Initial checkin of the new Mozart compositor.

services/gfx/compositor/compositor_engine.cc

+// Copyright 2015 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 "services/gfx/compositor/compositor_engine.h"
+
+#include <algorithm>
+#include <sstream>
+#include <utility>
+
+#include "base/bind.h"
+#include "base/bind_helpers.h"
+#include "base/time/time.h"
+#include "mojo/services/gfx/composition/cpp/logging.h"
+#include "services/gfx/compositor/backend/gpu_output.h"
+#include "services/gfx/compositor/graph/snapshot.h"
+#include "services/gfx/compositor/render/render_frame.h"
+#include "services/gfx/compositor/renderer_impl.h"
+#include "services/gfx/compositor/scene_impl.h"
+
+namespace compositor {
+
+// TODO(jeffbrown): Determine and document a more appropriate size limit
+// for viewports somewhere.  May be limited by the renderer output.
+static const int32_t kMaxViewportWidth = 65536;
+static const int32_t kMaxViewportHeight = 65536;
+
+CompositorEngine::CompositorEngine() : weak_factory_(this) {}
+
+CompositorEngine::~CompositorEngine() {}
+
+mojo::gfx::composition::SceneTokenPtr CompositorEngine::CreateScene(
+    mojo::InterfaceRequest<mojo::gfx::composition::Scene> scene_request,
+    const mojo::String& label) {
+  auto scene_token = mojo::gfx::composition::SceneToken::New();
+  scene_token->value = next_scene_token_value_++;
+  CHECK(scene_token->value);
+  CHECK(!FindScene(scene_token->value));
+
+  // Create the state and bind implementation to it.
+  std::string sanitized_label =
+      label.get().substr(0, mojo::gfx::composition::kLabelMaxLength);
+  SceneState* scene_state = new SceneState(scene_token.Pass(), sanitized_label);
+  SceneImpl* scene_impl =
+      new SceneImpl(this, scene_state, scene_request.Pass());
+  scene_state->set_scene_impl(scene_impl);
+  base::Closure error_handler =
+      base::Bind(&CompositorEngine::OnSceneConnectionError,
+                 base::Unretained(this), scene_state);
+  scene_impl->set_connection_error_handler(error_handler);
+
+  // Add to registry.
+  scenes_by_token_.insert({scene_state->scene_token()->value, scene_state});
+  DVLOG(1) << "CreateScene: scene=" << scene_state;
+  return scene_state->scene_token()->Clone();
+}
+
+void CompositorEngine::OnSceneConnectionError(SceneState* scene_state) {
+  DCHECK(IsSceneStateRegisteredDebug(scene_state));
+  DVLOG(1) << "OnSceneConnectionError: scene=" << scene_state;
+
+  DestroyScene(scene_state);
+}
+
+void CompositorEngine::DestroyScene(SceneState* scene_state) {
+  DCHECK(IsSceneStateRegisteredDebug(scene_state));
+  DVLOG(1) << "DestroyScene: scene=" << scene_state;
+
+  // Unlink from other scenes.
+  for (auto& pair : scenes_by_token_) {
+    SceneState* other_scene_state = pair.second;
+    other_scene_state->scene_def()->UnlinkReferencedScene(
+        scene_state->scene_def(),
+        base::Bind(&CompositorEngine::SendResourceUnavailable,
+                   base::Unretained(this),
+                   base::Unretained(other_scene_state)));
+  }
+
+  // Destroy any renderers using this scene.
+  for (auto& renderer : renderers_) {
+    if (renderer->root_scene() == scene_state) {
+      LOG(ERROR) << "Destroying renderer whose root scene has become "
+                    "unavailable: renderer="
+                 << renderer;
+      DestroyRenderer(renderer);
+    }
+  }
+
+  // Destroy.
+  InvalidateScene(scene_state);
+
+  // Remove from registry.
+  scenes_by_token_.erase(scene_state->scene_token()->value);
+  delete scene_state;
+}
+
+void CompositorEngine::CreateRenderer(
+    mojo::ContextProviderPtr context_provider,
+    mojo::InterfaceRequest<mojo::gfx::composition::Renderer> renderer_request,
+    const mojo::String& label) {
+  DCHECK(context_provider);
+  uint32_t renderer_id = next_renderer_id_++;
+
+  // Create the state and bind implementation to it.
+  std::string sanitized_label =
+      label.get().substr(0, mojo::gfx::composition::kLabelMaxLength);

[abarth, 2016/01/10 22:55:35]

This pattern recurs a bunch.  Maybe factor it out somewhere?

[jeffbrown, 2016/01/16 03:28:31]

Done.

+  RendererState* renderer_state =
+      new RendererState(renderer_id, sanitized_label);
+  RendererImpl* renderer_impl =
+      new RendererImpl(this, renderer_state, renderer_request.Pass());
+  renderer_state->set_renderer_impl(renderer_impl);
+  renderer_impl->set_connection_error_handler(
+      base::Bind(&CompositorEngine::OnRendererConnectionError,
+                 base::Unretained(this), renderer_state));
+
+  // Create the renderer.
+  SchedulerCallbacks scheduler_callbacks(
+      base::Bind(&CompositorEngine::OnOutputUpdateRequest,
+                 weak_factory_.GetWeakPtr(), renderer_state->GetWeakPtr()),
+      base::Bind(&CompositorEngine::OnOutputSnapshotRequest,
+                 weak_factory_.GetWeakPtr(), renderer_state->GetWeakPtr()));
+  std::unique_ptr<Output> output(new GpuOutput(
+      context_provider.Pass(), scheduler_callbacks,
+      base::Bind(&CompositorEngine::OnOutputError, weak_factory_.GetWeakPtr(),
+                 renderer_state->GetWeakPtr())));
+  renderer_state->set_output(std::move(output));
+
+  // Add to registry.
+  renderers_.push_back(renderer_state);
+  DVLOG(1) << "CreateRenderer: " << renderer_state;
+}
+
+void CompositorEngine::OnRendererConnectionError(
+    RendererState* renderer_state) {
+  DCHECK(IsRendererStateRegisteredDebug(renderer_state));
+  DVLOG(1) << "OnRendererConnectionError: renderer=" << renderer_state;
+
+  DestroyRenderer(renderer_state);
+}
+
+void CompositorEngine::DestroyRenderer(RendererState* renderer_state) {
+  DCHECK(IsRendererStateRegisteredDebug(renderer_state));
+  DVLOG(1) << "DestroyRenderer: renderer=" << renderer_state;
+
+  // Remove from registry.
+  renderers_.erase(
+      std::find(renderers_.begin(), renderers_.end(), renderer_state));
+  delete renderer_state;
+}
+
+void CompositorEngine::SetListener(
+    SceneState* scene_state,
+    mojo::gfx::composition::SceneListenerPtr listener) {
+  DCHECK(IsSceneStateRegisteredDebug(scene_state));
+  DVLOG(1) << "SetSceneListener: scene=" << scene_state;
+
+  scene_state->set_scene_listener(listener.Pass());
+}
+
+void CompositorEngine::Update(SceneState* scene_state,
+                              mojo::gfx::composition::SceneUpdatePtr update) {
+  DCHECK(IsSceneStateRegisteredDebug(scene_state));
+  DVLOG(1) << "Update: scene=" << scene_state << ", update=" << update;
+
+  scene_state->scene_def()->EnqueueUpdate(update.Pass());
+}
+
+void CompositorEngine::Publish(
+    SceneState* scene_state,
+    mojo::gfx::composition::SceneMetadataPtr metadata) {
+  DCHECK(IsSceneStateRegisteredDebug(scene_state));
+  DVLOG(1) << "Publish: scene=" << scene_state << ", metadata=" << metadata;
+
+  if (!metadata)
+    metadata = mojo::gfx::composition::SceneMetadata::New();
+  int64_t presentation_time = metadata->presentation_time;
+  scene_state->scene_def()->EnqueuePublish(metadata.Pass());
+
+  // Implicitly schedule fresh snapshots.
+  InvalidateScene(scene_state);
+
+  // Ensure that the scene will be presented eventually, even if it is
+  // not associated with any renderer.  Note that this is only a backstop
+  // in case the scene does not get presented sooner as part of snapshotting
+  // a renderer.
+  MojoTimeTicks now = MojoGetTimeTicksNow();
+  DCHECK(now >= 0);
+  if (presentation_time <= now) {
+    SceneDef::Disposition disposition = PresentScene(scene_state, now);
+    if (disposition == SceneDef::Disposition::kFailed)
+      DestroyScene(scene_state);
+  } else {
+    base::MessageLoop::current()->PostDelayedTask(
+        FROM_HERE, base::Bind(&CompositorEngine::OnPresentScene,
+                              weak_factory_.GetWeakPtr(),
+                              scene_state->GetWeakPtr(), presentation_time),
+        base::TimeDelta::FromMicroseconds(presentation_time - now));

[abarth, 2016/01/10 22:55:35]

Do we need to schedule this for earlier so that it will actually be presented at
presentation_time?

[jeffbrown, 2016/01/16 03:28:32]

It actually doesn't matter here.  This only happens if the scene isn't part of a
visible scene graph as otherwise it would get snapshotted earlier.  I'll add a
comment.

+  }
+}
+
+void CompositorEngine::ScheduleFrame(SceneState* scene_state,
+                                     const SceneFrameCallback& callback) {
+  DCHECK(IsSceneStateRegisteredDebug(scene_state));
+
+  scene_state->AddSceneFrameCallback(callback);
+
+  // TODO(jeffbrown): Be more selective and do this work only for scenes
+  // which are strongly associated with the renderer so it doesn't receive
+  // conflicting timing signals coming from multiple renderers.
+  for (auto& renderer : renderers_) {
+    ScheduleFrameForRenderer(renderer, SchedulingMode::kUpdateAndSnapshot);
+  }
+}
+
+void CompositorEngine::SetRootScene(
+    RendererState* renderer_state,
+    mojo::gfx::composition::SceneTokenPtr scene_token,
+    uint32 scene_version,
+    mojo::RectPtr viewport) {
+  DCHECK(IsRendererStateRegisteredDebug(renderer_state));
+  DCHECK(scene_token);
+  DCHECK(viewport);
+  DVLOG(1) << "SetRootScene: renderer=" << renderer_state
+           << ", scene_token=" << scene_token
+           << ", scene_version=" << scene_version << ", viewport=" << viewport;
+
+  if (viewport->width < 1 || viewport->width > kMaxViewportWidth ||
+      viewport->height < 1 || viewport->height > kMaxViewportHeight) {

[abarth, 2016/01/10 22:55:35]

nit: I would have tested <= 0

[jeffbrown, 2016/01/16 03:28:31]

Done.

+    LOG(ERROR) << "Invalid viewport size: " << viewport;
+    DestroyRenderer(renderer_state);
+    return;
+  }
+
+  // Find the scene.
+  SceneState* scene_state = FindScene(scene_token->value);
+  if (!scene_state) {
+    LOG(ERROR) << "Could not set the renderer's root scene, scene not found: "
+                  "scene_token="
+               << scene_token;
+    DestroyRenderer(renderer_state);
+    return;
+  }
+
+  // Update the root.
+  if (renderer_state->SetRootScene(scene_state, scene_version, *viewport)) {
+    ScheduleFrameForRenderer(renderer_state, SchedulingMode::kSnapshot);
+  }
+}
+
+void CompositorEngine::HitTest(
+    RendererState* renderer_state,
+    mojo::PointPtr point,
+    const mojo::gfx::composition::HitTester::HitTestCallback& callback) {
+  DCHECK(IsRendererStateRegisteredDebug(renderer_state));
+  DCHECK(point);
+  DVLOG(1) << "HitTest: renderer=" << renderer_state << ", point=" << point;
+
+  if (renderer_state->frame()) {
+    callback.Run(
+        renderer_state->frame()->HitTest(SkPoint::Make(point->x, point->y)));
+  } else {
+    callback.Run(nullptr);

[abarth, 2016/01/10 22:55:35]

It's odd that there are two "failed" results here: a null HitTestResult and a
HitTestResult with an empty hits list.  Might want to reduce to just the latter.

[jeffbrown, 2016/01/16 03:28:32]

Good point.

+  }
+}
+
+SceneDef* CompositorEngine::ResolveSceneReference(
+    mojo::gfx::composition::SceneToken* scene_token) {
+  SceneState* scene_state = FindScene(scene_token->value);
+  return scene_state ? scene_state->scene_def() : nullptr;
+}
+
+void CompositorEngine::SendResourceUnavailable(SceneState* scene_state,
+                                               uint32_t resource_id) {
+  DCHECK(IsSceneStateRegisteredDebug(scene_state));
+  DVLOG(2) << "SendResourceUnavailable: resource_id=" << resource_id;
+
+  // TODO: Detect ANRs

[abarth, 2016/01/10 22:55:35]

ANRs?

[jeffbrown, 2016/01/16 03:28:31]

"Application Not Responding"

+  if (scene_state->scene_listener())

[abarth, 2016/01/10 22:55:35]

Multiline ifs require { }

[jeffbrown, 2016/01/16 03:28:32]

Done.

+    scene_state->scene_listener()->OnResourceUnavailable(
+        resource_id, base::Bind(&base::DoNothing));
+}
+
+SceneState* CompositorEngine::FindScene(uint32_t scene_token) {
+  auto it = scenes_by_token_.find(scene_token);
+  return it != scenes_by_token_.end() ? it->second : nullptr;
+}
+
+void CompositorEngine::InvalidateScene(SceneState* scene_state) {
+  DCHECK(IsSceneStateRegisteredDebug(scene_state));
+  DVLOG(2) << "InvalidateScene: scene=" << scene_state;
+
+  for (auto& renderer : renderers_) {
+    if (renderer->snapshot() &&
+        renderer->snapshot()->InvalidateScene(scene_state->scene_def())) {
+      ScheduleFrameForRenderer(renderer, SchedulingMode::kSnapshot);
+    }
+  }
+}
+
+SceneDef::Disposition CompositorEngine::PresentScene(
+    SceneState* scene_state,
+    int64_t presentation_time) {
+  DCHECK(IsSceneStateRegisteredDebug(scene_state));
+  DVLOG(2) << "PresentScene: scene=" << scene_state;
+
+  std::ostringstream errs;
+  SceneDef::Disposition disposition = scene_state->scene_def()->Present(
+      presentation_time, base::Bind(&CompositorEngine::ResolveSceneReference,
+                                    base::Unretained(this)),
+      base::Bind(&CompositorEngine::SendResourceUnavailable,
+                 base::Unretained(this), base::Unretained(scene_state)),
+      errs);
+  if (disposition == SceneDef::Disposition::kFailed) {
+    LOG(ERROR) << "Scene published invalid updates: scene=" << scene_state;
+    LOG(ERROR) << errs.str();
+    // Caller is responsible for destroying the scene.
+  }
+  return disposition;
+}
+
+void CompositorEngine::PresentRenderer(RendererState* renderer_state,
+                                       int64_t presentation_time) {
+  DCHECK(IsRendererStateRegisteredDebug(renderer_state));
+  DVLOG(2) << "PresentRenderer: renderer_state=" << renderer_state;
+
+  // TODO(jeffbrown): Be more selective and do this work only for scenes
+  // associated with the renderer that actually have pending updates.
+  std::vector<SceneState*> dead_scenes;
+  for (auto& pair : scenes_by_token_) {
+    SceneState* scene_state = pair.second;
+    SceneDef::Disposition disposition =
+        PresentScene(scene_state, presentation_time);
+    if (disposition == SceneDef::Disposition::kFailed)
+      dead_scenes.push_back(scene_state);
+  }
+  for (SceneState* scene_state : dead_scenes)
+    DestroyScene(scene_state);

[abarth, 2016/01/10 22:55:35]

Should we DCHECK that scene_state isn't in scenes_by_token_ anymore?

[jeffbrown, 2016/01/16 03:28:32]

You mean after DestroyScene returns?  I don't think that's necessary since this
function doesn't really care after this point.

+}
+
+void CompositorEngine::SnapshotRenderer(
+    RendererState* renderer_state,
+    const mojo::gfx::composition::FrameInfo& frame_info) {
+  DCHECK(IsRendererStateRegisteredDebug(renderer_state));
+  DVLOG(2) << "SnapshotRenderer: renderer_state=" << renderer_state;
+
+  if (VLOG_IS_ON(2)) {
+    std::ostringstream block_log;
+    SnapshotRendererInner(renderer_state, frame_info, &block_log);
+    if (!renderer_state->valid()) {
+      DVLOG(2) << "Rendering completely blocked: " << block_log.str();
+    } else if (!block_log.str().empty()) {
+      DVLOG(2) << "Rendering partially blocked: " << block_log.str();
+    } else {
+      DVLOG(2) << "Rendering unblocked";
+    }
+  } else {
+    SnapshotRendererInner(renderer_state, frame_info, nullptr);
+  }
+}
+
+void CompositorEngine::SnapshotRendererInner(
+    RendererState* renderer_state,
+    const mojo::gfx::composition::FrameInfo& frame_info,
+    std::ostream* block_log) {
+  if (!renderer_state->root_scene()) {
+    if (block_log)
+      *block_log << "No root scene" << std::endl;
+    renderer_state->SetSnapshot(nullptr);
+    return;
+  }
+
+  SnapshotBuilder builder(block_log);
+  renderer_state->SetSnapshot(
+      builder.Build(renderer_state->root_scene()->scene_def(),
+                    renderer_state->root_scene_viewport(), frame_info));
+
+  if (renderer_state->valid())
+    renderer_state->output()->SubmitFrame(renderer_state->frame());
+}
+
+void CompositorEngine::ScheduleFrameForRenderer(
+    RendererState* renderer_state,
+    SchedulingMode scheduling_mode) {
+  DCHECK(IsRendererStateRegisteredDebug(renderer_state));
+  renderer_state->output()->scheduler()->ScheduleFrame(scheduling_mode);
+}
+
+void CompositorEngine::OnOutputError(
+    const base::WeakPtr<RendererState>& renderer_state_weak) {
+  RendererState* renderer_state = renderer_state_weak.get();
+  if (!renderer_state)
+    return;
+  DCHECK(IsRendererStateRegisteredDebug(renderer_state));
+
+  LOG(ERROR) << "Renderer encountered a fatal error: renderer="
+             << renderer_state;
+
+  DestroyRenderer(renderer_state);
+}
+
+void CompositorEngine::OnOutputUpdateRequest(
+    const base::WeakPtr<RendererState>& renderer_state_weak,
+    const mojo::gfx::composition::FrameInfo& frame_info) {
+  RendererState* renderer_state = renderer_state_weak.get();
+  if (!renderer_state)
+    return;
+  DCHECK(IsRendererStateRegisteredDebug(renderer_state));
+
+  // TODO(jeffbrown): Be more selective and do this work only for scenes
+  // associated with the renderer.
+  for (auto& pair : scenes_by_token_) {
+    pair.second->DispatchSceneFrameCallbacks(frame_info);
+  }
+}
+
+void CompositorEngine::OnOutputSnapshotRequest(
+    const base::WeakPtr<RendererState>& renderer_state_weak,
+    const mojo::gfx::composition::FrameInfo& frame_info) {
+  RendererState* renderer_state = renderer_state_weak.get();
+  if (!renderer_state)
+    return;
+  DCHECK(IsRendererStateRegisteredDebug(renderer_state));
+
+  PresentRenderer(renderer_state, frame_info.presentation_time);
+  SnapshotRenderer(renderer_state, frame_info);
+}
+
+void CompositorEngine::OnPresentScene(
+    const base::WeakPtr<SceneState>& scene_state_weak,
+    int64_t presentation_time) {
+  SceneState* scene_state = scene_state_weak.get();
+  if (!scene_state)
+    return;
+  DCHECK(IsSceneStateRegisteredDebug(scene_state));
+
+  SceneDef::Disposition disposition =
+      PresentScene(scene_state, presentation_time);
+  if (disposition == SceneDef::Disposition::kFailed)
+    DestroyScene(scene_state);
+  else if (disposition == SceneDef::Disposition::kSucceeded)
+    InvalidateScene(scene_state);
+}
+
+}  // namespace compositor