From 75271b73a8484cb5add003f65f1432c05c47dc8b Mon Sep 17 00:00:00 2001 From: Andrzej Krzemienski Date: Thu, 22 May 2014 23:32:49 +0200 Subject: [PATCH] Member fun value() that throws on uninitialized --- .../boost_optional/detailed_semantics.html | 37 ++++++ .../exception_safety_guarantees.html | 4 +- doc/html/boost_optional/synopsis.html | 3 + doc/html/index.html | 2 +- doc/reference.qbk | 28 +++++ doc/special_cases.qbk | 2 +- include/boost/bad_optional_access.hpp | 28 +++++ include/boost/optional/optional.hpp | 18 +++ include/boost/optional/optional_fwd.hpp | 2 - test/Jamfile.v2 | 1 + test/optional_test_value_access.cpp | 107 ++++++++++++++++++ 11 files changed, 226 insertions(+), 6 deletions(-) create mode 100644 include/boost/bad_optional_access.hpp create mode 100644 test/optional_test_value_access.cpp diff --git a/doc/html/boost_optional/detailed_semantics.html b/doc/html/boost_optional/detailed_semantics.html index 4a5394e..dbfe0cb 100644 --- a/doc/html/boost_optional/detailed_semantics.html +++ b/doc/html/boost_optional/detailed_semantics.html @@ -1200,6 +1200,43 @@ +

+ space +

+

+ T const& optional<T>::value() const ; +

+

+ T& + optional<T>::value(); +

+

space

diff --git a/doc/html/boost_optional/exception_safety_guarantees.html b/doc/html/boost_optional/exception_safety_guarantees.html index eb29f92..4b2b0a5 100644 --- a/doc/html/boost_optional/exception_safety_guarantees.html +++ b/doc/html/boost_optional/exception_safety_guarantees.html @@ -95,8 +95,8 @@

Unless T's constructor or assignment - throws, optional<T> does - not throw anything else on its own. A throw during assignment never changes + throws, assignments to optional<T> + do not throw anything else on its own. A throw during assignment never changes the initialization state of any optional object involved: 

optional<T> opt1(val1);
diff --git a/doc/html/boost_optional/synopsis.html b/doc/html/boost_optional/synopsis.html
index 075bfbf..0e2b20e 100644
--- a/doc/html/boost_optional/synopsis.html
+++ b/doc/html/boost_optional/synopsis.html
@@ -90,6 +90,9 @@
     T const& operator *() const ; R
     T&       operator *() ; R
 
+    T const& value() const ; R
+    T&       value() ; R
+
     T const* get_ptr() const ; R
     T*       get_ptr() ; R
 
diff --git a/doc/html/index.html b/doc/html/index.html
index 1bb9006..5c74f5b 100644
--- a/doc/html/index.html
+++ b/doc/html/index.html
@@ -92,7 +92,7 @@
 
 
 
-
+
Last revised: May 08, 2014 at 12:05:10 GMT
Last revised: May 22, 2014 at 21:28:38 GMT

 

 

 

diff --git a/doc/reference.qbk b/doc/reference.qbk
index 5cbaf6b..80c6927 100644
--- a/doc/reference.qbk
+++ b/doc/reference.qbk
@@ -74,6 +74,9 @@
 
         T const& operator *() const ; ``[link reference_optional_get __GO_TO__]``
         T&       operator *() ; ``[link reference_optional_get __GO_TO__]``
+        
+        T const& value() const ; ``[link reference_optional_value __GO_TO__]``
+        T&       value() ; ``[link reference_optional_value __GO_TO__]``
 
         T const* get_ptr() const ; ``[link reference_optional_get_ptr __GO_TO__]``
         T*       get_ptr() ; ``[link reference_optional_get_ptr __GO_TO__]``
@@ -803,6 +806,31 @@ assert ( *opt == w ) ;
 
 __SPACE__
 
+
+[#reference_optional_value]
+
+[: `T const& optional::value() const ;`]
+[: `T&       optional::value();`]
+
+* [*Returns:] A reference to the contained value, if `*this` is initialized.
+* [*Throws:] An instance of `bad_optional_access`, if `*this` is not initialized.
+* [*Example:]
+``
+T v ;
+optional o0, o1 ( v );
+assert ( o1.value() == v );
+
+try {
+  o0.value(); // throws
+  assert ( false );
+}
+catch(bad_optional_access&) {
+  asert ( true );
+}
+``
+
+__SPACE__
+
 [#reference_optional_get_value_or_value]
 
 [: `T const& optional::get_value_or( T const& default) const ;`]
diff --git a/doc/special_cases.qbk b/doc/special_cases.qbk
index adc191e..6173c16 100644
--- a/doc/special_cases.qbk
+++ b/doc/special_cases.qbk
@@ -336,7 +336,7 @@ Regarding the following assignment functions:
 
 They forward calls to the corresponding `T`'s constructors or assignments (depending on whether the optional object is initialized or not); so if both `T`'s constructor and the assignment provide strong exception safety guarantee, `optional`'s assignment also provides strong exception safety guarantee; otherwise we only get the basic guarantee. Additionally, if both involved `T`'s constructor and the assignment never throw, `optional`'s assignment also never throws.
 
-Unless `T`'s constructor or assignment throws, `optional` does not throw anything else on its own. A throw during assignment never changes the initialization state of any optional object involved:
+Unless `T`'s constructor or assignment throws, assignments to `optional` do not throw anything else on its own. A throw during assignment never changes the initialization state of any optional object involved:
 
 
     optional opt1(val1);
diff --git a/include/boost/bad_optional_access.hpp b/include/boost/bad_optional_access.hpp
new file mode 100644
index 0000000..95abf3a
--- /dev/null
+++ b/include/boost/bad_optional_access.hpp
@@ -0,0 +1,28 @@
+// Copyright (C) 2014, Andrzej Krzemienski.
+//
+// Use, modification, and distribution is subject to the Boost Software
+// License, Version 1.0. (See accompanying file LICENSE_1_0.txt or copy at
+// http://www.boost.org/LICENSE_1_0.txt)
+//
+// See http://www.boost.org/libs/optional for documentation.
+//
+// You are welcome to contact the author at:
+//  akrzemi1@gmail.com
+//
+#ifndef BOOST_BAD_OPTIONAL_ACCESS_22MAY2014_HPP
+#define BOOST_BAD_OPTIONAL_ACCESS_22MAY2014_HPP
+
+#include 
+
+namespace boost {
+
+class bad_optional_access : public std::logic_error
+{
+public:
+  explicit bad_optional_access(const std::string& what_arg) : std::logic_error(what_arg) {}
+  explicit bad_optional_access(const char* what_arg) : std::logic_error(what_arg) {}
+};
+
+} // namespace boost
+
+#endif
diff --git a/include/boost/optional/optional.hpp b/include/boost/optional/optional.hpp
index d9e8a97..b6ca7e9 100644
--- a/include/boost/optional/optional.hpp
+++ b/include/boost/optional/optional.hpp
@@ -23,7 +23,9 @@
 
 #include 
 #include 
+#include 
 #include 
+#include 
 #include 
 #include 
 #include 
@@ -935,6 +937,22 @@ class optional : public optional_detail::optional_base
     // No-throw
     reference_const_type operator *() const { return this->get() ; }
     reference_type       operator *()       { return this->get() ; }
+    
+    reference_const_type value() const
+      { 
+        if (this->is_initialized())
+          return this->get() ;
+        else
+          throw_exception(bad_optional_access("Attempted to access the value of an uninitialized optional object."));
+      }
+      
+    reference_type value()
+      { 
+        if (this->is_initialized())
+          return this->get() ;
+        else
+          throw_exception(bad_optional_access("Attempted to access the value of an uninitialized optional object."));
+      }
 
     bool operator!() const BOOST_NOEXCEPT { return !this->is_initialized() ; }
     
diff --git a/include/boost/optional/optional_fwd.hpp b/include/boost/optional/optional_fwd.hpp
index 29cee49..fb59682 100644
--- a/include/boost/optional/optional_fwd.hpp
+++ b/include/boost/optional/optional_fwd.hpp
@@ -11,11 +11,9 @@
 //
 // Revisions:
 // 10 May 2008 (added swap related forward declaration) Niels Dekker
-// 17 Apr 2014 (added noexcept) Andrzej Krzemienski 
 //
 #ifndef BOOST_OPTIONAL_OPTIONAL_FWD_FLC_19NOV2002_HPP
 #define BOOST_OPTIONAL_OPTIONAL_FWD_FLC_19NOV2002_HPP
-#include 
 
 
 namespace boost {
diff --git a/test/Jamfile.v2 b/test/Jamfile.v2
index 7218ffa..10fd597 100644
--- a/test/Jamfile.v2
+++ b/test/Jamfile.v2
@@ -23,6 +23,7 @@ import testing ;
     [ run optional_test_io.cpp ]
     [ run optional_test_move.cpp ]
     [ run optional_test_equals_none.cpp ]
+    [ run optional_test_value_access.cpp ]
     [ compile-fail optional_test_fail1.cpp ]
     [ compile-fail optional_test_fail3a.cpp ]
     [ compile-fail optional_test_fail3b.cpp ]
diff --git a/test/optional_test_value_access.cpp b/test/optional_test_value_access.cpp
new file mode 100644
index 0000000..5cff1b7
--- /dev/null
+++ b/test/optional_test_value_access.cpp
@@ -0,0 +1,107 @@
+// Copyright (C) 2014 Andrzej Krzemienski.
+//
+// Use, modification, and distribution is subject to the Boost Software
+// License, Version 1.0. (See accompanying file LICENSE_1_0.txt or copy at
+// http://www.boost.org/LICENSE_1_0.txt)
+//
+// See http://www.boost.org/lib/optional for documentation.
+//
+// You are welcome to contact the author at:
+//  akrzemi1@gmail.com
+//
+// Revisions:
+//
+#include
+#include
+#include
+
+#define BOOST_ENABLE_ASSERT_HANDLER
+
+#include "boost/bind/apply.hpp" // Included just to test proper interaction with boost::apply<> as reported by Daniel Wallin
+#include "boost/mpl/bool.hpp"
+#include "boost/mpl/bool_fwd.hpp"  // For mpl::true_ and mpl::false_
+
+#include "boost/optional/optional.hpp"
+
+#ifdef __BORLANDC__
+#pragma hdrstop
+#endif
+
+#include "boost/none.hpp"
+
+#include "boost/test/minimal.hpp"
+
+#include "optional_test_common.cpp"
+
+struct IntWrapper
+{
+  int _i;
+  IntWrapper(int i) : _i(i) {}
+  bool operator==(IntWrapper const& rhs) const { return _i == rhs._i; }
+};
+
+template 
+void test_function_value_for()
+{
+  optional o0;
+  optional o1(1);
+  const optional oC(2);
+  
+  try
+  {
+    T& v = o1.value();
+    BOOST_CHECK(v == 1);
+  }
+  catch(...)
+  {
+    BOOST_CHECK(false);
+  }
+  
+  try
+  {
+    T const& v = oC.value();
+    BOOST_CHECK(v == 2);
+  }
+  catch(...)
+  {
+    BOOST_CHECK(false);
+  }
+  
+  try
+  {
+    T& v = o0.value();
+    BOOST_CHECK(false);
+    unused_variable(v);
+  }
+  catch(boost::bad_optional_access const&)
+  {
+  }
+  catch(...)
+  {
+    BOOST_CHECK(false);
+  }
+}
+
+void test_function_value()
+{
+    test_function_value_for();
+    test_function_value_for();
+    test_function_value_for();
+}
+
+int test_main( int, char* [] )
+{
+  try
+  {
+    test_function_value();
+
+  }
+  catch ( ... )
+  {
+    BOOST_ERROR("Unexpected Exception caught!");
+  }
+
+  return 0;
+}
+
+