Separate out the backing store from the RenderWidgetHost into its own file to

make porting easier.

I also did some cleanup in the scrolling and painting areas, collapsing the
confusing ScrollRect call inside OnMsgScrollRect to just be inside the function
and call a new function on the backing store to scroll it. Same for painting.

This also moves plugin window moving to the view.
Review URL: http://codereview.chromium.org/18702

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@8594 0039d316-1c4b-4281-b951-d872f2087c98

1 files changed, 243 insertions, 0 deletions

diff --git a/chrome/browser/renderer_host/backing_store.cc b/chrome/browser/renderer_host/backing_store.cc
new file mode 100644
index 0000000..c12d0bd
--- /dev/null
+++ b/chrome/browser/renderer_host/backing_store.cc
@@ -0,0 +1,243 @@
+// Copyright (c) 2006-2008 The Chromium Authors. All rights reserved.

+// Use of this source code is governed by a BSD-style license that can be

+// found in the LICENSE file.

+

+#include "chrome/browser/renderer_host/backing_store.h"

+

+#include "chrome/browser/renderer_host/render_widget_host.h"

+#include "chrome/common/win_util.h"

+

+#if defined(OS_WIN)

+#include "base/gfx/gdi_util.h"

+#endif

+

+namespace {

+

+typedef OwningMRUCache<RenderWidgetHost*, BackingStore*> BackingStoreCache;

+static BackingStoreCache* cache = NULL;

+

+// Returns the size of the backing store cache.

+// TODO(iyengar) Make this dynamic, i.e. based on the available resources

+// on the machine.

+static int GetBackingStoreCacheSize() {

+  const int kMaxSize = 5;

+  return kMaxSize;

+}

+

+// Creates the backing store for the host based on the dimensions passed in.

+// Removes the existing backing store if there is one.

+BackingStore* CreateBackingStore(RenderWidgetHost* host,

+                                 const gfx::Rect& backing_store_rect) {

+  BackingStoreManager::RemoveBackingStore(host);

+

+  BackingStore* backing_store = new BackingStore(backing_store_rect.size());

+  int backing_store_cache_size = GetBackingStoreCacheSize();

+  if (backing_store_cache_size > 0) {

+    if (!cache)

+      cache = new BackingStoreCache(backing_store_cache_size);

+    cache->Put(host, backing_store);

+  }

+  return backing_store;

+}

+

+}  // namespace

+

+#if defined(OS_WIN)

+

+// BackingStore (Windows) ------------------------------------------------------

+

+BackingStore::BackingStore(const gfx::Size& size)

+    : size_(size),

+      backing_store_dib_(NULL),

+      original_bitmap_(NULL) {

+  HDC screen_dc = ::GetDC(NULL);

+  hdc_ = CreateCompatibleDC(screen_dc);

+  ReleaseDC(NULL, screen_dc);

+}

+

+BackingStore::~BackingStore() {

+  DCHECK(hdc_);

+

+  DeleteDC(hdc_);

+

+  if (backing_store_dib_) {

+    DeleteObject(backing_store_dib_);

+    backing_store_dib_ = NULL;

+  }

+}

+

+bool BackingStore::PaintRect(base::ProcessHandle process,

+                             HANDLE bitmap_section,

+                             const gfx::Rect& bitmap_rect) {

+  // The bitmap received is valid only in the renderer process.

+  HANDLE valid_bitmap =

+      win_util::GetSectionFromProcess(bitmap_section, process, false);

+  if (!valid_bitmap)

+    return false;

+

+  if (!backing_store_dib_) {

+    backing_store_dib_ = CreateDIB(hdc_, size_.width(), size_.height(), true,

+                                   NULL);

+    DCHECK(backing_store_dib_ != NULL);

+    original_bitmap_ = SelectObject(hdc_, backing_store_dib_);

+  }

+

+  // TODO(darin): protect against integer overflow

+  DWORD size = 4 * bitmap_rect.width() * bitmap_rect.height();

+  void* backing_store_data = MapViewOfFile(valid_bitmap, FILE_MAP_READ, 0, 0,

+                                           size);

+  // These values are shared with gfx::PlatformDevice

+  BITMAPINFOHEADER hdr;

+  gfx::CreateBitmapHeader(bitmap_rect.width(), bitmap_rect.height(), &hdr);

+  // Account for a bitmap_rect that exceeds the bounds of our view

+  gfx::Rect view_rect(0, 0, size_.width(), size_.height());

+  gfx::Rect paint_rect = view_rect.Intersect(bitmap_rect);

+

+  StretchDIBits(hdc_,

+                paint_rect.x(),

+                paint_rect.y(),

+                paint_rect.width(),

+                paint_rect.height(),

+                0, 0,  // source x,y

+                paint_rect.width(),

+                paint_rect.height(),

+                backing_store_data,

+                reinterpret_cast<BITMAPINFO*>(&hdr),

+                DIB_RGB_COLORS,

+                SRCCOPY);

+

+  UnmapViewOfFile(backing_store_data);

+  CloseHandle(valid_bitmap);

+  return true;

+}

+

+void BackingStore::ScrollRect(base::ProcessHandle process,

+                              HANDLE bitmap, const gfx::Rect& bitmap_rect,

+                              int dx, int dy,

+                              const gfx::Rect& clip_rect,

+                              const gfx::Size& view_size) {

+  RECT damaged_rect, r = clip_rect.ToRECT();

+  ScrollDC(hdc_, dx, dy, NULL, &r, NULL, &damaged_rect);

+

+  // TODO(darin): this doesn't work if dx and dy are both non-zero!

+  DCHECK(dx == 0 || dy == 0);

+

+  // We expect that damaged_rect should equal bitmap_rect.

+  DCHECK(gfx::Rect(damaged_rect) == bitmap_rect);

+

+  PaintRect(process, bitmap, bitmap_rect);

+}

+

+HANDLE BackingStore::CreateDIB(HDC dc,

+                               int width, int height,

+                               bool use_system_color_depth,

+                               HANDLE section) {

+  BITMAPINFOHEADER hdr;

+

+  if (use_system_color_depth) {

+    HDC screen_dc = ::GetDC(NULL);

+    int color_depth = GetDeviceCaps(screen_dc, BITSPIXEL);

+    ::ReleaseDC(NULL, screen_dc);

+

+    // Color depths less than 16 bpp require a palette to be specified in the

+    // BITMAPINFO structure passed to CreateDIBSection. Instead of creating

+    // the palette, we specify the desired color depth as 16 which allows the

+    // OS to come up with an approximation. Tested this with 8bpp.

+    if (color_depth < 16)

+      color_depth = 16;

+

+    gfx::CreateBitmapHeaderWithColorDepth(width, height, color_depth, &hdr);

+  } else {

+    gfx::CreateBitmapHeader(width, height, &hdr);

+  }

+  void* data = NULL;

+  HANDLE dib =

+      CreateDIBSection(hdc_, reinterpret_cast<BITMAPINFO*>(&hdr),

+                       0, &data, section, 0);

+  return dib;

+}

+

+#elif defined(OS_LINUX)

+

+// BackingStore (Linux) --------------------------------------------------------

+

+

+

+#elif defined(OS_MAC)

+

+// BackingStore (Mac) ----------------------------------------------------------

+

+

+

+#endif

+

+// BackingStoreManager ---------------------------------------------------------

+

+// static

+BackingStore* BackingStoreManager::GetBackingStore(

+    RenderWidgetHost* host,

+    const gfx::Size& desired_size) {

+  BackingStore* backing_store = Lookup(host);

+  if (backing_store) {

+    // If we already have a backing store, then make sure it is the correct

+    // size.

+    if (backing_store->size() == desired_size)

+      return backing_store;

+    backing_store = NULL;

+  }

+

+  return backing_store;

+}

+

+// static

+BackingStore* BackingStoreManager::PrepareBackingStore(

+    RenderWidgetHost* host,

+    const gfx::Rect& backing_store_rect,

+    HANDLE process_handle,

+    HANDLE bitmap_section,

+    const gfx::Rect& bitmap_rect,

+    bool* needs_full_paint) {

+  BackingStore* backing_store = GetBackingStore(host,

+                                                backing_store_rect.size());

+  if (!backing_store) {

+    // We need to get Webkit to generate a new paint here, as we

+    // don't have a previous snapshot.

+    if (bitmap_rect != backing_store_rect) {

+      DCHECK(needs_full_paint != NULL);

+      *needs_full_paint = true;

+    }

+    backing_store = CreateBackingStore(host, backing_store_rect);

+  }

+

+  DCHECK(backing_store != NULL);

+  backing_store->PaintRect(process_handle, bitmap_section, bitmap_rect);

+  return backing_store;

+}

+

+// static

+BackingStore* BackingStoreManager::Lookup(RenderWidgetHost* host) {

+  if (cache) {

+    BackingStoreCache::iterator it = cache->Peek(host);

+    if (it != cache->end())

+      return it->second;

+  }

+  return NULL;

+}

+

+// static

+void BackingStoreManager::RemoveBackingStore(RenderWidgetHost* host) {

+  if (!cache)

+    return;

+

+  BackingStoreCache::iterator it = cache->Peek(host);

+  if (it == cache->end())

+    return;

+

+  cache->Erase(it);

+

+  if (cache->empty()) {

+    delete cache;

+    cache = NULL;

+  }

+}

+