fixup: add minimal filesystem implementation

Implement the minimum possible surface of std::experimental::filesystem
in terms of POSIX APIs so that we can compile under mingw

Makefile.am

@@ -344,6 +344,13 @@ if HAVE_CAPTURESTACKBACKTRACE
 __BACKTRACE_FILES += backtrace_stackwalk.cpp backtrace_win32.cpp
 endif
 
+if !HAVE_STD_EXPERIMENTAL_FILESYSTEM
+AM_CXXFLAGS += -isystem ${top_srcdir}/fixup
+UTIL_FILES += \
+	fixup/experimental/filesystem.hpp \
+	fixup/experimental/filesystem.cpp
+endif
+
 BACKTRACE_FILES=$(firstword $(__BACKTRACE_FILES) backtrace_null.cpp)
 
 

configure.ac

@@ -52,6 +52,9 @@ AS_IF([test "x${host_os}" != "xmingw32"],[
 
 AC_FUNC_MMAP
 
+AC_CHECK_HEADERS([experimental/filesystem])
+AM_CONDITIONAL([HAVE_STD_EXPERIMENTAL_FILESYSTEM], [test "x$ac_cv_header_experimental_filesystem" == "xyes"])
+
 AC_SEARCH_LIBS([backtrace], [execinfo])
 AC_CHECK_FUNC([backtrace])
 AM_CONDITIONAL([HAVE_EXECINFO], [test "x$ac_cv_func_backtrace" == "xyes"])

fixup/experimental/filesystem

@@ -0,0 +1 @@
+#include "./filesystem.hpp"

fixup/experimental/filesystem.cpp

@@ -0,0 +1,121 @@
+/*
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ *
+ * Copyright 2016 Danny Robson <danny@nerdcruft.net>
+ */
+
+#include "./filesystem.hpp"
+
+#include "../../except.hpp"
+
+#include <algorithm>
+#include <sys/types.h>
+#include <sys/stat.h>
+#include <unistd.h>
+
+namespace ns = std::experimental::filesystem;
+
+
+///////////////////////////////////////////////////////////////////////////////
+ns::path::path ()
+{ ; }
+
+
+//-----------------------------------------------------------------------------
+ns::path::path (const path &p):
+    m_path (p.m_path)
+{ ; }
+
+
+///////////////////////////////////////////////////////////////////////////////
+std::string
+ns::path::string (void) const
+{
+    return m_path;
+}
+
+
+///////////////////////////////////////////////////////////////////////////////
+const ns::path::string_type&
+ns::path::native (void) const
+{
+    return m_path;
+}
+
+
+//-----------------------------------------------------------------------------
+const ns::path::value_type*
+ns::path::c_str (void) const
+{
+    return m_path.c_str ();
+}
+
+
+///////////////////////////////////////////////////////////////////////////////
+ns::path
+ns::path::filename (void) const
+{
+    auto slash = m_path.find_last_of (preferred_separator);
+    if (slash == decltype(m_path)::npos)
+        return m_path;
+    return ns::path (m_path.cbegin () + slash, m_path.cend ());
+}
+
+//-----------------------------------------------------------------------------
+ns::path
+ns::path::stem (void) const
+{
+    auto name = filename ();
+
+    auto first = name.m_path.cbegin ();
+    auto last  = std::find_if (first, name.m_path.cend (), [] (auto c) { return c == '.'; });
+    return path (first, last);
+}
+
+
+///////////////////////////////////////////////////////////////////////////////
+ns::path
+ns::operator/ (const ns::path &a, const ns::path &b)
+{
+    return ns::path (a) /= b;
+}
+
+
+//-----------------------------------------------------------------------------
+ns::path&
+ns::path::operator/= (const path &rhs)
+{
+    m_path += preferred_separator + rhs.m_path;
+    return *this;
+}
+
+
+///////////////////////////////////////////////////////////////////////////////
+bool
+ns::operator== (const path &a, const path &b)
+{
+    return a == b;
+}
+
+
+///////////////////////////////////////////////////////////////////////////////
+bool
+ns::is_directory (const path &p)
+{
+    struct stat buf;
+
+    if (stat (p.c_str (), &buf))
+        ::util::errno_error::throw_code ();
+
+    return S_ISDIR (buf.st_mode);
+}

fixup/experimental/filesystem.hpp

@@ -0,0 +1,74 @@
+/*
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ *
+ * Copyright 2016 Danny Robson <danny@nerdcruft.net>
+ */
+
+#ifndef CRUFT_UTIL_FIXUP_EXPERIMENTAL_FILESYSTEM_HPP
+#define CRUFT_UTIL_FIXUP_EXPERIMENTAL_FILESYSTEM_HPP
+
+#include <string>
+
+///////////////////////////////////////////////////////////////////////////////
+namespace std::experimental::filesystem {
+    class path {
+    public:
+        using value_type = char;
+        using string_type = std::basic_string<value_type>;
+        
+        static constexpr value_type preferred_separator = '/';
+
+        path ();
+        path (const path&);
+
+        template <class Source>
+        path (const Source &s):
+            m_path (s)
+        { ; }
+
+        template <class InputT>
+        path (InputT first, InputT last):
+            m_path (first, last)
+        { ; }
+
+        std::string string (void) const;
+
+        const string_type& native (void) const;
+        const value_type* c_str (void) const;
+
+        path filename (void) const;
+        path stem (void) const;
+
+        path& operator/= (const path&);
+
+    private:
+        string_type m_path;
+    };
+
+    path operator/ (const path&, const path&);
+
+    bool operator== (const path&, const path&);
+
+    //bool is_directory (file_status);
+    bool is_directory (const path&);
+    //bool is_directory (const path&, error_code&);
+
+    template <class CharT, class Traits>
+    std::basic_ostream<CharT,Traits>&
+    operator<< (std::basic_ostream<CharT,Traits> &os, const path &p)
+    { return os << p.native (); }
+}
+
+
+#endif
+