import FIREFOX_52_6_0esr_RELEASE from mozilla-esr52 hg repo

ipc/glue/FileDescriptorUtils.h

@@ -0,0 +1,61 @@
+/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* vim: set ts=8 sts=2 et sw=2 tw=80: */
+/* 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/. */
+
+#ifndef mozilla_ipc_FileDescriptorUtils_h
+#define mozilla_ipc_FileDescriptorUtils_h
+
+#include "mozilla/Attributes.h"
+#include "mozilla/ipc/FileDescriptor.h"
+#include "nsIRunnable.h"
+#include <stdio.h>
+
+namespace mozilla {
+namespace ipc {
+
+// When Dispatch() is called (from main thread) this class arranges to close the
+// provided FileDescriptor on one of the socket transport service threads (to
+// avoid main thread I/O).
+class CloseFileRunnable final : public nsIRunnable
+{
+  typedef mozilla::ipc::FileDescriptor FileDescriptor;
+
+  FileDescriptor mFileDescriptor;
+
+public:
+  explicit CloseFileRunnable(const FileDescriptor& aFileDescriptor)
+#ifdef DEBUG
+  ;
+#else
+  : mFileDescriptor(aFileDescriptor)
+  { }
+#endif
+
+  NS_DECL_THREADSAFE_ISUPPORTS
+  NS_DECL_NSIRUNNABLE
+
+  void Dispatch();
+
+private:
+  ~CloseFileRunnable();
+
+  void CloseFile();
+};
+
+// On failure, FileDescriptorToFILE returns nullptr; on success,
+// returns duplicated FILE*.
+// This is meant for use with FileDescriptors received over IPC.
+FILE* FileDescriptorToFILE(const FileDescriptor& aDesc,
+                           const char* aOpenMode);
+
+// FILEToFileDescriptor does not consume the given FILE*; it must be
+// fclose()d as normal, and this does not invalidate the returned
+// FileDescriptor.
+FileDescriptor FILEToFileDescriptor(FILE* aStream);
+
+} // namespace ipc
+} // namespace mozilla
+
+#endif // mozilla_ipc_FileDescriptorUtils_h