From 34cd681a48b1cf597d04ca3f29b08326d81e3065 Mon Sep 17 00:00:00 2001
From: YimingWu <xp8110@outlook.com>
Date: Tue, 27 May 2025 10:01:41 +0200
Subject: [PATCH] Fix #139387: Try to handle mmap exception on Win32

`IMB_load_image_from_file_descriptor` use mmap to read images, and mmap
sometimes can have erroreous state llike accessing a file from network
drives. This patch tries to handle these exceptions like `BLI_mmap_read`
on Win32 (On unix the `sigbus_handler` will be called instead).

Pull Request: https://projects.blender.org/blender/blender/pulls/139472
---
 source/blender/blenlib/BLI_mmap.h         |  1 +
 source/blender/blenlib/intern/BLI_mmap.cc |  5 +++++
 source/blender/imbuf/intern/readimage.cc  | 26 ++++++++++++++++++++++-
 3 files changed, 31 insertions(+), 1 deletion(-)

diff --git a/source/blender/blenlib/BLI_mmap.h b/source/blender/blenlib/BLI_mmap.h
index 2a8f507f5c2..4f775b20dd0 100644
--- a/source/blender/blenlib/BLI_mmap.h
+++ b/source/blender/blenlib/BLI_mmap.h
@@ -30,5 +30,6 @@ bool BLI_mmap_read(BLI_mmap_file *file, void *dest, size_t offset, size_t length
 
 void *BLI_mmap_get_pointer(BLI_mmap_file *file) ATTR_WARN_UNUSED_RESULT;
 size_t BLI_mmap_get_length(const BLI_mmap_file *file) ATTR_WARN_UNUSED_RESULT;
+bool BLI_mmap_any_io_error(const BLI_mmap_file *file) ATTR_WARN_UNUSED_RESULT;
 
 void BLI_mmap_free(BLI_mmap_file *file) ATTR_NONNULL(1);
diff --git a/source/blender/blenlib/intern/BLI_mmap.cc b/source/blender/blenlib/intern/BLI_mmap.cc
index 5317e7935ba..e3c1ce9d43e 100644
--- a/source/blender/blenlib/intern/BLI_mmap.cc
+++ b/source/blender/blenlib/intern/BLI_mmap.cc
@@ -219,6 +219,11 @@ size_t BLI_mmap_get_length(const BLI_mmap_file *file)
   return file->length;
 }
 
+bool BLI_mmap_any_io_error(const BLI_mmap_file *file)
+{
+  return file->io_error;
+}
+
 void BLI_mmap_free(BLI_mmap_file *file)
 {
 #ifndef WIN32
diff --git a/source/blender/imbuf/intern/readimage.cc b/source/blender/imbuf/intern/readimage.cc
index b58fe7d12ec..ca3f4e13c23 100644
--- a/source/blender/imbuf/intern/readimage.cc
+++ b/source/blender/imbuf/intern/readimage.cc
@@ -7,6 +7,7 @@
  */
 
 #ifdef _WIN32
+#  include <exception>
 #  include <io.h>
 #  include <stddef.h>
 #  include <sys/types.h>
@@ -167,7 +168,30 @@ ImBuf *IMB_load_image_from_file_descriptor(const int file,
   const uchar *mem = static_cast<const uchar *>(BLI_mmap_get_pointer(mmap_file));
   const size_t size = BLI_mmap_get_length(mmap_file);
 
-  ibuf = IMB_load_image_from_memory(mem, size, flags, filepath, filepath, r_colorspace);
+  /* There could be broken mmap due to network drives and other issues, handles exception the
+   * same way as in #BLI_mmap_read. Note that if the mmap becomes invalid mid-way through reading,
+   * external calls in #IMB_load_image_from_memory could leave unfreed memory, but this is the
+   * limitation of current exception handling method. Ref #139472. */
+#ifdef WIN32
+  __try
+  {
+#endif
+
+    ibuf = IMB_load_image_from_memory(mem, size, flags, filepath, filepath, r_colorspace);
+
+#ifdef WIN32
+  }
+  __except (GetExceptionCode() == EXCEPTION_IN_PAGE_ERROR ? EXCEPTION_EXECUTE_HANDLER :
+                                                            EXCEPTION_CONTINUE_SEARCH)
+  {
+    ibuf = nullptr;
+  }
+#else
+  /* For unix, if mmap encounters an exception, BLI_mmap_file::io_error would be set. */
+  if (BLI_mmap_any_io_error(mmap_file)) {
+    ibuf = nullptr;
+  }
+#endif
 
   imb_mmap_lock();
   BLI_mmap_free(mmap_file);