Remove the flash specific disk cache backend.

net/disk_cache/flash/log_store.cc

-// Copyright (c) 2012 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 "base/logging.h"
-#include "base/memory/scoped_ptr.h"
-#include "base/stl_util.h"
-#include "net/disk_cache/flash/format.h"
-#include "net/disk_cache/flash/log_store.h"
-#include "net/disk_cache/flash/segment.h"
-#include "net/disk_cache/flash/storage.h"
-
-namespace disk_cache {
-
-LogStore::LogStore(const base::FilePath& path, int32 size)
-    : storage_(path, size),
-      num_segments_(size / kFlashSegmentSize),
-      open_segments_(num_segments_),
-      write_index_(0),
-      current_entry_id_(-1),
-      current_entry_num_bytes_left_to_write_(0),
-      init_(false),
-      closed_(false) {
-  DCHECK(size % kFlashSegmentSize == 0);
-}
-
-LogStore::~LogStore() {
-  DCHECK(!init_ || closed_);
-  STLDeleteElements(&open_segments_);
-}
-
-bool LogStore::Init() {
-  DCHECK(!init_);
-  if (!storage_.Init())
-    return false;
-
-  // TODO(agayev): Once we start persisting segment metadata to disk, we will
-  // start from where we left off during the last shutdown.
-  scoped_ptr<Segment> segment(new Segment(write_index_, false, &storage_));
-  if (!segment->Init())
-    return false;
-
-  segment->AddUser();
-  open_segments_[write_index_] = segment.release();
-  init_ = true;
-  return true;
-}
-
-bool LogStore::Close() {
-  DCHECK(init_ && !closed_);
-  open_segments_[write_index_]->ReleaseUser();
-  if (!open_segments_[write_index_]->Close())
-    return false;
-  closed_ = true;
-  return true;
-  // TODO(agayev): persist metadata to disk.
-}
-
-bool LogStore::CreateEntry(int32 size, int32* id) {
-  DCHECK(init_ && !closed_);
-  DCHECK(current_entry_id_ == -1 && size <= disk_cache::kFlashSegmentFreeSpace);
-
-  // TODO(agayev): Avoid large entries from leaving the segments almost empty.
-  if (!open_segments_[write_index_]->CanHold(size)) {
-    if (!open_segments_[write_index_]->Close())
-      return false;
-
-    open_segments_[write_index_]->ReleaseUser();
-    if (open_segments_[write_index_]->HasNoUsers()) {
-      delete open_segments_[write_index_];
-      open_segments_[write_index_] = NULL;
-    }
-
-    write_index_ = GetNextSegmentIndex();
-    scoped_ptr<Segment> segment(new Segment(write_index_, false, &storage_));
-    if (!segment->Init())
-      return false;
-
-    segment->AddUser();
-    open_segments_[write_index_] = segment.release();
-  }
-
-  *id = open_segments_[write_index_]->write_offset();
-  open_segments_[write_index_]->StoreOffset(*id);
-  current_entry_id_ = *id;
-  current_entry_num_bytes_left_to_write_ = size;
-  open_entries_.insert(current_entry_id_);
-  return true;
-}
-
-void LogStore::DeleteEntry(int32 id, int32 size) {
-  DCHECK(init_ && !closed_);
-  DCHECK(open_entries_.find(id) == open_entries_.end());
-  // TODO(agayev): Increment the number of dead bytes in the segment metadata
-  // for the segment identified by |index|.
-}
-
-bool LogStore::WriteData(const void* buffer, int32 size) {
-  DCHECK(init_ && !closed_);
-  DCHECK(current_entry_id_ != -1 &&
-         size <= current_entry_num_bytes_left_to_write_);
-  if (open_segments_[write_index_]->WriteData(buffer, size)) {
-    current_entry_num_bytes_left_to_write_ -= size;
-    return true;
-  }
-  return false;
-}
-
-bool LogStore::OpenEntry(int32 id) {
-  DCHECK(init_ && !closed_);
-  if (open_entries_.find(id) != open_entries_.end())
-    return false;
-
-  // Segment is already open.
-  int32 index = id / disk_cache::kFlashSegmentSize;
-  if (open_segments_[index]) {
-    if (!open_segments_[index]->HaveOffset(id))
-      return false;
-    open_segments_[index]->AddUser();
-    open_entries_.insert(id);
-    return true;
-  }
-
-  // Segment is not open.
-  scoped_ptr<Segment> segment(new Segment(index, true, &storage_));
-  if (!segment->Init() || !segment->HaveOffset(id))
-    return false;
-
-  segment->AddUser();
-  open_segments_[index] = segment.release();
-  open_entries_.insert(id);
-  return true;
-}
-
-bool LogStore::ReadData(int32 id, void* buffer, int32 size,
-                                  int32 offset) const {
-  DCHECK(init_ && !closed_);
-  DCHECK(open_entries_.find(id) != open_entries_.end());
-
-  int32 index = id / disk_cache::kFlashSegmentSize;
-  DCHECK(open_segments_[index] && open_segments_[index]->HaveOffset(id));
-  return open_segments_[index]->ReadData(buffer, size, id + offset);
-}
-
-void LogStore::CloseEntry(int32 id) {
-  DCHECK(init_ && !closed_);
-  std::set<int32>::iterator entry_iter = open_entries_.find(id);
-  DCHECK(entry_iter != open_entries_.end());
-
-  if (current_entry_id_ != -1) {
-    DCHECK(id == current_entry_id_ && !current_entry_num_bytes_left_to_write_);
-    open_entries_.erase(entry_iter);
-    current_entry_id_ = -1;
-    return;
-  }
-
-  int32 index = id / disk_cache::kFlashSegmentSize;
-  DCHECK(open_segments_[index]);
-  open_entries_.erase(entry_iter);
-
-  open_segments_[index]->ReleaseUser();
-  if (open_segments_[index]->HasNoUsers()) {
-    delete open_segments_[index];
-    open_segments_[index] = NULL;
-  }
-}
-
-int32 LogStore::GetNextSegmentIndex() {
-  DCHECK(init_ && !closed_);
-  int32 next_index = (write_index_ + 1) % num_segments_;
-
-  while (InUse(next_index)) {
-    next_index = (next_index + 1) % num_segments_;
-    DCHECK_NE(next_index, write_index_);
-  }
-  return next_index;
-}
-
-bool LogStore::InUse(int32 index) const {
-  DCHECK(init_ && !closed_);
-  DCHECK(index >= 0 && index < num_segments_);
-  return open_segments_[index] != NULL;
-}
-
-}  // namespace disk_cache