Persist sessionStorage on disk.

webkit/dom_storage/dom_storage_context.cc

 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "webkit/dom_storage/dom_storage_context.h"
 
 #include "base/bind.h"
 #include "base/bind_helpers.h"
 #include "base/file_util.h"
 #include "base/guid.h"
 #include "base/location.h"
 #include "base/time.h"
 #include "webkit/dom_storage/dom_storage_area.h"
 #include "webkit/dom_storage/dom_storage_database.h"
 #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;
 
 namespace dom_storage {
 
+static const int kSessionStoraceScavengingSeconds = 60;
+
 DomStorageContext::UsageInfo::UsageInfo() : data_size(0) {}
 DomStorageContext::UsageInfo::~UsageInfo() {}
 
 DomStorageContext::DomStorageContext(
     const FilePath& localstorage_directory,
     const FilePath& sessionstorage_directory,
     quota::SpecialStoragePolicy* special_storage_policy,
     DomStorageTaskRunner* task_runner)
     : localstorage_directory_(localstorage_directory),
       sessionstorage_directory_(sessionstorage_directory),
       task_runner_(task_runner),
       is_shutdown_(false),
       force_keep_session_state_(false),
-      special_storage_policy_(special_storage_policy) {
+      special_storage_policy_(special_storage_policy),
+      scavenging_started_(false) {
   // AtomicSequenceNum starts at 0 but we want to start session
   // namespace ids at one since zero is reserved for the
   // kLocalStorageNamespaceId.
   session_id_sequence_.GetNext();
+  if (!sessionstorage_directory_.empty()) {
+    session_storage_database_ = new SessionStorageDatabase(
+        sessionstorage_directory_);
+  }
 }
 
 DomStorageContext::~DomStorageContext() {
 }
 
 DomStorageNamespace* DomStorageContext::GetStorageNamespace(
     int64 namespace_id) {
   if (is_shutdown_)
     return NULL;
   StorageNamespaceMap::iterator found = namespaces_.find(namespace_id);
@@ skipping 29 matching lines @@
       info.origin = DomStorageArea::OriginFromDatabaseFileName(path);
       if (include_file_info) {
         FileEnumerator::FindInfo find_info;
         enumerator.GetFindInfo(&find_info);
         info.data_size = FileEnumerator::GetFilesize(find_info);
         info.last_modified = FileEnumerator::GetLastModifiedTime(find_info);
       }
       infos->push_back(info);
     }
   }
+  // TODO(marja): Get usage infos for sessionStorage (crbug.com/123599).
 }
 
 void DomStorageContext::DeleteOrigin(const GURL& origin) {
   DCHECK(!is_shutdown_);
   DomStorageNamespace* local = GetStorageNamespace(kLocalStorageNamespaceId);
   local->DeleteOrigin(origin);
 }
 
 void DomStorageContext::PurgeMemory() {
   // We can only purge memory from the local storage namespace
   // which is backed by disk.
   StorageNamespaceMap::iterator found =
       namespaces_.find(kLocalStorageNamespaceId);
   if (found != namespaces_.end())
     found->second->PurgeMemory();
 }
 
 void DomStorageContext::Shutdown() {
   is_shutdown_ = true;
   StorageNamespaceMap::const_iterator it = namespaces_.begin();
   for (; it != namespaces_.end(); ++it)
     it->second->Shutdown();
 
-  if (localstorage_directory_.empty())
+  if (localstorage_directory_.empty() && !session_storage_database_.get())
     return;
 
   // Respect the content policy settings about what to
   // keep and what to discard.
   if (force_keep_session_state_)
     return;  // Keep everything.
 
   bool has_session_only_origins =
       special_storage_policy_.get() &&
       special_storage_policy_->HasSessionOnlyOrigins();
@@ skipping 54 matching lines @@
 }
 
 void DomStorageContext::CreateSessionNamespace(
     int64 namespace_id,
     const std::string& persistent_namespace_id) {
   if (is_shutdown_)
     return;
   DCHECK(namespace_id != kLocalStorageNamespaceId);
   DCHECK(namespaces_.find(namespace_id) == namespaces_.end());
   namespaces_[namespace_id] = new DomStorageNamespace(
-      namespace_id, persistent_namespace_id, task_runner_);
+      namespace_id, persistent_namespace_id, session_storage_database_.get(),
+      task_runner_);
 }
 
 void DomStorageContext::DeleteSessionNamespace(
     int64 namespace_id, bool should_persist_data) {
   DCHECK_NE(kLocalStorageNamespaceId, namespace_id);
-  // TODO(marja): Protect the sessionStorage data (once it's written on disk).
+  StorageNamespaceMap::const_iterator it = namespaces_.find(namespace_id);
+  if (it == namespaces_.end())
+    return;
+  std::string persistent_namespace_id = it->second->persistent_namespace_id();
+  if (session_storage_database_.get()) {
+    if (!should_persist_data) {
+      bool success = task_runner_->PostShutdownBlockingTask(
+          FROM_HERE,
+          DomStorageTaskRunner::COMMIT_SEQUENCE,
+          base::Bind(
+              base::IgnoreResult(&SessionStorageDatabase::DeleteNamespace),
+              session_storage_database_,
+              persistent_namespace_id));
+      DCHECK(success);
+    } else if (!scavenging_started_) {
+      // Protect the persistent namespace ID from scavenging.
+      protected_persistent_session_ids_.insert(persistent_namespace_id);
+    }
+  }
   namespaces_.erase(namespace_id);
 }
 
 void DomStorageContext::CloneSessionNamespace(
     int64 existing_id, int64 new_id,
     const std::string& new_persistent_id) {
   if (is_shutdown_)
     return;
   DCHECK_NE(kLocalStorageNamespaceId, existing_id);
   DCHECK_NE(kLocalStorageNamespaceId, new_id);
   StorageNamespaceMap::iterator found = namespaces_.find(existing_id);
   if (found != namespaces_.end())
     namespaces_[new_id] = found->second->Clone(new_id, new_persistent_id);
   else
     CreateSessionNamespace(new_id, new_persistent_id);
 }
 
 void DomStorageContext::ClearSessionOnlyOrigins() {
-  std::vector<UsageInfo> infos;
-  const bool kDontIncludeFileInfo = false;
-  GetUsageInfo(&infos, kDontIncludeFileInfo);
-  for (size_t i = 0; i < infos.size(); ++i) {
-    const GURL& origin = infos[i].origin;
-    if (special_storage_policy_->IsStorageProtected(origin))
-      continue;
-    if (!special_storage_policy_->IsStorageSessionOnly(origin))
-      continue;
+  if (!localstorage_directory_.empty()) {
+    std::vector<UsageInfo> infos;
+    const bool kDontIncludeFileInfo = false;
+    GetUsageInfo(&infos, kDontIncludeFileInfo);
+    for (size_t i = 0; i < infos.size(); ++i) {
+      const GURL& origin = infos[i].origin;
+      if (special_storage_policy_->IsStorageProtected(origin))
+        continue;
+      if (!special_storage_policy_->IsStorageSessionOnly(origin))
+        continue;
 
-    const bool kNotRecursive = false;
-    FilePath database_file_path = localstorage_directory_.Append(
-        DomStorageArea::DatabaseFileNameFromOrigin(origin));
-    file_util::Delete(database_file_path, kNotRecursive);
-    file_util::Delete(
-        DomStorageDatabase::GetJournalFilePath(database_file_path),
-        kNotRecursive);
+      const bool kNotRecursive = false;
+      FilePath database_file_path = localstorage_directory_.Append(
+          DomStorageArea::DatabaseFileNameFromOrigin(origin));
+      file_util::Delete(database_file_path, kNotRecursive);
+      file_util::Delete(
+          DomStorageDatabase::GetJournalFilePath(database_file_path),
+          kNotRecursive);
+    }
+  }
+  if (session_storage_database_.get()) {
+    std::vector<std::string> namespace_ids;
+    session_storage_database_->ReadNamespaceIds(&namespace_ids);
+    for (std::vector<std::string>::const_iterator it = namespace_ids.begin();
+         it != namespace_ids.end(); ++it) {
+      std::vector<GURL> origins;
+      session_storage_database_->ReadOriginsInNamespace(*it, &origins);
+
+      for (std::vector<GURL>::const_iterator origin_it = origins.begin();
+           origin_it != origins.end(); ++origin_it) {
+        if (special_storage_policy_->IsStorageProtected(*origin_it))
+          continue;
+        if (!special_storage_policy_->IsStorageSessionOnly(*origin_it))
+          continue;
+        session_storage_database_->DeleteArea(*it, *origin_it);
+      }
+    }
   }
 }
 
+void DomStorageContext::StartScavengingUnusedSessionStorage() {

[michaeln, 2012/07/10 01:16:58]

any chance this can be called more than once? maybe early return if
scavenging_started_

[marja, 2012/07/10 13:40:52]

I moved reading the atm-in-use namespaces forward in time (FindUnusedNamespace),
since that's the latest point in this thread that we can read the info. Also,
scavenging_started_ is set there, and it posts a task in the COMMIT_SEQUENCE to
read the DB.

Now, if a namespace is created, data is written to it, and it's deleted, the
data won't be written into the DB before we read the DB for finding unused
namespaces (since the next thing that will happen in the COMMIT_SEQUENCE) is
FindUnusedNamespaceInCommitSequence.

So this version cannot delete data by accident, afaics...

+  if (session_storage_database_.get()) {
+    std::set<std::string> namespace_ids_in_use;
+    for (StorageNamespaceMap::const_iterator it = namespaces_.begin();
+         it != namespaces_.end(); ++it)
+      namespace_ids_in_use.insert(it->second->persistent_namespace_id());
+    std::set<std::string> protected_persistent_session_ids;
+    protected_persistent_session_ids.swap(protected_persistent_session_ids_);
+    bool success = task_runner_->PostDelayedTask(
+        FROM_HERE, base::Bind(
+            &DomStorageContext::FindUnusedSessionStorage,
+            this, namespace_ids_in_use, protected_persistent_session_ids_),

[michaeln, 2012/07/10 01:16:58]

you'll need to nix the _ on the protected_persistent_session_ids_ param in this
method call

[marja, 2012/07/10 13:40:52]

Done.

+        base::TimeDelta::FromSeconds(kSessionStoraceScavengingSeconds));
+    DCHECK(success);
+    scavenging_started_ = true;
+  }
+}
+
+void DomStorageContext::FindUnusedSessionStorage(
+    const std::set<std::string>& namespace_ids_in_use,
+    const std::set<std::string>& protected_persistent_session_ids) {
+  if (session_storage_database_.get()) {
+    bool success = task_runner_->PostShutdownBlockingTask(
+        FROM_HERE, DomStorageTaskRunner::COMMIT_SEQUENCE,
+        base::Bind(
+            &DomStorageContext::FindUnusedSessionStorageInCommitSequence,

[michaeln, 2012/07/10 01:16:58]

Is there a window of time between StartScavenging and this call where other
namespaces can be created/deleted and not get added to the protected collection?

[marja, 2012/07/10 13:40:52]

This problem should be solved now, pls see above.

+            this, namespace_ids_in_use, protected_persistent_session_ids));
+    DCHECK(success);
+  }
+}
+
+void DomStorageContext::FindUnusedSessionStorageInCommitSequence(
+    const std::set<std::string>& namespace_ids_in_use,
+    const std::set<std::string>& protected_persistent_session_ids) {
+  DCHECK(session_storage_database_.get());
+  // Delete all namespaces which don't have an associated DomStorageNamespace
+  // alive.
+  std::vector<std::string> namespace_ids;
+  session_storage_database_->ReadNamespaceIds(&namespace_ids);
+  for (std::vector<std::string>::const_iterator it = namespace_ids.begin();
+       it != namespace_ids.end(); ++it) {
+    if (namespace_ids_in_use.find(*it) == namespace_ids_in_use.end() &&
+        protected_persistent_session_ids.find(*it) ==
+        protected_persistent_session_ids.end()) {
+      deletable_persistent_namespace_ids_.push_back(*it);
+    }
+  }
+  if (!deletable_persistent_namespace_ids_.empty()) {
+    bool success = task_runner_->PostDelayedTask(
+        FROM_HERE, base::Bind(
+            &DomStorageContext::DeleteNextUnunsedNamespace,
+            this),
+        base::TimeDelta::FromSeconds(kSessionStoraceScavengingSeconds));
+    DCHECK(success);
+  }
+}
+
+void DomStorageContext::DeleteNextUnunsedNamespace() {
+  if (is_shutdown_)
+    return;
+  bool success = task_runner_->PostShutdownBlockingTask(
+        FROM_HERE, DomStorageTaskRunner::COMMIT_SEQUENCE,
+        base::Bind(&DomStorageContext::DeleteNextUnunsedNamespace,
+                   this));
+  DCHECK(success);
+}
+
+void DomStorageContext::DeleteNextUnunsedNamespaceInCommitSequence() {
+  const std::string& persistent_id = deletable_persistent_namespace_ids_.back();
+  session_storage_database_->DeleteNamespace(persistent_id);
+  deletable_persistent_namespace_ids_.pop_back();
+  if (!deletable_persistent_namespace_ids_.empty()) {
+    bool success = task_runner_->PostDelayedTask(
+        FROM_HERE, base::Bind(
+            &DomStorageContext::DeleteNextUnunsedNamespace,
+            this),
+        base::TimeDelta::FromSeconds(kSessionStoraceScavengingSeconds));
+    DCHECK(success);
+  }
+}
+
 }  // namespace dom_storage