Disk cache: Update the disk cache tools and tests to use

the new interface (provide a cache thread and callback).

BUG=26730
TEST=unit tests


Review URL: http://codereview.chromium.org/2739007

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@49819 0039d316-1c4b-4281-b951-d872f2087c98

4 files changed, 193 insertions, 85 deletions

diff --git a/net/tools/crash_cache/crash_cache.cc b/net/tools/crash_cache/crash_cache.cc
index 4686d13..a26c873 100644
--- a/net/tools/crash_cache/crash_cache.cc
+++ b/net/tools/crash_cache/crash_cache.cc
@@ -1,4 +1,4 @@
-// Copyright (c) 2006-2008 The Chromium Authors. All rights reserved.
+// Copyright (c) 2006-2010 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.
 
@@ -17,7 +17,9 @@
 #include "base/path_service.h"
 #include "base/process_util.h"
 #include "base/string_util.h"
-
+#include "base/thread.h"
+#include "net/base/net_errors.h"
+#include "net/base/test_completion_callback.h"
 #include "net/disk_cache/backend_impl.h"
 #include "net/disk_cache/disk_cache.h"
 #include "net/disk_cache/disk_cache_test_util.h"
@@ -117,10 +119,14 @@ bool CreateTargetFolder(const FilePath& path, RankCrashes action,
 }
 
 // Generates the files for an empty and one item cache.
-int SimpleInsert(const FilePath& path, RankCrashes action) {
-  disk_cache::Backend* cache = disk_cache::CreateCacheBackend(path, false, 0,
-                                                              net::DISK_CACHE);
-  if (!cache || cache->GetEntryCount())
+int SimpleInsert(const FilePath& path, RankCrashes action,
+                 base::Thread* cache_thread) {
+  TestCompletionCallback cb;
+  disk_cache::Backend* cache;
+  int rv = disk_cache::CreateCacheBackend(net::DISK_CACHE, path, 0, false,
+                                          cache_thread->message_loop_proxy(),
+                                          &cache, &cb);
+  if (cb.GetResult(rv) != net::OK || cache->GetEntryCount())
     return GENERIC;
 
   const char* test_name = "some other key";
@@ -131,7 +137,8 @@ int SimpleInsert(const FilePath& path, RankCrashes action) {
   }
 
   disk_cache::Entry* entry;
-  if (!cache->CreateEntry(test_name, &entry))
+  rv = cache->CreateEntry(test_name, &entry, &cb);
+  if (cb.GetResult(rv) != net::OK)
     return GENERIC;
 
   entry->Close();
@@ -140,36 +147,44 @@ int SimpleInsert(const FilePath& path, RankCrashes action) {
   g_rankings_crash = action;
   test_name = kCrashEntryName;
 
-  if (!cache->CreateEntry(test_name, &entry))
+  rv = cache->CreateEntry(test_name, &entry, &cb);
+  if (cb.GetResult(rv) != net::OK)
     return GENERIC;
 
   return NOT_REACHED;
 }
 
 // Generates the files for a one item cache, and removing the head.
-int SimpleRemove(const FilePath& path, RankCrashes action) {
+int SimpleRemove(const FilePath& path, RankCrashes action,
+                 base::Thread* cache_thread) {
   DCHECK(action >= disk_cache::REMOVE_ONE_1);
   DCHECK(action <= disk_cache::REMOVE_TAIL_3);
 
-  disk_cache::Backend* cache = disk_cache::CreateCacheBackend(path, false, 0,
-                                                              net::DISK_CACHE);
-  if (!cache || cache->GetEntryCount())
+  TestCompletionCallback cb;
+  disk_cache::Backend* cache;
+  int rv = disk_cache::CreateCacheBackend(net::DISK_CACHE, path, 0, false,
+                                          cache_thread->message_loop_proxy(),
+                                          &cache, &cb);
+  if (cb.GetResult(rv) != net::OK || cache->GetEntryCount())
     return GENERIC;
 
   disk_cache::Entry* entry;
-  if (!cache->CreateEntry(kCrashEntryName, &entry))
+  rv = cache->CreateEntry(kCrashEntryName, &entry, &cb);
+  if (cb.GetResult(rv) != net::OK)
     return GENERIC;
 
   entry->Close();
 
   if (action >= disk_cache::REMOVE_TAIL_1) {
-    if (!cache->CreateEntry("some other key", &entry))
+    rv = cache->CreateEntry("some other key", &entry, &cb);
+    if (cb.GetResult(rv) != net::OK)
       return GENERIC;
 
     entry->Close();
   }
 
-  if (!cache->OpenEntry(kCrashEntryName, &entry))
+  rv = cache->OpenEntry(kCrashEntryName, &entry, &cb);
+  if (cb.GetResult(rv) != net::OK)
     return GENERIC;
 
   g_rankings_crash = action;
@@ -179,26 +194,33 @@ int SimpleRemove(const FilePath& path, RankCrashes action) {
   return NOT_REACHED;
 }
 
-int HeadRemove(const FilePath& path, RankCrashes action) {
+int HeadRemove(const FilePath& path, RankCrashes action,
+               base::Thread* cache_thread) {
   DCHECK(action >= disk_cache::REMOVE_HEAD_1);
   DCHECK(action <= disk_cache::REMOVE_HEAD_4);
 
-  disk_cache::Backend* cache = disk_cache::CreateCacheBackend(path, false, 0,
-                                                              net::DISK_CACHE);
-  if (!cache || cache->GetEntryCount())
+  TestCompletionCallback cb;
+  disk_cache::Backend* cache;
+  int rv = disk_cache::CreateCacheBackend(net::DISK_CACHE, path, 0, false,
+                                          cache_thread->message_loop_proxy(),
+                                          &cache, &cb);
+  if (cb.GetResult(rv) != net::OK || cache->GetEntryCount())
     return GENERIC;
 
   disk_cache::Entry* entry;
-  if (!cache->CreateEntry("some other key", &entry))
+  rv = cache->CreateEntry("some other key", &entry, &cb);
+  if (cb.GetResult(rv) != net::OK)
     return GENERIC;
 
   entry->Close();
-  if (!cache->CreateEntry(kCrashEntryName, &entry))
+  rv = cache->CreateEntry(kCrashEntryName, &entry, &cb);
+  if (cb.GetResult(rv) != net::OK)
     return GENERIC;
 
   entry->Close();
 
-  if (!cache->OpenEntry(kCrashEntryName, &entry))
+  rv = cache->OpenEntry(kCrashEntryName, &entry, &cb);
+  if (cb.GetResult(rv) != net::OK)
     return GENERIC;
 
   g_rankings_crash = action;
@@ -209,27 +231,34 @@ int HeadRemove(const FilePath& path, RankCrashes action) {
 }
 
 // Generates the files for insertion and removals on heavy loaded caches.
-int LoadOperations(const FilePath& path, RankCrashes action) {
+int LoadOperations(const FilePath& path, RankCrashes action,
+                   base::Thread* cache_thread) {
   DCHECK(action >= disk_cache::INSERT_LOAD_1);
 
-  // Work with a tiny index table (16 entries)
-  disk_cache::BackendImpl* cache =
-      new disk_cache::BackendImpl(path, 0xf);
-  if (!cache || !cache->SetMaxSize(0x100000) || !cache->Init() ||
-      cache->GetEntryCount())
+  // Work with a tiny index table (16 entries).
+  disk_cache::BackendImpl* cache = new disk_cache::BackendImpl(
+      path, 0xf, cache_thread->message_loop_proxy());
+  if (!cache || !cache->SetMaxSize(0x100000))
+    return GENERIC;
+
+  if (!cache->Init() || cache->GetEntryCount())
     return GENERIC;
 
   int seed = static_cast<int>(Time::Now().ToInternalValue());
   srand(seed);
 
+  TestCompletionCallback cb;
+  int rv;
   disk_cache::Entry* entry;
   for (int i = 0; i < 100; i++) {
     std::string key = GenerateKey(true);
-    if (!cache->CreateEntry(key, &entry))
+    rv = cache->CreateEntry(key, &entry, &cb);
+    if (cb.GetResult(rv) != net::OK)
       return GENERIC;
     entry->Close();
     if (50 == i && action >= disk_cache::REMOVE_LOAD_1) {
-      if (!cache->CreateEntry(kCrashEntryName, &entry))
+      rv = cache->CreateEntry(kCrashEntryName, &entry, &cb);
+      if (cb.GetResult(rv) != net::OK)
         return GENERIC;
       entry->Close();
     }
@@ -238,11 +267,13 @@ int LoadOperations(const FilePath& path, RankCrashes action) {
   if (action <= disk_cache::INSERT_LOAD_2) {
     g_rankings_crash = action;
 
-    if (!cache->CreateEntry(kCrashEntryName, &entry))
+    rv = cache->CreateEntry(kCrashEntryName, &entry, &cb);
+    if (cb.GetResult(rv) != net::OK)
       return GENERIC;
   }
 
-  if (!cache->OpenEntry(kCrashEntryName, &entry))
+  rv = cache->OpenEntry(kCrashEntryName, &entry, &cb);
+  if (cb.GetResult(rv) != net::OK)
     return GENERIC;
 
   g_rankings_crash = action;
@@ -255,7 +286,7 @@ int LoadOperations(const FilePath& path, RankCrashes action) {
 
 // Main function on the child process.
 int SlaveCode(const FilePath& path, RankCrashes action) {
-  MessageLoop message_loop;
+  MessageLoopForIO message_loop;
 
   FilePath full_path;
   if (!CreateTargetFolder(path, action, &full_path)) {
@@ -263,23 +294,28 @@ int SlaveCode(const FilePath& path, RankCrashes action) {
     return CRASH_OVERWRITE;
   }
 
+  base::Thread cache_thread("CacheThread");
+  if (!cache_thread.StartWithOptions(
+          base::Thread::Options(MessageLoop::TYPE_IO, 0)))
+    return GENERIC;
+
   if (action <= disk_cache::INSERT_ONE_3)
-    return SimpleInsert(full_path, action);
+    return SimpleInsert(full_path, action, &cache_thread);
 
   if (action <= disk_cache::INSERT_LOAD_2)
-    return LoadOperations(full_path, action);
+    return LoadOperations(full_path, action, &cache_thread);
 
   if (action <= disk_cache::REMOVE_ONE_4)
-    return SimpleRemove(full_path, action);
+    return SimpleRemove(full_path, action, &cache_thread);
 
   if (action <= disk_cache::REMOVE_HEAD_4)
-    return HeadRemove(full_path, action);
+    return HeadRemove(full_path, action, &cache_thread);
 
   if (action <= disk_cache::REMOVE_TAIL_3)
-    return SimpleRemove(full_path, action);
+    return SimpleRemove(full_path, action, &cache_thread);
 
   if (action <= disk_cache::REMOVE_LOAD_3)
-    return LoadOperations(full_path, action);
+    return LoadOperations(full_path, action, &cache_thread);
 
   return NOT_REACHED;
 }
diff --git a/net/tools/dump_cache/cache_dumper.cc b/net/tools/dump_cache/cache_dumper.cc
index 74f1482..71720af 100644
--- a/net/tools/dump_cache/cache_dumper.cc
+++ b/net/tools/dump_cache/cache_dumper.cc
@@ -16,10 +16,10 @@ bool CacheDumper::CreateEntry(const std::string& key,
   return cache_->CreateEntry(key, entry);
 }
 
-bool CacheDumper::WriteEntry(disk_cache::Entry* entry, int index, int offset,
-                             net::IOBuffer* buf, int buf_len) {
-  int written = entry->WriteData(index, offset, buf, buf_len, NULL, false);
-  return written == buf_len;
+int CacheDumper::WriteEntry(disk_cache::Entry* entry, int index, int offset,
+                            net::IOBuffer* buf, int buf_len,
+                            net::CompletionCallback* callback) {
+  return entry->WriteData(index, offset, buf, buf_len, callback, false);
 }
 
 void CacheDumper::CloseEntry(disk_cache::Entry* entry, base::Time last_used,
@@ -48,7 +48,7 @@ bool SafeCreateDirectory(const std::wstring& path) {
     pos = 4;
 
   // Create the subdirectories individually
-  while((pos = path.find(backslash, pos)) != std::wstring::npos) {
+  while ((pos = path.find(backslash, pos)) != std::wstring::npos) {
     std::wstring subdir = path.substr(0, pos);
     CreateDirectoryW(subdir.c_str(), NULL);
     // we keep going even if directory creation failed.
@@ -141,10 +141,11 @@ void GetNormalizedHeaders(const net::HttpResponseInfo& info,
   output->append("\r\n");
 }
 
-bool DiskDumper::WriteEntry(disk_cache::Entry* entry, int index, int offset,
-                            net::IOBuffer* buf, int buf_len) {
+int DiskDumper::WriteEntry(disk_cache::Entry* entry, int index, int offset,
+                           net::IOBuffer* buf, int buf_len,
+                           net::CompletionCallback* callback) {
   if (!entry_)
-    return false;
+    return 0;
 
   std::string headers;
   const char *data;
@@ -154,11 +155,11 @@ bool DiskDumper::WriteEntry(disk_cache::Entry* entry, int index, int offset,
     bool truncated;
     if (!net::HttpCache::ParseResponseInfo(buf->data(), buf_len,
                                            &response_info, &truncated))
-      return false;
+      return 0;
 
     // Skip this entry if it was truncated (results in an empty file).
     if (truncated)
-      return true;
+      return buf_len;
 
     // Remove the size headers.
     response_info.headers->RemoveHeader("transfer-encoding");
@@ -188,11 +189,12 @@ bool DiskDumper::WriteEntry(disk_cache::Entry* entry, int index, int offset,
   }
 #ifdef WIN32_LARGE_FILENAME_SUPPORT
   DWORD bytes;
-  DWORD rv = WriteFile(entry_, data, len, &bytes, 0);
-  return rv == TRUE && bytes == static_cast<DWORD>(len);
+  if (!WriteFile(entry_, data, len, &bytes, 0))
+    return 0;
+
+  return bytes;
 #else
-  int bytes = fwrite(data, 1, len, entry_);
-  return bytes == len;
+  return fwrite(data, 1, len, entry_);
 #endif
 }
 
diff --git a/net/tools/dump_cache/cache_dumper.h b/net/tools/dump_cache/cache_dumper.h
index 916b1b4..1af8573 100644
--- a/net/tools/dump_cache/cache_dumper.h
+++ b/net/tools/dump_cache/cache_dumper.h
@@ -1,9 +1,9 @@
-// Copyright (c) 2009 The Chromium Authors. All rights reserved.
+// Copyright (c) 2010 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.
 
-#ifndef NET_TOOLS_DUMP_CACHE_DUMPER_H_
-#define NET_TOOLS_DUMP_CACHE_DUMPER_H_
+#ifndef NET_TOOLS_DUMP_CACHE_CACHE_DUMPER_H_
+#define NET_TOOLS_DUMP_CACHE_CACHE_DUMPER_H_
 
 #include <string>
 #include "base/file_path.h"
@@ -22,6 +22,8 @@
 // An abstract class for writing cache dump data.
 class CacheDumpWriter {
  public:
+  virtual ~CacheDumpWriter() {}
+
   // Creates an entry to be written.
   // On success, populates the |entry|.
   // Returns true on success, false otherwise.
@@ -30,8 +32,9 @@ class CacheDumpWriter {
 
   // Write to the current entry.
   // Returns true on success, false otherwise.
-  virtual bool WriteEntry(disk_cache::Entry* entry, int stream, int offset,
-                          net::IOBuffer* buf, int buf_len) = 0;
+  virtual int WriteEntry(disk_cache::Entry* entry, int stream, int offset,
+                         net::IOBuffer* buf, int buf_len,
+                         net::CompletionCallback* callback) = 0;
 
   // Close the current entry.
   virtual void CloseEntry(disk_cache::Entry* entry, base::Time last_used,
@@ -41,27 +44,29 @@ class CacheDumpWriter {
 // Writes data to a cache.
 class CacheDumper : public CacheDumpWriter {
  public:
-  CacheDumper(disk_cache::BackendImpl* cache) : cache_(cache) {};
+  explicit CacheDumper(disk_cache::Backend* cache) : cache_(cache) {}
 
   virtual bool CreateEntry(const std::string& key, disk_cache::Entry** entry);
-  virtual bool WriteEntry(disk_cache::Entry* entry, int stream, int offset,
-                          net::IOBuffer* buf, int buf_len);
+  virtual int WriteEntry(disk_cache::Entry* entry, int stream, int offset,
+                         net::IOBuffer* buf, int buf_len,
+                         net::CompletionCallback* callback);
   virtual void CloseEntry(disk_cache::Entry* entry, base::Time last_used,
                           base::Time last_modified);
 
  private:
-  disk_cache::BackendImpl* cache_;
+  disk_cache::Backend* cache_;
 };
 
 // Writes data to a disk.
 class DiskDumper : public CacheDumpWriter {
  public:
-  DiskDumper(const std::wstring& path) : path_(path), entry_(NULL) {
+  explicit DiskDumper(const std::wstring& path) : path_(path), entry_(NULL) {
     file_util::CreateDirectory(FilePath(path));
-  };
+  }
   virtual bool CreateEntry(const std::string& key, disk_cache::Entry** entry);
-  virtual bool WriteEntry(disk_cache::Entry* entry, int stream, int offset,
-                          net::IOBuffer* buf, int buf_len);
+  virtual int WriteEntry(disk_cache::Entry* entry, int stream, int offset,
+                         net::IOBuffer* buf, int buf_len,
+                         net::CompletionCallback* callback);
   virtual void CloseEntry(disk_cache::Entry* entry, base::Time last_used,
                           base::Time last_modified);
 
@@ -79,4 +84,4 @@ class DiskDumper : public CacheDumpWriter {
 #endif
 };
 
-#endif  // NET_TOOLS_DUMP_CACHE_DUMPER_H_
+#endif  // NET_TOOLS_DUMP_CACHE_CACHE_DUMPER_H_
diff --git a/net/tools/dump_cache/upgrade.cc b/net/tools/dump_cache/upgrade.cc
index 71031dc..4f565fe 100644
--- a/net/tools/dump_cache/upgrade.cc
+++ b/net/tools/dump_cache/upgrade.cc
@@ -7,8 +7,10 @@
 #include "base/message_loop.h"
 #include "base/scoped_ptr.h"
 #include "base/string_util.h"
+#include "base/thread.h"
 #include "googleurl/src/gurl.h"
 #include "net/base/io_buffer.h"
+#include "net/base/test_completion_callback.h"
 #include "net/disk_cache/backend_impl.h"
 #include "net/disk_cache/entry_impl.h"
 #include "net/http/http_cache.h"
@@ -109,7 +111,7 @@ enum {
 
 class BaseSM : public MessageLoopForIO::IOHandler {
  public:
-  BaseSM(HANDLE channel);
+  explicit BaseSM(HANDLE channel);
   virtual ~BaseSM();
 
  protected:
@@ -128,11 +130,14 @@ class BaseSM : public MessageLoopForIO::IOHandler {
   scoped_array<char> out_buffer_;
   IoBuffer* input_;
   IoBuffer* output_;
+  base::Thread cache_thread_;
+
   DISALLOW_COPY_AND_ASSIGN(BaseSM);
 };
 
 BaseSM::BaseSM(HANDLE channel)
-      : entry_(NULL), channel_(channel), state_(0), pending_count_(0) {
+      : entry_(NULL), channel_(channel), state_(0), pending_count_(0),
+        cache_thread_("cache") {
   in_buffer_.reset(new char[kChannelSize]);
   out_buffer_.reset(new char[kChannelSize]);
   input_ = reinterpret_cast<IoBuffer*>(in_buffer_.get());
@@ -143,6 +148,8 @@ BaseSM::BaseSM(HANDLE channel)
   in_context_.handler = this;
   out_context_.handler = this;
   MessageLoopForIO::current()->RegisterIOHandler(channel_, this);
+  CHECK(cache_thread_.StartWithOptions(
+            base::Thread::Options(MessageLoop::TYPE_IO, 0)));
 }
 
 BaseSM::~BaseSM() {
@@ -200,8 +207,10 @@ bool BaseSM::IsPending() {
 
 class MasterSM : public BaseSM {
  public:
-   MasterSM(const std::wstring& path, HANDLE channel, bool dump_to_disk)
-      : BaseSM(channel), path_(path), dump_to_disk_(dump_to_disk) {
+  MasterSM(const std::wstring& path, HANDLE channel, bool dump_to_disk)
+      : BaseSM(channel), path_(path), dump_to_disk_(dump_to_disk),
+        ALLOW_THIS_IN_INITIALIZER_LIST(
+            write_callback_(this, &MasterSM::DoReadDataComplete)) {
   }
   virtual ~MasterSM() {
     delete writer_;
@@ -233,6 +242,7 @@ class MasterSM : public BaseSM {
   void CloseEntry();
   void SendReadData();
   void DoReadData(int bytes_read);
+  void DoReadDataComplete(int ret);
   void SendQuit();
   void DoEnd();
   void Fail();
@@ -244,10 +254,12 @@ class MasterSM : public BaseSM {
   int bytes_remaining_;
   int offset_;
   int copied_entries_;
-  scoped_ptr<disk_cache::BackendImpl> cache_;
+  int read_size_;
+  scoped_ptr<disk_cache::Backend> cache_;
   CacheDumpWriter* writer_;
   const std::wstring& path_;
   bool dump_to_disk_;
+  net::CompletionCallbackImpl<MasterSM> write_callback_;
 };
 
 void MasterSM::OnIOCompleted(MessageLoopForIO::IOContext* context,
@@ -302,11 +314,18 @@ bool MasterSM::DoInit() {
   if (dump_to_disk_) {
     writer_ = new DiskDumper(path_);
   } else {
-    cache_.reset(new disk_cache::BackendImpl(FilePath::FromWStringHack(path_)));
-    if (!cache_->Init()) {
+    disk_cache::Backend* cache;
+    TestCompletionCallback cb;
+    int rv = disk_cache::CreateCacheBackend(net::DISK_CACHE,
+                                            FilePath::FromWStringHack(path_), 0,
+                                            false,
+                                            cache_thread_.message_loop_proxy(),
+                                            &cache, &cb);
+    if (cb.GetResult(rv) != net::OK) {
       printf("Unable to initialize new files\n");
       return false;
     }
+    cache_.reset(cache);
     writer_ = new CacheDumper(cache_.get());
   }
   if (!writer_)
@@ -474,7 +493,15 @@ void MasterSM::DoReadData(int bytes_read) {
 
   scoped_refptr<net::WrappedIOBuffer> buf =
       new net::WrappedIOBuffer(input_->buffer);
-  if (!writer_->WriteEntry(entry_, stream_, offset_, buf, read_size))
+  int rv = writer_->WriteEntry(entry_, stream_, offset_, buf, read_size,
+                               &write_callback_);
+  if (rv == net::ERR_IO_PENDING) {
+    // We'll continue in DoReadDataComplete.
+    read_size_ = read_size;
+    return;
+  }
+
+  if (rv <= 0)
     return Fail();
 
   offset_ += read_size;
@@ -483,6 +510,16 @@ void MasterSM::DoReadData(int bytes_read) {
   SendReadData();
 }
 
+void MasterSM::DoReadDataComplete(int ret) {
+  if (ret != read_size_)
+    return Fail();
+
+  offset_ += ret;
+  bytes_remaining_ -= ret;
+  // Read some more.
+  SendReadData();
+}
+
 void MasterSM::SendQuit() {
   DEBUGMSG("Master SendQuit\n");
   state_ = MASTER_END;
@@ -508,15 +545,7 @@ void MasterSM::Fail() {
 
 class SlaveSM : public BaseSM {
  public:
-  SlaveSM(const std::wstring& path, HANDLE channel)
-      : BaseSM(channel), iterator_(NULL) {
-    cache_.reset(new disk_cache::BackendImpl(FilePath::FromWStringHack(path)));
-    if (!cache_->Init()) {
-      printf("Unable to open cache files\n");
-      return;
-    }
-    cache_->SetUpgradeMode();
-  }
+  SlaveSM(const std::wstring& path, HANDLE channel);
   virtual ~SlaveSM();
 
   bool DoInit();
@@ -538,14 +567,36 @@ class SlaveSM : public BaseSM {
   void DoGetUseTimes();
   void DoGetDataSize();
   void DoReadData();
+  void DoReadDataComplete(int ret);
   void DoEnd();
   void Fail();
 
   void* iterator_;
+  Message msg_;  // Only used for DoReadDataComplete.
 
+  net::CompletionCallbackImpl<SlaveSM> read_callback_;
   scoped_ptr<disk_cache::BackendImpl> cache_;
 };
 
+SlaveSM::SlaveSM(const std::wstring& path, HANDLE channel)
+    : BaseSM(channel), iterator_(NULL),
+      ALLOW_THIS_IN_INITIALIZER_LIST(
+          read_callback_(this, &SlaveSM::DoReadDataComplete)) {
+  disk_cache::Backend* cache;
+  TestCompletionCallback cb;
+  int rv = disk_cache::CreateCacheBackend(net::DISK_CACHE,
+                                          FilePath::FromWStringHack(path), 0,
+                                          false,
+                                          cache_thread_.message_loop_proxy(),
+                                          &cache, &cb);
+  if (cb.GetResult(rv) != net::OK) {
+    printf("Unable to open cache files\n");
+    return;
+  }
+  cache_.reset(reinterpret_cast<disk_cache::BackendImpl*>(cache));
+  cache_->SetUpgradeMode();
+}
+
 SlaveSM::~SlaveSM() {
   if (iterator_)
     cache_->EndEnumeration(&iterator_);
@@ -753,7 +804,13 @@ void SlaveSM::DoReadData() {
   } else {
     scoped_refptr<net::WrappedIOBuffer> buf =
         new net::WrappedIOBuffer(output_->buffer);
-    int ret = entry_->ReadData(stream, input_->msg.arg3, buf, size, NULL);
+    int ret = entry_->ReadData(stream, input_->msg.arg3, buf, size,
+                               &read_callback_);
+    if (ret == net::ERR_IO_PENDING) {
+      // Save the message so we can continue were we left.
+      msg_ = msg;
+      return;
+    }
 
     msg.buffer_bytes = (ret < 0) ? 0 : ret;
     msg.result = RESULT_OK;
@@ -761,6 +818,14 @@ void SlaveSM::DoReadData() {
   SendMsg(msg);
 }
 
+void SlaveSM::DoReadDataComplete(int ret) {
+  DEBUGMSG("\t\t\tSlave DoReadDataComplete\n");
+  DCHECK_EQ(READ_DATA, msg_.command);
+  msg_.buffer_bytes = (ret < 0) ? 0 : ret;
+  msg_.result = RESULT_OK;
+  SendMsg(msg_);
+}
+
 void SlaveSM::DoEnd() {
   DEBUGMSG("\t\t\tSlave DoEnd\n");
   MessageLoop::current()->PostTask(FROM_HERE, new MessageLoop::QuitTask());