File: delta

package info (click to toggle)
delta 2006.08.03-8
  • links: PTS
  • area: main
  • in suites: buster
  • size: 352 kB
  • sloc: perl: 502; makefile: 61; sh: 42; ansic: 11
file content (517 lines) | stat: -rwxr-xr-x 16,771 bytes parent folder | download | duplicates (11)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
#!/usr/bin/perl -w
# delta; see License.txt for copyright and terms of use

use strict;

# ****************
# Implementation of the delta debugging algorithm:
# http://www.st.cs.uni-sb.de/dd/
# Daniel S. Wilkerson dsw@cs.berkeley.edu

# Notes:

# The test script should not depend on the current directory to work.

# Note that 1-minimality does not imply idempotency, so we could
# re-run once it is stuck, perhaps with some randomization.


# Global State ****************

my @chunks = ();                # Once input, is read only.
my @markers = ();               # Delimits a dynamic subsequence of @chunks being considered.
my %test_cache = ();            # Cached test results.

# Mark boundaries that uniquely determine the marked contents.  This
# is used as a shorter key to hash on than the contents themselves.
# Since Perl hashes retain their keys if you don't do this you get a
# horrible memory leak in the test_cache.
my $mark_signature;

# End of the last marker rendered to the tmp file.  Used to figure out
# if the next one abuts it or not.
my $last_mark_stop;
my @current_markers;            # Markers to be rendered to $tmpinput if answer not in cache.

my $tmpinput;                   # Temporary file to render marked subsequence to.
my $last_successful_tmpinput;   # Last one to past the test.

my $tmp_index = 0;              # Cache the last index used to make a tmp file.
my $tmpdir_index = 0;           # Cache the last index used to make a tmp directory.
my $tmpdir;                     # Temporary directory for external programs.
my $logfile = "log";            # File in $tmpdir where log of successful runs is written.
chomp (my $this_dir = `pwd`);   # The current directory.
my $starttime = time;           # The time we started.

my $granularity = "line";       # What is the size of an input chunk?
my $dump_input = 0;             # Dump out the input after reading it in.
my $cp_minimal;                 # Copy the minimal successful test to the current dir.
my $verbose = 0;                # Be more verbose.
my $quiet = 0;                  # Prints go to /dev/null.
my $suffix = ".c";              # For now, our input files are .c files.
my $test;                       # The script to run as the test.

# when true, all operations on input file are in-place:
#   - don't make a new directory
#   - overwrite the original input file with our constructed inputs
my $in_place = 0;
my $start_file;                 # name of input/output file for in_place

my $help_message = <<"END"

    Delta version 2003.7.14
    delta implements the delta-debugging algorithm:
      http://www.st.cs.uni-sb.de/dd/
    Implemented by Daniel Wilkerson.

    usage: $0 [options] start-file

    -test=<testscript>       Specify the test script.
    -suffix=<suffix>         Candidate filename suffix [$suffix]
    -dump_input              Dump input after reading
    -cp_minimal=<filename>   Copy the minimal successful test to the
                             current directory
    -granularity=line        Use lines as the granularity (default)
    -granularity=top_form    Use C top-level forms as the granularity
                             (currently only works with CIL output)
    -log=<file>              Log file for main events
    -quiet                   Say nothing
    -verbose                 Get more verbose output
    -in_place                Overwrite start-file with inputs

    -help                    Get help

    The test program accepts a single argument, the name of the candidate
    file to test.  It is run within a directory containing only that file,
    and it can make temporary files/directories in that directory.  It
    should return zero for a candidate that exhibits the desired property,
    and nonzero for one that does not.

    Example test program (delta will retain a line containing "foo"):
      #!/bin/sh
      grep 'foo' <"\$1" >/dev/null

END
;

# Functions ****************

sub output(@) {
    print @_ unless $quiet;
}

# Return true if the current_markers pass the interesting test.
sub test {
    if (-f "DELTA-STOP") {
        output "Stopping because DELTA-STOP file exists\n";
        exit 1;
    }

    my $cached_result = $test_cache{$mark_signature};
    if (defined $cached_result) {
        output "\tcached\n";
        return $cached_result;
    }

    render_tmpinput();

    my $ret;
    my $input;
    if (!$in_place) {
      output " $tmpinput";
      my $arena = "$tmpdir/arena";
      die if system "rm -rf $arena/*";    # sm: added -r so I can make directories in the arena
      $input = "$tmpdir/$tmpinput";
      my $arena_input = "input$suffix";
      link $input, "$arena/$arena_input";
      # $test gets fully qualified in parse_command_line()
      $ret = system "cd $arena; $test $arena_input";
    }
    else {
      # for in_place, the test program is free to ignore the argument
      # (since it will be known ahead of time) but I'll pass it anyway
      $ret = system "$test $start_file";
      $input = $start_file;
    }

    # from perldoc -f system
    my $signal = $ret & 127;
    my $exitValue = $ret >> 8;

    if ($signal) {
        die "$0 exiting due to signal $signal\n";
    }
    my $result = ! $exitValue;

    # Keep around info only for successful runs.
    if ($result) {
        my $size = (split " ", `wc -l $input`)[0];
        output "\tSUCCESS, lines: $size ****************\n";
        log_msg_time("$tmpinput, lines: $size");
        if (!$in_place) {
          $last_successful_tmpinput = $tmpinput;
        }
        else {
          # make a single copy of the latest successful file
          $last_successful_tmpinput = "${start_file}.ok";
          die "cp failed" if system("cp ${start_file} $last_successful_tmpinput");
        }
    } else {
        output "\n";
        unlink $input unless $in_place;
    }
    return $test_cache{$mark_signature} = $result;
}

# given @current_markers, create a new file by writing the proper
# subset of @chunks to a file; yield its name in $tmpinput
sub render_tmpinput {
    if ($in_place) {
      # I can't just say $tmpinput = $start_file and be done with it,
      # because in many places $tmpdir/ is prefixed (and I don't want
      # to say $tmpdir="." because I want $start_file to possibly be
      # an absolute path.
      open TMPINPUT, ">$start_file" or die $!;
      $tmpinput = $start_file;
    }
    else {
      $tmpinput = unused_tempfile();
      open TMPINPUT, ">${tmpdir}/$tmpinput" or die $!;
    }
    foreach my $marker (@current_markers) {
        for (my $i=$marker->{start}; $i<$marker->{stop}; ++$i) {
            print TMPINPUT $chunks[$i];
        }
    }
    close TMPINPUT or die $!;   # NOTE: Leave $tmpinput defined.
}

sub start_marking {
    @current_markers = ();
    $mark_signature = "";
    undef $last_mark_stop;
}

sub mark {
    my ($marker) = @_;
    push @current_markers, $marker;
    if (defined $last_mark_stop) {
        if ($last_mark_stop < $marker->{start}) {
            $mark_signature .= $last_mark_stop . "]";
            $mark_signature .= "[" . $marker->{start} . ",";
        } elsif ($last_mark_stop == $marker->{start}) {
            # This marker abuts the previous one.
        } else {die}
    } else {
        $mark_signature .= "[" . $marker->{start} . ",";
    }
    $last_mark_stop = $marker->{stop};
}

sub stop_marking {
    $mark_signature .= $last_mark_stop . "]" if defined $last_mark_stop;
    output $mark_signature;
}

sub unused_tempfile {
    die unless defined $tmpdir;
    my $filename;
    do {
        $filename = sprintf("%03d", $tmp_index) . $suffix;
        $tmp_index++;
    } while -e "${tmpdir}/$filename";
    return $filename;
}

sub unused_tempdir {
  my $dirname;
  for (; $dirname = "tmp${tmpdir_index}", -e $dirname; ++$tmpdir_index) {}
  return $dirname;
}

sub select_tmpdir {
    $tmpdir = unused_tempdir() unless defined $tmpdir;
    die if -e $tmpdir;
    mkdir $tmpdir, 0777 or die $!;
    mkdir "${tmpdir}/arena", 0777 or die $!;
}

sub parse_command_line {
    my $str;
    my @non_flags = ();
    while(defined ($str = shift @ARGV)) {
        if ($str=~/^-([^=]+)(=(.+))?/) {
            my ($flag, $argument) = ($1, $3);
            if ($flag eq "help") {
                output $help_message;
                exit 0;
            } elsif ($flag eq "dump_input") {
                $dump_input++;
            } elsif ($flag eq "verbose") {
                $verbose++;
            } elsif ($flag eq "quiet") {
                $quiet++;
            } elsif ($flag eq "granularity") {
                if ($argument eq "line" || $argument eq "top_form") {
                    $granularity = $argument;
                }
            } elsif ($flag eq "cp_minimal") {
                $cp_minimal = $argument;
            } elsif ($flag eq "test") {
                $test = $argument;
            } elsif ($flag eq "suffix") {
                $suffix = $argument;
            } elsif ($flag eq "log") {
                $logfile = $argument;
            } elsif ($flag eq "in_place") {
                $in_place = 1;
            } else {die "Illegal flag: $flag \n"}
        } else {push @non_flags, $str;}
    }
    # Cleaning up.
    die "You specified both verbose and quiet." if $verbose && $quiet;
    push @ARGV, @non_flags;

    # fully qualify $test if it's not already
    die "You must specify a test script.\n" unless defined $test;
    if ($test !~ m"^/") {
      $test = "$this_dir/$test";
    }

    # sm: I like a usage string when I give no arguments but it doesn't
    # make sense to read interactively (stdin is a tty)
    if ((@ARGV == 0) && (-t STDIN)) {
      output $help_message;
      exit(0);
    }

    if ($in_place) {
      if (@ARGV != 1) {
        die "Must give exactly one explicit input file for -in_place."
      }
      $start_file = $ARGV[0];
    }
}

sub render_settings {
    my $out = "delta settings:\n";
    if (!$in_place) {
        $out .= "\ttemporary directory: $tmpdir\n";
    }
    $out .= "\tgranularity: $granularity\n";
    my $input_str;
    if (scalar @ARGV > 0) {
        $input_str = join " ", @ARGV;
    } else {
        $input_str = "<stdin>";
    }
    $out .= "\tinput: $input_str\n";
    return $out;
}

sub read_input_chunks {
    if ($granularity eq "line") {
        while (<>) {push @chunks, $_;} # Read one line at a time.
    } elsif ($granularity eq "top_form") {
        # Read chunks of C top-level forms.  I assume that any line
        # starting with '//# ' followed by a line that does not start
        # with a whitespace is a good boundary for a top-level form.
        # I'm sure you could do this in one line with the proper
        # setting to the regex that is the line seperator.
        my $chunk = "";
        my $a = <>;
        while (<>) {
            if ($a=~m|^//\# | and $_=~m|^\S|) {
                push @chunks, $chunk;
                $chunk = $a;
            } else {
                $chunk .= $a;
            }
            $a = $_;
        }
        $chunk .= $a;
        push @chunks, $chunk;
    } else {die "Illegal granularity setting: $granularity\n"}
}

sub dump_input {
  output "Dumping input ****************\n";
  if ($granularity eq "line") {
      foreach my $chunk (@chunks) {output $chunk;}
  } elsif ($granularity eq "top_form") {
      foreach my $chunk (@chunks) {output "\t-----\n", $chunk}
  } else {die "Illegal granularity setting: $granularity\n"}
  output "****************\n";
}

sub check_initial_input {
    die "The input must consist of at least one chunk." unless @chunks;
    start_marking();
    mark($markers[0]);
    stop_marking();
    die "\n\t**************** FAIL: The initial input does not pass the test.\n\n"
        unless test();
}

sub dump_markers {
  my $i = 0;
  foreach my $marker (@markers) {
    output "\t$i [", $marker->{start}, ", ", $marker->{stop}, "]\n";
    ++$i;
  }
}

sub increase_granularity {
  output "\nIncrease granularity\n";
  output "Before ";
  dump_markers();
  my @newmarkers = ();
  my $split_one = 0;
  foreach my $marker (@markers) {
    my $half = int (($marker->{start} + $marker->{stop}) / 2);
    if ($half == $marker->{start} or $half == $marker->{stop}) {
      push @newmarkers, $marker;
    } else {
      ++$split_one;
      push @newmarkers, {start=>$marker->{start}, stop=>$half};
      push @newmarkers, {start=>$half, stop=>$marker->{stop}};
    }
  }
  @markers = @newmarkers;
  output "After ";
  dump_markers();
  output "\n";
  return $split_one;
}

sub dhms_from_seconds {
    my ($total_seconds) = @_;
    my $sec = $total_seconds % 60;

    my $total_minutes = ($total_seconds - $sec) / 60;
    die unless $total_minutes == (int $total_minutes);
    my $min = $total_minutes % 60;

    my $total_hours = ($total_minutes - $min) / 60;
    die unless $total_hours == (int $total_hours);
    my $hours = $total_hours % 24;

    my $days = ($total_hours - $hours) / 24;
    die unless $days == (int $days);

    return ($days, $hours, $min, $sec);
}

sub timestamp {
    my $now = time;             # Get a timestamp in seconds.
    my $elapsed = $now - $starttime; # Make relative to start time.
    my ($d,$h,$m,$s) = dhms_from_seconds($elapsed); # Convert to more familiar format.
    my $elapsed_dhms = sprintf("%02d:%02d:%02d", $h, $m, $s); # Format.
    if ($d > 0) {
        my $day_str = "$d day";
        $day_str .= "s" if $d > 1;
        $day_str .= ", ";
        $elapsed_dhms = $day_str . $elapsed_dhms;
    }
    my $timestr = scalar localtime($now); # Format as abolute.
    return sprintf("%d sec/%s\t%s", $elapsed, $elapsed_dhms, $timestr);
}

sub log_msg {
    my ($message) = @_;
    open LOG, ">>${logfile}" or die $!;
    print LOG $message, "\n";
    close LOG or die $!;
}

sub log_msg_time {
    my ($message) = @_;
    log_msg(sprintf("%-39s %s", $message, timestamp()));
}

sub done {
    output "Could not increase granularity; we are done.\n";
    output "A log of successful runs is in ${logfile}\n";
    if (defined $cp_minimal) {
        output "Copying minimal run to $cp_minimal\n";
        die "cp failed" if system "cp ${tmpdir}/${last_successful_tmpinput} $cp_minimal";
    }
    if ($in_place) {
        die "cp failed" if system("cp $last_successful_tmpinput $start_file");
    }
    log_msg_time("delta done");
    exit 0;
}

# Main ****************

parse_command_line();
select_tmpdir() unless $in_place;
if (!$in_place) {
  $logfile = "${tmpdir}/$logfile" if $logfile!~m|^/|; # Make absolute.
}
my $settings = render_settings();
log_msg($settings);
if ($verbose) {
    output "\nDelta debugging algorithm, implemented by Daniel S. Wilkerson.\n";
    output $settings, "\n";
}
log_msg_time("delta start");

read_input_chunks();
dump_input() if $dump_input;
$markers[0] = {start=>0, stop=>(scalar @chunks)}; # Initialize one marker.
check_initial_input();          # This is a vital step!  Don't omit it!

big_loop: {

    # NOTE: this paragraph is part of the strict delta algorithm, but
    # it is not actually necessary, so by default I implement
    # something that is a little different from the published
    # algorithm.  Un-comment this paragraph to have the algorithm
    # strictly as published.

    # Test the single markers.
#      foreach my $test_marker (@markers) {
#          start_marking();
#          mark($test_marker);
#          stop_marking();
#          if (test()) {
#              @markers = ($test_marker); # Get rid of all markers but this one.
#              if (increase_granularity()) {redo big_loop;}
#              else {done()}
#          }
#      }

    # Test the complements to single markers.
  complement_loop: {
        my %excluded = ();
        # Try them in reverse.  In both the above "positive" loop and
        # this "negative" loop, the things you are throwing away start
        # at the end of the data, thus the two strategies are
        # consistent.
        foreach my $excluded_marker (reverse @markers) {
            start_marking();
            foreach my $marker (@markers) {
                next if $marker eq $excluded_marker;
                next if $excluded{$marker};
                mark($marker);
            }
            stop_marking();
            if (test()) {
                die "Can't happen" if $excluded{$excluded_marker};
                $excluded{$excluded_marker}++;
            }
        }
        # If any were excluded, record this fact into @markers.
        my @excluded_keys = keys %excluded;
        if (@excluded_keys) {
            @markers = grep {!$excluded{$_}} @markers;
            redo complement_loop; # Retry at the same granularity.
        }
    }

    # None of them worked, increase the granularity.
    if (increase_granularity()) {redo big_loop;}
    else {done()}
}