Pull implementation of CertStore out to be reused.

content/browser/item_store.h

+// Copyright (c) 2012 The Chromium Authors. All rights reserved.

[agl, 2013/11/14 16:20:37]

2013

[alcutter, 2013/11/14 16:51:59]

Done.

+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#include <map>
+
+#include "base/bind.h"
+#include "base/stl_util.h"
+#include "base/synchronization/lock.h"
+#include "content/browser/renderer_host/render_process_host_impl.h"
+#include "content/browser/renderer_host/render_view_host_impl.h"
+#include "content/public/browser/browser_thread.h"
+#include "content/public/browser/notification_observer.h"
+#include "content/public/browser/notification_registrar.h"
+#include "content/public/browser/notification_service.h"
+#include "content/public/browser/notification_types.h"
+
+template <typename T>
+struct MatchSecond {
+  explicit MatchSecond(const T& t) : value(t) {}
+
+  template<typename Pair>
+  bool operator()(const Pair& p) const {
+    return (value == p.second);
+  }
+  T value;
+};
+
+namespace content {
+
+template<typename T>
+class ItemStore : public NotificationObserver {
+ protected:
+
+ItemStore() : next_item_id_(1) {

[agl, 2013/11/14 16:20:37]

this should be indented two spaces and then the body fixed up likewise.

[alcutter, 2013/11/14 16:51:59]

I think this should've already been done with the follow up clang-format patch.

+  if (BrowserThread::CurrentlyOn(BrowserThread::UI)) {
+    RegisterForNotification();
+  } else {
+    BrowserThread::PostTask(
+        BrowserThread::UI, FROM_HERE,
+        base::Bind(&ItemStore::RegisterForNotification,
+                   base::Unretained(this)));
+  }
+}
+
+virtual ~ItemStore() {
+}
+
+void RegisterForNotification() {
+  // We watch for RenderProcess termination, as this is how we clear
+  // items for now.
+  // TODO(jcampan): we should be listening to events such as resource cached/
+  //                removed from cache, and remove the item when we know it
+  //                is not used anymore.
+
+  registrar_.Add(this, NOTIFICATION_RENDERER_PROCESS_TERMINATED,
+                 NotificationService::AllBrowserContextsAndSources());
+  registrar_.Add(this, NOTIFICATION_RENDERER_PROCESS_CLOSED,
+                 NotificationService::AllBrowserContextsAndSources());
+}
+
+int Store(T* item, int process_id) {
+  DCHECK(item);
+  base::AutoLock auto_lock(lock_);
+
+  int item_id;
+
+  // Do we already know this item?
+  typename ReverseItemMap::iterator item_iter = item_to_id_.find(item);
+  if (item_iter == item_to_id_.end()) {
+    item_id = next_item_id_++;
+    // We use 0 as an invalid item_id value.  In the unlikely event that
+    // next_item_id_ wraps around, we reset it to 1.
+    if (next_item_id_ == 0)
+      next_item_id_ = 1;
+    item->AddRef();
+    id_to_item_[item_id] = item;
+    item_to_id_[item] = item_id;
+  } else {
+    item_id = item_iter->second;
+  }
+
+  // Let's update process_id_to_item_id_.
+  std::pair<IDMap::iterator, IDMap::iterator> process_ids =
+      process_id_to_item_id_.equal_range(process_id);
+  if (std::find_if(process_ids.first, process_ids.second,
+                   MatchSecond<int>(item_id)) == process_ids.second) {
+    process_id_to_item_id_.insert(std::make_pair(process_id, item_id));
+  }
+
+  // And item_id_to_process_id_.
+  std::pair<IDMap::iterator, IDMap::iterator> item_ids =
+      item_id_to_process_id_.equal_range(item_id);
+  if (std::find_if(item_ids.first, item_ids.second,
+                   MatchSecond<int>(process_id)) == item_ids.second) {
+    item_id_to_process_id_.insert(std::make_pair(item_id, process_id));
+  }
+
+  return item_id;
+}
+
+bool Retrieve(int item_id, scoped_refptr<T>* item) {
+  base::AutoLock auto_lock(lock_);
+
+  typename ItemMap::iterator iter = id_to_item_.find(item_id);
+  if (iter == id_to_item_.end())
+    return false;
+  if (item)
+    *item = iter->second;
+  return true;
+}
+
+void RemoveInternal(int item_id) {
+  typename ItemMap::iterator item_iter = id_to_item_.find(item_id);
+  DCHECK(item_iter != id_to_item_.end());
+
+  typename ReverseItemMap::iterator id_iter =
+      item_to_id_.find(item_iter->second.get());
+  DCHECK(id_iter != item_to_id_.end());
+  item_to_id_.erase(id_iter);
+
+  item_iter->second->Release();
+  id_to_item_.erase(item_iter);
+}
+
+void RemoveForRenderProcessHost(int process_id) {
+  base::AutoLock auto_lock(lock_);
+
+  // We iterate through all the item ids for that process.
+  std::pair<IDMap::iterator, IDMap::iterator> process_ids =
+      process_id_to_item_id_.equal_range(process_id);
+  for (IDMap::iterator ids_iter = process_ids.first;
+       ids_iter != process_ids.second; ++ids_iter) {
+    int item_id = ids_iter->second;
+    // Find all the processes referring to this item id in
+    // item_id_to_process_id_, then locate the process being removed within
+    // that range.
+    std::pair<IDMap::iterator, IDMap::iterator> item_ids =
+        item_id_to_process_id_.equal_range(item_id);
+    IDMap::iterator proc_iter =
+        std::find_if(item_ids.first, item_ids.second,
+                     MatchSecond<int>(process_id));
+    DCHECK(proc_iter != item_ids.second);
+
+    // Before removing, determine if no other processes refer to the current
+    // item id. If |proc_iter| (the current process) is the lower bound of
+    // processes containing the current item id and if |next_proc_iter| is the
+    // upper bound (the first process that does not), then only one process,
+    // the one being removed, refers to the item id.
+    IDMap::iterator next_proc_iter = proc_iter;
+    ++next_proc_iter;
+    bool last_process_for_item_id =
+        (proc_iter == item_ids.first && next_proc_iter == item_ids.second);
+    item_id_to_process_id_.erase(proc_iter);
+
+    if (last_process_for_item_id) {
+      // The current item id is not referenced by any other processes, so
+      // remove it from id_to_item_ and item_to_id_.
+      RemoveInternal(item_id);
+    }
+  }
+  if (process_ids.first != process_ids.second)
+    process_id_to_item_id_.erase(process_ids.first, process_ids.second);
+}
+
+void Observe(int type,
+                        const NotificationSource& source,
+                        const NotificationDetails& details) {
+  DCHECK(type == NOTIFICATION_RENDERER_PROCESS_TERMINATED ||
+         type == NOTIFICATION_RENDERER_PROCESS_CLOSED);
+  RenderProcessHost* rph = Source<RenderProcessHost>(source).ptr();
+  DCHECK(rph);
+  RemoveForRenderProcessHost(rph->GetID());
+}
+
+ protected:
+  typedef std::multimap<int, int> IDMap;
+  typedef std::map<int, scoped_refptr<T> > ItemMap;
+  typedef std::map<T*, int, typename T::LessThan> ReverseItemMap;
+
+  // Is only used on the UI Thread.
+  NotificationRegistrar registrar_;
+
+  IDMap process_id_to_item_id_;
+  IDMap item_id_to_process_id_;
+  ItemMap id_to_item_;
+  ReverseItemMap item_to_id_;
+
+  int next_item_id_;
+
+  // This lock protects: process_to_item_id_, item_id_to_process_id_,
+  //                     id_to_item_, and item_to_id_.
+  base::Lock lock_;
+};
+
+}  // namespace content