Mac overlays: Isolate partial swap support

content/common/gpu/image_transport_surface_overlay_mac.mm

 // 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 "content/common/gpu/image_transport_surface_overlay_mac.h"
 
 #include <CoreGraphics/CoreGraphics.h>
 #include <IOSurface/IOSurface.h>
 #include <OpenGL/CGLRenderers.h>
 #include <OpenGL/CGLTypes.h>
@@ skipping 76 matching lines @@
 
 namespace content {
 
 scoped_refptr<gfx::GLSurface> ImageTransportSurfaceCreateNativeSurface(
     GpuChannelManager* manager,
     GpuCommandBufferStub* stub,
     gfx::PluginWindowHandle handle) {
   return new ImageTransportSurfaceOverlayMac(manager, stub, handle);
 }
 
-class ImageTransportSurfaceOverlayMac::OverlayPlane {
+class CALayerPartialDamageTree {
+ public:
+  CALayerPartialDamageTree(bool allow_partial_swap,
+                           base::ScopedCFTypeRef<IOSurfaceRef> io_surface,
+                           const gfx::Rect& pixel_frame_rect);
+  ~CALayerPartialDamageTree();
+
+  base::ScopedCFTypeRef<IOSurfaceRef> RootLayerIOSurface();
+  void CommitCALayers(CALayer* superlayer,
+                      scoped_ptr<CALayerPartialDamageTree> old_tree,
+                      float scale_factor,
+                      const gfx::Rect& pixel_damage_rect);
+
+ private:
+  class OverlayPlane;
+
+  void UpdateRootAndPartialDamagePlanes(CALayerPartialDamageTree* old_tree,
+                                        const gfx::RectF& pixel_damage_rect);
+  void UpdateRootAndPartialDamageCALayers(CALayer* superlayer,
+                                          float scale_factor);
+
+  const bool allow_partial_swap_;
+  linked_ptr<OverlayPlane> root_plane_;
+  std::list<linked_ptr<OverlayPlane>> partial_damage_planes_;
+};
+
+class CALayerPartialDamageTree::OverlayPlane {
  public:
   static linked_ptr<OverlayPlane> CreateWithFrameRect(
       int z_order,
       base::ScopedCFTypeRef<IOSurfaceRef> io_surface,
       const gfx::RectF& pixel_frame_rect,
       const gfx::RectF& contents_rect) {
     gfx::Transform transform;
     transform.Translate(pixel_frame_rect.x(), pixel_frame_rect.y());
     return linked_ptr<OverlayPlane>(
         new OverlayPlane(z_order, io_surface, contents_rect, pixel_frame_rect));
@@ skipping 70 matching lines @@
 
 class ImageTransportSurfaceOverlayMac::PendingSwap {
  public:
   PendingSwap() {}
   ~PendingSwap() { DCHECK(!gl_fence); }
 
   gfx::Size pixel_size;
   float scale_factor;
   gfx::Rect pixel_damage_rect;
 
-  linked_ptr<OverlayPlane> root_plane;
+  scoped_ptr<CALayerPartialDamageTree> partial_damage_tree;
   scoped_ptr<CALayerTree> ca_layer_tree;
   std::vector<ui::LatencyInfo> latency_info;
 
   // A fence object, and the CGL context it was issued in.
   base::ScopedTypeRef<CGLContextObj> cgl_context;
   scoped_ptr<gfx::GLFence> gl_fence;
 
   // The earliest time that this frame may be drawn. A frame is not allowed
   // to draw until a fraction of the way through the vsync interval after its
   // This extra latency is to allow wiggle-room for smoothness.
   base::TimeTicks earliest_display_time_allowed;
 
   // The time that this will wake up and draw, if a following swap does not
   // cause it to draw earlier.
   base::TimeTicks target_display_time;
 };
 
 ImageTransportSurfaceOverlayMac::ImageTransportSurfaceOverlayMac(
     GpuChannelManager* manager,
     GpuCommandBufferStub* stub,
     gfx::PluginWindowHandle handle)
     : use_remote_layer_api_(ui::RemoteLayerAPISupported()),
       scale_factor_(1),
       gl_renderer_id_(0),
       vsync_parameters_valid_(false),
-      next_ca_layer_z_order_(1),
       display_pending_swap_timer_(true, false),
       weak_factory_(this) {
   helper_.reset(new ImageTransportHelper(this, manager, stub, handle));
   ui::GpuSwitchingManager::GetInstance()->AddObserver(this);
 }
 
 ImageTransportSurfaceOverlayMac::~ImageTransportSurfaceOverlayMac() {
   ui::GpuSwitchingManager::GetInstance()->RemoveObserver(this);
   Destroy();
 }
@@ skipping 12 matching lines @@
     ca_root_layer_.reset([[CALayer alloc] init]);
     [ca_root_layer_ setGeometryFlipped:YES];
     [ca_root_layer_ setOpaque:YES];
     [ca_context_ setLayer:ca_root_layer_];
   }
   return true;
 }
 
 void ImageTransportSurfaceOverlayMac::Destroy() {
   DisplayAndClearAllPendingSwaps();
-  current_partial_damage_planes_.clear();
-  current_root_plane_.reset();
+
+  current_partial_damage_tree_.reset();
+  current_ca_layer_tree_.reset();
 }
 
 bool ImageTransportSurfaceOverlayMac::IsOffscreen() {
   return false;
 }
 
 gfx::SwapResult ImageTransportSurfaceOverlayMac::SwapBuffersInternal(
     const gfx::Rect& pixel_damage_rect) {
   TRACE_EVENT0("gpu", "ImageTransportSurfaceOverlayMac::SwapBuffersInternal");
-  next_ca_layer_z_order_ = 1;
 
   // Use the same concept of 'now' for the entire function. The duration of
   // this function only affect the result if this function lasts across a vsync
   // boundary, in which case smooth animation is out the window anyway.
   const base::TimeTicks now = base::TimeTicks::Now();
 
   // Decide if the frame should be drawn immediately, or if we should wait until
   // its work finishes before drawing immediately.
   bool display_immediately = false;
   if (vsync_parameters_valid_ &&
@@ skipping 10 matching lines @@
     if (IsFirstPendingSwapReadyToDisplay(now))
       DisplayFirstPendingSwapImmediately();
   }
 
   // The remainder of the function will populate the PendingSwap structure and
   // then enqueue it.
   linked_ptr<PendingSwap> new_swap(new PendingSwap);
   new_swap->pixel_size = pixel_size_;
   new_swap->scale_factor = scale_factor_;
   new_swap->pixel_damage_rect = pixel_damage_rect;
-  new_swap->root_plane = pending_root_plane_;
-  pending_root_plane_ = linked_ptr<OverlayPlane>();
+  new_swap->partial_damage_tree.swap(pending_partial_damage_tree_);
   new_swap->ca_layer_tree.swap(pending_ca_layer_tree_);
   new_swap->latency_info.swap(latency_info_);
 
   // A flush is required to ensure that all content appears in the layer.
   {
     gfx::ScopedSetGLToRealGLApi scoped_set_gl_api;
     TRACE_EVENT0("gpu", "ImageTransportSurfaceOverlayMac::glFlush");
     CheckGLErrors("before flushing frame");
     new_swap->cgl_context.reset(CGLGetCurrentContext(),
                                 base::scoped_policy::RETAIN);
@@ skipping 59 matching lines @@
   // If there is a fence for this object, delete it.
   if (swap->gl_fence) {
     gfx::ScopedSetGLToRealGLApi scoped_set_gl_api;
     gfx::ScopedCGLSetCurrentContext scoped_set_current(swap->cgl_context);
 
     CheckGLErrors("before deleting active fence");
     swap->gl_fence.reset();
     CheckGLErrors("while deleting active fence");
   }
 
-  // Update the plane lists.
+  // Update the CALayer hierarchy.
   {
-    // Sort the input planes by z-index, and remove any overlays from the
-    // damage rect.
     gfx::RectF pixel_damage_rect = gfx::RectF(swap->pixel_damage_rect);
     ScopedCAActionDisabler disabler;
-    UpdateRootAndPartialDamagePlanes(swap->root_plane, pixel_damage_rect);
-    UpdateRootAndPartialDamageCALayers(swap->scale_factor);
-    UpdateCALayerTree(std::move(swap->ca_layer_tree), swap->scale_factor);
+    if (swap->ca_layer_tree) {
+      swap->ca_layer_tree->CommitScheduledCALayers(
+          ca_root_layer_.get(), std::move(current_ca_layer_tree_),
+          swap->scale_factor);
+      current_ca_layer_tree_.swap(swap->ca_layer_tree);
+      current_partial_damage_tree_.reset();
+    } else if (swap->partial_damage_tree) {
+      swap->partial_damage_tree->CommitCALayers(
+          ca_root_layer_.get(), std::move(current_partial_damage_tree_),
+          swap->scale_factor, swap->pixel_damage_rect);
+      current_partial_damage_tree_.swap(swap->partial_damage_tree);
+      current_ca_layer_tree_.reset();
+    } else {
+      [ca_root_layer_ setSublayers:nil];
+    }
+    swap->ca_layer_tree.reset();
+    swap->partial_damage_tree.reset();
   }
 
   // Update the latency info to reflect the swap time.
   base::TimeTicks swap_time = base::TimeTicks::Now();
   for (auto latency_info : swap->latency_info) {
     latency_info.AddLatencyNumberWithTimestamp(
         ui::INPUT_EVENT_GPU_SWAP_BUFFER_COMPONENT, 0, 0, swap_time, 1);
     latency_info.AddLatencyNumberWithTimestamp(
         ui::INPUT_EVENT_LATENCY_TERMINATED_FRAME_SWAP_COMPONENT, 0, 0,
         swap_time, 1);
   }
 
   // Send acknowledgement to the browser.
   GpuHostMsg_AcceleratedSurfaceBuffersSwapped_Params params;
   if (use_remote_layer_api_) {
     params.ca_context_id = [ca_context_ contextId];
-  } else if (current_root_plane_.get()) {
-    params.io_surface.reset(
-        IOSurfaceCreateMachPort(current_root_plane_->io_surface));
+  } else if (current_partial_damage_tree_) {
+    params.io_surface.reset(IOSurfaceCreateMachPort(
+        current_partial_damage_tree_->RootLayerIOSurface()));
   }
   params.size = swap->pixel_size;
   params.scale_factor = swap->scale_factor;
   params.latency_info.swap(swap->latency_info);
   helper_->SendAcceleratedSurfaceBuffersSwapped(params);
 
   // Remove this from the queue, and reset any callback timers.
   pending_swaps_.pop_front();
 }
 
-void ImageTransportSurfaceOverlayMac::UpdateRootAndPartialDamagePlanes(
-    const linked_ptr<OverlayPlane>& new_root_plane,
+void CALayerPartialDamageTree::UpdateRootAndPartialDamagePlanes(
+    CALayerPartialDamageTree* old_tree,
     const gfx::RectF& pixel_damage_rect) {
-  std::list<linked_ptr<OverlayPlane>> old_partial_damage_planes;
-  old_partial_damage_planes.swap(current_partial_damage_planes_);
+  // This is the plane that will be updated this frame. It may be the root plane
+  // or a child plane.
   linked_ptr<OverlayPlane> plane_for_swap;
 
-  // If there is no new root plane, remove everything.
-  if (!new_root_plane.get()) {
-    old_partial_damage_planes.clear();
-    current_root_plane_.reset();
-    return;
-  }
-
   // If the frame's size changed, if we haven't updated the root layer, if
   // we have full damage, or if we don't support remote layers, then use the
   // root layer directly.
-  if (!use_remote_layer_api_ || !current_root_plane_.get() ||
-      current_root_plane_->pixel_frame_rect !=
-          new_root_plane->pixel_frame_rect ||
-      pixel_damage_rect == new_root_plane->pixel_frame_rect) {
-    plane_for_swap = new_root_plane;
+  if (!allow_partial_swap_ || !old_tree ||
+      old_tree->root_plane_->pixel_frame_rect !=
+          root_plane_->pixel_frame_rect ||
+      pixel_damage_rect == root_plane_->pixel_frame_rect) {
+    plane_for_swap = root_plane_;
   }
 
-  // Walk though the existing partial damage layers and see if there is one that
-  // is appropriate to re-use.
+  // Walk though the old tree's partial damage layers and see if there is one
+  // that is appropriate to re-use.
   if (!plane_for_swap.get() && !pixel_damage_rect.IsEmpty()) {
     gfx::RectF plane_to_reuse_dip_enlarged_rect;
 
     // Find the last partial damage plane to re-use the CALayer from. Grow the
     // new rect for this layer to include this damage, and all nearby partial
     // damage layers.
     linked_ptr<OverlayPlane> plane_to_reuse;
-    for (auto& old_plane : old_partial_damage_planes) {
+    for (auto& old_plane : old_tree->partial_damage_planes_) {
       gfx::RectF dip_enlarged_rect = old_plane->pixel_frame_rect;
       dip_enlarged_rect.Union(pixel_damage_rect);
 
       // Compute the fraction of the pixels that would not be updated by this
       // swap. If it is too big, try another layer.
       float waste_fraction = dip_enlarged_rect.size().GetArea() * 1.f /
                              pixel_damage_rect.size().GetArea();
       if (waste_fraction > kMaximumPartialDamageWasteFraction)
         continue;
 
       plane_to_reuse = old_plane;
       plane_to_reuse_dip_enlarged_rect.Union(dip_enlarged_rect);
     }
 
     if (plane_to_reuse.get()) {
       gfx::RectF enlarged_contents_rect = plane_to_reuse_dip_enlarged_rect;
-      enlarged_contents_rect.Scale(
-          1. / new_root_plane->pixel_frame_rect.width(),
-          1. / new_root_plane->pixel_frame_rect.height());
+      enlarged_contents_rect.Scale(1. / root_plane_->pixel_frame_rect.width(),
+                                   1. / root_plane_->pixel_frame_rect.height());
 
       plane_for_swap = OverlayPlane::CreateWithFrameRect(
-          0, new_root_plane->io_surface, plane_to_reuse_dip_enlarged_rect,
+          0, root_plane_->io_surface, plane_to_reuse_dip_enlarged_rect,
           enlarged_contents_rect);
 
       plane_for_swap->TakeCALayerFrom(plane_to_reuse.get());
-      if (plane_to_reuse != old_partial_damage_planes.back())
+      if (plane_to_reuse != old_tree->partial_damage_planes_.back())
         [plane_for_swap->ca_layer removeFromSuperlayer];
     }
   }
 
   // If we haven't found an appropriate layer to re-use, create a new one, if
   // we haven't already created too many.
   if (!plane_for_swap.get() && !pixel_damage_rect.IsEmpty() &&
-      old_partial_damage_planes.size() < kMaximumPartialDamageLayers) {
+      old_tree->partial_damage_planes_.size() < kMaximumPartialDamageLayers) {
     gfx::RectF contents_rect = gfx::RectF(pixel_damage_rect);
-    contents_rect.Scale(1. / new_root_plane->pixel_frame_rect.width(),
-                        1. / new_root_plane->pixel_frame_rect.height());
+    contents_rect.Scale(1. / root_plane_->pixel_frame_rect.width(),
+                        1. / root_plane_->pixel_frame_rect.height());
     plane_for_swap = OverlayPlane::CreateWithFrameRect(
-        0, new_root_plane->io_surface, pixel_damage_rect, contents_rect);
+        0, root_plane_->io_surface, pixel_damage_rect, contents_rect);
   }
 
   // And if we still don't have a layer, use the root layer.
   if (!plane_for_swap.get() && !pixel_damage_rect.IsEmpty())
-    plane_for_swap = new_root_plane;
+    plane_for_swap = root_plane_;
 
   // Walk all old partial damage planes. Remove anything that is now completely
-  // covered, and move everything else into the new
-  // |current_partial_damage_planes_|.
-  for (auto& old_plane : old_partial_damage_planes) {
-    // Intersect the planes' frames with the new root plane to ensure that
-    // they don't get kept alive inappropriately.
-    gfx::RectF old_plane_frame_rect = old_plane->pixel_frame_rect;
-    old_plane_frame_rect.Intersect(new_root_plane->pixel_frame_rect);
+  // covered, and move everything else into the new |partial_damage_planes_|.
+  if (old_tree) {
+    for (auto& old_plane : old_tree->partial_damage_planes_) {
+      // Intersect the planes' frames with the new root plane to ensure that
+      // they don't get kept alive inappropriately.
+      gfx::RectF old_plane_frame_rect = old_plane->pixel_frame_rect;
+      old_plane_frame_rect.Intersect(root_plane_->pixel_frame_rect);
 
-    bool old_plane_covered_by_swap = false;
-    if (plane_for_swap.get() &&
-        plane_for_swap->pixel_frame_rect.Contains(old_plane_frame_rect)) {
-      old_plane_covered_by_swap = true;
+      bool old_plane_covered_by_swap = false;
+      if (plane_for_swap.get() &&
+          plane_for_swap->pixel_frame_rect.Contains(old_plane_frame_rect)) {
+        old_plane_covered_by_swap = true;
+      }
+      if (!old_plane_covered_by_swap) {
+        DCHECK(old_plane->ca_layer);
+        partial_damage_planes_.push_back(old_plane);
+      }
     }
-    if (!old_plane_covered_by_swap) {
-      DCHECK(old_plane->ca_layer);
-      current_partial_damage_planes_.push_back(old_plane);
-    }
+    if (plane_for_swap != root_plane_)
+      root_plane_ = old_tree->root_plane_;
   }
 
   // Finally, add the new swap's plane at the back of the list, if it exists.
-  if (plane_for_swap == new_root_plane) {
-    current_root_plane_ = new_root_plane;
-  } else if (plane_for_swap.get()) {
-    current_partial_damage_planes_.push_back(plane_for_swap);
+  if (plane_for_swap.get() && plane_for_swap != root_plane_) {
+    partial_damage_planes_.push_back(plane_for_swap);
   }
 }
 
-void ImageTransportSurfaceOverlayMac::UpdateRootAndPartialDamageCALayers(
+void CALayerPartialDamageTree::UpdateRootAndPartialDamageCALayers(
+    CALayer* superlayer,
     float scale_factor) {
-  if (!use_remote_layer_api_) {
-    DCHECK(current_partial_damage_planes_.empty());
+  if (!allow_partial_swap_) {
+    DCHECK(partial_damage_planes_.empty());
     return;
   }
 
   // Allocate and update CALayers for the backbuffer and partial damage layers.
-  if (current_root_plane_.get()) {
-    if (!current_root_plane_->ca_layer) {
-      current_root_plane_->ca_layer.reset([[CALayer alloc] init]);
-      [ca_root_layer_ setSublayers:nil];
-      [ca_root_layer_ addSublayer:current_root_plane_->ca_layer];
-    }
+  if (!root_plane_->ca_layer) {
+    root_plane_->ca_layer.reset([[CALayer alloc] init]);
+    [superlayer setSublayers:nil];
+    [superlayer addSublayer:root_plane_->ca_layer];
   }
-  for (auto& plane : current_partial_damage_planes_) {
+  for (auto& plane : partial_damage_planes_) {
     if (!plane->ca_layer) {
-      DCHECK(plane == current_partial_damage_planes_.back());
+      DCHECK(plane == partial_damage_planes_.back());
       plane->ca_layer.reset([[CALayer alloc] init]);
     }
     if (![plane->ca_layer superlayer]) {
-      DCHECK(plane == current_partial_damage_planes_.back());
-      [ca_root_layer_ addSublayer:plane->ca_layer];
+      DCHECK(plane == partial_damage_planes_.back());
+      [superlayer addSublayer:plane->ca_layer];
     }
   }
-  if (current_root_plane_.get())
-    current_root_plane_->UpdateProperties(scale_factor);
-  for (auto& plane : current_partial_damage_planes_)
+  root_plane_->UpdateProperties(scale_factor);
+  for (auto& plane : partial_damage_planes_)
     plane->UpdateProperties(scale_factor);
 }
 
-void ImageTransportSurfaceOverlayMac::UpdateCALayerTree(
-    scoped_ptr<CALayerTree> ca_layer_tree,
-    float scale_factor) {
-  if (ca_layer_tree) {
-    ca_layer_tree->CommitScheduledCALayers(
-        ca_root_layer_.get(), std::move(current_ca_layer_tree_), scale_factor);
-    current_ca_layer_tree_.swap(ca_layer_tree);
-    ca_layer_tree.reset();
-  } else {
-    current_ca_layer_tree_.reset();
-  }
-}
-
 void ImageTransportSurfaceOverlayMac::DisplayAndClearAllPendingSwaps() {
   TRACE_EVENT0("gpu",
       "ImageTransportSurfaceOverlayMac::DisplayAndClearAllPendingSwaps");
   while (!pending_swaps_.empty())
     DisplayFirstPendingSwapImmediately();
 }
 
 void ImageTransportSurfaceOverlayMac::CheckPendingSwapsCallback() {
   TRACE_EVENT0("gpu",
       "ImageTransportSurfaceOverlayMac::CheckPendingSwapsCallback");
@@ skipping 70 matching lines @@
     const gfx::Rect& pixel_frame_rect,
     const gfx::RectF& crop_rect) {
   if (transform != gfx::OVERLAY_TRANSFORM_NONE) {
     DLOG(ERROR) << "Invalid overlay plane transform.";
     return false;
   }
   if (z_order) {
     DLOG(ERROR) << "Invalid non-zero Z order.";
     return false;
   }
-
-  pending_root_plane_ = OverlayPlane::CreateWithFrameRect(
-      z_order, static_cast<gl::GLImageIOSurface*>(image)->io_surface(),
-      gfx::RectF(pixel_frame_rect), crop_rect);
+  if (pending_partial_damage_tree_) {
+    DLOG(ERROR) << "Only one overlay per swap is allowed.";
+    return false;
+  }
+  pending_partial_damage_tree_.reset(new CALayerPartialDamageTree(
+      use_remote_layer_api_,
+      static_cast<gl::GLImageIOSurface*>(image)->io_surface(),
+      pixel_frame_rect));
   return true;
 }
 
 bool ImageTransportSurfaceOverlayMac::ScheduleCALayer(
     gl::GLImage* contents_image,
     const gfx::RectF& contents_rect,
     float opacity,
     unsigned background_color,
     unsigned edge_aa_mask,
     const gfx::RectF& rect,
@@ skipping 77 matching lines @@
 
   // Compute the previous vsync time.
   base::TimeTicks previous_vsync =
       vsync_interval_ * ((from - vsync_timebase_) / vsync_interval_) +
       vsync_timebase_;
 
   // Return |interval_fraction| through the next vsync.
   return previous_vsync + (1 + interval_fraction) * vsync_interval_;
 }
 
+CALayerPartialDamageTree::CALayerPartialDamageTree(
+    bool allow_partial_swap,
+    base::ScopedCFTypeRef<IOSurfaceRef> io_surface,
+    const gfx::Rect& pixel_frame_rect)
+    : allow_partial_swap_(allow_partial_swap) {
+  root_plane_ = OverlayPlane::CreateWithFrameRect(
+      0, io_surface, gfx::RectF(pixel_frame_rect), gfx::RectF(0, 0, 1, 1));
+}
+
+CALayerPartialDamageTree::~CALayerPartialDamageTree() {}
+
+base::ScopedCFTypeRef<IOSurfaceRef>
+CALayerPartialDamageTree::RootLayerIOSurface() {
+  return root_plane_->io_surface;
+}
+
+void CALayerPartialDamageTree::CommitCALayers(
+    CALayer* superlayer,
+    scoped_ptr<CALayerPartialDamageTree> old_tree,
+    float scale_factor,
+    const gfx::Rect& pixel_damage_rect) {
+  UpdateRootAndPartialDamagePlanes(old_tree.get(),
+                                   gfx::RectF(pixel_damage_rect));
+  UpdateRootAndPartialDamageCALayers(superlayer, scale_factor);
+}
+
 }  // namespace content