Fix endianess in db_ledger to account for the default byte-comparator…

… used by Rocksdb (#1885)

src/db_ledger.rs

@@ -3,7 +3,7 @@
 //! access read to a persistent file-based ledger.
 
 use bincode::{deserialize, serialize};
-use byteorder::{ByteOrder, LittleEndian, ReadBytesExt};
+use byteorder::{BigEndian, ByteOrder, ReadBytesExt};
 use entry::Entry;
 use ledger::Block;
 use packet::{Blob, SharedBlob, BLOB_HEADER_SIZE};
@@ -103,7 +103,7 @@ pub struct MetaCf {}
 impl MetaCf {
     pub fn key(slot_height: u64) -> Vec<u8> {
         let mut key = vec![0u8; 8];
-        LittleEndian::write_u64(&mut key[0..8], slot_height);
+        BigEndian::write_u64(&mut key[0..8], slot_height);
         key
     }
 }
@@ -144,20 +144,20 @@ impl DataCf {
 
     pub fn key(slot_height: u64, index: u64) -> Vec<u8> {
         let mut key = vec![0u8; 16];
-        LittleEndian::write_u64(&mut key[0..8], slot_height);
-        LittleEndian::write_u64(&mut key[8..16], index);
+        BigEndian::write_u64(&mut key[0..8], slot_height);
+        BigEndian::write_u64(&mut key[8..16], index);
         key
     }
 
     pub fn slot_height_from_key(key: &[u8]) -> Result<u64> {
         let mut rdr = io::Cursor::new(&key[0..8]);
-        let height = rdr.read_u64::<LittleEndian>()?;
+        let height = rdr.read_u64::<BigEndian>()?;
         Ok(height)
     }
 
     pub fn index_from_key(key: &[u8]) -> Result<u64> {
         let mut rdr = io::Cursor::new(&key[8..16]);
-        let index = rdr.read_u64::<LittleEndian>()?;
+        let index = rdr.read_u64::<BigEndian>()?;
         Ok(index)
     }
 }
@@ -631,4 +631,44 @@ mod tests {
         DB::destroy(&Options::default(), &ledger_path)
             .expect("Expected successful database destruction");
     }
+
+    #[test]
+    pub fn test_iteration_order() {
+        let slot = 0;
+        // Create RocksDb ledger
+        let db_ledger_path = get_tmp_ledger_path("test_iteration_order");
+        {
+            let mut db_ledger = DbLedger::open(&db_ledger_path).unwrap();
+
+            // Write entries
+            let num_entries = 8;
+            let shared_blobs = make_tiny_test_entries(num_entries).to_blobs();
+
+            for (b, i) in shared_blobs.iter().zip(0..num_entries) {
+                b.write().unwrap().set_index(1 << (i * 8)).unwrap();
+            }
+
+            db_ledger
+                .write_shared_blobs(DEFAULT_SLOT_HEIGHT, &shared_blobs)
+                .expect("Expected successful write of blobs");
+            let mut db_iterator = db_ledger
+                .db
+                .raw_iterator_cf(db_ledger.data_cf.handle(&db_ledger.db))
+                .expect("Expected to be able to open database iterator");
+
+            db_iterator.seek(&DataCf::key(slot, 1));
+
+            // Iterate through ledger
+            for i in 0..num_entries {
+                assert!(db_iterator.valid());
+                let current_key = db_iterator.key().expect("Expected a valid key");
+                let current_index = DataCf::index_from_key(&current_key)
+                    .expect("Expect to be able to parse index from valid key");
+                assert_eq!(current_index, (1 as u64) << (i * 8));
+                db_iterator.next();
+            }
+        }
+        DB::destroy(&Options::default(), &db_ledger_path)
+            .expect("Expected successful database destruction");
+    }
 }