lint

#!/usr/bin/env python
# encoding: utf-8
"""
lint

Validate style guidelines for a given source file.

When run from Xcode, the linter will automatically lint all of the built source files
and headers.

Version 1.0

History:
1.0 - February 27, 2011: Includes a set of simple linters and a delinter for most lints.

Created by Jeff Verkoeyen on 2011-02-27.
Copyright 2009-2011 Facebook

Licensed under the Apache License, Version 2.0 (the "License");
you may not use this file except in compliance with the License.
You may obtain a copy of the License at

   http://www.apache.org/licenses/LICENSE-2.0

Unless required by applicable law or agreed to in writing, software
distributed under the License is distributed on an "AS IS" BASIS,
WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
See the License for the specific language governing permissions and
limitations under the License.
"""

import ConfigParser
import logging
import os
import Paths
import pickle
import re
import string
import sys
from optparse import OptionParser

from Pbxproj import Pbxproj
from Pbxproj import relpath

gcopyrightyears = '2009-2011'
gdivider = '///////////////////////////////////////////////////////////////////////////////////////////////////'

# Program entry. The meat of this script happens in the lint() method below.
def main():
	usage = '''%prog filename

The Three20 Linter.
Verify Three20 style guidelines for source code.'''

	parser = OptionParser(usage = usage)
	parser.add_option("-d", "--delint", dest="delint",
	                  help="Delint the source",
	                  action="store_true")

	(options, args) = parser.parse_args()
	
	if len(args) == 0:
		parser.print_help()

	enabled_for_projects = True
	
	# Allow third-party developers to disable the linter entirely. See config.template for
	# more information in the "lint" section.
	configpath = os.path.join(os.path.dirname(Paths.src_dir), 'config')
	if os.path.exists(configpath):
		config = ConfigParser.ConfigParser()
		config.read(configpath)
		enabled_for_projects = config.getboolean('lint', 'enabled_for_projects')

	# If we're running the linter from Xcode, let's just process the project.
	if 'PROJECT_FILE_PATH' in os.environ:
		if enabled_for_projects:
			lint_project(os.environ['PROJECT_FILE_PATH'], options)
	else:
		for filename in args:
			lint(filename, options)


# This filter makes it possible to set the line number on logging.error calls.
class FilenameFilter(logging.Filter):
	def __init__(self):
		self.lineno = -1

	def filter(self, record):
		record.linenumber = self.lineno
		return True


def lint_project(project_path, options):
	project = Pbxproj.get_pbxproj_by_name(project_path)
	
	tempdir = None
	if os.environ['TEMP_FILES_DIR']:
		tempdir = os.environ['TEMP_FILES_DIR']
	
	# We avoid relinting the same file over and over again by maintaining a mapping of filenames
	# to modified times on disk. We store this information in the project's build directory and
	# load it each time we run the linter for this project.
	# Because we store the mtimes on a per project basis, we shouldn't run into any performance
	# issues with a lint.dat file that's becoming completely massive.
	mtimes = {}
	
	# Read the lint.dat file and unpickle it if we find it.
	if tempdir:
		lintdatpath = os.path.join(os.path.abspath(tempdir), 'lint.dat')
		if os.path.exists(lintdatpath):
			lintdatfile = open(lintdatpath, 'rb')
			mtimes = pickle.load(lintdatfile)

	# The linter script may have changed since we last ran this project, so we might have to
	# force lint every file to update them because there may be new linters.
	
	# Assume that the linter hasn't been run for this project.
	forcelint = True
	
	# Get this script's path
	lintfilename = os.path.realpath(__file__)
	
	# Check the mtime.
	mtime = os.path.getmtime(lintfilename)
	if lintfilename in mtimes:
		if mtime <= mtimes[lintfilename]:
			# The lint script hasn't changed since we last ran this, so we don't have to force
			# lint.
			forcelint = False

	# Store the linter's mtime for future runs.
	mtimes[lintfilename] = mtime

	#
	# Get all of the "built" filenames in this project.
	
	# The "Compile sources" phase files
	filenames = project.get_built_sources()
	
	# The "Copy headers" phase files
	filenames = filenames + project.get_built_headers()
	
	# Iterate through and lint each of the files that have been modified since we last ran
	# the linter, unless we're forcelinting, in which case we lint everything.
	for filename in filenames:
		mtime = os.path.getmtime(filename)
		
		# If the filename isn't in the lint data, we have no idea when it was last modified so
		# we'll run the linter anyway.
		if not forcelint and filename in mtimes:
			# Is it older or unchanged?
			if mtime <= mtimes[filename]:
				# Yeah, let's skip it then.
				continue

		# The beef.
		if lint(filename, options):
			# Only update the last known modification time if there weren't any errors.
			mtimes[filename] = mtime
		else:
			print "If you would like to disable the lint tool, please read the instructions in config.template in the root of the Three20 project"
			if filename in mtimes:
				del mtimes[filename]
	
	# Write out the lint data once we're done with this project. Thanks, pickle!
	if tempdir:
		lintdatfile = open(lintdatpath, 'wb')
		pickle.dump(mtimes, lintdatfile)


# Lint the given filename.
def lint(filename, options):
	logger = logging.getLogger()
	
	f = FilenameFilter()
	logger.addFilter(f)

	# Set up the warning logger format.
	ch = logging.StreamHandler()
	if 'PROJECT_FILE_PATH' in os.environ:
		formatter = logging.Formatter(filename+":%(linenumber)s: warning: "+relpath(os.getcwd(), filename)+":%(linenumber)s: %(message)s")
	else:
		formatter = logging.Formatter(filename+":%(linenumber)s: %(message)s")
	ch.setFormatter(formatter)
	logger.addHandler(ch)

	file = open(filename, 'r')
	filedata = file.read()
	
	did_lint_cleanly = True
	
	# Everything is set up now, let's run through the linters!
	if not lint_basics(filedata, filename, f, options.delint):
		did_lint_cleanly = False

	logger.removeFilter(f)
	logger.removeHandler(ch)
	
	return did_lint_cleanly
	

# Basic lint tests that only look at one line's information.
# If isdelinting is True, this method will try to fix as many lint issues as it can and then
# write the results out to disk.
def lint_basics(filedata, filename, linenofilter, isdelinting = False):
	logger = logging.getLogger()

	lines = string.split(filedata, "\n")
	linenofilter.lineno = 1

	prevline = None
	
	did_lint_cleanly = True
	
	nwarningsfixed = 0
	nwarnings = 0
	if isdelinting:
		newfilelines = []
	
	for line in lines:
		# Check line lengths.
		if len(line) > 100:
			did_lint_cleanly = False
			nwarnings = nwarnings + 1
			
			# This is not something we can fix with the delinter.
			if isdelinting:
				logger.error('I don\'t know how to split this line up.')
			else:
				logger.error('Line length > 100')

		# Check method dividers.
		if not re.search(r'.h$', filename) and re.search(r'^[-+][ ]*\([\w\s*]+\)', line):
			if prevline != gdivider and prevline != ' */':
				did_lint_cleanly = False
				nwarnings = nwarnings + 1
			
				# This is not something we can fix with the delinter.
				if isdelinting:
					if re.match(r'/+', prevline):
						newfilelines.pop()
					newfilelines.append(gdivider)
					nwarningsfixed = nwarningsfixed + 1
				else:
					logger.error('This method is missing a correct divider before it')

		# Properties
		if re.search(r'^@property', line):
			if re.search(r'(NSString|NSArray|NSDictionary|NSSet)[ ]*\*', line) and not re.search(r'copy|readonly', line):
				nwarnings = nwarnings + 1
				if isdelinting:
					line = re.sub(r'\bretain\b', r'copy', line)
					nwarningsfixed = nwarningsfixed + 1
				else:
					did_lint_cleanly = False
					logger.error('Objects that have mutable subclasses, such as NSString, should be copied, not retained')
				
			if re.search(r'^@property\(', line):
				nwarnings = nwarnings + 1
				if isdelinting:
					line = line.rstrip(' \t')
					nwarningsfixed = nwarningsfixed + 1
				else:
					did_lint_cleanly = False
					logger.error('Must be a space after the @property declarator')

		# Trailing whitespace
		if re.search('[ \t]+$', line):
			nwarnings = nwarnings + 1
			if isdelinting:
				line = line.rstrip(' \t')
				nwarningsfixed = nwarningsfixed + 1
			else:
				did_lint_cleanly = False
				logger.error('Trailing whitespace')

		# Spaces after logical constructs
		if re.search('(if|while|for)\(', line, re.IGNORECASE):
			nwarnings = nwarnings + 1
			if isdelinting:
				line = re.sub(r'(if|while|for)\(', r'\1 (', line)
				nwarningsfixed = nwarningsfixed + 1
			else:
				did_lint_cleanly = False
				logger.error('Missing space after logical construct')

		# Boolean checks against non-boolean objects
		# This test is really hard to do without knowing the type of the object.
		#if re.search('[^!]!(?!TTIs|[a-z0-9_.]*\.is|is|_is|has|_has|\[|self\.is|[a-z0-9_]+\.)[a-z0-9_]+', line, re.IGNORECASE):
		#	did_lint_cleanly = False
		#	logger.error('Use if (nil == value) instead of boolean checks for pointers')

		# Else statements must have one empty line before them
		if re.search('}[ ]+else', line, re.IGNORECASE) and prevline != '' and not re.search(r'^[ ]*//', prevline):
			nwarnings = nwarnings + 1
			if isdelinting:
				newfilelines.append('')
				nwarningsfixed = nwarningsfixed + 1
			else:
				did_lint_cleanly = False
				logger.error('There must be one empty line before an else statement')

		# Copyright statement for Facebook
		match = re.match('\/\/ Copyright ([0-9]+-[0-9]+) Facebook', line, re.IGNORECASE)
		if match:
			(copyrightyears, ) = match.groups()
			if copyrightyears != gcopyrightyears:
				nwarnings = nwarnings + 1
				if isdelinting:
					line = re.sub(r'([0-9]+-[0-9]+)', gcopyrightyears, line)
					nwarningsfixed = nwarningsfixed + 1
				else:
					did_lint_cleanly = False
					logger.error('The copyright statement on this file is outdated. Should be 2009-2011')

		if isdelinting:
			newfilelines.append(line)

		prevline = line
		linenofilter.lineno = linenofilter.lineno + 1

	if isdelinting and nwarnings > 0:
		newfiledata = '\n'.join(newfilelines)
		file = open(filename, 'w')
		file.write(newfiledata)

	return did_lint_cleanly

if __name__ == "__main__":
	sys.exit(main())