diff -r 000000000000 -r 6474c204b198 ipc/glue/FileDescriptor.cpp
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/ipc/glue/FileDescriptor.cpp	Wed Dec 31 06:09:35 2014 +0100
@@ -0,0 +1,121 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include "FileDescriptor.h"
+
+#include "mozilla/Assertions.h"
+#include "nsDebug.h"
+
+#ifdef XP_WIN
+
+#include <windows.h>
+#define INVALID_HANDLE INVALID_HANDLE_VALUE
+
+#else // XP_WIN
+
+#include <unistd.h>
+
+#ifndef OS_POSIX
+#define OS_POSIX
+#endif
+
+#include "base/eintr_wrapper.h"
+#define INVALID_HANDLE -1
+
+#endif // XP_WIN
+
+using mozilla::ipc::FileDescriptor;
+
+FileDescriptor::FileDescriptor()
+: mHandle(INVALID_HANDLE), mHandleCreatedByOtherProcess(false),
+  mHandleCreatedByOtherProcessWasUsed(false)
+{ }
+
+FileDescriptor::FileDescriptor(PlatformHandleType aHandle)
+: mHandle(INVALID_HANDLE), mHandleCreatedByOtherProcess(false),
+  mHandleCreatedByOtherProcessWasUsed(false)
+{
+  DuplicateInCurrentProcess(aHandle);
+}
+
+void
+FileDescriptor::DuplicateInCurrentProcess(PlatformHandleType aHandle)
+{
+  MOZ_ASSERT_IF(mHandleCreatedByOtherProcess,
+                mHandleCreatedByOtherProcessWasUsed);
+
+  if (IsValid(aHandle)) {
+    PlatformHandleType newHandle;
+#ifdef XP_WIN
+    if (DuplicateHandle(GetCurrentProcess(), aHandle, GetCurrentProcess(),
+                        &newHandle, 0, FALSE, DUPLICATE_SAME_ACCESS)) {
+#else // XP_WIN
+    if ((newHandle = dup(aHandle)) != INVALID_HANDLE) {
+#endif
+      mHandle = newHandle;
+      return;
+    }
+    NS_WARNING("Failed to duplicate file handle for current process!");
+  }
+
+  mHandle = INVALID_HANDLE;
+}
+
+void
+FileDescriptor::CloseCurrentProcessHandle()
+{
+  MOZ_ASSERT_IF(mHandleCreatedByOtherProcess,
+                mHandleCreatedByOtherProcessWasUsed);
+
+  // Don't actually close handles created by another process.
+  if (mHandleCreatedByOtherProcess) {
+    return;
+  }
+
+  if (IsValid()) {
+#ifdef XP_WIN
+    if (!CloseHandle(mHandle)) {
+      NS_WARNING("Failed to close file handle for current process!");
+    }
+#else // XP_WIN
+    HANDLE_EINTR(close(mHandle));
+#endif
+    mHandle = INVALID_HANDLE;
+  }
+}
+
+FileDescriptor::PickleType
+FileDescriptor::ShareTo(const FileDescriptor::IPDLPrivate&,
+                        FileDescriptor::ProcessHandle aOtherProcess) const
+{
+  PlatformHandleType newHandle;
+#ifdef XP_WIN
+  if (IsValid()) {
+    if (DuplicateHandle(GetCurrentProcess(), mHandle, aOtherProcess,
+                        &newHandle, 0, FALSE, DUPLICATE_SAME_ACCESS)) {
+      return newHandle;
+    }
+    NS_WARNING("Failed to duplicate file handle for other process!");
+  }
+  return INVALID_HANDLE;
+#else // XP_WIN
+  if (IsValid()) {
+    newHandle = dup(mHandle);
+    if (IsValid(newHandle)) {
+      return base::FileDescriptor(newHandle, /* auto_close */ true);
+    }
+    NS_WARNING("Failed to duplicate file handle for other process!");
+  }
+  return base::FileDescriptor();
+#endif
+
+  MOZ_CRASH("Must not get here!");
+}
+
+// static
+bool
+FileDescriptor::IsValid(PlatformHandleType aHandle)
+{
+  return aHandle != INVALID_HANDLE;
+}