feat(diff): Framework for change proofs

firewood/Cargo.toml

@@ -54,6 +54,7 @@ plain_hasher = "0.2.3"
 hex-literal = "1.0.0"
 env_logger = "0.11.7"
 hash-db = "0.16.0"
+metrics-util = "0.19.0"
 
 [[bench]]
 name = "hashops"

firewood/src/lib.rs

@@ -127,6 +127,9 @@ pub mod proof;
 /// Range proof module
 pub mod range_proof;
 
+/// Change proof module
+pub mod diff;
+
 /// Stream module, for both node and key-value streams
 pub mod stream;
 

firewood/src/merkle.rs

@@ -218,13 +218,11 @@ impl<T: TrieReader> Merkle<T> {
         PathIterator::new(&self.nodestore, key)
     }
 
-    #[allow(dead_code)]
-    pub(super) fn key_value_iter(&self) -> MerkleKeyValueStream<'_, T> {
+    pub(crate) fn key_value_iter(&self) -> MerkleKeyValueStream<'_, T> {
         MerkleKeyValueStream::from(&self.nodestore)
     }
 
-    #[allow(dead_code)]
-    pub(super) fn key_value_iter_from_key<K: AsRef<[u8]>>(
+    pub(crate) fn key_value_iter_from_key<K: AsRef<[u8]>>(
         &self,
         key: K,
     ) -> MerkleKeyValueStream<'_, T> {
@@ -255,7 +253,7 @@ impl<T: TrieReader> Merkle<T> {
         };
 
         // fetch the first key from the stream
-        let first_result = stream.next().await;
+        let first_result = StreamExt::next(&mut stream).await;
 
         // transpose the Option<Result<T, E>> to Result<Option<T>, E>
         // If this is an error, the ? operator will return it
@@ -287,25 +285,23 @@ impl<T: TrieReader> Merkle<T> {
         // we stop streaming if either we hit the limit or the key returned was larger
         // than the largest key requested
         key_values.extend(
-            stream
-                .take(limit.unwrap_or(usize::MAX))
-                .take_while(|kv| {
-                    // no last key asked for, so keep going
-                    let Some(last_key) = end_key else {
-                        return ready(true);
-                    };
+            StreamExt::take_while(StreamExt::take(stream, limit.unwrap_or(usize::MAX)), |kv| {
+                // no last key asked for, so keep going
+                let Some(last_key) = end_key else {
+                    return ready(true);
+                };
 
-                    // return the error if there was one
-                    let Ok(kv) = kv else {
-                        return ready(true);
-                    };
+                // return the error if there was one
+                let Ok(kv) = kv else {
+                    return ready(true);
+                };
 
-                    // keep going if the key returned is less than the last key requested
-                    ready(&*kv.0 <= last_key)
-                })
-                .map(|kv| kv.map(|(k, v)| (k, v.into())))
-                .try_collect::<Vec<(Box<[u8]>, Box<[u8]>)>>()
-                .await?,
+                // keep going if the key returned is less than the last key requested
+                ready(&*kv.0 <= last_key)
+            })
+            .map(|kv| kv.map(|(k, v)| (k, v.into())))
+            .try_collect::<Vec<(Box<[u8]>, Box<[u8]>)>>()
+            .await?,
         );
 
         let end_proof = key_values