AppCaches which belong to hosted apps are not protected from deletion

content/browser/appcache/chrome_appcache_service.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 "content/browser/appcache/chrome_appcache_service.h"
 
 #include "base/file_path.h"
 #include "base/file_util.h"
 #include "content/browser/content_browser_client.h"
 #include "content/common/notification_service.h"
 #include "net/base/net_errors.h"
 #include "webkit/appcache/appcache_thread.h"
 #include "webkit/quota/quota_manager.h"
 
 static bool has_initialized_thread_ids;
 
-namespace {
-
-// Used to defer deleting of local storage until the destructor has finished.
-void DeleteLocalStateOnIOThread(FilePath cache_path) {
-  // Post the actual deletion to the DB thread to ensure it happens after the
-  // database file has been closed.
-  BrowserThread::PostTask(
-      BrowserThread::DB, FROM_HERE,
-      NewRunnableFunction<bool(*)(const FilePath&, bool), FilePath, bool>(
-          &file_util::Delete, cache_path, true));
-}
-
-}  // namespace
-
 // ----------------------------------------------------------------------------
 
 ChromeAppCacheService::ChromeAppCacheService(
     quota::QuotaManagerProxy* quota_manager_proxy)
     : AppCacheService(quota_manager_proxy),
-      resource_context_(NULL), clear_local_state_on_exit_(false) {
+      resource_context_(NULL),
+      ALLOW_THIS_IN_INITIALIZER_LIST(appcache_got_info_callback_(
+          this, &ChromeAppCacheService::OnGotAppCacheInfo)),
+      ALLOW_THIS_IN_INITIALIZER_LIST(origin_deleted_callback_(
+          this, &ChromeAppCacheService::OnOriginDeleted)),
+      origins_to_be_deleted_count_(0),
+      appcaches_cleared_event_(new base::WaitableEvent(true, false)),
+      appcaches_cleared_callback_(NULL),
+      waiting_for_clear_appcaches_(false) {
 }
 
 void ChromeAppCacheService::InitializeOnIOThread(
     const FilePath& cache_path,
     const content::ResourceContext* resource_context,
-    scoped_refptr<quota::SpecialStoragePolicy> special_storage_policy,
-    bool clear_local_state_on_exit) {
+    scoped_refptr<quota::SpecialStoragePolicy> special_storage_policy) {
   DCHECK(BrowserThread::CurrentlyOn(BrowserThread::IO));
 
   if (!has_initialized_thread_ids) {
     has_initialized_thread_ids = true;
     appcache::AppCacheThread::Init(BrowserThread::DB, BrowserThread::IO);
   }
 
   cache_path_ = cache_path;
   resource_context_ = resource_context;
   registrar_.Add(
       this, content::NOTIFICATION_PURGE_MEMORY,
       NotificationService::AllSources());
-  SetClearLocalStateOnExit(clear_local_state_on_exit);
 
   // Init our base class.
   Initialize(cache_path_,
              BrowserThread::GetMessageLoopProxyForThread(BrowserThread::CACHE));
   set_appcache_policy(this);
   set_special_storage_policy(special_storage_policy);
 }
 
 ChromeAppCacheService::~ChromeAppCacheService() {
-  DCHECK(BrowserThread::CurrentlyOn(BrowserThread::IO));
-
-  if (clear_local_state_on_exit_ && !cache_path_.empty()) {
-    BrowserThread::PostTask(
-        BrowserThread::IO, FROM_HERE,
-        NewRunnableFunction(DeleteLocalStateOnIOThread, cache_path_));
-  }
 }
 
-void ChromeAppCacheService::SetClearLocalStateOnExit(bool clear_local_state) {
-  // TODO(michaeln): How is 'protected' status granted to apps in this case?
+base::WaitableEvent* ChromeAppCacheService::ClearAppCache(
+    net::CompletionCallback* callback)
+{
   if (!BrowserThread::CurrentlyOn(BrowserThread::IO)) {
     BrowserThread::PostTask(
-        BrowserThread::IO, FROM_HERE,
-        NewRunnableMethod(this,
-                          &ChromeAppCacheService::SetClearLocalStateOnExit,
-                          clear_local_state));
-    return;
+      BrowserThread::IO, FROM_HERE,
+      NewRunnableMethod(this,
+                        &ChromeAppCacheService::ClearAppCache,
+                        callback));
+    return appcaches_cleared_event_.get();
   }
-  clear_local_state_on_exit_ = clear_local_state;
+
+  // Only one appcache deletion should be in progress at any given time.
+  DCHECK(waiting_for_clear_appcaches_ == false);
+  waiting_for_clear_appcaches_ = true;
+  appcaches_cleared_callback_ = callback;
+  appcaches_cleared_event_->Reset();
+
+  // Keep the ChromeAppCacheService instance alive until the deletion has
+  // finished.
+  AddRef();
+
+  appcache_info_ = new appcache::AppCacheInfoCollection;
+  GetAllAppCacheInfo(
+      appcache_info_, &appcache_got_info_callback_);
+  // Continues in OnGotAppCacheInfo.
+
+  return appcaches_cleared_event_.get();
+}
+
+void ChromeAppCacheService::OnGotAppCacheInfo(int rv) {
+  using appcache::AppCacheInfoVector;
+  typedef std::map<GURL, AppCacheInfoVector> InfoByOrigin;
+
+  origins_to_be_deleted_count_ = 0;
+  for (InfoByOrigin::const_iterator origin =
+           appcache_info_->infos_by_origin.begin();
+       origin != appcache_info_->infos_by_origin.end(); ++origin) {
+
+    if (special_storage_policy_->IsStorageProtected(origin->first))
+      continue;
+
+    ++origins_to_be_deleted_count_;
+    DeleteAppCachesForOrigin(origin->first, &origin_deleted_callback_);
+  }
+
+  if (origins_to_be_deleted_count_ == 0)
+    OnClearedAppCache();
+  // Else continues in OnOriginDeleted.
+}
+
+void ChromeAppCacheService::OnOriginDeleted(int rv) {
+  --origins_to_be_deleted_count_;
+  if (origins_to_be_deleted_count_ == 0)
+    OnClearedAppCache();
+}
+
+void ChromeAppCacheService::OnClearedAppCache() {

[michaeln, 2011/07/12 18:45:38]

Fyi, at the time this callback is invoked, the responses may have not (likely
have not) actually been removed from the DiskCache. The responses are lazily
scavenged after the Group/Cache/Entry records have been deleted, this completion
callback occurs when those records have been deleted by prior to the scavenging
having taken place. 

+  appcaches_cleared_event_->Signal();
+  if (appcaches_cleared_callback_) {
+    appcaches_cleared_callback_->Run(0);
+  }
+  waiting_for_clear_appcaches_ = false;
+  Release();
 }
 
 bool ChromeAppCacheService::CanLoadAppCache(const GURL& manifest_url) {
   DCHECK(BrowserThread::CurrentlyOn(BrowserThread::IO));
   // We don't prompt for read access.
   return content::GetContentClient()->browser()->AllowAppCache(
       manifest_url, *resource_context_);
 }
 
 int ChromeAppCacheService::CanCreateAppCache(
@@ skipping 28 matching lines @@
     const tracked_objects::Location& from_here,
     Task* task) {
   return BrowserThread::PostTask(ToBrowserThreadID(id), from_here, task);
 }
 
 bool AppCacheThread::CurrentlyOn(int id) {
   return BrowserThread::CurrentlyOn(ToBrowserThreadID(id));
 }
 
 }  // namespace appcache