core/bitcoin: Support preauthorization in @with_keychain decorator.

core/src/apps/bitcoin/keychain.py

@@ -12,6 +12,8 @@ if False:
 
     from apps.common.keychain import Keychain, MsgOut, Handler
 
+    from .authorization import CoinJoinAuthorization
+
     class MsgWithCoinName(MessageType, Protocol):
         coin_name = ...  # type: Optional[str]
 
@@ -57,17 +59,20 @@ def get_namespaces_for_coin(coin: coininfo.CoinInfo):
     return namespaces
 
 
-async def get_keychain_for_coin(
-    ctx: wire.Context, coin_name: Optional[str]
-) -> Tuple[Keychain, coininfo.CoinInfo]:
+def get_coin_by_name(coin_name: Optional[str]) -> coininfo.CoinInfo:
     if coin_name is None:
         coin_name = "Bitcoin"
 
     try:
-        coin = coininfo.by_name(coin_name)
+        return coininfo.by_name(coin_name)
     except ValueError:
         raise wire.DataError("Unsupported coin type")
 
+
+async def get_keychain_for_coin(
+    ctx: wire.Context, coin_name: Optional[str]
+) -> Tuple[Keychain, coininfo.CoinInfo]:
+    coin = get_coin_by_name(coin_name)
     namespaces = get_namespaces_for_coin(coin)
     slip21_namespaces = [[b"SLIP-0019"]]
     keychain = await get_keychain(ctx, coin.curve_name, namespaces, slip21_namespaces)
@@ -75,9 +80,18 @@ async def get_keychain_for_coin(
 
 
 def with_keychain(func: HandlerWithCoinInfo[MsgIn, MsgOut]) -> Handler[MsgIn, MsgOut]:
-    async def wrapper(ctx: wire.Context, msg: MsgIn) -> MsgOut:
-        keychain, coin = await get_keychain_for_coin(ctx, msg.coin_name)
-        with keychain:
-            return await func(ctx, msg, keychain, coin)
+    async def wrapper(
+        ctx: wire.Context,
+        msg: MsgIn,
+        authorization: Optional[CoinJoinAuthorization] = None,
+    ) -> MsgOut:
+        if authorization:
+            keychain = authorization.keychain
+            coin = get_coin_by_name(msg.coin_name)
+            return await func(ctx, msg, keychain, coin, authorization)
+        else:
+            keychain, coin = await get_keychain_for_coin(ctx, msg.coin_name)
+            with keychain:
+                return await func(ctx, msg, keychain, coin)
 
     return wrapper