~ubuntu-security/ubuntu-security-tools/trunk

#!/usr/bin/python

# This tool attempts to balance out +/- lines in the same or

# adjacent diff chunks.  When doing parallel builds, output

# frequently gets out of order, needlessly filling the diff

# with harmless changes.  This, in theory, will help to reduce

# that kind of noise when run on the output of

# $UST/build-tools/buildlog-compare

#

# Copyright (C) 2009, Canonical Ltd.

# Author: Kees Cook <kees@ubuntu.com>

import sys

def plus_minus_lines(hunk):

    plus = []

    minus = []

    ready = False

    for line in hunk.splitlines():

        if line.startswith('@@'):

            ready = True

            continue

        if not ready:

            continue

        if line.startswith('-'):

            minus.append(line[1:])

        elif line.startswith('+'):

            plus.append(line[1:])

    return plus, minus

class Hunk(object):

    def __init__(self, text):

        self.lines = text.splitlines()

        self.plus, self.minus = plus_minus_lines(text)

        # collapse against self

        self.collapse(None)

    def has_plus(self, line):

        return (line in self.plus)

    def has_minus(self, line):

        return (line in self.minus)

    def is_empty(self):

        return (len(self.plus) + len(self.minus) == 0)

    def collapse(self, other):

        reduced = False

        #print >>sys.stderr, "Collapsing self to %s" % (other)

        #self.dump("\tself: ")

        #if other:

        #    other.dump("\tother: ")

        lines = []+self.plus

        for line in lines:

            if self.has_minus(line):

                #print >>sys.stderr, "Dropping self '%s'" % (line.replace('\n',''))

                self.drop_line('+'+line)

                self.drop_line('-'+line)

                #self.dump("\t")

                reduced = True

        if other != None:

            lines = []+self.plus

            for line in lines:

                if other.has_minus(line):

                    #print >>sys.stderr, "Dropping other '%s'" % (line.replace('\n',''))

                    self.drop_line('+'+line)

                    other.drop_line('-'+line)

                    #self.dump("\tself: ")

                    #other.dump("\tother: ")

                    reduced = True

            lines = []+self.minus

            for line in lines:

                if other.has_plus(line):

                    #print >>sys.stderr, "Dropping other '%s'" % (line.replace('\n',''))

                    self.drop_line('-'+line)

                    other.drop_line('+'+line)

                    #self.dump("\tself: ")

                    #other.dump("\tother: ")

                    reduced = True

        return reduced

    def drop_line(self, line):

        # Remove from diff lines

        index = self.lines.index(line)

        if index<0:

            return

        self.lines.pop(index)

        # Remove from plus/minus arrays

        if line.startswith('-'):

            index = self.minus.index(line[1:])

            if index>=0:

                self.minus.pop(index)

        elif line.startswith('+'):

            index = self.plus.index(line[1:])

            if index>=0:

                self.plus.pop(index)

    def dump(self, prefix=""):

        ready = False

        for line in self.lines:

            if line.startswith('@@') and self.is_empty():

                break

            print prefix + line

collector = ""

minus = 0

plus = 0

counting = False

hunks = []

for line in sys.stdin:

    if line.startswith('@@'):

        at1, minus, plus, at2 = line.split(' ')

        minus = int(minus.split(',')[1])

        plus = int(plus.split(',')[1])

        collector += line

        counting = True

        continue

    if not counting:

        collector += line

        continue

    else:

        collector += line

        if line.startswith('-'):

            minus = minus - 1

        elif line.startswith('+'):

            plus = plus - 1

        elif line.startswith(' '):

            minus = minus - 1

            plus = plus - 1

        else:

            # Broken patch!

            raise ValueError, "Corrupted patch? '%s'" % (line.replace('\n',''))

        if minus == 0 and plus == 0:

            # HUNK FINISHED

            counting = False

            hunks.append(Hunk(collector))

            collector = ""

            while len(hunks)>1 and hunks[-1].collapse(hunks[-2]):

                # Remove prior hunks if they become empty

                if hunks[-2].is_empty():

                    hunks.pop(-2)

                # Remove empty hunks from the end

                while len(hunks)>0 and hunks[-1].is_empty():

                    hunks.pop()

for i in range(0, len(hunks)):

    hunks[i].dump()