1.1 --- /dev/null Thu Jan 01 00:00:00 1970 +0000
1.2 +++ b/ipc/chromium/src/base/revocable_store.h Wed Dec 31 06:09:35 2014 +0100
1.3 @@ -0,0 +1,74 @@
1.4 +// Copyright (c) 2006-2008 The Chromium Authors. All rights reserved.
1.5 +// Use of this source code is governed by a BSD-style license that can be
1.6 +// found in the LICENSE file.
1.7 +
1.8 +#ifndef BASE_REVOCABLE_STORE_H_
1.9 +#define BASE_REVOCABLE_STORE_H_
1.10 +
1.11 +#include "base/ref_counted.h"
1.12 +
1.13 +// |RevocableStore| is a container of items that can be removed from the store.
1.14 +class RevocableStore {
1.15 + public:
1.16 + // A |StoreRef| is used to link the |RevocableStore| to its items. There is
1.17 + // one StoreRef per store, and each item holds a reference to it. If the
1.18 + // store wishes to revoke its items, it sets |store_| to null. Items are
1.19 + // permitted to release their reference to the |StoreRef| when they no longer
1.20 + // require the store.
1.21 + class StoreRef : public base::RefCounted<StoreRef> {
1.22 + public:
1.23 + StoreRef(RevocableStore* store) : store_(store) { }
1.24 +
1.25 + void set_store(RevocableStore* store) { store_ = store; }
1.26 + RevocableStore* store() const { return store_; }
1.27 +
1.28 + private:
1.29 + RevocableStore* store_;
1.30 +
1.31 + DISALLOW_EVIL_CONSTRUCTORS(StoreRef);
1.32 + };
1.33 +
1.34 + // An item in the store. On construction, the object adds itself to the
1.35 + // store.
1.36 + class Revocable {
1.37 + public:
1.38 + Revocable(RevocableStore* store);
1.39 + ~Revocable();
1.40 +
1.41 + // This item has been revoked if it no longer has a pointer to the store.
1.42 + bool revoked() const { return !store_reference_->store(); }
1.43 +
1.44 + private:
1.45 + // We hold a reference to the store through this ref pointer. We release
1.46 + // this reference on destruction.
1.47 + scoped_refptr<StoreRef> store_reference_;
1.48 +
1.49 + DISALLOW_EVIL_CONSTRUCTORS(Revocable);
1.50 + };
1.51 +
1.52 + RevocableStore();
1.53 + ~RevocableStore();
1.54 +
1.55 + // Revokes all the items in the store.
1.56 + void RevokeAll();
1.57 +
1.58 + // Returns true if there are no items in the store.
1.59 + bool empty() const { return count_ == 0; }
1.60 +
1.61 + private:
1.62 + friend class Revocable;
1.63 +
1.64 + // Adds an item to the store. To add an item to the store, construct it
1.65 + // with a pointer to the store.
1.66 + void Add(Revocable* item);
1.67 +
1.68 + // This is the reference the unrevoked items in the store hold.
1.69 + scoped_refptr<StoreRef> owning_reference_;
1.70 +
1.71 + // The number of unrevoked items in the store.
1.72 + int count_;
1.73 +
1.74 + DISALLOW_EVIL_CONSTRUCTORS(RevocableStore);
1.75 +};
1.76 +
1.77 +#endif // BASE_REVOCABLE_STORE_H_
