Support format json5

10 files changed, 239 insertions, 5 deletions

diff --git a/Cargo.toml b/Cargo.toml
index ca28c06..929f7ff 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -15,11 +15,12 @@ edition = "2018"
 maintenance = { status = "actively-developed" }
 
 [features]
-default = ["toml", "json", "yaml", "hjson", "ini", "ron"]
+default = ["toml", "json", "yaml", "hjson", "ini", "ron", "json5"]
 json = ["serde_json"]
 yaml = ["yaml-rust"]
 hjson = ["serde-hjson"]
 ini = ["rust-ini"]
+json5 = ["json5_rs", "serde_derive"]
 
 [dependencies]
 lazy_static = "1.0"
@@ -32,6 +33,8 @@ yaml-rust = { version = "0.4", optional = true }
 serde-hjson = { version = "0.9", default-features = false, optional = true }
 rust-ini = { version = "0.17", optional = true }
 ron = { version = "0.6", optional = true }
+json5_rs = { version = "0.3", optional = true, package = "json5" }
+serde_derive = { version = "1.0.8", optional = true }
 
 [dev-dependencies]
 serde_derive = "1.0.8"
diff --git a/README.md b/README.md
index 7f43c62..07fcadf 100644
--- a/README.md
+++ b/README.md
@@ -1,4 +1,5 @@
 # config-rs
+
 ![Rust](https://img.shields.io/badge/rust-stable-brightgreen.svg)
 [![Build Status](https://travis-ci.org/mehcode/config-rs.svg?branch=master)](https://travis-ci.org/mehcode/config-rs)
 [![Crates.io](https://img.shields.io/crates/d/config.svg)](https://crates.io/crates/config)
@@ -10,7 +11,7 @@
 
  - Set defaults
  - Set explicit values (to programmatically override)
- - Read from [JSON], [TOML], [YAML], [HJSON], [INI], [RON] files
+ - Read from [JSON], [TOML], [YAML], [HJSON], [INI], [RON], [JSON5] files
  - Read from environment
  - Loosely typed — Configuration values may be read in any supported type, as long as there exists a reasonable conversion
  - Access nested fields using a formatted path — Uses a subset of JSONPath; currently supports the child ( `redis.port` ) and subscript operators ( `databases[0].name` )
@@ -21,6 +22,7 @@
 [HJSON]: https://github.com/hjson/hjson-rust
 [INI]: https://github.com/zonyitoo/rust-ini
 [RON]: https://github.com/ron-rs/ron
+[JSON5]: https://github.com/callum-oakley/json5-rs
 
 ## Usage
 
@@ -35,6 +37,7 @@ config = "0.11"
  - `yaml` - Adds support for reading YAML files
  - `toml` - Adds support for reading TOML files
  - `ron` - Adds support for reading RON files
+ - `json5` - Adds support for reading JSON5 files
 
 See the [documentation](https://docs.rs/config) or [examples](https://github.com/mehcode/config-rs/tree/master/examples) for
 more usage information.
diff --git a/src/error.rs b/src/error.rs
index 28142b5..9778649 100644
--- a/src/error.rs
+++ b/src/error.rs
@@ -94,6 +94,18 @@ impl ConfigError {
         }
     }
 
+    // Have a proper error fire if the root of a file is ever not a Table
+    // TODO: for now only json5 checked, need to finish others
+    #[doc(hidden)]
+    pub fn invalid_root(origin: Option<&String>, unexpected: Unexpected) -> Box<Self> {
+        Box::new(ConfigError::Type {
+            origin: origin.map(|s| s.to_owned()),
+            unexpected,
+            expected: "a map",
+            key: None,
+        })
+    }
+
     // FIXME: pub(crate)
     #[doc(hidden)]
     pub fn extend_with_key(self, key: &str) -> Self {
diff --git a/src/file/format/json5.rs b/src/file/format/json5.rs
new file mode 100644
index 0000000..320e574
--- /dev/null
+++ b/src/file/format/json5.rs
@@ -0,0 +1,78 @@
+use serde_derive::Deserialize;
+
+use std::collections::HashMap;
+use std::error::Error;
+
+use crate::error::{ConfigError, Unexpected};
+use crate::value::{Value, ValueKind};
+
+#[derive(Deserialize, Debug)]
+#[serde(untagged)]
+pub enum Val {
+    Null,
+    Boolean(bool),
+    Integer(i64),
+    Float(f64),
+    String(String),
+    Array(Vec<Val>),
+    Object(HashMap<String, Val>),
+}
+
+pub fn parse(
+    uri: Option<&String>,
+    text: &str,
+) -> Result<HashMap<String, Value>, Box<dyn Error + Send + Sync>> {
+    let root = json5_rs::from_str::<Val>(&text)?;
+    if let Some(err) = match root {
+        Val::String(ref value) => Some(Unexpected::Str(value.clone())),
+        Val::Integer(value) => Some(Unexpected::Integer(value)),
+        Val::Float(value) => Some(Unexpected::Float(value)),
+        Val::Boolean(value) => Some(Unexpected::Bool(value)),
+        Val::Object(_) => None,
+        Val::Array(_) => Some(Unexpected::Seq),
+        Val::Null => Some(Unexpected::Unit),
+    } {
+        return Err(ConfigError::invalid_root(uri, err));
+    }
+
+    let value = from_json5_value(uri, root);
+    match value.kind {
+        ValueKind::Table(map) => Ok(map),
+
+        _ => Ok(HashMap::new()),
+    }
+}
+
+fn from_json5_value(uri: Option<&String>, value: Val) -> Value {
+    match value {
+        Val::String(v) => Value::new(uri, ValueKind::String(v)),
+
+        Val::Integer(v) => Value::new(uri, ValueKind::Integer(v)),
+
+        Val::Float(v) => Value::new(uri, ValueKind::Float(v)),
+
+        Val::Boolean(v) => Value::new(uri, ValueKind::Boolean(v)),
+
+        Val::Object(table) => {
+            let mut m = HashMap::new();
+
+            for (key, value) in table {
+                m.insert(key, from_json5_value(uri, value));
+            }
+
+            Value::new(uri, ValueKind::Table(m))
+        }
+
+        Val::Array(array) => {
+            let mut l = Vec::new();
+
+            for value in array {
+                l.push(from_json5_value(uri, value));
+            }
+
+            Value::new(uri, ValueKind::Array(l))
+        }
+
+        Val::Null => Value::new(uri, ValueKind::Nil),
+    }
+}
diff --git a/src/file/format/mod.rs b/src/file/format/mod.rs
index bbd62a2..53bacf6 100644
--- a/src/file/format/mod.rs
+++ b/src/file/format/mod.rs
@@ -25,6 +25,9 @@ mod ini;
 #[cfg(feature = "ron")]
 mod ron;
 
+#[cfg(feature = "json5")]
+mod json5;
+
 #[derive(Debug, Clone, Copy, Eq, PartialEq, Hash)]
 pub enum FileFormat {
     /// TOML (parsed with toml)
@@ -42,6 +45,7 @@ pub enum FileFormat {
     /// HJSON (parsed with serde_hjson)
     #[cfg(feature = "hjson")]
     Hjson,
+
     /// INI (parsed with rust_ini)
     #[cfg(feature = "ini")]
     Ini,
@@ -49,6 +53,10 @@ pub enum FileFormat {
     /// RON (parsed with ron)
     #[cfg(feature = "ron")]
     Ron,
+
+    /// JSON5 (parsed with json5)
+    #[cfg(feature = "json5")]
+    Json5,
 }
 
 lazy_static! {
@@ -75,6 +83,9 @@ lazy_static! {
         #[cfg(feature = "ron")]
         formats.insert(FileFormat::Ron, vec!["ron"]);
 
+        #[cfg(feature = "json5")]
+        formats.insert(FileFormat::Json5, vec!["json5"]);
+
         formats
     };
 }
@@ -115,6 +126,9 @@ impl FileFormat {
 
             #[cfg(feature = "ron")]
             FileFormat::Ron => ron::parse(uri, text),
+
+            #[cfg(feature = "json5")]
+            FileFormat::Json5 => json5::parse(uri, text),
         }
     }
 }
diff --git a/src/lib.rs b/src/lib.rs
index ae02c36..986f36a 100644
--- a/src/lib.rs
+++ b/src/lib.rs
@@ -6,7 +6,7 @@
 //!  - Environment variables
 //!  - Another Config instance
 //!  - Remote configuration: etcd, Consul
-//!  - Files: TOML, JSON, YAML, HJSON, INI, RON
+//!  - Files: TOML, JSON, YAML, HJSON, INI, RON, JSON5
 //!  - Manual, programmatic override (via a `.set` method on the Config instance)
 //!
 //! Additionally, Config supports:
@@ -24,8 +24,7 @@
 #[macro_use]
 extern crate serde;
 
-#[cfg(test)]
-#[macro_use]
+#[cfg(any(test, feature = "json5"))]
 extern crate serde_derive;
 
 extern crate nom;
@@ -51,6 +50,9 @@ extern crate ini;
 #[cfg(feature = "ron")]
 extern crate ron;
 
+#[cfg(feature = "json5")]
+extern crate json5_rs;
+
 mod builder;
 mod config;
 mod de;
diff --git a/tests/Settings-invalid.json5 b/tests/Settings-invalid.json5
new file mode 100644
index 0000000..7e97bc1
--- /dev/null
+++ b/tests/Settings-invalid.json5
@@ -0,0 +1,4 @@
+{
+  ok: true
+  error
+}
diff --git a/tests/Settings.json5 b/tests/Settings.json5
new file mode 100644
index 0000000..cfab1f5
--- /dev/null
+++ b/tests/Settings.json5
@@ -0,0 +1,18 @@
+{
+  // c
+  /* c */
+  debug: true,
+  production: false,
+  arr: [1, 2, 3, 4, 5, 6, 7, 8, 9, 10,],
+  place: {
+    name: 'Torre di Pisa',
+    longitude: 43.7224985,
+    latitude: 10.3970522,
+    favorite: false,
+    reviews: 3866,
+    rating: 4.5,
+    creator: {
+      name: "John Smith",
+    }
+  }
+}
diff --git a/tests/errors.rs b/tests/errors.rs
index 54bbe95..e11ad69 100644
--- a/tests/errors.rs
+++ b/tests/errors.rs
@@ -137,3 +137,20 @@ inner:
         panic!("Wrong error {:?}", e);
     }
 }
+
+#[test]
+fn test_error_root_not_table() {
+    match Config::builder()
+        .add_source(File::from_str(r#"false"#, FileFormat::Json5))
+        .build()
+    {
+        Ok(_) => panic!("Should not merge if root is not a table"),
+        Err(e) => match e {
+            ConfigError::FileParse { cause, .. } => assert_eq!(
+                "invalid type: boolean `false`, expected a map",
+                format!("{}", cause)
+            ),
+            _ => panic!("Wrong error: {:?}", e),
+        },
+    }
+}
diff --git a/tests/file_json5.rs b/tests/file_json5.rs
new file mode 100644
index 0000000..d22b726
--- /dev/null
+++ b/tests/file_json5.rs
@@ -0,0 +1,83 @@
+#![cfg(feature = "json5")]
+
+extern crate config;
+extern crate float_cmp;
+extern crate serde;
+
+#[macro_use]
+extern crate serde_derive;
+
+use config::*;
+use float_cmp::ApproxEqUlps;
+use std::collections::HashMap;
+use std::path::PathBuf;
+
+#[derive(Debug, Deserialize)]
+struct Place {
+    name: String,
+    longitude: f64,
+    latitude: f64,
+    favorite: bool,
+    telephone: Option<String>,
+    reviews: u64,
+    creator: HashMap<String, Value>,
+    rating: Option<f32>,
+}
+
+#[derive(Debug, Deserialize)]
+struct Settings {
+    debug: f64,
+    production: Option<String>,
+    place: Place,
+    #[serde(rename = "arr")]
+    elements: Vec<String>,
+}
+
+fn make() -> Config {
+    Config::builder()
+        .add_source(File::new("tests/Settings", FileFormat::Json5))
+        .build()
+        .unwrap()
+}
+
+#[test]
+fn test_file() {
+    let c = make();
+
+    // Deserialize the entire file as single struct
+    let s: Settings = c.try_into().unwrap();
+
+    assert!(s.debug.approx_eq_ulps(&1.0, 2));
+    assert_eq!(s.production, Some("false".to_string()));
+    assert_eq!(s.place.name, "Torre di Pisa");
+    assert!(s.place.longitude.approx_eq_ulps(&43.7224985, 2));
+    assert!(s.place.latitude.approx_eq_ulps(&10.3970522, 2));
+    assert_eq!(s.place.favorite, false);
+    assert_eq!(s.place.reviews, 3866);
+    assert_eq!(s.place.rating, Some(4.5));
+    assert_eq!(s.place.telephone, None);
+    assert_eq!(s.elements.len(), 10);
+    assert_eq!(s.elements[3], "4".to_string());
+    assert_eq!(
+        s.place.creator["name"].clone().into_string().unwrap(),
+        "John Smith".to_string()
+    );
+}
+
+#[test]
+fn test_error_parse() {
+    let res = Config::builder()
+        .add_source(File::new("tests/Settings-invalid", FileFormat::Json5))
+        .build();
+
+    let path_with_extension: PathBuf = ["tests", "Settings-invalid.json5"].iter().collect();
+
+    assert!(res.is_err());
+    assert_eq!(
+        res.unwrap_err().to_string(),
+        format!(
+            " --> 2:7\n  |\n2 |   ok: true␊\n  |       ^---\n  |\n  = expected null in {}",
+            path_with_extension.display()
+        )
+    );
+}