From 3e8a0fc522ee5bf7185a4b404c7f8a581129ed35 Mon Sep 17 00:00:00 2001
From: Lovell Fuller <github@lovell.info>
Date: Fri, 19 Apr 2024 11:27:51 +0100
Subject: [PATCH] Ensure only one StaySequential operation per pipeline

This should reduce memory consumption for more complex pipelines
that combine multiple operations without sequential access support
e.g. flip and Gaussian blur.
---
 src/common.cc | 6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)

diff --git a/src/common.cc b/src/common.cc
index 588b2a07e..ae48ff58a 100644
--- a/src/common.cc
+++ b/src/common.cc
@@ -1082,8 +1082,10 @@ namespace sharp {
     Ensure decoding remains sequential.
   */
   VImage StaySequential(VImage image, VipsAccess access, bool condition) {
-    if (access == VIPS_ACCESS_SEQUENTIAL && condition) {
-      return image.copy_memory();
+    static const char* meta = "sharp-copy-memory";
+    if (access == VIPS_ACCESS_SEQUENTIAL && condition && image.get_typeof(meta) != G_TYPE_INT) {
+      image = image.copy_memory();
+      image.set(meta, 1);
     }
     return image;
   }