1 // Copyright (c) 2012 The Chromium Authors. All rights reserved. 2 // Use of this source code is governed by a BSD-style license that can be 3 // found in the LICENSE file. 4 5 #import "base/mac/scoped_nsexception_enabler.h" 6 7 #import "base/lazy_instance.h" 8 #import "base/threading/thread_local.h" 9 10 // To make the |g_exceptionsAllowed| declaration readable. 11 using base::LazyInstance; 12 using base::ThreadLocalBoolean; 13 14 // When C++ exceptions are disabled, the C++ library defines |try| and 15 // |catch| so as to allow exception-expecting C++ code to build properly when 16 // language support for exceptions is not present. These macros interfere 17 // with the use of |@try| and |@catch| in Objective-C files such as this one. 18 // Undefine these macros here, after everything has been #included, since 19 // there will be no C++ uses and only Objective-C uses from this point on. 20 #undef try 21 #undef catch 22 23 namespace { 24 25 // Whether to allow NSExceptions to be raised on the current thread. 26 LazyInstance<ThreadLocalBoolean>::Leaky 27 g_exceptionsAllowed = LAZY_INSTANCE_INITIALIZER; 28 29 } // namespace 30 31 namespace base { 32 namespace mac { 33 34 bool GetNSExceptionsAllowed() { 35 return g_exceptionsAllowed.Get().Get(); 36 } 37 38 void SetNSExceptionsAllowed(bool allowed) { 39 return g_exceptionsAllowed.Get().Set(allowed); 40 } 41 42 id RunBlockIgnoringExceptions(BlockReturningId block) { 43 id ret = nil; 44 @try { 45 base::mac::ScopedNSExceptionEnabler enable; 46 ret = block(); 47 } 48 @catch(id exception) { 49 } 50 return ret; 51 } 52 53 ScopedNSExceptionEnabler::ScopedNSExceptionEnabler() { 54 was_enabled_ = GetNSExceptionsAllowed(); 55 SetNSExceptionsAllowed(true); 56 } 57 58 ScopedNSExceptionEnabler::~ScopedNSExceptionEnabler() { 59 SetNSExceptionsAllowed(was_enabled_); 60 } 61 62 } // namespace mac 63 } // namespace base 64
