1 files changed, 273 insertions, 0 deletions
diff --git a/gfx/layers/apz/test/gtest/TestWRScrollData.cpp b/gfx/layers/apz/test/gtest/TestWRScrollData.cpp
new file mode 100644
index 0000000000..e267e58e90
--- /dev/null
+++ b/gfx/layers/apz/test/gtest/TestWRScrollData.cpp
@@ -0,0 +1,273 @@
+/* -*- 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 "TestWRScrollData.h"
+#include "APZTestAccess.h"
+#include "gtest/gtest.h"
+#include "FrameMetrics.h"
+#include "gfxPlatform.h"
+#include "mozilla/layers/APZUpdater.h"
+#include "mozilla/layers/LayersTypes.h"
+#include "mozilla/layers/ScrollableLayerGuid.h"
+#include "mozilla/layers/WebRenderScrollDataWrapper.h"
+#include "mozilla/UniquePtr.h"
+#include "apz/src/APZCTreeManager.h"
+
+using mozilla::layers::APZCTreeManager;
+using mozilla::layers::APZUpdater;
+using mozilla::layers::LayersId;
+using mozilla::layers::ScrollableLayerGuid;
+using mozilla::layers::ScrollMetadata;
+using mozilla::layers::TestWRScrollData;
+using mozilla::layers::WebRenderLayerScrollData;
+using mozilla::layers::WebRenderScrollDataWrapper;
+
+/* static */
+TestWRScrollData TestWRScrollData::Create(const char* aTreeShape,
+                                          const APZUpdater& aUpdater,
+                                          const LayerIntRegion* aVisibleRegions,
+                                          const gfx::Matrix4x4* aTransforms) {
+  // The WebRenderLayerScrollData tree needs to be created in a fairly
+  // particular way (for example, each node needs to know the number of
+  // descendants it has), so this function takes care to create the nodes
+  // in the same order as WebRenderCommandBuilder would.
+  TestWRScrollData result;
+  const size_t len = strlen(aTreeShape);
+  // "Layer index" in this function refers to the index by which a layer will
+  // be accessible via TestWRScrollData::GetLayer(), and matches the order
+  // in which the layer appears in |aTreeShape|.
+  size_t currentLayerIndex = 0;
+  struct LayerEntry {
+    size_t mLayerIndex;
+    int32_t mDescendantCount = 0;
+  };
+  // Layers we have encountered in |aTreeShape|, but have not built a
+  // WebRenderLayerScrollData for. (It can only be built after its
+  // descendants have been encountered and counted.)
+  std::stack<LayerEntry> pendingLayers;
+  std::vector<WebRenderLayerScrollData> finishedLayers;
+  // Tracks the level of nesting of '(' characters. Starts at 1 to account
+  // for the root layer.
+  size_t depth = 1;
+  // Helper function for finishing a layer once all its descendants have been
+  // encountered.
+  auto finishLayer = [&] {
+    MOZ_ASSERT(!pendingLayers.empty());
+    LayerEntry entry = pendingLayers.top();
+
+    WebRenderLayerScrollData layer;
+    APZTestAccess::InitializeForTest(layer, entry.mDescendantCount);
+    if (aVisibleRegions) {
+      layer.SetVisibleRegion(aVisibleRegions[entry.mLayerIndex]);
+    }
+    if (aTransforms) {
+      layer.SetTransform(aTransforms[entry.mLayerIndex]);
+    }
+    finishedLayers.push_back(std::move(layer));
+
+    // |finishedLayers| stores the layers in a different order than they
+    // appeared in |aTreeShape|. To be able to access layers by their layer
+    // index, keep a mapping from layer index to index in |finishedLayers|.
+    result.mIndexMap.emplace(entry.mLayerIndex, finishedLayers.size() - 1);
+
+    pendingLayers.pop();
+
+    // Keep track of descendant counts. The +1 is for the layer just finished.
+    if (!pendingLayers.empty()) {
+      pendingLayers.top().mDescendantCount += (entry.mDescendantCount + 1);
+    }
+  };
+  for (size_t i = 0; i < len; ++i) {
+    if (aTreeShape[i] == '(') {
+      ++depth;
+    } else if (aTreeShape[i] == ')') {
+      if (pendingLayers.size() <= 1) {
+        printf("Invalid tree shape: too many ')'\n");
+        MOZ_CRASH();
+      }
+      finishLayer();  // finish last layer at current depth
+      --depth;
+    } else {
+      if (aTreeShape[i] != 'x') {
+        printf("The only allowed character to represent a layer is 'x'\n");
+        MOZ_CRASH();
+      }
+      if (depth == pendingLayers.size()) {
+        // We have a previous layer at this same depth to finish.
+        if (depth <= 1) {
+          printf("The tree is only allowed to have one root\n");
+          MOZ_CRASH();
+        }
+        finishLayer();
+      }
+      MOZ_ASSERT(depth == pendingLayers.size() + 1);
+      pendingLayers.push({currentLayerIndex});
+      ++currentLayerIndex;
+    }
+  }
+  if (pendingLayers.size() != 1) {
+    printf("Invalid tree shape: '(' and ')' not balanced\n");
+    MOZ_CRASH();
+  }
+  finishLayer();  // finish root layer
+
+  // As in WebRenderCommandBuilder, the layers need to be added to the
+  // WebRenderScrollData in reverse of the order in which they were built.
+  for (auto it = finishedLayers.rbegin(); it != finishedLayers.rend(); ++it) {
+    result.AddLayerData(std::move(*it));
+  }
+  // mIndexMap also needs to be adjusted to accout for the reversal above.
+  for (auto& [layerIndex, storedIndex] : result.mIndexMap) {
+    (void)layerIndex;  // suppress -Werror=unused-variable
+    storedIndex = result.GetLayerCount() - storedIndex - 1;
+  }
+
+  return result;
+}
+
+const WebRenderLayerScrollData* TestWRScrollData::operator[](
+    size_t aLayerIndex) const {
+  auto it = mIndexMap.find(aLayerIndex);
+  if (it == mIndexMap.end()) {
+    return nullptr;
+  }
+  return GetLayerData(it->second);
+}
+
+WebRenderLayerScrollData* TestWRScrollData::operator[](size_t aLayerIndex) {
+  auto it = mIndexMap.find(aLayerIndex);
+  if (it == mIndexMap.end()) {
+    return nullptr;
+  }
+  return GetLayerData(it->second);
+}
+
+void TestWRScrollData::SetScrollMetadata(
+    size_t aLayerIndex, const nsTArray<ScrollMetadata>& aMetadata) {
+  WebRenderLayerScrollData* layer = operator[](aLayerIndex);
+  MOZ_ASSERT(layer);
+  for (const ScrollMetadata& metadata : aMetadata) {
+    layer->AppendScrollMetadata(*this, metadata);
+  }
+}
+
+class WebRenderScrollDataWrapperTester : public ::testing::Test {
+ protected:
+  virtual void SetUp() {
+    // This ensures ScrollMetadata::sNullMetadata is initialized.
+    gfxPlatform::GetPlatform();
+
+    mManager = new APZCTreeManager(LayersId{0});
+    mUpdater = new APZUpdater(mManager, false);
+  }
+
+  RefPtr<APZCTreeManager> mManager;
+  RefPtr<APZUpdater> mUpdater;
+};
+
+TEST_F(WebRenderScrollDataWrapperTester, SimpleTree) {
+  auto layers = TestWRScrollData::Create("x(x(x(xx)x(x)))", *mUpdater);
+  WebRenderScrollDataWrapper w0(*mUpdater, &layers);
+
+  ASSERT_EQ(layers[0], w0.GetLayer());
+  WebRenderScrollDataWrapper w1 = w0.GetLastChild();
+  ASSERT_EQ(layers[1], w1.GetLayer());
+  ASSERT_FALSE(w1.GetPrevSibling().IsValid());
+  WebRenderScrollDataWrapper w5 = w1.GetLastChild();
+  ASSERT_EQ(layers[5], w5.GetLayer());
+  WebRenderScrollDataWrapper w6 = w5.GetLastChild();
+  ASSERT_EQ(layers[6], w6.GetLayer());
+  ASSERT_FALSE(w6.GetLastChild().IsValid());
+  WebRenderScrollDataWrapper w2 = w5.GetPrevSibling();
+  ASSERT_EQ(layers[2], w2.GetLayer());
+  ASSERT_FALSE(w2.GetPrevSibling().IsValid());
+  WebRenderScrollDataWrapper w4 = w2.GetLastChild();
+  ASSERT_EQ(layers[4], w4.GetLayer());
+  ASSERT_FALSE(w4.GetLastChild().IsValid());
+  WebRenderScrollDataWrapper w3 = w4.GetPrevSibling();
+  ASSERT_EQ(layers[3], w3.GetLayer());
+  ASSERT_FALSE(w3.GetLastChild().IsValid());
+  ASSERT_FALSE(w3.GetPrevSibling().IsValid());
+}
+
+static ScrollMetadata MakeMetadata(ScrollableLayerGuid::ViewID aId) {
+  ScrollMetadata metadata;
+  metadata.GetMetrics().SetScrollId(aId);
+  return metadata;
+}
+
+TEST_F(WebRenderScrollDataWrapperTester, MultiFramemetricsTree) {
+  auto layers = TestWRScrollData::Create("x(x(x(xx)x(x)))", *mUpdater);
+
+  nsTArray<ScrollMetadata> metadata;
+  metadata.InsertElementAt(0,
+                           MakeMetadata(ScrollableLayerGuid::START_SCROLL_ID +
+                                        0));  // topmost of root layer
+  metadata.InsertElementAt(0,
+                           MakeMetadata(ScrollableLayerGuid::NULL_SCROLL_ID));
+  metadata.InsertElementAt(
+      0, MakeMetadata(ScrollableLayerGuid::START_SCROLL_ID + 1));
+  metadata.InsertElementAt(
+      0, MakeMetadata(ScrollableLayerGuid::START_SCROLL_ID + 2));
+  metadata.InsertElementAt(0,
+                           MakeMetadata(ScrollableLayerGuid::NULL_SCROLL_ID));
+  metadata.InsertElementAt(
+      0, MakeMetadata(
+             ScrollableLayerGuid::NULL_SCROLL_ID));  // bottom of root layer
+  layers.SetScrollMetadata(0, metadata);
+
+  metadata.Clear();
+  metadata.InsertElementAt(
+      0, MakeMetadata(ScrollableLayerGuid::START_SCROLL_ID + 3));
+  layers.SetScrollMetadata(1, metadata);
+
+  metadata.Clear();
+  metadata.InsertElementAt(
+      0, MakeMetadata(ScrollableLayerGuid::START_SCROLL_ID + 4));
+  layers.SetScrollMetadata(2, metadata);
+
+  metadata.Clear();
+  metadata.InsertElementAt(
+      0, MakeMetadata(ScrollableLayerGuid::START_SCROLL_ID + 5));
+  layers.SetScrollMetadata(4, metadata);
+
+  metadata.Clear();
+  metadata.InsertElementAt(0,
+                           MakeMetadata(ScrollableLayerGuid::NULL_SCROLL_ID));
+  metadata.InsertElementAt(
+      0, MakeMetadata(ScrollableLayerGuid::START_SCROLL_ID + 6));
+  layers.SetScrollMetadata(5, metadata);
+
+  WebRenderScrollDataWrapper wrapper(*mUpdater, &layers);
+  nsTArray<WebRenderLayerScrollData*> expectedLayers;
+  expectedLayers.AppendElement(layers[0]);
+  expectedLayers.AppendElement(layers[0]);
+  expectedLayers.AppendElement(layers[0]);
+  expectedLayers.AppendElement(layers[0]);
+  expectedLayers.AppendElement(layers[0]);
+  expectedLayers.AppendElement(layers[0]);
+  expectedLayers.AppendElement(layers[1]);
+  expectedLayers.AppendElement(layers[5]);
+  expectedLayers.AppendElement(layers[5]);
+  expectedLayers.AppendElement(layers[6]);
+  nsTArray<ScrollableLayerGuid::ViewID> expectedIds;
+  expectedIds.AppendElement(ScrollableLayerGuid::START_SCROLL_ID + 0);
+  expectedIds.AppendElement(ScrollableLayerGuid::NULL_SCROLL_ID);
+  expectedIds.AppendElement(ScrollableLayerGuid::START_SCROLL_ID + 1);
+  expectedIds.AppendElement(ScrollableLayerGuid::START_SCROLL_ID + 2);
+  expectedIds.AppendElement(ScrollableLayerGuid::NULL_SCROLL_ID);
+  expectedIds.AppendElement(ScrollableLayerGuid::NULL_SCROLL_ID);
+  expectedIds.AppendElement(ScrollableLayerGuid::START_SCROLL_ID + 3);
+  expectedIds.AppendElement(ScrollableLayerGuid::NULL_SCROLL_ID);
+  expectedIds.AppendElement(ScrollableLayerGuid::START_SCROLL_ID + 6);
+  expectedIds.AppendElement(ScrollableLayerGuid::NULL_SCROLL_ID);
+  for (int i = 0; i < 10; i++) {
+    ASSERT_EQ(expectedLayers[i], wrapper.GetLayer());
+    ASSERT_EQ(expectedIds[i], wrapper.Metrics().GetScrollId());
+    wrapper = wrapper.GetLastChild();
+  }
+  ASSERT_FALSE(wrapper.IsValid());
+}