Propagate Cow into Source

src/config.rs

@@ -81,23 +81,23 @@ impl<'a> ConfigStore<'a> {
         }
     }
 
-    fn get(&self, key: &str) -> Option<Value> {
+    fn get(&self, key: &str) -> Option<Cow<'a, Value>> {
         if let ConfigStore::Mutable { ref overrides, ref sources, ref defaults } = *self {
             // Check explicit override
             if let Some(value) = overrides.get(key) {
-                return Some(value.clone());
+                return Some(Cow::Borrowed(value));
             }
 
             // Check sources
             for source in &mut sources.iter().rev() {
                 if let Some(value) = source.get(key) {
-                    return Some(value);
+                    return Some(value)
                 }
             }
 
             // Check explicit defaults
             if let Some(value) = defaults.get(key) {
-                return Some(value.clone());
+                return Some(Cow::Borrowed(value));
             }
         }
 
@@ -154,7 +154,7 @@ impl<'a> Config<'a> {
     }
 
     pub fn get(&self, key: &str) -> Option<Cow<'a, Value>> {
-        self.store.get(key).map(Cow::Owned)
+        self.store.get(key)
     }
 
     pub fn get_str(&'a self, key: &str) -> Option<Cow<'a, str>> {

src/env.rs

@@ -1,5 +1,6 @@
 use std::env;
 use std::error::Error;
+use std::borrow::Cow;
 
 use source;
 use value::Value;
@@ -26,7 +27,7 @@ impl source::SourceBuilder for Environment {
 }
 
 impl source::Source for Environment {
-    fn get(&self, key: &str) -> Option<Value> {
+    fn get<'a>(&self, key: &str) -> Option<Cow<'a, Value>> {
         let mut env_key = String::new();
 
         // Apply prefix
@@ -38,6 +39,6 @@ impl source::Source for Environment {
         env_key.push_str(&key.to_uppercase());
 
         // Attempt to retreive environment variable and coerce into a Value
-        env::var(env_key.clone()).ok().map(Value::from)
+        env::var(env_key.clone()).ok().map(Value::from).map(Cow::Owned)
     }
 }

src/file/json.rs

@@ -19,28 +19,28 @@ impl Content {
     }
 }
 
-fn from_json_value(value: &serde_json::Value) -> Option<Value> {
+fn from_json_value<'a>(value: &serde_json::Value) -> Option<Cow<'a, Value>> {
     match *value {
-        serde_json::Value::String(ref value) => Some(Value::String(Cow::Borrowed(value))),
+        serde_json::Value::String(ref value) => Some(Cow::Owned(Value::String(Cow::Borrowed(value)))),
 
         serde_json::Value::Number(ref value) => {
             if let Some(value) = value.as_i64() {
-                Some(Value::Integer(value))
+                Some(Cow::Owned(Value::Integer(value)))
             } else if let Some(value) = value.as_f64() {
-                Some(Value::Float(value))
+                Some(Cow::Owned(Value::Float(value)))
             } else {
                 None
             }
         }
 
-        serde_json::Value::Bool(value) => Some(Value::Boolean(value)),
+        serde_json::Value::Bool(value) => Some(Cow::Owned(Value::Boolean(value))),
 
         _ => None,
     }
 }
 
 impl Source for Content {
-    fn get(&self, key: &str) -> Option<Value> {
+    fn get<'a>(&self, key: &str) -> Option<Cow<'a, Value>> {
         // TODO: Key segment iteration is not something that should be here directly
         let key_delim = '.';
         let key_segments = key.split(key_delim);

src/file/nil.rs

@@ -1,11 +1,13 @@
+use std::borrow::Cow;
+
 use source::Source;
 use value::Value;
 
 // Nil source that does nothing to easily allow for optional files
 pub struct Nil {}
 
 impl Source for Nil {
-    fn get(&self, _: &str) -> Option<Value> {
+    fn get<'a>(&self, _: &str) -> Option<Cow<'a, Value>> {
         None
     }
 }

src/file/toml.rs

@@ -20,19 +20,19 @@ impl Content {
     }
 }
 
-fn from_toml_value(value: &toml::Value) -> Option<Value> {
+fn from_toml_value<'a>(value: &toml::Value) -> Option<Cow<'a, Value>> {
     match *value {
-        toml::Value::String(ref value) => Some(Value::String(Cow::Borrowed(value))),
-        toml::Value::Float(value) => Some(Value::Float(value)),
-        toml::Value::Integer(value) => Some(Value::Integer(value)),
-        toml::Value::Boolean(value) => Some(Value::Boolean(value)),
+        toml::Value::String(ref value) => Some(Cow::Owned(Value::String(Cow::Borrowed(value)))),
+        toml::Value::Float(value) => Some(Cow::Owned(Value::Float(value))),
+        toml::Value::Integer(value) => Some(Cow::Owned(Value::Integer(value))),
+        toml::Value::Boolean(value) => Some(Cow::Owned(Value::Boolean(value))),
 
         _ => None,
     }
 }
 
 impl Source for Content {
-    fn get(&self, key: &str) -> Option<Value> {
+    fn get<'a>(&self, key: &str) -> Option<Cow<'a, Value>> {
         // TODO: Key segment iteration is not something that should be here directly
         let key_delim = '.';
         let key_segments = key.split(key_delim);

src/source.rs

@@ -1,9 +1,10 @@
 use std::error::Error;
+use std::borrow::Cow;
 
 use value::Value;
 
 pub trait Source {
-    fn get(&self, key: &str) -> Option<Value>;
+    fn get<'a>(&self, key: &str) -> Option<Cow<'a, Value>>;
 }
 
 pub trait SourceBuilder {

src/value.rs

@@ -20,10 +20,7 @@ impl<'a> Value<'a> {
     /// Gets the underlying value as a string, performing a conversion only if neccessary.
     pub fn as_str(&'a self) -> Option<Cow<'a, str>> {
         if let Value::String(ref value) = *self {
-            Some(match *value {
-                Cow::Borrowed(v) => Cow::Borrowed(v),
-                Cow::Owned(ref v) => Cow::Borrowed(v),
-            })
+            Some(Cow::Borrowed(&*value))
         } else if let Value::Integer(value) = *self {
             Some(Cow::Owned(value.to_string()))
         } else if let Value::Float(value) = *self {