Move html_viewer from mojo/services to components.

mojo/services/html_viewer/discardable_memory_allocator.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 "mojo/services/html_viewer/discardable_memory_allocator.h"
-
-#include "base/memory/discardable_memory.h"
-#include "base/memory/weak_ptr.h"
-#include "base/stl_util.h"
-
-namespace html_viewer {
-
-// Represents an actual memory chunk. This is an object owned by
-// DiscardableMemoryAllocator. DiscardableMemoryChunkImpl are passed to the
-// rest of the program, and access this memory through a weak ptr.
-class DiscardableMemoryAllocator::OwnedMemoryChunk {
- public:
-  OwnedMemoryChunk(size_t size, DiscardableMemoryAllocator* allocator)
-      : is_locked_(true),
-        size_(size),
-        data_(new uint8_t[size]),
-        allocator_(allocator),
-        weak_factory_(this) {}
-  ~OwnedMemoryChunk() {}
-
-  void Lock() {
-    DCHECK(!is_locked_);
-    is_locked_ = true;
-    allocator_->NotifyLocked(unlocked_position_);
-  }
-
-  void Unlock() {
-    DCHECK(is_locked_);
-    is_locked_ = false;
-    unlocked_position_ = allocator_->NotifyUnlocked(this);
-  }
-
-  bool is_locked() const { return is_locked_; }
-  size_t size() const { return size_; }
-  void* data() const {
-    DCHECK(is_locked_);
-    return data_.get();
-  }
-
-  base::WeakPtr<OwnedMemoryChunk> GetWeakPtr() {
-    return weak_factory_.GetWeakPtr();
-  }
-
- private:
-  bool is_locked_;
-  size_t size_;
-  scoped_ptr<uint8_t[]> data_;
-  DiscardableMemoryAllocator* allocator_;
-
-  std::list<OwnedMemoryChunk*>::iterator unlocked_position_;
-
-  base::WeakPtrFactory<OwnedMemoryChunk> weak_factory_;
-
-  DISALLOW_IMPLICIT_CONSTRUCTORS(OwnedMemoryChunk);
-};
-
-namespace {
-
-// Interface to the rest of the program. These objects are owned outside of the
-// allocator and wrap a weak ptr.
-class DiscardableMemoryChunkImpl : public base::DiscardableMemory {
- public:
-  explicit DiscardableMemoryChunkImpl(
-      base::WeakPtr<DiscardableMemoryAllocator::OwnedMemoryChunk> chunk)
-      : memory_chunk_(chunk) {}
-  ~DiscardableMemoryChunkImpl() override {
-    // Either the memory chunk is invalid (because the backing has gone away),
-    // or the memory chunk is unlocked (because leaving the chunk locked once
-    // we deallocate means the chunk will never get cleaned up).
-    DCHECK(!memory_chunk_ || !memory_chunk_->is_locked());
-  }
-
-  // Overridden from DiscardableMemoryChunk:
-  bool Lock() override {
-    if (!memory_chunk_)
-      return false;
-
-    memory_chunk_->Lock();
-    return true;
-  }
-
-  void Unlock() override {
-    DCHECK(memory_chunk_);
-    memory_chunk_->Unlock();
-  }
-
-  void* data() const override {
-    if (memory_chunk_)
-      return memory_chunk_->data();
-    return nullptr;
-  }
-
- private:
-  base::WeakPtr<DiscardableMemoryAllocator::OwnedMemoryChunk> memory_chunk_;
-
-  DISALLOW_IMPLICIT_CONSTRUCTORS(DiscardableMemoryChunkImpl);
-};
-
-}  // namespace
-
-DiscardableMemoryAllocator::DiscardableMemoryAllocator(
-    size_t desired_max_memory)
-    : desired_max_memory_(desired_max_memory),
-      total_live_memory_(0u),
-      locked_chunks_(0) {
-}
-
-DiscardableMemoryAllocator::~DiscardableMemoryAllocator() {
-  DCHECK_EQ(0, locked_chunks_);
-  STLDeleteElements(&live_unlocked_chunks_);
-}
-
-scoped_ptr<base::DiscardableMemory>
-DiscardableMemoryAllocator::AllocateLockedDiscardableMemory(size_t size) {
-  OwnedMemoryChunk* chunk = new OwnedMemoryChunk(size, this);
-  total_live_memory_ += size;
-  locked_chunks_++;
-
-  // Go through the list of unlocked live chunks starting from the least
-  // recently used, freeing as many as we can until we get our size under the
-  // desired maximum.
-  auto it = live_unlocked_chunks_.begin();
-  while (total_live_memory_ > desired_max_memory_ &&
-         it != live_unlocked_chunks_.end()) {
-    total_live_memory_ -= (*it)->size();
-    delete *it;
-    it = live_unlocked_chunks_.erase(it);
-  }
-
-  return make_scoped_ptr(new DiscardableMemoryChunkImpl(chunk->GetWeakPtr()));
-}
-
-std::list<DiscardableMemoryAllocator::OwnedMemoryChunk*>::iterator
-DiscardableMemoryAllocator::NotifyUnlocked(
-    DiscardableMemoryAllocator::OwnedMemoryChunk* chunk) {
-  locked_chunks_--;
-  return live_unlocked_chunks_.insert(live_unlocked_chunks_.end(), chunk);
-}
-
-void DiscardableMemoryAllocator::NotifyLocked(
-    std::list<OwnedMemoryChunk*>::iterator it) {
-  locked_chunks_++;
-  live_unlocked_chunks_.erase(it);
-}
-
-}  // namespace html_viewer