Implement async verision of FileSystemFileUtil and in-memory file system for testing purposes.

patch from issue 8574007

BUG=chromium-os:23316
TEST=out/Debug/test_shell_tests --gtest_filter='MemoryFileUtilTest.*'


Review URL: http://codereview.chromium.org/8907014

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@114923 0039d316-1c4b-4281-b951-d872f2087c98

6 files changed, 1743 insertions, 0 deletions

diff --git a/webkit/chromeos/OWNERS b/webkit/chromeos/OWNERS
new file mode 100644
index 0000000..427afde
--- /dev/null
+++ b/webkit/chromeos/OWNERS
@@ -0,0 +1,3 @@
+kinuko@chromium.org
+satorux@chromium.org
+zelidrag@chromium.org
diff --git a/webkit/chromeos/fileapi/async_file_stream.h b/webkit/chromeos/fileapi/async_file_stream.h
new file mode 100644
index 0000000..ef0eeed
--- /dev/null
+++ b/webkit/chromeos/fileapi/async_file_stream.h
@@ -0,0 +1,56 @@
+// Copyright (c) 2011 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 WEBKIT_CHROMEOS_FILEAPI_ASYNC_FILE_STREAM_H_
+#define WEBKIT_CHROMEOS_FILEAPI_ASYNC_FILE_STREAM_H_
+
+#include "base/callback.h"
+#include "base/platform_file.h"
+
+namespace fileapi {
+
+using base::PlatformFileError;
+
+// This class is used for implementing Open() in FileUtilAsync. This class
+// is similar to net::FileStream, but supporting only the asynchronous
+// operations and not necessarily relying on PlatformFile.
+class AsyncFileStream {
+ public:
+  // Used for Read() and Write(). |result| is the return code of the
+  // operation, and |length| is the length of data read or written.
+  typedef base::Callback<void(PlatformFileError result,
+                              int64 length)> ReadWriteCallback;
+
+  // Used for Seek(). |result| is the return code of the operation.
+  typedef base::Callback<void(PlatformFileError)> SeekCallback;
+
+  virtual ~AsyncFileStream() {};
+
+  // Reads data from the current stream position. Up to |length| bytes
+  // will be read from |buffer|. The memory pointed to by |buffer| must
+  // remain valid until the callback is called. On success,
+  // PLATFORM_FILE_OK is passed to |callback| with the number of bytes
+  // read. On failure, an error code is passed instead.
+  virtual void Read(char* buffer,
+                    int64 length,
+                    const ReadWriteCallback& callback) = 0;
+
+  // Writes data at the current stream position. Up to |length| bytes will
+  // be written from |buffer|. The memory pointed to by |buffer| must
+  // remain valid until the callback is called. On success,
+  // PLATFORM_FILE_OK is passed to |callback| with the number of bytes
+  // written. On failure, an error code is passed instead.
+  virtual void Write(const char* buffer,
+                     int64 length,
+                     const ReadWriteCallback& callback) = 0;
+
+  // Moves the stream position. On success, PLATFORM_FILE_OK is passed to
+  // |callback|. On error, an error code is passed instead.
+  virtual void Seek(int64 offset,
+                    const SeekCallback& callback) = 0;
+};
+
+}  // namespace fileapi
+
+#endif  // WEBKIT_CHROMEOS_FILEAPI_ASYNC_FILE_STREAM_H_
diff --git a/webkit/chromeos/fileapi/file_util_async.h b/webkit/chromeos/fileapi/file_util_async.h
new file mode 100644
index 0000000..58cb2b1
--- /dev/null
+++ b/webkit/chromeos/fileapi/file_util_async.h
@@ -0,0 +1,123 @@
+// Copyright (c) 2011 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 WEBKIT_CHROMEOS_FILEAPI_FILE_SYSTEM_FILE_UTIL_ASYNC_H_
+#define WEBKIT_CHROMEOS_FILEAPI_FILE_SYSTEM_FILE_UTIL_ASYNC_H_
+
+#include "base/callback.h"
+#include "base/file_util_proxy.h"
+#include "base/platform_file.h"
+#include "webkit/chromeos/fileapi/async_file_stream.h"
+
+namespace fileapi {
+
+using base::PlatformFileError;
+
+// The interface class of asynchronous file utils. All functions are pure
+// virtual.
+class FileUtilAsync {
+ public:
+  virtual ~FileUtilAsync() {}
+
+  typedef base::FileUtilProxy::Entry DirectoryEntry;
+
+  // Used for GetFileInfo(). |result| is the return code of the operation,
+  // and |file_info| is the obtained file info.
+  typedef base::Callback<void(
+      PlatformFileError result,
+      const base::PlatformFileInfo& file_info)> GetFileInfoCallback;
+
+  // Used for Create(), etc. |result| is the return code of the operation.
+  typedef base::Callback<void(PlatformFileError)> StatusCallback;
+
+  // Used for Open(). |result| is the return code of the operation, and
+  // |stream| is the stream of the opened file.
+  typedef base::Callback<void(
+      PlatformFileError result,
+      AsyncFileStream* stream)> OpenCallback;
+
+  typedef std::vector<DirectoryEntry> FileList;
+
+  // Used for ReadDirectoryCallback(). |result| is the return code of the
+  // operation, |file_list| is the list of files read, and |completed| is
+  // true if all files are read.
+  typedef base::Callback<void(
+      PlatformFileError result,
+      const FileList& file_list,
+      bool completed)> ReadDirectoryCallback;
+
+  // Opens a file of the given |file_path| with |flags|. On success,
+  // PLATFORM_FILE_OK is passed to |callback| with a pointer to newly
+  // created AsyncFileStream object. The caller should delete the
+  // stream. On failure, an error code is passed instead.
+  virtual void Open(const FilePath& file_path,
+                    int file_flags,  // PlatformFileFlags
+                    const OpenCallback& callback) = 0;
+
+  // Gets file info of the given |file_path|. On success,
+  // PLATFORM_FILE_OK is passed to |callback| with the the obtained file
+  // info. On failure, an error code is passed instead.
+  virtual void GetFileInfo(const FilePath& file_path,
+                           const GetFileInfoCallback& callback) = 0;
+
+  // Creates a file of the given |file_path|. On success,
+  // PLATFORM_FILE_OK is passed to |callback|. On failure, an error code
+  // is passed instead.
+  virtual void Create(const FilePath& file_path,
+                      const StatusCallback& callback) = 0;
+
+  // Truncates a file of the given |file_path| to |length|. On success,
+  // PLATFORM_FILE_OK is passed to |callback|. On failure, an error code
+  // is passed instead.
+  virtual void Truncate(const FilePath& file_path,
+                        int64 length,
+                        const StatusCallback& callback) = 0;
+
+  // Modifies the timestamps of a file of the given |file_path|. On
+  // success, PLATFORM_FILE_OK is passed to |callback|. On failure, an
+  // error code is passed instead.
+  virtual void Touch(const FilePath& file_path,
+                     const base::Time& last_access_time,
+                     const base::Time& last_modified_time,
+                     const StatusCallback& callback) = 0;
+
+  // Removes a file or directory of the given |file_path|. If |recursive|
+  // is true, removes the contents of the given directory recursively. On
+  // success, PLATFORM_FILE_OK is passed to |callback|. On failure, an
+  // error code is passed instead.
+  virtual void Remove(const FilePath& file_path,
+                      bool recursive,
+                      const StatusCallback& callback) = 0;
+
+  // Creates a directory of the given |dir_path|. On success,
+  // PLATFORM_FILE_OK is passed to |callback|. On failure, an error code
+  // is passed instead.
+  virtual void CreateDirectory(const FilePath& dir_path,
+                               const StatusCallback& callback) = 0;
+
+  // Reads a directory of the given |dir_path|. On success,
+  // PLATFORM_FILE_OK is passed to |callback| with the list of files, and
+  // a boolean value indicating if all files are read. On failure, an
+  // error code is passed instead.
+  //
+  // The ReadDirectoryCallback may be called several times, returning the
+  // portions of the whole directory listing. The reference to vector with
+  // DirectoryEntry objects, passed to callback is guaranteed to contain the
+  // results of the operation only while callback is running.
+  //
+  // The implementations of FileUtilAsync should be careful to populate the
+  // vector on the same thread, on which the callback is called. Otherwise,
+  // if callback is called through PostTask, the data might get overwritten
+  // before callback is actually called.
+  //
+  // TODO(olege): Maybe make it possible to read only a part of the directory.
+  virtual void ReadDirectory(const FilePath& dir_path,
+                             const ReadDirectoryCallback& callback) = 0;
+
+  // TODO(olege): Add LocalCopy and LocalMove.
+};
+
+}  // fileapi
+
+#endif  // WEBKIT_CHROMEOS_FILEAPI_FILE_SYSTEM_FILE_UTIL_ASYNC_H_
diff --git a/webkit/chromeos/fileapi/memory_file_util.cc b/webkit/chromeos/fileapi/memory_file_util.cc
new file mode 100644
index 0000000..2d4d53e
--- /dev/null
+++ b/webkit/chromeos/fileapi/memory_file_util.cc
@@ -0,0 +1,586 @@
+// Copyright (c) 2011 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/bind.h"
+#include "base/memory/weak_ptr.h"
+#include "base/message_loop.h"
+#include "webkit/chromeos/fileapi/memory_file_util.h"
+
+namespace {
+const int kDefaultReadDirectoryBufferSize = 100;
+}  // namespace
+
+namespace fileapi {
+
+// In-memory implementation of AsyncFileStream.
+class MemoryFileUtilAsyncFileStream : public AsyncFileStream {
+ public:
+  // |file_entry| is owned by MemoryFileUtil.
+  MemoryFileUtilAsyncFileStream(MemoryFileUtil::FileEntry* file_entry,
+                                int flags)
+      : file_entry_(file_entry),
+        flags_(flags),
+        offset_(0),
+        weak_ptr_factory_(this) {
+  }
+
+  // AsyncFileStream override.
+  virtual void Read(char* buffer,
+                    int64 length,
+                    const ReadWriteCallback& callback) OVERRIDE {
+    MessageLoop::current()->PostTask(
+        FROM_HERE,
+        base::Bind(&MemoryFileUtilAsyncFileStream::DoRead,
+                   weak_ptr_factory_.GetWeakPtr(),
+                   buffer, length, callback));
+  }
+
+  // AsyncFileStream override.
+  virtual void Write(const char* buffer,
+                     int64 length,
+                     const ReadWriteCallback& callback) OVERRIDE {
+    MessageLoop::current()->PostTask(
+        FROM_HERE,
+        base::Bind(&MemoryFileUtilAsyncFileStream::DoWrite,
+                   weak_ptr_factory_.GetWeakPtr(),
+                   buffer, length, callback));
+  }
+
+  // AsyncFileStream override.
+  virtual void Seek(int64 offset,
+                    const SeekCallback& callback) OVERRIDE {
+    MessageLoop::current()->PostTask(
+        FROM_HERE,
+        base::Bind(&MemoryFileUtilAsyncFileStream::DoSeek,
+                   weak_ptr_factory_.GetWeakPtr(),
+                   offset, callback));
+  }
+
+ private:
+  // Callback used for Read().
+  void DoRead(char* buffer,
+              int64 length,
+              const ReadWriteCallback& callback) {
+
+    if ((flags_ & base::PLATFORM_FILE_READ) == 0) {
+      callback.Run(base::PLATFORM_FILE_ERROR_INVALID_OPERATION, 0);
+      return;
+    }
+
+    // Shorten the length so the read does not overrun.
+    length = std::min(length, file_size() - offset_);
+
+    const std::string& contents = file_entry_->contents;
+    std::copy(contents.begin() + offset_,
+              contents.begin() + offset_ + length,
+              buffer);
+    offset_ += length;
+
+    callback.Run(base::PLATFORM_FILE_OK, length);
+  }
+
+  // Callback used for Write().
+  void DoWrite(const char* buffer,
+               int64 length,
+               const ReadWriteCallback& callback) {
+    if ((flags_ & base::PLATFORM_FILE_WRITE) == 0) {
+      callback.Run(base::PLATFORM_FILE_ERROR_INVALID_OPERATION, 0);
+      return;
+    }
+
+    // Extend the contents if needed.
+    std::string* contents = &file_entry_->contents;
+    if (offset_ + length > file_size())
+      contents->resize(offset_ + length, 0);  // Fill with 0.
+
+    std::copy(buffer, buffer + length,
+              contents->begin() + offset_);
+    file_entry_->last_modified = base::Time::Now();
+    offset_ += length;
+
+    callback.Run(base::PLATFORM_FILE_OK, length);
+  }
+
+  // Callback used for Seek().
+  void DoSeek(int64 offset,
+              const SeekCallback& callback) {
+    if (offset > file_size()) {
+      // Unlike lseek(2), we don't allow an offset larger than the file
+      // size for this file implementation.
+      callback.Run(base::PLATFORM_FILE_ERROR_INVALID_OPERATION);
+      return;
+    }
+
+    offset_ = offset;
+    callback.Run(base::PLATFORM_FILE_OK);
+  }
+
+  // Returns the file size as int64.
+  int64 file_size() const {
+    return static_cast<int64>(file_entry_->contents.size());
+  }
+
+  MemoryFileUtil::FileEntry* file_entry_;
+  const int flags_;
+  int64 offset_;
+  base::WeakPtrFactory<MemoryFileUtilAsyncFileStream> weak_ptr_factory_;
+};
+
+MemoryFileUtil::FileEntry::FileEntry()
+    : is_directory(false) {
+}
+
+MemoryFileUtil::FileEntry::~FileEntry() {
+}
+
+MemoryFileUtil::MemoryFileUtil(const FilePath& root_path)
+    : read_directory_buffer_size_(kDefaultReadDirectoryBufferSize) {
+  FileEntry root;
+  root.is_directory = true;
+  root.last_modified = base::Time::Now();
+
+  files_[root_path] = root;
+}
+
+MemoryFileUtil::~MemoryFileUtil() {
+}
+
+// Depending on the flags value the flow of file opening will be one of
+// the following:
+//
+// PLATFORM_FILE_OPEN:
+// - GetFileInfo
+// - DidGetFileInfoForOpen
+// - OpenVerifiedFile
+//
+// PLATFORM_FILE_CREATE:
+// - Create
+// - DidCreateOrTruncateForOpen
+// - OpenVerifiedFile
+//
+// PLATFORM_FILE_OPEN_ALWAYS:
+// - GetFileInfo
+// - DidGetFileInfoForOpen
+// - OpenVerifiedFile   OR   Create
+//                           DidCreateOrTruncateForOpen
+//                           OpenVerifiedFile
+//
+// PLATFORM_FILE_CREATE_ALWAYS:
+// - Truncate
+// - OpenTruncatedFileOrCreate
+// - OpenVerifiedFile   OR   Create
+//                           DidCreateOrTruncateForOpen
+//                           OpenVerifiedFile
+//
+// PLATFORM_FILE_OPEN_TRUNCATED:
+// - Truncate
+// - DidCreateOrTruncateForOpen
+// - OpenVerifiedFile
+//
+void MemoryFileUtil::Open(
+    const FilePath& file_path,
+    int flags,
+    const OpenCallback& callback) {
+  int create_flag = flags & (base::PLATFORM_FILE_OPEN |
+                             base::PLATFORM_FILE_CREATE |
+                             base::PLATFORM_FILE_OPEN_ALWAYS |
+                             base::PLATFORM_FILE_CREATE_ALWAYS |
+                             base::PLATFORM_FILE_OPEN_TRUNCATED);
+  switch (create_flag) {
+    case base::PLATFORM_FILE_OPEN:
+    case base::PLATFORM_FILE_OPEN_ALWAYS:
+      GetFileInfo(
+          file_path,
+          base::Bind(&MemoryFileUtil::DidGetFileInfoForOpen,
+                     base::Unretained(this), file_path, flags, callback));
+
+      break;
+
+    case base::PLATFORM_FILE_CREATE:
+      Create(
+          file_path,
+          base::Bind(&MemoryFileUtil::DidCreateOrTruncateForOpen,
+                     base::Unretained(this), file_path, flags, 0, callback));
+      break;
+
+    case base::PLATFORM_FILE_CREATE_ALWAYS:
+      Truncate(
+          file_path,
+          0,
+          base::Bind(&MemoryFileUtil::OpenTruncatedFileOrCreate,
+                     base::Unretained(this), file_path, flags, callback));
+
+    case base::PLATFORM_FILE_OPEN_TRUNCATED:
+      Truncate(
+          file_path,
+          0,
+          base::Bind(&MemoryFileUtil::DidCreateOrTruncateForOpen,
+                     base::Unretained(this), file_path, flags, 0, callback));
+      break;
+
+    default:
+      MessageLoop::current()->PostTask(
+          FROM_HERE,
+          base::Bind(callback,
+                     base::PLATFORM_FILE_ERROR_INVALID_OPERATION,
+                     static_cast<AsyncFileStream*>(NULL)));
+  }
+}
+
+void MemoryFileUtil::GetFileInfo(
+    const FilePath& file_path,
+    const GetFileInfoCallback& callback) {
+  MessageLoop::current()->PostTask(
+      FROM_HERE,
+      base::Bind(&MemoryFileUtil::DoGetFileInfo, base::Unretained(this),
+                 file_path.StripTrailingSeparators(), callback));
+}
+
+void MemoryFileUtil::Create(
+    const FilePath& file_path,
+    const StatusCallback& callback) {
+  MessageLoop::current()->PostTask(
+      FROM_HERE,
+      base::Bind(&MemoryFileUtil::DoCreate, base::Unretained(this),
+                 file_path.StripTrailingSeparators(), false, callback));
+}
+
+void MemoryFileUtil::Truncate(
+    const FilePath& file_path,
+    int64 length,
+    const StatusCallback& callback) {
+  MessageLoop::current()->PostTask(
+      FROM_HERE,
+      base::Bind(&MemoryFileUtil::DoTruncate, base::Unretained(this),
+                 file_path.StripTrailingSeparators(), length, callback));
+}
+
+void MemoryFileUtil::Touch(
+    const FilePath& file_path,
+    const base::Time& last_access_time,
+    const base::Time& last_modified_time,
+    const StatusCallback& callback) {
+  MessageLoop::current()->PostTask(
+      FROM_HERE,
+      base::Bind(&MemoryFileUtil::DoTouch, base::Unretained(this),
+                 file_path.StripTrailingSeparators(),
+                 last_modified_time, callback));
+}
+
+void MemoryFileUtil::Remove(
+    const FilePath& file_path,
+    bool recursive,
+    const StatusCallback& callback) {
+  if (recursive) {
+    MessageLoop::current()->PostTask(
+        FROM_HERE,
+        base::Bind(&MemoryFileUtil::DoRemoveRecursive,
+                   base::Unretained(this), file_path.StripTrailingSeparators(),
+                   callback));
+  } else {
+    MessageLoop::current()->PostTask(
+        FROM_HERE,
+        base::Bind(&MemoryFileUtil::DoRemoveSingleFile,
+                   base::Unretained(this), file_path.StripTrailingSeparators(),
+                   callback));
+  }
+}
+
+void MemoryFileUtil::CreateDirectory(
+    const FilePath& dir_path,
+    const StatusCallback& callback) {
+  MessageLoop::current()->PostTask(
+      FROM_HERE,
+      base::Bind(&MemoryFileUtil::DoCreate,
+                 base::Unretained(this), dir_path.StripTrailingSeparators(),
+                 true, callback));
+}
+
+void MemoryFileUtil::ReadDirectory(
+    const FilePath& dir_path,
+    const ReadDirectoryCallback& callback) {
+  MessageLoop::current()->PostTask(
+      FROM_HERE,
+      base::Bind(&MemoryFileUtil::DoReadDirectory,
+                 base::Unretained(this), dir_path.StripTrailingSeparators(),
+                 FilePath(), callback));
+}
+
+void MemoryFileUtil::DoGetFileInfo(const FilePath& file_path,
+                                   const GetFileInfoCallback& callback) {
+  base::PlatformFileInfo file_info;
+
+  FileIterator file_it = files_.find(file_path);
+
+  if (file_it == files_.end()) {
+    callback.Run(base::PLATFORM_FILE_ERROR_NOT_FOUND, file_info);
+    return;
+  }
+  const FileEntry& file_entry = file_it->second;
+
+  file_info.size = file_entry.contents.size();
+  file_info.is_directory = file_entry.is_directory;
+  file_info.is_symbolic_link = false;
+
+  // In this file system implementation we store only one datetime. Many
+  // popular file systems do the same.
+  file_info.last_modified = file_entry.last_modified;
+  file_info.last_accessed = file_entry.last_modified;
+  file_info.creation_time = file_entry.last_modified;
+
+  callback.Run(base::PLATFORM_FILE_OK, file_info);
+}
+
+void MemoryFileUtil::DoCreate(
+    const FilePath& file_path,
+    bool is_directory,
+    const StatusCallback& callback) {
+  if (FileExists(file_path)) {
+    callback.Run(base::PLATFORM_FILE_ERROR_EXISTS);
+    return;
+  }
+
+  if (!IsDirectory(file_path.DirName())) {
+    callback.Run(base::PLATFORM_FILE_ERROR_FAILED);
+    return;
+  }
+
+  FileEntry file;
+  file.is_directory = is_directory;
+  file.last_modified = base::Time::Now();
+
+  files_[file_path] = file;
+  callback.Run(base::PLATFORM_FILE_OK);
+}
+
+void MemoryFileUtil::DoTruncate(
+    const FilePath& file_path,
+    int64 length,
+    const StatusCallback& callback) {
+  FileIterator file_it = files_.find(file_path);
+  if (file_it == files_.end()) {
+    callback.Run(base::PLATFORM_FILE_ERROR_NOT_FOUND);
+    return;
+  }
+
+  FileEntry& file = file_it->second;
+
+  // Fill the extended part with 0 if |length| is larger than the original
+  // contents size.
+  file.contents.resize(length, 0);
+  callback.Run(base::PLATFORM_FILE_OK);
+}
+
+void MemoryFileUtil::DoTouch(
+    const FilePath& file_path,
+    const base::Time& last_modified_time,
+    const StatusCallback& callback) {
+  FileIterator file_it = files_.find(file_path);
+  if (file_it == files_.end()) {
+    callback.Run(base::PLATFORM_FILE_ERROR_NOT_FOUND);
+    return;
+  }
+
+  FileEntry& file = file_it->second;
+
+  file.last_modified = last_modified_time;
+  callback.Run(base::PLATFORM_FILE_OK);
+}
+
+void MemoryFileUtil::DoRemoveSingleFile(
+    const FilePath& file_path,
+    const StatusCallback& callback) {
+  FileIterator file_it = files_.find(file_path);
+  if (file_it == files_.end()) {
+    callback.Run(base::PLATFORM_FILE_ERROR_NOT_FOUND);
+    return;
+  }
+
+  FileEntry& file = file_it->second;
+  if (file.is_directory) {
+    // Check if the directory is empty. This can be done by checking if
+    // the next file is present under the directory. Note that |files_| is
+    // a map hence the file names are sorted by names.
+    FileIterator tmp_it = file_it;
+    ++tmp_it;
+    if (tmp_it != files_.end() && file_path.IsParent(tmp_it->first)) {
+      callback.Run(base::PLATFORM_FILE_ERROR_NOT_A_FILE);
+      return;
+    }
+  }
+
+  files_.erase(file_it);
+  callback.Run(base::PLATFORM_FILE_OK);
+}
+
+void MemoryFileUtil::DoRemoveRecursive(
+    const FilePath& file_path,
+    const StatusCallback& callback) {
+  FileIterator file_it = files_.find(file_path);
+  if (file_it == files_.end()) {
+    callback.Run(base::PLATFORM_FILE_ERROR_NOT_FOUND);
+    return;
+  }
+
+  FileEntry& file = file_it->second;
+  if (!file.is_directory) {
+    files_.erase(file_it);
+    callback.Run(base::PLATFORM_FILE_OK);
+    return;
+  }
+
+  // Remove the directory itself.
+  files_.erase(file_it++);
+  // Remove files under the directory.
+  while (file_it != files_.end()) {
+    if (file_path.IsParent(file_it->first)) {
+      files_.erase(file_it++);
+    } else {
+      break;
+    }
+  }
+  callback.Run(base::PLATFORM_FILE_OK);
+}
+
+void MemoryFileUtil::DoReadDirectory(
+    const FilePath& dir_path,
+    const FilePath& in_from,
+    const ReadDirectoryCallback& callback) {
+  FilePath from = in_from;
+  read_directory_buffer_.clear();
+
+  if (!FileExists(dir_path)) {
+    callback.Run(base::PLATFORM_FILE_ERROR_NOT_FOUND,
+                 read_directory_buffer_, true);
+    return;
+  }
+
+  if (!IsDirectory(dir_path)) {
+    callback.Run(base::PLATFORM_FILE_ERROR_NOT_A_DIRECTORY,
+                 read_directory_buffer_, true);
+    return;
+  }
+
+  if (from.empty())
+    from = dir_path;
+
+  bool completed = true;
+
+  // Here we iterate over all paths in files_ starting with the prefix |from|.
+  // It is not very efficient in case of a deep tree with many files in
+  // subdirectories. If ever we'll need efficiency from this implementation of
+  // FS, this should be changed.
+  for (ConstFileIterator it = files_.lower_bound(from);
+       it != files_.end();
+       ++it) {
+    if (dir_path == it->first)  // Skip the directory itself.
+      continue;
+    if (!dir_path.IsParent(it->first))  // Not in the directory.
+      break;
+    if (it->first.DirName() != dir_path)  // a file in subdirectory
+      continue;
+
+    if (read_directory_buffer_.size() == read_directory_buffer_size_) {
+      from = it->first;
+      completed = false;
+      break;
+    }
+
+    const FileEntry& file = it->second;
+    DirectoryEntry entry;
+    entry.name = it->first.BaseName().value();
+    entry.is_directory = file.is_directory;
+    entry.size = file.contents.size();
+    entry.last_modified_time = file.last_modified;
+
+    read_directory_buffer_.push_back(entry);
+  }
+
+  callback.Run(base::PLATFORM_FILE_OK, read_directory_buffer_, completed);
+
+  if (!completed) {
+    MessageLoop::current()->PostTask(
+        FROM_HERE,
+        base::Bind(&MemoryFileUtil::DoReadDirectory,
+                   base::Unretained(this), dir_path,
+                   from, callback));
+  }
+}
+
+void MemoryFileUtil::OpenVerifiedFile(
+    const FilePath& file_path,
+    int flags,
+    const OpenCallback& callback) {
+  FileIterator file_it = files_.find(file_path);
+  // The existence of the file is guranteed here.
+  DCHECK(file_it != files_.end());
+
+  FileEntry* file_entry = &file_it->second;
+  callback.Run(base::PLATFORM_FILE_OK,
+               new MemoryFileUtilAsyncFileStream(file_entry, flags));
+}
+
+void MemoryFileUtil::DidGetFileInfoForOpen(
+    const FilePath& file_path,
+    int flags,
+    const OpenCallback& callback,
+    PlatformFileError get_info_result,
+    const base::PlatformFileInfo& file_info) {
+  if (get_info_result == base::PLATFORM_FILE_OK && file_info.is_directory) {
+    callback.Run(base::PLATFORM_FILE_ERROR_NOT_A_FILE, NULL);
+    return;
+  }
+
+  if (get_info_result == base::PLATFORM_FILE_OK) {
+    OpenVerifiedFile(file_path, flags, callback);
+    return;
+  }
+
+  if (get_info_result == base::PLATFORM_FILE_ERROR_NOT_FOUND &&
+      flags & base::PLATFORM_FILE_CREATE_ALWAYS) {
+    Create(file_path,
+           base::Bind(&MemoryFileUtil::DidCreateOrTruncateForOpen,
+                      base::Unretained(this), file_path, flags, 0, callback));
+    return;
+  }
+
+  callback.Run(get_info_result, NULL);
+}
+
+void MemoryFileUtil::OpenTruncatedFileOrCreate(
+    const FilePath& file_path,
+    int flags,
+    const OpenCallback& callback,
+    PlatformFileError result) {
+  if (result == base::PLATFORM_FILE_OK) {
+    OpenVerifiedFile(file_path, flags, callback);
+    return;
+  }
+
+  if (result == base::PLATFORM_FILE_ERROR_NOT_FOUND) {
+    Create(
+        file_path,
+        base::Bind(&MemoryFileUtil::DidCreateOrTruncateForOpen,
+                   base::Unretained(this), file_path, flags, 0, callback));
+    return;
+  }
+
+  callback.Run(result, NULL);
+}
+
+void MemoryFileUtil::DidCreateOrTruncateForOpen(
+    const FilePath& file_path,
+    int flags,
+    int64 size,
+    const OpenCallback& callback,
+    PlatformFileError result) {
+  if (result != base::PLATFORM_FILE_OK) {
+    callback.Run(result, NULL);
+    return;
+  }
+
+  OpenVerifiedFile(file_path, flags, callback);
+}
+
+}  // namespace file_api
diff --git a/webkit/chromeos/fileapi/memory_file_util.h b/webkit/chromeos/fileapi/memory_file_util.h
new file mode 100644
index 0000000..357b934
--- /dev/null
+++ b/webkit/chromeos/fileapi/memory_file_util.h
@@ -0,0 +1,150 @@
+// Copyright (c) 2011 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 WEBKIT_CHROMEOS_FILEAPI_FILE_SYSTEM_FILE_UTIL_MEMORY_H_
+#define WEBKIT_CHROMEOS_FILEAPI_FILE_SYSTEM_FILE_UTIL_MEMORY_H_
+
+#include <map>
+#include <string>
+#include <vector>
+
+#include "base/callback.h"
+#include "base/time.h"
+#include "webkit/chromeos/fileapi/file_util_async.h"
+
+namespace fileapi {
+
+// The in-memory file system. Primarily for the purpose of testing
+// FileUtilAsync.
+class MemoryFileUtil : public FileUtilAsync {
+ public:
+  struct FileEntry {
+    FileEntry();
+    ~FileEntry();
+
+    bool is_directory;
+    std::string contents;
+    base::Time last_modified;
+  };
+
+  MemoryFileUtil(const FilePath& root_path);
+  virtual ~MemoryFileUtil();
+
+  // FileUtilAsync overrides.
+  virtual void Open(const FilePath& file_path,
+                    int file_flags,  // PlatformFileFlags
+                    const OpenCallback& callback) OVERRIDE;
+  virtual void GetFileInfo(const FilePath& file_path,
+                           const GetFileInfoCallback& callback) OVERRIDE;
+  virtual void Create(const FilePath& file_path,
+                      const StatusCallback& callback) OVERRIDE;
+  virtual void Truncate(const FilePath& file_path,
+                        int64 length,
+                        const StatusCallback& callback) OVERRIDE;
+  // This FS ignores last_access_time.
+  virtual void Touch(const FilePath& file_path,
+                     const base::Time& last_access_time,
+                     const base::Time& last_modified_time,
+                     const StatusCallback& callback) OVERRIDE;
+  virtual void Remove(const FilePath& file_path,
+                      bool recursive,
+                      const StatusCallback& callback) OVERRIDE;
+  virtual void CreateDirectory(const FilePath& dir_path,
+                               const StatusCallback& callback) OVERRIDE;
+  virtual void ReadDirectory(const FilePath& dir_path,
+                             const ReadDirectoryCallback& callback) OVERRIDE;
+
+ private:
+  friend class MemoryFileUtilTest;
+
+  typedef std::map<FilePath, FileEntry>::iterator FileIterator;
+  typedef std::map<FilePath, FileEntry>::const_iterator ConstFileIterator;
+
+  // Returns true if the given |file_path| is present in the file system.
+  bool FileExists(const FilePath& file_path) const {
+    return files_.find(file_path) != files_.end();
+  }
+
+  // Returns true if the given |file_path| is present and a directory.
+  bool IsDirectory(const FilePath& file_path) const {
+    ConstFileIterator it = files_.find(file_path);
+    return it != files_.end() && it->second.is_directory;
+  }
+
+  // Callback function used to implement GetFileInfo().
+  void DoGetFileInfo(const FilePath& file_path,
+                     const GetFileInfoCallback& callback);
+
+  // Callback function used to implement Create().
+  void DoCreate(const FilePath& file_path,
+                bool is_directory,
+                const StatusCallback& callback);
+
+  // Callback function used to implement Truncate().
+  void DoTruncate(const FilePath& file_path,
+                  int64 length,
+                  const StatusCallback& callback);
+
+  // Callback function used to implement Touch().
+  void DoTouch(const FilePath& file_path,
+               const base::Time& last_modified_time,
+               const StatusCallback& callback);
+
+  // Callback function used to implement Remove().
+  void DoRemoveSingleFile(const FilePath& file_path,
+                          const StatusCallback& callback);
+
+  // Callback function used to implement Remove().
+  void DoRemoveRecursive(const FilePath& file_path,
+                         const StatusCallback& callback);
+
+  // Will start enumerating with file path |from|. If |from| path is
+  // empty, will start from the beginning.
+  void DoReadDirectory(const FilePath& dir_path,
+                       const FilePath& from,
+                       const ReadDirectoryCallback& callback);
+
+  // Opens a file of the given |file_path| with |flags|. A file is
+  // guaranteed to be present at |file_path|.
+  void OpenVerifiedFile(const FilePath& file_path,
+                        int flags,
+                        const OpenCallback& callback);
+
+  // Callback function used to implement Open().
+  void DidGetFileInfoForOpen(const FilePath& file_path,
+                             int flags,
+                             const OpenCallback& callback,
+                             PlatformFileError get_info_result,
+                             const base::PlatformFileInfo& file_info);
+
+  // Callback function used to implement Open().
+  void OpenTruncatedFileOrCreate(const FilePath& file_path,
+                                 int flags,
+                                 const OpenCallback& callback,
+                                 PlatformFileError result);
+
+  // Callback function used to implement Open().
+  void DidCreateOrTruncateForOpen(const FilePath& file_path,
+                                  int flags,
+                                  int64 size,
+                                  const OpenCallback& callback,
+                                  PlatformFileError result);
+
+  // Sets the read directory size buffer.
+  // Mainly for the purpose of testing.
+  void set_read_directory_buffer_size(size_t size) {
+    read_directory_buffer_size_ = size;
+  }
+
+  // The files in the file system.
+  std::map<FilePath, FileEntry> files_;
+  size_t read_directory_buffer_size_;
+  std::vector<DirectoryEntry> read_directory_buffer_;
+
+  DISALLOW_COPY_AND_ASSIGN(MemoryFileUtil);
+};
+
+}  // fileapi
+
+#endif  // WEBKIT_CHROMEOS_FILEAPI_FILE_SYSTEM_FILE_UTIL_ASYNC_H_
diff --git a/webkit/chromeos/fileapi/memory_file_util_unittest.cc b/webkit/chromeos/fileapi/memory_file_util_unittest.cc
new file mode 100644
index 0000000..8e991b00f
--- /dev/null
+++ b/webkit/chromeos/fileapi/memory_file_util_unittest.cc
@@ -0,0 +1,825 @@
+// Copyright (c) 2011 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/bind.h"
+#include "base/message_loop.h"
+#include "base/platform_file.h"
+#include "base/time.h"
+#include "testing/gtest/include/gtest/gtest.h"
+#include "webkit/chromeos/fileapi/memory_file_util.h"
+
+namespace {
+const FilePath::CharType kRootPath[] = "/mnt/memory";
+const char kTestString[] = "A test string. A test string.";
+const char kTestStringLength = arraysize(kTestString) - 1;
+}  // namespace
+
+namespace fileapi {
+
+// This test is actually testing MemoryFileUtil — an async in-memory file
+// system, based on FileUtilAsync.
+class MemoryFileUtilTest : public testing::Test {
+ public:
+  MemoryFileUtilTest() {
+  }
+
+  void SetUp() {
+    file_util_.reset(new MemoryFileUtil(FilePath(kRootPath)));
+  }
+
+  MemoryFileUtil* file_util() {
+    return file_util_.get();
+  }
+
+  enum CallbackType {
+    CALLBACK_TYPE_ERROR,
+    CALLBACK_TYPE_STATUS,
+    CALLBACK_TYPE_GET_FILE_INFO,
+    CALLBACK_TYPE_OPEN,
+    CALLBACK_TYPE_READ_WRITE,
+    CALLBACK_TYPE_READ_DIRECTORY
+  };
+
+  struct CallbackStatus {
+    CallbackType type;
+    base::PlatformFileError result;
+    base::PlatformFileInfo file_info;
+    // This object should be deleted in the test code.
+    AsyncFileStream* file_stream;
+    int64 length;
+
+    // Following 4 fields only for ReadDirectory.
+    FileUtilAsync::FileList entries;
+    bool completed;
+    bool called_after_completed;
+    int called;
+  };
+
+  FileUtilAsync::StatusCallback GetStatusCallback(int request_id) {
+    max_request_id_ = std::max(request_id, max_request_id_);
+    return base::Bind(&MemoryFileUtilTest::StatusCallbackImpl,
+                      base::Unretained(this),
+                      request_id);
+  }
+
+  FileUtilAsync::GetFileInfoCallback GetGetFileInfoCallback(
+      int request_id) {
+    max_request_id_ = std::max(request_id, max_request_id_);
+    return base::Bind(&MemoryFileUtilTest::GetFileInfoCallback,
+                      base::Unretained(this),
+                      request_id);
+  }
+
+  FileUtilAsync::OpenCallback GetOpenCallback(int request_id) {
+    max_request_id_ = std::max(request_id, max_request_id_);
+    return base::Bind(&MemoryFileUtilTest::OpenCallback,
+                      base::Unretained(this),
+                      request_id);
+  }
+
+  AsyncFileStream::ReadWriteCallback GetReadWriteCallback(int request_id) {
+    max_request_id_ = std::max(request_id, max_request_id_);
+    return base::Bind(&MemoryFileUtilTest::ReadWriteCallbackImpl,
+                      base::Unretained(this),
+                      request_id);
+  }
+
+  FileUtilAsync::ReadDirectoryCallback GetReadDirectoryCallback(
+      int request_id) {
+    if (request_id > max_request_id_) {
+      max_request_id_ = request_id;
+    }
+    return base::Bind(&MemoryFileUtilTest::ReadDirectoryCallback,
+                      base::Unretained(this),
+                      request_id);
+  }
+
+  int CreateEmptyFile(const FilePath& file_path) {
+    int request_id = GetNextRequestId();
+    file_util_->Create(file_path, GetStatusCallback(request_id));
+    return request_id;
+  }
+
+  int CreateNonEmptyFile(const FilePath& file_path,
+                         const char* data,
+                         int length) {
+    int request_id = GetNextRequestId();
+    file_util_->Open(
+        file_path,
+        base::PLATFORM_FILE_CREATE | base::PLATFORM_FILE_WRITE,
+        base::Bind(&MemoryFileUtilTest::WriteToOpenedFile,
+                   base::Unretained(this),
+                   request_id, data, length));
+    return request_id;
+  }
+
+  CallbackType GetStatusType(int request_id) {
+    if (status_map_.find(request_id) == status_map_.end())
+      return CALLBACK_TYPE_ERROR;
+    return status_map_[request_id].type;
+  }
+
+  // Return the operation status.
+  CallbackStatus& GetStatus(int request_id) {
+    return status_map_[request_id];
+  }
+
+  int StatusQueueSize() {
+    return status_map_.size();
+  }
+
+  int GetNextRequestId() {
+    return ++max_request_id_;
+  }
+
+  void set_read_directory_buffer_size(int size) {
+    file_util_->set_read_directory_buffer_size(size);
+  }
+
+ private:
+  void StatusCallbackImpl(int request_id, PlatformFileError result) {
+    CallbackStatus status;
+    status.type = CALLBACK_TYPE_STATUS;
+    status.result = result;
+    status_map_[request_id] = status;
+  }
+
+  void GetFileInfoCallback(int request_id,
+                           PlatformFileError result,
+                           const base::PlatformFileInfo& file_info) {
+    CallbackStatus status;
+    status.type = CALLBACK_TYPE_GET_FILE_INFO;
+    status.result = result;
+    status.file_info = file_info;
+    status_map_[request_id] = status;
+  }
+
+  void OpenCallback(int request_id,
+                    PlatformFileError result,
+                    AsyncFileStream* file_stream) {
+    CallbackStatus status;
+    status.type = CALLBACK_TYPE_OPEN;
+    status.result = result;
+    status.file_stream = file_stream;
+    status_map_[request_id] = status;
+  }
+
+  void ReadWriteCallbackImpl(int request_id,
+                             PlatformFileError result,
+                             int64 length) {
+    CallbackStatus status;
+    status.type = CALLBACK_TYPE_READ_WRITE;
+    status.result = result;
+    status.length = length;
+    status_map_[request_id] = status;
+  }
+
+  void ReadDirectoryCallback(int request_id,
+                             PlatformFileError result,
+                             const FileUtilAsync::FileList& entries,
+                             bool completed) {
+    if (status_map_.find(request_id) == status_map_.end()) {
+      CallbackStatus status;
+      status.type = CALLBACK_TYPE_READ_DIRECTORY;
+      status.called_after_completed = false;
+      status.result = result;
+      status.completed = completed;
+      status.called = 1;
+      status.entries = entries;
+      status_map_[request_id] = status;
+    } else {
+      CallbackStatus& status = status_map_[request_id];
+      if (status.completed)
+        status.called_after_completed = true;
+      status.result = result;
+      status.completed = completed;
+      ++status.called;
+      status.entries.insert(status.entries.begin(), entries.begin(),
+                            entries.end());
+    }
+  }
+
+  void WriteToOpenedFile(int request_id,
+                         const char* data,
+                         int length,
+                         PlatformFileError result,
+                         AsyncFileStream* stream) {
+    CallbackStatus status;
+    status.type = CALLBACK_TYPE_OPEN;
+    status.result = result;
+    status_map_[request_id] = status;
+    stream->Write(data, length, GetReadWriteCallback(GetNextRequestId()));
+  }
+
+  scoped_ptr<MemoryFileUtil> file_util_;
+  std::map<int, CallbackStatus> status_map_;
+  int max_request_id_;
+
+  DISALLOW_COPY_AND_ASSIGN(MemoryFileUtilTest);
+};
+
+TEST_F(MemoryFileUtilTest, TestCreateGetFileInfo) {
+  const int request_id1 = GetNextRequestId();
+  file_util()->GetFileInfo(FilePath("/mnt/memory/test.txt"),
+                           GetGetFileInfoCallback(request_id1));
+
+  // In case the file system is truely asynchronous, RunAllPending is not
+  // enough to wait for answer. In that case the thread should be blocked
+  // until the callback is called (ex. use Run() instead here, and call
+  // Quit() from callback).
+  MessageLoop::current()->RunAllPending();
+
+  ASSERT_EQ(CALLBACK_TYPE_GET_FILE_INFO, GetStatusType(request_id1));
+  CallbackStatus status = GetStatus(request_id1);
+  ASSERT_EQ(base::PLATFORM_FILE_ERROR_NOT_FOUND, status.result);
+
+  base::Time start_create = base::Time::Now();
+
+  const int request_id2 = GetNextRequestId();
+  file_util()->Create(FilePath("/mnt/memory/test.txt"),
+                      GetStatusCallback(request_id2));
+  MessageLoop::current()->RunAllPending();
+  ASSERT_EQ(CALLBACK_TYPE_STATUS, GetStatusType(request_id2));
+  status = GetStatus(request_id2);
+  ASSERT_EQ(base::PLATFORM_FILE_OK, status.result);
+
+  file_util()->GetFileInfo(FilePath("/mnt/memory/test.txt"),
+                           GetGetFileInfoCallback(3));
+  MessageLoop::current()->RunAllPending();
+
+  base::Time end_create = base::Time::Now();
+
+  ASSERT_EQ(CALLBACK_TYPE_GET_FILE_INFO, GetStatusType(3));
+  status = GetStatus(3);
+  ASSERT_EQ(base::PLATFORM_FILE_OK, status.result);
+  ASSERT_EQ(0, status.file_info.size);
+  ASSERT_FALSE(status.file_info.is_directory);
+  ASSERT_FALSE(status.file_info.is_symbolic_link);
+  ASSERT_GE(status.file_info.last_modified, start_create);
+  ASSERT_LE(status.file_info.last_modified, end_create);
+  ASSERT_GE(status.file_info.creation_time, start_create);
+  ASSERT_LE(status.file_info.creation_time, end_create);
+}
+
+TEST_F(MemoryFileUtilTest, TestReadWrite) {
+  // Check that the file does not exist.
+
+  const int request_id1 = GetNextRequestId();
+  file_util()->GetFileInfo(FilePath("/mnt/memory/test1.txt"),
+                           GetGetFileInfoCallback(request_id1));
+
+  MessageLoop::current()->RunAllPending();
+
+  ASSERT_EQ(CALLBACK_TYPE_GET_FILE_INFO, GetStatusType(request_id1));
+  CallbackStatus status = GetStatus(request_id1);
+  ASSERT_EQ(base::PLATFORM_FILE_ERROR_NOT_FOUND, status.result);
+
+  // Create & open file for writing.
+
+  base::Time start_create = base::Time::Now();
+  const int request_id2 = GetNextRequestId();
+  file_util()->Open(FilePath("/mnt/memory/test1.txt"),
+                    base::PLATFORM_FILE_CREATE_ALWAYS |
+                    base::PLATFORM_FILE_WRITE,
+                    GetOpenCallback(request_id2));
+  MessageLoop::current()->RunAllPending();
+
+  base::Time end_create = base::Time::Now();
+
+  ASSERT_EQ(CALLBACK_TYPE_OPEN, GetStatusType(request_id2));
+  status = GetStatus(request_id2);
+  ASSERT_EQ(base::PLATFORM_FILE_OK, status.result);
+
+  AsyncFileStream* write_file_stream = status.file_stream;
+
+  // Check that file was created and has 0 size.
+
+  const int request_id3 = GetNextRequestId();
+  file_util()->GetFileInfo(FilePath("/mnt/memory/test1.txt"),
+                           GetGetFileInfoCallback(request_id3));
+  MessageLoop::current()->RunAllPending();
+
+  ASSERT_EQ(CALLBACK_TYPE_GET_FILE_INFO, GetStatusType(request_id3));
+  status = GetStatus(request_id3);
+  ASSERT_EQ(base::PLATFORM_FILE_OK, status.result);
+  ASSERT_EQ(0, status.file_info.size);
+  ASSERT_FALSE(status.file_info.is_directory);
+  ASSERT_FALSE(status.file_info.is_symbolic_link);
+  ASSERT_GE(status.file_info.last_modified, start_create);
+  ASSERT_LE(status.file_info.last_modified, end_create);
+
+  // Write 10 bytes to file.
+
+  const int request_id4 = GetNextRequestId();
+  base::Time start_write = base::Time::Now();
+  write_file_stream->Write(kTestString, 10,
+                           GetReadWriteCallback(request_id4));
+  MessageLoop::current()->RunAllPending();
+  base::Time end_write = base::Time::Now();
+
+  ASSERT_EQ(CALLBACK_TYPE_READ_WRITE, GetStatusType(request_id4));
+  status = GetStatus(request_id4);
+  ASSERT_EQ(base::PLATFORM_FILE_OK, status.result);
+  ASSERT_EQ(10, status.length);
+
+  // Check that the file has now size 10 and correct modification time.
+
+  const int request_id5 = GetNextRequestId();
+  file_util()->GetFileInfo(FilePath("/mnt/memory/test1.txt"),
+                           GetGetFileInfoCallback(request_id5));
+  MessageLoop::current()->RunAllPending();
+
+  ASSERT_EQ(CALLBACK_TYPE_GET_FILE_INFO, GetStatusType(request_id5));
+  status = GetStatus(request_id5);
+  ASSERT_EQ(base::PLATFORM_FILE_OK, status.result);
+  ASSERT_EQ(10, status.file_info.size);
+  ASSERT_GE(status.file_info.last_modified, start_write);
+  ASSERT_LE(status.file_info.last_modified, end_write);
+
+  // Write the rest of the string to file.
+
+  const int request_id6 = GetNextRequestId();
+  start_write = base::Time::Now();
+  write_file_stream->Write(kTestString + 10,
+                           kTestStringLength - 10,
+                           GetReadWriteCallback(request_id6));
+  MessageLoop::current()->RunAllPending();
+  end_write = base::Time::Now();
+
+  ASSERT_EQ(CALLBACK_TYPE_READ_WRITE, GetStatusType(request_id6));
+  status = GetStatus(request_id6);
+  ASSERT_EQ(base::PLATFORM_FILE_OK, status.result);
+  ASSERT_EQ(static_cast<int64>(kTestStringLength) - 10, status.length);
+
+  // Check the file size & modification time.
+
+  const int request_id7 = GetNextRequestId();
+  file_util()->GetFileInfo(FilePath("/mnt/memory/test1.txt"),
+                           GetGetFileInfoCallback(request_id7));
+  MessageLoop::current()->RunAllPending();
+
+  ASSERT_EQ(CALLBACK_TYPE_GET_FILE_INFO, GetStatusType(request_id7));
+  status = GetStatus(request_id7);
+  ASSERT_EQ(base::PLATFORM_FILE_OK, status.result);
+  ASSERT_EQ(static_cast<int64>(kTestStringLength), status.file_info.size);
+  ASSERT_GE(status.file_info.last_modified, start_write);
+  ASSERT_LE(status.file_info.last_modified, end_write);
+
+  // Open file for reading.
+
+  const int request_id8 = GetNextRequestId();
+  file_util()->Open(FilePath("/mnt/memory/test1.txt"),
+                    base::PLATFORM_FILE_OPEN | base::PLATFORM_FILE_READ,
+                    GetOpenCallback(request_id8));
+  MessageLoop::current()->RunAllPending();
+
+  ASSERT_EQ(CALLBACK_TYPE_OPEN, GetStatusType(request_id8));
+  status = GetStatus(request_id8);
+  ASSERT_EQ(base::PLATFORM_FILE_OK, status.result);
+  ASSERT_EQ(base::PLATFORM_FILE_OK, status.result);
+
+  scoped_ptr<AsyncFileStream> read_file_stream(status.file_stream);
+
+  // Read the whole file
+  char buffer[1024];
+  const int request_id9 = GetNextRequestId();
+  read_file_stream->Read(buffer, 1023, GetReadWriteCallback(request_id9));
+  MessageLoop::current()->RunAllPending();
+
+  ASSERT_EQ(CALLBACK_TYPE_READ_WRITE, GetStatusType(request_id9));
+  status = GetStatus(request_id9);
+  ASSERT_EQ(base::PLATFORM_FILE_OK, status.result);
+  ASSERT_EQ(static_cast<int64>(kTestStringLength), status.length);
+
+  buffer[status.length] = '\0';
+  std::string result_string(buffer);
+  ASSERT_EQ(kTestString, result_string);
+
+  // Check that size & modification time have not changed.
+
+  const int request_id10 = GetNextRequestId();
+  file_util()->GetFileInfo(FilePath("/mnt/memory/test1.txt"),
+                           GetGetFileInfoCallback(request_id10));
+  MessageLoop::current()->RunAllPending();
+
+  ASSERT_EQ(CALLBACK_TYPE_GET_FILE_INFO, GetStatusType(request_id10));
+  status = GetStatus(request_id10);
+  ASSERT_EQ(base::PLATFORM_FILE_OK, status.result);
+  ASSERT_EQ(static_cast<int64>(kTestStringLength), status.file_info.size);
+  ASSERT_GE(status.file_info.last_modified, start_write);
+  ASSERT_LE(status.file_info.last_modified, end_write);
+
+  // Open once more for writing.
+
+  const int request_id11 = GetNextRequestId();
+  file_util()->Open(FilePath("/mnt/memory/test1.txt"),
+                    base::PLATFORM_FILE_OPEN | base::PLATFORM_FILE_WRITE,
+                    GetOpenCallback(request_id11));
+  MessageLoop::current()->RunAllPending();
+
+  ASSERT_EQ(CALLBACK_TYPE_OPEN, GetStatusType(request_id11));
+  status = GetStatus(request_id11);
+  ASSERT_EQ(base::PLATFORM_FILE_OK, status.result);
+
+  scoped_ptr<AsyncFileStream> write_file_stream2(status.file_stream);
+
+  // Check that the size has not changed.
+
+  const int request_id12 = GetNextRequestId();
+  file_util()->GetFileInfo(FilePath("/mnt/memory/test1.txt"),
+                           GetGetFileInfoCallback(request_id12));
+  MessageLoop::current()->RunAllPending();
+
+  ASSERT_EQ(CALLBACK_TYPE_GET_FILE_INFO, GetStatusType(request_id12));
+  status = GetStatus(request_id12);
+  ASSERT_EQ(base::PLATFORM_FILE_OK, status.result);
+  ASSERT_EQ(static_cast<int64>(kTestStringLength), status.file_info.size);
+
+  // Seek beyond the end of file. Should return error.
+
+  const int request_id13 = GetNextRequestId();
+  write_file_stream2->Seek(1000, GetStatusCallback(request_id13));
+  MessageLoop::current()->RunAllPending();
+  ASSERT_EQ(CALLBACK_TYPE_STATUS, GetStatusType(request_id13));
+  status = GetStatus(request_id13);
+  ASSERT_EQ(base::PLATFORM_FILE_ERROR_INVALID_OPERATION, status.result);
+
+  // Try to write to read-only stream.
+
+  const int request_id14 = GetNextRequestId();
+  read_file_stream->Write(kTestString,
+                          kTestStringLength,
+                          GetReadWriteCallback(request_id14));
+  MessageLoop::current()->RunAllPending();
+  status = GetStatus(request_id14);
+  ASSERT_EQ(base::PLATFORM_FILE_ERROR_INVALID_OPERATION, status.result);
+
+  // Write data overlapping with already written.
+
+
+  const int request_id15 = GetNextRequestId();
+  write_file_stream2->Seek(10, GetStatusCallback(request_id15));
+  MessageLoop::current()->RunAllPending();
+  ASSERT_EQ(base::PLATFORM_FILE_OK, GetStatus(request_id15).result);
+
+  const int request_id16 = GetNextRequestId();
+  write_file_stream2->Write(kTestString,
+                            kTestStringLength,
+                            GetReadWriteCallback(request_id16));
+  MessageLoop::current()->RunAllPending();
+  status = GetStatus(request_id16);
+  ASSERT_EQ(base::PLATFORM_FILE_OK, status.result);
+  ASSERT_EQ(static_cast<int64>(kTestStringLength), status.length);
+
+  // Check size.
+
+  const int request_id17 = GetNextRequestId();
+  file_util()->GetFileInfo(FilePath("/mnt/memory/test1.txt"),
+                           GetGetFileInfoCallback(request_id17));
+  MessageLoop::current()->RunAllPending();
+  status = GetStatus(request_id17);
+  ASSERT_EQ(base::PLATFORM_FILE_OK, status.result);
+  ASSERT_EQ(static_cast<int64>(kTestStringLength) + 10,
+            status.file_info.size);
+
+  // Read from 10th byte.
+  const int request_id18 = GetNextRequestId();
+  read_file_stream->Seek(10, GetStatusCallback(request_id18));
+  MessageLoop::current()->RunAllPending();
+  ASSERT_EQ(base::PLATFORM_FILE_OK, GetStatus(request_id18).result);
+
+  const int request_id19 = GetNextRequestId();
+  read_file_stream->Read(buffer, 1023, GetReadWriteCallback(request_id19));
+  MessageLoop::current()->RunAllPending();
+  status = GetStatus(request_id19);
+  ASSERT_EQ(base::PLATFORM_FILE_OK, status.result);
+  ASSERT_EQ(static_cast<int64>(kTestStringLength), status.length);
+  buffer[status.length] = '\0';
+  std::string result_string2(buffer);
+  ASSERT_EQ(kTestString, result_string2);
+}
+
+// The directory structure we'll be testing on:
+// path                    size
+//
+// /mnt/memory/a           0
+// /mnt/memory/b/
+// /mnt/memory/b/c         kTestStringLength
+// /mnt/memory/b/d/
+// /mnt/memory/b/e         0
+// /mnt/memory/b/f         kTestStringLength
+// /mnt/memory/b/g/
+// /mnt/memory/b/g/h       0
+// /mnt/memory/b/i         kTestStringLength
+// /mnt/memory/c/
+// /mnt/memory/longer_file_name.txt kTestStringLength
+TEST_F(MemoryFileUtilTest, TestDirectoryOperations) {
+  // Check the directory is empty.
+  const int request_id0 = GetNextRequestId();
+  file_util()->ReadDirectory(FilePath("/mnt/memory/"),
+                             GetReadDirectoryCallback(request_id0));
+
+  MessageLoop::current()->RunAllPending();
+
+  ASSERT_EQ(CALLBACK_TYPE_READ_DIRECTORY, GetStatusType(request_id0));
+  CallbackStatus& status = GetStatus(request_id0);
+  ASSERT_TRUE(status.completed);
+  ASSERT_FALSE(status.called_after_completed);
+  ASSERT_EQ(1, status.called);
+  ASSERT_EQ(0u, status.entries.size());
+
+  // Create /mnt/memory/a, /mnt/memory/b/, /mnt/memory/longer_file_name.txt,
+  // /mnt/memory/c/ asyncronously (i.e. we do not wait for each operation to
+  // complete before starting the next one.
+
+  base::Time start_create = base::Time::Now();
+  CreateEmptyFile(FilePath("/mnt/memory/a"));
+
+  int request_id1 = GetNextRequestId();
+  file_util()->CreateDirectory(FilePath("/mnt/memory/b"),
+                               GetStatusCallback(request_id1));
+
+  CreateNonEmptyFile(FilePath("/mnt/memory/longer_file_name.txt"),
+                     kTestString,
+                     kTestStringLength);
+
+  int request_id2 = GetNextRequestId();
+  file_util()->CreateDirectory(FilePath("/mnt/memory/c"),
+                               GetStatusCallback(request_id2));
+
+  MessageLoop::current()->RunAllPending();
+  base::Time end_create = base::Time::Now();
+
+  ASSERT_EQ(base::PLATFORM_FILE_OK, GetStatus(request_id1).result);
+  ASSERT_EQ(base::PLATFORM_FILE_OK, GetStatus(request_id2).result);
+
+  // ReadDirectory /mnt/memory, /mnt/memory/a (not a dir), /mnt/memory/b/,
+  // /mnt/memory/d (not found)
+
+  set_read_directory_buffer_size(5);  // Should complete in one go.
+
+  request_id1 = GetNextRequestId();
+  file_util()->ReadDirectory(FilePath("/mnt/memory"),
+                             GetReadDirectoryCallback(request_id1));
+  request_id2 = GetNextRequestId();
+  file_util()->ReadDirectory(FilePath("/mnt/memory/a"),
+                             GetReadDirectoryCallback(request_id2));
+  const int request_id3 = GetNextRequestId();
+  file_util()->ReadDirectory(FilePath("/mnt/memory/b/"),
+                             GetReadDirectoryCallback(request_id3));
+  const int request_id4 = GetNextRequestId();
+  file_util()->ReadDirectory(FilePath("/mnt/memory/d/"),
+                             GetReadDirectoryCallback(request_id4));
+
+  MessageLoop::current()->RunAllPending();
+
+  ASSERT_EQ(base::PLATFORM_FILE_OK, GetStatus(request_id1).result);
+  status = GetStatus(request_id1);
+  ASSERT_TRUE(status.completed);
+  ASSERT_FALSE(status.called_after_completed);
+  ASSERT_EQ(1, status.called);  // Because the number of entries < 5.
+  ASSERT_EQ(4u, status.entries.size());
+
+  std::set<FilePath::StringType> seen;
+
+  for (FileUtilAsync::FileList::const_iterator it = status.entries.begin();
+       it != status.entries.end();
+       ++it) {
+    ASSERT_LE(start_create, it->last_modified_time);
+    ASSERT_GE(end_create, it->last_modified_time);
+
+    ASSERT_EQ(seen.end(), seen.find(it->name));
+    seen.insert(it->name);
+
+    if (it->name == "a") {
+      ASSERT_FALSE(it->is_directory);
+      ASSERT_EQ(0, it->size);
+    } else if (it->name == "b") {
+      ASSERT_TRUE(it->is_directory);
+    } else if (it->name == "c") {
+      ASSERT_TRUE(it->is_directory);
+    } else if (it->name == "longer_file_name.txt") {
+      ASSERT_FALSE(it->is_directory);
+      ASSERT_EQ(static_cast<int64>(kTestStringLength), it->size);
+    } else {
+      LOG(ERROR) << "Unexpected file: " << it->name;
+      ASSERT_TRUE(false);
+    }
+  }
+
+  ASSERT_EQ(base::PLATFORM_FILE_ERROR_NOT_A_DIRECTORY,
+            GetStatus(request_id2).result);
+
+  status = GetStatus(request_id3);
+  ASSERT_TRUE(status.completed);
+  ASSERT_FALSE(status.called_after_completed);
+  ASSERT_EQ(1, status.called);
+  ASSERT_EQ(0u, status.entries.size());
+
+  ASSERT_EQ(base::PLATFORM_FILE_ERROR_NOT_FOUND, GetStatus(request_id4).result);
+
+  // Create files & dirs inside b/:
+  // /mnt/memory/b/c         kTestStringLength
+  // /mnt/memory/b/d/
+  // /mnt/memory/b/e         0
+  // /mnt/memory/b/f         kTestStringLength
+  // /mnt/memory/b/g/
+  // /mnt/memory/b/i         kTestStringLength
+  //
+  // /mnt/memory/b/g/h       0
+
+  start_create = base::Time::Now();
+  CreateNonEmptyFile(FilePath("/mnt/memory/b/c"),
+                     kTestString,
+                     kTestStringLength);
+  request_id1 = GetNextRequestId();
+  file_util()->CreateDirectory(FilePath("/mnt/memory/b/d"),
+                               GetStatusCallback(request_id1));
+  CreateEmptyFile(FilePath("/mnt/memory/b/e"));
+  CreateNonEmptyFile(FilePath("/mnt/memory/b/f"),
+                     kTestString,
+                     kTestStringLength);
+  request_id2 = GetNextRequestId();
+  file_util()->CreateDirectory(FilePath("/mnt/memory/b/g"),
+                               GetStatusCallback(request_id1));
+  CreateNonEmptyFile(FilePath("/mnt/memory/b/i"),
+                     kTestString,
+                     kTestStringLength);
+
+  MessageLoop::current()->RunAllPending();
+
+  CreateEmptyFile(FilePath("/mnt/memory/b/g/h"));
+
+  MessageLoop::current()->RunAllPending();
+  end_create = base::Time::Now();
+
+  // Read /mnt/memory and check that the number of entries is unchanged.
+
+  request_id1 = GetNextRequestId();
+  file_util()->ReadDirectory(FilePath("/mnt/memory"),
+                             GetReadDirectoryCallback(request_id1));
+
+  MessageLoop::current()->RunAllPending();
+
+  ASSERT_EQ(base::PLATFORM_FILE_OK, GetStatus(request_id1).result);
+  status = GetStatus(request_id1);
+  ASSERT_TRUE(status.completed);
+  ASSERT_FALSE(status.called_after_completed);
+  ASSERT_EQ(1, status.called);  // Because the number of entries < 5.
+  ASSERT_EQ(4u, status.entries.size());
+
+  // Read /mnt/memory/b
+
+  request_id1 = GetNextRequestId();
+  file_util()->ReadDirectory(FilePath("/mnt/memory/b"),
+                             GetReadDirectoryCallback(request_id1));
+
+  MessageLoop::current()->RunAllPending();
+
+  ASSERT_EQ(base::PLATFORM_FILE_OK, GetStatus(request_id1).result);
+  status = GetStatus(request_id1);
+  ASSERT_TRUE(status.completed);
+  ASSERT_FALSE(status.called_after_completed);
+  ASSERT_EQ(2, status.called);  // Because the number of entries > 5.
+  ASSERT_EQ(6u, status.entries.size());
+
+  seen.clear();
+
+  for (FileUtilAsync::FileList::const_iterator it = status.entries.begin();
+       it != status.entries.end();
+       ++it) {
+    ASSERT_LE(start_create, it->last_modified_time);
+    ASSERT_GE(end_create, it->last_modified_time);
+
+    ASSERT_EQ(seen.end(), seen.find(it->name));
+    seen.insert(it->name);
+
+    // /mnt/memory/b/c         kTestStringLength
+    // /mnt/memory/b/d/
+    // /mnt/memory/b/e         0
+    // /mnt/memory/b/f         kTestStringLength
+    // /mnt/memory/b/g/
+    // /mnt/memory/b/i         kTestStringLength
+
+    if (it->name == "c") {
+      ASSERT_FALSE(it->is_directory);
+      ASSERT_EQ(static_cast<int64>(kTestStringLength), it->size);
+    } else if (it->name == "d") {
+      ASSERT_TRUE(it->is_directory);
+    } else if (it->name == "e") {
+      ASSERT_FALSE(it->is_directory);
+      ASSERT_EQ(0, it->size);
+    } else if (it->name == "f") {
+      ASSERT_FALSE(it->is_directory);
+      ASSERT_EQ(static_cast<int64>(kTestStringLength), it->size);
+    } else if (it->name == "g") {
+      ASSERT_TRUE(it->is_directory);
+    } else if (it->name == "i") {
+      ASSERT_FALSE(it->is_directory);
+      ASSERT_EQ(static_cast<int64>(kTestStringLength), it->size);
+    } else {
+      LOG(ERROR) << "Unexpected file: " << it->name;
+      ASSERT_TRUE(false);
+    }
+  }
+
+  // Remove single file: /mnt/memory/b/f
+
+  request_id1 = GetNextRequestId();
+  file_util()->Remove(FilePath("/mnt/memory/b/f"), false /* recursive */,
+                      GetStatusCallback(request_id1));
+  MessageLoop::current()->RunAllPending();
+  ASSERT_EQ(base::PLATFORM_FILE_OK, GetStatus(request_id1).result);
+
+  // Check the number of files in b/
+
+  request_id1 = GetNextRequestId();
+  file_util()->ReadDirectory(FilePath("/mnt/memory/b"),
+                             GetReadDirectoryCallback(request_id1));
+
+  MessageLoop::current()->RunAllPending();
+
+  ASSERT_EQ(base::PLATFORM_FILE_OK, GetStatus(request_id1).result);
+  status = GetStatus(request_id1);
+  ASSERT_TRUE(status.completed);
+  ASSERT_FALSE(status.called_after_completed);
+  ASSERT_EQ(5u, status.entries.size());
+
+  // Try remove /mnt/memory/b non-recursively (error)
+
+  request_id1 = GetNextRequestId();
+  file_util()->Remove(FilePath("/mnt/memory/b"), false /* recursive */,
+                      GetStatusCallback(request_id1));
+  MessageLoop::current()->RunAllPending();
+  ASSERT_EQ(base::PLATFORM_FILE_ERROR_NOT_A_FILE,
+            GetStatus(request_id1).result);
+
+  // Non-recursively remove empty directory.
+
+  request_id1 = GetNextRequestId();
+  file_util()->Remove(FilePath("/mnt/memory/b/d"), false /* recursive */,
+                      GetStatusCallback(request_id1));
+  MessageLoop::current()->RunAllPending();
+  ASSERT_EQ(base::PLATFORM_FILE_OK, GetStatus(request_id1).result);
+
+  request_id1 = GetNextRequestId();
+  file_util()->GetFileInfo(FilePath("/mnt/memory/b/d"),
+                           GetGetFileInfoCallback(request_id1));
+  MessageLoop::current()->RunAllPending();
+  ASSERT_EQ(base::PLATFORM_FILE_ERROR_NOT_FOUND, GetStatus(request_id1).result);
+
+  // Remove /mnt/memory/b recursively.
+
+  request_id1 = GetNextRequestId();
+  file_util()->Remove(FilePath("/mnt/memory/b"), true /* recursive */,
+                      GetStatusCallback(request_id1));
+  MessageLoop::current()->RunAllPending();
+  ASSERT_EQ(base::PLATFORM_FILE_OK, GetStatus(request_id1).result);
+
+  // ReadDirectory /mnt/memory/b -> not found
+
+  request_id1 = GetNextRequestId();
+  file_util()->ReadDirectory(FilePath("/mnt/memory/b"),
+                             GetReadDirectoryCallback(request_id1));
+  MessageLoop::current()->RunAllPending();
+  ASSERT_EQ(base::PLATFORM_FILE_ERROR_NOT_FOUND, GetStatus(request_id1).result);
+
+  // ReadDirectory /mnt/memory
+
+  request_id1 = GetNextRequestId();
+  file_util()->ReadDirectory(FilePath("/mnt/memory"),
+                             GetReadDirectoryCallback(request_id1));
+
+  MessageLoop::current()->RunAllPending();
+
+  ASSERT_EQ(base::PLATFORM_FILE_OK, GetStatus(request_id1).result);
+  status = GetStatus(request_id1);
+  ASSERT_TRUE(status.completed);
+  ASSERT_FALSE(status.called_after_completed);
+  ASSERT_EQ(3u, status.entries.size());
+
+  seen.clear();
+
+  for (FileUtilAsync::FileList::const_iterator it = status.entries.begin();
+       it != status.entries.end();
+       ++it) {
+    ASSERT_EQ(seen.end(), seen.find(it->name));
+    seen.insert(it->name);
+
+    if (it->name == "a") {
+      ASSERT_FALSE(it->is_directory);
+      ASSERT_EQ(0, it->size);
+    } else if (it->name == "c") {
+      ASSERT_TRUE(it->is_directory);
+    } else if (it->name == "longer_file_name.txt") {
+      ASSERT_FALSE(it->is_directory);
+      ASSERT_EQ(static_cast<int64>(kTestStringLength), it->size);
+    } else {
+      LOG(ERROR) << "Unexpected file: " << it->name;
+      ASSERT_TRUE(false);
+    }
+  }
+}
+
+}  // namespace fileapi