// Copyright 2014 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 "cc/surfaces/surface_manager.h"

#include <stddef.h>
#include <stdint.h>

#include "base/logging.h"
#include "cc/surfaces/surface.h"
#include "cc/surfaces/surface_id_allocator.h"

namespace cc {

SurfaceManager::SurfaceManager() {
  thread_checker_.DetachFromThread();
}

SurfaceManager::~SurfaceManager() {
  DCHECK(thread_checker_.CalledOnValidThread());
  for (SurfaceDestroyList::iterator it = surfaces_to_destroy_.begin();
       it != surfaces_to_destroy_.end();
       ++it) {
    DeregisterSurface((*it)->surface_id());
    delete *it;
  }
}

void SurfaceManager::RegisterSurface(Surface* surface) {
  DCHECK(thread_checker_.CalledOnValidThread());
  DCHECK(surface);
  DCHECK(!surface_map_.count(surface->surface_id()));
  surface_map_[surface->surface_id()] = surface;
}

void SurfaceManager::DeregisterSurface(SurfaceId surface_id) {
  DCHECK(thread_checker_.CalledOnValidThread());
  SurfaceMap::iterator it = surface_map_.find(surface_id);
  DCHECK(it != surface_map_.end());
  surface_map_.erase(it);
}

void SurfaceManager::Destroy(scoped_ptr<Surface> surface) {
  DCHECK(thread_checker_.CalledOnValidThread());
  surface->set_destroyed(true);
  surfaces_to_destroy_.push_back(surface.release());
  GarbageCollectSurfaces();
}

void SurfaceManager::DidSatisfySequences(uint32_t id_namespace,
                                         std::vector<uint32_t>* sequence) {
  DCHECK(thread_checker_.CalledOnValidThread());
  for (std::vector<uint32_t>::iterator it = sequence->begin();
       it != sequence->end();
       ++it) {
    satisfied_sequences_.insert(SurfaceSequence(id_namespace, *it));
  }
  sequence->clear();
  GarbageCollectSurfaces();
}

void SurfaceManager::RegisterSurfaceIdNamespace(uint32_t id_namespace) {
  bool inserted = valid_surface_id_namespaces_.insert(id_namespace).second;
  DCHECK(inserted);
}

void SurfaceManager::InvalidateSurfaceIdNamespace(uint32_t id_namespace) {
  valid_surface_id_namespaces_.erase(id_namespace);
  GarbageCollectSurfaces();
}

void SurfaceManager::GarbageCollectSurfaces() {
  // Simple mark and sweep GC.
  // TODO(jbauman): Reduce the amount of work when nothing needs to be
  // destroyed.
  std::vector<SurfaceId> live_surfaces;
  std::set<SurfaceId> live_surfaces_set;

  // GC roots are surfaces that have not been destroyed, or have not had all
  // their destruction dependencies satisfied.
  for (auto& map_entry : surface_map_) {
    map_entry.second->SatisfyDestructionDependencies(
        &satisfied_sequences_, &valid_surface_id_namespaces_);
    if (!map_entry.second->destroyed() ||
        map_entry.second->GetDestructionDependencyCount()) {
      live_surfaces_set.insert(map_entry.first);
      live_surfaces.push_back(map_entry.first);
    }
  }

  // Mark all surfaces reachable from live surfaces by adding them to
  // live_surfaces and live_surfaces_set.
  for (size_t i = 0; i < live_surfaces.size(); i++) {
    Surface* surf = surface_map_[live_surfaces[i]];
    DCHECK(surf);

    for (SurfaceId id : surf->referenced_surfaces()) {
      if (live_surfaces_set.count(id))
        continue;

      Surface* surf2 = GetSurfaceForId(id);
      if (surf2) {
        live_surfaces.push_back(id);
        live_surfaces_set.insert(id);
      }
    }
  }

  // Destroy all remaining unreachable surfaces.
  for (SurfaceDestroyList::iterator dest_it = surfaces_to_destroy_.begin();
       dest_it != surfaces_to_destroy_.end();) {
    if (!live_surfaces_set.count((*dest_it)->surface_id())) {
      scoped_ptr<Surface> surf(*dest_it);
      DeregisterSurface(surf->surface_id());
      dest_it = surfaces_to_destroy_.erase(dest_it);
    } else {
      ++dest_it;
    }
  }
}

Surface* SurfaceManager::GetSurfaceForId(SurfaceId surface_id) {
  DCHECK(thread_checker_.CalledOnValidThread());
  SurfaceMap::iterator it = surface_map_.find(surface_id);
  if (it == surface_map_.end())
    return NULL;
  return it->second;
}

bool SurfaceManager::SurfaceModified(SurfaceId surface_id) {
  DCHECK(thread_checker_.CalledOnValidThread());
  bool changed = false;
  FOR_EACH_OBSERVER(SurfaceDamageObserver, observer_list_,
                    OnSurfaceDamaged(surface_id, &changed));
  return changed;
}

}  // namespace cc