[pve-devel] [PATCH common v2 7/9] cli: allow specifying sub commands through $cmddef

[Wolfgang Bumiller]

On Mon, Dec 18, 2017 at 10:21:41AM +0100, Thomas Lamprecht wrote:
> allow to use sub commands alá
>  # pveum user add
> 
> The new resolve_cmd traverses $cmddef, resolves one level of aliases
> and returns the respective sub command, its cmddef, arguments and if
> it was expanded (e.g., pveum u d ... => pveum user delete ...) which
> allows quite easy integration in the usage/synopsis generator, bash
> completion helper and command handler.
> 
> Signed-off-by: Thomas Lamprecht <t.lamprecht at proxmox.com>
> ---
>  src/PVE/CLIHandler.pm | 101 +++++++++++++++++++++++++++++++++++++++++---------
>  1 file changed, 83 insertions(+), 18 deletions(-)
> 
> diff --git a/src/PVE/CLIHandler.pm b/src/PVE/CLIHandler.pm
> index 7d0804d..996ddfd 100644
> --- a/src/PVE/CLIHandler.pm
> +++ b/src/PVE/CLIHandler.pm
> @@ -36,10 +36,54 @@ my $expand_command_name = sub {
>      return $cmd;
>  };
>  
> -my $complete_command_names = sub {
> -    return [ sort keys %$cmddef ];
> +my $get_commands = sub {
> +    my $def = shift // die "no command definition passed!";
> +    return [ grep { !(ref($def->{$_}) eq 'HASH' && defined($def->{$_}->{alias})) } sort keys %$def ];
>  };
>  
> +my $complete_command_names = sub { $get_commands->($cmddef) };
> +
> +# traverses the command definition using the $argv array, resolving one level
> +# of aliases.
> +# Returns the matching (sub) command and its definition, and argument array for
> +# this (sub) command and a hash where we marked which (sub) commands got
> +# expanded (e.g. st => status) while traversing
> +sub resolve_cmd {
> +    my ($argv, $is_alias) = @_;
> +
> +    my ($def, $cmd) = ($cmddef, $argv);
> +
> +    if (ref($argv) eq 'ARRAY') {
> +	my $expanded = {};
> +	my $argc = scalar(@$argv) - 1;

Bad name, this is the last index, not the count.

> +
> +	for my $i (0..$argc) {
> +	    $cmd = &$expand_command_name($def, $argv->[$i]);
> +	    $expanded->{$argv->[$i]} = $cmd if $cmd ne $argv->[$i];
> +	    last if !defined($def->{$cmd});
> +	    $def = $def->{$cmd};
> +
> +	    if (ref($def) eq 'ARRAY') {
> +		# could expand to a real command, rest of $argv are its arguments
> +		my $cmd_args = ($i < $argc) ? [ @$argv[$i+1..$argc] ] : [];

If you have a @list of size N, then @list[N+1..N] will give you an
empty list without warnings/errors already, so it should be enough to
just use $cmd_args = [ $argv->@[$i+1..$argc] ];

> +		return ($cmd, $def, $cmd_args, $expanded);
> +	    }
> +
> +	    if (defined($def->{alias})) {
> +		die "alias loop detected for '$cmd'" if $is_alias; # avoids cycles
> +		# replace aliased (sub)command with the expanded aliased command
> +		splice @$argv, $i, 1, split(/ +/, $def->{alias});
> +		return resolve_cmd($argv, 1);
> +	    }
> +	}
> +	# got either a special command (bashcomplete, verifyapi) or an unknown
> +	# one, just return first entry as cmd and the rest of $argv as cmd_arg
> +	my $cmd_args = ($argc >= 1) ? [ @$argv[1..$argc] ] : [];

Same here.

> +	return ($argv->[0], $def, $cmd_args, $expanded);
> +    }
> +    return ($cmd, $def);
> +}
> +
>  sub generate_usage_str {
>      my ($format, $cmd, $indent, $separator, $sortfunc) = @_;
>  
> @@ -53,8 +97,7 @@ sub generate_usage_str {
>      my $can_read_pass = $cli_handler_class->can('read_password');
>      my $can_str_param_fmap = $cli_handler_class->can('string_param_file_mapping');
>  
> -    my $def = $cmddef;
> -    $def = $def->{$cmd} if $cmd && ref($def}) eq 'HASH' && $def->{$cmd};
> +    my ($subcmd, $def) = resolve_cmd($cmd);

The initial call to $generate() below then still just gets $exename
passed as prefix but should then get "$exename $subcmd"? Otherwise the
first subcommand level is skipped in the 'USAGE:' line output.

>  
>      my $generate;
>      $generate = sub {
> @@ -74,6 +117,19 @@ sub generate_usage_str {
>  		                              $fixed_param, $format,
>  		                              $can_read_pass, $can_str_param_fmap);
>  		    $oldclass = $class;
> +
> +		} elsif (defined($def->{$cmd}->{alias}) && ($format eq 'asciidoc')) {
> +
> +		    $str .= "*$prefix $cmd*\n\nAn alias for '$exename $def->{$cmd}->{alias}'.\n\n";
> +
> +		} else {
> +		    next if $def->{$cmd}->{alias};
> +
> +		    my $substr = $generate->($indent, $separator, $def->{$cmd}, "$prefix $cmd");
> +		    if ($substr) {
> +			$substr .= $separator if $substr !~ /$separator{2}/;

The distance of the places where the $separator argument is hardcoded
warrants the use of \Q and \E. Also the fact that without quoting this
looks like accessing key '2' of a hash %separator ;-).

> +			$str .= $substr;
> +		    }
>  		}
>  
>  	    }
> @@ -185,21 +241,24 @@ sub print_usage_verbose {
>  }
>  
>  sub print_usage_short {
> -    my ($fd, $msg) = @_;
> +    my ($fd, $msg, $cmd) = @_;
>  
>      $assert_initialized->();
>  
>      print $fd "ERROR: $msg\n" if $msg;
>      print $fd "USAGE: $exename <COMMAND> [ARGS] [OPTIONS]\n";
>  
> -    print {$fd} generate_usage_str('short', undef, ' ' x 7, "\n", sub {
> +    print {$fd} generate_usage_str('short', $cmd, ' ' x 7, "\n", sub {
>  	my ($h) = @_;
>  	return sort {
>  	    if (ref($h->{$a}) eq 'ARRAY' && ref($h->{$b}) eq 'ARRAY') {
>  		# $a and $b are both real commands order them by their class
>  		return $h->{$a}->[0] cmp $h->{$b}->[0];
> +	    } elsif (ref($h->{$a}) eq 'ARRAY' xor ref($h->{$b}) eq 'ARRAY') {
> +		# real command and subcommand mixed, put sub commands first
> +		return ref($h->{$b}) eq 'ARRAY' ? -1 : 1;
>  	    } else {
> -		# both are from the same class
> +		# both are either from the same class or subcommands
>  		return $a cmp $b;
>  	    }
>  	} keys %$h;
> @@ -228,13 +287,17 @@ my $print_bash_completion = sub {
>  
>      my ($cmd, $def) = ($simple_cmd, $cmddef);
>      if (!$simple_cmd) {
> -	if (!scalar(@$args)) {
> -	    &$print_result(keys %$def);
> +	($cmd, $def, $args, my $expaned) = resolve_cmd($args);
> +
> +	if (ref($def) eq 'HASH') {
> +	    &$print_result(@{$get_commands->($def)});
> +	    return;
> +	}
> +	if (my $expanded_cmd = $expaned->{$cur}) {
> +	    print "$expanded_cmd\n";
>  	    return;
>  	}
> -	$cmd = $args->[0];
>      }
> -    $def = $def->{$cmddef};
>      return if !$def;
>  
>      my $pos = scalar(@$args) - 1;
> @@ -374,8 +437,9 @@ my $handle_cmd  = sub {
>  
>      $cmddef->{help} = [ __PACKAGE__, 'help', ['cmd'] ];
>  
> +    my $cmd_str = join(' ', @$args);
> +    my ($cmd, $def, $cmd_args) = resolve_cmd($args);
>  
> -    my $cmd = shift @$args;
>      $abort->("no command specified") if !$cmd;
>  
>      # call verifyapi before setup_environment(), don't execute any real code in
> @@ -388,19 +452,20 @@ my $handle_cmd  = sub {
>      $cli_handler_class->setup_environment();
>  
>      if ($cmd eq 'bashcomplete') {
> -	&$print_bash_completion(undef, @$args);
> +	&$print_bash_completion(undef, @$cmd_args);
>  	return;
>      }
>  
> +    # checked special commands, if def is still a hash we got an incomplete sub command
> +    $abort->("incomplete command '$exename $cmd_str'") if ref($def) eq 'HASH';
> +
>      &$preparefunc() if $preparefunc;
>  
> -    $cmd = &$expand_command_name($cmddef, $cmd);
> -
>      my ($class, $name, $arg_param, $uri_param, $outsub) = @{$cmddef->{$cmd} || []};
> -    $abort->("unknown command '$cmd'") if !$class;
> +    $abort->("unknown command '$cmd_str'") if !$class;
>  
> -    my $prefix = "$exename $cmd";
> -    my $res = $class->cli_handler($prefix, $name, \@ARGV, $arg_param, $uri_param, $pwcallback, $stringfilemap);
> +    my $prefix = "$exename $cmd_str";
> +    my $res = $class->cli_handler($prefix, $name, $cmd_args, $arg_param, $uri_param, $pwcallback, $stringfilemap);
>  
>      &$outsub($res) if $outsub;
>  };
> -- 
> 2.11.0