Refactor __main__.main into smaller functions

rsrcfork/__main__.py

@@ -214,7 +214,7 @@ def _describe_resource(res: api.Resource, *, include_type: bool, decompress: boo
 		desc = f"'{restype}' {desc}"
 	return desc
 
-def main():
+def _parse_args() -> argparse.Namespace:
 	ap = argparse.ArgumentParser(
 		add_help=False,
 		fromfile_prefix_chars="@",
@@ -249,82 +249,62 @@ def main():
 	ap.add_argument("filter", nargs="*", help="One or more filters to select which resources to display, or omit to show an overview of all resources")
 	
 	ns = ap.parse_args()
+	return ns
 
-	if ns.file == "-":
+def _show_header_data(data: bytes, *, format: str) -> None:
-		if ns.fork is not None:
+	if format == "dump":
-			print("Cannot specify an explicit fork when reading from stdin", file=sys.stderr)
-			sys.exit(1)
-		
-		rf = api.ResourceFile(sys.stdin.buffer)
-	else:
-		rf = api.ResourceFile.open(ns.file, fork=ns.fork)
-	
-	with rf:
-		if ns.header_system or ns.header_application:
-			if ns.header_system:
-				data = rf.header_system_data
-			else:
-				data = rf.header_application_data
-			
-			if ns.format == "dump":
 		_hexdump(data)
-			elif ns.format == "hex":
+	elif format == "hex":
 		_raw_hexdump(data)
-			elif ns.format == "raw":
+	elif format == "raw":
 		sys.stdout.buffer.write(data)
-			elif ns.format == "derez":
+	elif format == "derez":
 		print("Cannot output file header data in derez format", file=sys.stderr)
 		sys.exit(1)
 	else:
-				raise ValueError(f"Unhandled output format: {ns.format}")
+		raise ValueError(f"Unhandled output format: {format}")
-		elif ns.filter or ns.all:
-			if ns.filter:
-				resources = _filter_resources(rf, ns.filter)
-			else:
-				resources = []
-				for reses in rf.values():
-					resources.extend(reses.values())
 
+def _show_filtered_resources(resources: typing.Sequence[api.Resource], format: str, decompress: bool) -> None:
 	if not resources:
-				if ns.format == "dump":
+		if format == "dump":
 			print("No resources matched the filter")
-				elif ns.format in ("hex", "raw"):
+		elif format in ("hex", "raw"):
 			print("No resources matched the filter", file=sys.stderr)
 			sys.exit(1)
-				elif ns.format == "derez":
+		elif format == "derez":
 			print("/* No resources matched the filter */")
 		else:
-					raise AssertionError(f"Unhandled output format: {ns.format}")
+			raise AssertionError(f"Unhandled output format: {format}")
-			elif ns.format in ("hex", "raw") and len(resources) != 1:
+	elif format in ("hex", "raw") and len(resources) != 1:
-				print(f"Format {ns.format} can only output a single resource, but the filter matched {len(resources)} resources", file=sys.stderr)
+		print(f"Format {format} can only output a single resource, but the filter matched {len(resources)} resources", file=sys.stderr)
 		sys.exit(1)
 	
 	for res in resources:
-				if ns.decompress:
+		if decompress:
 			data = res.data
 		else:
 			data = res.data_raw
 		
-				if ns.format == "dump":
+		if format == "dump":
 			# Human-readable info and hex dump
-					desc = _describe_resource(res, include_type=True, decompress=ns.decompress)
+			desc = _describe_resource(res, include_type=True, decompress=decompress)
 			print(f"Resource {desc}:")
 			_hexdump(data)
 			print()
-				elif ns.format == "hex":
+		elif format == "hex":
 			# Data only as hex
 			
 			_raw_hexdump(data)
-				elif ns.format == "raw":
+		elif format == "raw":
 			# Data only as raw bytes
 			
 			sys.stdout.buffer.write(data)
-				elif ns.format == "derez":
+		elif format == "derez":
 			# Like DeRez with no resource definitions
 			
 			attrs = list(_decompose_flags(res.attributes))
 			
-					if ns.decompress and api.ResourceAttrs.resCompressed in attrs:
+			if decompress and api.ResourceAttrs.resCompressed in attrs:
 				attrs.remove(api.ResourceAttrs.resCompressed)
 				attrs_comment = " /* was compressed */"
 			else:
@@ -363,8 +343,9 @@ def main():
 			print("};")
 			print()
 		else:
-					raise ValueError(f"Unhandled output format: {ns.format}")
+			raise ValueError(f"Unhandled output format: {format}")
-		else:
+
+def _list_resource_file(rf: api.ResourceFile, *, decompress: bool) -> None:
 	if rf.header_system_data != bytes(len(rf.header_system_data)):
 		print("Header system data:")
 		_hexdump(rf.header_system_data)
@@ -383,11 +364,43 @@ def main():
 			restype = _bytes_escape(typecode, quote="'")
 			print(f"'{restype}': {len(resources)} resources:")
 			for resid, res in rf[typecode].items():
-						print(_describe_resource(res, include_type=False, decompress=ns.decompress))
+				print(_describe_resource(res, include_type=False, decompress=decompress))
 			print()
 	else:
 		print("No resource types (empty resource file)")
 
+def main():
+	ns = _parse_args()
+	
+	if ns.file == "-":
+		if ns.fork is not None:
+			print("Cannot specify an explicit fork when reading from stdin", file=sys.stderr)
+			sys.exit(1)
+		
+		rf = api.ResourceFile(sys.stdin.buffer)
+	else:
+		rf = api.ResourceFile.open(ns.file, fork=ns.fork)
+	
+	with rf:
+		if ns.header_system or ns.header_application:
+			if ns.header_system:
+				data = rf.header_system_data
+			else:
+				data = rf.header_application_data
+			
+			_show_header_data(data, format=ns.format)
+		elif ns.filter or ns.all:
+			if ns.filter:
+				resources = _filter_resources(rf, ns.filter)
+			else:
+				resources = []
+				for reses in rf.values():
+					resources.extend(reses.values())
+			
+			_show_filtered_resources(resources, format=ns.format, decompress=ns.decompress)
+		else:
+			_list_resource_file(rf, decompress=ns.decompress)
+	
 	sys.exit(0)
 
 if __name__ == "__main__":