Add 1st cut of FileSystemUsageTracker that tracks the usage changes in FileSystem API.

webkit/fileapi/file_system_usage_tracker.cc

Index: webkit/fileapi/file_system_usage_tracker.cc
diff --git a/webkit/fileapi/file_system_usage_tracker.cc b/webkit/fileapi/file_system_usage_tracker.cc
new file mode 100644
index 0000000000000000000000000000000000000000..9cb3e4240fbc85deb887c5677922c48a49c83fa6
--- /dev/null
+++ b/webkit/fileapi/file_system_usage_tracker.cc
@@ -0,0 +1,156 @@
+// 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 "webkit/fileapi/file_system_usage_tracker.h"
+
+#include "base/file_path.h"
+#include "base/file_util.h"
+#include "base/logging.h"
+#include "base/message_loop_proxy.h"
+#include "base/scoped_ptr.h"
+#include "base/task.h"
+#include "googleurl/src/gurl.h"
+#include "webkit/fileapi/file_system_path_manager.h"
+
+namespace fileapi {
+
+class FileSystemUsageTracker::GetUsageTask
+    : public base::RefCountedThreadSafe<GetUsageTask> {
+ public:
+  GetUsageTask(
+      FileSystemUsageTracker* tracker,
+      scoped_refptr<base::MessageLoopProxy> file_message_loop,
+      std::string fs_name,
+      const FilePath& origin_base_path)
+      : tracker_(tracker),
+        file_message_loop_(file_message_loop),
+        origin_message_loop_(
+            base::MessageLoopProxy::CreateForCurrentThread()),
+        fs_name_(fs_name),
+        fs_usage_(0),
+        origin_base_path_(origin_base_path) {
+  }
+
+  virtual ~GetUsageTask() {}
+
+  void Start() {
+    if (tracker_)
+      tracker_->RegisterUsageTask(this);
+    file_message_loop_->PostTask(
+        FROM_HERE, NewRunnableMethod(this, &GetUsageTask::RunOnFileThread));
+  }
+
+  void RunOnFileThread() {
+    DCHECK(file_message_loop_->BelongsToCurrentThread());
+
+    // TODO(dmikurube): add the code that retrieves the origin usage here.
+
+    origin_message_loop_->PostTask(
+        FROM_HERE, NewRunnableMethod(this, &GetUsageTask::Completed));
+  }
+
+  void Cancel() {
+    DCHECK(origin_message_loop_->BelongsToCurrentThread());
+    tracker_ = NULL;
+  }
+
+ private:
+  void Completed() {
+    DCHECK(origin_message_loop_->BelongsToCurrentThread());
+    if (tracker_) {
+      tracker_->UnregisterUsageTask(this);
+      tracker_->DidGetOriginUsage(fs_name_, fs_usage_);
+    }
+  }
+
+  FileSystemUsageTracker* tracker_;
+  scoped_refptr<base::MessageLoopProxy> file_message_loop_;
+  scoped_refptr<base::MessageLoopProxy> origin_message_loop_;
+  std::string fs_name_;
+  int64 fs_usage_;
+  FilePath origin_base_path_;
+};
+
+FileSystemUsageTracker::FileSystemUsageTracker(
+    scoped_refptr<base::MessageLoopProxy> file_message_loop,
+    const FilePath& profile_path,
+    bool is_incognito)
+    : file_message_loop_(file_message_loop),
+      base_path_(profile_path.Append(
+          FileSystemPathManager::kFileSystemDirectory)),
+      is_incognito_(is_incognito) {
+  DCHECK(file_message_loop);
+}
+
+FileSystemUsageTracker::~FileSystemUsageTracker() {
+  std::for_each(running_usage_tasks_.begin(),
+                running_usage_tasks_.end(),
+                std::mem_fun(&GetUsageTask::Cancel));
+}
+
+void FileSystemUsageTracker::GetOriginUsage(
+    const GURL& origin_url,
+    fileapi::FileSystemType type,
+    GetUsageCallback* callback_ptr) {
+  DCHECK(callback_ptr);
+  scoped_ptr<GetUsageCallback> callback(callback_ptr);
+
+  if (is_incognito_) {
+    // We don't support FileSystem in incognito mode yet.
+    callback->Run(0);
+    return;
+  }
+
+  std::string fs_name = FileSystemPathManager::GetFileSystemName(
+      origin_url, type);
+  if (pending_usage_callbacks_.find(fs_name) !=
+      pending_usage_callbacks_.end()) {
+    // Another get usage task is running.  Add the callback to
+    // the pending queue and return.
+    pending_usage_callbacks_[fs_name].push_back(callback.release());
+    return;
+  }
+
+  // Get the filesystem base path (i.e. "FileSystem/<origin>/<type>",
+  // without unique part).
+  FilePath origin_base_path =
+      FileSystemPathManager::GetFileSystemBaseDirectoryForOriginAndType(
+          base_path_, origin_url, type);
+  if (origin_base_path.empty()) {
+    // The request seems to be invalid.
+    callback->Run(0);
+    return;
+  }
+
+  pending_usage_callbacks_[fs_name].push_back(callback.release());
+  scoped_refptr<GetUsageTask> task(
+      new GetUsageTask(this, file_message_loop_, fs_name, origin_base_path));
+  task->Start();
+}
+
+void FileSystemUsageTracker::RegisterUsageTask(GetUsageTask* task) {
+  running_usage_tasks_.push_back(task);
+}
+
+void FileSystemUsageTracker::UnregisterUsageTask(GetUsageTask* task) {
+  DCHECK(running_usage_tasks_.front() == task);
+  running_usage_tasks_.pop_front();
+}
+
+void FileSystemUsageTracker::DidGetOriginUsage(
+    const std::string& fs_name, int64 usage) {
+  PendingUsageCallbackMap::iterator cb_list_iter =
+      pending_usage_callbacks_.find(fs_name);
+  DCHECK(cb_list_iter != pending_usage_callbacks_.end());
+  PendingCallbackList cb_list = cb_list_iter->second;
+  for (PendingCallbackList::iterator cb_iter = cb_list.begin();
+        cb_iter != cb_list.end();
+        ++cb_iter) {
+    scoped_ptr<GetUsageCallback> callback(*cb_iter);
+    callback->Run(usage);
+  }
+  pending_usage_callbacks_.erase(cb_list_iter);
+}
+
+}  // namespace fileapi