TaskbarPreview.cpp

/* vim: se cin sw=2 ts=2 et : */
/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*-
 *
 * 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/. */

#include "TaskbarPreview.h"
#include <nsITaskbarPreviewController.h>
#include <windows.h>

#include <nsError.h>
#include <nsCOMPtr.h>
#include <nsIWidget.h>
#include <nsIBaseWindow.h>
#include <nsIObserverService.h>
#include <nsServiceManagerUtils.h>

#include "nsUXThemeData.h"
#include "nsWindow.h"
#include "nsAppShell.h"
#include "TaskbarPreviewButton.h"
#include "WinUtils.h"

#include "mozilla/dom/HTMLCanvasElement.h"
#include "mozilla/gfx/2D.h"
#include "mozilla/gfx/DataSurfaceHelpers.h"
#include "mozilla/Telemetry.h"

// Defined in dwmapi in a header that needs a higher numbered _WINNT #define
#ifndef DWM_SIT_DISPLAYFRAME
#define DWM_SIT_DISPLAYFRAME 0x1
#endif

namespace mozilla {
namespace widget {

///////////////////////////////////////////////////////////////////////////////
// TaskbarPreview

TaskbarPreview::TaskbarPreview(ITaskbarList4 *aTaskbar, nsITaskbarPreviewController *aController, HWND aHWND, nsIDocShell *aShell)
  : mTaskbar(aTaskbar),
    mController(aController),
    mWnd(aHWND),
    mVisible(false),
    mDocShell(do_GetWeakReference(aShell))
{
  // TaskbarPreview may outlive the WinTaskbar that created it
  ::CoInitialize(nullptr);

  WindowHook &hook = GetWindowHook();
  hook.AddMonitor(WM_DESTROY, MainWindowHook, this);
}

TaskbarPreview::~TaskbarPreview() {
  // Avoid dangling pointer
  if (sActivePreview == this)
    sActivePreview = nullptr;

  // Our subclass should have invoked DetachFromNSWindow already.
  NS_ASSERTION(!mWnd, "TaskbarPreview::DetachFromNSWindow was not called before destruction");

  // Make sure to release before potentially uninitializing COM
  mTaskbar = nullptr;

  ::CoUninitialize();
}

NS_IMETHODIMP
TaskbarPreview::SetController(nsITaskbarPreviewController *aController) {
  NS_ENSURE_ARG(aController);

  mController = aController;
  return NS_OK;
}

NS_IMETHODIMP
TaskbarPreview::GetController(nsITaskbarPreviewController **aController) {
  NS_ADDREF(*aController = mController);
  return NS_OK;
}

NS_IMETHODIMP
TaskbarPreview::GetTooltip(nsAString &aTooltip) {
  aTooltip = mTooltip;
  return NS_OK;
}

NS_IMETHODIMP
TaskbarPreview::SetTooltip(const nsAString &aTooltip) {
  mTooltip = aTooltip;
  return CanMakeTaskbarCalls() ? UpdateTooltip() : NS_OK;
}

NS_IMETHODIMP
TaskbarPreview::SetVisible(bool visible) {
  if (mVisible == visible) return NS_OK;
  mVisible = visible;

  // If the nsWindow has already been destroyed but the caller is still trying
  // to use it then just pretend that everything succeeded.  The caller doesn't
  // actually have a way to detect this since it's the same case as when we
  // CanMakeTaskbarCalls returns false.
  if (!mWnd)
    return NS_OK;

  return visible ? Enable() : Disable();
}

NS_IMETHODIMP
TaskbarPreview::GetVisible(bool *visible) {
  *visible = mVisible;
  return NS_OK;
}

NS_IMETHODIMP
TaskbarPreview::SetActive(bool active) {
  if (active)
    sActivePreview = this;
  else if (sActivePreview == this)
    sActivePreview = nullptr;

  return CanMakeTaskbarCalls() ? ShowActive(active) : NS_OK;
}

NS_IMETHODIMP
TaskbarPreview::GetActive(bool *active) {
  *active = sActivePreview == this;
  return NS_OK;
}

NS_IMETHODIMP
TaskbarPreview::Invalidate() {
  if (!mVisible)
    return NS_OK;

  // DWM Composition is required for previews
  if (!nsUXThemeData::CheckForCompositor())
    return NS_OK;

  HWND previewWindow = PreviewWindow();
  return FAILED(DwmInvalidateIconicBitmaps(previewWindow))
       ? NS_ERROR_FAILURE
       : NS_OK;
}

nsresult
TaskbarPreview::UpdateTaskbarProperties() {
  nsresult rv = UpdateTooltip();

  // If we are the active preview and our window is the active window, restore
  // our active state - otherwise some other non-preview window is now active
  // and should be displayed as so.
  if (sActivePreview == this) {
    if (mWnd == ::GetActiveWindow()) {
      nsresult rvActive = ShowActive(true);
      if (NS_FAILED(rvActive))
        rv = rvActive;
    } else {
      sActivePreview = nullptr;
    }
  }
  return rv;
}

nsresult
TaskbarPreview::Enable() {
  nsresult rv = NS_OK;
  if (CanMakeTaskbarCalls()) {
    rv = UpdateTaskbarProperties();
  } else {
    WindowHook &hook = GetWindowHook();
    hook.AddMonitor(nsAppShell::GetTaskbarButtonCreatedMessage(), MainWindowHook, this);
  }
  return rv;
}

nsresult
TaskbarPreview::Disable() {
  if (!IsWindowAvailable()) {
    // Window is already destroyed
    return NS_OK;
  }

  WindowHook &hook = GetWindowHook();
  (void) hook.RemoveMonitor(nsAppShell::GetTaskbarButtonCreatedMessage(), MainWindowHook, this);

  return NS_OK;
}

bool
TaskbarPreview::IsWindowAvailable() const {
  if (mWnd) {
    nsWindow* win = WinUtils::GetNSWindowPtr(mWnd);
    if(win && !win->Destroyed()) {
      return true;
    }
  }
  return false;
}

void
TaskbarPreview::DetachFromNSWindow() {
  WindowHook &hook = GetWindowHook();
  hook.RemoveMonitor(WM_DESTROY, MainWindowHook, this);
  mWnd = nullptr;
}

LRESULT
TaskbarPreview::WndProc(UINT nMsg, WPARAM wParam, LPARAM lParam) {
  switch (nMsg) {
    case WM_DWMSENDICONICTHUMBNAIL:
      {
        uint32_t width = HIWORD(lParam);
        uint32_t height = LOWORD(lParam);
        float aspectRatio = width/float(height);

        nsresult rv;
        float preferredAspectRatio;
        rv = mController->GetThumbnailAspectRatio(&preferredAspectRatio);
        if (NS_FAILED(rv))
          break;

        uint32_t thumbnailWidth = width;
        uint32_t thumbnailHeight = height;

        if (aspectRatio > preferredAspectRatio) {
          thumbnailWidth = uint32_t(thumbnailHeight * preferredAspectRatio);
        } else {
          thumbnailHeight = uint32_t(thumbnailWidth / preferredAspectRatio);
        }

        DrawBitmap(thumbnailWidth, thumbnailHeight, false);
      }
      break;
    case WM_DWMSENDICONICLIVEPREVIEWBITMAP:
      {
        uint32_t width, height;
        nsresult rv;
        rv = mController->GetWidth(&width);
        if (NS_FAILED(rv))
          break;
        rv = mController->GetHeight(&height);
        if (NS_FAILED(rv))
          break;

        double scale = nsIWidget::DefaultScaleOverride();
        if (scale <= 0.0) {
          scale = WinUtils::LogToPhysFactor(PreviewWindow());
        }
        DrawBitmap(NSToIntRound(scale * width), NSToIntRound(scale * height), true);
      }
      break;
  }
  return ::DefWindowProcW(PreviewWindow(), nMsg, wParam, lParam);
}

bool
TaskbarPreview::CanMakeTaskbarCalls() {
  // If the nsWindow has already been destroyed and we know it but our caller
  // clearly doesn't so we can't make any calls.
  if (!mWnd)
    return false;
  // Certain functions like SetTabOrder seem to require a visible window. During
  // window close, the window seems to be hidden before being destroyed.
  if (!::IsWindowVisible(mWnd))
    return false;
  if (mVisible) {
    nsWindow *window = WinUtils::GetNSWindowPtr(mWnd);
    NS_ASSERTION(window, "Could not get nsWindow from HWND");
    return window->HasTaskbarIconBeenCreated();
  }
  return false;
}

WindowHook&
TaskbarPreview::GetWindowHook() {
  nsWindow *window = WinUtils::GetNSWindowPtr(mWnd);
  NS_ASSERTION(window, "Cannot use taskbar previews in an embedded context!");

  return window->GetWindowHook();
}

void
TaskbarPreview::EnableCustomDrawing(HWND aHWND, bool aEnable) {
  BOOL enabled = aEnable;
  DwmSetWindowAttribute(
      aHWND,
      DWMWA_FORCE_ICONIC_REPRESENTATION,
      &enabled,
      sizeof(enabled));

  DwmSetWindowAttribute(
      aHWND,
      DWMWA_HAS_ICONIC_BITMAP,
      &enabled,
      sizeof(enabled));
}


nsresult
TaskbarPreview::UpdateTooltip() {
  NS_ASSERTION(CanMakeTaskbarCalls() && mVisible, "UpdateTooltip called on invisible tab preview");

  if (FAILED(mTaskbar->SetThumbnailTooltip(PreviewWindow(), mTooltip.get())))
    return NS_ERROR_FAILURE;
  return NS_OK;
}

void
TaskbarPreview::DrawBitmap(uint32_t width, uint32_t height, bool isPreview) {
  nsresult rv;
  nsCOMPtr<nsITaskbarPreviewCallback> callback =
    do_CreateInstance("@mozilla.org/widget/taskbar-preview-callback;1", &rv);
  if (NS_FAILED(rv)) {
    return;
  }

  ((TaskbarPreviewCallback*)callback.get())->SetPreview(this);

  if (isPreview) {
    ((TaskbarPreviewCallback*)callback.get())->SetIsPreview();
    mController->RequestPreview(callback);
  } else {
    mController->RequestThumbnail(callback, width, height);
  }
}

///////////////////////////////////////////////////////////////////////////////
// TaskbarPreviewCallback

NS_IMPL_ISUPPORTS(TaskbarPreviewCallback, nsITaskbarPreviewCallback)

/* void done (in nsISupports aCanvas, in boolean aDrawBorder); */
NS_IMETHODIMP
TaskbarPreviewCallback::Done(nsISupports *aCanvas, bool aDrawBorder) {
  // We create and destroy TaskbarTabPreviews from front end code in response
  // to TabOpen and TabClose events. Each TaskbarTabPreview creates and owns a
  // proxy HWND which it hands to Windows as a tab identifier. When a tab
  // closes, TaskbarTabPreview Disable() method is called by front end, which
  // destroys the proxy window and clears mProxyWindow which is the HWND
  // returned from PreviewWindow(). So, since this is async, we should check to
  // be sure the tab is still alive before doing all this gfx work and making
  // dwm calls. To accomplish this we check the result of PreviewWindow().
  if (!aCanvas || !mPreview || !mPreview->PreviewWindow() ||
      !mPreview->IsWindowAvailable()) {
    return NS_ERROR_FAILURE;
  }

  nsCOMPtr<nsIDOMHTMLCanvasElement> domcanvas(do_QueryInterface(aCanvas));
  dom::HTMLCanvasElement * canvas = ((dom::HTMLCanvasElement*)domcanvas.get());
  if (!canvas) {
    return NS_ERROR_FAILURE;
  }

  RefPtr<gfx::SourceSurface> source = canvas->GetSurfaceSnapshot();
  if (!source) {
    return NS_ERROR_FAILURE;
  }
  RefPtr<gfxWindowsSurface> target = new gfxWindowsSurface(source->GetSize(),
                                                           gfx::SurfaceFormat::A8R8G8B8_UINT32);
  if (!target) {
    return NS_ERROR_FAILURE;
  }

  RefPtr<gfx::DataSourceSurface> srcSurface = source->GetDataSurface();
  RefPtr<gfxImageSurface> imageSurface = target->GetAsImageSurface();
  if (!srcSurface || !imageSurface) {
    return NS_ERROR_FAILURE;
  }

  gfx::DataSourceSurface::MappedSurface sourceMap;
  srcSurface->Map(gfx::DataSourceSurface::READ, &sourceMap);
  mozilla::gfx::CopySurfaceDataToPackedArray(sourceMap.mData,
                                             imageSurface->Data(),
                                             srcSurface->GetSize(),
                                             sourceMap.mStride,
                                             BytesPerPixel(srcSurface->GetFormat()));
  srcSurface->Unmap();

  HDC hDC = target->GetDC();
  HBITMAP hBitmap = (HBITMAP)GetCurrentObject(hDC, OBJ_BITMAP);

  DWORD flags = aDrawBorder ? DWM_SIT_DISPLAYFRAME : 0;
  POINT pptClient = { 0, 0 };
  HRESULT hr;
  if (!mIsThumbnail) {
    hr = DwmSetIconicLivePreviewBitmap(mPreview->PreviewWindow(),
                                       hBitmap, &pptClient, flags);
  } else {
    hr = DwmSetIconicThumbnail(mPreview->PreviewWindow(),
                               hBitmap, flags);
  }
  MOZ_ASSERT(SUCCEEDED(hr));
  return NS_OK;
}

/* static */
bool
TaskbarPreview::MainWindowHook(void *aContext,
                               HWND hWnd, UINT nMsg,
                               WPARAM wParam, LPARAM lParam,
                               LRESULT *aResult)
{
  NS_ASSERTION(nMsg == nsAppShell::GetTaskbarButtonCreatedMessage() ||
               nMsg == WM_DESTROY,
               "Window hook proc called with wrong message");
  NS_ASSERTION(aContext, "Null context in MainWindowHook");
  if (!aContext)
    return false;
  TaskbarPreview *preview = reinterpret_cast<TaskbarPreview*>(aContext);
  if (nMsg == WM_DESTROY) {
    // nsWindow is being destroyed
    // We can't really do anything at this point including removing hooks
    return false;
  } else {
    nsWindow *window = WinUtils::GetNSWindowPtr(preview->mWnd);
    if (window) {
      window->SetHasTaskbarIconBeenCreated();

      if (preview->mVisible)
        preview->UpdateTaskbarProperties();
    }
  }
  return false;
}

TaskbarPreview *
TaskbarPreview::sActivePreview = nullptr;

} // namespace widget
} // namespace mozilla