refactor(core): Replace Bitcoin signing progress functions with a class.

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

@@ -91,6 +91,6 @@ async def sign_tx(
             res = await ctx.call(req, request_class)
         elif isinstance(req, helpers.UiConfirm):
             res = await req.confirm_dialog(ctx)
-            progress.report_init()
+            progress.progress.report_init()
         else:
             raise TypeError("Invalid signing instruction")

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

@@ -19,7 +19,8 @@ from ..common import (
 )
 from ..ownership import verify_nonownership
 from ..verification import SignatureVerifier
-from . import approvers, helpers, progress
+from . import approvers, helpers
+from .progress import progress
 from .sig_hasher import BitcoinSigHasher
 from .tx_info import OriginalTxInfo, TxInfo
 

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

@@ -12,9 +12,10 @@ from apps.common.writers import write_compact_size
 
 from .. import multisig, scripts_decred, writers
 from ..common import SigHashType, ecdsa_hash_pubkey, ecdsa_sign
-from . import approvers, helpers, progress
+from . import approvers, helpers
 from .approvers import BasicApprover
 from .bitcoin import Bitcoin
+from .progress import progress
 
 DECRED_SERIALIZE_FULL = const(0 << 16)
 DECRED_SERIALIZE_NO_WITNESS = const(1 << 16)

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

@@ -12,25 +12,32 @@ if TYPE_CHECKING:
 # the input, prevtx metadata, prevtx input, prevtx output, prevtx change-output
 _PREV_TX_MULTIPLIER = 5
 
-_progress = 0
-_steps = 0
-_signing = False
-_prev_tx_step = 0
 
+class Progress:
+    def __init__(self):
+        self.progress = 0
+        self.steps = 0
+        self.signing = False
 
-def init(tx: SignTx) -> None:
-    global _progress, _steps, _signing
-    _progress = 0
-    _signing = False
+        # We don't know how long it will take to fetch the previous transactions,
+        # so for each one we reserve _PREV_TX_MULTIPLIER steps in the signing
+        # progress. Once we fetch a prev_tx's metadata, we subdivide the reserved
+        # space and then prev_tx_step represents the progress of fetching one
+        # prev_tx input or output in the overall signing progress.
+        self.prev_tx_step = 0
+
+    def init(self, tx: SignTx) -> None:
+        self.progress = 0
+        self.signing = False
 
         # Step 1 and 2 - load inputs and outputs
-    _steps = tx.inputs_count + tx.outputs_count
-
-    report_init()
-    report()
+        self.steps = tx.inputs_count + tx.outputs_count
 
+        self.report_init()
+        self.report()
 
     def init_signing(
+        self,
         external: int,
         segwit: int,
         taproot_only: bool,
@@ -41,26 +48,27 @@ def init_signing(
         orig_txs: list[OriginalTxInfo],
     ) -> None:
         if __debug__:
-        assert_finished()
+            self.assert_finished()
 
-    global _progress, _steps, _signing
-    _progress = 0
-    _steps = 0
-    _signing = True
+        self.progress = 0
+        self.steps = 0
+        self.signing = True
 
         # Step 3 - verify inputs
         if taproot_only or (coin.overwintered and tx.version == 5):
             if has_presigned:
-            _steps += external
+                self.steps += external
         else:
-        _steps = tx.inputs_count * _PREV_TX_MULTIPLIER
+            self.steps = tx.inputs_count * _PREV_TX_MULTIPLIER
 
         for orig in orig_txs:
-        _steps += orig.tx.inputs_count
+            self.steps += orig.tx.inputs_count
 
         # Steps 3 and 4 - get_legacy_tx_digest() for each legacy input.
         if not (coin.force_bip143 or coin.overwintered or coin.decred):
-        _steps += (tx.inputs_count - segwit) * (tx.inputs_count + tx.outputs_count)
+            self.steps += (tx.inputs_count - segwit) * (
+                tx.inputs_count + tx.outputs_count
+            )
 
             if segwit != tx.inputs_count:
                 # The transaction has a legacy input.
@@ -68,67 +76,62 @@ def init_signing(
                 # Simplification: We assume that all original transaction inputs
                 # are legacy, since mixed script types are not supported in Suite.
                 for orig in orig_txs:
-                _steps += orig.tx.inputs_count * (
+                    self.steps += orig.tx.inputs_count * (
                         orig.tx.inputs_count + orig.tx.outputs_count
                     )
 
         # Steps 4 and 6 - serialize and sign inputs
         if serialize:
-        _steps += tx.inputs_count + segwit
+            self.steps += tx.inputs_count + segwit
         else:
-        _steps += tx.inputs_count - external
+            self.steps += tx.inputs_count - external
 
         # Step 5 - serialize outputs
         if serialize and not coin.decred:
-        _steps += tx.outputs_count
+            self.steps += tx.outputs_count
 
-    report_init()
-    report()
+        self.report_init()
+        self.report()
 
+    def init_prev_tx(self, inputs: int, outputs: int) -> None:
+        self.prev_tx_step = _PREV_TX_MULTIPLIER / (inputs + outputs)
 
-def init_prev_tx(inputs: int, outputs: int) -> None:
-    global _prev_tx_step
-    _prev_tx_step = _PREV_TX_MULTIPLIER / (inputs + outputs)
+    def advance(self) -> None:
+        self.progress += 1
+        self.report()
 
+    def advance_prev_tx(self) -> None:
+        self.progress += self.prev_tx_step
+        self.report()
 
-def advance() -> None:
-    global _progress
-    _progress += 1
-    report()
-
-
-def advance_prev_tx() -> None:
-    global _progress
-    _progress += _prev_tx_step
-    report()
-
-
-def report_init() -> None:
+    def report_init(self) -> None:
         from trezor import workflow
 
         workflow.close_others()
         ui.display.clear()
-    if _signing:
+        if self.signing:
             ui.header("Signing transaction")
         else:
             ui.header("Loading transaction")
 
-
-def report() -> None:
+    def report(self) -> None:
         from trezor import utils
 
         if utils.DISABLE_ANIMATION:
             return
-    p = int(1000 * _progress / _steps)
+        p = int(1000 * self.progress / self.steps)
         ui.display.loader(p, False, 18, ui.WHITE, ui.BG)
 
-
     if __debug__:
 
-    def assert_finished() -> None:
-        if abs(_progress - _steps) > 0.5:
-            operation = "signing" if _signing else "loading"
+        def assert_finished(self) -> None:
+            if abs(self.progress - self.steps) > 0.5:
                 from trezor import wire
+
+                operation = "signing" if self.signing else "loading"
                 raise wire.FirmwareError(
-                f"Transaction {operation} progress finished at {_progress}/{_steps}."
+                    f"Transaction {operation} progress finished at {self.progress}/{self.steps}."
                 )
+
+
+progress = Progress()