ProfileViewer: Convert the JSON samples into a more efficient format

Only do the conversion from JSON once. This makes it much faster to do
time range filtering with the timeline widget. :^)

DevTools/ProfileViewer/Profile.cpp

@@ -11,14 +11,30 @@ Profile::Profile(const JsonArray& json)
  m_last_timestamp = m_json.at(m_json.size() - 1).as_object().get("timestamp").to_number<u64>();
 
  m_model = ProfileModel::create(*this);
- rebuild_tree();
 
- m_sample_data.ensure_capacity(m_json.size());
- m_json.for_each([&](const JsonValue& sample) {
- u64 timestamp = sample.as_object().get("timestamp").to_number<u64>() - m_first_timestamp;
- bool in_kernel = sample.as_object().get("frames").as_array().at(1).as_object().get("address").to_number<u32>() < (8 * MB);
- m_sample_data.append({ timestamp, in_kernel });
- });
+ m_samples.ensure_capacity(m_json.size());
+ for (auto& sample_value : m_json.values()) {
+ auto& sample_object = sample_value.as_object();
+
+ Sample sample;
+ sample.timestamp = sample_object.get("timestamp").to_number<u64>();
+ sample.in_kernel = sample_object.get("frames").as_array().at(1).as_object().get("address").to_number<u32>() < (8 * MB);
+
+ auto frames_value = sample_object.get("frames");
+ auto& frames_array = frames_value.as_array();
+ for (int i = frames_array.size() - 1; i >= 0; --i) {
+ auto& frame_value = frames_array.at(i);
+ auto& frame_object = frame_value.as_object();
+ Frame frame;
+ frame.symbol = frame_object.get("symbol").as_string_or({});
+ frame.address = frame_object.get("address").as_u32();
+ frame.offset = frame_object.get("offset").as_u32();
+ sample.frames.append(move(frame));
+ };
+ m_samples.append(move(sample));
+ }
+
+ rebuild_tree();
 }
 
 Profile::~Profile()
@@ -46,35 +62,32 @@ void Profile::rebuild_tree()
  return new_root;
  };
 
- m_json.for_each([&](const JsonValue& sample) {
+ for (auto& sample : m_samples) {
  if (has_timestamp_filter_range()) {
- auto timestamp = sample.as_object().get("timestamp").to_number<u64>();
+ auto timestamp = sample.timestamp;
  if (timestamp < m_timestamp_filter_range_start || timestamp > m_timestamp_filter_range_end)
- return;
+ continue;
  }
 
- auto frames_value = sample.as_object().get("frames");
- auto& frames = frames_value.as_array();
  ProfileNode* node = nullptr;
- for (int i = frames.size() - 1; i >= 0; --i) {
- auto& frame = frames.at(i);
+ for (int i = 0; i < sample.frames.size(); ++i) {
+ auto& frame = sample.frames.at(i);
 
- auto symbol = frame.as_object().get("symbol").as_string_or({});
- auto address = frame.as_object().get("address").as_u32();
- auto offset = frame.as_object().get("offset").as_u32();
- auto timestamp = frame.as_object().get("timestamp").to_number<u64>();
+ auto& symbol = frame.symbol;
+ auto& address = frame.address;
+ auto& offset = frame.offset;
 
  if (symbol.is_empty())
  break;
 
  if (!node)
- node = &find_or_create_root(symbol, address, offset, timestamp);
+ node = &find_or_create_root(symbol, address, offset, sample.timestamp);
  else
- node = &node->find_or_create_child(symbol, address, offset, timestamp);
+ node = &node->find_or_create_child(symbol, address, offset, sample.timestamp);
 
  node->increment_sample_count();
  }
- });
+ }
 
  for (auto& root : roots) {
  root.sort_children();

DevTools/ProfileViewer/Profile.h

@@ -82,20 +82,19 @@ class Profile {
 
  const Vector<NonnullRefPtr<ProfileNode>>& roots() const { return m_roots; }
 
- template<typename Callback>
- void for_each_sample(Callback callback)
- {
- m_json.for_each([&](auto& value) {
- callback(value.as_object());
- });
- }
+ struct Frame {
+ String symbol;
+ u32 address { 0 };
+ u32 offset { 0 };
+ };
 
- struct SampleData {
+ struct Sample {
  u64 timestamp { 0 };
  bool in_kernel { false };
+ Vector<Frame> frames;
  };
 
- const Vector<SampleData>& sample_data() const { return m_sample_data; }
+ const Vector<Sample>& samples() const { return m_samples; }
 
  u64 length_in_ms() const { return m_last_timestamp - m_first_timestamp; }
  u64 first_timestamp() const { return m_first_timestamp; }
@@ -116,7 +115,7 @@ class Profile {
  u64 m_first_timestamp { 0 };
  u64 m_last_timestamp { 0 };
 
- Vector<SampleData> m_sample_data;
+ Vector<Sample> m_samples;
 
  bool m_has_timestamp_filter_range { false };
  u64 m_timestamp_filter_range_start { 0 };

DevTools/ProfileViewer/ProfileTimelineWidget.cpp

@@ -28,8 +28,8 @@ void ProfileTimelineWidget::paint_event(GPaintEvent& event)
 
  float column_width = (float)frame_inner_rect().width() / (float)m_profile.length_in_ms();
 
- for (auto& sample : m_profile.sample_data()) {
- u64 t = sample.timestamp;
+ for (auto& sample : m_profile.samples()) {
+ u64 t = sample.timestamp - m_profile.first_timestamp();
  int x = (int)((float)t * column_width);
  int cw = max(1, (int)column_width);