DomStorage data deletion and memory purging.

webkit/dom_storage/dom_storage_database.cc

Index: webkit/dom_storage/dom_storage_database.cc
===================================================================
--- webkit/dom_storage/dom_storage_database.cc	(revision 127981)
+++ webkit/dom_storage/dom_storage_database.cc	(working copy)
@@ -13,6 +13,8 @@
 
 namespace {
 
+const FilePath::CharType kJournal[] = FILE_PATH_LITERAL("-journal");
+
 class HistogramUniquifier {
  public:
   static const char* name() { return "Sqlite.DomStorageDatabase.Error"; }
@@ -26,14 +28,19 @@
 
 namespace dom_storage {
 
+// static
+FilePath DomStorageDatabase::GetJournalFilePath(
+    const FilePath& database_path) {
+  FilePath::StringType journal_file_name =
+      database_path.BaseName().value() + kJournal;
+  return database_path.DirName().Append(journal_file_name);
+}
+
 DomStorageDatabase::DomStorageDatabase(const FilePath& file_path)
     : file_path_(file_path) {
   // Note: in normal use we should never get an empty backing path here.
-  // However, the unit test for this class defines another constructor
-  // that will bypass this check to allow an empty path that signifies
-  // we should operate on an in-memory database for performance/reliability
-  // reasons.
-  DCHECK(!file_path_.empty());
+  // However, the unit test for this class can contruct an instance
+  // with an empty path.
   Init();
 }
 
@@ -49,9 +56,10 @@
 
 DomStorageDatabase::~DomStorageDatabase() {
   if (known_to_be_empty_ && !file_path_.empty()) {
-    // Delete the db from disk, it's empty.
+    // Delete the db and any lingering journal file from disk.
     Close();
     file_util::Delete(file_path_, false);
+    file_util::Delete(GetJournalFilePath(file_path_), false);
   }
 }
 
@@ -74,8 +82,12 @@
 
 bool DomStorageDatabase::CommitChanges(bool clear_all_first,
                                        const ValuesMap& changes) {
-  if (!LazyOpen(!changes.empty()))
-    return false;
+  if (!LazyOpen(!changes.empty())) {
+    // If we're being asked to commit changes that will result in an
+    // empty database, we return true if the database file doesn't exist.

[michaeln, 2012/03/22 23:03:32]

unittests turned this one up, lazyopen would return false since we set the
'create' flag to false and the file didn't exist... then this method would
return false indicating the commit failed

+    return clear_all_first && changes.empty() &&
+           !file_util::PathExists(file_path_);
+  }
 
   bool old_known_to_be_empty = known_to_be_empty_;
   sql::Transaction transaction(db_.get());