v1-0001-refactor-function-range_leftover_internal.patch

From 5cdd99f9a63d381985541b0df539c2bb92ef7276 Mon Sep 17 00:00:00 2001
From: pgaddict <jian.universality@gmail.com>
Date: Sat, 21 Oct 2023 17:18:50 +0800
Subject: [PATCH v1 1/1] refactor function range_leftover_internal

renaming variable.
better comment.

---
 src/backend/utils/adt/rangetypes.c | 55 +++++++++++++++++-------------
 src/include/utils/rangetypes.h     |  5 ++-
 2 files changed, 33 insertions(+), 27 deletions(-)

diff --git a/src/backend/utils/adt/rangetypes.c b/src/backend/utils/adt/rangetypes.c
index d4e17323..a5a34450 100644
--- a/src/backend/utils/adt/rangetypes.c
+++ b/src/backend/utils/adt/rangetypes.c
@@ -1207,47 +1207,54 @@ range_split_internal(TypeCacheEntry *typcache, const RangeType *r1, const RangeT
 }
 
 /*
- * range_leftover_internal - Sets output1 and output2 to the remaining parts of r1
- * after subtracting r2, or if nothing is left then to the empty range.
- * output1 will always be "before" r2 and output2 "after".
+ * Sets leftoverRange and rightoverRange to the remaining parts of oldRange
+ * after subtracting targetRange, or if nothing is left then to the empty range.
+ * leftoverRange will always be "before" targetRange and rightoverRange "after" targetRange.
  */
 void
-range_leftover_internal(TypeCacheEntry *typcache, const RangeType *r1,
-						const RangeType *r2, RangeType **output1, RangeType **output2)
+range_leftover_internal(TypeCacheEntry *typcache, const RangeType *oldRange,
+						const RangeType *targetRange, RangeType **leftoverRange, RangeType **rightoverRange)
 {
-	RangeBound	lower1,
-				lower2;
-	RangeBound	upper1,
-				upper2;
-	bool		empty1,
-				empty2;
+	RangeBound	lower_oldRange,
+				lower_targetRange;
+	RangeBound	upper_oldRange,
+				upper_targetRange;
+	bool		oldRange_is_empty,
+				targetRange_is_empty;
 
-	range_deserialize(typcache, r1, &lower1, &upper1, &empty1);
-	range_deserialize(typcache, r2, &lower2, &upper2, &empty2);
+	range_deserialize(typcache, oldRange, &lower_oldRange, &upper_oldRange, &oldRange_is_empty);
+	range_deserialize(typcache, targetRange, &lower_targetRange, &upper_targetRange, &targetRange_is_empty);
 
-	if (range_cmp_bounds(typcache, &lower1, &lower2) < 0)
+	/*
+	* FOR PORTION OF. upper_targetRange, if oldRange do not overlaps with targetRangeType.
+	* So these two range must overlaps, that means both range should not be empty.
+	*
+	*/
+	Assert(!oldRange_is_empty);
+	Assert(!targetRange_is_empty);
+
+	if (range_cmp_bounds(typcache, &lower_oldRange, &lower_targetRange) < 0)
 	{
-		lower2.inclusive = !lower2.inclusive;
-		lower2.lower = false;
-		*output1 = make_range(typcache, &lower1, &lower2, false, NULL);
+		lower_targetRange.inclusive = !lower_targetRange.inclusive;
+		lower_targetRange.lower = false;
+		*leftoverRange = make_range(typcache, &lower_oldRange, &lower_targetRange, false, NULL);
 	}
 	else
 	{
-		*output1 = make_empty_range(typcache);
+		*leftoverRange = make_empty_range(typcache);
 	}
 
-	if (range_cmp_bounds(typcache, &upper1, &upper2) > 0)
+	if (range_cmp_bounds(typcache, &upper_oldRange, &upper_targetRange) > 0)
 	{
-		upper2.inclusive = !upper2.inclusive;
-		upper2.lower = true;
-		*output2 = make_range(typcache, &upper2, &upper1, false, NULL);
+		upper_targetRange.inclusive = !upper_targetRange.inclusive;
+		upper_targetRange.lower = true;
+		*rightoverRange = make_range(typcache, &upper_targetRange, &upper_oldRange, false, NULL);
 	}
 	else
 	{
-		*output2 = make_empty_range(typcache);
+		*rightoverRange = make_empty_range(typcache);
 	}
 }
-
 /* range -> range aggregate functions */
 
 Datum
diff --git a/src/include/utils/rangetypes.h b/src/include/utils/rangetypes.h
index 48ee2deb..f67ae402 100644
--- a/src/include/utils/rangetypes.h
+++ b/src/include/utils/rangetypes.h
@@ -164,8 +164,7 @@ extern RangeType *make_empty_range(TypeCacheEntry *typcache);
 extern bool range_split_internal(TypeCacheEntry *typcache, const RangeType *r1,
 								 const RangeType *r2, RangeType **output1,
 								 RangeType **output2);
-extern void range_leftover_internal(TypeCacheEntry *typcache, const RangeType *r1,
-									const RangeType *r2, RangeType **output1,
-									RangeType **output2);
+extern void range_leftover_internal(TypeCacheEntry *typcache, const RangeType *oldRange,
+						const RangeType *targetRange, RangeType **leftoverRange, RangeType **rightoverRange);
 
 #endif							/* RANGETYPES_H */
-- 
2.34.1