From d00ca333c338b40911e89939c3cc771025978595 Mon Sep 17 00:00:00 2001
From: Magnus Hagander <magnus@hagander.net>
Date: Wed, 18 Jan 2017 21:37:59 +0100
Subject: Implement array version of jsonb_delete and operator

This makes it possible to delete multiple keys from a jsonb value by
passing in an array of text values, which makes the operaiton much
faster than individually deleting the keys (which would require copying
the jsonb structure over and over again.

Reviewed by Dmitry Dolgov and Michael Paquier
---
 src/backend/utils/adt/jsonfuncs.c | 86 +++++++++++++++++++++++++++++++++++++++
 1 file changed, 86 insertions(+)

(limited to 'src/backend/utils/adt/jsonfuncs.c')

diff --git a/src/backend/utils/adt/jsonfuncs.c b/src/backend/utils/adt/jsonfuncs.c
index 58c721c074e..d624fdbf79c 100644
--- a/src/backend/utils/adt/jsonfuncs.c
+++ b/src/backend/utils/adt/jsonfuncs.c
@@ -3437,6 +3437,92 @@ jsonb_delete(PG_FUNCTION_ARGS)
 	PG_RETURN_JSONB(JsonbValueToJsonb(res));
 }
 
+/*
+ * SQL function jsonb_delete (jsonb, variadic text[])
+ *
+ * return a copy of the jsonb with the indicated items
+ * removed.
+ */
+Datum
+jsonb_delete_array(PG_FUNCTION_ARGS)
+{
+	Jsonb	   *in = PG_GETARG_JSONB(0);
+	ArrayType  *keys = PG_GETARG_ARRAYTYPE_P(1);
+	Datum	   *keys_elems;
+	bool	   *keys_nulls;
+	int			keys_len;
+	JsonbParseState *state = NULL;
+	JsonbIterator *it;
+	JsonbValue	v,
+			   *res = NULL;
+	bool		skipNested = false;
+	JsonbIteratorToken r;
+
+	if (ARR_NDIM(keys) > 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 delete from scalar")));
+
+	if (JB_ROOT_COUNT(in) == 0)
+		PG_RETURN_JSONB(in);
+
+	deconstruct_array(keys, TEXTOID, -1, false, 'i',
+					  &keys_elems, &keys_nulls, &keys_len);
+
+	if (keys_len == 0)
+		PG_RETURN_JSONB(in);
+
+	it = JsonbIteratorInit(&in->root);
+
+	while ((r = JsonbIteratorNext(&it, &v, skipNested)) != 0)
+	{
+		skipNested = true;
+
+		if ((r == WJB_ELEM || r == WJB_KEY) && v.type == jbvString)
+		{
+			int			i;
+			bool		found = false;
+
+			for (i = 0; i < keys_len; i++)
+			{
+				char	   *keyptr;
+				int			keylen;
+
+				if (keys_nulls[i])
+					continue;
+
+				keyptr = VARDATA_ANY(keys_elems[i]);
+				keylen = VARSIZE_ANY_EXHDR(keys_elems[i]);
+				if (keylen == v.val.string.len &&
+					memcmp(keyptr, v.val.string.val, keylen) == 0)
+				{
+					found = true;
+					break;
+				}
+			}
+			if (found)
+			{
+				/* skip corresponding value as well */
+				if (r == WJB_KEY)
+					JsonbIteratorNext(&it, &v, true);
+
+				continue;
+			}
+		}
+
+		res = pushJsonbValue(&state, r, r < WJB_BEGIN_ARRAY ? &v : NULL);
+	}
+
+	Assert(res != NULL);
+
+	PG_RETURN_JSONB(JsonbValueToJsonb(res));
+}
+
 /*
  * SQL function jsonb_delete (jsonb, int)
  *
-- 
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