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/gdata_cache.h"
+#include "chrome/browser/chromeos/gdata/gdata_file_system.h"
+#include "chrome/browser/chromeos/gdata/gdata.pb.h"
+#include "content/public/browser/browser_thread.h"
+
+using content::BrowserThread;
+
+namespace gdata {
+
+namespace {
+
+// Delay to scrub caches after the first feed fetch (in seconds).
+const int kDriveScrubDelayAfterFirstFeedFetch = 10;

[satorux1, 2012/08/10 23:47:40]

maybe just

kDelaySeconds = 10;

+
+void RemoveCacheIfNecessary(

[satorux1, 2012/08/10 23:47:40]

function comment is missing. please fix other places too.

+    const std::string& resource_id,
+    gdata::GDataCache* cache,
+    const std::string& cache_md5,
+    GDataFileError error,
+    const FilePath& gdata_file_path,
+    scoped_ptr<gdata::GDataEntryProto> file_proto) {
+  DCHECK(cache);
+  DCHECK(BrowserThread::CurrentlyOn(BrowserThread::UI));
+
+  // Removes the cache file if the givin cache status is invalid or unavailable.
+  if (error != gdata::GDATA_FILE_OK ||
+      !file_proto.get() ||
+      file_proto->file_info().is_directory() ||
+      cache_md5 != file_proto->file_specific_info().file_md5()) {
+    cache->RemoveOnUIThread(resource_id, CacheOperationCallback());
+    return;
+  }
+
+  // Otherwise, does nothing with the cache.
+}
+
+void GetCacheEntryAndRemoveCacheIfNecessary(
+    gdata::GDataFileSystemInterface* file_system,
+    gdata::GDataCache* cache,
+    const std::string& resource_id,
+    bool success,
+    const gdata::GDataCacheEntry& cache_entry) {
+  DCHECK(file_system);
+  DCHECK(cache);
+  DCHECK(BrowserThread::CurrentlyOn(BrowserThread::UI));
+
+  // Removes the chehe if GetCacheEntryOnUIThread() is failed.
+  if (!success) {
+    cache->RemoveOnUIThread(resource_id, CacheOperationCallback());
+    return;
+  }
+
+  file_system->GetEntryInfoByResourceId(resource_id,
+                                        base::Bind(&RemoveCacheIfNecessary,
+                                                   resource_id,
+                                                   cache,
+                                                   cache_entry.md5()));
+}
+
+}  // namespace
+
+StaleCacheFilesRemover::StaleCacheFilesRemover(
+    GDataFileSystemInterface* file_system,
+    GDataCache* cache)
+    : file_system_(file_system),
+      cache_(cache),
+      weak_ptr_factory_(this) {
+}
+
+StaleCacheFilesRemover::~StaleCacheFilesRemover() {
+}
+
+// Sets the timer to start scrubing.
+void StaleCacheFilesRemover::ScrubCacheAfterDelay() {
+  DCHECK(BrowserThread::CurrentlyOn(BrowserThread::UI));
+
+  base::MessageLoopProxy::current()->PostDelayedTask(
+      FROM_HERE,
+      base::Bind(&StaleCacheFilesRemover::ScrubCache,
+                 weak_ptr_factory_.GetWeakPtr()),
+      base::TimeDelta::FromSeconds(kDriveScrubDelayAfterFirstFeedFetch));
+}
+
+void StaleCacheFilesRemover::ScrubCache() {

[satorux1, 2012/08/10 23:47:40]

Because it's delayed, it's not guaranteed that cache_ and file_system_ are valid
by the time this function is called (i.e. they may be already deleted).

I think we should change the strategy here... The easiest way to solve this
problem is to implement this feature inside of GDataFileSystem, but we don't
want to add more code there. let me think a bit about it.

+  DCHECK(BrowserThread::CurrentlyOn(BrowserThread::UI));
+
+  const FilePath root_path = FilePath(gdata::kGDataRootDirectory);
+  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,
+        "",  // Doesn't check MD5.
+        base::Bind(&GetCacheEntryAndRemoveCacheIfNecessary,
+                   file_system_,
+                   cache_,
+                   resource_id));
+  }
+  MessageLoop::current()->DeleteSoon(FROM_HERE, this);
+}
+
+}  // namespace gdata