FM / lib2to3

/usr/lib64/python2.7/lib2to3

Name	Size	Mode	Actions
fixes/	-	0755	rm
pgen2/	-	0755	rm
btm_matcher.py	6834	0644	edit dl rm
btm_matcher.pyc	5830	0644	edit dl rm
btm_matcher.pyo	5830	0644	edit dl rm
btm_utils.py	10012	0644	edit dl rm
btm_utils.pyc	7563	0644	edit dl rm
btm_utils.pyo	7563	0644	edit dl rm
fixer_base.py	6780	0644	edit dl rm
fixer_base.pyc	7186	0644	edit dl rm
fixer_base.pyo	7186	0644	edit dl rm
fixer_util.py	14597	0644	edit dl rm
fixer_util.pyc	14683	0644	edit dl rm
fixer_util.pyo	14683	0644	edit dl rm
Grammar.txt	7094	0644	edit dl rm
Grammar2.7.18.final.0.pickle	40486	0644	edit dl rm
main.py	11605	0644	edit dl rm
main.pyc	9831	0644	edit dl rm
main.pyo	9789	0644	edit dl rm
patcomp.py	7065	0644	edit dl rm
patcomp.pyc	6601	0644	edit dl rm
patcomp.pyo	6289	0644	edit dl rm
PatternGrammar.txt	793	0644	edit dl rm
PatternGrammar2.7.18.final.0.pickle	2799	0644	edit dl rm
pygram.py	1158	0644	edit dl rm
pygram.pyc	1441	0644	edit dl rm
pygram.pyo	1441	0644	edit dl rm
pytree.py	29039	0644	edit dl rm
pytree.pyc	30303	0644	edit dl rm
pytree.pyo	29420	0644	edit dl rm
refactor.py	28026	0644	edit dl rm
refactor.pyc	23912	0644	edit dl rm
refactor.pyo	23870	0644	edit dl rm
__init__.py	7	0644	edit dl rm
__init__.pyc	127	0644	edit dl rm
__init__.pyo	127	0644	edit dl rm
__main__.py	67	0644	edit dl rm
__main__.pyc	242	0644	edit dl rm
__main__.pyo	242	0644	edit dl rm

Edit: /usr/lib64/python2.7/lib2to3/btm_matcher.py (6834B)

"""A bottom-up tree matching algorithm implementation meant to speed
up 2to3's matching process. After the tree patterns are reduced to
their rarest linear path, a linear Aho-Corasick automaton is
created. The linear automaton traverses the linear paths from the
leaves to the root of the AST and returns a set of nodes for further
matching. This reduces significantly the number of candidate nodes."""

__author__ = "George Boutsioukis <gboutsioukis@gmail.com>"

import logging
import itertools
from collections import defaultdict

from . import pytree
from .btm_utils import reduce_tree

class BMNode(object):
    """Class for a node of the Aho-Corasick automaton used in matching"""
    count = itertools.count()
    def __init__(self):
        self.transition_table = {}
        self.fixers = []
        self.id = next(BMNode.count)
        self.content = ''

class BottomMatcher(object):
    """The main matcher class. After instantiating the patterns should
    be added using the add_fixer method"""

def __init__(self):
        self.match = set()
        self.root = BMNode()
        self.nodes = [self.root]
        self.fixers = []
        self.logger = logging.getLogger("RefactoringTool")

def add_fixer(self, fixer):
        """Reduces a fixer's pattern tree to a linear path and adds it
        to the matcher(a common Aho-Corasick automaton). The fixer is
        appended on the matching states and called when they are
        reached"""
        self.fixers.append(fixer)
        tree = reduce_tree(fixer.pattern_tree)
        linear = tree.get_linear_subpattern()
        match_nodes = self.add(linear, start=self.root)
        for match_node in match_nodes:
            match_node.fixers.append(fixer)

def add(self, pattern, start):
        "Recursively adds a linear pattern to the AC automaton"
        #print("adding pattern", pattern, "to", start)
        if not pattern:
            #print("empty pattern")
            return [start]
        if isinstance(pattern[0], tuple):
            #alternatives
            #print("alternatives")
            match_nodes = []
            for alternative in pattern[0]:
                #add all alternatives, and add the rest of the pattern
                #to each end node
                end_nodes = self.add(alternative, start=start)
                for end in end_nodes:
                    match_nodes.extend(self.add(pattern[1:], end))
            return match_nodes
        else:
            #single token
            #not last
            if pattern[0] not in start.transition_table:
                #transition did not exist, create new
                next_node = BMNode()
                start.transition_table[pattern[0]] = next_node
            else:
                #transition exists already, follow
                next_node = start.transition_table[pattern[0]]

if pattern[1:]:
                end_nodes = self.add(pattern[1:], start=next_node)
            else:
                end_nodes = [next_node]
            return end_nodes

def run(self, leaves):
        """The main interface with the bottom matcher. The tree is
        traversed from the bottom using the constructed
        automaton. Nodes are only checked once as the tree is
        retraversed. When the automaton fails, we give it one more
        shot(in case the above tree matches as a whole with the
        rejected leaf), then we break for the next leaf. There is the
        special case of multiple arguments(see code comments) where we
        recheck the nodes

Args:
           The leaves of the AST tree to be matched

Returns:
           A dictionary of node matches with fixers as the keys
        """
        current_ac_node = self.root
        results = defaultdict(list)
        for leaf in leaves:
            current_ast_node = leaf
            while current_ast_node:
                current_ast_node.was_checked = True
                for child in current_ast_node.children:
                    # multiple statements, recheck
                    if isinstance(child, pytree.Leaf) and child.value == u";":
                        current_ast_node.was_checked = False
                        break
                if current_ast_node.type == 1:
                    #name
                    node_token = current_ast_node.value
                else:
                    node_token = current_ast_node.type

if node_token in current_ac_node.transition_table:
                    #token matches
                    current_ac_node = current_ac_node.transition_table[node_token]
                    for fixer in current_ac_node.fixers:
                        if not fixer in results:
                            results[fixer] = []
                        results[fixer].append(current_ast_node)

else:
                    #matching failed, reset automaton
                    current_ac_node = self.root
                    if (current_ast_node.parent is not None
                        and current_ast_node.parent.was_checked):
                        #the rest of the tree upwards has been checked, next leaf
                        break

#recheck the rejected node once from the root
                    if node_token in current_ac_node.transition_table:
                        #token matches
                        current_ac_node = current_ac_node.transition_table[node_token]
                        for fixer in current_ac_node.fixers:
                            if not fixer in results.keys():
                                results[fixer] = []
                            results[fixer].append(current_ast_node)

current_ast_node = current_ast_node.parent
        return results

def print_ac(self):
        "Prints a graphviz diagram of the BM automaton(for debugging)"
        print("digraph g{")
        def print_node(node):
            for subnode_key in node.transition_table.keys():
                subnode = node.transition_table[subnode_key]
                print("%d -> %d [label=%s] //%s" %
                      (node.id, subnode.id, type_repr(subnode_key), str(subnode.fixers)))
                if subnode_key == 1:
                    print(subnode.content)
                print_node(subnode)
        print_node(self.root)
        print("}")

# taken from pytree.py for debugging; only used by print_ac
_type_reprs = {}
def type_repr(type_num):
    global _type_reprs
    if not _type_reprs:
        from .pygram import python_symbols
        # printing tokens is possible but not as useful
        # from .pgen2 import token // token.__dict__.items():
        for name, val in python_symbols.__dict__.items():
            if type(val) == int: _type_reprs[val] = name
    return _type_reprs.setdefault(type_num, type_num)

cmd: