lei: start working on bash completion

[public-inbox.git] / lib / PublicInbox / LEI.pm

diff --git a/lib/PublicInbox/LEI.pm b/lib/PublicInbox/LEI.pm
index fd412324be3b9d3eefbc73f983a0e11938fcd79f..7004e9d72ed634dddf3dff99fd1b9b8024870c61 100644 (file)
--- a/lib/PublicInbox/LEI.pm
+++ b/lib/PublicInbox/LEI.pm
@@ -132,7 +132,11 @@ our %CMD = ( # sorted in order of importance/use:
 
 'reorder-local-store-and-break-history' => [ '[REFNAME]',
        'rewrite git history in an attempt to improve compression',
-       'gc!' ]
+       'gc!' ],
+
+# internal commands are prefixed with '_'
+'_complete' => [ '[...]', 'internal shell completion helper',
+               pass_through('everything') ],
 ); # @CMD
 
 # switch descriptions, try to keep consistent across commands
@@ -209,6 +213,10 @@ my %OPTDESC = (
        'unset matching NAME, may be specified multiple times'],
 ); # %OPTDESC
 
+my %CONFIG_KEYS = (
+       'leistore.dir' => 'top-level storage location',
+);
+
 sub x_it ($$) { # pronounced "exit"
        my ($self, $code) = @_;
        if (my $sig = ($code & 127)) {
@@ -223,6 +231,8 @@ sub x_it ($$) { # pronounced "exit"
        }
 }
 
+sub puts ($;@) { print { shift->{1} } map { "$_\n" } @_ }
+
 sub emit {
        my ($self, $channel) = @_; # $buf = $_[2]
        print { $self->{$channel} } $_[2] or die "print FD[$channel]: $!";
@@ -522,6 +532,55 @@ sub lei_daemon_env {
 
 sub lei_help { _help($_[0]) }
 
+# Shell completion helper.  Used by lei-completion.bash and hopefully
+# other shells.  Try to do as much here as possible to avoid redundancy
+# and improve maintainability.
+sub lei__complete {
+       my ($self, @argv) = @_; # argv = qw(lei and any other args...)
+       shift @argv; # ignore "lei", the entire command is sent
+       @argv or return puts $self, grep(!/^_/, keys %CMD);
+       my $cmd = shift @argv;
+       my $info = $CMD{$cmd} // do { # filter matching commands
+               @argv or puts $self, grep(/\A\Q$cmd\E/, keys %CMD);
+               return;
+       };
+       my ($proto, undef, @spec) = @$info;
+       my $cur = pop @argv;
+       my $re = defined($cur) ? qr/\A\Q$cur\E/ : qr/./;
+       if (substr($cur // '-', 0, 1) eq '-') { # --switches
+               # gross special case since the only git-config options
+               # Consider moving to a table if we need more special cases
+               # we use Getopt::Long for are the ones we reject, so these
+               # are the ones we don't reject:
+               if ($cmd eq 'config') {
+                       puts $self, grep(/$re/, keys %CONFIG_KEYS);
+                       @spec = qw(add z|null get get-all unset unset-all
+                               replace-all get-urlmatch
+                               remove-section rename-section
+                               name-only list|l edit|e
+                               get-color-name get-colorbool);
+                       # fall-through
+               }
+               # TODO: arg support
+               puts $self, grep(/$re/, map { # generate short/long names
+                       my $eq = '';
+                       if (s/=.+\z//) { # required arg, e.g. output|o=i
+                               $eq = '=';
+                       } elsif (s/:.+\z//) { # optional arg, e.g. mid:s
+                       } else { # negation: solve! => no-solve|solve
+                               s/\A(.+)!\z/no-$1|$1/;
+                       }
+                       map {
+                               length > 1 ? "--$_$eq" : "-$_"
+                       } split(/\|/, $_, -1) # help|h
+               } grep { !ref } @spec); # filter out $GLP_PASS ref
+       } elsif ($cmd eq 'config' && !@argv && !$CONFIG_KEYS{$cur}) {
+               puts $self, grep(/$re/, keys %CONFIG_KEYS);
+       }
+       # TODO: URLs, pathnames, OIDs, MIDs, etc...  See optparse() for
+       # proto parsing.
+}
+
 sub reap_exec { # dwaitpid callback
        my ($self, $pid) = @_;
        x_it($self, $?);