base/mac/scoped_nsexception_enabler.h

   1 // Copyright (c) 2011 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 #ifndef BASE_MAC_SCOPED_NSEXCEPTION_ENABLER_H_
   6 #define BASE_MAC_SCOPED_NSEXCEPTION_ENABLER_H_
   7 #pragma once
   8
   9 #include "base/basictypes.h"
  10
  11 namespace base {
  12 namespace mac {
  13
  14 // BrowserCrApplication attempts to restrict throwing of NSExceptions
  15 // because they interact badly with C++ scoping rules.  Unfortunately,
  16 // there are some cases where exceptions must be supported, such as
  17 // when third-party printer drivers are used.  These helpers can be
  18 // used to enable exceptions for narrow windows.
  19
  20 // Make it easy to safely allow NSException to be thrown in a limited
  21 // scope.  Note that if an exception is thrown, then this object will
  22 // not be appropriately destructed!  If the exception ends up in the
  23 // top-level event loop, things are cleared in -reportException:.  If
  24 // the exception is caught at a lower level, a higher level scoper
  25 // should eventually reset things.
  26 class ScopedNSExceptionEnabler {
  27  public:
  28   ScopedNSExceptionEnabler();
  29   ~ScopedNSExceptionEnabler();
  30
  31  private:
  32   bool was_enabled_;
  33
  34   DISALLOW_COPY_AND_ASSIGN(ScopedNSExceptionEnabler);
  35 };
  36
  37 // Access the exception setting for the current thread.  This is for
  38 // the support code in BrowserCrApplication, other code should use
  39 // the scoper.
  40 bool GetNSExceptionsAllowed();
  41 void SetNSExceptionsAllowed(bool allowed);
  42
  43 }  // namespace mac
  44 }  // namespace base
  45
  46 #endif  // BASE_MAC_SCOPED_NSEXCEPTION_ENABLER_H_