+
−#
+
−# verify_target_file.pl
+
−#
+
−# tool to check for make-like dependency
+
−#
+
−# format: verify_target_file.pl temp-file other-dest-file-index other-command other-parameters
+
−#
+
−# the intention of this command is to modify conditionally a file, as would it
+
−# have done by make. since there is no date information, the tool uses the
+
−# content of the file.
+
−#
+
−# the behaviour of this script is somehow specific:
+
−# - it expects that other-dest-file-index decribes which parameter of 
+
−#   other-parameters describes the file to be generated. first parameter is 
+
−#   described with 0 etc. other-command is a perl script and will be invoked 
+
−#   with "do".
+
−# - it invokes other-command, but replaces the first parameter with temp-file
+
−# - it then verifies temp-file against the expected result file (the first
+
−#   parameter). if this file does not exist or is different to temp-file,
+
−#   temp-file is renamed to the first parameter. otherwise (file exists and
+
−#   its content is equal to the content of temp-file), only the temp-file is
+
−#   removed.
+
−# - since the file is already so special, it brings its own comparison tool,
+
−#   that way there is no need to install anything else, that tool compares
+
−#   text files
+
−#
+
−# IMPORTANT:
+
−#   since the used rename does not rename over file system boundaries (at least
+
−#   it is not promised), choose your temp-file accordingly
+
−#
+
−
+
−use strict;
+
−#use warnings;
+
−
+
−my $temp_file = shift;
+
−my $other_dest_file_index = shift;
+
−my $other_command = shift;
+
−my $other_dest_file = $ARGV[$other_dest_file_index];
+
−
+
−# modify command_line
+
−$ARGV[$other_dest_file_index] = $temp_file;
+
−
+
−my $result = do $other_command;
+
−
+
−if ((! defined $result) && ($! || $@))
+
−{
+
−    die "system $other_command failed: $!\n$@";
+
−}
+
−
+
−if (! -e $temp_file)
+
−{
+
−    #something unexpected occured
+
−    die "$temp_file should have been generated";
+
−}
+
−
+
−if (( ! -e $other_dest_file ) ||
+
−    compare_files($other_dest_file, $temp_file) == 0)
+
−{
+
−    unlink $other_dest_file;
+
−    rename $temp_file, $other_dest_file;
+
−}
+
−else
+
−{
+
−    unlink $temp_file;
+
−}
+
−
+
−sub get_contents_of_file
+
−{
+
−    my ($filename) = @_;
+
−
+
−    open(FILE, "<$filename") or die "open failed: $filename";
+
−    my @lines = <FILE>;
+
−    my $text = join '', @lines;
+
−    close FILE;
+
−
+
−    $text
+
−}
+
−
+
−sub compare_files
+
−{
+
−    my ($file1, $file2) = @_;
+
−    
+
−    get_contents_of_file($file1) eq get_contents_of_file($file2)
+
−}
+
−