Added CHANGELOG and support for deserialization using serde.

Author: MidasLamb

CHANGELOG.md

@@ -0,0 +1,26 @@
+# Changelog
+All notable changes to this project will be documented in this file.
+
+The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.0.0/),
+and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0.html).
+
+## [Unreleased]
+### Added
+
+### Changed
+
+### Removed
+
+## [0.2.0]
+### Added
+* `serde` support behind the `serde` feature flag.
+* `Eq, PartialEq, Ord, PartialOrd` are now implemented for `NonEmptyString`.
+* `get` to retrieve a reference to the inner value.
+
+### Changed
+* `new` constructor now returns a `Result` rather than an `Option`, which contains the original string 
+
+### Removed
+
+[Unreleased]: https://github.com/MidasLamb/non-empty-string/v0.2.0...HEAD
+[0.2.0]: https://github.com/MidasLamb/non-empty-string/compare/v0.1.0...v0.2.0

Cargo.toml

@@ -1,17 +1,23 @@
 [package]
 name = "non-empty-string"
-version = "0.1.0"
+version = "0.2.0"
 edition = "2018"
 authors = ["Midas Lambrichts <midaslamb@gmail.com>"]
 license = "MIT OR Apache-2.0"
 description = "A simple type for non empty Strings, similar to NonZeroUsize and friends."
 repository = "https://github.com/MidasLamb/non-empty-string"
-keywords = ["nonemptystring", "string", "str"]
+keywords = ["nonemptystring", "string", "str", "non-empty", "nonempty"]
 
 [lib]
 name = "non_empty_string"
 
 [dependencies]
+serde = { version = "1", optional = true }
 
 [dev-dependencies]
 assert_matches = "1.5.0"
+serde_json = { version = "1" }
+
+[features]
+default = []
+serde = ["dep:serde"]

src/lib.rs

@@ -1,21 +1,31 @@
 #![doc = include_str!("../README.md")]
 
+#[cfg(feature = "serde")]
+mod serde_support;
+
 /// A simple String wrapper type, similar to NonZeroUsize and friends.
 /// Guarantees that the String contained inside is not of length 0.
-#[derive(Debug, Clone)]
+#[derive(Debug, Clone, PartialEq, Eq, PartialOrd, Ord)]
+#[repr(transparent)]
 pub struct NonEmptyString(String);
 
 impl NonEmptyString {
     /// Attempts to create a new NonEmptyString.
-    /// If the given `string` is empty, `None` is returned, `Some` otherwise.
-    pub fn new(string: String) -> Option<NonEmptyString> {
+    /// If the given `string` is empty, `Err` is returned, containing the original `String`, `Ok` otherwise.
+    pub fn new(string: String) -> Result<NonEmptyString, String> {
         if string.is_empty() {
-            None
+            Err(string)
         } else {
-            Some(NonEmptyString(string))
+            Ok(NonEmptyString(string))
         }
     }
 
+    /// Returns a reference to the contained value.
+    pub fn get(&self) -> &str {
+        &self.0
+    }
+
+    /// Consume the `NonEmptyString` to get the internal `String` out.
     pub fn into_inner(self) -> String {
         self.0
     }
@@ -33,19 +43,31 @@ impl std::convert::AsRef<String> for NonEmptyString {
     }
 }
 
+impl<'s> std::convert::TryFrom<&'s str> for NonEmptyString {
+    type Error = ();
+
+    fn try_from(value: &'s str) -> Result<Self, Self::Error> {
+        if value.is_empty() {
+            Err(())
+        } else {
+            Ok(NonEmptyString::new(value.to_owned()).expect("Value is not empty"))
+        }
+    }
+}
+
 #[cfg(test)]
 mod tests {
     use super::*;
     use assert_matches::assert_matches;
 
     #[test]
     fn empty_string_returns_none() {
-        assert_matches!(NonEmptyString::new("".to_owned()), None);
+        assert_eq!(NonEmptyString::new("".to_owned()), Err("".to_owned()));
     }
 
     #[test]
     fn non_empty_string_returns_some() {
-        assert_matches!(NonEmptyString::new("string".to_owned()), Some(_));
+        assert_matches!(NonEmptyString::new("string".to_owned()), Ok(_));
     }
 
     #[test]
@@ -57,4 +79,25 @@ mod tests {
             "string".to_owned()
         );
     }
+
+    #[test]
+    fn as_ref_str_works() {
+        let nes = NonEmptyString::new("string".to_owned()).unwrap();
+        let val: &str = nes.as_ref();
+        assert_eq!(val, "string");
+    }
+
+    #[test]
+    fn as_ref_string_works() {
+        let nes = NonEmptyString::new("string".to_owned()).unwrap();
+        let val: &String = nes.as_ref();
+        assert_eq!(val, "string");
+    }
+
+    #[test]
+    fn calling_string_methods_works() {
+        let nes = NonEmptyString::new("string".to_owned()).unwrap();
+        // `len` is a `String` method.
+        assert!(nes.get().len() > 0);
+    }
 }

src/serde_support.rs

@@ -0,0 +1,67 @@
+use std::fmt;
+
+use serde::de::{self, Unexpected, Visitor};
+
+use crate::NonEmptyString;
+
+struct NonEmptyStringVisitor;
+
+impl<'de> de::Deserialize<'de> for NonEmptyString {
+    fn deserialize<D>(deserializer: D) -> Result<Self, D::Error>
+    where
+        D: serde::Deserializer<'de>,
+    {
+        deserializer.deserialize_string(NonEmptyStringVisitor)
+    }
+}
+
+pub enum DeserializeError {}
+
+type Result<T, E = DeserializeError> = std::result::Result<T, E>;
+
+impl<'de> Visitor<'de> for NonEmptyStringVisitor {
+    type Value = NonEmptyString;
+
+    fn expecting(&self, formatter: &mut fmt::Formatter) -> fmt::Result {
+        formatter.write_str("an integer between -2^31 and 2^31")
+    }
+
+    fn visit_str<E>(self, value: &str) -> Result<Self::Value, E>
+    where
+        E: de::Error,
+    {
+        self.visit_string(value.to_owned())
+    }
+
+    fn visit_string<E>(self, value: String) -> Result<Self::Value, E>
+    where
+        E: de::Error,
+    {
+        NonEmptyString::new(value).map_err(|e| de::Error::invalid_value(Unexpected::Str(&e), &self))
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+    use crate::*;
+    use assert_matches::assert_matches;
+    use serde_json::json;
+
+    #[test]
+    fn deserialize_works() {
+        let e: Result<NonEmptyString, _> = serde_json::from_value(json!("abc"));
+
+        let expected = NonEmptyString("abc".to_owned());
+
+        assert_matches!(e, Ok(v) if v == expected)
+    }
+
+    #[test]
+    fn deserialize_empty_fails() {
+        let e: Result<NonEmptyString, _> = serde_json::from_value(json!(""));
+
+        assert!(e.is_err());
+        // assert_matches!(e, Ok(expected))
+    }
+}