Application: gvSIG desktop

"""Parse a Python file and retrieve classes and methods.

Parse enough of a Python file to recognize class and method

definitions and to find out the superclasses of a class.

The interface consists of a single function:

        readmodule(module, path)

module is the name of a Python module, 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 defined in the module (including classes

that are defined via the from XXX import YYY construct).  The values

are class instances of the class Class defined here.

A class is described by the class Class in this module.  Instances

of this class have the following instance variables:

        name -- the name of the class

        super -- a list of super classes (Class instances)

        methods -- a dictionary of methods

        file -- the file in which the class was defined

        lineno -- the line in the file on which the class statement occurred

The dictionary of methods uses the method names as keys and the line

numbers on which the method was defined as values.

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.

BUGS

- Continuation lines are not dealt with at all.

- While triple-quoted strings won't confuse it, lines that look like

  def, class, import or "from ... import" stmts inside backslash-continued

  single-quoted strings are treated like code.  The expense of stopping

  that isn't worth it.

- Code that doesn't pass tabnanny or python -t will confuse it, unless

  you set the module TABWIDTH vrbl (default 8) to the correct tab width

  for the file.

PACKAGE RELATED BUGS

- If you have a package and a module inside that or another package

  with the same name, module caching doesn't work properly since the

  key is the base name of the module/package.

- The only entry that is returned when you readmodule a package is a

  __path__ whose value is a list which confuses certain class browsers.

- When code does:

  from package import subpackage

  class MyClass(subpackage.SuperClass):

    ...

  It can't locate the parent.  It probably needs to have the same

  hairy logic that the import locator already does.  (This logic

  exists coded in Python in the freeze package.)

"""

import os

import sys

import imp

import re

import string

__all__ = ["readmodule"]

TABWIDTH = 8

_getnext = re.compile(r"""

    (?P<String>

       \""" [^"\\]* (?:

                        (?: \\. | "(?!"") )

                        [^"\\]*

                    )*

       \"""

    |   ''' [^'\\]* (?:

                        (?: \\. | '(?!'') )

                        [^'\\]*

                    )*

        '''

    )

|   (?P<Method>

        ^

        (?P<MethodIndent> [ \t]* )

        def [ \t]+

        (?P<MethodName> [a-zA-Z_] \w* )

        [ \t]* \(

    )

|   (?P<Class>

        ^

        (?P<ClassIndent> [ \t]* )

        class [ \t]+

        (?P<ClassName> [a-zA-Z_] \w* )

        [ \t]*

        (?P<ClassSupers> \( [^)\n]* \) )?

        [ \t]* :

    )

|   (?P<Import>

        ^ import [ \t]+

        (?P<ImportList> [^#;\n]+ )

    )

|   (?P<ImportFrom>

        ^ from [ \t]+

        (?P<ImportFromPath>

            [a-zA-Z_] \w*

            (?:

                [ \t]* \. [ \t]* [a-zA-Z_] \w*

            )*

        )

        [ \t]+

        import [ \t]+

        (?P<ImportFromList> [^#;\n]+ )

    )

""", re.VERBOSE | re.DOTALL | re.MULTILINE).search

_modules = {}                           # cache of modules we've seen

# each Python class is represented by an instance of this class

class Class:

    '''Class to represent a Python class.'''

    def __init__(self, module, name, super, file, lineno):

        self.module = module

        self.name = name

        if super is None:

            super = []

        self.super = super

        self.methods = {}

        self.file = file

        self.lineno = lineno

    def _addmethod(self, name, lineno):

        self.methods[name] = lineno

class Function(Class):

    '''Class to represent a top-level Python function'''

    def __init__(self, module, name, file, lineno):

        Class.__init__(self, module, name, None, file, lineno)

    def _addmethod(self, name, lineno):

        assert 0, "Function._addmethod() shouldn't be called"

def readmodule(module, path=[], inpackage=0):

    '''Backwards compatible interface.

    Like readmodule_ex() but strips Function objects from the

    resulting dictionary.'''

    dict = readmodule_ex(module, path, inpackage)

    res = {}

    for key, value in dict.items():

        if not isinstance(value, Function):

            res[key] = value

    return res

def readmodule_ex(module, path=[], inpackage=0):

    '''Read a module file and return a dictionary of classes.

    Search for MODULE in PATH and sys.path, read and parse the

    module and return a dictionary with one entry for each class

    found in the module.'''

    dict = {}

    i = module.rfind('.')

    if i >= 0:

        # Dotted module name

        package = module[:i].strip()

        submodule = module[i+1:].strip()

        parent = readmodule(package, path, inpackage)

        child = readmodule(submodule, parent['__path__'], 1)

        return child

    if _modules.has_key(module):

        # we've seen this module before...

        return _modules[module]

    if module in sys.builtin_module_names:

        # this is a built-in module

        _modules[module] = dict

        return dict

    # search the path for the module

    f = None

    if inpackage:

        try:

            f, file, (suff, mode, type) = \

                    imp.find_module(module, path)

        except ImportError:

            f = None

    if f is None:

        fullpath = list(path) + sys.path

        f, file, (suff, mode, type) = imp.find_module(module, fullpath)

    if type == imp.PKG_DIRECTORY:

        dict['__path__'] = [file]

        _modules[module] = dict

        path = [file] + path

        f, file, (suff, mode, type) = \

                        imp.find_module('__init__', [file])

    if type != imp.PY_SOURCE:

        # not Python source, can't do anything with this module

        f.close()

        _modules[module] = dict

        return dict

    _modules[module] = dict

    imports = []

    classstack = [] # stack of (class, indent) pairs

    src = f.read()

    f.close()

    # To avoid having to stop the regexp at each newline, instead

    # when we need a line number we simply string.count the number of

    # newlines in the string since the last time we did this; i.e.,

    #    lineno = lineno + \

    #             string.count(src, '\n', last_lineno_pos, here)

    #    last_lineno_pos = here

    countnl = string.count

    lineno, last_lineno_pos = 1, 0

    i = 0

    while 1:

        m = _getnext(src, i)

        if not m:

            break

        start, i = m.span()

        if m.start("Method") >= 0:

            # found a method definition or function

            thisindent = _indent(m.group("MethodIndent"))

            meth_name = m.group("MethodName")

            lineno = lineno + \

                     countnl(src, '\n',

                             last_lineno_pos, start)

            last_lineno_pos = start

            # close all classes indented at least as much

            while classstack and \

                  classstack[-1][1] >= thisindent:

                del classstack[-1]

            if classstack:

                # it's a class method

                cur_class = classstack[-1][0]

                cur_class._addmethod(meth_name, lineno)

            else:

                # it's a function

                f = Function(module, meth_name,

                             file, lineno)

                dict[meth_name] = f

        elif m.start("String") >= 0:

            pass

        elif m.start("Class") >= 0:

            # we found a class definition

            thisindent = _indent(m.group("ClassIndent"))

            # close all classes indented at least as much

            while classstack and \

                  classstack[-1][1] >= thisindent:

                del classstack[-1]

            lineno = lineno + \

                     countnl(src, '\n', last_lineno_pos, start)

            last_lineno_pos = start

            class_name = m.group("ClassName")

            inherit = m.group("ClassSupers")

            if inherit:

                # the class inherits from other classes

                inherit = inherit[1:-1].strip()

                names = []

                for n in inherit.split(','):

                    n = n.strip()

                    if dict.has_key(n):

                        # we know this super class

                        n = dict[n]

                    else:

                        c = n.split('.')

                        if len(c) > 1:

                            # super class

                            # is of the

                            # form module.class:

                            # look in

                            # module for class

                            m = c[-2]

                            c = c[-1]

                            if _modules.has_key(m):

                                d = _modules[m]

                                if d.has_key(c):

                                    n = d[c]

                    names.append(n)

                inherit = names

            # remember this class

            cur_class = Class(module, class_name, inherit,

                              file, lineno)

            dict[class_name] = cur_class

            classstack.append((cur_class, thisindent))

        elif m.start("Import") >= 0:

            # import module

            for n in m.group("ImportList").split(','):

                n = n.strip()

                try:

                    # recursively read the imported module

                    d = readmodule(n, path, inpackage)

                except:

                    ##print 'module', n, 'not found'

                    pass

        elif m.start("ImportFrom") >= 0:

            # from module import stuff

            mod = m.group("ImportFromPath")

            names = m.group("ImportFromList").split(',')

            try:

                # recursively read the imported module

                d = readmodule(mod, path, inpackage)

            except:

                ##print 'module', mod, 'not found'

                continue

            # add any classes that were defined in the

            # imported module to our name space if they

            # were mentioned in the list

            for n in names:

                n = n.strip()

                if d.has_key(n):

                    dict[n] = d[n]

                elif n == '*':

                    # only add a name if not

                    # already there (to mimic what

                    # Python does internally)

                    # also don't add names that

                    # start with _

                    for n in d.keys():

                        if n[0] != '_' and \

                           not dict.has_key(n):

                            dict[n] = d[n]

        else:

            assert 0, "regexp _getnext found something unexpected"

    return dict

def _indent(ws, _expandtabs=string.expandtabs):

    return len(_expandtabs(ws, TABWIDTH))