cc/surfaces/surface_aggregator.cc

   1 // Copyright 2014 The Chromium Authors. All rights reserved.
   2 // Use of this source code is governed by a BSD-style license that can be
   3 // found in the LICENSE file.
   4
   5 #include "cc/surfaces/surface_aggregator.h"
   6
   7 #include <map>
   8
   9 #include "base/bind.h"
  10 #include "base/containers/hash_tables.h"
  11 #include "base/logging.h"
  12 #include "base/trace_event/trace_event.h"
  13 #include "cc/base/math_util.h"
  14 #include "cc/output/compositor_frame.h"
  15 #include "cc/output/delegated_frame_data.h"
  16 #include "cc/quads/draw_quad.h"
  17 #include "cc/quads/render_pass_draw_quad.h"
  18 #include "cc/quads/shared_quad_state.h"
  19 #include "cc/quads/surface_draw_quad.h"
  20 #include "cc/surfaces/surface.h"
  21 #include "cc/surfaces/surface_factory.h"
  22 #include "cc/surfaces/surface_manager.h"
  23 #include "cc/trees/blocking_task_runner.h"
  24
  25 namespace cc {
  26 namespace {
  27
  28 void MoveMatchingRequests(
  29     RenderPassId id,
  30     std::multimap<RenderPassId, CopyOutputRequest*>* copy_requests,
  31     ScopedPtrVector<CopyOutputRequest>* output_requests) {
  32   auto request_range = copy_requests->equal_range(id);
  33   for (auto it = request_range.first; it != request_range.second; ++it) {
  34     DCHECK(it->second);
  35     output_requests->push_back(scoped_ptr<CopyOutputRequest>(it->second));
  36     it->second = nullptr;
  37   }
  38   copy_requests->erase(request_range.first, request_range.second);
  39 }
  40
  41 }  // namespace
  42
  43 SurfaceAggregator::SurfaceAggregator(SurfaceManager* manager,
  44                                      ResourceProvider* provider)
  45     : manager_(manager), provider_(provider), next_render_pass_id_(1) {
  46   DCHECK(manager_);
  47 }
  48
  49 SurfaceAggregator::~SurfaceAggregator() {}
  50
  51 // Create a clip rect for an aggregated quad from the original clip rect and
  52 // the clip rect from the surface it's on.
  53 SurfaceAggregator::ClipData SurfaceAggregator::CalculateClipRect(
  54     const ClipData& surface_clip,
  55     const ClipData& quad_clip,
  56     const gfx::Transform& content_to_target_transform) {
  57   ClipData out_clip;
  58   if (surface_clip.is_clipped)
  59     out_clip = surface_clip;
  60
  61   if (quad_clip.is_clipped) {
  62     // TODO(jamesr): This only works if content_to_target_transform maps integer
  63     // rects to integer rects.
  64     gfx::Rect final_clip = MathUtil::MapEnclosingClippedRect(
  65         content_to_target_transform, quad_clip.rect);
  66     if (out_clip.is_clipped)
  67       out_clip.rect.Intersect(final_clip);
  68     else
  69       out_clip.rect = final_clip;
  70     out_clip.is_clipped = true;
  71   }
  72
  73   return out_clip;
  74 }
  75
  76 class SurfaceAggregator::RenderPassIdAllocator {
  77  public:
  78   explicit RenderPassIdAllocator(int* next_index) : next_index_(next_index) {}
  79   ~RenderPassIdAllocator() {}
  80
  81   void AddKnownPass(RenderPassId id) {
  82     if (id_to_index_map_.find(id) != id_to_index_map_.end())
  83       return;
  84     id_to_index_map_[id] = (*next_index_)++;
  85   }
  86
  87   RenderPassId Remap(RenderPassId id) {
  88     DCHECK(id_to_index_map_.find(id) != id_to_index_map_.end());
  89     return RenderPassId(1, id_to_index_map_[id]);
  90   }
  91
  92  private:
  93   base::hash_map<RenderPassId, int> id_to_index_map_;
  94   int* next_index_;
  95
  96   DISALLOW_COPY_AND_ASSIGN(RenderPassIdAllocator);
  97 };
  98
  99 static void UnrefHelper(base::WeakPtr<SurfaceFactory> surface_factory,
 100                         const ReturnedResourceArray& resources,
 101                         BlockingTaskRunner* main_thread_task_runner) {
 102   if (surface_factory)
 103     surface_factory->UnrefResources(resources);
 104 }
 105
 106 RenderPassId SurfaceAggregator::RemapPassId(RenderPassId surface_local_pass_id,
 107                                             SurfaceId surface_id) {
 108   RenderPassIdAllocator* allocator = render_pass_allocator_map_.get(surface_id);
 109   if (!allocator) {
 110     allocator = new RenderPassIdAllocator(&next_render_pass_id_);
 111     render_pass_allocator_map_.set(surface_id, make_scoped_ptr(allocator));
 112   }
 113   allocator->AddKnownPass(surface_local_pass_id);
 114   return allocator->Remap(surface_local_pass_id);
 115 }
 116
 117 int SurfaceAggregator::ChildIdForSurface(Surface* surface) {
 118   SurfaceToResourceChildIdMap::iterator it =
 119       surface_id_to_resource_child_id_.find(surface->surface_id());
 120   if (it == surface_id_to_resource_child_id_.end()) {
 121     int child_id =
 122         provider_->CreateChild(base::Bind(&UnrefHelper, surface->factory()));
 123     if (surface->factory()) {
 124       provider_->SetChildNeedsSyncPoints(
 125           child_id, surface->factory()->needs_sync_points());
 126     }
 127     surface_id_to_resource_child_id_[surface->surface_id()] = child_id;
 128     return child_id;
 129   } else {
 130     return it->second;
 131   }
 132 }
 133
 134 static ResourceProvider::ResourceId ResourceRemapHelper(
 135     const ResourceProvider::ResourceIdMap& child_to_parent_map,
 136     ResourceProvider::ResourceId id) {
 137   ResourceProvider::ResourceIdMap::const_iterator it =
 138       child_to_parent_map.find(id);
 139   DCHECK(it != child_to_parent_map.end());
 140
 141   DCHECK_EQ(it->first, id);
 142   ResourceProvider::ResourceId remapped_id = it->second;
 143   return remapped_id;
 144 }
 145
 146 static ResourceProvider::ResourceId ValidateResourceHelper(
 147     bool* invalid_frame,
 148     const ResourceProvider::ResourceIdMap& child_to_parent_map,
 149     ResourceProvider::ResourceIdSet* resources_in_frame,
 150     ResourceProvider::ResourceId id) {
 151   ResourceProvider::ResourceIdMap::const_iterator it =
 152       child_to_parent_map.find(id);
 153   if (it == child_to_parent_map.end()) {
 154     *invalid_frame = true;
 155     return id;
 156   }
 157   resources_in_frame->insert(id);
 158   return id;
 159 }
 160
 161 bool SurfaceAggregator::ValidateResources(
 162     Surface* surface,
 163     const DelegatedFrameData* frame_data) {
 164   if (!provider_)  // TODO(jamesr): hack for unit tests that don't set up rp
 165     return false;
 166
 167   int child_id = ChildIdForSurface(surface);
 168   if (surface->factory())
 169     surface->factory()->RefResources(frame_data->resource_list);
 170   provider_->ReceiveFromChild(child_id, frame_data->resource_list);
 171
 172   ResourceProvider::ResourceIdSet referenced_resources;
 173   size_t reserve_size = frame_data->resource_list.size();
 174 #if defined(COMPILER_MSVC)
 175   referenced_resources.reserve(reserve_size);
 176 #elif defined(COMPILER_GCC)
 177   // Pre-standard hash-tables only implement resize, which behaves similarly
 178   // to reserve for these keys. Resizing to 0 may also be broken (particularly
 179   // on stlport).
 180   // TODO(jbauman): Replace with reserve when C++11 is supported everywhere.
 181   if (reserve_size)
 182     referenced_resources.resize(reserve_size);
 183 #endif
 184
 185   bool invalid_frame = false;
 186   DrawQuad::ResourceIteratorCallback remap =
 187       base::Bind(&ValidateResourceHelper, &invalid_frame,
 188                  base::ConstRef(provider_->GetChildToParentMap(child_id)),
 189                  &referenced_resources);
 190   for (const auto& render_pass : frame_data->render_pass_list) {
 191     for (const auto& quad : render_pass->quad_list)
 192       quad->IterateResources(remap);
 193   }
 194
 195   if (!invalid_frame)
 196     provider_->DeclareUsedResourcesFromChild(child_id, referenced_resources);
 197
 198   return invalid_frame;
 199 }
 200
 201 gfx::Rect SurfaceAggregator::DamageRectForSurface(const Surface* surface,
 202                                                   const RenderPass& source,
 203                                                   const gfx::Rect& full_rect) {
 204   int previous_index = previous_contained_surfaces_[surface->surface_id()];
 205   if (previous_index == surface->frame_index())
 206     return gfx::Rect();
 207   else if (previous_index == surface->frame_index() - 1)
 208     return source.damage_rect;
 209   return full_rect;
 210 }
 211
 212 void SurfaceAggregator::HandleSurfaceQuad(
 213     const SurfaceDrawQuad* surface_quad,
 214     const gfx::Transform& content_to_target_transform,
 215     const ClipData& clip_rect,
 216     RenderPass* dest_pass) {
 217   SurfaceId surface_id = surface_quad->surface_id;
 218   // If this surface's id is already in our referenced set then it creates
 219   // a cycle in the graph and should be dropped.
 220   if (referenced_surfaces_.count(surface_id))
 221     return;
 222   Surface* surface = manager_->GetSurfaceForId(surface_id);
 223   if (!surface) {
 224     contained_surfaces_[surface_id] = 0;
 225     return;
 226   }
 227   contained_surfaces_[surface_id] = surface->frame_index();
 228   const CompositorFrame* frame = surface->GetEligibleFrame();
 229   if (!frame)
 230     return;
 231   const DelegatedFrameData* frame_data = frame->delegated_frame_data.get();
 232   if (!frame_data)
 233     return;
 234
 235   std::multimap<RenderPassId, CopyOutputRequest*> copy_requests;
 236   surface->TakeCopyOutputRequests(&copy_requests);
 237
 238   const RenderPassList& render_pass_list = frame_data->render_pass_list;
 239   bool invalid_frame = ValidateResources(surface, frame_data);
 240   if (invalid_frame) {
 241     for (auto& request : copy_requests) {
 242       request.second->SendEmptyResult();
 243       delete request.second;
 244     }
 245     return;
 246   }
 247
 248   SurfaceSet::iterator it = referenced_surfaces_.insert(surface_id).first;
 249   DrawQuad::ResourceIteratorCallback remap;
 250   if (provider_) {
 251     int child_id = ChildIdForSurface(surface);
 252     remap =
 253         base::Bind(&ResourceRemapHelper,
 254                    base::ConstRef(provider_->GetChildToParentMap(child_id)));
 255   }
 256
 257   bool merge_pass = surface_quad->opacity() == 1.f && copy_requests.empty();
 258
 259   gfx::Rect surface_damage = DamageRectForSurface(
 260       surface, *render_pass_list.back(), surface_quad->visible_rect);
 261   const RenderPassList& referenced_passes = render_pass_list;
 262   size_t passes_to_copy =
 263       merge_pass ? referenced_passes.size() - 1 : referenced_passes.size();
 264   for (size_t j = 0; j < passes_to_copy; ++j) {
 265     const RenderPass& source = *referenced_passes[j];
 266
 267     size_t sqs_size = source.shared_quad_state_list.size();
 268     size_t dq_size = source.quad_list.size();
 269     scoped_ptr<RenderPass> copy_pass(RenderPass::Create(sqs_size, dq_size));
 270
 271     RenderPassId remapped_pass_id = RemapPassId(source.id, surface_id);
 272
 273     copy_pass->SetAll(remapped_pass_id, source.output_rect, gfx::Rect(),
 274                       source.transform_to_root_target,
 275                       source.has_transparent_background);
 276
 277     MoveMatchingRequests(source.id, &copy_requests, &copy_pass->copy_requests);
 278
 279     // Contributing passes aggregated in to the pass list need to take the
 280     // transform of the surface quad into account to update their transform to
 281     // the root surface.
 282     copy_pass->transform_to_root_target.ConcatTransform(
 283         surface_quad->quadTransform());
 284     copy_pass->transform_to_root_target.ConcatTransform(
 285         content_to_target_transform);
 286     copy_pass->transform_to_root_target.ConcatTransform(
 287         dest_pass->transform_to_root_target);
 288
 289     CopyQuadsToPass(source.quad_list, source.shared_quad_state_list, remap,
 290                     gfx::Transform(), ClipData(), copy_pass.get(), surface_id);
 291
 292     if (j == referenced_passes.size() - 1)
 293       surface_damage = gfx::UnionRects(surface_damage, copy_pass->damage_rect);
 294
 295     dest_pass_list_->push_back(copy_pass.Pass());
 296   }
 297
 298   const RenderPass& last_pass = *render_pass_list.back();
 299   if (merge_pass) {
 300     // TODO(jamesr): Clean up last pass special casing.
 301     const QuadList& quads = last_pass.quad_list;
 302
 303     gfx::Transform surface_transform = surface_quad->quadTransform();
 304     surface_transform.ConcatTransform(content_to_target_transform);
 305
 306     // Intersect the transformed visible rect and the clip rect to create a
 307     // smaller cliprect for the quad.
 308     ClipData surface_quad_clip_rect(
 309         true, MathUtil::MapEnclosingClippedRect(surface_quad->quadTransform(),
 310                                                 surface_quad->visible_rect));
 311     if (surface_quad->isClipped())
 312       surface_quad_clip_rect.rect.Intersect(surface_quad->clipRect());
 313
 314     ClipData quads_clip = CalculateClipRect(clip_rect, surface_quad_clip_rect,
 315                                             content_to_target_transform);
 316
 317     CopyQuadsToPass(quads, last_pass.shared_quad_state_list, remap,
 318                     surface_transform, quads_clip, dest_pass, surface_id);
 319   } else {
 320     RenderPassId remapped_pass_id = RemapPassId(last_pass.id, surface_id);
 321
 322     CopySharedQuadState(surface_quad->shared_quad_state,
 323                         content_to_target_transform, clip_rect, dest_pass);
 324
 325     SharedQuadState* shared_quad_state =
 326         dest_pass->shared_quad_state_list.back();
 327     RenderPassDrawQuad* quad =
 328         dest_pass->CreateAndAppendDrawQuad<RenderPassDrawQuad>();
 329     quad->SetNew(shared_quad_state,
 330                  surface_quad->rect,
 331                  surface_quad->visible_rect,
 332                  remapped_pass_id,
 333                  0,
 334                  gfx::Vector2dF(),
 335                  gfx::Size(),
 336                  FilterOperations(),
 337                  gfx::Vector2dF(),
 338                  FilterOperations());
 339   }
 340   dest_pass->damage_rect =
 341       gfx::UnionRects(dest_pass->damage_rect,
 342                       MathUtil::MapEnclosingClippedRect(
 343                           surface_quad->quadTransform(), surface_damage));
 344
 345   referenced_surfaces_.erase(it);
 346 }
 347
 348 void SurfaceAggregator::CopySharedQuadState(
 349     const SharedQuadState* source_sqs,
 350     const gfx::Transform& content_to_target_transform,
 351     const ClipData& clip_rect,
 352     RenderPass* dest_render_pass) {
 353   SharedQuadState* copy_shared_quad_state =
 354       dest_render_pass->CreateAndAppendSharedQuadState();
 355   copy_shared_quad_state->CopyFrom(source_sqs);
 356   // content_to_target_transform contains any transformation that may exist
 357   // between the context that these quads are being copied from (i.e. the
 358   // surface's draw transform when aggregated from within a surface) to the
 359   // target space of the pass. This will be identity except when copying the
 360   // root draw pass from a surface into a pass when the surface draw quad's
 361   // transform is not identity.
 362   copy_shared_quad_state->content_to_target_transform.ConcatTransform(
 363       content_to_target_transform);
 364
 365   ClipData new_clip_rect = CalculateClipRect(
 366       clip_rect, ClipData(source_sqs->is_clipped, source_sqs->clip_rect),
 367       content_to_target_transform);
 368   copy_shared_quad_state->is_clipped = new_clip_rect.is_clipped;
 369   copy_shared_quad_state->clip_rect = new_clip_rect.rect;
 370 }
 371
 372 void SurfaceAggregator::CopyQuadsToPass(
 373     const QuadList& source_quad_list,
 374     const SharedQuadStateList& source_shared_quad_state_list,
 375     const DrawQuad::ResourceIteratorCallback& remap,
 376     const gfx::Transform& content_to_target_transform,
 377     const ClipData& clip_rect,
 378     RenderPass* dest_pass,
 379     SurfaceId surface_id) {
 380   const SharedQuadState* last_copied_source_shared_quad_state = NULL;
 381
 382   SharedQuadStateList::ConstIterator sqs_iter =
 383       source_shared_quad_state_list.begin();
 384   for (const auto& quad : source_quad_list) {
 385     while (quad->shared_quad_state != *sqs_iter) {
 386       ++sqs_iter;
 387       DCHECK(sqs_iter != source_shared_quad_state_list.end());
 388     }
 389     DCHECK_EQ(quad->shared_quad_state, *sqs_iter);
 390
 391     if (quad->material == DrawQuad::SURFACE_CONTENT) {
 392       const SurfaceDrawQuad* surface_quad = SurfaceDrawQuad::MaterialCast(quad);
 393       HandleSurfaceQuad(surface_quad, content_to_target_transform, clip_rect,
 394                         dest_pass);
 395     } else {
 396       if (quad->shared_quad_state != last_copied_source_shared_quad_state) {
 397         CopySharedQuadState(quad->shared_quad_state,
 398                             content_to_target_transform, clip_rect, dest_pass);
 399         last_copied_source_shared_quad_state = quad->shared_quad_state;
 400       }
 401       DrawQuad* dest_quad;
 402       if (quad->material == DrawQuad::RENDER_PASS) {
 403         const RenderPassDrawQuad* pass_quad =
 404             RenderPassDrawQuad::MaterialCast(quad);
 405         RenderPassId original_pass_id = pass_quad->render_pass_id;
 406         RenderPassId remapped_pass_id =
 407             RemapPassId(original_pass_id, surface_id);
 408
 409         gfx::Rect pass_damage;
 410         for (const auto* pass : *dest_pass_list_) {
 411           if (pass->id == remapped_pass_id) {
 412             pass_damage = pass->damage_rect;
 413             break;
 414           }
 415         }
 416
 417         dest_quad = dest_pass->CopyFromAndAppendRenderPassDrawQuad(
 418             pass_quad, dest_pass->shared_quad_state_list.back(),
 419             remapped_pass_id);
 420         dest_pass->damage_rect =
 421             gfx::UnionRects(dest_pass->damage_rect,
 422                             MathUtil::MapEnclosingClippedRect(
 423                                 dest_quad->quadTransform(), pass_damage));
 424       } else {
 425         dest_quad = dest_pass->CopyFromAndAppendDrawQuad(
 426             quad, dest_pass->shared_quad_state_list.back());
 427       }
 428       if (!remap.is_null())
 429         dest_quad->IterateResources(remap);
 430     }
 431   }
 432 }
 433
 434 void SurfaceAggregator::CopyPasses(const DelegatedFrameData* frame_data,
 435                                    Surface* surface) {
 436   // The root surface is allowed to have copy output requests, so grab them
 437   // off its render passes.
 438   std::multimap<RenderPassId, CopyOutputRequest*> copy_requests;
 439   surface->TakeCopyOutputRequests(&copy_requests);
 440
 441   const RenderPassList& source_pass_list = frame_data->render_pass_list;
 442   bool invalid_frame = ValidateResources(surface, frame_data);
 443   DCHECK(!invalid_frame);
 444   if (invalid_frame)
 445     return;
 446
 447   DrawQuad::ResourceIteratorCallback remap;
 448   if (provider_) {
 449     int child_id = ChildIdForSurface(surface);
 450     remap =
 451         base::Bind(&ResourceRemapHelper,
 452                    base::ConstRef(provider_->GetChildToParentMap(child_id)));
 453   }
 454
 455   for (size_t i = 0; i < source_pass_list.size(); ++i) {
 456     const RenderPass& source = *source_pass_list[i];
 457
 458     size_t sqs_size = source.shared_quad_state_list.size();
 459     size_t dq_size = source.quad_list.size();
 460     scoped_ptr<RenderPass> copy_pass(RenderPass::Create(sqs_size, dq_size));
 461
 462     MoveMatchingRequests(source.id, &copy_requests, &copy_pass->copy_requests);
 463
 464     RenderPassId remapped_pass_id =
 465         RemapPassId(source.id, surface->surface_id());
 466
 467     gfx::Rect damage_rect =
 468         (i < source_pass_list.size() - 1)
 469             ? gfx::Rect()
 470             : DamageRectForSurface(surface, source, source.output_rect);
 471     copy_pass->SetAll(remapped_pass_id, source.output_rect, damage_rect,
 472                       source.transform_to_root_target,
 473                       source.has_transparent_background);
 474
 475     CopyQuadsToPass(source.quad_list, source.shared_quad_state_list, remap,
 476                     gfx::Transform(), ClipData(), copy_pass.get(),
 477                     surface->surface_id());
 478
 479     dest_pass_list_->push_back(copy_pass.Pass());
 480   }
 481 }
 482
 483 void SurfaceAggregator::RemoveUnreferencedChildren() {
 484   for (const auto& surface : previous_contained_surfaces_) {
 485     if (!contained_surfaces_.count(surface.first)) {
 486       SurfaceToResourceChildIdMap::iterator it =
 487           surface_id_to_resource_child_id_.find(surface.first);
 488       if (it != surface_id_to_resource_child_id_.end()) {
 489         provider_->DestroyChild(it->second);
 490         surface_id_to_resource_child_id_.erase(it);
 491       }
 492
 493       Surface* surface_ptr = manager_->GetSurfaceForId(surface.first);
 494       if (surface_ptr)
 495         surface_ptr->RunDrawCallbacks(SurfaceDrawStatus::DRAW_SKIPPED);
 496     }
 497   }
 498 }
 499
 500 scoped_ptr<CompositorFrame> SurfaceAggregator::Aggregate(SurfaceId surface_id) {
 501   Surface* surface = manager_->GetSurfaceForId(surface_id);
 502   DCHECK(surface);
 503   contained_surfaces_[surface_id] = surface->frame_index();
 504   const CompositorFrame* root_surface_frame = surface->GetEligibleFrame();
 505   if (!root_surface_frame)
 506     return nullptr;
 507   TRACE_EVENT0("cc", "SurfaceAggregator::Aggregate");
 508
 509   scoped_ptr<CompositorFrame> frame(new CompositorFrame);
 510   frame->delegated_frame_data = make_scoped_ptr(new DelegatedFrameData);
 511
 512   DCHECK(root_surface_frame->delegated_frame_data);
 513
 514   SurfaceSet::iterator it = referenced_surfaces_.insert(surface_id).first;
 515
 516   dest_resource_list_ = &frame->delegated_frame_data->resource_list;
 517   dest_pass_list_ = &frame->delegated_frame_data->render_pass_list;
 518
 519   CopyPasses(root_surface_frame->delegated_frame_data.get(), surface);
 520
 521   referenced_surfaces_.erase(it);
 522   DCHECK(referenced_surfaces_.empty());
 523
 524   if (dest_pass_list_->empty())
 525     return nullptr;
 526
 527   dest_pass_list_ = NULL;
 528   RemoveUnreferencedChildren();
 529   contained_surfaces_.swap(previous_contained_surfaces_);
 530   contained_surfaces_.clear();
 531
 532   for (SurfaceIndexMap::iterator it = previous_contained_surfaces_.begin();
 533        it != previous_contained_surfaces_.end();
 534        ++it) {
 535     Surface* surface = manager_->GetSurfaceForId(it->first);
 536     if (surface)
 537       surface->TakeLatencyInfo(&frame->metadata.latency_info);
 538   }
 539
 540   // TODO(jamesr): Aggregate all resource references into the returned frame's
 541   // resource list.
 542
 543   return frame.Pass();
 544 }
 545
 546 void SurfaceAggregator::ReleaseResources(SurfaceId surface_id) {
 547   SurfaceToResourceChildIdMap::iterator it =
 548       surface_id_to_resource_child_id_.find(surface_id);
 549   if (it != surface_id_to_resource_child_id_.end()) {
 550     provider_->DestroyChild(it->second);
 551     surface_id_to_resource_child_id_.erase(it);
 552   }
 553 }
 554
 555 void SurfaceAggregator::SetFullDamageForSurface(SurfaceId surface_id) {
 556   auto it = previous_contained_surfaces_.find(surface_id);
 557   if (it == previous_contained_surfaces_.end())
 558     return;
 559   // Set the last drawn index as 0 to ensure full damage next time it's drawn.
 560   it->second = 0;
 561 }
 562
 563 }  // namespace cc