Persist sessionStorage on disk.

webkit/dom_storage/dom_storage_context.cc

Index: webkit/dom_storage/dom_storage_context.cc
diff --git a/webkit/dom_storage/dom_storage_context.cc b/webkit/dom_storage/dom_storage_context.cc
index 78363d437469a597abc6b280edc309d819bdd085..cc305990cc14f7026b6992fe94439f7a03f3486f 100644
--- a/webkit/dom_storage/dom_storage_context.cc
+++ b/webkit/dom_storage/dom_storage_context.cc
@@ -13,6 +13,7 @@
 #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/session_storage_database.h"
 #include "webkit/quota/special_storage_policy.h"
 
 using file_util::FileEnumerator;
@@ -36,6 +37,16 @@ DomStorageContext::DomStorageContext(
   // namespace ids at one since zero is reserved for the
   // kLocalStorageNamespaceId.
   session_id_sequence_.GetNext();
+  // FIXME(marja): hack.
+  if (!directory_.empty()) {
+    session_storage_database_ =
+        new SessionStorageDatabase(directory.Append("Session Storage"));
+    // Delete the possible leftover data from previous run from the session
+    // storage.
+    // TODO(marja): When doing a session restore, protect parts of the data from
+    // deletion and call this when we know if a session restore will happen.
+    session_storage_database_->DeleteLeftoverData();

[michaeln, 2012/04/12 01:48:46]

This constructor is invoked on the UI thread in chrome early on during profile
creation. We definitely don't want to do a lot of IO at this early time. The
DeleteLeftoverData method results in lots of IO.

[marja, 2012/04/19 10:20:50]

Yes, this was wrong.

If we crash, DeleteSessionNamespace()s won't be called, and we have leftover
data. When should such data be deleted? On the next startup? Or on the next
clean exit? (Atm, I put it to Shutdown().)

+  }
 }
 
 DomStorageContext::~DomStorageContext() {
@@ -84,6 +95,7 @@ void DomStorageContext::GetUsageInfo(std::vector<UsageInfo>* infos,
       infos->push_back(info);
     }
   }
+  // FIXME(marja): Get usage infos for sessionStorage.

[michaeln, 2012/04/12 01:48:46]

The content settings ui doesn't show anything about session storage data
currently and the DeleteOrigin and DeleteDataModifiedSince methods only apply to
localstorage atm. Eventually blending in info about 'sessionstorage' usage is a
possibility.

Maybe open a bug for this instead of having a TODO buried in this class since it
also involves changes to the UI layer and programming interfaces used between
here and there?

[marja, 2012/04/19 10:20:50]

Done. crbug.com/123599

 }
 
 void DomStorageContext::DeleteOrigin(const GURL& origin) {
@@ -188,8 +200,15 @@ void DomStorageContext::CreateSessionNamespace(
     return;
   DCHECK(namespace_id != kLocalStorageNamespaceId);
   DCHECK(namespaces_.find(namespace_id) == namespaces_.end());
-  namespaces_[namespace_id] = new DomStorageNamespace(
-      namespace_id, task_runner_);
+  if (session_storage_database_.get()) {
+    // Session storage with backing.
+    namespaces_[namespace_id] = new DomStorageNamespace(
+        namespace_id, session_storage_database_.get(), task_runner_);
+  } else {
+    // Session storage without backing.
+    namespaces_[namespace_id] = new DomStorageNamespace(
+        namespace_id, task_runner_);
+  }
 }
 
 void DomStorageContext::DeleteSessionNamespace(
@@ -229,7 +248,7 @@ void DomStorageContext::ClearLocalStateInCommitSequence() {
         DomStorageArea::DatabaseFileNameFromOrigin(origin));
     file_util::Delete(database_file_path, kNotRecursive);
     file_util::Delete(
-        DomStorageDatabase::GetJournalFilePath(database_file_path),
+        LocalStorageDatabase::GetJournalFilePath(database_file_path),
         kNotRecursive);
   }
 }