Support for recovering from corrupt cache database.

BUG=137545,148752
TEST=unit tests.
Review URL: https://codereview.chromium.org/10941027

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@157611 0039d316-1c4b-4281-b951-d872f2087c98

3 files changed, 44 insertions, 12 deletions

diff --git a/chrome/browser/chromeos/gdata/drive_cache_metadata.cc b/chrome/browser/chromeos/gdata/drive_cache_metadata.cc
index f5ce959..28527df 100644
--- a/chrome/browser/chromeos/gdata/drive_cache_metadata.cc
+++ b/chrome/browser/chromeos/gdata/drive_cache_metadata.cc
@@ -19,9 +19,6 @@ namespace {
 // A map table of resource ID to file path.
 typedef std::map<std::string, FilePath> ResourceIdToFilePathMap;
 
-const FilePath::CharType kDriveCacheMetadataDBPath[] =
-    FILE_PATH_LITERAL("cache_metadata.db");
-
 // Returns true if |file_path| is a valid symbolic link as |sub_dir_type|.
 // Otherwise, returns false with the reason.
 bool IsValidSymbolicLink(const FilePath& file_path,
@@ -459,25 +456,32 @@ void DriveCacheMetadataDB::Initialize(
           kDriveCacheMetadataDBPath);
   DVLOG(1) << "db path=" << db_path.value();
 
-  const bool db_exists = file_util::PathExists(db_path);
+  bool scan_cache = !file_util::PathExists(db_path);
 
   leveldb::DB* level_db = NULL;
   leveldb::Options options;
   options.create_if_missing = true;
   leveldb::Status db_status = leveldb::DB::Open(options, db_path.value(),
                                                 &level_db);
+
+  // Delete the db and scan the physical cache. This will fix a corrupt db, but
+  // perhaps not other causes of failed DB::Open.
+  if (!db_status.ok()) {
+    DVLOG(1) << "Detected corrupt db";
+    const bool deleted = file_util::Delete(db_path, true);
+    DCHECK(deleted);
+    db_status = leveldb::DB::Open(options, db_path.value(), &level_db);
+    // TODO(satorux): Handle the situation where DB::Open fails because of lack
+    // of disk space, permissions, or other causes. crbug.com/150840.
+    CHECK(db_status.ok());  // Must succeed or we'll crash later.
+    scan_cache = true;
+  }
   DCHECK(level_db);
-  // TODO(achuith,hashimoto,satorux): If db cannot be opened, we should try to
-  // recover it. If that fails, we should just delete it and either rescan or
-  // refetch the feed. crbug.com/137545.
-  DCHECK(db_status.ok());
   level_db_.reset(level_db);
 
   // We scan the cache directories to initialize the cache database if we
   // were previously using the cache map.
-  // TODO(achuith,hashimoto,satorux): Delete ScanCachePaths in M23.
-  // crbug.com/137542
-  if (!db_exists) {
+  if (scan_cache) {
     CacheMap cache_map;
     ScanCachePaths(cache_paths, &cache_map);
     InsertMapIntoDB(cache_map);
@@ -579,6 +583,11 @@ void DriveCacheMetadataDB::ForceRescanForTesting(
 
 }  // namespace
 
+// static
+const FilePath::CharType* DriveCacheMetadata::kDriveCacheMetadataDBPath =
+    FILE_PATH_LITERAL("cache_metadata.db");
+
+
 DriveCacheMetadata::DriveCacheMetadata(
     base::SequencedTaskRunner* blocking_task_runner)
     : blocking_task_runner_(blocking_task_runner) {
diff --git a/chrome/browser/chromeos/gdata/drive_cache_metadata.h b/chrome/browser/chromeos/gdata/drive_cache_metadata.h
index 47d54a6..66e2e55 100644
--- a/chrome/browser/chromeos/gdata/drive_cache_metadata.h
+++ b/chrome/browser/chromeos/gdata/drive_cache_metadata.h
@@ -28,6 +28,9 @@ class DriveCacheMetadata {
   // A map table of cache file's resource id to its CacheEntry* entry.
   typedef std::map<std::string, DriveCacheEntry> CacheMap;
 
+  // Database path.
+  static const FilePath::CharType* kDriveCacheMetadataDBPath;
+
   virtual ~DriveCacheMetadata();
 
   // Creates DriveCacheMetadata instance.
diff --git a/chrome/browser/chromeos/gdata/drive_cache_metadata_unittest.cc b/chrome/browser/chromeos/gdata/drive_cache_metadata_unittest.cc
index bfcffb5..cefe04c 100644
--- a/chrome/browser/chromeos/gdata/drive_cache_metadata_unittest.cc
+++ b/chrome/browser/chromeos/gdata/drive_cache_metadata_unittest.cc
@@ -347,7 +347,7 @@ TEST_F(DriveCacheMetadataTest, Initialization) {
 }
 
 // Test DriveCacheMetadata::RemoveTemporaryFiles.
-TEST_F(DriveCacheMetadataTest, RemoveTemporaryFilesTest) {
+TEST_F(DriveCacheMetadataTest, RemoveTemporaryFiles) {
   SetUpCacheMetadata();
 
   DriveCacheMetadata::CacheMap cache_map;
@@ -388,4 +388,24 @@ TEST_F(DriveCacheMetadataTest, RemoveTemporaryFilesTest) {
   EXPECT_FALSE(metadata_->GetCacheEntry("<resource_id_4>", "", &cache_entry));
 }
 
+TEST_F(DriveCacheMetadataTest, CorruptDB) {
+  SetUpCacheWithVariousFiles();
+
+  const FilePath db_path = cache_paths_[DriveCache::CACHE_TYPE_META].Append(
+      DriveCacheMetadata::kDriveCacheMetadataDBPath);
+
+  // Write a bogus file.
+  std::string text("Hello world");
+  file_util::WriteFile(db_path, text.c_str(), text.length());
+
+  SetUpCacheMetadata();
+
+  // "id_foo" is present and pinned.
+  DriveCacheEntry cache_entry;
+  ASSERT_TRUE(metadata_->GetCacheEntry("id_foo", "md5foo", &cache_entry));
+  EXPECT_EQ("md5foo", cache_entry.md5());
+  EXPECT_EQ(DriveCache::CACHE_TYPE_PERSISTENT,
+            DriveCache::GetSubDirectoryType(cache_entry));
+}
+
 }  // namespace gdata