Move Error, helpers and macros into a util module.

src/util/helpers.rs

@@ -0,0 +1,53 @@
+// Copyright (c) 2017 Emmanuel Gil Peyrot <linkmauve@linkmauve.fr>
+//
+// This Source Code Form is subject to the terms of the Mozilla Public
+// License, v. 2.0. If a copy of the MPL was not distributed with this
+// file, You can obtain one at http://mozilla.org/MPL/2.0/.
+
+use crate::util::error::Error;
+use base64;
+
+/// Codec for plain text content.
+pub struct PlainText;
+
+impl PlainText {
+    pub fn decode(s: &str) -> Result<Option<String>, Error> {
+        Ok(match s {
+            "" => None,
+            text => Some(text.to_owned()),
+        })
+    }
+
+    pub fn encode(string: &Option<String>) -> Option<String> {
+        string.as_ref().map(|text| text.to_owned())
+    }
+}
+
+/// Codec for trimmed plain text content.
+pub struct TrimmedPlainText;
+
+impl TrimmedPlainText {
+    pub fn decode(s: &str) -> Result<String, Error> {
+        Ok(match s.trim() {
+            "" => return Err(Error::ParseError("URI missing in uri.")),
+            text => text.to_owned(),
+        })
+    }
+
+    pub fn encode(string: &String) -> String {
+        string.to_owned()
+    }
+}
+
+/// Codec wrapping base64 encode/decode
+pub struct Base64;
+
+impl Base64 {
+    pub fn decode(s: &str) -> Result<Vec<u8>, Error> {
+        Ok(base64::decode(s)?)
+    }
+
+    pub fn encode(b: &Vec<u8>) -> Option<String> {
+        Some(base64::encode(b))
+    }
+}