Lib/pyclbr.py

   1 """Parse a Python module and describe its classes and methods.
   2
   3 Parse enough of a Python file to recognize imports and class and
   4 method definitions, and to find out the superclasses of a class.
   5
   6 The interface consists of a single function:
   7         readmodule_ex(module [, path])
   8 where module is the name of a Python module, and path is an optional
   9 list of directories where the module is to be searched.  If present,
  10 path is prepended to the system search path sys.path.  The return
  11 value is a dictionary.  The keys of the dictionary are the names of
  12 the classes defined in the module (including classes that are defined
  13 via the from XXX import YYY construct).  The values are class
  14 instances of the class Class defined here.  One special key/value pair
  15 is present for packages: the key '__path__' has a list as its value
  16 which contains the package search path.
  17
  18 A class is described by the class Class in this module.  Instances
  19 of this class have the following instance variables:
  20         module -- the module name
  21         name -- the name of the class
  22         super -- a list of super classes (Class instances)
  23         methods -- a dictionary of methods
  24         file -- the file in which the class was defined
  25         lineno -- the line in the file on which the class statement occurred
  26 The dictionary of methods uses the method names as keys and the line
  27 numbers on which the method was defined as values.
  28 If the name of a super class is not recognized, the corresponding
  29 entry in the list of super classes is not a class instance but a
  30 string giving the name of the super class.  Since import statements
  31 are recognized and imported modules are scanned as well, this
  32 shouldn't happen often.
  33
  34 A function is described by the class Function in this module.
  35 Instances of this class have the following instance variables:
  36         module -- the module name
  37         name -- the name of the class
  38         file -- the file in which the class was defined
  39         lineno -- the line in the file on which the class statement occurred
  40 """
  41
  42 import sys
  43 import imp
  44 import tokenize
  45 from token import NAME, DEDENT, OP
  46 from operator import itemgetter
  47
  48 __all__ = ["readmodule", "readmodule_ex", "Class", "Function"]
  49
  50 _modules = {}                           # cache of modules we've seen
  51
  52 # each Python class is represented by an instance of this class
  53 class Class:
  54     '''Class to represent a Python class.'''
  55     def __init__(self, module, name, super, file, lineno):
  56         self.module = module
  57         self.name = name
  58         if super is None:
  59             super = []
  60         self.super = super
  61         self.methods = {}
  62         self.file = file
  63         self.lineno = lineno
  64
  65     def _addmethod(self, name, lineno):
  66         self.methods[name] = lineno
  67
  68 class Function:
  69     '''Class to represent a top-level Python function'''
  70     def __init__(self, module, name, file, lineno):
  71         self.module = module
  72         self.name = name
  73         self.file = file
  74         self.lineno = lineno
  75
  76 def readmodule(module, path=None):
  77     '''Backwards compatible interface.
  78
  79     Call readmodule_ex() and then only keep Class objects from the
  80     resulting dictionary.'''
  81
  82     res = {}
  83     for key, value in _readmodule(module, path or []).items():
  84         if isinstance(value, Class):
  85             res[key] = value
  86     return res
  87
  88 def readmodule_ex(module, path=None):
  89     '''Read a module file and return a dictionary of classes.
  90
  91     Search for MODULE in PATH and sys.path, read and parse the
  92     module and return a dictionary with one entry for each class
  93     found in the module.
  94     '''
  95     return _readmodule(module, path or [])
  96
  97 def _readmodule(module, path, inpackage=None):
  98     '''Do the hard work for readmodule[_ex].
  99
 100     If INPACKAGE is given, it must be the dotted name of the package in
 101     which we are searching for a submodule, and then PATH must be the
 102     package search path; otherwise, we are searching for a top-level
 103     module, and PATH is combined with sys.path.
 104     '''
 105     # Compute the full module name (prepending inpackage if set)
 106     if inpackage is not None:
 107         fullmodule = "%s.%s" % (inpackage, module)
 108     else:
 109         fullmodule = module
 110
 111     # Check in the cache
 112     if fullmodule in _modules:
 113         return _modules[fullmodule]
 114
 115     # Initialize the dict for this module's contents
 116     dict = {}
 117
 118     # Check if it is a built-in module; we don't do much for these
 119     if module in sys.builtin_module_names and inpackage is None:
 120         _modules[module] = dict
 121         return dict
 122
 123     # Check for a dotted module name
 124     i = module.rfind('.')
 125     if i >= 0:
 126         package = module[:i]
 127         submodule = module[i+1:]
 128         parent = _readmodule(package, path, inpackage)
 129         if inpackage is not None:
 130             package = "%s.%s" % (inpackage, package)
 131         return _readmodule(submodule, parent['__path__'], package)
 132
 133     # Search the path for the module
 134     f = None
 135     if inpackage is not None:
 136         f, fname, (_s, _m, ty) = imp.find_module(module, path)
 137     else:
 138         f, fname, (_s, _m, ty) = imp.find_module(module, path + sys.path)
 139     if ty == imp.PKG_DIRECTORY:
 140         dict['__path__'] = [fname]
 141         path = [fname] + path
 142         f, fname, (_s, _m, ty) = imp.find_module('__init__', [fname])
 143     _modules[fullmodule] = dict
 144     if ty != imp.PY_SOURCE:
 145         # not Python source, can't do anything with this module
 146         f.close()
 147         return dict
 148
 149     stack = [] # stack of (class, indent) pairs
 150
 151     g = tokenize.generate_tokens(f.readline)
 152     try:
 153         for tokentype, token, start, _end, _line in g:
 154             if tokentype == DEDENT:
 155                 lineno, thisindent = start
 156                 # close nested classes and defs
 157                 while stack and stack[-1][1] >= thisindent:
 158                     del stack[-1]
 159             elif token == 'def':
 160                 lineno, thisindent = start
 161                 # close previous nested classes and defs
 162                 while stack and stack[-1][1] >= thisindent:
 163                     del stack[-1]
 164                 tokentype, meth_name, start = next(g)[0:3]
 165                 if tokentype != NAME:
 166                     continue # Syntax error
 167                 if stack:
 168                     cur_class = stack[-1][0]
 169                     if isinstance(cur_class, Class):
 170                         # it's a method
 171                         cur_class._addmethod(meth_name, lineno)
 172                     # else it's a nested def
 173                 else:
 174                     # it's a function
 175                     dict[meth_name] = Function(fullmodule, meth_name,
 176                                                fname, lineno)
 177                 stack.append((None, thisindent)) # Marker for nested fns
 178             elif token == 'class':
 179                 lineno, thisindent = start
 180                 # close previous nested classes and defs
 181                 while stack and stack[-1][1] >= thisindent:
 182                     del stack[-1]
 183                 tokentype, class_name, start = next(g)[0:3]
 184                 if tokentype != NAME:
 185                     continue # Syntax error
 186                 # parse what follows the class name
 187                 tokentype, token, start = next(g)[0:3]
 188                 inherit = None
 189                 if token == '(':
 190                     names = [] # List of superclasses
 191                     # there's a list of superclasses
 192                     level = 1
 193                     super = [] # Tokens making up current superclass
 194                     while True:
 195                         tokentype, token, start = next(g)[0:3]
 196                         if token in (')', ',') and level == 1:
 197                             n = "".join(super)
 198                             if n in dict:
 199                                 # we know this super class
 200                                 n = dict[n]
 201                             else:
 202                                 c = n.split('.')
 203                                 if len(c) > 1:
 204                                     # super class is of the form
 205                                     # module.class: look in module for
 206                                     # class
 207                                     m = c[-2]
 208                                     c = c[-1]
 209                                     if m in _modules:
 210                                         d = _modules[m]
 211                                         if c in d:
 212                                             n = d[c]
 213                             names.append(n)
 214                             super = []
 215                         if token == '(':
 216                             level += 1
 217                         elif token == ')':
 218                             level -= 1
 219                             if level == 0:
 220                                 break
 221                         elif token == ',' and level == 1:
 222                             pass
 223                         # only use NAME and OP (== dot) tokens for type name
 224                         elif tokentype in (NAME, OP) and level == 1:
 225                             super.append(token)
 226                         # expressions in the base list are not supported
 227                     inherit = names
 228                 cur_class = Class(fullmodule, class_name, inherit,
 229                                   fname, lineno)
 230                 if not stack:
 231                     dict[class_name] = cur_class
 232                 stack.append((cur_class, thisindent))
 233             elif token == 'import' and start[1] == 0:
 234                 modules = _getnamelist(g)
 235                 for mod, _mod2 in modules:
 236                     try:
 237                         # Recursively read the imported module
 238                         if inpackage is None:
 239                             _readmodule(mod, path)
 240                         else:
 241                             try:
 242                                 _readmodule(mod, path, inpackage)
 243                             except ImportError:
 244                                 _readmodule(mod, [])
 245                     except:
 246                         # If we can't find or parse the imported module,
 247                         # too bad -- don't die here.
 248                         pass
 249             elif token == 'from' and start[1] == 0:
 250                 mod, token = _getname(g)
 251                 if not mod or token != "import":
 252                     continue
 253                 names = _getnamelist(g)
 254                 try:
 255                     # Recursively read the imported module
 256                     d = _readmodule(mod, path, inpackage)
 257                 except:
 258                     # If we can't find or parse the imported module,
 259                     # too bad -- don't die here.
 260                     continue
 261                 # add any classes that were defined in the imported module
 262                 # to our name space if they were mentioned in the list
 263                 for n, n2 in names:
 264                     if n in d:
 265                         dict[n2 or n] = d[n]
 266                     elif n == '*':
 267                         # don't add names that start with _
 268                         for n in d:
 269                             if n[0] != '_':
 270                                 dict[n] = d[n]
 271     except StopIteration:
 272         pass
 273
 274     f.close()
 275     return dict
 276
 277 def _getnamelist(g):
 278     # Helper to get a comma-separated list of dotted names plus 'as'
 279     # clauses.  Return a list of pairs (name, name2) where name2 is
 280     # the 'as' name, or None if there is no 'as' clause.
 281     names = []
 282     while True:
 283         name, token = _getname(g)
 284         if not name:
 285             break
 286         if token == 'as':
 287             name2, token = _getname(g)
 288         else:
 289             name2 = None
 290         names.append((name, name2))
 291         while token != "," and "\n" not in token:
 292             token = next(g)[1]
 293         if token != ",":
 294             break
 295     return names
 296
 297 def _getname(g):
 298     # Helper to get a dotted name, return a pair (name, token) where
 299     # name is the dotted name, or None if there was no dotted name,
 300     # and token is the next input token.
 301     parts = []
 302     tokentype, token = next(g)[0:2]
 303     if tokentype != NAME and token != '*':
 304         return (None, token)
 305     parts.append(token)
 306     while True:
 307         tokentype, token = next(g)[0:2]
 308         if token != '.':
 309             break
 310         tokentype, token = next(g)[0:2]
 311         if tokentype != NAME:
 312             break
 313         parts.append(token)
 314     return (".".join(parts), token)
 315
 316 def _main():
 317     # Main program for testing.
 318     import os
 319     mod = sys.argv[1]
 320     if os.path.exists(mod):
 321         path = [os.path.dirname(mod)]
 322         mod = os.path.basename(mod)
 323         if mod.lower().endswith(".py"):
 324             mod = mod[:-3]
 325     else:
 326         path = []
 327     dict = readmodule_ex(mod, path)
 328     objs = dict.values()
 329     objs.sort(key=lambda a: getattr(a, 'lineno', 0))
 330     for obj in objs:
 331         if isinstance(obj, Class):
 332             print("class", obj.name, obj.super, obj.lineno)
 333             methods = sorted(obj.methods.items(), key=itemgetter(1))
 334             for name, lineno in methods:
 335                 if name != "__path__":
 336                     print("  def", name, lineno)
 337         elif isinstance(obj, Function):
 338             print("def", obj.name, obj.lineno)
 339
 340 if __name__ == "__main__":
 341     _main()