1 files changed, 175 insertions, 0 deletions
diff --git a/gfx/layers/ReadbackProcessor.cpp b/gfx/layers/ReadbackProcessor.cpp
new file mode 100644
index 0000000000..1e5e21c086
--- /dev/null
+++ b/gfx/layers/ReadbackProcessor.cpp
@@ -0,0 +1,175 @@
+/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* vim: set ts=8 sts=2 et sw=2 tw=80: */
+/* 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 "ReadbackProcessor.h"
+#include <sys/types.h>       // for int32_t
+#include "Layers.h"          // for Layer, PaintedLayer, etc
+#include "ReadbackLayer.h"   // for ReadbackLayer, ReadbackSink
+#include "UnitTransforms.h"  // for ViewAs
+#include "Units.h"           // for ParentLayerIntRect
+#include "gfxContext.h"      // for gfxContext
+#include "gfxUtils.h"
+#include "gfxRect.h"  // for gfxRect
+#include "mozilla/gfx/2D.h"
+#include "mozilla/gfx/BasePoint.h"  // for BasePoint
+#include "mozilla/gfx/BaseRect.h"   // for BaseRect
+#include "mozilla/gfx/Point.h"      // for Intsize
+#include "nsDebug.h"                // for NS_ASSERTION
+#include "nsISupportsImpl.h"        // for gfxContext::Release, etc
+#include "nsPoint.h"                // for nsIntPoint
+#include "nsRegion.h"               // for nsIntRegion
+
+using namespace mozilla::gfx;
+
+namespace mozilla {
+namespace layers {
+
+void ReadbackProcessor::BuildUpdates(ContainerLayer* aContainer) {
+  NS_ASSERTION(mAllUpdates.IsEmpty(), "Some updates not processed?");
+
+  if (!aContainer->mMayHaveReadbackChild) return;
+
+  aContainer->mMayHaveReadbackChild = false;
+  // go backwards so the updates read from earlier layers are later in the
+  // array.
+  for (Layer* l = aContainer->GetLastChild(); l; l = l->GetPrevSibling()) {
+    if (l->GetType() == Layer::TYPE_READBACK) {
+      aContainer->mMayHaveReadbackChild = true;
+      BuildUpdatesForLayer(static_cast<ReadbackLayer*>(l));
+    }
+  }
+}
+
+static Layer* FindBackgroundLayer(ReadbackLayer* aLayer, nsIntPoint* aOffset) {
+  gfx::Matrix transform;
+  if (!aLayer->GetTransform().Is2D(&transform) ||
+      transform.HasNonIntegerTranslation())
+    return nullptr;
+  nsIntPoint transformOffset(int32_t(transform._31), int32_t(transform._32));
+
+  for (Layer* l = aLayer->GetPrevSibling(); l; l = l->GetPrevSibling()) {
+    gfx::Matrix backgroundTransform;
+    if (!l->GetTransform().Is2D(&backgroundTransform) ||
+        gfx::ThebesMatrix(backgroundTransform).HasNonIntegerTranslation())
+      return nullptr;
+
+    nsIntPoint backgroundOffset(int32_t(backgroundTransform._31),
+                                int32_t(backgroundTransform._32));
+    IntRect rectInBackground(transformOffset - backgroundOffset,
+                             aLayer->GetSize());
+    const nsIntRegion visibleRegion =
+        l->GetLocalVisibleRegion().ToUnknownRegion();
+    if (!visibleRegion.Intersects(rectInBackground)) continue;
+    // Since l is present in the background, from here on we either choose l
+    // or nothing.
+    if (!visibleRegion.Contains(rectInBackground)) return nullptr;
+
+    if (l->GetEffectiveOpacity() != 1.0 || l->HasMaskLayers() ||
+        !(l->GetContentFlags() & Layer::CONTENT_OPAQUE)) {
+      return nullptr;
+    }
+
+    // cliprects are post-transform
+    const Maybe<ParentLayerIntRect>& clipRect = l->GetLocalClipRect();
+    if (clipRect && !clipRect->Contains(ViewAs<ParentLayerPixel>(
+                        IntRect(transformOffset, aLayer->GetSize()))))
+      return nullptr;
+
+    Layer::LayerType type = l->GetType();
+    if (type != Layer::TYPE_COLOR && type != Layer::TYPE_PAINTED)
+      return nullptr;
+
+    *aOffset = backgroundOffset - transformOffset;
+    return l;
+  }
+
+  return nullptr;
+}
+
+void ReadbackProcessor::BuildUpdatesForLayer(ReadbackLayer* aLayer) {
+  if (!aLayer->mSink) return;
+
+  nsIntPoint offset;
+  Layer* newBackground = FindBackgroundLayer(aLayer, &offset);
+  if (!newBackground) {
+    aLayer->SetUnknown();
+    return;
+  }
+
+  if (newBackground->GetType() == Layer::TYPE_COLOR) {
+    ColorLayer* colorLayer = static_cast<ColorLayer*>(newBackground);
+    if (aLayer->mBackgroundColor != colorLayer->GetColor()) {
+      aLayer->mBackgroundLayer = nullptr;
+      aLayer->mBackgroundColor = colorLayer->GetColor();
+      NS_ASSERTION(aLayer->mBackgroundColor.a == 1.f,
+                   "Color layer said it was opaque!");
+      RefPtr<DrawTarget> dt = aLayer->mSink->BeginUpdate(
+          aLayer->GetRect(), aLayer->AllocateSequenceNumber());
+      if (dt) {
+        ColorPattern color(aLayer->mBackgroundColor);
+        IntSize size = aLayer->GetSize();
+        dt->FillRect(Rect(0, 0, size.width, size.height), color);
+        aLayer->mSink->EndUpdate(aLayer->GetRect());
+      }
+    }
+  } else {
+    NS_ASSERTION(newBackground->AsPaintedLayer(), "Must be PaintedLayer");
+    PaintedLayer* paintedLayer = static_cast<PaintedLayer*>(newBackground);
+    // updateRect is relative to the PaintedLayer
+    IntRect updateRect = aLayer->GetRect() - offset;
+    if (paintedLayer != aLayer->mBackgroundLayer ||
+        offset != aLayer->mBackgroundLayerOffset) {
+      aLayer->mBackgroundLayer = paintedLayer;
+      aLayer->mBackgroundLayerOffset = offset;
+      aLayer->mBackgroundColor = DeviceColor();
+      paintedLayer->SetUsedForReadback(true);
+    } else {
+      nsIntRegion invalid;
+      invalid.Sub(updateRect, paintedLayer->GetValidRegion());
+      updateRect = invalid.GetBounds();
+    }
+
+    Update update = {aLayer, updateRect, aLayer->AllocateSequenceNumber()};
+    mAllUpdates.AppendElement(update);
+  }
+}
+
+void ReadbackProcessor::GetPaintedLayerUpdates(PaintedLayer* aLayer,
+                                               nsTArray<Update>* aUpdates,
+                                               nsIntRegion* aUpdateRegion) {
+  // All PaintedLayers used for readback are in mAllUpdates (some possibly
+  // with an empty update rect).
+  aLayer->SetUsedForReadback(false);
+  if (aUpdateRegion) {
+    aUpdateRegion->SetEmpty();
+  }
+  for (uint32_t i = mAllUpdates.Length(); i > 0; --i) {
+    const Update& update = mAllUpdates[i - 1];
+    if (update.mLayer->mBackgroundLayer == aLayer) {
+      aLayer->SetUsedForReadback(true);
+      // Don't bother asking for updates if we have an empty update rect.
+      if (!update.mUpdateRect.IsEmpty()) {
+        aUpdates->AppendElement(update);
+        if (aUpdateRegion) {
+          aUpdateRegion->Or(*aUpdateRegion, update.mUpdateRect);
+        }
+      }
+      mAllUpdates.RemoveElementAt(i - 1);
+    }
+  }
+}
+
+ReadbackProcessor::~ReadbackProcessor() {
+  for (uint32_t i = mAllUpdates.Length(); i > 0; --i) {
+    const Update& update = mAllUpdates[i - 1];
+    // Unprocessed update. Notify the readback sink that this content is
+    // unknown.
+    update.mLayer->SetUnknown();
+  }
+}
+
+}  // namespace layers
+}  // namespace mozilla