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[v3] use explicit operators in c++0x
- From: Benjamin Kosnik <bkoz at redhat dot com>
- To: gcc-patches at gcc dot gnu dot org
- Cc: libstdc++ at gcc dot gnu dot org
- Date: Wed, 20 May 2009 18:10:12 -0700
- Subject: [v3] use explicit operators in c++0x
Removes the various safe bool idioms in use, now that explicit
operator bool can be used with impunity. Should be current as of N2857.
tested x86_64/linux
-benjamin
2009-05-20 Benjamin Kosnik <bkoz@redhat.com>
* include/tr1_impl/functional (function): Use explicit operator bool.
* include/bits/shared_ptr.h (__shared_ptr): Same.
* include/bits/unique_ptr.h (unique_ptr): Same.
* include/std/mutex (unique_lock): Same.
* include/std/system_error (error_code): Same.
(error_condition): Same.
* include/std/ostream (sentry): Same.
* include/std/istream (sentry): Same.
* testsuite/19_diagnostics/error_condition/operators/bool.cc: Adjust.
* testsuite/19_diagnostics/error_condition/operators/bool_neg.cc: Same.
* testsuite/19_diagnostics/error_code/operators/bool.cc: Same.
* testsuite/19_diagnostics/error_code/operators/bool_neg.cc: Same.
* testsuite/20_util/unique_ptr/modifiers/reset_neg.cc: Same.
* testsuite/20_util/unique_ptr/assign/assign_neg.cc: Same.
* testsuite/20_util/shared_ptr/observers/bool_conv.cc: Same.
Index: include/tr1_impl/functional
===================================================================
--- include/tr1_impl/functional (revision 147755)
+++ include/tr1_impl/functional (working copy)
@@ -1761,6 +1761,7 @@
: public _Maybe_unary_or_binary_function<_Res, _ArgTypes...>,
private _Function_base
{
+#ifndef __GXX_EXPERIMENTAL_CXX0X__
/// This class is used to implement the safe_bool idiom.
struct _Hidden_type
{
@@ -1769,6 +1770,7 @@
/// This typedef is used to implement the safe_bool idiom.
typedef _Hidden_type* _Hidden_type::* _Safe_bool;
+#endif
typedef _Res _Signature_type(_ArgTypes...);
@@ -1918,6 +1920,10 @@
*
* This function will not throw an exception.
*/
+#ifdef __GXX_EXPERIMENTAL_CXX0X__
+ explicit operator bool() const
+ { return !_M_empty(); }
+#else
operator _Safe_bool() const
{
if (_M_empty())
@@ -1925,6 +1931,7 @@
else
return &_Hidden_type::_M_bool;
}
+#endif
// [3.7.2.4] function invocation
Index: include/std/system_error
===================================================================
--- include/std/system_error (revision 147755)
+++ include/std/system_error (working copy)
@@ -152,16 +152,9 @@
message() const
{ return category().message(value()); }
- // Safe bool idiom.
- // explicit operator bool() const throw()
- // { return _M_value != 0; }
- typedef void (*__bool_type)();
+ explicit operator bool() const
+ { return _M_value != 0 ? true : false; }
- static void __not_bool_type() { }
-
- operator __bool_type() const
- { return _M_value != 0 ? &__not_bool_type : false; }
-
// DR 804.
private:
int _M_value;
@@ -233,16 +226,9 @@
message() const
{ return category().message(value()); }
- // Safe bool idiom.
- // explicit operator bool() const throw()
- // { return _M_value != 0; }
- typedef void (*__bool_type)();
+ explicit operator bool() const
+ { return _M_value != 0 ? true : false; }
- static void __not_bool_type() { }
-
- operator __bool_type() const
- { return _M_value != 0 ? &__not_bool_type : false; }
-
// DR 804.
private:
int _M_value;
Index: include/std/mutex
===================================================================
--- include/std/mutex (revision 147755)
+++ include/std/mutex (working copy)
@@ -574,7 +574,7 @@
owns_lock() const
{ return _M_owns; }
- /* explicit */ operator bool () const
+ explicit operator bool() const
{ return owns_lock(); }
mutex_type*
Index: include/std/istream
===================================================================
--- include/std/istream (revision 147755)
+++ include/std/istream (working copy)
@@ -631,6 +631,9 @@
template<typename _CharT, typename _Traits>
class basic_istream<_CharT, _Traits>::sentry
{
+ // Data Members.
+ bool _M_ok;
+
public:
/// Easy access to dependant types.
typedef _Traits traits_type;
@@ -670,11 +673,11 @@
* For ease of use, sentries may be converted to booleans. The
* return value is that of the sentry state (true == okay).
*/
+#ifdef __GXX_EXPERIMENTAL_CXX0X__
+ explicit
+#endif
operator bool() const
{ return _M_ok; }
-
- private:
- bool _M_ok;
};
// [27.6.1.2.3] character extraction templates
Index: include/std/ostream
===================================================================
--- include/std/ostream (revision 147755)
+++ include/std/ostream (working copy)
@@ -376,7 +376,7 @@
template <typename _CharT, typename _Traits>
class basic_ostream<_CharT, _Traits>::sentry
{
- // Data Members:
+ // Data Members.
bool _M_ok;
basic_ostream<_CharT, _Traits>& _M_os;
@@ -420,6 +420,9 @@
* For ease of use, sentries may be converted to booleans. The
* return value is that of the sentry state (true == okay).
*/
+#ifdef __GXX_EXPERIMENTAL_CXX0X__
+ explicit
+#endif
operator bool() const
{ return _M_ok; }
};
Index: include/bits/shared_ptr.h
===================================================================
--- include/bits/shared_ptr.h (revision 147755)
+++ include/bits/shared_ptr.h (working copy)
@@ -816,14 +816,9 @@
get() const // never throws
{ return _M_ptr; }
- // Implicit conversion to "bool"
- private:
- typedef _Tp* __shared_ptr::*__unspecified_bool_type;
+ explicit operator bool() const // never throws
+ { return _M_ptr == 0 ? false : true; }
- public:
- operator __unspecified_bool_type() const // never throws
- { return _M_ptr == 0 ? 0 : &__shared_ptr::_M_ptr; }
-
bool
unique() const // never throws
{ return _M_refcount._M_unique(); }
Index: include/bits/unique_ptr.h
===================================================================
--- include/bits/unique_ptr.h (revision 147755)
+++ include/bits/unique_ptr.h (working copy)
@@ -85,7 +85,6 @@
class unique_ptr
{
typedef std::tuple<_Tp*, _Tp_Deleter> __tuple_type;
- typedef __tuple_type unique_ptr::* __unspecified_bool_type;
typedef _Tp* unique_ptr::* __unspecified_pointer_type;
public:
@@ -181,8 +180,8 @@
get_deleter() const
{ return std::get<1>(_M_t); }
- operator __unspecified_bool_type () const
- { return get() == 0 ? 0 : &unique_ptr::_M_t; }
+ explicit operator bool() const
+ { return get() == 0 ? false : true; }
// Modifiers.
pointer
@@ -233,7 +232,6 @@
class unique_ptr<_Tp[], _Tp_Deleter>
{
typedef std::tuple<_Tp*, _Tp_Deleter> __tuple_type;
- typedef __tuple_type unique_ptr::* __unspecified_bool_type;
typedef _Tp* unique_ptr::* __unspecified_pointer_type;
public:
@@ -323,8 +321,8 @@
get_deleter() const
{ return std::get<1>(_M_t); }
- operator __unspecified_bool_type () const
- { return get() == 0 ? 0 : &unique_ptr::_M_t; }
+ explicit operator bool() const
+ { return get() == 0 ? false : true; }
// Modifiers.
pointer
Index: testsuite/19_diagnostics/error_condition/operators/bool.cc
===================================================================
--- testsuite/19_diagnostics/error_condition/operators/bool.cc (revision 147755)
+++ testsuite/19_diagnostics/error_condition/operators/bool.cc (working copy)
@@ -27,14 +27,14 @@
// 1
std::error_condition e1;
- if (e1)
+ if (static_cast<bool>(e1))
{
VERIFY( false );
}
// 2
std::error_condition e2(std::errc::operation_not_supported);
- if (e2)
+ if (static_cast<bool>(e2))
{
VERIFY( true );
}
Index: testsuite/19_diagnostics/error_condition/operators/bool_neg.cc
===================================================================
--- testsuite/19_diagnostics/error_condition/operators/bool_neg.cc (revision 147755)
+++ testsuite/19_diagnostics/error_condition/operators/bool_neg.cc (working copy)
@@ -29,4 +29,4 @@
return i;
}
-// { dg-error "invalid conversion" "" { target *-*-* } 27 }
+// { dg-error "could not convert" "" { target *-*-* } 27 }
Index: testsuite/19_diagnostics/error_code/operators/bool.cc
===================================================================
--- testsuite/19_diagnostics/error_code/operators/bool.cc (revision 147755)
+++ testsuite/19_diagnostics/error_code/operators/bool.cc (working copy)
@@ -28,14 +28,14 @@
// 1
std::error_code e1;
- if (e1)
+ if (static_cast<bool>(e1))
{
VERIFY( false );
}
// 2
std::error_code e2(std::make_error_code(std::errc::operation_not_supported));
- if (e2)
+ if (static_cast<bool>(e2))
{
VERIFY( true );
}
Index: testsuite/19_diagnostics/error_code/operators/bool_neg.cc
===================================================================
--- testsuite/19_diagnostics/error_code/operators/bool_neg.cc (revision 147755)
+++ testsuite/19_diagnostics/error_code/operators/bool_neg.cc (working copy)
@@ -30,4 +30,4 @@
return i;
}
-// { dg-error "invalid conversion" "" { target *-*-* } 28 }
+// { dg-error "could not convert" "" { target *-*-* } 28 }
Index: testsuite/20_util/unique_ptr/modifiers/reset_neg.cc
===================================================================
--- testsuite/20_util/unique_ptr/modifiers/reset_neg.cc (revision 147755)
+++ testsuite/20_util/unique_ptr/modifiers/reset_neg.cc (working copy)
@@ -36,4 +36,4 @@
}
// { dg-error "used here" "" { target *-*-* } 35 }
-// { dg-error "deleted function" "" { target *-*-* } 350 }
+// { dg-error "deleted function" "" { target *-*-* } 348 }
Index: testsuite/20_util/unique_ptr/assign/assign_neg.cc
===================================================================
--- testsuite/20_util/unique_ptr/assign/assign_neg.cc (revision 147755)
+++ testsuite/20_util/unique_ptr/assign/assign_neg.cc (working copy)
@@ -52,7 +52,7 @@
// { dg-error "used here" "" { target *-*-* } 42 }
// { dg-error "no matching" "" { target *-*-* } 48 }
// { dg-error "used here" "" { target *-*-* } 49 }
-// { dg-error "candidates are" "" { target *-*-* } 214 }
-// { dg-error "deleted function" "" { target *-*-* } 214 }
-// { dg-error "deleted function" "" { target *-*-* } 360 }
+// { dg-error "candidates are" "" { target *-*-* } 213 }
+// { dg-error "deleted function" "" { target *-*-* } 213 }
+// { dg-error "deleted function" "" { target *-*-* } 358 }
// { dg-excess-errors "note" }
Index: testsuite/20_util/shared_ptr/observers/bool_conv.cc
===================================================================
--- testsuite/20_util/shared_ptr/observers/bool_conv.cc (revision 147755)
+++ testsuite/20_util/shared_ptr/observers/bool_conv.cc (working copy)
@@ -33,9 +33,9 @@
bool test __attribute__((unused)) = true;
const std::shared_ptr<A> p1;
- VERIFY( p1 == false );
+ VERIFY( static_cast<bool>(p1) == false );
const std::shared_ptr<A> p2(p1);
- VERIFY( p2 == false );
+ VERIFY( static_cast<bool>(p2) == false );
}
void
@@ -44,12 +44,12 @@
bool test __attribute__((unused)) = true;
std::shared_ptr<A> p1(new A);
- VERIFY( p1 );
+ VERIFY( static_cast<bool>(p1) );
std::shared_ptr<A> p2(p1);
- VERIFY( p2 );
+ VERIFY( static_cast<bool>(p2) );
p1.reset();
- VERIFY( !p1 );
- VERIFY( p2 );
+ VERIFY( !static_cast<bool>(p1) );
+ VERIFY( static_cast<bool>(p2) );
}
void
@@ -60,8 +60,8 @@
std::shared_ptr<A> p1(new A);
std::shared_ptr<A> p2(p1);
p2.reset(new A);
- VERIFY( p1 );
- VERIFY( p2 );
+ VERIFY( static_cast<bool>(p1) );
+ VERIFY( static_cast<bool>(p2) );
}