WIP: Surface Synchronization System

cc/surfaces/surface.cc

Index: cc/surfaces/surface.cc
diff --git a/cc/surfaces/surface.cc b/cc/surfaces/surface.cc
index 20d34011a58d5aa0bff6e4236856476a219fe560..e7b809fc9e4448726aa08dce1f126b3c6e69db3c 100644
--- a/cc/surfaces/surface.cc
+++ b/cc/surfaces/surface.cc
@@ -12,6 +12,7 @@
 #include "cc/base/container_util.h"
 #include "cc/output/compositor_frame.h"
 #include "cc/output/copy_output_request.h"
+#include "cc/surfaces/pending_surface_observer.h"
 #include "cc/surfaces/surface_factory.h"
 #include "cc/surfaces/surface_id_allocator.h"
 #include "cc/surfaces/surface_manager.h"
@@ -31,11 +32,15 @@ Surface::Surface(const SurfaceId& id, base::WeakPtr<SurfaceFactory> factory)
 
 Surface::~Surface() {
   ClearCopyRequests();
-  if (current_frame_ && factory_) {
-    UnrefFrameResources(*current_frame_);
+  if (active_frame_ && factory_) {
+    UnrefFrameResources(*active_frame_);
   }
   if (!draw_callback_.is_null())
     draw_callback_.Run();
+
+  for (auto& observer : observers_)
+    observer.OnSurfaceDiscarded(this);
+  observers_.Clear();
 }
 
 void Surface::SetPreviousFrameSurface(Surface* surface) {
@@ -45,46 +50,96 @@ void Surface::SetPreviousFrameSurface(Surface* surface) {
 }
 
 void Surface::QueueFrame(CompositorFrame frame, const DrawCallback& callback) {
-  DCHECK(factory_);
-  ClearCopyRequests();
+  base::Optional<CompositorFrame> previous_pending_frame =
+      std::move(pending_frame_);
+  pending_frame_.reset();
 
-  TakeLatencyInfo(&frame.metadata.latency_info);
+  std::set<SurfaceId> new_blocked_on_surfaces;
 
-  base::Optional<CompositorFrame> previous_frame = std::move(current_frame_);
-  current_frame_ = std::move(frame);
+  // Referenced surface IDs that aren't currently known to the surface manager
+  // block this frame.
+  for (const SurfaceId& surface_id : frame.metadata.referenced_surfaces) {
+    Surface* surface = factory_->manager()->GetSurfaceForId(surface_id);
+    if (!surface || !surface->HasFrame())
+      new_blocked_on_surfaces.insert(surface_id);
+  }
+
+  uint32_t added = 0;
+  uint32_t removed = 0;
+
+  if (previous_pending_frame.has_value()) {
+    SurfaceDependencies added_dependencies;
+    SurfaceDependencies removed_dependencies;
+
+    for (const SurfaceId& surface_id : blocked_on_surfaces_) {
+      if (!new_blocked_on_surfaces.count(surface_id))
+        removed_dependencies.insert(surface_id);
+    }
 
-  if (current_frame_) {
-    factory_->ReceiveFromChild(current_frame_->resource_list);
+    for (const SurfaceId& surface_id : new_blocked_on_surfaces) {
+      if (!blocked_on_surfaces_.count(surface_id)) {
+        added_dependencies.insert(surface_id);
+        fprintf(stderr, ">>>[%s] QueueFrame Blocked On: %s\n",
+                this->surface_id().ToString().c_str(),
+                surface_id.ToString().c_str());
+      }
+    }
+
+    added = added_dependencies.size();
+    removed = removed_dependencies.size();
+
+    if (!added_dependencies.empty() || !removed_dependencies.empty()) {
+      for (auto& observer : observers_) {
+        observer.OnSurfaceChanged(this, added_dependencies,
+                                  removed_dependencies);
+      }
+    }
   }
 
-  // Empty frames shouldn't be drawn and shouldn't contribute damage, so don't
-  // increment frame index for them.
-  if (current_frame_ && !current_frame_->render_pass_list.empty()) {
-    ++frame_index_;
+  blocked_on_surfaces_ = std::move(new_blocked_on_surfaces);
+  if (blocked_on_surfaces_.size() > 0) {
+    std::stringstream sstr;
+    sstr << "{" << std::endl;
+    for (const auto& surface_id : blocked_on_surfaces_) {
+      sstr << "   " << surface_id.ToString() << "\n";
+    }
+    sstr << "}" << std::endl;
+
+    fprintf(
+        stderr,
+        ">>>[%s] QueueFrame blocked_on_surfaces: %d added: %d removed: %d\n%s",
+        surface_id().ToString().c_str(), (uint32_t)blocked_on_surfaces_.size(),
+        added, removed, sstr.str().c_str());
   }
 
-  previous_frame_surface_id_ = surface_id();
+  if (!blocked_on_surfaces_.empty()) {
+    pending_frame_ = std::move(frame);
+    if (pending_frame_)
+      factory_->ReceiveFromChild(pending_frame_->resource_list);
+  } else {
+    fprintf(stderr, ">>>Surface::QueueFrame activating frame: %s\n",
+            surface_id().ToString().c_str());
+    ActivateFrame(std::move(frame));
+  }
 
-  if (previous_frame)
-    UnrefFrameResources(*previous_frame);
+  if (previous_pending_frame)
+    UnrefFrameResources(*previous_pending_frame);
 
   if (!draw_callback_.is_null())
     draw_callback_.Run();
   draw_callback_ = callback;
-
-  referenced_surfaces_ = current_frame_->metadata.referenced_surfaces;
 }
 
 void Surface::EvictFrame() {
   QueueFrame(CompositorFrame(), DrawCallback());
-  current_frame_.reset();
+  active_frame_.reset();
 }
 
 void Surface::RequestCopyOfOutput(
     std::unique_ptr<CopyOutputRequest> copy_request) {
-  if (current_frame_ && !current_frame_->render_pass_list.empty()) {
+  if (active_frame_ && !active_frame_->render_pass_list.empty()) {
     std::vector<std::unique_ptr<CopyOutputRequest>>& copy_requests =
-        current_frame_->render_pass_list.back()->copy_requests;
+        active_frame_->render_pass_list.back()->copy_requests;
 
     if (void* source = copy_request->source()) {
       // Remove existing CopyOutputRequests made on the Surface by the same
@@ -102,11 +157,87 @@ void Surface::RequestCopyOfOutput(
   }
 }
 
+void Surface::ReportSurfaceIdAvailable(const SurfaceId& surface_id) {
+  auto it = blocked_on_surfaces_.find(surface_id);
+  // This surface may no longer have blockers if the deadline has passed.
+  if (it == blocked_on_surfaces_.end())
+    return;
+
+  blocked_on_surfaces_.erase(it);
+  fprintf(stderr, ">>>[%s] %s available, %d remaining\n",
+          this->surface_id().ToString().c_str(), surface_id.ToString().c_str(),
+          (uint32_t)blocked_on_surfaces_.size());
+
+  if (!blocked_on_surfaces_.empty())
+    return;
+
+  // All blockers have been cleared. The surface can be activated now.
+  ActivatePendingFrame();
+}
+
+void Surface::AddObserver(PendingSurfaceObserver* observer) {
+  observers_.AddObserver(observer);
+}
+
+void Surface::RemoveObserver(PendingSurfaceObserver* observer) {
+  observers_.RemoveObserver(observer);
+}
+
+void Surface::ActivatePendingFrameForDeadline() {
+  if (!pending_frame_ || !pending_frame_->metadata.respect_deadline)
+    return;
+  std::stringstream sstr;
+  sstr << "Deadline for blockers: {" << std::endl;
+  for (const auto& surface_id : blocked_on_surfaces_) {
+    sstr << "   " << surface_id.ToString() << "\n";
+  }
+  sstr << "}" << std::endl;
+
+  fprintf(stderr, ">>>Surface::ActivatePendingFrameForDeadline: %s\n%s",
+          surface_id().ToString().c_str(), sstr.str().c_str());
+
+  blocked_on_surfaces_.clear();
+  ActivatePendingFrame();
+}
+
+void Surface::ActivatePendingFrame() {
+  ActivateFrame(std::move(pending_frame_.value()));
+  pending_frame_.reset();
+}
+
+void Surface::ActivateFrame(CompositorFrame frame) {
+  DCHECK(factory_);
+  ClearCopyRequests();
+
+  TakeLatencyInfo(&frame.metadata.latency_info);
+
+  base::Optional<CompositorFrame> previous_frame = std::move(active_frame_);
+  active_frame_ = std::move(frame);
+
+  if (active_frame_)
+    factory_->ReceiveFromChild(active_frame_->resource_list);
+
+  // Empty frames shouldn't be drawn and shouldn't contribute damage, so don't
+  // increment frame index for them.
+  if (active_frame_ && !active_frame_->render_pass_list.empty())
+    ++frame_index_;
+
+  previous_frame_surface_id_ = surface_id();
+
+  if (previous_frame)
+    UnrefFrameResources(*previous_frame);
+
+  referenced_surfaces_ = active_frame_->metadata.referenced_surfaces;
+
+  for (auto& observer : observers_)
+    observer.OnSurfaceActivated(this);
+}
+
 void Surface::TakeCopyOutputRequests(
     std::multimap<int, std::unique_ptr<CopyOutputRequest>>* copy_requests) {
   DCHECK(copy_requests->empty());
-  if (current_frame_) {
-    for (const auto& render_pass : current_frame_->render_pass_list) {
+  if (active_frame_) {
+    for (const auto& render_pass : active_frame_->render_pass_list) {
       for (auto& request : render_pass->copy_requests) {
         copy_requests->insert(
             std::make_pair(render_pass->id, std::move(request)));
@@ -117,21 +248,25 @@ void Surface::TakeCopyOutputRequests(
 }
 
 const CompositorFrame& Surface::GetEligibleFrame() const {
-  DCHECK(current_frame_);
-  return current_frame_.value();
+  DCHECK(active_frame_);
+  return active_frame_.value();
+}
+
+const base::Optional<CompositorFrame>& Surface::GetPendingFrame() {
+  return pending_frame_;
 }
 
 void Surface::TakeLatencyInfo(std::vector<ui::LatencyInfo>* latency_info) {
-  if (!current_frame_)
+  if (!active_frame_)
     return;
   if (latency_info->empty()) {
-    current_frame_->metadata.latency_info.swap(*latency_info);
+    active_frame_->metadata.latency_info.swap(*latency_info);
     return;
   }
-  std::copy(current_frame_->metadata.latency_info.begin(),
-            current_frame_->metadata.latency_info.end(),
+  std::copy(active_frame_->metadata.latency_info.begin(),
+            active_frame_->metadata.latency_info.end(),
             std::back_inserter(*latency_info));
-  current_frame_->metadata.latency_info.clear();
+  active_frame_->metadata.latency_info.clear();
 }
 
 void Surface::RunDrawCallbacks() {
@@ -169,8 +304,8 @@ void Surface::UnrefFrameResources(const CompositorFrame& frame) {
 }
 
 void Surface::ClearCopyRequests() {
-  if (current_frame_) {
-    for (const auto& render_pass : current_frame_->render_pass_list) {
+  if (active_frame_) {
+    for (const auto& render_pass : active_frame_->render_pass_list) {
       for (const auto& copy_request : render_pass->copy_requests)
         copy_request->SendEmptyResult();
     }