2 # Documentation is at the __END__
9 my ($running, $ready, $deep, $usrctxt, $evalarg,
10 @stack, @saved, @skippkg, @clients);
17 # Globals - must be defined at startup so that clients can refer to
18 # them right after a C<require DB;>
24 # these are hardcoded in perl source (some are magical)
26 $DB::sub = ''; # name of current subroutine
27 %DB::sub = (); # "filename:fromline-toline" for every known sub
28 $DB::single = 0; # single-step flag (set it to 1 to enable stops in BEGIN/use)
29 $DB::signal = 0; # signal flag (will cause a stop at the next line)
30 $DB::trace = 0; # are we tracing through subroutine calls?
31 @DB::args = (); # arguments of current subroutine or @ARGV array
32 @DB::dbline = (); # list of lines in currently loaded file
33 %DB::dbline = (); # actions in current file (keyed by line number)
34 @DB::ret = (); # return value of last sub executed in list context
35 $DB::ret = ''; # return value of last sub executed in scalar context
37 # other "public" globals
39 $DB::package = ''; # current package space
40 $DB::filename = ''; # current filename
41 $DB::subname = ''; # currently executing sub (fullly qualified name)
42 $DB::lineno = ''; # current line number
44 $DB::VERSION = $DB::VERSION = '1.04';
46 # initialize private globals to avoid warnings
48 $running = 1; # are we running, or are we stopped?
60 # entry point for all subroutine calls
63 push(@stack, $DB::single);
65 $DB::single |= 4 if $#stack == $deep;
66 if ($DB::sub eq 'DESTROY' or substr($DB::sub, -9) eq '::DESTROY' or not defined wantarray) {
68 $DB::single |= pop(@stack);
73 $DB::single |= pop(@stack);
78 $DB::single |= pop(@stack);
84 # this is called by perl for every statement
89 ($DB::package, $DB::filename, $DB::lineno) = caller;
91 return if @skippkg and grep { $_ eq $DB::package } @skippkg;
93 $usrctxt = "package $DB::package;"; # this won't let them modify, alas
94 local(*DB::dbline) = "::_<$DB::filename";
97 if (($stop,$action) = split(/\0/,$DB::dbline{$DB::lineno})) {
102 $stop = 0 unless $stop; # avoid un_init warning
103 $evalarg = "\$DB::signal |= do { $stop; }"; &eval;
104 $DB::dbline{$DB::lineno} =~ s/;9($|\0)/$1/; # clear any temp breakpt
107 if ($DB::single || $DB::trace || $DB::signal) {
108 $DB::subname = ($DB::sub =~ /\'|::/) ? $DB::sub : "${DB::package}::$DB::sub"; #';
109 DB->loadfile($DB::filename, $DB::lineno);
111 $evalarg = $action, &eval if $action;
112 if ($DB::single || $DB::signal) {
113 _outputall($#stack . " levels deep in subroutine calls.\n") if $DB::single & 4;
118 &eval if ($evalarg = DB->prestop);
121 # perform any client-specific prestop actions
122 &eval if ($evalarg = $c->cprestop);
124 # Now sit in an event loop until something sets $running
126 $c->idle; # call client event loop; must not block
127 if ($running == 2) { # client wants something eval-ed
128 &eval if ($evalarg = $c->evalcode);
133 # perform any client-specific poststop actions
134 &eval if ($evalarg = $c->cpoststop);
136 &eval if ($evalarg = DB->poststop);
138 ($@, $!, $,, $/, $\, $^W) = @saved;
143 # this takes its argument via $evalarg to preserve current @_
146 ($@, $!, $,, $/, $\, $^W) = @saved;
147 eval "$usrctxt $evalarg; &DB::save";
148 _outputall($@) if $@;
151 ###############################################################################
152 # no compile-time subroutine call allowed before this point #
153 ###############################################################################
155 use strict; # this can run only after DB() and sub() are defined
158 @saved = ($@, $!, $,, $/, $\, $^W);
159 $, = ""; $/ = "\n"; $\ = ""; $^W = 0;
163 for (@clients) { $_->awaken; }
170 # Client callable (read inheritable) methods defined after this point
176 $s = _clientname($s) if ref($s);
182 $s = _clientname($s) if ref($s);
183 @clients = grep {$_ ne $s} @clients;
185 # $running = 3 unless @clients;
186 exit(0) unless @clients;
191 "$name" =~ /^(.+)=[A-Z]+\(.+\)$/;
210 $s->set_tbreak($i) if $i;
211 for ($i = 0; $i <= $#stack;) {
219 # XXX caller must experimentally determine $i (since it depends
220 # on how many client call frames are between this call and the DB call).
225 my $i = shift; # how many levels to get to DB sub
226 $i = 0 unless defined $i;
227 $stack[$#stack-$i] |= 1;
233 # XXX caller must experimentally determine $start (since it depends
234 # on how many client call frames are between this call and the DB call).
240 my($p,$f,$l,$s,$h,$w,$e,$r,$a, @a, @ret,$i);
241 $start = 1 unless $start;
242 for ($i = $start; ($p,$f,$l,$s,$h,$w,$e,$r) = caller($i); $i++) {
246 s/([^\0]*)/'$1'/ unless /^-?[\d.]+$/;
247 s/([\200-\377])/sprintf("M-%c",ord($1)&0177)/eg;
248 s/([\0-\37\177])/sprintf("^%c",ord($1)^64)/eg;
250 $w = $w ? '@ = ' : '$ = ';
251 $a = $h ? '(' . join(', ', @a) . ')' : '';
252 $e =~ s/\n\s*\;\s*\Z// if $e;
253 $e =~ s/[\\\']/\\$1/g if $e;
256 } elsif (defined $r) {
258 } elsif ($s eq '(eval)') {
261 $f = "file '$f'" unless $f eq '-e';
262 push @ret, "$w&$s$a from $f line $l";
277 $DB::trace = !$DB::trace;
282 # without args: returns all defined subroutine names
283 # with subname args: returns a listref [file, start, end]
291 push @ret, [$DB::sub{$name} =~ /^(.*)\:(\d+)-(\d+)$/]
292 if exists $DB::sub{$name};
296 return keys %DB::sub;
300 # first argument is a filename whose subs will be returned
301 # if a filename is not supplied, all subs in the current
302 # filename are returned.
307 $fname = $DB::filename unless $fname;
308 return grep { $DB::sub{$_} =~ /^$fname/ } keys %DB::sub;
312 # returns a list of all filenames that DB knows about
316 my(@f) = grep(m|^_<|, keys %main::);
317 return map { substr($_,2) } @f;
321 # returns reference to an array holding the lines in currently
330 # loadfile($file, $line)
334 my($file, $line) = @_;
335 if (!defined $main::{'_<' . $file}) {
337 if (($try) = grep(m|^_<.*$file|, keys %main::)) {
338 $file = substr($try,2);
341 if (defined($main::{'_<' . $file})) {
343 # _outputall("Loading file $file..");
344 *DB::dbline = "::_<$file";
345 $DB::filename = $file;
347 # print "2 ", $file, '|', $line, "\n";
348 $c->showfile($file, $line);
360 $fname = $DB::filename unless $fname;
361 local(*DB::dbline) = "::_<$fname";
362 for ($i = 1; $i <= $#DB::dbline; $i++) {
363 $ret{$i} = [$DB::dbline[$i], split(/\0/, $DB::dbline{$i})]
364 if defined $DB::dbline{$i};
375 $i = _find_subline($i) if ($i =~ /\D/);
376 $s->output("Subroutine not found.\n") unless $i;
378 if ($DB::dbline[$i] == 0) {
379 $s->output("Line $i not breakable.\n");
382 $DB::dbline{$i} =~ s/^[^\0]*/$cond/;
390 $i = _find_subline($i) if ($i =~ /\D/);
391 $s->output("Subroutine not found.\n") unless $i;
393 if ($DB::dbline[$i] == 0) {
394 $s->output("Line $i not breakable.\n");
397 $DB::dbline{$i} =~ s/($|\0)/;9$1/; # add one-time-only b.p.
405 $name = "${DB::package}\:\:" . $name if $name !~ /::/;
406 $name = "main" . $name if substr($name,0,2) eq "::";
407 my($fname, $from, $to) = ($DB::sub{$name} =~ /^(.*):(\d+)-(\d+)$/);
409 local *DB::dbline = "::_<$fname";
410 ++$from while $DB::dbline[$from] == 0 && $from < $to;
422 $i = _find_subline($i) if ($i =~ /\D/);
423 $s->output("Subroutine not found.\n") unless $i;
424 if (defined $DB::dbline{$i}) {
425 $DB::dbline{$i} =~ s/^[^\0]+//;
426 if ($DB::dbline{$i} =~ s/^\0?$//) {
427 delete $DB::dbline{$i};
433 for ($i = 1; $i <= $#DB::dbline ; $i++) {
434 if (defined $DB::dbline{$i}) {
435 $DB::dbline{$i} =~ s/^[^\0]+//;
436 if ($DB::dbline{$i} =~ s/^\0?$//) {
437 delete $DB::dbline{$i};
448 $i = _find_subline($i) if ($i =~ /\D/);
449 $s->output("Subroutine not found.\n") unless $i;
451 if ($DB::dbline[$i] == 0) {
452 $s->output("Line $i not actionable.\n");
455 $DB::dbline{$i} =~ s/\0[^\0]*//;
456 $DB::dbline{$i} .= "\0" . $act;
467 $i = _find_subline($i) if ($i =~ /\D/);
468 $s->output("Subroutine not found.\n") unless $i;
469 if ($i && $DB::dbline[$i] != 0) {
470 $DB::dbline{$i} =~ s/\0[^\0]*//;
471 delete $DB::dbline{$i} if $DB::dbline{$i} =~ s/^\0?$//;
476 for ($i = 1; $i <= $#DB::dbline ; $i++) {
477 if (defined $DB::dbline{$i}) {
478 $DB::dbline{$i} =~ s/\0[^\0]*//;
479 delete $DB::dbline{$i} if $DB::dbline{$i} =~ s/^\0?$//;
486 my ($client, $val) = @_;
487 return defined($val) ? $preeval->{$client} = $val : $preeval->{$client};
491 my ($client, $val) = @_;
492 return defined($val) ? $posteval->{$client} = $val : $posteval->{$client};
496 # "pure virtual" methods
499 # client-specific pre/post-stop actions.
503 # client complete startup
508 push @skippkg, @_ if @_;
512 my ($client, $val) = @_;
514 $running = 2; # hand over to DB() to evaluate in its context
515 $ineval->{$client} = $val;
517 return $ineval->{$client};
536 for (@clients) { $_->init }
538 $SIG{'INT'} = \&DB::catch;
540 # disable this if stepping through END blocks is desired
541 # (looks scary and deconstructivist with Swat)
549 DB - programmatic interface to the Perl debugging API
557 # these (inherited) methods can be called by the client
559 CLIENT->register() # register a client package name
560 CLIENT->done() # de-register from the debugging API
561 CLIENT->skippkg('hide::hide') # ask DB not to stop in this package
562 CLIENT->cont([WHERE]) # run some more (until BREAK or another breakpt)
563 CLIENT->step() # single step
564 CLIENT->next() # step over
565 CLIENT->ret() # return from current subroutine
566 CLIENT->backtrace() # return the call stack description
567 CLIENT->ready() # call when client setup is done
568 CLIENT->trace_toggle() # toggle subroutine call trace mode
569 CLIENT->subs([SUBS]) # return subroutine information
570 CLIENT->files() # return list of all files known to DB
571 CLIENT->lines() # return lines in currently loaded file
572 CLIENT->loadfile(FILE,LINE) # load a file and let other clients know
573 CLIENT->lineevents() # return info on lines with actions
574 CLIENT->set_break([WHERE],[COND])
575 CLIENT->set_tbreak([WHERE])
576 CLIENT->clr_breaks([LIST])
577 CLIENT->set_action(WHERE,ACTION)
578 CLIENT->clr_actions([LIST])
579 CLIENT->evalcode(STRING) # eval STRING in executing code's context
580 CLIENT->prestop([STRING]) # execute in code context before stopping
581 CLIENT->poststop([STRING])# execute in code context before resuming
583 # These methods will be called at the appropriate times.
584 # Stub versions provided do nothing.
585 # None of these can block.
587 CLIENT->init() # called when debug API inits itself
588 CLIENT->stop(FILE,LINE) # when execution stops
589 CLIENT->idle() # while stopped (can be a client event loop)
590 CLIENT->cleanup() # just before exit
591 CLIENT->output(LIST) # called to print any output that API must show
595 Perl debug information is frequently required not just by debuggers,
596 but also by modules that need some "special" information to do their
597 job properly, like profilers.
599 This module abstracts and provides all of the hooks into Perl internal
600 debugging functionality, so that various implementations of Perl debuggers
601 (or packages that want to simply get at the "privileged" debugging data)
602 can all benefit from the development of this common code. Currently used
603 by Swat, the perl/Tk GUI debugger.
605 Note that multiple "front-ends" can latch into this debugging API
606 simultaneously. This is intended to facilitate things like
607 debugging with a command line and GUI at the same time, debugging
608 debuggers etc. [Sounds nice, but this needs some serious support -- GSAR]
610 In particular, this API does B<not> provide the following functions:
624 command alias management
628 user interface (tty or graphical)
632 These are intended to be services performed by the clients of this API.
634 This module attempts to be squeaky clean w.r.t C<use strict;> and when
635 warnings are enabled.
638 =head2 Global Variables
640 The following "public" global names can be read by clients of this API.
641 Beware that these should be considered "readonly".
647 Name of current executing subroutine.
651 The keys of this hash are the names of all the known subroutines. Each value
652 is an encoded string that has the sprintf(3) format
653 C<("%s:%d-%d", filename, fromline, toline)>.
657 Single-step flag. Will be true if the API will stop at the next statement.
661 Signal flag. Will be set to a true value if a signal was caught. Clients may
662 check for this flag to abort time-consuming operations.
666 This flag is set to true if the API is tracing through subroutine calls.
670 Contains the arguments of current subroutine, or the C<@ARGV> array if in the
675 List of lines in currently loaded file.
679 Actions in current file (keys are line numbers). The values are strings that
680 have the sprintf(3) format C<("%s\000%s", breakcondition, actioncode)>.
684 Package namespace of currently executing code.
688 Currently loaded filename.
692 Fully qualified name of currently executing subroutine.
696 Line number that will be executed next.
702 The following are methods in the DB base class. A client must
703 access these methods by inheritance (*not* by calling them directly),
704 since the API keeps track of clients through the inheritance
709 =item CLIENT->register()
711 register a client object/package
713 =item CLIENT->evalcode(STRING)
715 eval STRING in executing code context
717 =item CLIENT->skippkg('D::hide')
719 ask DB not to stop in these packages
723 run some more (until a breakpt is reached)
735 de-register from the debugging API
739 =head2 Client Callback Methods
741 The following "virtual" methods can be defined by the client. They will
742 be called by the API at appropriate points. Note that unless specified
743 otherwise, the debug API only defines empty, non-functional default versions
750 Called after debug API inits itself.
752 =item CLIENT->prestop([STRING])
754 Usually inherited from DB package. If no arguments are passed,
755 returns the prestop action string.
759 Called when execution stops (w/ args file, line).
763 Called while stopped (can be a client event loop).
765 =item CLIENT->poststop([STRING])
767 Usually inherited from DB package. If no arguments are passed,
768 returns the poststop action string.
770 =item CLIENT->evalcode(STRING)
772 Usually inherited from DB package. Ask for a STRING to be C<eval>-ed
773 in executing code context.
775 =item CLIENT->cleanup()
777 Called just before exit.
779 =item CLIENT->output(LIST)
781 Called when API must show a message (warnings, errors etc.).
789 The interface defined by this module is missing some of the later additions
790 to perl's debugging functionality. As such, this interface should be considered
791 highly experimental and subject to change.
795 Gurusamy Sarathy gsar@activestate.com
797 This code heavily adapted from an early version of perl5db.pl attributable
798 to Larry Wall and the Perl Porters.