diff -r 000000000000 -r 6474c204b198 xpcom/build/FileLocation.h
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/xpcom/build/FileLocation.h	Wed Dec 31 06:09:35 2014 +0100
@@ -0,0 +1,141 @@
+/* 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_FileLocation_h
+#define mozilla_FileLocation_h
+
+#include "nsString.h"
+#include "nsCOMPtr.h"
+#include "nsAutoPtr.h"
+#include "nsIFile.h"
+#include "FileUtils.h"
+
+class nsZipArchive;
+class nsZipItem;
+
+namespace mozilla {
+
+class FileLocation
+{
+public:
+  /**
+   * FileLocation is an helper to handle different kind of file locations
+   * within Gecko:
+   * - on filesystems
+   * - in archives
+   * - in archives within archives
+   * As such, it stores a path within an archive, as well as the archive
+   * path itself, or the complete file path alone when on a filesystem.
+   * When the archive is in an archive, an nsZipArchive is stored instead
+   * of a file path.
+   */
+  FileLocation();
+  ~FileLocation();
+
+  /**
+   * Constructor for plain files
+   */
+  FileLocation(nsIFile *file);
+
+  /**
+   * Constructors for path within an archive. The archive can be given either
+   * as nsIFile or nsZipArchive.
+   */
+  FileLocation(nsIFile *zip, const char *path);
+
+  FileLocation(nsZipArchive *zip, const char *path);
+
+  /**
+   * Creates a new file location relative to another one.
+   */
+  FileLocation(const FileLocation &file, const char *path = nullptr);
+
+  /**
+   * Initialization functions corresponding to constructors
+   */
+  void Init(nsIFile *file);
+
+  void Init(nsIFile *zip, const char *path);
+
+  void Init(nsZipArchive *zip, const char *path);
+
+  /**
+   * Returns an URI string corresponding to the file location
+   */
+  void GetURIString(nsACString &result) const;
+
+  /**
+   * Returns the base file of the location, where base file is defined as:
+   * - The file itself when the location is on a filesystem
+   * - The archive file when the location is in an archive
+   * - The outer archive file when the location is in an archive in an archive
+   */
+  already_AddRefed<nsIFile> GetBaseFile();
+
+  /**
+   * Returns whether the "base file" (see GetBaseFile) is an archive
+   */
+  bool IsZip() const
+  {
+    return !mPath.IsEmpty();
+  }
+
+  /**
+   * Returns the path within the archive, when within an archive
+   */
+  void GetPath(nsACString &result) const
+  {
+    result = mPath;
+  }
+
+  /**
+   * Boolean value corresponding to whether the file location is initialized
+   * or not.
+   */
+  operator bool() const
+  {
+    return mBaseFile || mBaseZip;
+  }
+
+  /**
+   * Returns whether another FileLocation points to the same resource
+   */
+  bool Equals(const FileLocation &file) const;
+
+  /**
+   * Data associated with a FileLocation.
+   */
+  class Data
+  {
+  public:
+    /**
+     * Returns the data size
+     */
+    nsresult GetSize(uint32_t *result);
+
+    /**
+     * Copies the data in the given buffer
+     */
+    nsresult Copy(char *buf, uint32_t len);
+  protected:
+    friend class FileLocation;
+    nsZipItem *mItem;
+    nsRefPtr<nsZipArchive> mZip;
+    mozilla::AutoFDClose mFd;
+  };
+
+  /**
+   * Returns the data associated with the resource pointed at by the file
+   * location.
+   */
+  nsresult GetData(Data &data);
+private:
+  nsCOMPtr<nsIFile> mBaseFile;
+  nsRefPtr<nsZipArchive> mBaseZip;
+  nsCString mPath;
+}; /* class FileLocation */
+
+} /* namespace mozilla */
+
+#endif /* mozilla_FileLocation_h */