diff options
Diffstat (limited to 'perl/Git.pm')
| -rw-r--r-- | perl/Git.pm | 844 |
1 files changed, 844 insertions, 0 deletions
diff --git a/perl/Git.pm b/perl/Git.pm new file mode 100644 index 0000000..f2c156c --- /dev/null +++ b/perl/Git.pm @@ -0,0 +1,844 @@ +=head1 NAME + +Git - Perl interface to the Git version control system + +=cut + + +package Git; + +use strict; + + +BEGIN { + +our ($VERSION, @ISA, @EXPORT, @EXPORT_OK); + +# Totally unstable API. +$VERSION = '0.01'; + + +=head1 SYNOPSIS + + use Git; + + my $version = Git::command_oneline('version'); + + git_cmd_try { Git::command_noisy('update-server-info') } + '%s failed w/ code %d'; + + my $repo = Git->repository (Directory => '/srv/git/cogito.git'); + + + my @revs = $repo->command('rev-list', '--since=last monday', '--all'); + + my ($fh, $c) = $repo->command_output_pipe('rev-list', '--since=last monday', '--all'); + my $lastrev = <$fh>; chomp $lastrev; + $repo->command_close_pipe($fh, $c); + + my $lastrev = $repo->command_oneline( [ 'rev-list', '--all' ], + STDERR => 0 ); + +=cut + + +require Exporter; + +@ISA = qw(Exporter); + +@EXPORT = qw(git_cmd_try); + +# Methods which can be called as standalone functions as well: +@EXPORT_OK = qw(command command_oneline command_noisy + command_output_pipe command_input_pipe command_close_pipe + version exec_path hash_object git_cmd_try); + + +=head1 DESCRIPTION + +This module provides Perl scripts easy way to interface the Git version control +system. The modules have an easy and well-tested way to call arbitrary Git +commands; in the future, the interface will also provide specialized methods +for doing easily operations which are not totally trivial to do over +the generic command interface. + +While some commands can be executed outside of any context (e.g. 'version' +or 'init'), most operations require a repository context, which in practice +means getting an instance of the Git object using the repository() constructor. +(In the future, we will also get a new_repository() constructor.) All commands +called as methods of the object are then executed in the context of the +repository. + +Part of the "repository state" is also information about path to the attached +working copy (unless you work with a bare repository). You can also navigate +inside of the working copy using the C<wc_chdir()> method. (Note that +the repository object is self-contained and will not change working directory +of your process.) + +TODO: In the future, we might also do + + my $remoterepo = $repo->remote_repository (Name => 'cogito', Branch => 'master'); + $remoterepo ||= Git->remote_repository ('http://git.or.cz/cogito.git/'); + my @refs = $remoterepo->refs(); + +Currently, the module merely wraps calls to external Git tools. In the future, +it will provide a much faster way to interact with Git by linking directly +to libgit. This should be completely opaque to the user, though (performance +increate nonwithstanding). + +=cut + + +use Carp qw(carp croak); # but croak is bad - throw instead +use Error qw(:try); +use Cwd qw(abs_path); + +} + + +=head1 CONSTRUCTORS + +=over 4 + +=item repository ( OPTIONS ) + +=item repository ( DIRECTORY ) + +=item repository () + +Construct a new repository object. +C<OPTIONS> are passed in a hash like fashion, using key and value pairs. +Possible options are: + +B<Repository> - Path to the Git repository. + +B<WorkingCopy> - Path to the associated working copy; not strictly required +as many commands will happily crunch on a bare repository. + +B<WorkingSubdir> - Subdirectory in the working copy to work inside. +Just left undefined if you do not want to limit the scope of operations. + +B<Directory> - Path to the Git working directory in its usual setup. +The C<.git> directory is searched in the directory and all the parent +directories; if found, C<WorkingCopy> is set to the directory containing +it and C<Repository> to the C<.git> directory itself. If no C<.git> +directory was found, the C<Directory> is assumed to be a bare repository, +C<Repository> is set to point at it and C<WorkingCopy> is left undefined. +If the C<$GIT_DIR> environment variable is set, things behave as expected +as well. + +You should not use both C<Directory> and either of C<Repository> and +C<WorkingCopy> - the results of that are undefined. + +Alternatively, a directory path may be passed as a single scalar argument +to the constructor; it is equivalent to setting only the C<Directory> option +field. + +Calling the constructor with no options whatsoever is equivalent to +calling it with C<< Directory => '.' >>. In general, if you are building +a standard porcelain command, simply doing C<< Git->repository() >> should +do the right thing and setup the object to reflect exactly where the user +is right now. + +=cut + +sub repository { + my $class = shift; + my @args = @_; + my %opts = (); + my $self; + + if (defined $args[0]) { + if ($#args % 2 != 1) { + # Not a hash. + $#args == 0 or throw Error::Simple("bad usage"); + %opts = ( Directory => $args[0] ); + } else { + %opts = @args; + } + } + + if (not defined $opts{Repository} and not defined $opts{WorkingCopy}) { + $opts{Directory} ||= '.'; + } + + if ($opts{Directory}) { + -d $opts{Directory} or throw Error::Simple("Directory not found: $!"); + + my $search = Git->repository(WorkingCopy => $opts{Directory}); + my $dir; + try { + $dir = $search->command_oneline(['rev-parse', '--git-dir'], + STDERR => 0); + } catch Git::Error::Command with { + $dir = undef; + }; + + if ($dir) { + $dir =~ m#^/# or $dir = $opts{Directory} . '/' . $dir; + $opts{Repository} = $dir; + + # If --git-dir went ok, this shouldn't die either. + my $prefix = $search->command_oneline('rev-parse', '--show-prefix'); + $dir = abs_path($opts{Directory}) . '/'; + if ($prefix) { + if (substr($dir, -length($prefix)) ne $prefix) { + throw Error::Simple("rev-parse confused me - $dir does not have trailing $prefix"); + } + substr($dir, -length($prefix)) = ''; + } + $opts{WorkingCopy} = $dir; + $opts{WorkingSubdir} = $prefix; + + } else { + # A bare repository? Let's see... + $dir = $opts{Directory}; + + unless (-d "$dir/refs" and -d "$dir/objects" and -e "$dir/HEAD") { + # Mimick git-rev-parse --git-dir error message: + throw Error::Simple('fatal: Not a git repository'); + } + my $search = Git->repository(Repository => $dir); + try { + $search->command('symbolic-ref', 'HEAD'); + } catch Git::Error::Command with { + # Mimick git-rev-parse --git-dir error message: + throw Error::Simple('fatal: Not a git repository'); + } + + $opts{Repository} = abs_path($dir); + } + + delete $opts{Directory}; + } + + $self = { opts => \%opts }; + bless $self, $class; +} + + +=back + +=head1 METHODS + +=over 4 + +=item command ( COMMAND [, ARGUMENTS... ] ) + +=item command ( [ COMMAND, ARGUMENTS... ], { Opt => Val ... } ) + +Execute the given Git C<COMMAND> (specify it without the 'git-' +prefix), optionally with the specified extra C<ARGUMENTS>. + +The second more elaborate form can be used if you want to further adjust +the command execution. Currently, only one option is supported: + +B<STDERR> - How to deal with the command's error output. By default (C<undef>) +it is delivered to the caller's C<STDERR>. A false value (0 or '') will cause +it to be thrown away. If you want to process it, you can get it in a filehandle +you specify, but you must be extremely careful; if the error output is not +very short and you want to read it in the same process as where you called +C<command()>, you are set up for a nice deadlock! + +The method can be called without any instance or on a specified Git repository +(in that case the command will be run in the repository context). + +In scalar context, it returns all the command output in a single string +(verbatim). + +In array context, it returns an array containing lines printed to the +command's stdout (without trailing newlines). + +In both cases, the command's stdin and stderr are the same as the caller's. + +=cut + +sub command { + my ($fh, $ctx) = command_output_pipe(@_); + + if (not defined wantarray) { + # Nothing to pepper the possible exception with. + _cmd_close($fh, $ctx); + + } elsif (not wantarray) { + local $/; + my $text = <$fh>; + try { + _cmd_close($fh, $ctx); + } catch Git::Error::Command with { + # Pepper with the output: + my $E = shift; + $E->{'-outputref'} = \$text; + throw $E; + }; + return $text; + + } else { + my @lines = <$fh>; + defined and chomp for @lines; + try { + _cmd_close($fh, $ctx); + } catch Git::Error::Command with { + my $E = shift; + $E->{'-outputref'} = \@lines; + throw $E; + }; + return @lines; + } +} + + +=item command_oneline ( COMMAND [, ARGUMENTS... ] ) + +=item command_oneline ( [ COMMAND, ARGUMENTS... ], { Opt => Val ... } ) + +Execute the given C<COMMAND> in the same way as command() +does but always return a scalar string containing the first line +of the command's standard output. + +=cut + +sub command_oneline { + my ($fh, $ctx) = command_output_pipe(@_); + + my $line = <$fh>; + defined $line and chomp $line; + try { + _cmd_close($fh, $ctx); + } catch Git::Error::Command with { + # Pepper with the output: + my $E = shift; + $E->{'-outputref'} = \$line; + throw $E; + }; + return $line; +} + + +=item command_output_pipe ( COMMAND [, ARGUMENTS... ] ) + +=item command_output_pipe ( [ COMMAND, ARGUMENTS... ], { Opt => Val ... } ) + +Execute the given C<COMMAND> in the same way as command() +does but return a pipe filehandle from which the command output can be +read. + +The function can return C<($pipe, $ctx)> in array context. +See C<command_close_pipe()> for details. + +=cut + +sub command_output_pipe { + _command_common_pipe('-|', @_); +} + + +=item command_input_pipe ( COMMAND [, ARGUMENTS... ] ) + +=item command_input_pipe ( [ COMMAND, ARGUMENTS... ], { Opt => Val ... } ) + +Execute the given C<COMMAND> in the same way as command_output_pipe() +does but return an input pipe filehandle instead; the command output +is not captured. + +The function can return C<($pipe, $ctx)> in array context. +See C<command_close_pipe()> for details. + +=cut + +sub command_input_pipe { + _command_common_pipe('|-', @_); +} + + +=item command_close_pipe ( PIPE [, CTX ] ) + +Close the C<PIPE> as returned from C<command_*_pipe()>, checking +whether the command finished successfully. The optional C<CTX> argument +is required if you want to see the command name in the error message, +and it is the second value returned by C<command_*_pipe()> when +called in array context. The call idiom is: + + my ($fh, $ctx) = $r->command_output_pipe('status'); + while (<$fh>) { ... } + $r->command_close_pipe($fh, $ctx); + +Note that you should not rely on whatever actually is in C<CTX>; +currently it is simply the command name but in future the context might +have more complicated structure. + +=cut + +sub command_close_pipe { + my ($self, $fh, $ctx) = _maybe_self(@_); + $ctx ||= '<unknown>'; + _cmd_close($fh, $ctx); +} + + +=item command_noisy ( COMMAND [, ARGUMENTS... ] ) + +Execute the given C<COMMAND> in the same way as command() does but do not +capture the command output - the standard output is not redirected and goes +to the standard output of the caller application. + +While the method is called command_noisy(), you might want to as well use +it for the most silent Git commands which you know will never pollute your +stdout but you want to avoid the overhead of the pipe setup when calling them. + +The function returns only after the command has finished running. + +=cut + +sub command_noisy { + my ($self, $cmd, @args) = _maybe_self(@_); + _check_valid_cmd($cmd); + + my $pid = fork; + if (not defined $pid) { + throw Error::Simple("fork failed: $!"); + } elsif ($pid == 0) { + _cmd_exec($self, $cmd, @args); + } + if (waitpid($pid, 0) > 0 and $?>>8 != 0) { + throw Git::Error::Command(join(' ', $cmd, @args), $? >> 8); + } +} + + +=item version () + +Return the Git version in use. + +=cut + +sub version { + my $verstr = command_oneline('--version'); + $verstr =~ s/^git version //; + $verstr; +} + + +=item exec_path () + +Return path to the Git sub-command executables (the same as +C<git --exec-path>). Useful mostly only internally. + +=cut + +sub exec_path { command_oneline('--exec-path') } + + +=item repo_path () + +Return path to the git repository. Must be called on a repository instance. + +=cut + +sub repo_path { $_[0]->{opts}->{Repository} } + + +=item wc_path () + +Return path to the working copy. Must be called on a repository instance. + +=cut + +sub wc_path { $_[0]->{opts}->{WorkingCopy} } + + +=item wc_subdir () + +Return path to the subdirectory inside of a working copy. Must be called +on a repository instance. + +=cut + +sub wc_subdir { $_[0]->{opts}->{WorkingSubdir} ||= '' } + + +=item wc_chdir ( SUBDIR ) + +Change the working copy subdirectory to work within. The C<SUBDIR> is +relative to the working copy root directory (not the current subdirectory). +Must be called on a repository instance attached to a working copy +and the directory must exist. + +=cut + +sub wc_chdir { + my ($self, $subdir) = @_; + $self->wc_path() + or throw Error::Simple("bare repository"); + + -d $self->wc_path().'/'.$subdir + or throw Error::Simple("subdir not found: $!"); + # Of course we will not "hold" the subdirectory so anyone + # can delete it now and we will never know. But at least we tried. + + $self->{opts}->{WorkingSubdir} = $subdir; +} + + +=item config ( VARIABLE ) + +Retrieve the configuration C<VARIABLE> in the same manner as C<config> +does. In scalar context requires the variable to be set only one time +(exception is thrown otherwise), in array context returns allows the +variable to be set multiple times and returns all the values. + +Must be called on a repository instance. + +This currently wraps command('config') so it is not so fast. + +=cut + +sub config { + my ($self, $var) = @_; + $self->repo_path() + or throw Error::Simple("not a repository"); + + try { + if (wantarray) { + return $self->command('config', '--get-all', $var); + } else { + return $self->command_oneline('config', '--get', $var); + } + } catch Git::Error::Command with { + my $E = shift; + if ($E->value() == 1) { + # Key not found. + return undef; + } else { + throw $E; + } + }; +} + + +=item ident ( TYPE | IDENTSTR ) + +=item ident_person ( TYPE | IDENTSTR | IDENTARRAY ) + +This suite of functions retrieves and parses ident information, as stored +in the commit and tag objects or produced by C<var GIT_type_IDENT> (thus +C<TYPE> can be either I<author> or I<committer>; case is insignificant). + +The C<ident> method retrieves the ident information from C<git-var> +and either returns it as a scalar string or as an array with the fields parsed. +Alternatively, it can take a prepared ident string (e.g. from the commit +object) and just parse it. + +C<ident_person> returns the person part of the ident - name and email; +it can take the same arguments as C<ident> or the array returned by C<ident>. + +The synopsis is like: + + my ($name, $email, $time_tz) = ident('author'); + "$name <$email>" eq ident_person('author'); + "$name <$email>" eq ident_person($name); + $time_tz =~ /^\d+ [+-]\d{4}$/; + +Both methods must be called on a repository instance. + +=cut + +sub ident { + my ($self, $type) = @_; + my $identstr; + if (lc $type eq lc 'committer' or lc $type eq lc 'author') { + $identstr = $self->command_oneline('var', 'GIT_'.uc($type).'_IDENT'); + } else { + $identstr = $type; + } + if (wantarray) { + return $identstr =~ /^(.*) <(.*)> (\d+ [+-]\d{4})$/; + } else { + return $identstr; + } +} + +sub ident_person { + my ($self, @ident) = @_; + $#ident == 0 and @ident = $self->ident($ident[0]); + return "$ident[0] <$ident[1]>"; +} + + +=item hash_object ( TYPE, FILENAME ) + +Compute the SHA1 object id of the given C<FILENAME> (or data waiting in +C<FILEHANDLE>) considering it is of the C<TYPE> object type (C<blob>, +C<commit>, C<tree>). + +The method can be called without any instance or on a specified Git repository, +it makes zero difference. + +The function returns the SHA1 hash. + +=cut + +# TODO: Support for passing FILEHANDLE instead of FILENAME +sub hash_object { + my ($self, $type, $file) = _maybe_self(@_); + command_oneline('hash-object', '-t', $type, $file); +} + + + +=back + +=head1 ERROR HANDLING + +All functions are supposed to throw Perl exceptions in case of errors. +See the L<Error> module on how to catch those. Most exceptions are mere +L<Error::Simple> instances. + +However, the C<command()>, C<command_oneline()> and C<command_noisy()> +functions suite can throw C<Git::Error::Command> exceptions as well: those are +thrown when the external command returns an error code and contain the error +code as well as access to the captured command's output. The exception class +provides the usual C<stringify> and C<value> (command's exit code) methods and +in addition also a C<cmd_output> method that returns either an array or a +string with the captured command output (depending on the original function +call context; C<command_noisy()> returns C<undef>) and $<cmdline> which +returns the command and its arguments (but without proper quoting). + +Note that the C<command_*_pipe()> functions cannot throw this exception since +it has no idea whether the command failed or not. You will only find out +at the time you C<close> the pipe; if you want to have that automated, +use C<command_close_pipe()>, which can throw the exception. + +=cut + +{ + package Git::Error::Command; + + @Git::Error::Command::ISA = qw(Error); + + sub new { + my $self = shift; + my $cmdline = '' . shift; + my $value = 0 + shift; + my $outputref = shift; + my(@args) = (); + + local $Error::Depth = $Error::Depth + 1; + + push(@args, '-cmdline', $cmdline); + push(@args, '-value', $value); + push(@args, '-outputref', $outputref); + + $self->SUPER::new(-text => 'command returned error', @args); + } + + sub stringify { + my $self = shift; + my $text = $self->SUPER::stringify; + $self->cmdline() . ': ' . $text . ': ' . $self->value() . "\n"; + } + + sub cmdline { + my $self = shift; + $self->{'-cmdline'}; + } + + sub cmd_output { + my $self = shift; + my $ref = $self->{'-outputref'}; + defined $ref or undef; + if (ref $ref eq 'ARRAY') { + return @$ref; + } else { # SCALAR + return $$ref; + } + } +} + +=over 4 + +=item git_cmd_try { CODE } ERRMSG + +This magical statement will automatically catch any C<Git::Error::Command> +exceptions thrown by C<CODE> and make your program die with C<ERRMSG> +on its lips; the message will have %s substituted for the command line +and %d for the exit status. This statement is useful mostly for producing +more user-friendly error messages. + +In case of no exception caught the statement returns C<CODE>'s return value. + +Note that this is the only auto-exported function. + +=cut + +sub git_cmd_try(&$) { + my ($code, $errmsg) = @_; + my @result; + my $err; + my $array = wantarray; + try { + if ($array) { + @result = &$code; + } else { + $result[0] = &$code; + } + } catch Git::Error::Command with { + my $E = shift; + $err = $errmsg; + $err =~ s/\%s/$E->cmdline()/ge; + $err =~ s/\%d/$E->value()/ge; + # We can't croak here since Error.pm would mangle + # that to Error::Simple. + }; + $err and croak $err; + return $array ? @result : $result[0]; +} + + +=back + +=head1 COPYRIGHT + +Copyright 2006 by Petr Baudis E<lt>pasky@suse.czE<gt>. + +This module is free software; it may be used, copied, modified +and distributed under the terms of the GNU General Public Licence, +either version 2, or (at your option) any later version. + +=cut + + +# Take raw method argument list and return ($obj, @args) in case +# the method was called upon an instance and (undef, @args) if +# it was called directly. +sub _maybe_self { + # This breaks inheritance. Oh well. + ref $_[0] eq 'Git' ? @_ : (undef, @_); +} + +# Check if the command id is something reasonable. +sub _check_valid_cmd { + my ($cmd) = @_; + $cmd =~ /^[a-z0-9A-Z_-]+$/ or throw Error::Simple("bad command: $cmd"); +} + +# Common backend for the pipe creators. +sub _command_common_pipe { + my $direction = shift; + my ($self, @p) = _maybe_self(@_); + my (%opts, $cmd, @args); + if (ref $p[0]) { + ($cmd, @args) = @{shift @p}; + %opts = ref $p[0] ? %{$p[0]} : @p; + } else { + ($cmd, @args) = @p; + } + _check_valid_cmd($cmd); + + my $fh; + if ($^O eq 'MSWin32') { + # ActiveState Perl + #defined $opts{STDERR} and + # warn 'ignoring STDERR option - running w/ ActiveState'; + $direction eq '-|' or + die 'input pipe for ActiveState not implemented'; + # the strange construction with *ACPIPE is just to + # explain the tie below that we want to bind to + # a handle class, not scalar. It is not known if + # it is something specific to ActiveState Perl or + # just a Perl quirk. + tie (*ACPIPE, 'Git::activestate_pipe', $cmd, @args); + $fh = *ACPIPE; + + } else { + my $pid = open($fh, $direction); + if (not defined $pid) { + throw Error::Simple("open failed: $!"); + } elsif ($pid == 0) { + if (defined $opts{STDERR}) { + close STDERR; + } + if ($opts{STDERR}) { + open (STDERR, '>&', $opts{STDERR}) + or die "dup failed: $!"; + } + _cmd_exec($self, $cmd, @args); + } + } + return wantarray ? ($fh, join(' ', $cmd, @args)) : $fh; +} + +# When already in the subprocess, set up the appropriate state +# for the given repository and execute the git command. +sub _cmd_exec { + my ($self, @args) = @_; + if ($self) { + $self->repo_path() and $ENV{'GIT_DIR'} = $self->repo_path(); + $self->wc_path() and chdir($self->wc_path()); + $self->wc_subdir() and chdir($self->wc_subdir()); + } + _execv_git_cmd(@args); + die "exec failed: $!"; +} + +# Execute the given Git command ($_[0]) with arguments ($_[1..]) +# by searching for it at proper places. +sub _execv_git_cmd { exec('git', @_); } + +# Close pipe to a subprocess. +sub _cmd_close { + my ($fh, $ctx) = @_; + if (not close $fh) { + if ($!) { + # It's just close, no point in fatalities + carp "error closing pipe: $!"; + } elsif ($? >> 8) { + # The caller should pepper this. + throw Git::Error::Command($ctx, $? >> 8); + } + # else we might e.g. closed a live stream; the command + # dying of SIGPIPE would drive us here. + } +} + + +sub DESTROY { } + + +# Pipe implementation for ActiveState Perl. + +package Git::activestate_pipe; +use strict; + +sub TIEHANDLE { + my ($class, @params) = @_; + # FIXME: This is probably horrible idea and the thing will explode + # at the moment you give it arguments that require some quoting, + # but I have no ActiveState clue... --pasky + # Let's just hope ActiveState Perl does at least the quoting + # correctly. + my @data = qx{git @params}; + bless { i => 0, data => \@data }, $class; +} + +sub READLINE { + my $self = shift; + if ($self->{i} >= scalar @{$self->{data}}) { + return undef; + } + return $self->{'data'}->[ $self->{i}++ ]; +} + +sub CLOSE { + my $self = shift; + delete $self->{data}; + delete $self->{i}; +} + +sub EOF { + my $self = shift; + return ($self->{i} >= scalar @{$self->{data}}); +} + + +1; # Famous last words |