Add merge API with initial File Source

1 files changed, 95 insertions, 0 deletions

diff --git a/src/source.rs b/src/source.rs
new file mode 100644
index 0000000..bb3efd6
--- /dev/null
+++ b/src/source.rs
@@ -0,0 +1,95 @@
+use std::fs;
+use std::env;
+use std::error::Error;
+use std::io::Read;
+use std::collections::HashMap;
+
+use toml;
+
+use value::Value;
+
+pub trait Source {
+    fn build(&mut self) -> Result<HashMap<String, Value>, Box<Error>>;
+}
+
+#[derive(Default)]
+pub struct File {
+    // Basename of configuration file
+    name: String,
+
+    // Namespace to restrict configuration from the file
+    namespace: Option<String>,
+
+    // A required File will error if it cannot be found
+    required: bool,
+}
+
+impl File {
+    pub fn with_name(name: &str) -> File {
+        File {
+            name: name.into(),
+            required: true,
+
+            ..Default::default()
+        }
+    }
+
+    pub fn namespace(&mut self, namespace: &str) -> &mut File {
+        self.namespace = Some(namespace.into());
+        self
+    }
+
+    pub fn required(&mut self, required: bool) -> &mut File {
+        self.required = required;
+        self
+    }
+}
+
+fn collect(content: &mut HashMap<String, Value>, table: &toml::Table, prefix: Option<String>) {
+    for (key, value) in table {
+        // Construct full key from prefix
+        let key = if let Some(ref prefix) = prefix {
+            prefix.clone() + "." + key
+        } else {
+            key.clone()
+        };
+
+        match *value {
+            // Recurse into nested table
+            toml::Value::Table(ref table) => collect(content, table, Some(key)),
+
+            toml::Value::String(ref value) => {
+                content.insert(key, value.clone().into());
+            }
+
+            _ => {
+                // Unhandled
+            }
+        }
+    }
+}
+
+impl Source for File {
+    fn build(&mut self) -> Result<HashMap<String, Value>, Box<Error>> {
+        // Find file
+        // TODO: Use a nearest algorithm rather than strictly CWD
+        let cwd = env::current_dir()?;
+        let filename = cwd.join(self.name.clone() + ".toml");
+
+        // Read contents from file
+        let mut file = fs::File::open(filename)?;
+        let mut buffer = String::new();
+        file.read_to_string(&mut buffer)?;
+
+        // Parse
+        let mut parser = toml::Parser::new(&buffer);
+        // TODO: Get a solution to make this return an Error-able
+        let document = parser.parse().unwrap();
+
+        // Iterate through document and fill content
+        let mut content = HashMap::new();
+        collect(&mut content, &document, None);
+
+        Ok(content)
+    }
+}