AppCache: If we can't read the existing data delete it and start over.

BUG=38360
TEST=some unit tests apply, but no new tests for this specifically

Review URL: http://codereview.chromium.org/1562005

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@43371 0039d316-1c4b-4281-b951-d872f2087c98

5 files changed, 76 insertions, 2 deletions

diff --git a/webkit/appcache/appcache_database.cc b/webkit/appcache/appcache_database.cc
index a1aa59b..a93b744 100644
--- a/webkit/appcache/appcache_database.cc
+++ b/webkit/appcache/appcache_database.cc
@@ -13,6 +13,7 @@
 #include "base/logging.h"
 #include "base/utf_string_conversions.h"
 #include "webkit/appcache/appcache_entry.h"
+#include "webkit/appcache/appcache_histograms.h"
 #include "webkit/database/quota_table.h"
 
 // Schema -------------------------------------------------------------------
@@ -994,10 +995,22 @@ bool AppCacheDatabase::LazyOpen(bool create_if_needed) {
   }
 
   if (!opened || !EnsureDatabaseVersion()) {
+    LOG(ERROR) << "Failed to open the appcache database.";
+    AppCacheHistograms::CountInitResult(
+        AppCacheHistograms::SQL_DATABASE_ERROR);
+
+    // We're unable to open the database. This is a fatal error
+    // which we can't recover from. We try to handle it by deleting
+    // the existing appcache data and starting with a clean slate in
+    // this browser session.
+    if (!use_in_memory_db && DeleteExistingAndCreateNewDatabase())
+      return true;
+
     Disable();
     return false;
   }
 
+  AppCacheHistograms::CountInitResult(AppCacheHistograms::INIT_OK);
   return true;
 }
 
@@ -1078,6 +1091,7 @@ void AppCacheDatabase::ResetConnectionAndTables() {
 bool AppCacheDatabase::DeleteExistingAndCreateNewDatabase() {
   DCHECK(!db_file_path_.empty());
   DCHECK(file_util::PathExists(db_file_path_));
+  LOG(INFO) << "Deleting existing appcache data and starting over.";
 
   ResetConnectionAndTables();
 
diff --git a/webkit/appcache/appcache_histograms.cc b/webkit/appcache/appcache_histograms.cc
new file mode 100644
index 0000000..9907047
--- /dev/null
+++ b/webkit/appcache/appcache_histograms.cc
@@ -0,0 +1,18 @@
+// Copyright (c) 2010 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/appcache/appcache_histograms.h"
+
+#include "base/histogram.h"
+
+namespace appcache {
+
+// static
+void AppCacheHistograms::CountInitResult(InitResultType init_result) {
+  UMA_HISTOGRAM_ENUMERATION(
+       "appcache.InitResult",
+       init_result, NUM_INIT_RESULT_TYPES);
+}
+
+}  // namespace appcache
diff --git a/webkit/appcache/appcache_histograms.h b/webkit/appcache/appcache_histograms.h
new file mode 100644
index 0000000..431c6bd
--- /dev/null
+++ b/webkit/appcache/appcache_histograms.h
@@ -0,0 +1,21 @@
+// Copyright (c) 2010 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.
+
+#ifndef WEBKIT_APPCACHE_APPCACHE_HISTOGRAMS_H_
+#define WEBKIT_APPCACHE_APPCACHE_HISTOGRAMS_H_
+
+namespace appcache {
+
+class AppCacheHistograms {
+ public:
+  enum InitResultType {
+    INIT_OK, SQL_DATABASE_ERROR, DISK_CACHE_ERROR,
+    NUM_INIT_RESULT_TYPES
+  };
+  static void CountInitResult(InitResultType init_result);
+};
+
+}  // namespace appcache
+
+#endif  // WEBKIT_APPCACHE_APPCACHE_HISTOGRAMS_H_
diff --git a/webkit/appcache/appcache_storage_impl.cc b/webkit/appcache/appcache_storage_impl.cc
index d700d24c..10724eb 100644
--- a/webkit/appcache/appcache_storage_impl.cc
+++ b/webkit/appcache/appcache_storage_impl.cc
@@ -17,11 +17,19 @@
 #include "webkit/appcache/appcache_database.h"
 #include "webkit/appcache/appcache_entry.h"
 #include "webkit/appcache/appcache_group.h"
+#include "webkit/appcache/appcache_histograms.h"
 #include "webkit/appcache/appcache_policy.h"
 #include "webkit/appcache/appcache_response.h"
 #include "webkit/appcache/appcache_service.h"
 #include "webkit/appcache/appcache_thread.h"
 
+namespace {
+// Helper with no return value for use with NewRunnableFunction.
+void DeleteDirectory(const FilePath& path) {
+  file_util::Delete(path, true);
+}
+}
+
 namespace appcache {
 
 static const char kAppCacheDatabaseName[] = "Index";
@@ -1275,9 +1283,19 @@ AppCacheDiskCache* AppCacheStorageImpl::disk_cache() {
 
 void AppCacheStorageImpl::OnDiskCacheInitialized(int rv) {
   if (rv != net::OK) {
-    // TODO(michaeln): We're unable to open the disk cache, how
-    // do we recover from this error?
+    LOG(ERROR) << "Failed to open the appcache diskcache.";
+    AppCacheHistograms::CountInitResult(AppCacheHistograms::DISK_CACHE_ERROR);
+
+    // We're unable to open the disk cache, this is a fatal error that we can't
+    // really recover from. We handle it by disabling the appcache for this
+    // browser session and deleting the directory on disk. The next browser
+    // session should start with a clean slate.
     Disable();
+    if (!is_incognito_) {
+      LOG(INFO) << "Deleting existing appcache data and starting over.";
+      AppCacheThread::PostTask(AppCacheThread::db(), FROM_HERE,
+          NewRunnableFunction(DeleteDirectory, cache_directory_));
+    }
   }
 }
 
diff --git a/webkit/appcache/webkit_appcache.gypi b/webkit/appcache/webkit_appcache.gypi
index 968c525..e3d5d902 100644
--- a/webkit/appcache/webkit_appcache.gypi
+++ b/webkit/appcache/webkit_appcache.gypi
@@ -27,6 +27,8 @@
         'appcache_frontend_impl.h',
         'appcache_group.cc',
         'appcache_group.h',
+        'appcache_histograms.cc',
+        'appcache_histograms.h',
         'appcache_host.cc',
         'appcache_host.h',
         'appcache_interceptor.cc',
@@ -60,6 +62,7 @@
         'view_appcache_internals_job.cc',
         'web_application_cache_host_impl.cc',
         'web_application_cache_host_impl.h',
+        'webkit_appcache.gypi',
       ],
       'conditions': [
         ['inside_chromium_build==0', {