gecko/hal/Hal.h

/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
/* vim: set sw=2 ts=8 et ft=cpp : */
/* ***** BEGIN LICENSE BLOCK *****
 * Version: MPL 1.1/GPL 2.0/LGPL 2.1
 *
 * The contents of this file are subject to the Mozilla Public License Version
 * 1.1 (the "License"); you may not use this file except in compliance with
 * the License. You may obtain a copy of the License at:
 * http://www.mozilla.org/MPL/
 *
 * Software distributed under the License is distributed on an "AS IS" basis,
 * WITHOUT WARRANTY OF ANY KIND, either express or implied. See the License
 * for the specific language governing rights and limitations under the
 * License.
 *
 * The Original Code is Mozilla Code.
 *
 * The Initial Developer of the Original Code is
 *   The Mozilla Foundation
 * Portions created by the Initial Developer are Copyright (C) 2011
 * the Initial Developer. All Rights Reserved.
 *
 * Contributor(s):
 *   Chris Jones <jones.chris.g@gmail.com>
 *
 * Alternatively, the contents of this file may be used under the terms of
 * either the GNU General Public License Version 2 or later (the "GPL"), or
 * the GNU Lesser General Public License Version 2.1 or later (the "LGPL"),
 * in which case the provisions of the GPL or the LGPL are applicable instead
 * of those above. If you wish to allow use of your version of this file only
 * under the terms of either the GPL or the LGPL, and not to allow others to
 * use your version of this file under the terms of the MPL, indicate your
 * decision by deleting the provisions above and replace them with the notice
 * and other provisions required by the GPL or the LGPL. If you do not delete
 * the provisions above, a recipient may use your version of this file under
 * the terms of any one of the MPL, the GPL or the LGPL.
 *
 * ***** END LICENSE BLOCK ***** */

#ifndef mozilla_Hal_h
#define mozilla_Hal_h 1

#include "base/basictypes.h"
#include "mozilla/Types.h"
#include "nsTArray.h"
#include "nsCOMPtr.h"
#include "nsIDOMWindow.h"
#include "prlog.h"
#include "mozilla/dom/battery/Types.h"

#ifndef MOZ_HAL_NAMESPACE

namespace mozilla {
namespace dom {
class TabChild;
class PBrowserChild;
}
}

// Only include this hunk of code once, and include it before
// HalImpl.h and HalSandbox.h.
namespace mozilla {
namespace hal {

extern PRLogModuleInfo *sHalLog;
#define HAL_LOG(msg) PR_LOG(sHalLog, PR_LOG_DEBUG, msg)

/**
 * This class serves two purposes.
 *
 * First, this class wraps a pointer to a window.
 *
 * Second, WindowIdentifier lets us uniquely identify a window across
 * processes.  A window exposes an ID which is unique only within its
 * process.  Thus to identify a window, we need to know the ID of the
 * process which contains it.  But the scope of a process's ID is its
 * parent; that is, two processes with different parents might have
 * the same ID.
 *
 * So to identify a window, we need its ID plus the IDs of all the
 * processes in the path from the window's process to the root
 * process.  We throw in the IDs of the intermediate windows (a
 * content window is contained in a window at each level of the
 * process tree) for good measures.
 *
 * You can access this list of IDs by calling AsArray().
 */
class WindowIdentifier
{
public:
  /**
   * Create an empty WindowIdentifier.  Calls to any of this object's
   * public methods will assert -- an empty WindowIdentifier may be
   * used only as a placeholder to code which promises not to touch
   * the object.
   */
  WindowIdentifier();

  /**
   * Copy constructor.
   */
  WindowIdentifier(const WindowIdentifier& other);

  /**
   * Wrap the given window in a WindowIdentifier.  These two
   * constructors automatically grab the window's ID and append it to
   * the array of IDs.
   *
   * Note that these constructors allow an implicit conversion to a
   * WindowIdentifier.
   */
  WindowIdentifier(nsIDOMWindow* window);
  WindowIdentifier(nsCOMPtr<nsIDOMWindow> &window);

  /**
   * Create a new WindowIdentifier with the given id array and window.
   * This automatically grabs the window's ID and appends it to the
   * array.
   */
  WindowIdentifier(const nsTArray<uint64>& id, nsIDOMWindow* window);

  /**
   * Get the list of window and process IDs we contain.
   */
  typedef InfallibleTArray<uint64> IDArrayType;
  const IDArrayType& AsArray() const;

  /**
   * Append the ID of the ContentChild singleton to our array of
   * window/process IDs.
   */
  void AppendProcessID();

  /**
   * Does this WindowIdentifier identify both a window and the process
   * containing that window?  If so, we say it has traveled through
   * IPC.
   */
  bool HasTraveledThroughIPC() const;

  /**
   * Get the window this object wraps.
   */
  nsIDOMWindow* GetWindow() const;

private:
  /**
   * Get the ID of the window object we wrap.
   */
  uint64 GetWindowID() const;

  AutoInfallibleTArray<uint64, 3> mID;
  nsCOMPtr<nsIDOMWindow> mWindow;
  bool mIsEmpty;
};

} // namespace hal
} // namespace mozilla

// This goop plays some cpp tricks to ensure a uniform API across the
// API entry point, "sandbox" implementations (for content processes),
// and "impl" backends where the real work happens.  After this runs
// through cpp, there will be three sets of identical APIs
//   hal_impl:: --- the platform-specific implementation of an API.
//   hal_sandbox:: --- forwards calls up to the parent process
//   hal:: --- invokes sandboxed impl if in a sandboxed process,
//             otherwise forwards to hal_impl
//
// External code should never invoke hal_impl:: or hal_sandbox:: code
// directly.
# include "HalImpl.h"
# include "HalSandbox.h"
# define MOZ_HAL_NAMESPACE hal
# define MOZ_DEFINED_HAL_NAMESPACE 1
#endif

namespace mozilla {

namespace hal {
class BatteryInformation;
} // namespace hal

namespace MOZ_HAL_NAMESPACE /*hal*/ {

/**
 * Turn the default vibrator device on/off per the pattern specified
 * by |pattern|.  Each element in the pattern is the number of
 * milliseconds to turn the vibrator on or off.  The first element in
 * |pattern| is an "on" element, the next is "off", and so on.
 *
 * If |pattern| is empty, any in-progress vibration is canceled.
 *
 * Only an active window within an active tab may call Vibrate; calls
 * from inactive windows and windows on inactive tabs do nothing.
 *
 * If you're calling hal::Vibrate from the outside world, pass an
 * nsIDOMWindow* or an nsCOMPtr<nsIDOMWindow>& in place of the
 * WindowIdentifier parameter.  It'll be converted to a WindowIdentifier
 * automatically.
 */
void Vibrate(const nsTArray<uint32>& pattern,
             const hal::WindowIdentifier &id);

/**
 * Cancel a vibration started by the content window identified by
 * WindowIdentifier.
 *
 * If the window was the last window to start a vibration, the
 * cancellation request will go through even if the window is not
 * active.
 *
 * As with hal::Vibrate(), if you're calling hal::CancelVibrate from
 * the outside world, pass an nsIDOMWindow* or an
 * nsCOMPtr<nsIDOMWindow>&.  This will automatically be converted to a
 * WindowIdentifier object.
 */
void CancelVibrate(const hal::WindowIdentifier &id);

/**
 * Inform the battery backend there is a new battery observer.
 * @param aBatteryObserver The observer that should be added.
 */
void RegisterBatteryObserver(BatteryObserver* aBatteryObserver);

/**
 * Inform the battery backend a battery observer unregistered.
 * @param aBatteryObserver The observer that should be removed.
 */
void UnregisterBatteryObserver(BatteryObserver* aBatteryObserver);

/**
 * Enables battery notifications from the backend.
 *
 * This method is semi-private in the sense of it is visible in the hal
 * namespace but should not be used. Calls to this method from the hal
 * namespace will produce a link error because it is not defined.
 */
void EnableBatteryNotifications();

/**
 * Disables battery notifications from the backend.
 *
 * This method is semi-private in the sense of it is visible in the hal
 * namespace but should not be used. Calls to this method from the hal
 * namespace will produce a link error because it is not defined.
 */
void DisableBatteryNotifications();

/**
 * Returns the current battery information.
 */
void GetCurrentBatteryInformation(hal::BatteryInformation* aBatteryInfo);

/**
 * Notify of a change in the battery state.
 * @param aBatteryInfo The new battery information.
 */
void NotifyBatteryChange(const hal::BatteryInformation& aBatteryInfo);

/**
 * Determine whether the device's screen is currently enabled.
 */
bool GetScreenEnabled();

/**
 * Enable or disable the device's screen.
 *
 * Note that it may take a few seconds for the screen to turn on or off.
 */
void SetScreenEnabled(bool enabled);

/**
 * Get the brightness of the device's screen's backlight, on a scale from 0
 * (very dim) to 1 (full blast).
 *
 * If the display is currently disabled, this returns the brightness the
 * backlight will have when the display is re-enabled.
 */
double GetScreenBrightness();

/**
 * Set the brightness of the device's screen's backlight, on a scale from 0
 * (very dimm) to 1 (full blast).  Values larger than 1 are treated like 1, and
 * values smaller than 0 are treated like 0.
 *
 * Note that we may reduce the resolution of the given brightness value before
 * sending it to the screen.  Therefore if you call SetScreenBrightness(x)
 * followed by GetScreenBrightness(), the value returned by
 * GetScreenBrightness() may not be exactly x.
 */
void SetScreenBrightness(double brightness);

} // namespace MOZ_HAL_NAMESPACE
} // namespace mozilla

#ifdef MOZ_DEFINED_HAL_NAMESPACE
# undef MOZ_DEFINED_HAL_NAMESPACE
# undef MOZ_HAL_NAMESPACE
#endif

#endif  // mozilla_Hal_h