Persist sessionStorage on disk.

webkit/dom_storage/dom_storage_area.cc

Index: webkit/dom_storage/dom_storage_area.cc
diff --git a/webkit/dom_storage/dom_storage_area.cc b/webkit/dom_storage/dom_storage_area.cc
index 43f22f16cc7debb89f1ddf36d8001ed3f7df1f07..df18cdeee37601ab81a2c4ed705be7a2645293ba 100644
--- a/webkit/dom_storage/dom_storage_area.cc
+++ b/webkit/dom_storage/dom_storage_area.cc
@@ -5,7 +5,6 @@
 #include "webkit/dom_storage/dom_storage_area.h"
 
 #include "base/bind.h"
-#include "base/file_util.h"
 #include "base/location.h"
 #include "base/logging.h"
 #include "base/time.h"
@@ -15,6 +14,9 @@
 #include "webkit/dom_storage/dom_storage_namespace.h"
 #include "webkit/dom_storage/dom_storage_task_runner.h"
 #include "webkit/dom_storage/dom_storage_types.h"
+#include "webkit/dom_storage/local_storage_database_adapter.h"
+#include "webkit/dom_storage/session_storage_database.h"
+#include "webkit/dom_storage/session_storage_database_adapter.h"
 #include "webkit/fileapi/file_system_util.h"
 #include "webkit/glue/webkit_glue.h"
 
@@ -62,9 +64,29 @@ DomStorageArea::DomStorageArea(
       is_initial_import_done_(true),
       is_shutdown_(false),
       commit_batches_in_flight_(0) {
-  if (namespace_id == kLocalStorageNamespaceId && !directory.empty()) {
+  DCHECK_EQ(kLocalStorageNamespaceId, namespace_id);
+  if (!directory.empty()) {
     FilePath path = directory.Append(DatabaseFileNameFromOrigin(origin_));
-    backing_.reset(new DomStorageDatabase(path));
+    backing_.reset(new LocalStorageDatabaseAdapter(path));
+    is_initial_import_done_ = false;
+  }
+}
+
+DomStorageArea::DomStorageArea(
+    int64 namespace_id, const GURL& origin,
+    SessionStorageDatabase* session_storage_backing,
+    DomStorageTaskRunner* task_runner)
+    : namespace_id_(namespace_id), origin_(origin),
+      task_runner_(task_runner),
+      map_(new DomStorageMap(kPerAreaQuota)),
+      session_storage_backing_(session_storage_backing),
+      is_initial_import_done_(true),
+      is_shutdown_(false),
+      commit_batches_in_flight_(0) {
+  DCHECK(namespace_id != kLocalStorageNamespaceId);
+  if (session_storage_backing) {
+    backing_.reset(new SessionStorageDatabaseAdapter(
+        session_storage_backing, namespace_id, origin));
     is_initial_import_done_ = false;
   }
 }
@@ -151,12 +173,19 @@ bool DomStorageArea::Clear() {
 DomStorageArea* DomStorageArea::ShallowCopy(int64 destination_namespace_id) {
   DCHECK_NE(kLocalStorageNamespaceId, namespace_id_);
   DCHECK_NE(kLocalStorageNamespaceId, destination_namespace_id);
-  DCHECK(!backing_.get());  // SessionNamespaces aren't stored on disk.
 
-  DomStorageArea* copy = new DomStorageArea(destination_namespace_id, origin_,
-                                            FilePath(), task_runner_);
+  DomStorageArea* copy = new DomStorageArea(
+      destination_namespace_id, origin_, session_storage_backing_,
+      task_runner_);
   copy->map_ = map_;
   copy->is_shutdown_ = is_shutdown_;
+
+  // All the uncommitted changes to this area need to happen before the actual
+  // shallow copy is made (scheduled by the upper layer). Another OnCommitTimer
+  // call might be in the event queue at this point, but it's handled gracefully
+  // when it fires.
+  if (commit_batch_.get())
+    OnCommitTimer();
   return copy;
 }
 
@@ -177,12 +206,18 @@ void DomStorageArea::DeleteOrigin() {
     return;
   }
   map_ = new DomStorageMap(kPerAreaQuota);
-  if (backing_.get()) {
+  if (backing_.get() && !session_storage_backing_.get()) {
+    // This is localStorage.
     is_initial_import_done_ = false;
-    backing_.reset(new DomStorageDatabase(backing_->file_path()));
-    file_util::Delete(backing_->file_path(), false);
-    file_util::Delete(
-        DomStorageDatabase::GetJournalFilePath(backing_->file_path()), false);
+    backing_->Reset();
+    backing_->DeleteFiles();
+  } else if (session_storage_backing_.get()) {
+    task_runner_->PostShutdownBlockingTask(
+        FROM_HERE,
+        DomStorageTaskRunner::COMMIT_SEQUENCE,
+        base::Bind(base::IgnoreResult(&SessionStorageDatabase::DeleteArea),
+                   session_storage_backing_.get(),
+                   namespace_id_, origin_));
   }
 }
 
@@ -199,7 +234,7 @@ void DomStorageArea::PurgeMemory() {
 
   // Recreate the database object, this frees up the open sqlite connection
   // and its page cache.
-  backing_.reset(new DomStorageDatabase(backing_->file_path()));
+  backing_->Reset();
 }
 
 void DomStorageArea::Shutdown() {
@@ -220,7 +255,6 @@ void DomStorageArea::InitialImportIfNeeded() {
   if (is_initial_import_done_)
     return;
 
-  DCHECK_EQ(kLocalStorageNamespaceId, namespace_id_);
   DCHECK(backing_.get());
 
   ValuesMap initial_values;
@@ -248,13 +282,15 @@ DomStorageArea::CommitBatch* DomStorageArea::CreateCommitBatchIfNeeded() {
 }
 
 void DomStorageArea::OnCommitTimer() {
-  DCHECK_EQ(kLocalStorageNamespaceId, namespace_id_);
   if (is_shutdown_)
     return;
 
   DCHECK(backing_.get());
-  DCHECK(commit_batch_.get());
-  DCHECK(!commit_batches_in_flight_);
+
+  // It's possible that there is nothing to commit, since a shallow copy occured
+  // before the timer fired.
+  if (!commit_batch_.get())
+    return;
 
   // This method executes on the primary sequence, we schedule
   // a task for immediate execution on the commit sequence.
@@ -282,9 +318,9 @@ void DomStorageArea::CommitChanges(const CommitBatch* commit_batch) {
 void DomStorageArea::OnCommitComplete() {
   // We're back on the primary sequence in this method.
   DCHECK(task_runner_->IsRunningOnPrimarySequence());
+  --commit_batches_in_flight_;
   if (is_shutdown_)
     return;
-  --commit_batches_in_flight_;
   if (commit_batch_.get() && !commit_batches_in_flight_) {
     // More changes have accrued, restart the timer.
     task_runner_->PostDelayedTask(
@@ -307,6 +343,7 @@ void DomStorageArea::ShutdownInCommitSequence() {
   }
   commit_batch_.reset();
   backing_.reset();
+  session_storage_backing_ = NULL;
 }
 
 }  // namespace dom_storage