Drive: Removes unused cache files after the initial feed fetch.

chrome/browser/chromeos/gdata/stale_cache_files_remover.cc

+// Copyright (c) 2012 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 "chrome/browser/chromeos/gdata/stale_cache_files_remover.h"
+
+#include "base/bind.h"
+#include "base/message_loop.h"
+#include "chrome/browser/chromeos/gdata/drive_cache.h"
+#include "chrome/browser/chromeos/gdata/drive.pb.h"
+#include "chrome/browser/chromeos/gdata/drive_file_system.h"
+#include "content/public/browser/browser_thread.h"
+
+using content::BrowserThread;
+
+namespace gdata {
+
+namespace {
+
+// Emits the log when the remove failed.
+void EmitErrorLog(DriveFileError error,
+                  const std::string& resource_id,
+                  const std::string& md5) {
+  if (error != gdata::DRIVE_FILE_OK) {
+    LOG(WARNING) << "Failed to remove a stale cache file. resource_id:"
+                 << resource_id;
+  }
+}
+
+}  // namespace
+
+StaleCacheFilesRemover::StaleCacheFilesRemover(
+    DriveFileSystemInterface* file_system,
+    DriveCache* cache)
+    : cache_(cache),
+      file_system_(file_system),
+      ALLOW_THIS_IN_INITIALIZER_LIST(weak_ptr_factory_(this)) {
+  file_system_->AddObserver(this);
+}
+
+StaleCacheFilesRemover::~StaleCacheFilesRemover() {
+  file_system_->RemoveObserver(this);
+}
+
+void StaleCacheFilesRemover::OnInitialLoadFinished() {
+  DCHECK(BrowserThread::CurrentlyOn(BrowserThread::UI));
+
+  const FilePath root_path = FilePath(gdata::kDriveRootDirectory);
+  cache_->GetResourceIdsOfAllFilesOnUIThread(
+      base::Bind(&StaleCacheFilesRemover::OnGetResourceIdsOfAllFiles,
+                 weak_ptr_factory_.GetWeakPtr()));
+}
+
+void StaleCacheFilesRemover::OnGetResourceIdsOfAllFiles(
+    const std::vector<std::string>& resource_ids) {
+  DCHECK(BrowserThread::CurrentlyOn(BrowserThread::UI));
+
+  for (size_t i = 0; i < resource_ids.size(); ++i) {
+    const std::string& resource_id = resource_ids[i];
+    cache_->GetCacheEntryOnUIThread(
+        resource_id,
+        "",  // Don't check MD5.
+        base::Bind(
+            &StaleCacheFilesRemover::GetEntryInfoAndRemoveCacheIfNecessary,
+            weak_ptr_factory_.GetWeakPtr(),
+            resource_id));
+  }
+}
+
+void StaleCacheFilesRemover::GetEntryInfoAndRemoveCacheIfNecessary(
+    const std::string& resource_id,
+    bool success,
+    const gdata::DriveCacheEntry& cache_entry) {
+  DCHECK(BrowserThread::CurrentlyOn(BrowserThread::UI));
+
+  // Removes the cache if GetCacheEntryOnUIThread() failed.
+  if (!success) {
+    LOG(WARNING) << "GetCacheEntryOnUIThread() failed";
+    return;
+  }
+
+  file_system_->GetEntryInfoByResourceId(
+      resource_id,
+      base::Bind(&StaleCacheFilesRemover::RemoveCacheIfNecessary,
+                 weak_ptr_factory_.GetWeakPtr(),
+                 resource_id,
+                 cache_entry.md5()));
+}
+
+void StaleCacheFilesRemover::RemoveCacheIfNecessary(
+    const std::string& resource_id,
+    const std::string& cache_md5,
+    DriveFileError error,
+    const FilePath& gdata_file_path,
+    scoped_ptr<gdata::DriveEntryProto> entry_proto) {
+  DCHECK(BrowserThread::CurrentlyOn(BrowserThread::UI));
+
+  // The entry is not found in the file system.
+  if (error != gdata::DRIVE_FILE_OK) {
+    cache_->RemoveOnUIThread(resource_id, base::Bind(&EmitErrorLog));
+    return;
+  }
+
+  // The entry is found but the MD5 does not match.
+  DCHECK(entry_proto.get());
+  if (!entry_proto->has_file_specific_info() ||
+      cache_md5 != entry_proto->file_specific_info().file_md5()) {
+    cache_->RemoveOnUIThread(resource_id, base::Bind(&EmitErrorLog));
+    return;
+  }
+}
+
+}  // namespace gdata