Implement: external::get_link()

libimaglink/src/external.rs

@@ -1,10 +1,26 @@
 use libimagstore::store::EntryHeader;
 
+use error::{LinkError, LinkErrorKind};
 use link::{Link, Links};
 use result::Result;
 
-pub fn get_link(header: &EntryHeader) -> Result<Link> {
-    unimplemented!()
+use toml::Value;
+use toml::Table;
+
+pub fn get_link(header: &EntryHeader) -> Result<Option<Link>> {
+    let uri = header.read("imag.content.uri");
+
+    if uri.is_err() {
+        let kind = LinkErrorKind::EntryHeaderReadError;
+        let lerr = LinkError::new(kind, Some(Box::new(uri.err().unwrap())));
+        return Err(lerr);
+    }
+    let uri = uri.unwrap();
+
+    match uri {
+        Some(Value::String(s)) => Ok(Some(Link::new(s))),
+        _ => Err(LinkError::new(LinkErrorKind::ExistingLinkTypeWrong, None)),
+    }
 }
 
 /// Set an external link in the header