updatefile.py

#! /usr/bin/env python

# ATTENTION: DO NOT use the tokens used by the file update anywhere within
#            this file. Write < basis-custom > instead, for example.

# ============================================================================
# Copyright (c) 2011-2012 University of Pennsylvania
# Copyright (c) 2013-2014 Andreas Schuh
# All rights reserved.
#
# See COPYING file for license information or visit
# http://opensource.andreasschuh.com/cmake-basis/download.html#license
# ============================================================================

##
# @file  updatefile.py
# @brief Update file from template file while preserving custom sections (deprecated).
#
# This script is used by the BasisUpdate.cmake module. This module is used to
# update files of a project instantiated from a particular revision of the
# BASIS project template during the configure step of CMake. This way,
# projects pull the changes of the compatible template automatically.
# Sections in the original file which are enclosed by the tokens
# \<basis-custom\> and \</basis-custom\> or \<basis-license\> and
# \</basis-license\> (without trailing spaces) are preserved while all other
# content is replaced by the template file. The customized sections are
# inserted into the template in the order they appear in the original file
# and the template file. If more custom sections are present in the original
# file than in the template file, these custom sections are appended at the
# end of the resulting file.
#
# See the documentation of BasisUpdate.cmake for further details.
#
# @ingroup CMakeHelpers

# modules
import os
import sys
import getopt

# constants
customTag  = "basis-custom"
licenseTag = "basis-license"

tokenCustomStart  = "<"  + customTag  + ">"
tokenCustomEnd    = "</" + customTag  + ">"
tokenLicenseStart = "<"  + licenseTag + ">"
tokenLicenseEnd   = "</" + licenseTag + ">"
tokenKeepTemplate = "REMOVE_THIS_STRING_IF_YOU_WANT_TO_KEEP_YOUR_CHANGES"

# ****************************************************************************
def version (progName):
    """Print version information."""
    print progName + "1.0.0"

# ****************************************************************************
def usage (progName):
    print "Usage:"
    print "  " + progName + " [options]"
    print
    print "Required options:"
    print "  [-i --in]       : Filename of original file"
    print "  [-t --template] : Filename of template file"
    print
    print "Options:"
    print "  [-o --out]     Filename of output file. If this option is not given,"
    print "                 changes are not applied and the exit code can be used"
    print "                 to check whether changes would have been applied."
    print "  [-f --force]   Force overwrite of output file. Otherwise ask user."
    print
    print "Return value:"
    print "  0   Merged output differs from input file and output file was"
    print "      written successfully if option -o or --out was given"
    print "  1   Failed to read or write file"
    print "  2   Nothing changed, input file not overwritten"
    print "  3   Merged output differs from input file but user chose not"
    print "      to overwrite input file"
    print "Example:"
    print "  " + progName + " -i CMakeLists.txt -t CMakeLists.txt.template -o CMakeLists.txt"
    print
    print "Contact:"
    print "  SBIA Group <sbia-software at uphs.upenn.edu>"

# ****************************************************************************
def help (progName):
    usage (progName)

# ****************************************************************************
def extractCustomizedSections (input):
    custom = []
    start  = 0
    while True:
        start = input.find (tokenCustomStart, start)
        if start == -1:
            break
        start += len (tokenCustomStart)
        next = input.find (tokenCustomStart, start)
        end  = input.find (tokenCustomEnd,   start)
        if end == -1 or (next != -1 and end > next):
            print "WARNING: Found begin of customized section without end token '" + tokenCustomEnd + "'"
            print "WARNING: Will keep template section instead"
            custom.append (tokenKeepTemplate)
        else:
            custom.append (input [start:end])
        start = next
    return custom

# ****************************************************************************
def replaceCustomizedSections (input, custom):
    start  = 0
    end    = -1
    result = input
    for section in custom:
        if start != -1:
            start = result.find (tokenCustomStart, start)
            end   = -1
        if start != -1:
            start += len (tokenCustomStart)
            end = result.find (tokenCustomEnd, start)
        if start == -1 or end == -1:
            if section != tokenKeepTemplate:
                result = result + '\n'
                result = result + '# ' + tokenCustomStart
                result = result + section
                result = result + tokenCustomEnd
        else:
            if section != tokenKeepTemplate:
                result = result [:start] + section + result [end:]
                end    = start + len (section)
        if end != -1:
            start = end + len (tokenCustomEnd)
    return result

# ****************************************************************************
def extractLicenseSections (input):
    license = []
    start   = 0
    while True:
        start = input.find (tokenLicenseStart, start)
        if start == -1:
            break
        start += len (tokenLicenseStart)
        next = input.find (tokenLicenseStart, start)
        end  = input.find (tokenLicenseEnd,   start)
        if end == -1 or (next != -1 and end > next):
            print "WARNING: Found begin of license section without end token '" + tokenLicenseEnd + "'"
            print "WARNING: Will keep template section instead"
            license.append (tokenKeepTemplate)
        else:
            license.append (input [start:end])
        start = next
    return license

# ****************************************************************************
def replaceLicenseSections (input, license):
    start  = 0
    end    = -1
    result = input
    for section in license:
        if start != -1:
            start = result.find (tokenLicenseStart, start)
        if start != -1:
            start += len (tokenLicenseStart)
            end = result.find (tokenLicenseEnd, start)
        if start != -1 and end != -1:
            if section != tokenKeepTemplate:
                result = result [:start] + section + result [end:]
            start = end + len (tokenLicenseEnd)
    return result


# ****************************************************************************
def run (inputFile, templateFile, outputFile, force):
    # open input and output files
    try:
        fIn = open (inputFile, 'r')
    except IOError:
        sys.stderr.write ("Failed to open file '" + inputFile + "'\n")
        return 1
    try:
        fTem = open (templateFile, 'r')
    except IOError:
        sys.stderr.write ("Failed to open file '" + templateFile + "'\n")
        fIn.close ()
        return 1
    # read files
    input = fIn.read ()
    fIn.close ()
    result = fTem.read ()
    fTem.close ()
    # extract custom sections from input and substitute them in template
    sections = extractCustomizedSections (input)
    result   = replaceCustomizedSections (result, sections)
    # extract license sections from input and substitute them in template
    sections = extractLicenseSections (input)
    result   = replaceLicenseSections (result, sections)
    # check whether input file equals output file
    if inputFile == outputFile:
        # check if content changed
        if result == input:
            return 2
        # query user if file should be overwritten
        if not force:
            try:
                sys.stdout.write ("Template of file '" + inputFile + "' has been modified.\n")
                sys.stdout.write ("Do you want to apply the changes (basis-custom sections remain unchanged)? ")
                sys.stdout.flush ()
                apply = raw_input ()
	        if apply != "y" and apply != "yes":
                    return 3
            except EOFError:
                return 1
    # write result to output file if -o option given
    if outputFile != "":
        try:
            fOut = open (outputFile, 'w')
        except IOError:
            sys.stderr.write ("Failed to open file '" + outputFile + "'\n")
            return 1
        fOut.write (result)
        fOut.close ()
    # done
    if result == input:
        return 2
    return 0

# ****************************************************************************
if __name__ == "__main__":
    progName = os.path.basename (sys.argv [0])
    # options
    verbosity    = 0
    inputFile    = ""
    templateFile = ""
    outputFile   = ""
    force        = False
    # get options
    try:
        opts, files = getopt.gnu_getopt (sys.argv [1:], "uhvVfi:t:o:",
          ["usage","help","version","verbose","force","in=","template=","out="])
    except getopt.GetoptError, err:
        usage (progName)
        print str(err)
        sys.exit(1)
    # parse command line options
    for o, a in opts:
        if o in ["-V", "--verbose"]:
            verbosity += 1
        elif o in ["-h", "--help","-u","--usage"]:
            help (progName)
            sys.exit(0)
        elif o in ["-v", "--version", "--Version"]:
            version (progName)
            sys.exit(0)
        elif o in ["-f", "--force"]:
            force = True
        elif o in ["-i", "--in"]:
            inputFile = os.path.realpath(a)
        elif o in ["-t", "--template"]:
            templateFile = os.path.realpath(a)
        elif o in ["-o", "--out"]:
            outputFile = os.path.realpath(a)
        else:
            assert False, "unhandled option " + o
    # all required inputs specified ?
    if inputFile == "" or templateFile == "":
        usage (progName)
        sys.exit (1)
    # run
    sys.exit (run (inputFile, templateFile, outputFile, force))