Add result extension for translating io errors to exit codes

lib/core/libimagerror/src/io.rs

@@ -0,0 +1,65 @@
+//
+// imag - the personal information management suite for the commandline
+// Copyright (C) 2015-2018 the imag contributors
+//
+// This library is free software; you can redistribute it and/or
+// modify it under the terms of the GNU Lesser General Public
+// License as published by the Free Software Foundation; version
+// 2.1 of the License.
+//
+// This library is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+// Lesser General Public License for more details.
+//
+// You should have received a copy of the GNU Lesser General Public
+// License along with this library; if not, write to the Free Software
+// Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301  USA
+//
+
+use std::io::ErrorKind;
+
+use trace::MapErrTrace;
+
+pub enum Settings {
+    Ignore(ErrorKind),
+    IgnoreAny(Vec<ErrorKind>),
+}
+
+pub trait ToExitCode : MapErrTrace {
+    fn to_exit_code(self) -> i32;
+    fn to_exit_code_with(self, Settings) -> i32;
+}
+
+impl<T> ToExitCode for Result<T, ::std::io::Error> {
+
+    /// Returns an exit code of 0 if the error was a broken pipe, else 1
+    fn to_exit_code(self) -> {
+        self.to_exit_code_with(Settings::ErrorOn(ErrorKind::BrokenPipe))
+    }
+
+    /// Returns an exit code depending on the settings
+    ///
+    /// Via the settings, errors can be ignores (translates to exit code zero). All other errors
+    /// are translated into exit code 1
+    ///
+    fn to_exit_code_with(self, settings: Settings) -> i32 {
+        if let Err(e) = self {
+            match settings {
+                Ignore(kind) => if e.kind() == kind {
+                    0
+                } else {
+                    1
+                },
+                IgnoreAny(v) => if v.iter().any(|e| e == e.kind()) {
+                    0
+                } else {
+                    1
+                },
+            }
+        } else {
+            0
+        }
+    }
+
+}

lib/core/libimagerror/src/lib.rs

@@ -37,6 +37,7 @@
 extern crate ansi_term;
 extern crate error_chain;
 
+pub mod io;
 pub mod trace;
 pub mod iter;
 pub mod str;