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- """Parse a Python module and describe its classes and functions.
- Parse enough of a Python file to recognize imports and class and
- function definitions, and to find out the superclasses of a class.
- The interface consists of a single function:
- readmodule_ex(module, path=None)
- where module is the name of a Python module, and path is an optional
- list of directories where the module is to be searched. If present,
- path is prepended to the system search path sys.path. The return value
- is a dictionary. The keys of the dictionary are the names of the
- classes and functions defined in the module (including classes that are
- defined via the from XXX import YYY construct). The values are
- instances of classes Class and Function. One special key/value pair is
- present for packages: the key '__path__' has a list as its value which
- contains the package search path.
- Classes and Functions have a common superclass: _Object. Every instance
- has the following attributes:
- module -- name of the module;
- name -- name of the object;
- file -- file in which the object is defined;
- lineno -- line in the file where the object's definition starts;
- parent -- parent of this object, if any;
- children -- nested objects contained in this object.
- The 'children' attribute is a dictionary mapping names to objects.
- Instances of Function describe functions with the attributes from _Object.
- Instances of Class describe classes with the attributes from _Object,
- plus the following:
- super -- list of super classes (Class instances if possible);
- methods -- mapping of method names to beginning line numbers.
- If the name of a super class is not recognized, the corresponding
- entry in the list of super classes is not a class instance but a
- string giving the name of the super class. Since import statements
- are recognized and imported modules are scanned as well, this
- shouldn't happen often.
- """
- import io
- import sys
- import importlib.util
- import tokenize
- from token import NAME, DEDENT, OP
- __all__ = ["readmodule", "readmodule_ex", "Class", "Function"]
- _modules = {} # Initialize cache of modules we've seen.
- class _Object:
- "Information about Python class or function."
- def __init__(self, module, name, file, lineno, parent):
- self.module = module
- self.name = name
- self.file = file
- self.lineno = lineno
- self.parent = parent
- self.children = {}
- def _addchild(self, name, obj):
- self.children[name] = obj
- class Function(_Object):
- "Information about a Python function, including methods."
- def __init__(self, module, name, file, lineno, parent=None):
- _Object.__init__(self, module, name, file, lineno, parent)
- class Class(_Object):
- "Information about a Python class."
- def __init__(self, module, name, super, file, lineno, parent=None):
- _Object.__init__(self, module, name, file, lineno, parent)
- self.super = [] if super is None else super
- self.methods = {}
- def _addmethod(self, name, lineno):
- self.methods[name] = lineno
- def _nest_function(ob, func_name, lineno):
- "Return a Function after nesting within ob."
- newfunc = Function(ob.module, func_name, ob.file, lineno, ob)
- ob._addchild(func_name, newfunc)
- if isinstance(ob, Class):
- ob._addmethod(func_name, lineno)
- return newfunc
- def _nest_class(ob, class_name, lineno, super=None):
- "Return a Class after nesting within ob."
- newclass = Class(ob.module, class_name, super, ob.file, lineno, ob)
- ob._addchild(class_name, newclass)
- return newclass
- def readmodule(module, path=None):
- """Return Class objects for the top-level classes in module.
- This is the original interface, before Functions were added.
- """
- res = {}
- for key, value in _readmodule(module, path or []).items():
- if isinstance(value, Class):
- res[key] = value
- return res
- def readmodule_ex(module, path=None):
- """Return a dictionary with all functions and classes in module.
- Search for module in PATH + sys.path.
- If possible, include imported superclasses.
- Do this by reading source, without importing (and executing) it.
- """
- return _readmodule(module, path or [])
- def _readmodule(module, path, inpackage=None):
- """Do the hard work for readmodule[_ex].
- If inpackage is given, it must be the dotted name of the package in
- which we are searching for a submodule, and then PATH must be the
- package search path; otherwise, we are searching for a top-level
- module, and path is combined with sys.path.
- """
- # Compute the full module name (prepending inpackage if set).
- if inpackage is not None:
- fullmodule = "%s.%s" % (inpackage, module)
- else:
- fullmodule = module
- # Check in the cache.
- if fullmodule in _modules:
- return _modules[fullmodule]
- # Initialize the dict for this module's contents.
- tree = {}
- # Check if it is a built-in module; we don't do much for these.
- if module in sys.builtin_module_names and inpackage is None:
- _modules[module] = tree
- return tree
- # Check for a dotted module name.
- i = module.rfind('.')
- if i >= 0:
- package = module[:i]
- submodule = module[i+1:]
- parent = _readmodule(package, path, inpackage)
- if inpackage is not None:
- package = "%s.%s" % (inpackage, package)
- if not '__path__' in parent:
- raise ImportError('No package named {}'.format(package))
- return _readmodule(submodule, parent['__path__'], package)
- # Search the path for the module.
- f = None
- if inpackage is not None:
- search_path = path
- else:
- search_path = path + sys.path
- spec = importlib.util._find_spec_from_path(fullmodule, search_path)
- if spec is None:
- raise ModuleNotFoundError(f"no module named {fullmodule!r}", name=fullmodule)
- _modules[fullmodule] = tree
- # Is module a package?
- if spec.submodule_search_locations is not None:
- tree['__path__'] = spec.submodule_search_locations
- try:
- source = spec.loader.get_source(fullmodule)
- except (AttributeError, ImportError):
- # If module is not Python source, we cannot do anything.
- return tree
- else:
- if source is None:
- return tree
- fname = spec.loader.get_filename(fullmodule)
- return _create_tree(fullmodule, path, fname, source, tree, inpackage)
- def _create_tree(fullmodule, path, fname, source, tree, inpackage):
- """Return the tree for a particular module.
- fullmodule (full module name), inpackage+module, becomes o.module.
- path is passed to recursive calls of _readmodule.
- fname becomes o.file.
- source is tokenized. Imports cause recursive calls to _readmodule.
- tree is {} or {'__path__': <submodule search locations>}.
- inpackage, None or string, is passed to recursive calls of _readmodule.
- The effect of recursive calls is mutation of global _modules.
- """
- f = io.StringIO(source)
- stack = [] # Initialize stack of (class, indent) pairs.
- g = tokenize.generate_tokens(f.readline)
- try:
- for tokentype, token, start, _end, _line in g:
- if tokentype == DEDENT:
- lineno, thisindent = start
- # Close previous nested classes and defs.
- while stack and stack[-1][1] >= thisindent:
- del stack[-1]
- elif token == 'def':
- lineno, thisindent = start
- # Close previous nested classes and defs.
- while stack and stack[-1][1] >= thisindent:
- del stack[-1]
- tokentype, func_name, start = next(g)[0:3]
- if tokentype != NAME:
- continue # Skip def with syntax error.
- cur_func = None
- if stack:
- cur_obj = stack[-1][0]
- cur_func = _nest_function(cur_obj, func_name, lineno)
- else:
- # It is just a function.
- cur_func = Function(fullmodule, func_name, fname, lineno)
- tree[func_name] = cur_func
- stack.append((cur_func, thisindent))
- elif token == 'class':
- lineno, thisindent = start
- # Close previous nested classes and defs.
- while stack and stack[-1][1] >= thisindent:
- del stack[-1]
- tokentype, class_name, start = next(g)[0:3]
- if tokentype != NAME:
- continue # Skip class with syntax error.
- # Parse what follows the class name.
- tokentype, token, start = next(g)[0:3]
- inherit = None
- if token == '(':
- names = [] # Initialize list of superclasses.
- level = 1
- super = [] # Tokens making up current superclass.
- while True:
- tokentype, token, start = next(g)[0:3]
- if token in (')', ',') and level == 1:
- n = "".join(super)
- if n in tree:
- # We know this super class.
- n = tree[n]
- else:
- c = n.split('.')
- if len(c) > 1:
- # Super class form is module.class:
- # look in module for class.
- m = c[-2]
- c = c[-1]
- if m in _modules:
- d = _modules[m]
- if c in d:
- n = d[c]
- names.append(n)
- super = []
- if token == '(':
- level += 1
- elif token == ')':
- level -= 1
- if level == 0:
- break
- elif token == ',' and level == 1:
- pass
- # Only use NAME and OP (== dot) tokens for type name.
- elif tokentype in (NAME, OP) and level == 1:
- super.append(token)
- # Expressions in the base list are not supported.
- inherit = names
- if stack:
- cur_obj = stack[-1][0]
- cur_class = _nest_class(
- cur_obj, class_name, lineno, inherit)
- else:
- cur_class = Class(fullmodule, class_name, inherit,
- fname, lineno)
- tree[class_name] = cur_class
- stack.append((cur_class, thisindent))
- elif token == 'import' and start[1] == 0:
- modules = _getnamelist(g)
- for mod, _mod2 in modules:
- try:
- # Recursively read the imported module.
- if inpackage is None:
- _readmodule(mod, path)
- else:
- try:
- _readmodule(mod, path, inpackage)
- except ImportError:
- _readmodule(mod, [])
- except:
- # If we can't find or parse the imported module,
- # too bad -- don't die here.
- pass
- elif token == 'from' and start[1] == 0:
- mod, token = _getname(g)
- if not mod or token != "import":
- continue
- names = _getnamelist(g)
- try:
- # Recursively read the imported module.
- d = _readmodule(mod, path, inpackage)
- except:
- # If we can't find or parse the imported module,
- # too bad -- don't die here.
- continue
- # Add any classes that were defined in the imported module
- # to our name space if they were mentioned in the list.
- for n, n2 in names:
- if n in d:
- tree[n2 or n] = d[n]
- elif n == '*':
- # Don't add names that start with _.
- for n in d:
- if n[0] != '_':
- tree[n] = d[n]
- except StopIteration:
- pass
- f.close()
- return tree
- def _getnamelist(g):
- """Return list of (dotted-name, as-name or None) tuples for token source g.
- An as-name is the name that follows 'as' in an as clause.
- """
- names = []
- while True:
- name, token = _getname(g)
- if not name:
- break
- if token == 'as':
- name2, token = _getname(g)
- else:
- name2 = None
- names.append((name, name2))
- while token != "," and "\n" not in token:
- token = next(g)[1]
- if token != ",":
- break
- return names
- def _getname(g):
- "Return (dotted-name or None, next-token) tuple for token source g."
- parts = []
- tokentype, token = next(g)[0:2]
- if tokentype != NAME and token != '*':
- return (None, token)
- parts.append(token)
- while True:
- tokentype, token = next(g)[0:2]
- if token != '.':
- break
- tokentype, token = next(g)[0:2]
- if tokentype != NAME:
- break
- parts.append(token)
- return (".".join(parts), token)
- def _main():
- "Print module output (default this file) for quick visual check."
- import os
- try:
- mod = sys.argv[1]
- except:
- mod = __file__
- if os.path.exists(mod):
- path = [os.path.dirname(mod)]
- mod = os.path.basename(mod)
- if mod.lower().endswith(".py"):
- mod = mod[:-3]
- else:
- path = []
- tree = readmodule_ex(mod, path)
- lineno_key = lambda a: getattr(a, 'lineno', 0)
- objs = sorted(tree.values(), key=lineno_key, reverse=True)
- indent_level = 2
- while objs:
- obj = objs.pop()
- if isinstance(obj, list):
- # Value is a __path__ key.
- continue
- if not hasattr(obj, 'indent'):
- obj.indent = 0
- if isinstance(obj, _Object):
- new_objs = sorted(obj.children.values(),
- key=lineno_key, reverse=True)
- for ob in new_objs:
- ob.indent = obj.indent + indent_level
- objs.extend(new_objs)
- if isinstance(obj, Class):
- print("{}class {} {} {}"
- .format(' ' * obj.indent, obj.name, obj.super, obj.lineno))
- elif isinstance(obj, Function):
- print("{}def {} {}".format(' ' * obj.indent, obj.name, obj.lineno))
- if __name__ == "__main__":
- _main()
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