Hal.cpp

/* -*- 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 ***** */

#include "Hal.h"
#include "HalImpl.h"
#include "HalSandbox.h"
#include "mozilla/Util.h"
#include "nsThreadUtils.h"
#include "nsXULAppAPI.h"
#include "mozilla/Observer.h"
#include "nsIDOMDocument.h"
#include "nsIDOMWindow.h"
#include "mozilla/Services.h"
#include "nsIWebNavigation.h"
#include "nsITabChild.h"
#include "nsIDocShell.h"
#include "mozilla/ClearOnShutdown.h"
#include "WindowIdentifier.h"

using namespace mozilla::services;

#define PROXY_IF_SANDBOXED(_call)                 \
  do {                                            \
    if (InSandbox()) {                            \
      hal_sandbox::_call;                         \
    } else {                                      \
      hal_impl::_call;                            \
    }                                             \
  } while (0)

#define RETURN_PROXY_IF_SANDBOXED(_call)          \
  do {                                            \
    if (InSandbox()) {                            \
      return hal_sandbox::_call;                  \
    } else {                                      \
      return hal_impl::_call;                     \
    }                                             \
  } while (0)

namespace mozilla {
namespace hal {

PRLogModuleInfo *sHalLog = PR_LOG_DEFINE("hal");

namespace {

void
AssertMainThread()
{
  MOZ_ASSERT(NS_IsMainThread());
}

bool
InSandbox()
{
  return GeckoProcessType_Content == XRE_GetProcessType();
}

bool
WindowIsActive(nsIDOMWindow *window)
{
  NS_ENSURE_TRUE(window, false);

  nsCOMPtr<nsIDOMDocument> doc;
  window->GetDocument(getter_AddRefs(doc));
  NS_ENSURE_TRUE(doc, false);

  bool hidden = true;
  doc->GetMozHidden(&hidden);
  return !hidden;
}

nsAutoPtr<WindowIdentifier::IDArrayType> gLastIDToVibrate;

void InitLastIDToVibrate()
{
  gLastIDToVibrate = new WindowIdentifier::IDArrayType();
  ClearOnShutdown(&gLastIDToVibrate);
}

} // anonymous namespace

void
Vibrate(const nsTArray<uint32>& pattern, nsIDOMWindow* window)
{
  Vibrate(pattern, WindowIdentifier(window));
}

void
Vibrate(const nsTArray<uint32>& pattern, const WindowIdentifier &id)
{
  AssertMainThread();

  // Only active windows may start vibrations.  If |id| hasn't gone
  // through the IPC layer -- that is, if our caller is the outside
  // world, not hal_proxy -- check whether the window is active.  If
  // |id| has gone through IPC, don't check the window's visibility;
  // only the window corresponding to the bottommost process has its
  // visibility state set correctly.
  if (!id.HasTraveledThroughIPC() && !WindowIsActive(id.GetWindow())) {
    HAL_LOG(("Vibrate: Window is inactive, dropping vibrate."));
    return;
  }

  if (InSandbox()) {
    hal_sandbox::Vibrate(pattern, id);
  }
  else {
    if (!gLastIDToVibrate)
      InitLastIDToVibrate();
    *gLastIDToVibrate = id.AsArray();

    HAL_LOG(("Vibrate: Forwarding to hal_impl."));

    // hal_impl doesn't need |id|. Send it an empty id, which will
    // assert if it's used.
    hal_impl::Vibrate(pattern, WindowIdentifier());
  }
}

void
CancelVibrate(nsIDOMWindow* window)
{
  CancelVibrate(WindowIdentifier(window));
}

void
CancelVibrate(const WindowIdentifier &id)
{
  AssertMainThread();

  // Although only active windows may start vibrations, a window may
  // cancel its own vibration even if it's no longer active.
  //
  // After a window is marked as inactive, it sends a CancelVibrate
  // request.  We want this request to cancel a playing vibration
  // started by that window, so we certainly don't want to reject the
  // cancellation request because the window is now inactive.
  //
  // But it could be the case that, after this window became inactive,
  // some other window came along and started a vibration.  We don't
  // want this window's cancellation request to cancel that window's
  // actively-playing vibration!
  //
  // To solve this problem, we keep track of the id of the last window
  // to start a vibration, and only accepts cancellation requests from
  // the same window.  All other cancellation requests are ignored.

  if (InSandbox()) {
    hal_sandbox::CancelVibrate(id);
  }
  else if (*gLastIDToVibrate == id.AsArray()) {
    // Don't forward our ID to hal_impl. It doesn't need it, and we
    // don't want it to be tempted to read it.  The empty identifier
    // will assert if it's used.
    HAL_LOG(("CancelVibrate: Forwarding to hal_impl."));
    hal_impl::CancelVibrate(WindowIdentifier());
  }
}

template <class InfoType>
class ObserversManager
{
public:
  void AddObserver(Observer<InfoType>* aObserver) {
    if (!mObservers) {
      mObservers = new ObserverList<InfoType>();
    }

    mObservers->AddObserver(aObserver);

    if (mObservers->Length() == 1) {
      EnableNotifications();
    }
  }

  void RemoveObserver(Observer<InfoType>* aObserver) {
    MOZ_ASSERT(mObservers);
    mObservers->RemoveObserver(aObserver);

    if (mObservers->Length() == 0) {
      DisableNotifications();

      delete mObservers;
      mObservers = 0;

      mHasValidCache = false;
    }
  }

  InfoType GetCurrentInformation() {
    if (mHasValidCache) {
      return mInfo;
    }

    mHasValidCache = true;
    GetCurrentInformationInternal(&mInfo);
    return mInfo;
  }

  void CacheInformation(const InfoType& aInfo) {
    mHasValidCache = true;
    mInfo = aInfo;
  }

  void BroadcastCachedInformation() {
    MOZ_ASSERT(mObservers);
    mObservers->Broadcast(mInfo);
  }

protected:
  virtual void EnableNotifications() = 0;
  virtual void DisableNotifications() = 0;
  virtual void GetCurrentInformationInternal(InfoType*) = 0;

private:
  ObserverList<InfoType>* mObservers;
  InfoType                mInfo;
  bool                    mHasValidCache;
};

class BatteryObserversManager : public ObserversManager<BatteryInformation>
{
protected:
  void EnableNotifications() {
    PROXY_IF_SANDBOXED(EnableBatteryNotifications());
  }

  void DisableNotifications() {
    PROXY_IF_SANDBOXED(DisableBatteryNotifications());
  }

  void GetCurrentInformationInternal(BatteryInformation* aInfo) {
    PROXY_IF_SANDBOXED(GetCurrentBatteryInformation(aInfo));
  }
};

static BatteryObserversManager sBatteryObservers;

void
RegisterBatteryObserver(BatteryObserver* aObserver)
{
  AssertMainThread();
  sBatteryObservers.AddObserver(aObserver);
}

void
UnregisterBatteryObserver(BatteryObserver* aObserver)
{
  AssertMainThread();
  sBatteryObservers.RemoveObserver(aObserver);
}

void
GetCurrentBatteryInformation(BatteryInformation* aInfo)
{
  AssertMainThread();
  *aInfo = sBatteryObservers.GetCurrentInformation();
}

void
NotifyBatteryChange(const BatteryInformation& aInfo)
{
  AssertMainThread();
  sBatteryObservers.CacheInformation(aInfo);
  sBatteryObservers.BroadcastCachedInformation();
}

bool GetScreenEnabled()
{
  AssertMainThread();
  RETURN_PROXY_IF_SANDBOXED(GetScreenEnabled());
}

void SetScreenEnabled(bool enabled)
{
  AssertMainThread();
  PROXY_IF_SANDBOXED(SetScreenEnabled(enabled));
}

double GetScreenBrightness()
{
  AssertMainThread();
  RETURN_PROXY_IF_SANDBOXED(GetScreenBrightness());
}

void SetScreenBrightness(double brightness)
{
  AssertMainThread();
  PROXY_IF_SANDBOXED(SetScreenBrightness(clamped(brightness, 0.0, 1.0)));
}

} // namespace hal
} // namespace mozilla