1.1 --- /dev/null Thu Jan 01 00:00:00 1970 +0000
1.2 +++ b/security/sandbox/chromium/base/sequenced_task_runner_helpers.h Wed Dec 31 06:09:35 2014 +0100
1.3 @@ -0,0 +1,112 @@
1.4 +// Copyright (c) 2012 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_SEQUENCED_TASK_RUNNER_HELPERS_H_
1.9 +#define BASE_SEQUENCED_TASK_RUNNER_HELPERS_H_
1.10 +
1.11 +#include "base/basictypes.h"
1.12 +
1.13 +// TODO(akalin): Investigate whether it's possible to just have
1.14 +// SequencedTaskRunner use these helpers (instead of MessageLoop).
1.15 +// Then we can just move these to sequenced_task_runner.h.
1.16 +
1.17 +namespace tracked_objects {
1.18 +class Location;
1.19 +}
1.20 +
1.21 +namespace base {
1.22 +
1.23 +namespace subtle {
1.24 +template <class T, class R> class DeleteHelperInternal;
1.25 +template <class T, class R> class ReleaseHelperInternal;
1.26 +}
1.27 +
1.28 +// Template helpers which use function indirection to erase T from the
1.29 +// function signature while still remembering it so we can call the
1.30 +// correct destructor/release function.
1.31 +//
1.32 +// We use this trick so we don't need to include bind.h in a header
1.33 +// file like sequenced_task_runner.h. We also wrap the helpers in a
1.34 +// templated class to make it easier for users of DeleteSoon to
1.35 +// declare the helper as a friend.
1.36 +template <class T>
1.37 +class DeleteHelper {
1.38 + private:
1.39 + template <class T2, class R> friend class subtle::DeleteHelperInternal;
1.40 +
1.41 + static void DoDelete(const void* object) {
1.42 + delete reinterpret_cast<const T*>(object);
1.43 + }
1.44 +
1.45 + DISALLOW_COPY_AND_ASSIGN(DeleteHelper);
1.46 +};
1.47 +
1.48 +template <class T>
1.49 +class ReleaseHelper {
1.50 + private:
1.51 + template <class T2, class R> friend class subtle::ReleaseHelperInternal;
1.52 +
1.53 + static void DoRelease(const void* object) {
1.54 + reinterpret_cast<const T*>(object)->Release();
1.55 + }
1.56 +
1.57 + DISALLOW_COPY_AND_ASSIGN(ReleaseHelper);
1.58 +};
1.59 +
1.60 +namespace subtle {
1.61 +
1.62 +// An internal SequencedTaskRunner-like class helper for DeleteHelper
1.63 +// and ReleaseHelper. We don't want to expose the Do*() functions
1.64 +// directly directly since the void* argument makes it possible to
1.65 +// pass/ an object of the wrong type to delete. Instead, we force
1.66 +// callers to go through these internal helpers for type
1.67 +// safety. SequencedTaskRunner-like classes which expose DeleteSoon or
1.68 +// ReleaseSoon methods should friend the appropriate helper and
1.69 +// implement a corresponding *Internal method with the following
1.70 +// signature:
1.71 +//
1.72 +// bool(const tracked_objects::Location&,
1.73 +// void(*function)(const void*),
1.74 +// void* object)
1.75 +//
1.76 +// An implementation of this function should simply create a
1.77 +// base::Closure from (function, object) and return the result of
1.78 +// posting the task.
1.79 +template <class T, class ReturnType>
1.80 +class DeleteHelperInternal {
1.81 + public:
1.82 + template <class SequencedTaskRunnerType>
1.83 + static ReturnType DeleteViaSequencedTaskRunner(
1.84 + SequencedTaskRunnerType* sequenced_task_runner,
1.85 + const tracked_objects::Location& from_here,
1.86 + const T* object) {
1.87 + return sequenced_task_runner->DeleteSoonInternal(
1.88 + from_here, &DeleteHelper<T>::DoDelete, object);
1.89 + }
1.90 +
1.91 + private:
1.92 + DISALLOW_COPY_AND_ASSIGN(DeleteHelperInternal);
1.93 +};
1.94 +
1.95 +template <class T, class ReturnType>
1.96 +class ReleaseHelperInternal {
1.97 + public:
1.98 + template <class SequencedTaskRunnerType>
1.99 + static ReturnType ReleaseViaSequencedTaskRunner(
1.100 + SequencedTaskRunnerType* sequenced_task_runner,
1.101 + const tracked_objects::Location& from_here,
1.102 + const T* object) {
1.103 + return sequenced_task_runner->ReleaseSoonInternal(
1.104 + from_here, &ReleaseHelper<T>::DoRelease, object);
1.105 + }
1.106 +
1.107 + private:
1.108 + DISALLOW_COPY_AND_ASSIGN(ReleaseHelperInternal);
1.109 +};
1.110 +
1.111 +} // namespace subtle
1.112 +
1.113 +} // namespace base
1.114 +
1.115 +#endif // BASE_SEQUENCED_TASK_RUNNER_HELPERS_H_
