| Index: base/thread_restrictions.h
|
| ===================================================================
|
| --- base/thread_restrictions.h (revision 70342)
|
| +++ base/thread_restrictions.h (working copy)
|
| @@ -1,100 +0,0 @@
|
| -// Copyright (c) 2010 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.
|
| -
|
| -#ifndef BASE_THREAD_RESTRICTIONS_H_
|
| -#define BASE_THREAD_RESTRICTIONS_H_
|
| -
|
| -#include "base/basictypes.h"
|
| -
|
| -namespace base {
|
| -
|
| -// Certain behavior is disallowed on certain threads. ThreadRestrictions helps
|
| -// enforce these rules. Examples of such rules:
|
| -//
|
| -// * Do not do blocking IO (makes the thread janky)
|
| -// * Do not access Singleton/LazyInstance (may lead to shutdown crashes)
|
| -//
|
| -// Here's more about how the protection works:
|
| -//
|
| -// 1) If a thread should not be allowed to make IO calls, mark it:
|
| -// base::ThreadRestrictions::SetIOAllowed(false);
|
| -// By default, threads *are* allowed to make IO calls.
|
| -// In Chrome browser code, IO calls should be proxied to the File thread.
|
| -//
|
| -// 2) If a function makes a call that will go out to disk, check whether the
|
| -// current thread is allowed:
|
| -// base::ThreadRestrictions::AssertIOAllowed();
|
| -//
|
| -// ThreadRestrictions does nothing in release builds; it is debug-only.
|
| -//
|
| -// Style tip: where should you put AssertIOAllowed checks? It's best
|
| -// if you put them as close to the disk access as possible, at the
|
| -// lowest level. This rule is simple to follow and helps catch all
|
| -// callers. For example, if your function GoDoSomeBlockingDiskCall()
|
| -// only calls other functions in Chrome and not fopen(), you should go
|
| -// add the AssertIOAllowed checks in the helper functions.
|
| -
|
| -class ThreadRestrictions {
|
| - public:
|
| - // Constructing a ScopedAllowIO temporarily allows IO for the current
|
| - // thread. Doing this is almost certainly always incorrect.
|
| - class ScopedAllowIO {
|
| - public:
|
| - ScopedAllowIO() { previous_value_ = SetIOAllowed(true); }
|
| - ~ScopedAllowIO() { SetIOAllowed(previous_value_); }
|
| - private:
|
| - // Whether IO is allowed when the ScopedAllowIO was constructed.
|
| - bool previous_value_;
|
| -
|
| - DISALLOW_COPY_AND_ASSIGN(ScopedAllowIO);
|
| - };
|
| -
|
| - // Constructing a ScopedAllowSingleton temporarily allows accessing for the
|
| - // current thread. Doing this is almost always incorrect.
|
| - class ScopedAllowSingleton {
|
| - public:
|
| - ScopedAllowSingleton() { previous_value_ = SetSingletonAllowed(true); }
|
| - ~ScopedAllowSingleton() { SetSingletonAllowed(previous_value_); }
|
| - private:
|
| - // Whether singleton use is allowed when the ScopedAllowSingleton was
|
| - // constructed.
|
| - bool previous_value_;
|
| -
|
| - DISALLOW_COPY_AND_ASSIGN(ScopedAllowSingleton);
|
| - };
|
| -
|
| -#ifndef NDEBUG
|
| - // Set whether the current thread to make IO calls.
|
| - // Threads start out in the *allowed* state.
|
| - // Returns the previous value.
|
| - static bool SetIOAllowed(bool allowed);
|
| -
|
| - // Check whether the current thread is allowed to make IO calls,
|
| - // and DCHECK if not. See the block comment above the class for
|
| - // a discussion of where to add these checks.
|
| - static void AssertIOAllowed();
|
| -
|
| - // Set whether the current thread can use singletons. Returns the previous
|
| - // value.
|
| - static bool SetSingletonAllowed(bool allowed);
|
| -
|
| - // Check whether the current thread is allowed to use singletons (Singleton /
|
| - // LazyInstance). DCHECKs if not.
|
| - static void AssertSingletonAllowed();
|
| -#else
|
| - // In Release builds, inline the empty definitions of these functions so
|
| - // that they can be compiled out.
|
| - static bool SetIOAllowed(bool allowed) { return true; }
|
| - static void AssertIOAllowed() {}
|
| - static bool SetSingletonAllowed(bool allowed) { return true; }
|
| - static void AssertSingletonAllowed() {}
|
| -#endif
|
| -
|
| - private:
|
| - DISALLOW_IMPLICIT_CONSTRUCTORS(ThreadRestrictions);
|
| -};
|
| -
|
| -} // namespace base
|
| -
|
| -#endif // BASE_THREAD_RESTRICTIONS_H_
|
|
|