Add a scoped CWD restorer, and set method

io.cpp

@@ -131,6 +131,24 @@ indenter::~indenter ()
         m_owner->rdbuf (m_dest);
 }
 
+//----------------------------------------------------------------------------
+scoped_cwd::scoped_cwd ():
+    m_original (getcwd (nullptr, 0))
+{
+    if (!m_original)
+        throw errno_error ();
+}
+
+
+scoped_cwd::~scoped_cwd () {
+    set_cwd (m_original.data ());
+}
+
+
+void
+util::set_cwd (const boost::filesystem::path &path) {
+    chdir (path.string ().c_str ());
+}
 
 //----------------------------------------------------------------------------
 #if defined(HAVE_MMAP)
@@ -189,4 +207,3 @@ mapped_file::data (void) const {
 }
 #endif
 
-

io.hpp

@@ -76,6 +76,18 @@ namespace util {
     };
 
     
+    class scoped_cwd {
+        public:
+            scoped_cwd ();
+            ~scoped_cwd ();
+
+        protected:
+            scoped_malloc<char> m_original;
+    };
+
+
+    void set_cwd (const boost::filesystem::path &);
+
 
 #if defined(HAVE_MMAP)
     /// Wraps a mechanism to map a file into memory. Read only.