#!/usr/bin/env python

  """Find Kconfig symbols that are referenced but not defined."""

  # (c) 2014-2015 Valentin Rothberg <Valentin.Rothberg@lip6.fr>

  # (c) 2014 Stefan Hengelein <stefan.hengelein@fau.de>

  #

  # Licensed under the terms of the GNU GPL License version 2

  
  
  import os
  import re

  import sys

  from subprocess import Popen, PIPE, STDOUT

  from optparse import OptionParser

  
  # regex expressions

  OPERATORS = r"&|\(|\)|\||\!"

  FEATURE = r"(?:\w*[A-Z0-9]\w*){2,}"
  DEF = r"^\s*(?:menu){,1}config\s+(" + FEATURE + r")\s*"

  EXPR = r"(?:" + OPERATORS + r"|\s|" + FEATURE + r")+"
  STMT = r"^\s*(?:if|select|depends\s+on)\s+" + EXPR

  SOURCE_FEATURE = r"(?:\W|\b)+[D]{,1}CONFIG_(" + FEATURE + r")"

  # regex objects

  REGEX_FILE_KCONFIG = re.compile(r".*Kconfig[\.\w+\-]*$")
  REGEX_FEATURE = re.compile(r"(" + FEATURE + r")")

  REGEX_SOURCE_FEATURE = re.compile(SOURCE_FEATURE)
  REGEX_KCONFIG_DEF = re.compile(DEF)

  REGEX_KCONFIG_EXPR = re.compile(EXPR)
  REGEX_KCONFIG_STMT = re.compile(STMT)
  REGEX_KCONFIG_HELP = re.compile(r"^\s+(help|---help---)\s*$")
  REGEX_FILTER_FEATURES = re.compile(r"[A-Za-z0-9]$")

  def parse_options():
      """The user interface of this module."""
      usage = "%prog [options]
  
  "                                              \
              "Run this tool to detect Kconfig symbols that are referenced but " \
              "not defined in
  Kconfig.  The output of this tool has the "       \
              "format \'Undefined symbol\\tFile list\'
  
  "                      \
              "If no option is specified, %prog will default to check your
  "    \
              "current tree.  Please note that specifying commits will "         \
              "\'git reset --hard\'
  your current tree!  You may save "          \
              "uncommitted changes to avoid losing data."
  
      parser = OptionParser(usage=usage)
  
      parser.add_option('-c', '--commit', dest='commit', action='store',
                        default="",
                        help="Check if the specified commit (hash) introduces "
                             "undefined Kconfig symbols.")
  
      parser.add_option('-d', '--diff', dest='diff', action='store',
                        default="",
                        help="Diff undefined symbols between two commits.  The "
                             "input format bases on Git log's "
                             "\'commmit1..commit2\'.")
  
      parser.add_option('', '--force', dest='force', action='store_true',
                        default=False,
                        help="Reset current Git tree even when it's dirty.")
  
      (opts, _) = parser.parse_args()
  
      if opts.commit and opts.diff:
          sys.exit("Please specify only one option at once.")
  
      if opts.diff and not re.match(r"^[\w\-\.]+\.\.[\w\-\.]+$", opts.diff):
          sys.exit("Please specify valid input in the following format: "
                   "\'commmit1..commit2\'")
  
      if opts.commit or opts.diff:
          if not opts.force and tree_is_dirty():
              sys.exit("The current Git tree is dirty (see 'git status').  "
                       "Running this script may
  delete important data since it "
                       "calls 'git reset --hard' for some performance
  reasons. "
                       " Please run this script in a clean Git tree or pass "
                       "'--force' if you
  want to ignore this warning and "
                       "continue.")
  
      return opts

  def main():
      """Main function of this module."""

      opts = parse_options()
  
      if opts.commit or opts.diff:
          head = get_head()
  
          # get commit range
          commit_a = None
          commit_b = None
          if opts.commit:
              commit_a = opts.commit + "~"
              commit_b = opts.commit
          elif opts.diff:
              split = opts.diff.split("..")
              commit_a = split[0]
              commit_b = split[1]
              undefined_a = {}
              undefined_b = {}
  
          # get undefined items before the commit
          execute("git reset --hard %s" % commit_a)
          undefined_a = check_symbols()
  
          # get undefined items for the commit
          execute("git reset --hard %s" % commit_b)
          undefined_b = check_symbols()
  
          # report cases that are present for the commit but not before

          for feature in sorted(undefined_b):

              # feature has not been undefined before
              if not feature in undefined_a:

                  files = sorted(undefined_b.get(feature))

                  print "%s\t%s" % (feature, ", ".join(files))
              # check if there are new files that reference the undefined feature
              else:

                  files = sorted(undefined_b.get(feature) -
                                 undefined_a.get(feature))

                  if files:
                      print "%s\t%s" % (feature, ", ".join(files))
  
          # reset to head
          execute("git reset --hard %s" % head)
  
      # default to check the entire tree
      else:
          undefined = check_symbols()

          for feature in sorted(undefined):
              files = sorted(undefined.get(feature))
              print "%s\t%s" % (feature, ", ".join(files))

  
  
  def execute(cmd):
      """Execute %cmd and return stdout.  Exit in case of error."""
      pop = Popen(cmd, stdout=PIPE, stderr=STDOUT, shell=True)
      (stdout, _) = pop.communicate()  # wait until finished
      if pop.returncode != 0:
          sys.exit(stdout)
      return stdout
  
  
  def tree_is_dirty():
      """Return true if the current working tree is dirty (i.e., if any file has
      been added, deleted, modified, renamed or copied but not committed)."""
      stdout = execute("git status --porcelain")
      for line in stdout:
          if re.findall(r"[URMADC]{1}", line[:2]):
              return True
      return False
  
  
  def get_head():
      """Return commit hash of current HEAD."""
      stdout = execute("git rev-parse HEAD")
      return stdout.strip('
  ')
  
  
  def check_symbols():
      """Find undefined Kconfig symbols and return a dict with the symbol as key
      and a list of referencing files as value."""

      source_files = []
      kconfig_files = []
      defined_features = set()

      referenced_features = dict()  # {feature: [files]}

  
      # use 'git ls-files' to get the worklist

      stdout = execute("git ls-files")

      if len(stdout) > 0 and stdout[-1] == "
  ":
          stdout = stdout[:-1]
  
      for gitfile in stdout.rsplit("
  "):

          if ".git" in gitfile or "ChangeLog" in gitfile or      \
                  ".log" in gitfile or os.path.isdir(gitfile) or \
                  gitfile.startswith("tools/"):

              continue
          if REGEX_FILE_KCONFIG.match(gitfile):
              kconfig_files.append(gitfile)
          else:

              # all non-Kconfig files are checked for consistency

              source_files.append(gitfile)
  
      for sfile in source_files:
          parse_source_file(sfile, referenced_features)
  
      for kfile in kconfig_files:
          parse_kconfig_file(kfile, defined_features, referenced_features)

      undefined = {}  # {feature: [files]}

      for feature in sorted(referenced_features):

          # filter some false positives
          if feature == "FOO" or feature == "BAR" or \
                  feature == "FOO_BAR" or feature == "XXX":
              continue

          if feature not in defined_features:
              if feature.endswith("_MODULE"):

                  # avoid false positives for kernel modules

                  if feature[:-len("_MODULE")] in defined_features:
                      continue

              undefined[feature] = referenced_features.get(feature)
      return undefined

  
  
  def parse_source_file(sfile, referenced_features):
      """Parse @sfile for referenced Kconfig features."""
      lines = []
      with open(sfile, "r") as stream:
          lines = stream.readlines()
  
      for line in lines:
          if not "CONFIG_" in line:
              continue
          features = REGEX_SOURCE_FEATURE.findall(line)
          for feature in features:
              if not REGEX_FILTER_FEATURES.search(feature):
                  continue

              sfiles = referenced_features.get(feature, set())
              sfiles.add(sfile)
              referenced_features[feature] = sfiles

  
  
  def get_features_in_line(line):
      """Return mentioned Kconfig features in @line."""
      return REGEX_FEATURE.findall(line)
  
  
  def parse_kconfig_file(kfile, defined_features, referenced_features):
      """Parse @kfile and update feature definitions and references."""
      lines = []
      skip = False
  
      with open(kfile, "r") as stream:
          lines = stream.readlines()
  
      for i in range(len(lines)):
          line = lines[i]
          line = line.strip('
  ')

          line = line.split("#")[0]  # ignore comments

  
          if REGEX_KCONFIG_DEF.match(line):
              feature_def = REGEX_KCONFIG_DEF.findall(line)
              defined_features.add(feature_def[0])
              skip = False
          elif REGEX_KCONFIG_HELP.match(line):
              skip = True
          elif skip:

              # ignore content of help messages

              pass
          elif REGEX_KCONFIG_STMT.match(line):
              features = get_features_in_line(line)

              # multi-line statements

              while line.endswith("\\"):
                  i += 1
                  line = lines[i]
                  line = line.strip('
  ')
                  features.extend(get_features_in_line(line))
              for feature in set(features):
                  paths = referenced_features.get(feature, set())
                  paths.add(kfile)
                  referenced_features[feature] = paths
  
  
  if __name__ == "__main__":
      main()