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

webkit/chromeos/fileapi/memory_file_util.cc

+// 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 "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 owened by MemoryFileUtil.

[kinuko, 2011/12/14 11:19:13]

nit: s/owened/owned/

[satorux1, 2011/12/15 04:38:05]

Done.

+  MemoryFileUtilAsyncFileStream(
+      MemoryFileUtil::FileEntry* file_entry, int flags)

[kinuko, 2011/12/14 11:19:13]

style-nit:

MemoryFileUtilAsyncFileStream(MemoryFileUtil::FileEntry* file_entry,
                              int flags)

[satorux1, 2011/12/15 04:38:05]

Done.

+      : file_entry_(file_entry),
+        flags_(flags),
+        offset_(0) {
+  }
+
+  // AsyncFileStream override.
+  virtual void Read(char* buffer,
+                    int64 length,
+                    const ReadWriteCallback& callback) OVERRIDE {

[kinuko, 2011/12/14 11:19:13]

Just to make sure, we're dispatching callbacks synchronously in Stream while we
do asynchronously in AsyncFileUtil.  If we really want to test the async nature
of these interfaces we may want to run them in async tasks.

[Oleg Eterevsky, 2011/12/14 15:20:59]

I believe the callback must be called _after_ the call itself, so these
callback.Run's looks wrong to me. They should probably be replaced by
MessageLoop::current()->PostTask().

[satorux1, 2011/12/15 04:38:05]

Done.

+    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);
+  }
+
+  // AsyncFileStream override.
+  virtual void Write(const char* buffer,
+                     int64 length,
+                     const ReadWriteCallback& callback) OVERRIDE {
+    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);
+  }
+
+  // AsyncFileStream override.
+  virtual void Seek(int64 offset,
+                    const SeekCallback& callback) OVERRIDE {
+    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);
+  }
+
+ private:
+  // 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_;
+};
+
+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;
+}
+
+// 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,
+    RemoveMode mode,
+    const StatusCallback& callback) {
+  if (mode == RECURSIVE) {

[kinuko, 2011/12/14 11:19:13]

changing this into switch/case and having default with NOTREACHED check might be
better?

[satorux1, 2011/12/15 07:04:33]

Done.

+    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 that directory is empty.
+    FilePath path_with_separator = file_it->first.Append("/");

[kinuko, 2011/12/14 11:19:13]

Does this (path.Append("/")) work?
This looks strange to me since Append() is basically for appending path
components without worrying about separator itself.
(You'll need to call AppendASCII() or Append(FILE_PATH_LITERAL("/")) anyway on
Windows)

I think we should explicitly append FILE_PATH_LITERAL("/") to the path.value()
if we really want to do that manually.
(maybe we could make it an inline method and call it like
EnsureEndsWithSeparator())

[satorux1, 2011/12/15 07:04:33]

My bad, you are absolutely right. Besides, relying on '/' is not desirable as
Windows can use both / and \ as path separators. Removed code to rely on '/'.

+    FileIterator file_inside_dir = files_.lower_bound(path_with_separator);
+
+    if (file_it->first.IsParent(file_inside_dir->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;
+  }
+
+  // In the following code we rely on the fact that the paths in files_
+  // are ordered lexicographically. We iterate over files_ and delete
+  // the files from files_, then delete in one go all the files from
+  // file_by_name_.
+  FilePath file_path_with_separator = file_path.Append("/");
+  FileIterator it_first = files_.lower_bound(file_path_with_separator);
+  FileIterator it_last = it_first;
+
+  while (it_last != files_.end() && file_path.IsParent(it_last->first)) {
+    ++it_last;
+  }
+  files_.erase(it_first, it_last);
+
+  // The initial path is stored without a separator in the end, so it
+  // has not been removed in the above loop.
+  files_.erase(file_it);
+  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.Append("/");
+
+  bool completed = true;
+
+  // Here we iterate over all paths starting with the prefix dir_path + '/'.
+  // 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. (It could be done by using lower_bound instead
+  // of ++ in case we've met a subdirectory path.)
+  for (ConstFileIterator it = files_.lower_bound(from);
+       it != files_.end() && dir_path.IsParent(it->first);
+       ++it) {
+    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