From 3f2323dae243d7654d3319fe7f53b87062b0d62e Mon Sep 17 00:00:00 2001
From: Karen Arutyunov <karen@codesynthesis.com>
Date: Fri, 17 Feb 2017 09:27:02 +0000
Subject: Fix cpfile() to throw system_error only

---
 butl/fdstream.cxx       |  9 ++++----
 butl/filesystem.cxx     | 58 ++++++++++++++++++++++++++++++++++++++++++-------
 tests/cpfile/driver.cxx |  4 ++--
 3 files changed, 56 insertions(+), 15 deletions(-)

diff --git a/butl/fdstream.cxx b/butl/fdstream.cxx
index e28eb0f..bdbfa08 100644
--- a/butl/fdstream.cxx
+++ b/butl/fdstream.cxx
@@ -39,8 +39,8 @@ namespace butl
   // throw_ios_failure
   //
   template <bool v>
-  static inline void
-  throw_ios_failure (error_code e, typename enable_if<v, const char*>::type m)
+  static inline typename enable_if<v>::type
+  throw_ios_failure (error_code e, const char* m)
   {
     // The idea here is to make an error code to be saved into failure
     // exception and to make a string returned by what() to contain the error
@@ -57,9 +57,8 @@ namespace butl
   }
 
   template <bool v>
-  static inline void
-  throw_ios_failure (error_code e,
-                     typename enable_if<!v, const char*>::type m)
+  static inline typename enable_if<!v>::type
+  throw_ios_failure (error_code e, const char* m)
   {
     throw ios_base::failure (m != nullptr ? m : e.message ().c_str ());
   }
diff --git a/butl/filesystem.cxx b/butl/filesystem.cxx
index 1553324..e792bef 100644
--- a/butl/filesystem.cxx
+++ b/butl/filesystem.cxx
@@ -288,10 +288,18 @@ namespace butl
   }
 #endif
 
-  void
-  cpfile (const path& from, const path& to, cpflags fl)
+  // For I/O operations cpfile() can throw ios_base::failure exception that is
+  // not derived from system_error for old versions of g++ (as of 4.9). From
+  // the other hand cpfile() must throw system_error only. Let's catch
+  // ios_base::failure and rethrow as system_error in such a case.
+  //
+  template <bool v>
+  static inline typename enable_if<v>::type
+  cpfile (const path& from, const path& to,
+          cpflags fl,
+          permissions perm,
+          auto_rmfile& rm)
   {
-    permissions perm (path_permissions (from));
     ifdstream ifs (from, fdopen_mode::binary);
 
     fdopen_mode om (fdopen_mode::out      |
@@ -302,11 +310,6 @@ namespace butl
     if ((fl & cpflags::overwrite_content) != cpflags::overwrite_content)
       om |= fdopen_mode::exclusive;
 
-    // Create prior to the output file stream creation so that the file is
-    // removed after it is closed.
-    //
-    auto_rmfile rm;
-
     ofdstream ofs (fdopen (to, om, perm));
 
     rm = auto_rmfile (to);
@@ -321,6 +324,45 @@ namespace butl
 
     ifs.close (); // Throws ios::failure on failure.
     ofs.close (); // Throws ios::failure on flush/close failure.
+  }
+
+  template <bool v>
+  static inline typename enable_if<!v>::type
+  cpfile (const path& from, const path& to,
+          cpflags fl,
+          permissions perm,
+          auto_rmfile& rm)
+  {
+    try
+    {
+      cpfile<true> (from, to, fl, perm, rm);
+    }
+    catch (const ios_base::failure& e)
+    {
+      // While we try to preserve the original error information, we can not
+      // make the description to be exactly the same, for example
+      //
+      // Is a directory
+      //
+      // becomes
+      //
+      // Is a directory: Input/output error
+      //
+      // Note that our custom operator<<(ostream, exception) doesn't strip this
+      // suffix. This is a temporary code after all.
+      //
+      throw system_error (EIO, system_category (), e.what ());
+    }
+  }
+
+  void
+  cpfile (const path& from, const path& to, cpflags fl)
+  {
+    permissions perm (path_permissions (from));
+    auto_rmfile rm;
+
+    cpfile<is_base_of<system_error, ios_base::failure>::value> (
+      from, to, fl, perm, rm);
 
     if ((fl & cpflags::overwrite_permissions) ==
         cpflags::overwrite_permissions)
diff --git a/tests/cpfile/driver.cxx b/tests/cpfile/driver.cxx
index 7276405..732b364 100644
--- a/tests/cpfile/driver.cxx
+++ b/tests/cpfile/driver.cxx
@@ -101,7 +101,7 @@ main ()
     cpfile (from, to, cpflags::none);
     assert (false);
   }
-  catch (const ios::failure&)
+  catch (const system_error&)
   {
   }
 
@@ -174,7 +174,7 @@ main ()
     cpfile (from, tslink, cpflags::none);
     assert (false);
   }
-  catch (const ios::failure&)
+  catch (const system_error&)
   {
   }
 
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