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diff: options handling improvements #371

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Dec 10, 2023
Merged

diff: options handling improvements #371

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108 changes: 54 additions & 54 deletions bin/diff
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Original file line number Diff line number Diff line change
Expand Up @@ -37,9 +37,16 @@ License: perl
use strict;

use File::Basename qw(basename);
use Getopt::Std qw(getopts);

Algorithm::Diff->import('diff');

use constant EX_SUCCESS => 0;
use constant EX_DIFFERENT => 1;
use constant EX_FAILURE => 2;

use vars qw($opt_C $opt_c $opt_e $opt_f $opt_q $opt_U $opt_u);

# GLOBAL VARIABLES ####
# After we've read up to a certain point in each file, the number of items
# we've read from each file will differ by $FLD (could be 0)
Expand All @@ -50,8 +57,9 @@ my $Program = basename($0);
my @Ed_Hunks = ();
########################

my $usage = << "ENDUSAGE";
Usage: $Program [{-c | -C lines -e | -f | -u | -U lines}] oldfile newfile
sub usage {
warn << "ENDUSAGE";
Usage: $Program [-c | -C lines | -e | -f | -q | -u | -U lines] oldfile newfile
-c do a context diff with 3 lines of context
-C do a context diff with 'lines' lines of context (implies -c)
-e create a script for the ed editor to change oldfile to newfile
Expand All @@ -61,59 +69,41 @@ Usage: $Program [{-c | -C lines -e | -f | -u | -U lines}] oldfile newfile
-q report only whether or not the files differ

ENDUSAGE
exit EX_FAILURE;
}

my $Context_Lines = 0; # lines of context to print. 0 for old-style diff
my $Diff_Type = "OLD"; # by default, do standard UNIX diff
my ($opt_c, $opt_u, $opt_e, $opt_f, $opt_q);
while ($ARGV[0] =~ /^-/) {
my $opt = shift;
last if $opt eq '--';
if ($opt =~ /^-C(.*)/) {
$Context_Lines = checklen($1 || shift);
getopts('C:cefqU:u') or usage();
if (defined $opt_C) {
$Context_Lines = checklen($opt_C);
$opt_c = 1;
$Diff_Type = "CONTEXT";
} elsif ($opt =~ /^-c$/) {
set_diff_type('CONTEXT');
} elsif ($opt_c) {
$Context_Lines = 3;
$opt_c = 1;
$Diff_Type = "CONTEXT";
} elsif ($opt =~ /^-e$/) {
$opt_e = 1;
$Diff_Type = "ED";
} elsif ($opt =~ /^-f$/) {
$opt_f = 1;
$Diff_Type = "REVERSE_ED";
} elsif ($opt =~ /^-U(.*)$/) {
$Context_Lines = checklen($1 || shift);
$opt_u = 1;
$Diff_Type = "UNIFIED";
} elsif ($opt =~ /^-u$/) {
$Context_Lines = 3;
$opt_u = 1;
$Diff_Type = "UNIFIED";
} elsif ($opt =~ /^-q$/) {
$Context_Lines = 0;
$opt_q = 1;
$opt_e = 1;
$Diff_Type = "ED";
} elsif ($opt eq '-') {
unshift @ARGV, '-';
last;
} else {
$opt =~ s/^-//;
bag("Illegal option -- $opt\n$usage");
}
set_diff_type('CONTEXT');
}

if ($opt_q and grep($_,($opt_c, $opt_f, $opt_u)) > 1) {
bag("Combining -q with other options is nonsensical");
if ($opt_e || $opt_q) {
set_diff_type('ED');
}

if (grep($_,($opt_c, $opt_e, $opt_f, $opt_u)) > 1) {
bag("Only one of -c, -u, -f, -e are allowed");
if ($opt_f) {
set_diff_type('REVERSE_ED');
}
if (defined $opt_U) {
$Context_Lines = checklen($opt_U);
$opt_u = 1;
set_diff_type('UNIFIED');
} elsif ($opt_u) {
$Context_Lines = 3;
set_diff_type('UNIFIED');
}

if (scalar(@ARGV) != 2) {
bag("Missing argument\n$usage");
if (scalar(@ARGV) < 2) {
warn "$Program: missing argument\n";
usage();
} elsif (scalar(@ARGV) > 2) {
warn "$Program: extra argument: '$ARGV[2]'\n";
usage();
}

######## DO THE DIFF!
Expand All @@ -128,7 +118,7 @@ my ($file1, $file2) = @ARGV;
my ($fh1, $fh2);

if ($file1 eq '-') {
exit 0 if ($file2 eq '-');
exit(EX_SUCCESS) if ($file2 eq '-');
bag("cannot compare '-' to a directory") if (-d $file2);
$fh1 = *STDIN;
} elsif (-d $file1) {
Expand Down Expand Up @@ -158,11 +148,11 @@ close $fh2;

# diff yields lots of pieces, each of which is basically a Block object
my $diffs = diff(\@f1, \@f2);
exit 0 unless @$diffs;
exit(EX_SUCCESS) unless @$diffs;

if ($opt_q and @$diffs) {
if ($opt_q) {
print "Files $file1 and $file2 differ\n";
exit 1;
exit EX_DIFFERENT;
}

if ($Diff_Type =~ /UNIFIED|CONTEXT/) {
Expand Down Expand Up @@ -197,19 +187,29 @@ $oldhunk->output_diff(\@f1, \@f2, $Diff_Type);
# Print hunks backwards if we're doing an ed diff
map {$_->output_ed_diff(\@f1, \@f2, $Diff_Type)} @Ed_Hunks if @Ed_Hunks;

exit 1;
exit EX_DIFFERENT;
# END MAIN PROGRAM

sub bag {
my $msg = shift;
warn "$Program: $msg\n";
exit 2;
exit EX_FAILURE;
}

sub checklen {
my $n = shift;
return int($n) if ($n =~ m/\A[0-9]+\Z/);
bag("Invalid context length '$n'\n$usage");
warn "$Program: invalid context length '$n'\n";
usage();
}

sub set_diff_type {
my $val = shift;
if ($Diff_Type ne 'OLD') {
warn "$Program: incompatible diff type options\n";
usage();
}
$Diff_Type = $val;
}

########
Expand Down Expand Up @@ -757,7 +757,7 @@ diff - compute `intelligent' differences between two files

=head1 SYNOPSIS

diff [{-c | -C lines -e | -f | -u | -U lines}] file1 file2
diff [-c | -C lines | -e | -f | -q | -u | -U lines] file1 file2

=head1 DESCRIPTION

Expand Down