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 a5321942a7dd26d504c33ce033970ae621f105c1..217daf8ead879932f743e5cf68a88145d3a32152 100644
--- a/webkit/dom_storage/dom_storage_area.cc
+++ b/webkit/dom_storage/dom_storage_area.cc
@@ -15,6 +15,8 @@
 #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"
 
@@ -72,16 +74,23 @@ DomStorageArea::DomStorageArea(
     int64 namespace_id,
     const std::string& persistent_namespace_id,
     const GURL& origin,
+    SessionStorageDatabase* session_storage_backing,
     DomStorageTaskRunner* task_runner)
     : namespace_id_(namespace_id),
       persistent_namespace_id_(persistent_namespace_id),
       origin_(origin),
       task_runner_(task_runner),
       map_(new DomStorageMap(kPerAreaQuota + kPerAreaOverQuotaAllowance)),
+      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, persistent_namespace_id, origin));
+    is_initial_import_done_ = false;
+  }
 }
 
 DomStorageArea::~DomStorageArea() {
@@ -168,13 +177,19 @@ DomStorageArea* DomStorageArea::ShallowCopy(
     const std::string& destination_persistent_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, destination_persistent_namespace_id, origin_,
-      task_runner_);
+      session_storage_backing_, task_runner_);
   copy->map_ = map_;
   copy->is_shutdown_ = is_shutdown_;

[michaeln, 2012/06/26 06:15:12]

since map_ is populated, should we set is_initial_import_done_ to true here?

[marja, 2012/06/26 14:18:05]

Done.

+
+  // 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;
 }
 
@@ -195,10 +210,22 @@ void DomStorageArea::DeleteOrigin() {
     return;
   }
   map_ = new DomStorageMap(kPerAreaQuota + kPerAreaOverQuotaAllowance);
-  if (backing_.get()) {
+  if (backing_.get() && !session_storage_backing_.get()) {
+    // This is localStorage.
     is_initial_import_done_ = false;
     backing_->Reset();
     backing_->DeleteFiles();
+  } else if (session_storage_backing_.get()) {
+    // No need to read the data (there will be no data), also, the
+    // PRIMARY_SEQUENCE thread shouldn't try to read the data while
+    // SessionStorageDatabase::DeleteArea is in progress.
+    is_initial_import_done_ = true;
+    task_runner_->PostShutdownBlockingTask(
+        FROM_HERE,
+        DomStorageTaskRunner::COMMIT_SEQUENCE,
+        base::Bind(base::IgnoreResult(&SessionStorageDatabase::DeleteArea),
+                   session_storage_backing_.get(),
+                   persistent_namespace_id_, origin_));
   }
 }
 
@@ -236,7 +263,6 @@ void DomStorageArea::InitialImportIfNeeded() {
   if (is_initial_import_done_)
     return;
 
-  DCHECK_EQ(kLocalStorageNamespaceId, namespace_id_);
   DCHECK(backing_.get());
 
   ValuesMap initial_values;
@@ -264,13 +290,15 @@ 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.
@@ -298,9 +326,9 @@ 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(
@@ -323,6 +351,7 @@ void DomStorageArea::ShutdownInCommitSequence() {
   }
   commit_batch_.reset();
   backing_.reset();
+  session_storage_backing_ = NULL;
 }
 
 }  // namespace dom_storage