feat: implement Frontier for Sapling witnesses

Reviewed-on: https://git.vergara.tech///Vergara_Tech/zcash-haskell/pulls/96

librustzcash-wrapper/src/lib.rs

@@ -1369,6 +1369,31 @@ pub extern "C" fn rust_wrapper_bech32_encode(
     marshall_to_haskell_var(&string, out, out_len, RW);
 }
 
+#[no_mangle]
+pub extern "C" fn rust_wrapper_read_sapling_frontier(
+    tree: *const u8,
+    tree_len: usize,
+    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 comm_tree: CommitmentTree<Node, SAPLING_DEPTH> = read_commitment_tree(tree_reader).unwrap();
+    //let comm_tree: Frontier<MerkleHashOrchard, 32> = read_frontier_v1(tree_reader).unwrap();
+    let frontier: Frontier<Node, SAPLING_DEPTH> = comm_tree.to_frontier();
+    match frontier.value() {
+        Some(f1) => {
+            let (pos, leaf, omm) = f1.clone().into_parts();
+            let f = Hfrontier { position: <u64>::from(pos), leaf: Hhex { bytes: leaf.to_bytes().to_vec()}, ommers: omm.iter().map(|&x| x.to_bytes().to_vec()).collect()};
+            marshall_to_haskell_var(&f, out, out_len, RW);
+        },
+        None => {
+            let f0 = Hfrontier { position: 0, leaf: Hhex { bytes: vec![0]}, ommers: vec![vec![0]]};
+            marshall_to_haskell_var(&f0, out, out_len, RW);
+        }
+    }
+}
+
 #[no_mangle]
 pub extern "C" fn rust_wrapper_read_sapling_commitment_tree(
     tree: *const u8,
@@ -1687,21 +1712,31 @@ pub extern "C" fn rust_wrapper_create_transaction(
     build: bool,
     out: *mut u8,
     out_len: &mut usize){
-    let sap_wit_in: Vec<u8> = marshall_from_haskell_var(sap_wit, sap_wit_len, RW);
-    let sap_wit_reader = Cursor::new(sap_wit_in);
-    let sap_iw = read_commitment_tree::<Node, Cursor<Vec<u8>>, SAPLING_DEPTH>(sap_wit_reader);
-    let sap_anchor = match sap_iw {
-        Ok(s_iw) => {
-            Some(SaplingAnchor::from(s_iw.root()))
-        },
-        Err(_e) => {
+    //let sap_wit_in: Vec<u8> = marshall_from_haskell_var(sap_wit, sap_wit_len, RW);
+    //let sap_wit_reader = Cursor::new(sap_wit_in);
+    //let sap_iw = read_commitment_tree::<Node, Cursor<Vec<u8>>, SAPLING_DEPTH>(sap_wit_reader);
+    let sap_input: Vec<HsaplingInput> = marshall_from_haskell_var(s_input, s_input_len, RW);
+    let sap_anchor =
+        if sap_input.is_empty() {
             None
-        }
-    };
+        } else {
+            let si = &sap_input[0];
+            let swit_reader = Cursor::new(&si.iw);
+            let iw: IncrementalWitness<Node, SAPLING_DEPTH> = read_incremental_witness(swit_reader).unwrap();
+            Some(SaplingAnchor::from(iw.root()))
+        };
+    //let sap_anchor = match sap_iw {
+        //Ok(s_iw) => {
+            //Some(SaplingAnchor::from(s_iw.root()))
+        //},
+        //Err(_e) => {
+            //None
+        //}
+    //};
     //println!("{:?}", sap_anchor);
-    let orch_wit_in: Vec<u8> = marshall_from_haskell_var(orch_wit, orch_wit_len, RW);
-    let orch_wit_reader = Cursor::new(orch_wit_in);
-    let orch_iw = read_commitment_tree::<MerkleHashOrchard, Cursor<Vec<u8>>, 32>(orch_wit_reader);
+    //let orch_wit_in: Vec<u8> = marshall_from_haskell_var(orch_wit, orch_wit_len, RW);
+    //let orch_wit_reader = Cursor::new(orch_wit_in);
+    //let orch_iw = read_commitment_tree::<MerkleHashOrchard, Cursor<Vec<u8>>, 32>(orch_wit_reader);
     let orch_input: Vec<HorchardInput> = marshall_from_haskell_var(o_input, o_input_len, RW);
     //let orch_anchor = match orch_iw {
         //Ok(o_iw) => {
@@ -1746,7 +1781,6 @@ pub extern "C" fn rust_wrapper_create_transaction(
             }
         }
     }
-    let sap_input: Vec<HsaplingInput> = marshall_from_haskell_var(s_input, s_input_len, RW);
     for s_in in sap_input {
         if s_in.sk.len() > 1 {
             let sp_key = ExtendedSpendingKey::from_bytes(&s_in.sk);
@@ -1763,13 +1797,32 @@ pub extern "C" fn rust_wrapper_create_transaction(
                     let iw: IncrementalWitness<Node, SAPLING_DEPTH> = read_incremental_witness(wit_reader).unwrap();
                     let merkle_path = iw.path().unwrap();
                     if net {
-                        let _mb = main_builder.add_sapling_spend::<String>(&sk, note, merkle_path).unwrap();
+                        let mb = main_builder.add_sapling_spend::<String>(&sk, note, merkle_path);
+                        match mb {
+                            Ok(()) => {
+                                continue;
+                            },
+                            Err(_e) => {
+                                let x = Hhex {bytes: vec![5]};
+                                marshall_to_haskell_var(&x, out, out_len, RW);
+                            }
+                        }
                     } else {
-                        let _tb = test_builder.add_sapling_spend::<String>(&sk, note, merkle_path).unwrap();
+                        let tb = test_builder.add_sapling_spend::<String>(&sk, note, merkle_path);
+                        match tb {
+                            Ok(()) => {
+                                continue;
+                            },
+                            Err(_e) => {
+                                let x = Hhex {bytes: vec![5]};
+                                marshall_to_haskell_var(&x, out, out_len, RW);
+                            }
+                        }
                     }
                 },
                 Err(_e) => {
-                    continue;
+                    let x = Hhex {bytes: vec![5]};
+                    marshall_to_haskell_var(&x, out, out_len, RW);
                 }
             }
         }
@@ -1786,9 +1839,27 @@ pub extern "C" fn rust_wrapper_create_transaction(
             let iw: IncrementalWitness<MerkleHashOrchard, 32> = read_incremental_witness(wit_reader).unwrap();
             let merkle_path = OrchardMerklePath::from(iw.path().unwrap());
             if net {
-                let _mb = main_builder.add_orchard_spend::<String>(&sp_key, note, merkle_path).unwrap();
+                let mb = main_builder.add_orchard_spend::<String>(&sp_key, note, merkle_path);
+                match mb {
+                    Ok(()) => {
+                        continue;
+                    },
+                    Err(_e) => {
+                        let x = Hhex {bytes: vec![7]};
+                        marshall_to_haskell_var(&x, out, out_len, RW);
+                    }
+                }
             } else {
-                let _tb = test_builder.add_orchard_spend::<String>(&sp_key, note, merkle_path).unwrap();
+                let tb = test_builder.add_orchard_spend::<String>(&sp_key, note, merkle_path);
+                match tb {
+                    Ok(()) => {
+                        continue;
+                    },
+                    Err(_e) => {
+                        let x = Hhex {bytes: vec![7]};
+                        marshall_to_haskell_var(&x, out, out_len, RW);
+                    }
+                }
             }
         }
     }

src/C/Zcash.chs

@@ -204,9 +204,9 @@ import ZcashHaskell.Types
 #}
 
 {# fun unsafe rust_wrapper_read_sapling_commitment_tree as rustWrapperReadSaplingCommitmentTree
-     { toBorshVar* `BS.ByteString'&
+     { toBorshVar* `SaplingFrontier'&
      , toBorshVar* `BS.ByteString'&
-     , getVarBuffer `Buffer HexString'&
+     , getVarBuffer `Buffer SaplingFrontier'&
      }
   -> `()'
 #}
@@ -232,6 +232,13 @@ import ZcashHaskell.Types
   -> `()'
 #}
 
+{# fun unsafe rust_wrapper_read_sapling_frontier as rustWrapperReadSaplingFrontier
+     { toBorshVar* `BS.ByteString'&
+     , getVarBuffer `Buffer SaplingFrontier'&
+     }
+  -> `()'
+#}
+
 {# fun unsafe rust_wrapper_decode_sapling_address as rustWrapperDecodeSaplingAddress
      { toBorshVar* `BS.ByteString'&
      , getVarBuffer `Buffer (BS.ByteString)'&

src/ZcashHaskell/Sapling.hs

@@ -21,6 +21,7 @@ import C.Zcash
   ( rustWrapperDecodeSaplingAddress
   , rustWrapperIsShielded
   , rustWrapperReadSaplingCommitmentTree
+  , rustWrapperReadSaplingFrontier
   , rustWrapperReadSaplingPosition
   , rustWrapperReadSaplingWitness
   , rustWrapperSaplingCheck
@@ -184,21 +185,29 @@ genSaplingInternalAddress sk =
     res =
       withPureBorshVarBuffer (rustWrapperSaplingChgPaymentAddress $ getBytes sk)
 
--- | Update a Sapling commitment tree
-updateSaplingCommitmentTree ::
-     SaplingCommitmentTree -- ^ the base tree
-  -> HexString -- ^ the new note commitment
-  -> Maybe SaplingCommitmentTree
-updateSaplingCommitmentTree tree cmu =
-  if BS.length (hexBytes updatedTree) > 1
-    then Just $ SaplingCommitmentTree updatedTree
+getSaplingFrontier :: SaplingCommitmentTree -> Maybe SaplingFrontier
+getSaplingFrontier tree =
+  if sf_pos updatedTree > 1
+    then Just updatedTree
     else Nothing
   where
     updatedTree =
       withPureBorshVarBuffer $
-      rustWrapperReadSaplingCommitmentTree
-        (hexBytes $ sapTree tree)
-        (hexBytes cmu)
+      rustWrapperReadSaplingFrontier $ toBytes $ sapTree tree
+
+-- | Update a Sapling commitment tree
+updateSaplingCommitmentTree ::
+     SaplingFrontier -- ^ the base tree
+  -> HexString -- ^ the new note commitment
+  -> Maybe SaplingFrontier
+updateSaplingCommitmentTree tree cmu =
+  if sf_pos updatedTree > 1
+    then Just updatedTree
+    else Nothing
+  where
+    updatedTree =
+      withPureBorshVarBuffer $
+      rustWrapperReadSaplingCommitmentTree tree (hexBytes cmu)
 
 -- | Get the Sapling incremental witness from a commitment tree
 getSaplingWitness :: SaplingCommitmentTree -> Maybe SaplingWitness

src/ZcashHaskell/Types.hs

@@ -611,6 +611,15 @@ newtype SaplingCommitmentTree = SaplingCommitmentTree
   { sapTree :: HexString
   } deriving (Eq, Prelude.Show, Read)
 
+data SaplingFrontier = SaplingFrontier
+  { sf_pos :: !Int64
+  , sf_leaf :: !HexString
+  , sf_ommers :: ![BS.ByteString]
+  } deriving stock (Eq, Prelude.Show, GHC.Generic)
+    deriving anyclass (SOP.Generic, SOP.HasDatatypeInfo)
+    deriving anyclass (Data.Structured.Show)
+    deriving (BorshSize, ToBorsh, FromBorsh) via AsStruct SaplingFrontier
+
 -- | Type for a Sapling incremental witness
 newtype SaplingWitness = SaplingWitness
   { sapWit :: HexString