Added CacheEntry implementation.

net/disk_cache/flash/cache_entry.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 "net/base/io_buffer.h"
+#include "net/base/net_errors.h"
+#include "net/disk_cache/flash/cache_entry.h"
+#include "net/disk_cache/flash/format.h"
+#include "net/disk_cache/flash/log_structured_store.h"
+
+namespace disk_cache {
+
+CacheEntry::CacheEntry(LogStructuredStore* store)
+    : store_(store), id_(-1), init_(false), closed_(false) {
+  DCHECK(store);
+}
+
+CacheEntry::CacheEntry(LogStructuredStore* store, int32 id)
+    : store_(store), id_(id), init_(false), closed_(false) {
+  DCHECK(store);
+}
+
+CacheEntry::~CacheEntry() {
+  DCHECK(!init_ || closed_);
+}
+
+bool CacheEntry::Init() {
+  DCHECK(!init_);
+  if (!OnDisk()) {
+    init_ = true;
+    return true;
+  }
+
+  int32 stream_sizes[kFlashCacheEntryNumStreams];
+  COMPILE_ASSERT(sizeof(stream_sizes) == kFlashCacheEntryHeaderSize,
+                 invalid_cache_entry_header_size);
+
+  if (!store_->OpenEntry(id_) ||
+      !store_->ReadData(id_, stream_sizes, kFlashCacheEntryHeaderSize, 0)) {
+    return false;
+  }
+  for (int i = 0, offset = kFlashCacheEntryHeaderSize;
+       i < kFlashCacheEntryNumStreams; ++i) {
+    streams_[i].offset = offset;
+    streams_[i].size = stream_sizes[i];
+    offset += stream_sizes[i];
+  }
+  init_ = true;
+  return true;
+}
+
+bool CacheEntry::Close() {
+  DCHECK(init_ && !closed_);
+  if (OnDisk())
+    store_->CloseEntry(id_);
+  else if (!Save())
+    return false;
+  closed_ = true;
+  return true;
+}
+
+int32 CacheEntry::id() const {
+  DCHECK(init_);
+  return id_;
+}
+
+int32 CacheEntry::GetDataSize(int index) const {
+  DCHECK(init_);
+  return InvalidStream(index) ? 0 : streams_[index].size;
+}
+
+int CacheEntry::ReadData(int index, int offset, net::IOBuffer* buf,
+                         int buf_len) {
+  DCHECK(init_);
+  if (InvalidStream(index))
+    return net::ERR_INVALID_ARGUMENT;
+
+  int stream_size = streams_[index].size;
+  if (offset >= stream_size || offset < 0 || buf_len == 0)
+    return 0;
+  if (offset + buf_len > stream_size)
+    buf_len = stream_size - offset;
+
+  if (OnDisk()) {
+    offset += streams_[index].offset;
+    if (store_->ReadData(id_, buf->data(), buf_len, offset))
+      return buf_len;
+    return net::ERR_FAILED;
+  }
+  memcpy(buf->data(), &streams_[index].write_buffer[offset], buf_len);
+  return buf_len;
+}
+
+int CacheEntry::WriteData(int index, int offset, net::IOBuffer* buf,
+                          int buf_len) {
+  DCHECK(init_ && !closed_);
+  if (InvalidStream(index))
+    return net::ERR_INVALID_ARGUMENT;
+
+  DCHECK(offset >= 0 && buf_len >= 0);
+  Stream& stream = streams_[index];
+  size_t new_size = static_cast<size_t>(offset + buf_len);
+  if (new_size) {
+    // TODO(agayev): Currently, only append and overwrite is supported.  Add
+    // support for arbitrary writes.
+    DCHECK(!offset || offset == stream.size);
+    if (stream.write_buffer.capacity() < new_size)
+      stream.write_buffer.reserve(new_size);
+    memcpy(&streams_[index].write_buffer[offset], buf->data(), buf_len);
+  }
+  stream.size = new_size;
+  return buf_len;
+}
+
+bool CacheEntry::OnDisk() const {
+  return id_ != -1;
+}
+
+bool CacheEntry::InvalidStream(int stream_index) const {
+  return stream_index < 0 || stream_index >= kFlashCacheEntryNumStreams;
+}
+
+int32 CacheEntry::Size() const {
+  DCHECK(init_);
+  int32 size = kFlashCacheEntryHeaderSize;
+  for (int i = 0; i < kFlashCacheEntryNumStreams; ++i)
+    size += streams_[i].size;
+  DCHECK(size > 0 && size <= kFlashSegmentFreeSpace);
+  return size;
+}
+
+bool CacheEntry::Save() {
+  DCHECK(init_ && !closed_ && !OnDisk());
+  int32 stream_sizes[kFlashCacheEntryNumStreams];
+  COMPILE_ASSERT(sizeof(stream_sizes) == kFlashCacheEntryHeaderSize,
+                 invalid_cache_entry_header_size);
+
+  for (int i = 0; i < kFlashCacheEntryNumStreams; ++i)
+    stream_sizes[i] = streams_[i].size;
+
+  if (!store_->CreateEntry(Size(), &id_))
+    return false;
+  if (!store_->WriteData(stream_sizes, kFlashCacheEntryHeaderSize))
+    return false;
+  for (int i = 0; i < kFlashCacheEntryNumStreams; ++i) {
+    if (!store_->WriteData(&streams_[i].write_buffer[0], streams_[i].size))
+      return false;
+  }
+  store_->CloseEntry(id_);
+  return true;
+}
+
+CacheEntry::Stream::Stream() : offset(0), size(0) {
+}
+
+CacheEntry::Stream::~Stream() {
+}
+
+}  // namespace disk_cache