3747,7 +3806,7 @@ setPath(JsonbIterator **it, Datum *path_elems,
 		case WJB_BEGIN_OBJECT:
 			(void) pushJsonbValue(st, r, NULL);
 			setPathObject(it, path_elems, path_nulls, path_len, st, level,
-						  newval, v.val.object.nPairs, create);
+						  newval, v.val.object.nPairs, op_type);
 			r = JsonbIteratorNext(it, &v, true);
 			Assert(r == WJB_END_OBJECT);
 			res = pushJsonbValue(st, r, NULL);
@@ -3771,7 +3830,7 @@ setPath(JsonbIterator **it, Datum *path_elems,
 static void
 setPathObject(JsonbIterator **it, Datum *path_elems, bool *path_nulls,
 			  int path_len, JsonbParseState **st, int level,
-			  Jsonb *newval, uint32 npairs, bool create)
+			  Jsonb *newval, uint32 npairs, int op_type)
 {
 	JsonbValue	v;
 	int			i;
@@ -3782,7 +3841,8 @@ setPathObject(JsonbIterator **it, Datum *path_elems, bool *path_nulls,
 		done = true;
 
 	/* empty object is a special case for create */
-	if ((npairs == 0) && create && (level == path_len - 1))
+	if ((npairs == 0) && (op_type & JB_PATH_CREATE_OR_INSERT) &&
+		(level == path_len - 1))
 	{
 		JsonbValue	newkey;
 
@@ -3807,8 +3867,19 @@ setPathObject(JsonbIterator **it, Datum *path_elems, bool *path_nulls,
 		{
 			if (level == path_len - 1)
 			{
-				r = JsonbIteratorNext(it, &v, true);	/* skip */
-				if (newval != NULL)
+				/*
+				 * called from jsonb_insert(), it forbids redefining
+				 * an existsing value
+				 */
+				if (op_type & (JB_PATH_INSERT_BEFORE | JB_PATH_INSERT_AFTER))
+					ereport(ERROR,
+							(errcode(ERRCODE_INVALID_PARAMETER_VALUE),
+							 errmsg("cannot replace existing key"),
+							 errhint("Try using the function jsonb_set "
+									 "to replace key value.")));
+
+				r = JsonbIteratorNext(it, &v, true); /* skip value */
+				if (!(op_type & JB_PATH_DELETE))
 				{
 					(void) pushJsonbValue(st, WJB_KEY, &k);
 					addJsonbToParseState(st, newval);
@@ -3819,12 +3890,13 @@ setPathObject(JsonbIterator **it, Datum *path_elems, bool *path_nulls,
 			{
 				(void) pushJsonbValue(st, r, &k);
 				setPath(it, path_elems, path_nulls, path_len,
-						st, level + 1, newval, create);
+						st, level + 1, newval, op_type);
 			}
 		}
 		else
 		{
-			if (create && !done && level == path_len - 1 && i == npairs - 1)
+			if ((op_type & JB_PATH_CREATE_OR_INSERT) && !done &&
+				level == path_len - 1 && i == npairs - 1)
 			{
 				JsonbValue	newkey;
 
@@ -3865,7 +3937,7 @@ setPathObject(JsonbIterator **it, Datum *path_elems, bool *path_nulls,
 static void
 setPathArray(JsonbIterator **it, Datum *path_elems, bool *path_nulls,
 			 int path_len, JsonbParseState **st, int level,
-			 Jsonb *newval, uint32 nelems, bool create)
+			 Jsonb *newval, uint32 nelems, int op_type)
 {
 	JsonbValue	v;
 	int			idx,
@@ -3909,7 +3981,8 @@ setPathArray(JsonbIterator **it, Datum *path_elems, bool *path_nulls,
 	 * what the idx value is
 	 */
 
-	if ((idx == INT_MIN || nelems == 0) && create && (level == path_len - 1))
+	if ((idx == INT_MIN || nelems == 0) && (level == path_len - 1) &&
+		(op_type & JB_PATH_CREATE_OR_INSERT))
 	{
 		Assert(newval != NULL);
 		addJsonbToParseState(st, newval);
@@ -3926,14 +3999,26 @@ setPathArray(JsonbIterator **it, Datum *path_elems, bool *path_nulls,
 			if (level == path_len - 1)
 			{
 				r = JsonbIteratorNext(it, &v, true);	/* skip */
-				if (newval != NULL)
+
+				if (op_type & (JB_PATH_INSERT_BEFORE | JB_PATH_CREATE))
+					addJsonbToParseState(st, newval);
+
+				/*
+				 * We should keep current value only in case of
+				 * JB_PATH_INSERT_BEFORE or JB_PATH_INSERT_AFTER
+				 * because otherwise it should be deleted or replaced
+				 */
+				if (op_type & (JB_PATH_INSERT_AFTER | JB_PATH_INSERT_BEFORE))
+					(void) pushJsonbValue(st, r, &v);
+
+				if (op_type & JB_PATH_INSERT_AFTER)
 					addJsonbToParseState(st, newval);
 
 				done = true;
 			}
 			else
 				(void) setPath(it, path_elems, path_nulls, path_len,
-							   st, level + 1, newval, create);
+							   st, level + 1, newval, op_type);
 		}
 		else
 		{
@@ -3958,7 +4043,8 @@ setPathArray(JsonbIterator **it, Datum *path_elems, bool *path_nulls,
 				}
 			}
 
-			if (create && !done && level == path_len - 1 && i == nelems - 1)
+			if (op_type & JB_PATH_CREATE_OR_INSERT && !done &&
+				level == path_len - 1 && i == nelems - 1)
 			{
 				addJsonbToParseState(st, newval);
 			}