feat(dbg): Support yaml/json files via new Serde

toml isn't supported for now due to some problems.

To help with this, we are now doing test builds across various features to
make sure that both with and without the features works.

.travis.yml

@@ -13,8 +13,10 @@ install:
   - export PATH=$HOME/.cargo/bin:$PATH
 
 script:
-  - cargo build --features=cli
-  - cargo test --features=cli
+  - cargo check
+  - cargo check --features "cli"
+  - cargo check --features "cli serde_yaml serde_json"
+  - cargo test --features "cli serde_yaml serde_json"
   - if [ "$TRAVIS_RUST_VERSION" = "nightly" ]; then (cargo clippy --features=cli) fi
   - cargo fmt -- --write-mode=diff
 

Cargo.toml

@@ -22,7 +22,7 @@ doc = false
 
 [features]
 default = ["extra-filters"]
-cli = ["clap", "error-chain", "toml"]
+cli = ["clap", "error-chain", "serde_yaml"]
 extra-filters = []
 dev = []
 
@@ -37,7 +37,8 @@ serde_derive = "1.0"
 
 clap = { version = "2.22.0", optional = true }
 error-chain = { version = "0.10.0", optional = true }
-toml = { version = "0.3.2", optional = true }
+serde_yaml = { version = "0.7", optional = true }
+serde_json = { version = "1.0", optional = true }
 
 [build-dependencies]
 skeptic = "0.9"

appveyor.yml

@@ -27,8 +27,10 @@ install:
   - cargo -V
 
 test_script:
-  - cargo build --verbose --features=cli
-  - cargo test --features=cli
+  - cargo check --verbose
+  - cargo check --verbose --features "cli"
+  - cargo check --verbose --features "cli serde_yaml serde_json"
+  - cargo test --features "cli serde_yaml serde_json"
 
 cache:
   - C:\Users\appveyor\.cargo\registry

src/main.rs

@@ -3,32 +3,29 @@ extern crate clap;
 #[macro_use]
 extern crate error_chain;
 extern crate liquid;
-extern crate toml;
 
-use std::collections;
+#[cfg(feature = "serde_yaml")]
+extern crate serde_yaml;
+#[cfg(feature = "serde_json")]
+extern crate serde_json;
+
+use std::ffi;
 use std::fs;
 use std::io;
-use std::io::{Write, Read};
+use std::io::Write;
 use std::path;
 use liquid::Renderable;
 
-macro_rules! println_stderr(
-    ($($arg:tt)*) => { {
-        let r = writeln!(&mut ::std::io::stderr(), $($arg)*);
-        r.expect("failed printing to stderr");
-    } }
-);
-
 error_chain! {
-
     links {
     }
 
     foreign_links {
         Clap(clap::Error);
         Io(io::Error);
         Liquid(liquid::Error);
-        Toml(toml::de::Error);
+        Yaml(serde_yaml::Error) #[cfg(feature = "serde_yaml")];
+        Json(serde_json::Error) #[cfg(feature = "serde_json")];
     }
 
     errors {
@@ -39,43 +36,40 @@ fn option<'a>(name: &'a str, value: &'a str) -> clap::Arg<'a, 'a> {
     clap::Arg::with_name(name).long(name).value_name(value)
 }
 
-fn convert_value(toml_value: &toml::Value) -> Result<liquid::Value> {
-    match *toml_value {
-        toml::Value::String(ref s) => Ok(liquid::Value::Str(s.to_string())),
-        toml::Value::Integer(n) => Ok(liquid::Value::Num(n as f32)),
-        toml::Value::Float(n) => Ok(liquid::Value::Num(n as f32)),
-        toml::Value::Boolean(b) => Ok(liquid::Value::Bool(b)),
-        toml::Value::Datetime(_) => Err("Datetime's are unsupported".into()),
-        toml::Value::Array(ref a) => {
-            let liquid_array: Result<Vec<liquid::Value>> = a.iter().map(convert_value).collect();
-            let liquid_array = liquid_array?;
-            Ok(liquid::Value::Array(liquid_array))
-        }
-        toml::Value::Table(ref t) => {
-            let liquid_object: Result<collections::HashMap<String, liquid::Value>> = t.iter()
-                .map(|(k, v)| {
-                    let v = convert_value(v);
-                    match v {
-                        Ok(v) => Ok((k.to_string(), v)),
-                        Err(e) => Err(e),
-                    }
-                })
-                .collect();
-            let liquid_object = liquid_object?;
-            Ok(liquid::Value::Object(liquid_object))
-        }
-    }
+#[cfg(feature = "serde_yaml")]
+fn load_yaml(path: &path::Path) -> Result<liquid::Value> {
+    let f = fs::File::open(path)?;
+    serde_yaml::from_reader(f).map_err(|e| e.into())
+}
+
+#[cfg(not(feature = "serde_yaml"))]
+fn load_yaml(path: &path::Path) -> Result<liquid::Value> {
+    bail!("yaml is unsupported");
+}
+
+#[cfg(feature = "serde_json")]
+fn load_json(path: &path::Path) -> Result<liquid::Value> {
+    let f = fs::File::open(path)?;
+    serde_json::from_reader(f).map_err(|e| e.into())
+}
+
+#[cfg(not(feature = "serde_json"))]
+fn load_json(path: &path::Path) -> Result<liquid::Value> {
+    bail!("json is unsupported");
 }
 
 fn build_context(path: &path::Path) -> Result<liquid::Context> {
-    let mut input = String::new();
-    let mut f = fs::File::open(path)?;
-    f.read_to_string(&mut input)?;
-    let input: toml::Value = input.parse()?;
-    let value = convert_value(&input)?;
+    let extension = path.extension().unwrap_or_else(|| ffi::OsStr::new(""));
+    let value = if extension == ffi::OsStr::new("yaml") {
+        load_yaml(path)
+    } else if extension == ffi::OsStr::new("yaml") {
+        load_json(path)
+    } else {
+        Err("Unsupported file type".into())
+    }?;
     let value = match value {
         liquid::Value::Object(o) => Ok(o),
-        _ => Err("File must be a toml table"),
+        _ => Err("File must be an object"),
     }?;
     let data = liquid::Context::with_values(value);