wt/cpp-httplib
1
0 Fork 0
mirror of https://github.com/yhirose/cpp-httplib.git synced 2026-10-24 12:04:40 +00:00
Code Issues Packages Projects Releases Wiki Activity

Fix #2435: allow mmap to open files held open for writing (#2438)

Browse Source 
* Add test for #2435 mmap::open with concurrent writer

Verifies that detail::mmap can open a file held open with GENERIC_WRITE
by another handle (e.g. an active log file). Currently fails on Windows
because CreateFile2 omits FILE_SHARE_WRITE.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

* Fix #2435: allow mmap to open files held open for writing

Add FILE_SHARE_WRITE to the share mode passed to ::CreateFile2 so
detail::mmap can open a file even when another process holds it open
with GENERIC_WRITE (e.g. an active log file). Without this, CreateFile2
fails with ERROR_SHARING_VIOLATION because the new opener's share mode
must permit the existing handle's access mode.

This brings the Windows path's behavior in line with the POSIX path
which uses ::open(O_RDONLY) and is unaffected by other processes'
write handles.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

---------

Co-authored-by: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
This commit is contained in:
yhiroseandClaude Opus 4.7 authored and GitHub committed 2026-04-29 12:42:38 +09:00
1 parent 0cbeafe6a4
commit c2678f0186
2 files changed
+28 -2
Download Patch File Download Diff File Expand all files Collapse all files

No files matched your search

httplib.h
+3 -2
View File
@@ -5319,8 +5319,9 @@ inline bool mmap::open(const char *path) {
auto wpath = u8string_to_wstring(path);
if (wpath.empty()) { return false; }
hFile_ = ::CreateFile2(wpath.c_str(), GENERIC_READ, FILE_SHARE_READ,
OPEN_EXISTING, NULL);
hFile_ =
::CreateFile2(wpath.c_str(), GENERIC_READ,
FILE_SHARE_READ | FILE_SHARE_WRITE, OPEN_EXISTING, NULL);
if (hFile_ == INVALID_HANDLE_VALUE) { return false; }