1#!/usr/bin/python3
2#
3# Copyright 2020, The Android Open Source Project
4#
5# Licensed under the Apache License, Version 2.0 (the "License");
6# you may not use this file except in compliance with the License.
7# You may obtain a copy of the License at
8#
9#     http://www.apache.org/licenses/LICENSE-2.0
10#
11# Unless required by applicable law or agreed to in writing, software
12# distributed under the License is distributed on an "AS IS" BASIS,
13# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
14# See the License for the specific language governing permissions and
15# limitations under the License.
16"""Converts a method to a descriptor or vice-versa.
17
18eg:
19
20% echo 'void myclass.foobar(long, java.lang.Object)' | method-to-descriptor.py
21Lmyclass;->foobar(jLjaga/lang/Object;)V
22% echo 'Lmyclass;->foobar(j)V' | method2descriptor.py -r
23void myclass.foobar(long)
24"""
25
26import argparse
27import sys
28
29
30def GetStdinLineIter():
31  """reads from stdin"""
32  return map(str.strip, sys.stdin)
33
34
35def readDescriptor(s):
36  """Reads a single descriptor and returns the string starting at the point after the descriptor"""
37  if s[0] == "[":
38    inner, rest = readDescriptor(s[1:])
39    return "[" + inner, rest
40  elif s[0] == "L":
41    type_end = s.index(";")
42    return s[:type_end + 1], s[type_end + 1:]
43  else:
44    assert s[0] in {"B", "C", "D", "F", "I", "J", "S", "Z", "V"}, s[0]
45    return s[0], s[1:]
46
47
48# Descriptor to name for basic types
49TYPE_MAP = {
50    "V": "void",
51    "B": "byte",
52    "C": "char",
53    "D": "double",
54    "F": "float",
55    "I": "int",
56    "J": "long",
57    "S": "short",
58    "Z": "boolean"
59}
60
61# Name to descriptor
62DESC_MAP = dict((y, x) for x, y in TYPE_MAP.items())
63
64def TypeDescriptorToName(desc):
65  """Turn a single type descirptor into a name"""
66  if desc[0] == "[":
67    inner = TypeDescriptorToName(desc[1:])
68    return inner + "[]"
69  elif desc[0] == "L":
70    assert desc[-1] == ";", desc
71    return desc[1:-1].replace("/", ".")
72  else:
73    return TYPE_MAP[desc]
74
75def DescriptorToName(desc):
76  """Turn a method descriptor into a name"""
77  class_name, rest = readDescriptor(desc)
78  assert rest[0:2] == "->", desc
79  rest = rest[2:]
80  args_start = rest.index("(")
81  func_name = rest[:args_start]
82  rest = rest[args_start + 1:]
83  args = []
84  while rest[0] != ")":
85    cur_arg, rest = readDescriptor(rest)
86    args.append(cur_arg)
87  rest = rest[1:]
88  return_type, rest = readDescriptor(rest)
89  assert rest.strip() == "", desc
90  return "{} {}.{}({})".format(
91      TypeDescriptorToName(return_type), TypeDescriptorToName(class_name),
92      func_name, ",".join(map(TypeDescriptorToName, args)))
93
94def SingleNameToDescriptor(name):
95  if name in DESC_MAP:
96    return DESC_MAP[name]
97  elif name.endswith("[]"):
98    return "[" + SingleNameToDescriptor(name[:-2])
99  elif name == "":
100    return ""
101  else:
102    return "L" + name.replace(".", "/") + ";"
103
104
105def NameToDescriptor(desc):
106  return_name = desc.split()[0]
107  name_and_args = desc.split()[1]
108  args_start = name_and_args.index("(")
109  names = name_and_args[0:args_start]
110  meth_split = names.rfind(".")
111  class_name = names[:meth_split]
112  meth_name = names[meth_split + 1:]
113  args = map(str.strip, name_and_args[args_start + 1:-1].split(","))
114  return "{}->{}({}){}".format(
115      SingleNameToDescriptor(class_name), meth_name,
116      "".join(map(SingleNameToDescriptor, args)),
117      SingleNameToDescriptor(return_name))
118
119
120def main():
121  parser = argparse.ArgumentParser(
122      "method-to-descriptor.py",
123      description="Convert a java method-name/stream into it's descriptor or vice-versa."
124  )
125  parser.add_argument(
126      "-r",
127      "--reverse",
128      dest="reverse",
129      action="store_true",
130      default=False,
131      help="reverse. Go from descriptor to method-declaration")
132  parser.add_argument("method", help="what to change", nargs="*")
133  args = parser.parse_args()
134  if args.method != []:
135    inputs = iter(args.method)
136  else:
137    inputs = GetStdinLineIter()
138  for name in inputs:
139    if args.reverse:
140      print(DescriptorToName(name))
141    else:
142      print(NameToDescriptor(name))
143
144
145if __name__ == "__main__":
146  main()
147