Dpkg::Index: new module

This module represents an ordered set of Dpkg::Control objects.
It ensures uniqueness for objects based on a customisable key.

scripts/Dpkg/Index.pm

@@ -0,0 +1,371 @@
+# Copyright © 2009 Raphaël Hertzog <hertzog@debian.org>
+#
+# This program is free software; you can redistribute it and/or modify
+# it under the terms of the GNU General Public License as published by
+# the Free Software Foundation; either version 2 of the License, or
+# (at your option) any later version.
+#
+# This program is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+# GNU General Public License for more details.
+#
+# You should have received a copy of the GNU General Public License along
+# with this program; if not, write to the Free Software Foundation, Inc.,
+# 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
+
+package Dpkg::Index;
+
+use strict;
+use warnings;
+
+use Dpkg::Gettext;
+use Dpkg::ErrorHandling;
+use Dpkg::Control;
+use Dpkg::Source::CompressedFile;
+
+use overload
+    '@{}' => sub { return $_[0]->{'order'} },
+    '""' => sub { return $_[0]->output() },
+    fallback => 1;
+
+=head1 NAME
+
+Dpkg::Index - generic index of control information
+
+=head1 DESCRIPTION
+
+This object represent a set of Dpkg::Control objects.
+
+=head1 FUNCTIONS
+
+=over 4
+
+=item my $index = Dpkg::Index->new(%opts)
+
+Creates a new empty index. See set_options() for more details.
+
+=cut
+
+sub new {
+    my ($this, %opts) = @_;
+    my $class = ref($this) || $this;
+
+    my $self = {
+	items => {},
+	order => [],
+	get_key_func => sub { return $_[0]->{Package} },
+	type => CTRL_UNKNOWN,
+    };
+    bless $self, $class;
+    $self->set_options(%opts);
+    if (exists $opts{'load'}) {
+	$self->load($opts{'load'});
+    }
+
+    return $self;
+}
+
+=item $index->set_options(%opts)
+
+The "type" option is checked first to define default values for other
+options. Here are the relevant options: "get_key_func" is a function
+returning a key for the item passed in parameters. The index can only
+contain one item with a given key. The function used depend on the
+type: for CTRL_INFO_PKG, CTRL_INDEX_SRC, CTRL_INDEX_PKG and CTRL_PKG_DEB
+it's simply the Package field; for CTRL_PKG_SRC and CTRL_INFO_SRC, it's
+the Source field; for CTRL_CHANGELOG it's the Source and the Version
+fields (concatenated with an intermediary "_"); for CTRL_FILE_CHANGES it's
+the Source, Version and Architecture fields (concatenated with "_");
+for CTRL_FILE_VENDOR it's the Vendor field; for CTRL_FILE_STATUS it's the
+Package and Architecture fields (concatenated with "_"). Otherwise it's
+the Package field by default.
+
+=cut
+
+sub set_options {
+    my ($self, %opts) = @_;
+
+    # Default values based on type
+    if (exists $opts{'type'}) {
+        my $t = $opts{'type'};
+        if ($t == CTRL_INFO_PKG or $t == CTRL_INDEX_SRC or
+	         $t == CTRL_INDEX_PKG or $t == CTRL_PKG_DEB) {
+	    $self->{get_key_func} = sub { return $_[0]->{Package}; };
+        } elsif ($t == CTRL_PKG_SRC or $t == CTRL_INFO_SRC) {
+	    $self->{get_key_func} = sub { return $_[0]->{Source}; };
+        } elsif ($t == CTRL_CHANGELOG) {
+	    $self->{get_key_func} = sub {
+		return $_[0]->{Source} . "_" . $_[0]->{Version};
+	    };
+        } elsif ($t == CTRL_FILE_CHANGES) {
+	    $self->{get_key_func} = sub {
+		return $_[0]->{Source} . "_" . $_[0]->{Version} . "_" .
+		       $_[0]->{Architecture};
+	    };
+        } elsif ($t == CTRL_FILE_VENDOR) {
+	    $self->{get_key_func} = sub { return $_[0]->{Vendor}; };
+        } elsif ($t == CTRL_FILE_STATUS) {
+	    $self->{get_key_func} = sub {
+		return $_[0]->{Package} . "_" . $_[0]->{Architecture};
+	    };
+        }
+    }
+
+    # Options set by the user override default values
+    $self->{$_} = $opts{$_} foreach keys %opts;
+}
+
+=item $index->get_type()
+
+Returns the type of control information stored. See the type parameter
+set during new().
+
+=cut
+
+sub get_type {
+    my ($self) = @_;
+    return $self->{'type'};
+}
+
+=item $index->add($item, [$key])
+
+Add a new item in the index. If the $key parameter is omitted, the key
+will be generated with the get_key_func function (see set_options() for
+details).
+
+=cut
+
+sub add {
+    my ($self, $item, $key) = @_;
+    unless (defined $key) {
+	$key = $self->{'get_key_func'}($item);
+    }
+    if (not exists $self->{'items'}{$key}) {
+	push @{$self->{'order'}}, $key;
+    }
+    $self->{'items'}{$key} = $item;
+}
+
+=item $index->load($file)
+
+Reads the file and creates all items parsed. Returns the number of items
+parsed. Handles compressed files transparently based on their extensions.
+
+=cut
+
+sub load {
+    my ($self, $file) = @_;
+    my $cf = Dpkg::Source::CompressedFile->new(filename => $file);
+    my $fh = $cf->open_for_read();
+    my $res = $self->parse($fh, $file);
+    $cf->cleanup_after_open();
+    close($fh) || syserr(_g("cannot close %s"), $file);
+    return $res;
+}
+
+=item $index->parse($fh, $desc)
+
+Reads the filehandle and creates all items parsed. Returns the number of
+items parsed.
+
+=cut
+
+sub parse {
+    my ($self, $fh, $desc) = @_;
+    my $item = $self->new_item();
+    my $i = 0;
+    while ($item->parse_fh($fh, $desc)) {
+	$self->add($item);
+	$item = $self->new_item();
+	$i++;
+    }
+    return $i;
+}
+
+=item $index->save($file)
+
+Writes the content of the index in a file. Auto-compresses files
+based on their extensions.
+
+=cut
+
+sub save {
+    my ($self, $file) = @_;
+    my $cf = Dpkg::Source::CompressedFile->new(filename => $file);
+    my $fh = $cf->open_for_write();
+    $self->output($fh);
+    $cf->cleanup_after_open();
+    close($fh) || syserr(_g("cannot close %s"), $file);
+}
+
+=item my $item = $index->new_item()
+
+Creates a new item. Mainly useful for derived objects that would want
+to override this method to return something else than a Dpkg::Control
+object.
+
+=cut
+
+sub new_item {
+    my ($self) = @_;
+    return Dpkg::Control->new(type => $self->{'type'});
+}
+
+=item my $item = $index->get_by_key($key)
+
+Returns the item identified by $key or undef.
+
+=cut
+
+sub get_by_key {
+    my ($self, $key) = @_;
+    return $self->{'items'}{$key} if exists $self->{'items'}{$key};
+    return undef;
+}
+
+=item my @keys = $index->get_keys(%criteria)
+
+Returns the keys of items that matches all the criteria. The key of the
+%criteria hash is a field name and the value is either a regexp that needs
+to match the field value, or a reference to a function that must return
+true and that receives the field value as single parameter, or a scalar
+that must be equal to the field value.
+
+=cut
+
+sub get_keys {
+    my ($self, %crit) = @_;
+    my @selected = @{$self->{order}};
+    foreach my $s_crit (keys %crit) { # search criteria
+	if (ref($crit{$s_crit}) eq "Regexp") {
+	    @selected = grep {
+		$self->{'items'}{$_}{$s_crit} =~ $crit{$s_crit}
+	    } @selected;
+	} elsif (ref($crit{$s_crit}) eq "CODE") {
+	    @selected = grep {
+		&{$crit{$s_crit}}($self->{'items'}{$_}{$s_crit});
+	    } @selected;
+	} else {
+	    @selected = grep {
+		$self->{'items'}{$_}{$s_crit} eq $crit{$s_crit}
+	    } @selected;
+	}
+    }
+    return @selected;
+}
+
+=item my @items = $index->get(%criteria)
+
+Returns all the items that matches all the criteria.
+
+=cut
+
+sub get {
+    my ($self, %crit) = @_;
+    return map { $self->{'items'}{$_} } $self->get_by_keys(%crit);
+}
+
+=item $index->remove_by_key($key)
+
+Remove the item identified by the given key.
+
+=cut
+
+sub remove_by_key {
+    my ($self, $key) = @_;
+    @{$self->{'order'}} = grep { $_ ne $key } @{$self->{'order'}};
+    return delete $self->{'items'}{$key};
+}
+
+=item my @items = $index->remove(%criteria)
+
+Returns and removes all the items that matches all the criteria.
+
+=cut
+
+sub remove {
+    my ($self, %crit) = @_;
+    my @keys = $self->get_by_keys(%crit);
+    my (%keys, @ret);
+    foreach my $key (@keys) {
+	$keys{$key} = 1;
+	push @ret, $self->{'items'}{$key} if defined wantarray;
+	delete $self->{'items'}{$key};
+    }
+    @{$self->{'order'}} = grep { not exists $keys{$_} } @{$self->{'order'}};
+    return @ret;
+}
+
+=item $index->merge($other_index, %opts)
+
+Merge the entries of the other index. While merging, the keys of the merged
+index are used, they are not re-computed (unless you have set the options
+"keep_keys" to "0"). It's your responsibility to ensure that they have been
+computed with the same function.
+
+=cut
+
+sub merge {
+    my ($self, $other, %opts) = @_;
+    $opts{'keep_keys'} = 1 unless exists $opts{'keep_keys'};
+    foreach my $key ($other->get_keys()) {
+	$self->add($other->get_by_key($key), $opts{'keep_keys'} ? $key : undef);
+    }
+}
+
+=item $index->sort(\&sortfunc)
+
+Sort the index with the given sort function. If no function is given, an
+alphabetic sort is done based on the keys. The sort function receives the
+items themselves as parameters and not the keys.
+
+=cut
+
+sub sort {
+    my ($self, $func) = @_;
+    if (defined $func) {
+	@{$self->{'order'}} = sort {
+	    &$func($self->{'items'}{$a}, $self->{'items'}{$b})
+	} @{$self->{'order'}};
+    } else {
+	@{$self->{'order'}} = sort @{$self->{'order'}};
+    }
+}
+
+=item my $str = $index->output()
+=item "$index"
+
+Get a string representation of the index. The Dpkg::Control objects are
+output in the order which they have been read or added except if the order
+hae been changed with sort().
+
+=item $index->output($fh)
+
+Print the string representation of the index to a filehandle.
+
+=cut
+
+sub output {
+    my ($self, $fh) = @_;
+    my $str = "";
+    foreach my $key ($self->get_keys()) {
+	if (defined $fh) {
+	    print $fh $self->get_by_key($key) . "\n";
+	}
+	if (defined wantarray) {
+	    $str .= $self->get_by_key($key) . "\n";
+	}
+    }
+    return $str;
+}
+
+=back
+
+=head1 AUTHOR
+
+Raphaël Hertzog <hertzog@debian.org>.
+
+=cut
+
+1;

scripts/Makefile.am

@@ -102,6 +102,7 @@ nobase_dist_perllib_DATA = \
 	Dpkg/ErrorHandling.pm \
 	Dpkg/Exit.pm \
 	Dpkg/Gettext.pm \
+	Dpkg/Index.pm \
 	Dpkg/IPC.pm \
 	Dpkg/Path.pm \
 	Dpkg/Shlibs.pm \

scripts/po/POTFILES.in

@@ -25,6 +25,7 @@ scripts/Dpkg/Control/Hash.pm
 scripts/Dpkg/Control/Types.pm
 scripts/Dpkg/Deps.pm
 scripts/Dpkg/ErrorHandling.pm
+scripts/Dpkg/Index.pm
 scripts/Dpkg/IPC.pm
 scripts/Dpkg/Shlibs.pm
 scripts/Dpkg/Shlibs/Objdump.pm