protobuf: improve prettyprint formatting

trezorlib/protobuf.py

@@ -41,7 +41,7 @@ required:
 
 import binascii
 from io import BytesIO
-from typing import Any
+from typing import Any, Optional
 
 _UVARINT_BUFFER = bytearray(1)
 
@@ -348,37 +348,63 @@ def dump_message(writer, msg):
                 raise TypeError
 
 
-def format_message(pb: MessageType, indent: int=0, sep: str= ' ' * 4) -> str:
+def format_message(pb: MessageType,
+                   indent: int = 0,
+                   sep: str = ' ' * 4,
+                   truncate_after: Optional[int] = 256,
+                   truncate_to: Optional[int] = 64,
+                   collapse_cointypes: bool = False) -> str:
+
+    def mostly_printable(bytes):
+        if not bytes:
+            return True
+        printable = sum(1 for byte in bytes if 0x20 <= byte <= 0x7e)
+        return printable / len(bytes) > 0.8
+
     def pformat_value(value: Any, indent: int) -> str:
         level = sep * indent
         leadin = sep * (indent + 1)
         if isinstance(value, MessageType):
             return format_message(value, indent, sep)
         if isinstance(value, list):
-            lines = []
+            # short list of simple values
-            lines.append('[')
+            if not value or not isinstance(value[0], MessageType):
-            lines += [leadin + pformat_value(x, indent + 1) + ',' for x in value]
+                return repr(value)
-            lines.append(level + ']')
+
+            # long list, one line per entry
+            lines = ['[', level + ']']
+            lines[1:1] = [leadin + pformat_value(x, indent + 1) + ',' for x in value]
             return '\n'.join(lines)
         if isinstance(value, dict):
-            lines = []
+            lines = ['{']
-            lines.append('{')
             for key, val in sorted(value.items()):
                 if val is None or val == []:
                     continue
-                if key == 'address_n' and isinstance(val, list):
-                    lines.append(leadin + key + ': ' + repr(val) + ',')
-                else:
                 lines.append(leadin + key + ': ' + pformat_value(val, indent + 1) + ',')
             lines.append(level + '}')
             return '\n'.join(lines)
-        if isinstance(value, bytearray):
+        if isinstance(value, (bytes, bytearray)):
-            return 'bytearray(0x{})'.format(binascii.hexlify(value).decode('ascii'))
+            length = len(value)
+            suffix = ''
+            if truncate_after and length > truncate_after:
+                suffix = '...'
+                value = value[:truncate_to or 0]
+            if mostly_printable(value):
+                output = repr(value)
+            else:
+                output = '0x' + binascii.hexlify(value).decode('ascii')
+            return '{} bytes {}{}'.format(length, output, suffix)
 
         return repr(value)
 
+    from .messages import Features
+    pb_dict = pb.__dict__.copy()
+    if collapse_cointypes and isinstance(pb, Features):
+        del pb_dict['coins']
+        pb_dict['coins (shortened)'] = ' '.join(coin.coin_shortcut for coin in pb.coins)
+
     return '{name} ({size} bytes) {content}'.format(
         name=pb.__class__.__name__,
         size=pb.ByteSize(),
-        content=pformat_value(pb.__dict__, indent)
+        content=pformat_value(pb_dict, indent)
     )