From 154169c521bf05921b432036583dabd07d8e2315 Mon Sep 17 00:00:00 2001
From: Ryan Leckey <leckey.ryan@gmail.com>
Date: Tue, 24 Jan 2017 10:26:09 -0800
Subject: Add API to access global config

---
 src/lib.rs | 345 ++++++++++---------------------------------------------------
 1 file changed, 54 insertions(+), 291 deletions(-)

(limited to 'src/lib.rs')

diff --git a/src/lib.rs b/src/lib.rs
index 75434b9..2192df1 100644
--- a/src/lib.rs
+++ b/src/lib.rs
@@ -1,321 +1,84 @@
 #![feature(try_from)]
+#![feature(drop_types_in_const)]
 
 extern crate toml;
 
 mod value;
 mod source;
+mod config;
 
-use value::Value;
-
-pub use source::Source;
-pub use source::File;
-
-use std::env;
 use std::error::Error;
 use std::convert::TryFrom;
-use std::collections::HashMap;
-
-#[derive(Default)]
-pub struct Config {
-    env_prefix: Option<String>,
-
-    defaults: HashMap<String, Value>,
-    overrides: HashMap<String, Value>,
-    environ: HashMap<String, Value>,
-    sources: Vec<HashMap<String, Value>>,
-}
-
-impl Config {
-    pub fn new() -> Config {
-        Default::default()
-    }
-
-    /// Merge in configuration values from the given source.
-    pub fn merge<T>(&mut self, mut source: T) -> Result<(), Box<Error>>
-        where T: Source
-    {
-        self.sources.push(source.build()?);
-
-        Ok(())
-    }
-
-    /// Defines a prefix that environment variables
-    /// must start with to be considered.
-    ///
-    /// By default all environment variables are considered. This can lead to unexpected values
-    /// in configuration (eg. `PATH`).
-    pub fn set_env_prefix(&mut self, prefix: &str) {
-        self.env_prefix = Some(prefix.to_uppercase());
-    }
-
-    /// Sets the default value for this key. The default value is only used
-    /// when no other value is provided.
-    pub fn set_default<T>(&mut self, key: &str, value: T)
-        where T: Into<Value>
-    {
-        self.defaults.insert(key.to_lowercase(), value.into());
-    }
-
-    /// Sets an override for this key.
-    pub fn set<T>(&mut self, key: &str, value: T)
-        where T: Into<Value>
-    {
-        self.overrides.insert(key.to_lowercase(), value.into());
-    }
-
-    pub fn get<'a, T>(&'a mut self, key: &str) -> Option<T>
-        where T: TryFrom<&'a mut Value>,
-              T: Default
-    {
-        // Check explicit override
-
-        if let Some(value) = self.overrides.get_mut(key) {
-            return T::try_from(value).ok();
-        }
-
-        // Check environment
+use std::sync::{Once, ONCE_INIT};
 
-        // Transform key into an env_key which is uppercased
-        // and has the optional prefix applied
-        let mut env_key = String::new();
-
-        if let Some(ref env_prefix) = self.env_prefix {
-            env_key.push_str(env_prefix);
-            env_key.push('_');
-        }
-
-        env_key.push_str(&key.to_uppercase());
-
-        if let Ok(value) = env::var(env_key.clone()) {
-            // Store the environment variable into an environ
-            // hash map; we want to return references
-            self.environ.insert(key.to_lowercase().into(), value.into());
+pub use source::Source;
+pub use source::File;
 
-            return T::try_from(self.environ.get_mut(key).unwrap()).ok();
-        }
+use value::Value;
 
-        // Check sources
+pub use config::Config;
 
-        for source in &mut self.sources.iter_mut().rev() {
-            if let Some(value) = source.get_mut(key) {
-                return T::try_from(value).ok();
-            }
-        }
+// Global configuration
+static mut CONFIG: Option<Config> = None;
+static CONFIG_INIT: Once = ONCE_INIT;
 
-        // Check explicit defaults
+// Get the global configuration instance
+fn global() -> Option<&'static mut Config> {
+    unsafe {
+        CONFIG_INIT.call_once(|| {
+            CONFIG = Some(Default::default());
+        });
 
-        if let Some(value) = self.defaults.get_mut(key) {
-            return T::try_from(value).ok();
+        // TODO(@rust): One-line this if possible
+        if let Some(ref mut c) = CONFIG {
+            return Some(c);
         }
 
         None
     }
-
-    pub fn get_str<'a>(&'a mut self, key: &str) -> Option<&'a str> {
-        self.get(key)
-    }
-
-    pub fn get_int(&mut self, key: &str) -> Option<i64> {
-        self.get(key)
-    }
-
-    pub fn get_float(&mut self, key: &str) -> Option<f64> {
-        self.get(key)
-    }
-
-    pub fn get_bool(&mut self, key: &str) -> Option<bool> {
-        self.get(key)
-    }
 }
 
-#[cfg(test)]
-mod test {
-    // use std::env;
-    use super::Config;
-
-    // Retrieval of a non-existent key
-    #[test]
-    fn test_not_found() {
-        let mut c = Config::new();
-
-        assert_eq!(c.get_int("key"), None);
-    }
-
-    // // Environment override
-    // #[test]
-    // fn test_env_override() {
-    //     let mut c = Config::new();
-
-    //     c.set_default("key_1", false);
-
-    //     env::set_var("KEY_1", "1");
-
-    //     assert_eq!(c.get_bool("key_1"), Some(true));
-
-    //     // TODO(@rust): Is there a way to easily kill this at the end of a test?
-    //     env::remove_var("KEY_1");
-    // }
-
-    // // Environment prefix
-    // #[test]
-    // fn test_env_prefix() {
-    //     let mut c = Config::new();
-
-    //     env::set_var("KEY_1", "1");
-    //     env::set_var("CFG_KEY_2", "false");
-
-    //     c.set_env_prefix("CFG");
-
-    //     assert_eq!(c.get_bool("key_1"), None);
-    //     assert_eq!(c.get_bool("key_2"), Some(false));
-
-    //     // TODO(@rust): Is there a way to easily kill this at the end of a test?
-    //     env::remove_var("KEY_1");
-    //     env::remove_var("CFG_KEY_2");
-    // }
-
-    // Explicit override
-    #[test]
-    fn test_default_override() {
-        let mut c = Config::new();
-
-        c.set_default("key_1", false);
-        c.set_default("key_2", false);
-
-        assert!(!c.get_bool("key_1").unwrap());
-        assert!(!c.get_bool("key_2").unwrap());
-
-        c.set("key_2", true);
-
-        assert!(!c.get_bool("key_1").unwrap());
-        assert!(c.get_bool("key_2").unwrap());
-    }
-
-    // Storage and retrieval of String values
-    #[test]
-    fn test_str() {
-        let mut c = Config::new();
-
-        c.set("key", "value");
-
-        assert_eq!(c.get_str("key").unwrap(), "value");
-        assert!("value" == c.get::<&str>("key").unwrap());
-    }
-
-    // Storage and retrieval of Boolean values
-    #[test]
-    fn test_bool() {
-        let mut c = Config::new();
-
-        c.set("key", true);
-
-        assert_eq!(c.get_bool("key").unwrap(), true);
-        assert!(false != c.get("key").unwrap());
-    }
-
-    // Storage and retrieval of Float values
-    #[test]
-    fn test_float() {
-        let mut c = Config::new();
-
-        c.set("key", 3.14);
-
-        assert_eq!(c.get_float("key").unwrap(), 3.14);
-        assert!(3.14 >= c.get("key").unwrap());
-    }
-
-    // Storage and retrieval of Integer values
-    #[test]
-    fn test_int() {
-        let mut c = Config::new();
-
-        c.set("key", 42);
-
-        assert_eq!(c.get_int("key").unwrap(), 42);
-        assert!(42 == c.get::<i64>("key").unwrap());
-    }
-
-    // Storage of various values and retrieval as String
-    #[test]
-    fn test_retrieve_str() {
-        let mut c = Config::new();
-
-        c.set("key_1", 115);
-        c.set("key_2", 1.23);
-        c.set("key_3", false);
-
-        assert_eq!(c.get_str("key_1"), Some("115"));
-        assert_eq!(c.get_str("key_2"), Some("1.23"));
-        assert_eq!(c.get_str("key_3"), Some("false"));
-    }
-
-    // Storage of various values and retrieval as Integer
-    #[test]
-    fn test_retrieve_int() {
-        let mut c = Config::new();
+pub fn merge<T>(source: T) -> Result<(), Box<Error>>
+    where T: Source
+{
+    global().unwrap().merge(source)
+}
 
-        c.set("key_1", "121");
-        c.set("key_2", 5.12);
-        c.set("key_3", 5.72);
-        c.set("key_4", false);
-        c.set("key_5", true);
-        c.set("key_6", "asga");
+pub fn set_env_prefix(prefix: &str) {
+    global().unwrap().set_env_prefix(prefix)
+}
 
-        assert_eq!(c.get_int("key_1"), Some(121));
-        assert_eq!(c.get_int("key_2"), Some(5));
-        assert_eq!(c.get_int("key_3"), Some(6));
-        assert_eq!(c.get_int("key_4"), Some(0));
-        assert_eq!(c.get_int("key_5"), Some(1));
-        assert_eq!(c.get_int("key_6"), None);
-    }
+pub fn set_default<T>(key: &str, value: T)
+    where T: Into<Value>
+{
+    global().unwrap().set_default(key, value)
+}
 
-    // Storage of various values and retrieval as Float
-    #[test]
-    fn test_retrieve_float() {
-        let mut c = Config::new();
+pub fn set<T>(key: &str, value: T)
+    where T: Into<Value>
+{
+    global().unwrap().set(key, value)
+}
 
-        c.set("key_1", "121");
-        c.set("key_2", "121.512");
-        c.set("key_3", 5);
-        c.set("key_4", false);
-        c.set("key_5", true);
-        c.set("key_6", "asga");
+pub fn get<'a, T>(key: &str) -> Option<T>
+    where T: TryFrom<&'a mut Value>,
+          T: Default
+{
+    global().unwrap().get(key)
+}
 
-        assert_eq!(c.get_float("key_1"), Some(121.0));
-        assert_eq!(c.get_float("key_2"), Some(121.512));
-        assert_eq!(c.get_float("key_3"), Some(5.0));
-        assert_eq!(c.get_float("key_4"), Some(0.0));
-        assert_eq!(c.get_float("key_5"), Some(1.0));
-        assert_eq!(c.get_float("key_6"), None);
-    }
+pub fn get_str<'a>(key: &str) -> Option<&'a str> {
+    global().unwrap().get_str(key)
+}
 
-    // Storage of various values and retrieval as Boolean
-    #[test]
-    fn test_retrieve_bool() {
-        let mut c = Config::new();
+pub fn get_int(key: &str) -> Option<i64> {
+    global().unwrap().get_int(key)
+}
 
-        c.set("key_1", "121");
-        c.set("key_2", "1");
-        c.set("key_3", "0");
-        c.set("key_4", "true");
-        c.set("key_5", "");
-        c.set("key_6", 51);
-        c.set("key_7", 0);
-        c.set("key_8", 12.12);
-        c.set("key_9", 1.0);
-        c.set("key_10", 0.0);
-        c.set("key_11", "asga");
+pub fn get_float(key: &str) -> Option<f64> {
+    global().unwrap().get_float(key)
+}
 
-        assert_eq!(c.get_bool("key_1"), Some(false));
-        assert_eq!(c.get_bool("key_2"), Some(true));
-        assert_eq!(c.get_bool("key_3"), Some(false));
-        assert_eq!(c.get_bool("key_4"), Some(true));
-        assert_eq!(c.get_bool("key_5"), Some(false));
-        assert_eq!(c.get_bool("key_6"), Some(true));
-        assert_eq!(c.get_bool("key_7"), Some(false));
-        assert_eq!(c.get_bool("key_8"), Some(true));
-        assert_eq!(c.get_bool("key_9"), Some(true));
-        assert_eq!(c.get_bool("key_10"), Some(false));
-        assert_eq!(c.get_bool("key_11"), Some(false));
-    }
+pub fn get_bool(key: &str) -> Option<bool> {
+    global().unwrap().get_bool(key)
 }
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