From 8a2b9caf6ee2e69df7e9e6d00faf3250882e3e10 Mon Sep 17 00:00:00 2001
From: Emil Dotchevski <emildotchevski@gmail.com>
Date: Sun, 20 Jan 2019 02:44:47 -0800
Subject: [PATCH] sending error_id through std::error_code

---
 .vscode/tasks.json                            | 18 +++++
 example/print_file_result.cpp                 |  1 +
 example/print_half.cpp                        |  1 +
 include/boost/leaf/error.hpp                  |  4 +
 include/boost/leaf/error_code.hpp             | 80 +++++++++++++++++++
 include/boost/leaf/handle.hpp                 | 45 ++++++++---
 include/boost/leaf/result.hpp                 | 12 ++-
 meson.build                                   |  2 +
 test/Jamfile.v2                               |  2 +
 test/defer_basic_test.cpp                     |  1 +
 test/defer_nested_error_result_test.cpp       |  1 +
 test/defer_nested_new_error_result_test.cpp   |  1 +
 test/defer_nested_success_result_test.cpp     |  1 +
 test/handle_all_error_code_test.cpp           | 70 ++++++++++++++++
 test/handle_all_test.cpp                      |  1 +
 test/handle_some_basic_test.cpp               |  1 +
 test/handle_some_error_code_test.cpp          | 56 +++++++++++++
 test/handle_some_test.cpp                     |  1 +
 test/preload_basic_test.cpp                   |  1 +
 test/preload_nested_error_result_test.cpp     |  1 +
 test/preload_nested_new_error_result_test.cpp |  1 +
 test/preload_nested_success_result_test.cpp   |  1 +
 22 files changed, 287 insertions(+), 15 deletions(-)
 create mode 100644 include/boost/leaf/error_code.hpp
 create mode 100644 test/handle_all_error_code_test.cpp
 create mode 100644 test/handle_some_error_code_test.cpp

diff --git a/.vscode/tasks.json b/.vscode/tasks.json
index 5e23d46..cd25e46 100644
--- a/.vscode/tasks.json
+++ b/.vscode/tasks.json
@@ -158,6 +158,15 @@
 				"command": "${workspaceRoot}/.vscode/msvc.bat && cd ${workspaceRoot}/bld/debug && meson test function_traits_test"
 			}
 		},
+		{
+			"label": "handle_all_error_code_test",
+			"type": "shell",
+			"command": "cd ${workspaceRoot}/bld/debug && meson test handle_all_error_code_test",
+			"problemMatcher": { "base": "$gcc", "fileLocation": ["relative","${workspaceRoot}/bld/debug"] },
+			"windows": {
+				"command": "${workspaceRoot}/.vscode/msvc.bat && cd ${workspaceRoot}/bld/debug && meson test handle_all_error_code_test"
+			}
+		},
 		{
 			"label": "handle_all_test",
 			"type": "shell",
@@ -176,6 +185,15 @@
 				"command": "${workspaceRoot}/.vscode/msvc.bat && cd ${workspaceRoot}/bld/debug && meson test handle_some_basic_test"
 			}
 		},
+		{
+			"label": "handle_some_error_code_test",
+			"type": "shell",
+			"command": "cd ${workspaceRoot}/bld/debug && meson test handle_some_error_code_test",
+			"problemMatcher": { "base": "$gcc", "fileLocation": ["relative","${workspaceRoot}/bld/debug"] },
+			"windows": {
+				"command": "${workspaceRoot}/.vscode/msvc.bat && cd ${workspaceRoot}/bld/debug && meson test handle_some_error_code_test"
+			}
+		},
 		{
 			"label": "handle_some_test",
 			"type": "shell",
diff --git a/example/print_file_result.cpp b/example/print_file_result.cpp
index 0d56634..220cf61 100644
--- a/example/print_file_result.cpp
+++ b/example/print_file_result.cpp
@@ -8,6 +8,7 @@
 // using LEAF to handle errors. It does not use exception handling.
 
 #include <boost/leaf/handle.hpp>
+#include <boost/leaf/result.hpp>
 #include <boost/leaf/preload.hpp>
 #include <iostream>
 #include <memory>
diff --git a/example/print_half.cpp b/example/print_half.cpp
index 7d122d4..32af03e 100644
--- a/example/print_half.cpp
+++ b/example/print_half.cpp
@@ -8,6 +8,7 @@
 // https://github.com/ned14/outcome/blob/master/doc/src/snippets/using_result.cpp
 
 #include <boost/leaf/handle.hpp>
+#include <boost/leaf/result.hpp>
 #include <algorithm>
 #include <ctype.h>
 #include <string>
diff --git a/include/boost/leaf/error.hpp b/include/boost/leaf/error.hpp
index 202e511..d9f7be2 100644
--- a/include/boost/leaf/error.hpp
+++ b/include/boost/leaf/error.hpp
@@ -26,6 +26,7 @@ namespace boost { namespace leaf {
 
 	error_id next_error() noexcept;
 	error_id last_error() noexcept;
+	error_id get_error_id( std::error_code const & ) noexcept;
 
 	class error_id
 	{
@@ -33,6 +34,7 @@ namespace boost { namespace leaf {
 		friend error_id new_error( E && ... ) noexcept;
 		friend error_id leaf::next_error() noexcept;
 		friend error_id leaf::last_error() noexcept;
+		friend error_id get_error_id( std::error_code const & ) noexcept;
 
 		unsigned id_;
 
@@ -112,6 +114,8 @@ namespace boost { namespace leaf {
 
 		template <class... E>
 		error_id propagate( E && ... ) const noexcept;
+
+		std::error_code to_error_code() const noexcept;
 	};
 
 	template <class... E>
diff --git a/include/boost/leaf/error_code.hpp b/include/boost/leaf/error_code.hpp
new file mode 100644
index 0000000..0826211
--- /dev/null
+++ b/include/boost/leaf/error_code.hpp
@@ -0,0 +1,80 @@
+#ifndef BOOST_LEAF_B146ADCE1C7A11E9A455E6F387D1CC0E
+#define BOOST_LEAF_B146ADCE1C7A11E9A455E6F387D1CC0E
+
+// Copyright (c) 2018 Emil Dotchevski
+// Copyright (c) 2018 Second Spectrum, Inc.
+
+// Distributed under 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)
+
+#include <boost/leaf/error.hpp>
+
+namespace boost { namespace leaf {
+
+	class error_category: public std::error_category
+	{
+		bool equivalent( int,  std::error_condition const & ) const noexcept
+		{
+			return false;
+		}
+
+		bool equivalent( std::error_code const &, int ) const noexcept
+		{
+			return false;
+		}
+
+		char const * name() const noexcept
+		{
+			return "LEAF error, use with leaf::handle_some or leaf::handle_all.";
+		}
+
+		std::string message( int condition ) const
+		{
+			return name();
+		}
+	};
+
+	namespace leaf_detail
+	{
+		inline error_category const & get_error_category() noexcept
+		{
+			static error_category cat;
+			return cat;
+		}
+
+		inline error_category const & get_error_category0() noexcept
+		{
+			static error_category cat;
+			return cat;
+		}
+	}
+
+	inline std::error_code error_id::to_error_code() const noexcept
+	{
+		return id_ ?
+			std::error_code( int(id_), leaf_detail::get_error_category() ) :
+			std::error_code( -1, leaf_detail::get_error_category0() );
+	}
+
+	inline error_id get_error_id( std::error_code const & ec ) noexcept
+	{
+		std::error_category const & cat =  ec.category();
+		if( &cat==&leaf_detail::get_error_category() )
+			return error_id(ec.value());
+		else if( &cat==&leaf_detail::get_error_category0() )
+		{
+			assert(ec.value()==-1);
+			return error_id(0);
+		}
+		else
+			return leaf::next_error();
+	}
+
+	inline bool succeeded( std::error_code const & ec )
+	{
+		return !ec;
+	}
+
+} }
+
+#endif
diff --git a/include/boost/leaf/handle.hpp b/include/boost/leaf/handle.hpp
index 6722d70..663d9e7 100644
--- a/include/boost/leaf/handle.hpp
+++ b/include/boost/leaf/handle.hpp
@@ -7,25 +7,40 @@
 // Distributed under 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)
 
-#include <boost/leaf/result.hpp>
 #include <boost/leaf/detail/static_store.hpp>
 
 namespace boost { namespace leaf {
 
+	template <class T>
+	class result;
+
+	template <class T>
+	bool succeeded( result<T> const & r )
+	{
+		return bool(r);
+	}
+
 	template <class TryBlock, class... Handler>
 	typename std::remove_reference<decltype(std::declval<TryBlock>()().value())>::type handle_all( TryBlock && try_block, Handler && ... handler )
 	{
 		using namespace leaf_detail;
 		typename deduce_static_store<typename handler_args_set<Handler...>::type>::type ss;
 		ss.set_reset(true);
-		if( auto r = std::forward<TryBlock>(try_block)() )
-			return *r;
+		auto r = std::forward<TryBlock>(try_block)();
+		if( succeeded(r) )
+			return r.value();
 		else
-			return ss.handle_error(error_info(r.error()), std::forward<Handler>(handler)...);
+			return ss.handle_error(error_info(get_error_id(r)), std::forward<Handler>(handler)...);
 	}
 
 	namespace leaf_detail
 	{
+		template <class... A>
+		struct dependent_type_result_void
+		{
+			using type = result<void>;
+		};
+
 		template <class R, class F, class = typename function_traits<F>::mp_args>
 		struct handler_wrapper;
 
@@ -51,7 +66,7 @@ namespace boost { namespace leaf {
 				f_(std::forward<F>(f))
 			{
 			}
-			result<void> operator()( A... a ) const
+			typename dependent_type_result_void<A...>::type operator()( A... a ) const
 			{
 				f_(a...);
 				return { };
@@ -65,18 +80,24 @@ namespace boost { namespace leaf {
 		using namespace leaf_detail;
 		using R = typename function_traits<TryBlock>::return_type;
 		typename deduce_static_store<typename handler_args_set<Handler...>::type>::type ss;
-		if( auto r = std::forward<TryBlock>(try_block)() )
+
+		auto r = std::forward<TryBlock>(try_block)();
+		if( succeeded(r) )
 		{
 			ss.set_reset(true);
 			return r;
 		}
-		else if( auto rr = ss.handle_error(error_info(r.error()), handler_wrapper<R,Handler>(std::forward<Handler>(handler))..., [&r] { return r; } ) )
-		{
-			ss.set_reset(true);
-			return rr;
-		}
 		else
-			return rr;
+		{
+			auto rr = ss.handle_error(error_info(get_error_id(r)), handler_wrapper<R,Handler>(std::forward<Handler>(handler))..., [&r] { return r; } );
+			if( succeeded(rr) )
+			{
+				ss.set_reset(true);
+				return rr;
+			}
+			else
+				return rr;
+		}
 	}
 
 } }
diff --git a/include/boost/leaf/result.hpp b/include/boost/leaf/result.hpp
index 99882b4..6396746 100644
--- a/include/boost/leaf/result.hpp
+++ b/include/boost/leaf/result.hpp
@@ -35,9 +35,9 @@ namespace boost { namespace leaf {
 			dynamic_store_ptr cap_;
 		};
 
-		leaf_detail::result_variant which_;
+		mutable leaf_detail::result_variant which_;
 
-		void destroy() noexcept
+		void destroy() const noexcept
 		{
 			switch( which_ )
 			{
@@ -219,7 +219,7 @@ namespace boost { namespace leaf {
 		}
 
 		template <class... E>
-		error_id error( E && ... e ) noexcept
+		error_id error( E && ... e ) const noexcept
 		{
 			switch( which_ )
 			{
@@ -286,6 +286,12 @@ namespace boost { namespace leaf {
 		using base::error;
 	};
 
+	template <class T>
+	error_id get_error_id( result<T> const & r )
+	{
+		return r.error();
+	}
+
 } }
 
 #endif
diff --git a/meson.build b/meson.build
index bf0091a..adf64c4 100644
--- a/meson.build
+++ b/meson.build
@@ -52,8 +52,10 @@ tests = [
 	'defer_nested_success_result_test',
 	'diagnostic_info_test',
 	'function_traits_test',
+	'handle_all_error_code_test',
 	'handle_all_test',
 	'handle_some_basic_test',
+	'handle_some_error_code_test',
 	'handle_some_test',
 	'is_error_type_test',
 	'optional_test',
diff --git a/test/Jamfile.v2 b/test/Jamfile.v2
index 86df7df..004457b 100644
--- a/test/Jamfile.v2
+++ b/test/Jamfile.v2
@@ -45,8 +45,10 @@ run defer_nested_success_exception_test.cpp ;
 run defer_nested_success_result_test.cpp ;
 run diagnostic_info_test.cpp ;
 run function_traits_test.cpp ;
+run handle_all_error_code_test.cpp ;
 run handle_all_test.cpp ;
 run handle_some_basic_test.cpp ;
+run handle_some_error_code_test.cpp ;
 run handle_some_test.cpp ;
 run is_error_type_test.cpp ;
 run optional_test.cpp ;
diff --git a/test/defer_basic_test.cpp b/test/defer_basic_test.cpp
index 4d1e839..653257e 100644
--- a/test/defer_basic_test.cpp
+++ b/test/defer_basic_test.cpp
@@ -6,6 +6,7 @@
 
 #include <boost/leaf/preload.hpp>
 #include <boost/leaf/handle.hpp>
+#include <boost/leaf/result.hpp>
 #include "boost/core/lightweight_test.hpp"
 
 namespace leaf = boost::leaf;
diff --git a/test/defer_nested_error_result_test.cpp b/test/defer_nested_error_result_test.cpp
index 7589d01..e47ee33 100644
--- a/test/defer_nested_error_result_test.cpp
+++ b/test/defer_nested_error_result_test.cpp
@@ -6,6 +6,7 @@
 
 #include <boost/leaf/preload.hpp>
 #include <boost/leaf/handle.hpp>
+#include <boost/leaf/result.hpp>
 #include "boost/core/lightweight_test.hpp"
 
 namespace leaf = boost::leaf;
diff --git a/test/defer_nested_new_error_result_test.cpp b/test/defer_nested_new_error_result_test.cpp
index 6465426..6a307c4 100644
--- a/test/defer_nested_new_error_result_test.cpp
+++ b/test/defer_nested_new_error_result_test.cpp
@@ -6,6 +6,7 @@
 
 #include <boost/leaf/preload.hpp>
 #include <boost/leaf/handle.hpp>
+#include <boost/leaf/result.hpp>
 #include "boost/core/lightweight_test.hpp"
 
 namespace leaf = boost::leaf;
diff --git a/test/defer_nested_success_result_test.cpp b/test/defer_nested_success_result_test.cpp
index ed35d04..462922f 100644
--- a/test/defer_nested_success_result_test.cpp
+++ b/test/defer_nested_success_result_test.cpp
@@ -6,6 +6,7 @@
 
 #include <boost/leaf/preload.hpp>
 #include <boost/leaf/handle.hpp>
+#include <boost/leaf/result.hpp>
 #include "boost/core/lightweight_test.hpp"
 
 namespace leaf = boost::leaf;
diff --git a/test/handle_all_error_code_test.cpp b/test/handle_all_error_code_test.cpp
new file mode 100644
index 0000000..fb5ef90
--- /dev/null
+++ b/test/handle_all_error_code_test.cpp
@@ -0,0 +1,70 @@
+// Copyright (c) 2018 Emil Dotchevski
+// Copyright (c) 2018 Second Spectrum, Inc.
+
+// Distributed under 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)
+
+#include <boost/leaf/error_code.hpp>
+#include <boost/leaf/handle.hpp>
+#include "boost/core/lightweight_test.hpp"
+#include <cstring>
+
+namespace leaf = boost::leaf;
+
+template <int> struct info { int value; };
+
+int main()
+{
+	{
+		int r = leaf::handle_all(
+			[ ]
+			{
+				return std::error_code();
+			},
+			[ ]
+			{
+				return ENOENT;
+			} );
+		BOOST_TEST(!r);
+	}
+	{
+		int r = leaf::handle_all(
+			[&]
+			{
+				std::error_code ec = leaf::new_error(info<1>{1}).to_error_code();
+				BOOST_TEST(ec);
+				BOOST_TEST(ec.message()=="LEAF error, use with leaf::handle_some or leaf::handle_all.");
+				BOOST_TEST(!std::strcmp(ec.category().name(),"LEAF error, use with leaf::handle_some or leaf::handle_all."));
+				return ec;
+			},
+			[ ]( info<1> const & x )
+			{
+				BOOST_TEST(x.value==1);
+				return 1;
+			},
+			[ ]
+			{
+				return 2;
+			} );
+		BOOST_TEST(r==1);
+	}
+	{
+		int r = leaf::handle_all(
+			[&]
+			{
+				return leaf::new_error(info<2>{2},std::error_code(ENOENT,std::system_category())).to_error_code();
+			},
+			[ ]( info<2> const & x, std::error_code const & ec )
+			{
+				BOOST_TEST(x.value==2);
+				BOOST_TEST(ec==std::error_code(ENOENT,std::system_category()));
+				return 1;
+			},
+			[ ]
+			{
+				return 2;
+			} );
+		BOOST_TEST(r==1);
+	}
+	return boost::report_errors();
+}
diff --git a/test/handle_all_test.cpp b/test/handle_all_test.cpp
index aa0d3a0..a6d9a91 100644
--- a/test/handle_all_test.cpp
+++ b/test/handle_all_test.cpp
@@ -5,6 +5,7 @@
 // file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
 
 #include <boost/leaf/handle.hpp>
+#include <boost/leaf/result.hpp>
 #include "boost/core/lightweight_test.hpp"
 
 namespace leaf = boost::leaf;
diff --git a/test/handle_some_basic_test.cpp b/test/handle_some_basic_test.cpp
index f3a3439..9784eef 100644
--- a/test/handle_some_basic_test.cpp
+++ b/test/handle_some_basic_test.cpp
@@ -5,6 +5,7 @@
 // file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
 
 #include <boost/leaf/handle.hpp>
+#include <boost/leaf/result.hpp>
 #include "boost/core/lightweight_test.hpp"
 
 namespace leaf = boost::leaf;
diff --git a/test/handle_some_error_code_test.cpp b/test/handle_some_error_code_test.cpp
new file mode 100644
index 0000000..ef0d9cd
--- /dev/null
+++ b/test/handle_some_error_code_test.cpp
@@ -0,0 +1,56 @@
+// Copyright (c) 2018 Emil Dotchevski
+// Copyright (c) 2018 Second Spectrum, Inc.
+
+// Distributed under 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)
+
+#include <boost/leaf/error_code.hpp>
+#include <boost/leaf/handle.hpp>
+#include "boost/core/lightweight_test.hpp"
+#include <cstring>
+
+namespace leaf = boost::leaf;
+
+template <int> struct info { int value; };
+
+int main()
+{
+	{
+		int what=0;
+		std::error_code r = leaf::handle_some(
+			[&]
+			{
+				std::error_code ec = leaf::new_error(info<1>{1}).to_error_code();
+				BOOST_TEST(ec);
+				BOOST_TEST(ec.message()=="LEAF error, use with leaf::handle_some or leaf::handle_all.");
+				BOOST_TEST(!std::strcmp(ec.category().name(),"LEAF error, use with leaf::handle_some or leaf::handle_all."));
+				return ec;
+			},
+			[&]( info<1> const & x )
+			{
+				what = 1;
+				BOOST_TEST(x.value==1);
+				return std::error_code(ENOENT,std::system_category());
+			} );
+		BOOST_TEST(r==std::error_code(ENOENT,std::system_category()));
+		BOOST_TEST(what==1);
+	}
+	{
+		int what=0;
+		std::error_code ec = leaf::handle_some(
+			[&]
+			{
+				return leaf::new_error(info<2>{2},std::error_code(ENOENT,std::system_category())).to_error_code();
+			},
+			[&]( info<2> const & x, std::error_code const & ec )
+			{
+				what = 2;
+				BOOST_TEST(x.value==2);
+				BOOST_TEST(ec==std::error_code(ENOENT,std::system_category()));
+				return ec;
+			} );
+		BOOST_TEST(ec==std::error_code(ENOENT,std::system_category()));
+		BOOST_TEST(what==2);
+	}
+	return boost::report_errors();
+}
diff --git a/test/handle_some_test.cpp b/test/handle_some_test.cpp
index 3ccea70..51c57a5 100644
--- a/test/handle_some_test.cpp
+++ b/test/handle_some_test.cpp
@@ -5,6 +5,7 @@
 // file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
 
 #include <boost/leaf/handle.hpp>
+#include <boost/leaf/result.hpp>
 #include "boost/core/lightweight_test.hpp"
 
 namespace leaf = boost::leaf;
diff --git a/test/preload_basic_test.cpp b/test/preload_basic_test.cpp
index f31e2c3..95c6551 100644
--- a/test/preload_basic_test.cpp
+++ b/test/preload_basic_test.cpp
@@ -6,6 +6,7 @@
 
 #include <boost/leaf/preload.hpp>
 #include <boost/leaf/handle.hpp>
+#include <boost/leaf/result.hpp>
 #include "boost/core/lightweight_test.hpp"
 
 namespace leaf = boost::leaf;
diff --git a/test/preload_nested_error_result_test.cpp b/test/preload_nested_error_result_test.cpp
index 3f229c3..6e7fbb3 100644
--- a/test/preload_nested_error_result_test.cpp
+++ b/test/preload_nested_error_result_test.cpp
@@ -6,6 +6,7 @@
 
 #include <boost/leaf/preload.hpp>
 #include <boost/leaf/handle.hpp>
+#include <boost/leaf/result.hpp>
 #include "boost/core/lightweight_test.hpp"
 
 namespace leaf = boost::leaf;
diff --git a/test/preload_nested_new_error_result_test.cpp b/test/preload_nested_new_error_result_test.cpp
index 97e8235..da786e5 100644
--- a/test/preload_nested_new_error_result_test.cpp
+++ b/test/preload_nested_new_error_result_test.cpp
@@ -6,6 +6,7 @@
 
 #include <boost/leaf/preload.hpp>
 #include <boost/leaf/handle.hpp>
+#include <boost/leaf/result.hpp>
 #include "boost/core/lightweight_test.hpp"
 
 namespace leaf = boost::leaf;
diff --git a/test/preload_nested_success_result_test.cpp b/test/preload_nested_success_result_test.cpp
index 5a64739..80fa5d6 100644
--- a/test/preload_nested_success_result_test.cpp
+++ b/test/preload_nested_success_result_test.cpp
@@ -6,6 +6,7 @@
 
 #include <boost/leaf/preload.hpp>
 #include <boost/leaf/handle.hpp>
+#include <boost/leaf/result.hpp>
 #include "boost/core/lightweight_test.hpp"
 
 namespace leaf = boost::leaf;