LibCore: Port AnonymousBuffer to Windows

Author: https://github.com/stasoid
Commit: https://github.com/LadybirdBrowser/ladybird/commit/e6749eb6b72
Pull-request: https://github.com/LadybirdBrowser/ladybird/pull/2004
Reviewed-by: https://github.com/ADKaster ✅

Userland/Libraries/LibCore/AnonymousBuffer.cpp

@@ -43,11 +43,6 @@ ErrorOr<AnonymousBuffer> AnonymousBuffer::create_from_anon_fd(int fd, size_t siz
     return AnonymousBuffer(move(impl));
 }
 
-AnonymousBuffer::AnonymousBuffer(NonnullRefPtr<AnonymousBufferImpl> impl)
-    : m_impl(move(impl))
-{
-}
-
 AnonymousBufferImpl::AnonymousBufferImpl(int fd, size_t size, void* data)
     : m_fd(fd)
     , m_size(size)

Userland/Libraries/LibCore/AnonymousBuffer.h

@@ -18,6 +18,7 @@ namespace Core {
 
 class AnonymousBufferImpl final : public RefCounted<AnonymousBufferImpl> {
 public:
+    static ErrorOr<NonnullRefPtr<AnonymousBufferImpl>> create(size_t);
     static ErrorOr<NonnullRefPtr<AnonymousBufferImpl>> create(int fd, size_t);
     ~AnonymousBufferImpl();
 
@@ -65,7 +66,10 @@ public:
     }
 
 private:
-    explicit AnonymousBuffer(NonnullRefPtr<AnonymousBufferImpl>);
+    explicit AnonymousBuffer(NonnullRefPtr<AnonymousBufferImpl> impl)
+        : m_impl(move(impl))
+    {
+    }
 
     RefPtr<AnonymousBufferImpl> m_impl;
 };

Userland/Libraries/LibCore/AnonymousBufferWindows.cpp

@@ -0,0 +1,59 @@
+/*
+ * Copyright (c) 2021, Andreas Kling <andreas@ladybird.org>
+ * Copyright (c) 2024, stasoid <stasoid@yahoo.com>
+ *
+ * SPDX-License-Identifier: BSD-2-Clause
+ */
+
+#include <LibCore/AnonymousBuffer.h>
+#include <windows.h>
+
+namespace Core {
+
+AnonymousBufferImpl::AnonymousBufferImpl(int fd, size_t size, void* data)
+    : m_fd(fd)
+    , m_size(size)
+    , m_data(data)
+{
+}
+
+AnonymousBufferImpl::~AnonymousBufferImpl()
+{
+    if (m_data)
+        VERIFY(UnmapViewOfFile(m_data));
+
+    if (m_fd != -1)
+        VERIFY(CloseHandle((HANDLE)(intptr_t)m_fd));
+}
+
+ErrorOr<NonnullRefPtr<AnonymousBufferImpl>> AnonymousBufferImpl::create(size_t size)
+{
+    HANDLE map_handle = CreateFileMapping(INVALID_HANDLE_VALUE, NULL, PAGE_READWRITE, HIWORD(size), LOWORD(size), NULL);
+    if (!map_handle)
+        return Error::from_windows_error(GetLastError());
+
+    return create((int)(intptr_t)map_handle, size);
+}
+
+ErrorOr<NonnullRefPtr<AnonymousBufferImpl>> AnonymousBufferImpl::create(int fd, size_t size)
+{
+    void* ptr = MapViewOfFile((HANDLE)(intptr_t)fd, FILE_MAP_ALL_ACCESS, 0, 0, size);
+    if (!ptr)
+        return Error::from_windows_error(GetLastError());
+
+    return adopt_nonnull_ref_or_enomem(new (nothrow) AnonymousBufferImpl(fd, size, ptr));
+}
+
+ErrorOr<AnonymousBuffer> AnonymousBuffer::create_with_size(size_t size)
+{
+    auto impl = TRY(AnonymousBufferImpl::create(size));
+    return AnonymousBuffer(move(impl));
+}
+
+ErrorOr<AnonymousBuffer> AnonymousBuffer::create_from_anon_fd(int fd, size_t size)
+{
+    auto impl = TRY(AnonymousBufferImpl::create(fd, size));
+    return AnonymousBuffer(move(impl));
+}
+
+}

Userland/Libraries/LibCore/CMakeLists.txt

@@ -29,7 +29,6 @@ if (LAGOM_TOOLS_ONLY)
 endif()
 
 set(SOURCES
-    AnonymousBuffer.cpp
     Command.cpp
     ConfigFile.cpp
     DateTime.cpp
@@ -54,6 +53,13 @@ set(SOURCES
     Timer.cpp
     UDPServer.cpp
 )
+
+if (WIN32)
+    list(APPEND SOURCES AnonymousBufferWindows.cpp)
+else()
+    list(APPEND SOURCES AnonymousBuffer.cpp)
+endif()
+
 if (NOT WIN32 AND NOT EMSCRIPTEN)
     list(APPEND SOURCES LocalServer.cpp)
 endif()