Enforce ordering for bundles with duplicate chunks (closes #13)

src/bundledb/mod.rs

@@ -21,7 +21,7 @@ pub static HEADER_STRING: [u8; 7] = *b"zvault\x01";
 pub static HEADER_VERSION: u8 = 1;
 
 
-#[derive(Hash, PartialEq, Eq, Clone, Default)]
+#[derive(Hash, PartialEq, Eq, Clone, Default, Ord, PartialOrd)]
 pub struct BundleId(pub Hash);
 
 impl Serialize for BundleId {

src/index.rs

@@ -341,13 +341,13 @@ impl Index {
     }
 
     /// Adds the key, data pair into the table.
-    /// If the key existed in the table before, it is overwritten and false is returned.
-    /// Otherwise it will be added to the table and true is returned.
-    pub fn set(&mut self, key: &Hash, data: &Location) -> Result<bool, IndexError> {
+    /// If the key existed the old data is returned.
+    pub fn set(&mut self, key: &Hash, data: &Location) -> Result<Option<Location>, IndexError> {
         match self.locate(key) {
             LocateResult::Found(pos) => {
-                self.data[pos].data = *data;
-                Ok(false)
+                let mut old = *data;
+                mem::swap(&mut old, &mut self.data[pos].data);
+                Ok(Some(old))
             },
             LocateResult::Hole(pos) => {
                 {
@@ -356,7 +356,7 @@ impl Index {
                     entry.data = *data;
                 }
                 try!(self.increase_count());
-                Ok(true)
+                Ok(None)
             },
             LocateResult::Steal(pos) => {
                 let mut stolen_key;
@@ -382,7 +382,7 @@ impl Index {
                     }
                 }
                 try!(self.increase_count());
-                Ok(true)
+                Ok(None)
             }
         }
     }

src/repository/mod.rs

@@ -268,7 +268,7 @@ impl Repository {
             BundleMode::Meta => self.next_meta_bundle
         };
         let chunks = try!(self.bundles.get_chunk_list(&bundle.id));
-        self.bundle_map.set(bundle_id, bundle.id);
+        self.bundle_map.set(bundle_id, bundle.id.clone());
         if self.next_meta_bundle == bundle_id {
             self.next_meta_bundle = self.next_free_bundle_id()
         }
@@ -276,7 +276,13 @@ impl Repository {
             self.next_data_bundle = self.next_free_bundle_id()
         }
         for (i, (hash, _len)) in chunks.into_inner().into_iter().enumerate() {
-            try!(self.index.set(&hash, &Location{bundle: bundle_id as u32, chunk: i as u32}));
+            if let Some(old) = try!(self.index.set(&hash, &Location{bundle: bundle_id as u32, chunk: i as u32})) {
+                // Duplicate chunk, forced ordering: higher bundle id wins
+                let old_bundle_id = try!(self.get_bundle_id(old.bundle));
+                if old_bundle_id > bundle.id {
+                    try!(self.index.set(&hash, &old));
+                }
+            }
         }
         Ok(())
     }

src/util/hash.rs

@@ -13,7 +13,7 @@ use std::io::{self, Read, Write};
 
 
 #[repr(packed)]
-#[derive(Clone, Copy, PartialEq, Hash, Eq, Default)]
+#[derive(Clone, Copy, PartialEq, Hash, Eq, Default, Ord, PartialOrd)]
 pub struct Hash {
     pub high: u64,
     pub low: u64