Merge pull request #6 from tmccombs/yaml

Add support for YAML

2 files changed, 98 insertions, 0 deletions

diff --git a/src/file/mod.rs b/src/file/mod.rs
index 7e9d1a2..8f9578d 100644
--- a/src/file/mod.rs
+++ b/src/file/mod.rs
@@ -14,6 +14,9 @@ mod toml;
 #[cfg(feature = "json")]
 mod json;
 
+#[cfg(feature = "yaml")]
+mod yaml;
+
 #[derive(Clone, Copy)]
 pub enum FileFormat {
     /// TOML (parsed with toml)
@@ -23,6 +26,10 @@ pub enum FileFormat {
     /// JSON (parsed with serde_json)
     #[cfg(feature = "json")]
     Json,
+
+    /// YAML (parsed with yaml_rust)
+    #[cfg(feature = "yaml")]
+    Yaml,
 }
 
 impl FileFormat {
@@ -33,6 +40,9 @@ impl FileFormat {
 
             #[cfg(feature = "json")]
             FileFormat::Json => vec!["json"],
+
+            #[cfg(feature = "yaml")]
+            FileFormat::Yaml => vec!["yaml", "yml"],
         }
     }
 
@@ -44,6 +54,9 @@ impl FileFormat {
 
             #[cfg(feature = "json")]
             FileFormat::Json => json::Content::parse(text),
+
+            #[cfg(feature = "yaml")]
+            FileFormat::Yaml => yaml::Content::parse(text),
         }
     }
 }
diff --git a/src/file/yaml.rs b/src/file/yaml.rs
new file mode 100644
index 0000000..1c3ccbb
--- /dev/null
+++ b/src/file/yaml.rs
@@ -0,0 +1,85 @@
+use yaml_rust as yaml;
+
+use source::Source;
+use std::error::Error;
+use std::fmt;
+use std::collections::{BTreeMap, HashMap};
+use std::mem;
+use value::Value;
+
+
+pub struct Content {
+    // Root table of the YAML document
+    root: yaml::Yaml
+}
+
+impl Content {
+    pub fn parse(text: &str) -> Result<Box<Source>, Box<Error>> {
+        let mut docs = yaml::YamlLoader::load_from_str(text)?;
+
+        match docs.len() {
+            0 => Ok(Box::new(Content { root: yaml::Yaml::Hash(BTreeMap::new()) })),
+            1 => Ok(Box::new(Content {
+                root: mem::replace(&mut docs[0], yaml::Yaml::Null)
+            })),
+            n => Err(Box::new(MultipleDocumentsError(n)))
+        }
+    }
+
+    pub fn from_yaml(doc: yaml::Yaml) -> Content {
+        Content { root: doc }
+    }
+}
+
+fn from_yaml_value<'a>(value: &yaml::Yaml) -> Value {
+    match *value {
+        yaml::Yaml::String(ref value) => Value::String(value.clone()),
+        yaml::Yaml::Real(ref value) => Value::Float(value.parse::<f64>().unwrap()),
+        yaml::Yaml::Integer(value) => Value::Integer(value),
+        yaml::Yaml::Boolean(value) => Value::Boolean(value),
+        yaml::Yaml::Hash(ref table) => {
+            let mut m = HashMap::new();
+            for (key, value) in table {
+                if let Some(k) = key.as_str() {
+                    m.insert(k.to_owned(), from_yaml_value(value));
+                }
+                // TODO: should we do anything for non-string keys?
+            }
+            Value::Table(m)
+        }
+        yaml::Yaml::Array(ref array) => {
+            let l: Vec<Value> = array.iter().map(from_yaml_value).collect();
+            Value::Array(l)
+        }
+        // TODO: how should we handle Null and BadValue?
+        _ => { unimplemented!(); }
+
+    }
+}
+
+impl Source for Content {
+    fn collect(&self) -> HashMap<String, Value> {
+        if let Value::Table(table) = from_yaml_value(&self.root) {
+            table
+        } else {
+            // TODO: Better handle a non-object at root
+            // NOTE: I never want to support that but a panic is bad
+            panic!("expected object at YAML root");
+        }
+    }
+}
+
+#[derive(Debug, Copy, Clone)]
+struct MultipleDocumentsError(usize);
+
+impl fmt::Display for MultipleDocumentsError {
+    fn fmt(&self, format: &mut fmt::Formatter) -> fmt::Result {
+        write!(format, "Got {} YAML documents, expected 1", self.0)
+    }
+}
+
+impl Error for MultipleDocumentsError {
+    fn description(&self) -> &str {
+        "More than one YAML document provided"
+    }
+}