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/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