Introduce Git.pm (v4)
[git/git.git] / perl / Git.pm
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b1edc53d
PB
1=head1 NAME
2
3Git - Perl interface to the Git version control system
4
5=cut
6
7
8package Git;
9
10use strict;
11
12
13BEGIN {
14
15our ($VERSION, @ISA, @EXPORT, @EXPORT_OK);
16
17# Totally unstable API.
18$VERSION = '0.01';
19
20
21=head1 SYNOPSIS
22
23 use Git;
24
25 my $version = Git::command_oneline('version');
26
27 Git::command_noisy('update-server-info');
28
29 my $repo = Git->repository (Directory => '/srv/git/cogito.git');
30
31
32 my @revs = $repo->command('rev-list', '--since=last monday', '--all');
33
34 my $fh = $repo->command_pipe('rev-list', '--since=last monday', '--all');
35 my $lastrev = <$fh>; chomp $lastrev;
36 close $fh; # You may want to test rev-list exit status here
37
38 my $lastrev = $repo->command_oneline('rev-list', '--all');
39
40=cut
41
42
43require Exporter;
44
45@ISA = qw(Exporter);
46
47@EXPORT = qw();
48
49# Methods which can be called as standalone functions as well:
50@EXPORT_OK = qw(command command_oneline command_pipe command_noisy
51 hash_object);
52
53
54=head1 DESCRIPTION
55
56This module provides Perl scripts easy way to interface the Git version control
57system. The modules have an easy and well-tested way to call arbitrary Git
58commands; in the future, the interface will also provide specialized methods
59for doing easily operations which are not totally trivial to do over
60the generic command interface.
61
62While some commands can be executed outside of any context (e.g. 'version'
63or 'init-db'), most operations require a repository context, which in practice
64means getting an instance of the Git object using the repository() constructor.
65(In the future, we will also get a new_repository() constructor.) All commands
66called as methods of the object are then executed in the context of the
67repository.
68
69TODO: In the future, we might also do
70
71 my $subdir = $repo->subdir('Documentation');
72 # Gets called in the subdirectory context:
73 $subdir->command('status');
74
75 my $remoterepo = $repo->remote_repository (Name => 'cogito', Branch => 'master');
76 $remoterepo ||= Git->remote_repository ('http://git.or.cz/cogito.git/');
77 my @refs = $remoterepo->refs();
78
79So far, all functions just die if anything goes wrong. If you don't want that,
80make appropriate provisions to catch the possible deaths. Better error recovery
81mechanisms will be provided in the future.
82
83Currently, the module merely wraps calls to external Git tools. In the future,
84it will provide a much faster way to interact with Git by linking directly
85to libgit. This should be completely opaque to the user, though (performance
86increate nonwithstanding).
87
88=cut
89
90
91use Carp qw(carp croak);
92
93require XSLoader;
94XSLoader::load('Git', $VERSION);
95
96}
97
98
99=head1 CONSTRUCTORS
100
101=over 4
102
103=item repository ( OPTIONS )
104
105=item repository ( DIRECTORY )
106
107=item repository ()
108
109Construct a new repository object.
110C<OPTIONS> are passed in a hash like fashion, using key and value pairs.
111Possible options are:
112
113B<Repository> - Path to the Git repository.
114
115B<WorkingCopy> - Path to the associated working copy; not strictly required
116as many commands will happily crunch on a bare repository.
117
118B<Directory> - Path to the Git working directory in its usual setup. This
119is just for convenient setting of both C<Repository> and C<WorkingCopy>
120at once: If the directory as a C<.git> subdirectory, C<Repository> is pointed
121to the subdirectory and the directory is assumed to be the working copy.
122If the directory does not have the subdirectory, C<WorkingCopy> is left
123undefined and C<Repository> is pointed to the directory itself.
124
125B<GitPath> - Path to the C<git> binary executable. By default the C<$PATH>
126is searched for it.
127
128You should not use both C<Directory> and either of C<Repository> and
129C<WorkingCopy> - the results of that are undefined.
130
131Alternatively, a directory path may be passed as a single scalar argument
132to the constructor; it is equivalent to setting only the C<Directory> option
133field.
134
135Calling the constructor with no options whatsoever is equivalent to
136calling it with C<< Directory => '.' >>.
137
138=cut
139
140sub repository {
141 my $class = shift;
142 my @args = @_;
143 my %opts = ();
144 my $self;
145
146 if (defined $args[0]) {
147 if ($#args % 2 != 1) {
148 # Not a hash.
149 $#args == 0 or croak "bad usage";
150 %opts = (Directory => $args[0]);
151 } else {
152 %opts = @args;
153 }
154
155 if ($opts{Directory}) {
156 -d $opts{Directory} or croak "Directory not found: $!";
157 if (-d $opts{Directory}."/.git") {
158 # TODO: Might make this more clever
159 $opts{WorkingCopy} = $opts{Directory};
160 $opts{Repository} = $opts{Directory}."/.git";
161 } else {
162 $opts{Repository} = $opts{Directory};
163 }
164 delete $opts{Directory};
165 }
166 }
167
168 $self = { opts => \%opts };
169 bless $self, $class;
170}
171
172
173=back
174
175=head1 METHODS
176
177=over 4
178
179=item command ( COMMAND [, ARGUMENTS... ] )
180
181Execute the given Git C<COMMAND> (specify it without the 'git-'
182prefix), optionally with the specified extra C<ARGUMENTS>.
183
184The method can be called without any instance or on a specified Git repository
185(in that case the command will be run in the repository context).
186
187In scalar context, it returns all the command output in a single string
188(verbatim).
189
190In array context, it returns an array containing lines printed to the
191command's stdout (without trailing newlines).
192
193In both cases, the command's stdin and stderr are the same as the caller's.
194
195=cut
196
197sub command {
198 my $fh = command_pipe(@_);
199
200 if (not defined wantarray) {
201 _cmd_close($fh);
202
203 } elsif (not wantarray) {
204 local $/;
205 my $text = <$fh>;
206 _cmd_close($fh);
207 return $text;
208
209 } else {
210 my @lines = <$fh>;
211 _cmd_close($fh);
212 chomp @lines;
213 return @lines;
214 }
215}
216
217
218=item command_oneline ( COMMAND [, ARGUMENTS... ] )
219
220Execute the given C<COMMAND> in the same way as command()
221does but always return a scalar string containing the first line
222of the command's standard output.
223
224=cut
225
226sub command_oneline {
227 my $fh = command_pipe(@_);
228
229 my $line = <$fh>;
230 _cmd_close($fh);
231
232 chomp $line;
233 return $line;
234}
235
236
237=item command_pipe ( COMMAND [, ARGUMENTS... ] )
238
239Execute the given C<COMMAND> in the same way as command()
240does but return a pipe filehandle from which the command output can be
241read.
242
243=cut
244
245sub command_pipe {
246 my ($self, $cmd, @args) = _maybe_self(@_);
247
248 $cmd =~ /^[a-z0-9A-Z_-]+$/ or croak "bad command: $cmd";
249
250 my $pid = open(my $fh, "-|");
251 if (not defined $pid) {
252 croak "open failed: $!";
253 } elsif ($pid == 0) {
254 _cmd_exec($self, $cmd, @args);
255 }
256 return $fh;
257}
258
259
260=item command_noisy ( COMMAND [, ARGUMENTS... ] )
261
262Execute the given C<COMMAND> in the same way as command() does but do not
263capture the command output - the standard output is not redirected and goes
264to the standard output of the caller application.
265
266While the method is called command_noisy(), you might want to as well use
267it for the most silent Git commands which you know will never pollute your
268stdout but you want to avoid the overhead of the pipe setup when calling them.
269
270The function returns only after the command has finished running.
271
272=cut
273
274sub command_noisy {
275 my ($self, $cmd, @args) = _maybe_self(@_);
276
277 $cmd =~ /^[a-z0-9A-Z_-]+$/ or croak "bad command: $cmd";
278
279 my $pid = fork;
280 if (not defined $pid) {
281 croak "fork failed: $!";
282 } elsif ($pid == 0) {
283 _cmd_exec($self, $cmd, @args);
284 }
285 if (waitpid($pid, 0) > 0 and $? != 0) {
286 croak "exit status: $?";
287 }
288}
289
290
291=item hash_object ( FILENAME [, TYPE ] )
292
293=item hash_object ( FILEHANDLE [, TYPE ] )
294
295Compute the SHA1 object id of the given C<FILENAME> (or data waiting in
296C<FILEHANDLE>) considering it is of the C<TYPE> object type (C<blob>
297(default), C<commit>, C<tree>).
298
299In case of C<FILEHANDLE> passed instead of file name, all the data
300available are read and hashed, and the filehandle is automatically
301closed. The file handle should be freshly opened - if you have already
302read anything from the file handle, the results are undefined (since
303this function works directly with the file descriptor and internal
304PerlIO buffering might have messed things up).
305
306The method can be called without any instance or on a specified Git repository,
307it makes zero difference.
308
309The function returns the SHA1 hash.
310
311Implementation of this function is very fast; no external command calls
312are involved.
313
314=cut
315
316# Implemented in Git.xs.
317
318
319=back
320
321=head1 TODO
322
323This is still fairly crude.
324We need some good way to report errors back except just dying.
325
326=head1 COPYRIGHT
327
328Copyright 2006 by Petr Baudis E<lt>pasky@suse.czE<gt>.
329
330This module is free software; it may be used, copied, modified
331and distributed under the terms of the GNU General Public Licence,
332either version 2, or (at your option) any later version.
333
334=cut
335
336
337# Take raw method argument list and return ($obj, @args) in case
338# the method was called upon an instance and (undef, @args) if
339# it was called directly.
340sub _maybe_self {
341 # This breaks inheritance. Oh well.
342 ref $_[0] eq 'Git' ? @_ : (undef, @_);
343}
344
345# When already in the subprocess, set up the appropriate state
346# for the given repository and execute the git command.
347sub _cmd_exec {
348 my ($self, @args) = @_;
349 if ($self) {
350 $self->{opts}->{Repository} and $ENV{'GIT_DIR'} = $self->{opts}->{Repository};
351 $self->{opts}->{WorkingCopy} and chdir($self->{opts}->{WorkingCopy});
352 }
353 my $git = $self->{opts}->{GitPath};
354 $git ||= 'git';
355 exec ($git, @args) or croak "exec failed: $!";
356}
357
358# Close pipe to a subprocess.
359sub _cmd_close {
360 my ($fh) = @_;
361 if (not close $fh) {
362 if ($!) {
363 # It's just close, no point in fatalities
364 carp "error closing pipe: $!";
365 } elsif ($? >> 8) {
366 croak "exit status: ".($? >> 8);
367 }
368 # else we might e.g. closed a live stream; the command
369 # dying of SIGPIPE would drive us here.
370 }
371}
372
373
374# Trickery for .xs routines: In order to avoid having some horrid
375# C code trying to do stuff with undefs and hashes, we gate all
376# xs calls through the following and in case we are being ran upon
377# an instance call a C part of the gate which will set up the
378# environment properly.
379sub _call_gate {
380 my $xsfunc = shift;
381 my ($self, @args) = _maybe_self(@_);
382
383 if (defined $self) {
384 # XXX: We ignore the WorkingCopy! To properly support
385 # that will require heavy changes in libgit.
386
387 # XXX: And we ignore everything else as well. libgit
388 # at least needs to be extended to let us specify
389 # the $GIT_DIR instead of looking it up in environment.
390 #xs_call_gate($self->{opts}->{Repository});
391 }
392
393 &$xsfunc(@args);
394}
395
396sub AUTOLOAD {
397 my $xsname;
398 our $AUTOLOAD;
399 ($xsname = $AUTOLOAD) =~ s/.*:://;
400 croak "&Git::$xsname not defined" if $xsname =~ /^xs_/;
401 $xsname = 'xs_'.$xsname;
402 _call_gate(\&$xsname, @_);
403}
404
405sub DESTROY { }
406
407
4081; # Famous last words