First batch of cros-disk changes

disk-manager.h

Index: disk-manager.h
diff --git a/disk-manager.h b/disk-manager.h
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+// Copyright (c) 2011 The Chromium OS Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#ifndef DISK_MANAGER_H__
+#define DISK_MANAGER_H__
+
+#include <libudev.h>
+#include <vector>
+
+namespace cros_disks {
+
+class Disk;
+
+// The DiskManager is responsible for reading device state from udev. 
+// Said changes could be the result of a udev notification or a synchronous 
+// call to enumerate the relevant storage devices attached to the system. 
+//
+// Sample Usage:
+//
+// DiskManager manager;
+// manager.EnumerateDisks();
+// select(manager.udev_monitor_fd())...
+//
+// This class is designed to run within a single-threaded GMainLoop application
+// and should not be considered thread safe.
+class DiskManager {
+ public:
+  DiskManager();
+  virtual ~DiskManager();
+
+  // Lists the current block devices attached to the system.
+  virtual std::vector<Disk> EnumerateDisks();
+
+  // Reads the changes from udev. Must be called to clear the 
+  // fd.
+  bool ProcessUdevChanges();
+
+  // A file descriptor that can be select()ed or poll()ed for system changes.
+  int udev_monitor_fd() const { return udev_monitor_fd_; }
+
+ private:
+
+  // The root udev object.
+  struct udev* udev_;
+
+  // Provides access to udev changes as they occur.
+  struct udev_monitor* udev_monitor_;
+
+  // A file descriptor that indicates changes to the system.
+  int udev_monitor_fd_;
+};
+
+} // namespace cros_disks
+
+#endif // DISK_MANAGER_H__