1 files changed, 48 insertions, 0 deletions
diff --git a/xpcom/io/FileDescriptorFile.h b/xpcom/io/FileDescriptorFile.h
new file mode 100644
index 0000000000..1d0fbad2d8
--- /dev/null
+++ b/xpcom/io/FileDescriptorFile.h
@@ -0,0 +1,48 @@
+/* -*- 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 _FileDescriptorFile_h
+#define _FileDescriptorFile_h
+
+#include "mozilla/Attributes.h"
+#include "mozilla/ipc/FileDescriptor.h"
+#include "nsIFile.h"
+#include "private/pprio.h"
+
+namespace mozilla {
+namespace net {
+
+/**
+ * A limited implementation of nsIFile that wraps a FileDescriptor object
+ * allowing the file to be read from. Added to allow a child process to use
+ * an nsIFile object for a file it does not have access to on the filesystem
+ * but has been provided a FileDescriptor for from the parent. Many nsIFile
+ * methods are not implemented and this is not intended to be a general
+ * purpose file implementation.
+ */
+class FileDescriptorFile final : public nsIFile {
+  typedef mozilla::ipc::FileDescriptor FileDescriptor;
+
+ public:
+  FileDescriptorFile(const FileDescriptor& aFD, nsIFile* aFile);
+
+  NS_DECL_THREADSAFE_ISUPPORTS
+  NS_DECL_NSIFILE
+
+ private:
+  ~FileDescriptorFile() = default;
+
+  FileDescriptorFile(const FileDescriptorFile& other);
+
+  // regular nsIFile object, that we forward most calls to.
+  nsCOMPtr<nsIFile> mFile;
+  FileDescriptor mFD;
+};
+
+}  // namespace net
+}  // namespace mozilla
+
+#endif  // _FileDescriptorFile_h