Rewrite internal linking

* so you need to pass Entry instead of Link
* interal linking does two-way-linking

libimaglink/src/error.rs

@@ -9,6 +9,8 @@ pub enum LinkErrorKind {
     EntryHeaderReadError,
     EntryHeaderWriteError,
     ExistingLinkTypeWrong,
+    LinkTargetDoesNotExist,
+    InternalConversionError,
 }
 
 fn link_error_type_as_str(e: &LinkErrorKind) -> &'static str {
@@ -21,6 +23,12 @@ fn link_error_type_as_str(e: &LinkErrorKind) -> &'static str {
 
         &LinkErrorKind::ExistingLinkTypeWrong
             => "Existing link entry has wrong type",
+
+        &LinkErrorKind::LinkTargetDoesNotExist
+            => "Link target does not exist in the store",
+
+        &LinkErrorKind::InternalConversionError
+            => "Error while converting values internally",
     }
 }
 

libimaglink/src/internal.rs

@@ -1,80 +1,140 @@
+use libimagstore::storeid::StoreId;
 use libimagstore::store::Entry;
 use libimagstore::store::EntryHeader;
 use libimagstore::store::Result as StoreResult;
 
 use error::{LinkError, LinkErrorKind};
-use link::{Link, Links};
 use result::Result;
 
 use toml::Value;
 
+pub type Link = String;
+
 pub trait InternalLinker {
 
     /// Get the internal links from the implementor object
-    fn get_internal_links(&self) -> Result<Links>;
+    fn get_internal_links(&self) -> Result<Vec<Link>>;
 
     /// Set the internal links for the implementor object
-    fn set_internal_links(&mut self, links: Links) -> Result<Links>;
+    fn set_internal_links(&mut self, links: Vec<&mut Entry>) -> Result<Vec<Link>>;
 
     /// Add an internal link to the implementor object
-    fn add_internal_link(&mut self, link: Link) -> Result<()>;
+    fn add_internal_link(&mut self, link: &mut Entry) -> Result<()>;
 
     /// Remove an internal link from the implementor object
-    fn remove_internal_link(&mut self, link: Link) -> Result<()>;
-
-}
-
-impl InternalLinker for EntryHeader {
-
-    fn get_internal_links(self: &EntryHeader) -> Result<Links> {
-        process_rw_result(self.read("imag.links"))
-    }
-
-    /// Set the links in a header and return the old links, if any.
-    fn set_internal_links(&mut self, links: Links) -> Result<Links> {
-        let links : Vec<Link> = links.into();
-        let links : Vec<Value> = links.into_iter().map(|link| Value::String(link.into())).collect();
-        process_rw_result(self.set("imag.links", Value::Array(links)))
-    }
-
-    fn add_internal_link(&mut self, link: Link) -> Result<()> {
-        self.get_internal_links()
-            .and_then(|mut links| {
-                links.add(link);
-                self.set_internal_links(links).map(|_| ())
-            })
-    }
-
-    fn remove_internal_link(&mut self, link: Link) -> Result<()> {
-        self.get_internal_links()
-            .and_then(|mut links| {
-                links.remove(link);
-                self.set_internal_links(links).map(|_| ())
-            })
-    }
+    fn remove_internal_link(&mut self, link: &mut Entry) -> Result<()>;
 
 }
 
 impl InternalLinker for Entry {
 
-    fn get_internal_links(&self) -> Result<Links> {
-        self.get_header().get_internal_links()
+    fn get_internal_links(&self) -> Result<Vec<Link>> {
+        process_rw_result(self.get_header().read("imag.links"))
     }
 
-    fn set_internal_links(&mut self, links: Links) -> Result<Links> {
-        self.get_header_mut().set_internal_links(links)
+    /// Set the links in a header and return the old links, if any.
+    fn set_internal_links(&mut self, links: Vec<&mut Entry>) -> Result<Vec<Link>> {
+        let self_location = self.get_location().clone();
+        let mut new_links = vec![];
+
+        for link in links {
+            if let Err(e) = add_foreign_link(link, self_location.clone()) {
+                return Err(e);
+            }
+            let link = link.get_location().clone();
+            let link = link.to_str();
+            if link.is_none() {
+                return Err(LinkError::new(LinkErrorKind::InternalConversionError, None));
+            }
+            let link = link.unwrap();
+
+            new_links.push(Value::String(String::from(link)));
         }
 
-    fn add_internal_link(&mut self, link: Link) -> Result<()> {
-        self.get_header_mut().add_internal_link(link)
+        process_rw_result(self.get_header_mut().set("imag.links", Value::Array(new_links)))
     }
 
-    fn remove_internal_link(&mut self, link: Link) -> Result<()> {
-        self.get_header_mut().remove_internal_link(link)
+    fn add_internal_link(&mut self, link: &mut Entry) -> Result<()> {
+        let new_link = link.get_location().clone();
+        let new_link = new_link.to_str();
+        if new_link.is_none() {
+            return Err(LinkError::new(LinkErrorKind::InternalConversionError, None));
         }
+        let new_link = new_link.unwrap();
+
+        add_foreign_link(link, self.get_location().clone())
+            .and_then(|_| {
+                self.get_internal_links()
+                    .and_then(|mut links| {
+                        links.push(String::from(new_link));
+                        let links = links.into_iter().map(|s| Value::String(s)).collect();
+                        let process = self.get_header_mut().set("imag.links", Value::Array(links));
+                        process_rw_result(process)
+                            .map(|_| ())
+                    })
+            })
     }
 
-fn process_rw_result(links: StoreResult<Option<Value>>) -> Result<Links> {
+    fn remove_internal_link(&mut self, link: &mut Entry) -> Result<()> {
+        let own_loc = link.get_location().clone();
+        let own_loc = own_loc.to_str();
+        if own_loc.is_none() {
+            return Err(LinkError::new(LinkErrorKind::InternalConversionError, None));
+        }
+        let own_loc = own_loc.unwrap();
+
+        let other_loc = link.get_location().clone();
+        let other_loc = other_loc.to_str();
+        if other_loc.is_none() {
+            return Err(LinkError::new(LinkErrorKind::InternalConversionError, None));
+        }
+        let other_loc = other_loc.unwrap();
+
+        link.get_internal_links()
+            .and_then(|mut links| {
+                let links = links.into_iter()
+                    .filter(|l| l.clone() != own_loc)
+                    .map(|s| Value::String(s))
+                    .collect();
+                process_rw_result(link.get_header_mut().set("imag.links", Value::Array(links)))
+                    .map(|_| ())
+            })
+            .and_then(|_| {
+                self.get_internal_links()
+                    .and_then(|mut links| {
+                        let links = links
+                            .into_iter()
+                            .filter(|l| l.clone() != other_loc)
+                            .map(|s| Value::String(s))
+                            .collect();
+                        process_rw_result(self.get_header_mut().set("imag.links", Value::Array(links)))
+                            .map(|_| ())
+                    })
+            })
+    }
+
+}
+
+/// When Linking A -> B, the specification wants us to link back B -> A.
+/// This is a helper function which does this.
+fn add_foreign_link(target: &mut Entry, from: StoreId) -> Result<()> {
+    let from = from.to_str();
+    if from.is_none() {
+        debug!("Cannot convert pathbuf '{:?}' to String", from);
+        return Err(LinkError::new(LinkErrorKind::InternalConversionError, None));
+    }
+    let from = from.unwrap();
+
+    target.get_internal_links()
+        .and_then(|mut links| {
+            links.push(String::from(from));
+            let links = links.into_iter().map(|s| Value::String(s)).collect();
+            process_rw_result(target.get_header_mut().set("imag.links", Value::Array(links)))
+                .map(|_| ())
+        })
+}
+
+fn process_rw_result(links: StoreResult<Option<Value>>) -> Result<Vec<Link>> {
     if links.is_err() {
         let lerr  = LinkError::new(LinkErrorKind::EntryHeaderReadError,
                                    Some(Box::new(links.err().unwrap())));
@@ -89,12 +149,12 @@ fn process_rw_result(links: StoreResult<Option<Value>>) -> Result<Links> {
     let links : Vec<Link> = links.into_iter()
         .map(|link| {
             match link {
-                Value::String(s) => Link::new(s),
+                Value::String(s) => String::from(s),
                 _ => unreachable!(),
             }
         })
         .collect();
 
-    Ok(Links::new(links))
+    Ok(links)
 }
 

libimaglink/src/lib.rs

@@ -6,6 +6,5 @@ extern crate libimagstore;
 pub mod error;
 pub mod external;
 pub mod internal;
-pub mod link;
 pub mod result;