Eliminate duplicated code when dealing with pointer data (flutter#36822)

* add methods

* add empty test

* add unit test

* Update licenses_flutter

* add const

* size -> get length

* add boundary checks

* add tests

* remove death test since it says "Death tests use fork(), which is unsafe particularly in a threaded context."

ci/licenses_golden/licenses_flutter

@@ -1781,6 +1781,7 @@ FILE: ../../../flutter/lib/ui/window/pointer_data_packet.h
 FILE: ../../../flutter/lib/ui/window/pointer_data_packet_converter.cc
 FILE: ../../../flutter/lib/ui/window/pointer_data_packet_converter.h
 FILE: ../../../flutter/lib/ui/window/pointer_data_packet_converter_unittests.cc
+FILE: ../../../flutter/lib/ui/window/pointer_data_packet_unittests.cc
 FILE: ../../../flutter/lib/ui/window/viewport_metrics.cc
 FILE: ../../../flutter/lib/ui/window/viewport_metrics.h
 FILE: ../../../flutter/lib/ui/window/window.cc

lib/ui/BUILD.gn

@@ -239,6 +239,7 @@ if (enable_unittests) {
       "window/platform_message_response_dart_port_unittests.cc",
       "window/platform_message_response_dart_unittests.cc",
       "window/pointer_data_packet_converter_unittests.cc",
+      "window/pointer_data_packet_unittests.cc",
     ]
 
     deps = [

lib/ui/window/pointer_data_packet.cc

@@ -3,6 +3,7 @@
 // found in the LICENSE file.
 
 #include "flutter/lib/ui/window/pointer_data_packet.h"
+#include "flutter/fml/logging.h"
 
 #include <cstring>
 
@@ -17,7 +18,19 @@ PointerDataPacket::PointerDataPacket(uint8_t* data, size_t num_bytes)
 PointerDataPacket::~PointerDataPacket() = default;
 
 void PointerDataPacket::SetPointerData(size_t i, const PointerData& data) {
+  FML_DCHECK(i < GetLength());
   memcpy(&data_[i * sizeof(PointerData)], &data, sizeof(PointerData));
 }
 
+PointerData PointerDataPacket::GetPointerData(size_t i) const {
+  FML_DCHECK(i < GetLength());
+  PointerData result;
+  memcpy(&result, &data_[i * sizeof(PointerData)], sizeof(PointerData));
+  return result;
+}
+
+size_t PointerDataPacket::GetLength() const {
+  return data_.size() / sizeof(PointerData);
+}
+
 }  // namespace flutter

lib/ui/window/pointer_data_packet.h

@@ -20,6 +20,8 @@ class PointerDataPacket {
   ~PointerDataPacket();
 
   void SetPointerData(size_t i, const PointerData& data);
+  PointerData GetPointerData(size_t i) const;
+  size_t GetLength() const;
   const std::vector<uint8_t>& data() const { return data_; }
 
  private:

lib/ui/window/pointer_data_packet_converter.cc

@@ -17,17 +17,11 @@ PointerDataPacketConverter::~PointerDataPacketConverter() = default;
 
 std::unique_ptr<PointerDataPacket> PointerDataPacketConverter::Convert(
     std::unique_ptr<PointerDataPacket> packet) {
-  size_t kBytesPerPointerData = kPointerDataFieldCount * kBytesPerField;
-  auto buffer = packet->data();
-  size_t buffer_length = buffer.size();
-
   std::vector<PointerData> converted_pointers;
   // Converts each pointer data in the buffer and stores it in the
   // converted_pointers.
-  for (size_t i = 0; i < buffer_length / kBytesPerPointerData; i++) {
-    PointerData pointer_data;
-    memcpy(&pointer_data, &buffer[i * kBytesPerPointerData],
-           sizeof(PointerData));
+  for (size_t i = 0; i < packet->GetLength(); i++) {
+    PointerData pointer_data = packet->GetPointerData(i);
     ConvertPointerData(pointer_data, converted_pointers);
   }
 

lib/ui/window/pointer_data_packet_converter_unittests.cc

@@ -133,14 +133,8 @@ void CreateSimulatedTrackpadGestureData(PointerData& data,  // NOLINT
 
 void UnpackPointerPacket(std::vector<PointerData>& output,  // NOLINT
                          std::unique_ptr<PointerDataPacket> packet) {
-  size_t kBytesPerPointerData = kPointerDataFieldCount * kBytesPerField;
-  auto buffer = packet->data();
-  size_t buffer_length = buffer.size();
-
-  for (size_t i = 0; i < buffer_length / kBytesPerPointerData; i++) {
-    PointerData pointer_data;
-    memcpy(&pointer_data, &buffer[i * kBytesPerPointerData],
-           sizeof(PointerData));
+  for (size_t i = 0; i < packet->GetLength(); i++) {
+    PointerData pointer_data = packet->GetPointerData(i);
     output.push_back(pointer_data);
   }
   packet.reset();

lib/ui/window/pointer_data_packet_unittests.cc

@@ -0,0 +1,69 @@
+// Copyright 2013 The Flutter 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 "flutter/lib/ui/window/pointer_data.h"
+
+#include <cstring>
+
+#include "gtest/gtest.h"
+#include "pointer_data_packet.h"
+
+namespace flutter {
+namespace testing {
+
+void CreateSimpleSimulatedPointerData(PointerData& data,  // NOLINT
+                                      PointerData::Change change,
+                                      int64_t device,
+                                      double dx,
+                                      double dy,
+                                      int64_t buttons) {
+  data.time_stamp = 0;
+  data.change = change;
+  data.kind = PointerData::DeviceKind::kTouch;
+  data.signal_kind = PointerData::SignalKind::kNone;
+  data.device = device;
+  data.pointer_identifier = 0;
+  data.physical_x = dx;
+  data.physical_y = dy;
+  data.physical_delta_x = 0.0;
+  data.physical_delta_y = 0.0;
+  data.buttons = buttons;
+  data.obscured = 0;
+  data.synthesized = 0;
+  data.pressure = 0.0;
+  data.pressure_min = 0.0;
+  data.pressure_max = 0.0;
+  data.distance = 0.0;
+  data.distance_max = 0.0;
+  data.size = 0.0;
+  data.radius_major = 0.0;
+  data.radius_minor = 0.0;
+  data.radius_min = 0.0;
+  data.radius_max = 0.0;
+  data.orientation = 0.0;
+  data.tilt = 0.0;
+  data.platformData = 0;
+  data.scroll_delta_x = 0.0;
+  data.scroll_delta_y = 0.0;
+}
+
+TEST(PointerDataPacketTest, CanGetPointerData) {
+  auto packet = std::make_unique<PointerDataPacket>(1);
+  PointerData data;
+  CreateSimpleSimulatedPointerData(data, PointerData::Change::kAdd, 1, 2.0, 3.0,
+                                   4);
+  packet->SetPointerData(0, data);
+
+  PointerData data_recovered = packet->GetPointerData(0);
+  ASSERT_EQ(data_recovered.physical_x, 2.0);
+  ASSERT_EQ(data_recovered.physical_y, 3.0);
+}
+
+TEST(PointerDataPacketTest, CanGetLength) {
+  auto packet = std::make_unique<PointerDataPacket>(6);
+  ASSERT_EQ(packet->GetLength(), (size_t)6);
+}
+
+}  // namespace testing
+}  // namespace flutter

shell/platform/fuchsia/flutter/platform_view_unittest.cc

@@ -379,15 +379,8 @@ std::string ToString(const fml::Mapping& mapping) {
 // Stolen from pointer_data_packet_converter_unittests.cc.
 void UnpackPointerPacket(std::vector<flutter::PointerData>& output,  // NOLINT
                          std::unique_ptr<flutter::PointerDataPacket> packet) {
-  size_t kBytesPerPointerData =
-      flutter::kPointerDataFieldCount * flutter::kBytesPerField;
-  auto buffer = packet->data();
-  size_t buffer_length = buffer.size();
-
-  for (size_t i = 0; i < buffer_length / kBytesPerPointerData; i++) {
-    flutter::PointerData pointer_data;
-    memcpy(&pointer_data, &buffer[i * kBytesPerPointerData],
-           sizeof(flutter::PointerData));
+  for (size_t i = 0; i < packet->GetLength(); i++) {
+    flutter::PointerData pointer_data = packet->GetPointerData(i);
     output.push_back(pointer_data);
   }
   packet.reset();

shell/platform/fuchsia/flutter/tests/flatland_platform_view_unittest.cc

@@ -484,15 +484,8 @@ std::string ToString(const fml::Mapping& mapping) {
 // Stolen from pointer_data_packet_converter_unittests.cc.
 void UnpackPointerPacket(std::vector<flutter::PointerData>& output,  // NOLINT
                          std::unique_ptr<flutter::PointerDataPacket> packet) {
-  size_t kBytesPerPointerData =
-      flutter::kPointerDataFieldCount * flutter::kBytesPerField;
-  auto buffer = packet->data();
-  size_t buffer_length = buffer.size();
-
-  for (size_t i = 0; i < buffer_length / kBytesPerPointerData; i++) {
-    flutter::PointerData pointer_data;
-    memcpy(&pointer_data, &buffer[i * kBytesPerPointerData],
-           sizeof(flutter::PointerData));
+  for (size_t i = 0; i < packet->GetLength(); i++) {
+    flutter::PointerData pointer_data = packet->GetPointerData(i);
     output.push_back(pointer_data);
   }
   packet.reset();