feat!: update Orchard witness calculation

Now uses Frontier

librustzcash-wrapper/src/lib.rs

@@ -1548,9 +1548,10 @@ pub extern "C" fn rust_wrapper_read_orchard_witness(
     out: *mut u8,
     out_len: &mut usize
     ){
-    let tree_in: Vec<u8> = marshall_from_haskell_var(tree, tree_len, RW);
-    let tree_reader = Cursor::new(tree_in);
-    let ct: CommitmentTree<MerkleHashOrchard, 32> = read_commitment_tree(tree_reader).unwrap();
+    let tree_in: Hfrontier = marshall_from_haskell_var(tree, tree_len, RW);
+    let leaf = MerkleHashOrchard::from_bytes(&to_array(tree_in.leaf.bytes)).unwrap();
+    let frontier: Frontier<MerkleHashOrchard, 32> = Frontier::from_parts(Position::from(tree_in.position), leaf, tree_in.ommers.iter().map(|x| MerkleHashOrchard::from_bytes(&to_array(x.clone())).unwrap() ).collect()).unwrap();
+    let ct: CommitmentTree<MerkleHashOrchard, 32> = CommitmentTree::from_frontier(&frontier);
     let inc_wit = IncrementalWitness::from_tree(ct);
     let mut out_bytes: Vec<u8> = Vec::new();
     let result = write_incremental_witness(&inc_wit, &mut out_bytes);

src/C/Zcash.chs

@@ -255,7 +255,7 @@ import ZcashHaskell.Types
 #}
 
 {# fun unsafe rust_wrapper_read_orchard_witness as rustWrapperReadOrchardWitness
-     { toBorshVar* `BS.ByteString'&
+     { toBorshVar* `OrchardFrontier'&
      , getVarBuffer `Buffer HexString'&
      }
   -> `()'

src/ZcashHaskell/Orchard.hs

@@ -220,15 +220,13 @@ updateOrchardCommitmentTree tree cmx =
       rustWrapperReadOrchardCommitmentTree tree (hexBytes cmx)
 
 -- | Get the Orchard incremental witness from a commitment tree
-getOrchardWitness :: OrchardCommitmentTree -> Maybe OrchardWitness
+getOrchardWitness :: OrchardFrontier -> Maybe OrchardWitness
 getOrchardWitness tree =
   if BS.length (hexBytes wit) > 1
     then Just $ OrchardWitness wit
     else Nothing
   where
-    wit =
-      withPureBorshVarBuffer $
-      rustWrapperReadOrchardWitness (hexBytes $ orchTree tree)
+    wit = withPureBorshVarBuffer $ rustWrapperReadOrchardWitness tree
 
 -- | Get the Sapling note position from a witness
 getOrchardNotePosition :: OrchardWitness -> Integer