core/sign_tx: Add write_tx_output() to signer class and override it in Decred.

core/src/apps/wallet/sign_tx/bitcoin.py

@@ -226,7 +226,7 @@ class Bitcoin:
         elif not await helpers.confirm_output(txo, self.coin):
             raise SigningError(FailureType.ActionCancelled, "Output cancelled")
 
-        writers.write_tx_output(self.h_confirmed, txo_bin)
+        self.write_tx_output(self.h_confirmed, txo_bin)
         self.hash143_add_output(txo_bin)
         self.total_out += txo_bin.amount
 
@@ -345,8 +345,8 @@ class Bitcoin:
             txo = await helpers.request_tx_output(self.tx_req, i, self.coin)
             txo_bin.amount = txo.amount
             txo_bin.script_pubkey = self.output_derive_script(txo)
-            writers.write_tx_output(h_check, txo_bin)
-            writers.write_tx_output(h_sign, txo_bin)
+            self.write_tx_output(h_check, txo_bin)
+            self.write_tx_output(h_sign, txo_bin)
 
         writers.write_uint32(h_sign, self.tx.lock_time)
         writers.write_uint32(h_sign, self.get_hash_type())
@@ -376,7 +376,7 @@ class Bitcoin:
         txo_bin = TxOutputBinType()
         txo_bin.amount = txo.amount
         txo_bin.script_pubkey = self.output_derive_script(txo)
-        writers.write_tx_output(self.serialized_tx, txo_bin)
+        self.write_tx_output(self.serialized_tx, txo_bin)
 
     async def get_prevtx_output_value(self, prev_hash: bytes, prev_index: int) -> int:
         amount_out = 0  # output amount
@@ -407,7 +407,7 @@ class Bitcoin:
             txo_bin = await helpers.request_tx_output(
                 self.tx_req, i, self.coin, prev_hash
             )
-            writers.write_tx_output(txh, txo_bin)
+            self.write_tx_output(txh, txo_bin)
             if i == prev_index:
                 amount_out = txo_bin.amount
                 self.check_prevtx_output(txo_bin)
@@ -437,6 +437,9 @@ class Bitcoin:
     def write_tx_input(self, w: writers.Writer, txi: TxInputType) -> None:
         writers.write_tx_input(w, txi)
 
+    def write_tx_output(self, w: writers.Writer, txo_bin: TxOutputBinType) -> None:
+        writers.write_tx_output(w, txo_bin)
+
     def write_tx_header(
         self, w: writers.Writer, tx: Union[SignTx, TransactionType], has_segwit: bool
     ) -> None:

core/src/apps/wallet/sign_tx/bitcoinlike.py

@@ -44,7 +44,7 @@ class Bitcoinlike(Bitcoin):
         # serialize input with correct signature
         gc.collect()
         txi.script_sig = self.input_derive_script(txi, public_key, signature)
-        writers.write_tx_input(self.serialized_tx, txi)
+        self.write_tx_input(self.serialized_tx, txi)
         self.set_serialized_signature(i_sign, signature)
 
     async def sign_nonsegwit_input(self, i_sign: int) -> None:

core/src/apps/wallet/sign_tx/decred.py

@@ -68,7 +68,7 @@ class Decred(Bitcoin):
             )
         txo_bin.decred_script_version = txo.decred_script_version
         await super().confirm_output(i, txo, txo_bin)
-        writers.write_tx_output(self.serialized_tx, txo_bin)
+        self.write_tx_output(self.serialized_tx, txo_bin)
 
     async def step4_serialize_inputs(self) -> None:
         writers.write_varint(self.serialized_tx, self.tx.inputs_count)
@@ -154,11 +154,14 @@ class Decred(Bitcoin):
         writers.write_tx_input_decred(self.h_prefix, txi)
 
     def hash143_add_output(self, txo_bin: TxOutputBinType) -> None:
-        writers.write_tx_output(self.h_prefix, txo_bin)
+        writers.write_tx_output_decred(self.h_prefix, txo_bin)
 
     def write_tx_input(self, w: writers.Writer, txi: TxInputType) -> None:
         writers.write_tx_input_decred(w, txi)
 
+    def write_tx_output(self, w: writers.Writer, txo_bin: TxOutputBinType) -> None:
+        writers.write_tx_output_decred(w, txo_bin)
+
     def write_tx_header(
         self, w: writers.Writer, tx: Union[SignTx, TransactionType], has_segwit: bool
     ) -> None:

core/src/apps/wallet/sign_tx/writers.py

@@ -65,6 +65,11 @@ def write_tx_input_decred_witness(w: Writer, i: TxInputType) -> None:
 
 
 def write_tx_output(w: Writer, o: TxOutputBinType) -> None:
+    write_uint64(w, o.amount)
+    write_bytes_prefixed(w, o.script_pubkey)
+
+
+def write_tx_output_decred(w: Writer, o: TxOutputBinType) -> None:
     write_uint64(w, o.amount)
     if o.decred_script_version is not None:
         write_uint16(w, o.decred_script_version)