From bfc44c331a77d8c341c076e72df5ed0b56fbd422 Mon Sep 17 00:00:00 2001
From: Ryan Leckey <ryan@launchbadge.com>
Date: Thu, 1 Jun 2017 23:22:04 -0700
Subject: Move things around and get some tests in place

---
 src/config.rs | 104 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 104 insertions(+)
 create mode 100644 src/config.rs

(limited to 'src/config.rs')

diff --git a/src/config.rs b/src/config.rs
new file mode 100644
index 0000000..4d24a1d
--- /dev/null
+++ b/src/config.rs
@@ -0,0 +1,104 @@
+use std::collections::HashMap;
+use serde::de::Deserialize;
+
+use error::*;
+use source::Source;
+use value::Value;
+use path;
+
+enum ConfigKind {
+    // A mutable configuration. This is the default.
+    Mutable {
+        defaults: HashMap<String, Value>,
+        overrides: HashMap<String, Value>,
+        sources: Vec<Box<Source + Send + Sync>>,
+    },
+
+    // A frozen configuration.
+    // Configuration can no longer be mutated.
+    Frozen,
+}
+
+impl Default for ConfigKind {
+    fn default() -> Self {
+        ConfigKind::Mutable {
+            defaults: HashMap::new(),
+            overrides: HashMap::new(),
+            sources: Vec::new(),
+        }
+    }
+}
+
+/// A prioritized configuration repository. It maintains a set of
+/// configuration sources, fetches values to populate those, and provides
+/// them according to the source's priority.
+#[derive(Default)]
+pub struct Config {
+    kind: ConfigKind,
+
+    /// Root of the cached configuration.
+    pub cache: Value,
+}
+
+impl Config {
+    /// Merge in a configuration property source.
+    pub fn merge<T>(&mut self, source: T) -> Result<()>
+        where T: 'static,
+              T: Source + Send + Sync
+    {
+        match self.kind {
+            ConfigKind::Mutable { ref mut sources, .. } => {
+                sources.push(Box::new(source));
+            }
+
+            ConfigKind::Frozen => {
+                return Err(ConfigError::Frozen);
+            }
+        }
+
+        self.refresh()
+    }
+
+    /// Refresh the configuration cache with fresh
+    /// data from added sources.
+    ///
+    /// Configuration is automatically refreshed after a mutation
+    /// operation (`set`, `merge`, `set_default`, etc.).
+    pub fn refresh(&mut self) -> Result<()> {
+        self.cache = match self.kind {
+            // TODO: We need to actually merge in all the stuff
+            ConfigKind::Mutable {
+                ref overrides,
+                ref sources,
+                ref defaults,
+            } => sources[0].collect()?,
+
+            ConfigKind::Frozen => {
+                return Err(ConfigError::Frozen);
+            }
+        };
+
+        Ok(())
+    }
+
+    pub fn deserialize<T: Deserialize>(&self) -> Result<T> {
+        return T::deserialize(self.cache.clone());
+    }
+
+    pub fn get<T: Deserialize>(&self, key: &str) -> Result<T> {
+        // Parse the key into a path expression
+        let expr: path::Expression = key.to_lowercase().parse()?;
+
+        // Traverse the cache using the path to (possibly) retrieve a value
+        let value = expr.get(&self.cache).cloned();
+
+        match value {
+            Some(value) => {
+                // Deserialize the received value into the requested type
+                T::deserialize(value)
+            }
+
+            None => Err(ConfigError::NotFound(key.into())),
+        }
+    }
+}
-- 
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