Add pylint to depot_tools.

third_party/logilab/astng/utils.py

+# copyright 2003-2011 LOGILAB S.A. (Paris, FRANCE), all rights reserved.
+# contact http://www.logilab.fr/ -- mailto:contact@logilab.fr
+# copyright 2003-2010 Sylvain Thenault, all rights reserved.
+# contact mailto:thenault@gmail.com
+#
+# This file is part of logilab-astng.
+#
+# logilab-astng is free software: you can redistribute it and/or modify it
+# under the terms of the GNU Lesser General Public License as published by the
+# Free Software Foundation, either version 2.1 of the License, or (at your
+# option) any later version.
+#
+# logilab-astng is distributed in the hope that it will be useful, but
+# WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+# FITNESS FOR A PARTICULAR PURPOSE.  See the GNU Lesser General Public License
+# for more details.
+#
+# You should have received a copy of the GNU Lesser General Public License along
+# with logilab-astng. If not, see <http://www.gnu.org/licenses/>.
+"""this module contains some utilities to navigate in the tree or to
+extract information from it
+"""
+
+__docformat__ = "restructuredtext en"
+
+from logilab.astng.exceptions import ASTNGBuildingException
+
+
+class ASTWalker:
+    """a walker visiting a tree in preorder, calling on the handler:
+
+    * visit_<class name> on entering a node, where class name is the class of
+    the node in lower case
+
+    * leave_<class name> on leaving a node, where class name is the class of
+    the node in lower case
+    """
+
+    def __init__(self, handler):
+        self.handler = handler
+        self._cache = {}
+
+    def walk(self, node, _done=None):
+        """walk on the tree from <node>, getting callbacks from handler"""
+        if _done is None:
+            _done = set()
+        if node in _done:
+            raise AssertionError((id(node), node, node.parent))
+        _done.add(node)
+        self.visit(node)
+        for child_node in node.get_children():
+            self.handler.set_context(node, child_node)
+            assert child_node is not node
+            self.walk(child_node, _done)
+        self.leave(node)
+        assert node.parent is not node
+
+    def get_callbacks(self, node):
+        """get callbacks from handler for the visited node"""
+        klass = node.__class__
+        methods = self._cache.get(klass)
+        if methods is None:
+            handler = self.handler
+            kid = klass.__name__.lower()
+            e_method = getattr(handler, 'visit_%s' % kid,
+                               getattr(handler, 'visit_default', None))
+            l_method = getattr(handler, 'leave_%s' % kid,
+                               getattr(handler, 'leave_default', None))
+            self._cache[klass] = (e_method, l_method)
+        else:
+            e_method, l_method = methods
+        return e_method, l_method
+
+    def visit(self, node):
+        """walk on the tree from <node>, getting callbacks from handler"""
+        method = self.get_callbacks(node)[0]
+        if method is not None:
+            method(node)
+
+    def leave(self, node):
+        """walk on the tree from <node>, getting callbacks from handler"""
+        method = self.get_callbacks(node)[1]
+        if method is not None:
+            method(node)
+
+
+class LocalsVisitor(ASTWalker):
+    """visit a project by traversing the locals dictionary"""
+    def __init__(self):
+        ASTWalker.__init__(self, self)
+        self._visited = {}
+
+    def visit(self, node):
+        """launch the visit starting from the given node"""
+        if node in self._visited:
+            return
+        self._visited[node] = 1 # FIXME: use set ?
+        methods = self.get_callbacks(node)
+        if methods[0] is not None:
+            methods[0](node)
+        if 'locals' in node.__dict__: # skip Instance and other proxy
+            for name, local_node in node.items():
+                self.visit(local_node)
+        if methods[1] is not None:
+            return methods[1](node)
+
+
+def _check_children(node):
+    """a helper function to check children - parent relations"""
+    for child in node.get_children():
+        ok = False
+        if child is None:
+            print "Hm, child of %s is None" % node
+            continue
+        if not hasattr(child, 'parent'):
+            print " ERROR: %s has child %s %x with no parent" % (node, child, id(child))
+        elif not child.parent:
+            print " ERROR: %s has child %s %x with parent %r" % (node, child, id(child), child.parent)
+        elif child.parent is not node:
+            print " ERROR: %s %x has child %s %x with wrong parent %s" % (node,
+                                      id(node), child, id(child), child.parent)
+        else:
+            ok = True
+        if not ok:
+            print "lines;", node.lineno, child.lineno
+            print "of module", node.root(), node.root().name
+            raise ASTNGBuildingException
+        _check_children(child)
+
+
+from _ast import PyCF_ONLY_AST
+def parse(string):
+    return compile(string, "<string>", 'exec', PyCF_ONLY_AST)
+
+class TreeTester(object):
+    '''A helper class to see _ast tree and compare with astng tree
+
+    indent: string for tree indent representation
+    lineno: bool to tell if we should print the line numbers
+
+    >>> tester = TreeTester('print')
+    >>> print tester.native_tree_repr()
+
+    <Module>
+    .   body = [
+    .   <Print>
+    .   .   nl = True
+    .   ]
+    >>> print tester.astng_tree_repr()
+    Module()
+        body = [
+        Print()
+            dest = 
+            values = [
+            ]
+        ]
+    '''
+
+    indent = '.   '
+    lineno = False
+
+    def __init__(self, sourcecode):
+        self._string = ''
+        self.sourcecode = sourcecode
+        self._ast_node = None
+        self.build_ast()
+
+    def build_ast(self):
+        """build the _ast tree from the source code"""
+        self._ast_node = parse(self.sourcecode)
+
+    def native_tree_repr(self, node=None, indent=''):
+        """get a nice representation of the _ast tree"""
+        self._string = ''
+        if node is None:
+            node = self._ast_node
+        self._native_repr_tree(node, indent)
+        return self._string
+
+
+    def _native_repr_tree(self, node, indent, _done=None):
+        """recursive method for the native tree representation"""
+        from _ast import Load as _Load, Store as _Store, Del as _Del
+        from _ast import AST as Node
+        if _done is None:
+            _done = set()
+        if node in _done:
+            self._string += '\nloop in tree: %r (%s)' % (node,
+                                            getattr(node, 'lineno', None))
+            return
+        _done.add(node)
+        self._string += '\n' + indent +  '<%s>' % node.__class__.__name__
+        indent += self.indent
+        if not hasattr(node, '__dict__'):
+            self._string += '\n' + self.indent + " ** node has no __dict__ " + str(node)
+            return
+        node_dict = node.__dict__
+        if hasattr(node, '_attributes'):
+            for a in node._attributes:
+                attr = node_dict[a]
+                if attr is None:
+                    continue
+                if a in ("lineno", "col_offset") and not self.lineno:
+                    continue
+                self._string +='\n' +  indent + a + " = " + repr(attr)
+        for field in node._fields or ():
+            attr = node_dict[field]
+            if attr is None:
+                continue
+            if isinstance(attr, list):
+                if not attr:
+                    continue
+                self._string += '\n' + indent + field + ' = ['
+                for elt in attr:
+                    self._native_repr_tree(elt, indent, _done)
+                self._string += '\n' + indent + ']'
+                continue
+            if isinstance(attr, (_Load, _Store, _Del)):
+                continue
+            if isinstance(attr, Node):
+                self._string += '\n' + indent + field + " = "
+                self._native_repr_tree(attr, indent, _done)
+            else:
+                self._string += '\n' + indent + field + " = " + repr(attr)
+
+
+    def build_astng_tree(self):
+        """build astng tree from the _ast tree
+        """
+        from logilab.astng.builder import ASTNGBuilder
+        tree = ASTNGBuilder().string_build(self.sourcecode)
+        return tree
+
+    def astng_tree_repr(self, ids=False):
+        """build the astng tree and return a nice tree representation"""
+        mod = self.build_astng_tree()
+        return mod.repr_tree(ids)
+
+
+__all__ = ('LocalsVisitor', 'ASTWalker',)
+