File Coverage

blib/lib/Complete/Bash.pm

Criterion	Covered	Total	%
statement	168	227	74.0
branch	100	162	61.7
condition	54	85	63.5
subroutine	18	19	94.7
pod	4	4	100.0
total	344	497	69.2

package Complete::Bash;

our $AUTHORITY = 'cpan:PERLANCAR'; # AUTHORITY
our $DATE = '2021-07-24'; # DATE
our $DIST = 'Complete-Bash'; # DIST
our $VERSION = '0.336'; # VERSION

use 5.010001;
use strict;
use warnings;
use Log::ger;

require Exporter;
our @ISA = qw(Exporter);
our @EXPORT_OK = qw(
                       point
                       parse_cmdline
                       join_wordbreak_words
                       format_completion
               );

our %SPEC;

$SPEC{':package'} = {
    v => 1.1,
    summary => 'Completion routines for bash shell',
};

sub _expand_tilde {
    my ($user, $slash) = @_;
    my @ent;
    if (length $user) {
        @ent = getpwnam($user);
    } else {
        @ent = getpwuid($>);
        $user = $ent[0];
    }
    return $ent[7] . $slash if @ent;
    "~$user$slash"; # return as-is when failed
}

sub _add_unquoted {
    no warnings 'uninitialized';

    my ($word, $is_cur_word, $after_ws) = @_;

    #say "D:add_unquoted word=$word is_cur_word=$is_cur_word after_ws=$after_ws";

    $word =~ s!^(~)(\w*)(/|\z) |  # 1) tilde  2) username  3) optional slash
               \\(.)           |  # 4) escaped char
               \$(\w+)            # 5) variable name
              !
                  $1 ? (not($after_ws) || $is_cur_word ? "$1$2$3" : _expand_tilde($2, $3)) :
                      $4 ? $4 :
                          ($is_cur_word ? "\$$5" : $ENV{$5})
                              !egx;
    $word;
}

sub _add_double_quoted {
    no warnings 'uninitialized';

    my ($word, $is_cur_word) = @_;

    $word =~ s!\\(.)           |  # 1) escaped char
               \$(\w+)            # 2) variable name
              !
                  $1 ? $1 :
                      ($is_cur_word ? "\$$2" : $ENV{$2})
                          !egx;
    $word;
}

sub _add_single_quoted {
    my $word = shift;
    $word =~ s/\\(.)/$1/g;
    $word;
}

$SPEC{point} = {
    v => 1.1,
    summary => 'Return line with point marked by a marker',
    description => <<'_',

This is a utility function useful for testing/debugging. `parse_cmdline()`
expects a command-line and a cursor position (`$line`, `$point`). This routine
expects `$line` with a marker character (by default it's the caret, `^`) and
return (`$line`, `$point`) to feed to `parse_cmdline()`.

Example:

    point("^foo") # => ("foo", 0)
    point("fo^o") # => ("foo", 2)

_
    args_as => 'array',
    args => {
        cmdline => {
            summary => 'Command-line which contains a marker character',
            schema => 'str*',
            pos => 0,
        },
        marker => {
            summary => 'Marker character',
            schema => ['str*', len=>1],
            default => '^',
            pos => 1,
        },
    },
    result_naked => 1,
};
sub point {
    my ($line, $marker) = @_;
    $marker //= '^';

    my $point = index($line, $marker);
    die "BUG: No marker '$marker' in line <$line>" unless $point >= 0;
    $line =~ s/\Q$marker\E//;
    ($line, $point);
}

$SPEC{parse_cmdline} = {
    v => 1.1,
    summary => 'Parse shell command-line for processing by completion routines',
    description => <<'_',

This function basically converts `COMP_LINE` (str) and `COMP_POINT` (int) into
something like (but not exactly the same as) `COMP_WORDS` (array) and
`COMP_CWORD` (int) that bash supplies to shell functions.

The differences with bash are (these differences are mostly for parsing
convenience for programs that use this routine; this comparison is made against
bash versions 4.2-4.3):

1) quotes and backslashes are stripped (bash's `COMP_WORDS` contains all the
   quotes and backslashes);

2) quoted phrase that contains spaces, or phrase that contains escaped spaces is
   parsed as a single word. For example:

    command "First argument" Second\ argument

   bash would split it as (represented as Perl):

    ["command", "\"First", "argument\"", "Second\\", "argument"]

   which is not very convenient. We parse it into:

    ["command", "First argument", "Second argument"]

3) variables are substituted with their values from environment variables except
   for the current word (`COMP_WORDS[COMP_CWORD]`) (bash does not perform
   variable substitution for `COMP_WORDS`). However, note that special shell
   variables that are not environment variables like `$0`, `$_`, `$IFS` will not
   be replaced correctly because bash does not export those variables for us.

4) tildes (`~`) are expanded with user's home directory except for the current
   word (bash does not perform tilde expansion for `COMP_WORDS`);

Caveats:

* Like bash, we group non-whitespace word-breaking characters into its own word.
  By default `COMP_WORDBREAKS` is:

    "'@><=;|&(:

  So if raw command-line is:

    command --foo=bar http://example.com:80 [e-mail] Foo::Bar

  then the parse result will be:

    ["command", "--foo", "=", "bar", "http", ":", "//example.com", ":", "80", "Foo", "::", "Bar"]

  which is annoying sometimes. But we follow bash here so we can more easily
  accept input from a joined `COMP_WORDS` if we write completion bash functions,
  e.g. (in the example, `foo` is a Perl script):

    _foo ()
    {
        local words=(${COMP_CWORDS[@]})
        # add things to words, etc
        local point=... # calculate the new point
        COMPREPLY=( `COMP_LINE="foo ${words[@]}" COMP_POINT=$point foo` )
    }

  To avoid these word-breaking characters to be split/grouped, we can escape
  them with backslash or quote them, e.g.:

    command "http://example.com:80" Foo\:\:Bar

  which bash will parse as:

    ["command", "\"http://example.com:80\"", "Foo\\:\\:Bar"]

  and we parse as:

    ["command", "http://example.com:80", "Foo::Bar"]

* Due to the way bash parses the command line (see above), the two below are
  equivalent:

    % cmd --foo=bar
    % cmd --foo = bar

Because they both expand to `['--foo', '=', 'bar']`. But obviously
 does not regard the two as equivalent.

_
    args_as => 'array',
    args => {
        cmdline => {
            summary => 'Command-line, defaults to COMP_LINE environment',
            schema => 'str*',
            pos => 0,
        },
        point => {
            summary => 'Point/position to complete in command-line, '.
                'defaults to COMP_POINT',
            schema => 'int*',
            pos => 1,
        },
        opts => {
            summary => 'Options',
            schema => 'hash*',
            description => <<'_',

Optional. Known options:

* `truncate_current_word` (bool). If set to 1, will truncate current word to the
  position of cursor, for example (`^` marks the position of cursor):
  `--vers^oo` to `--vers` instead of `--versoo`. This is more convenient when
  doing tab completion.

_
            schema => 'hash*',
            pos => 2,
        },
    },
    result => {
        schema => ['array*', len=>2],
        description => <<'_',

Return a 2-element array: `[$words, $cword]`. `$words` is array of str,
equivalent to `COMP_WORDS` provided by bash to shell functions. `$cword` is an
integer, roughly equivalent to `COMP_CWORD` provided by bash to shell functions.
The word to be completed is at `$words->[$cword]`.

Note that COMP_LINE includes the command name. If you want the command-line
arguments only (like in `@ARGV`), you need to strip the first element from
`$words` and reduce `$cword` by 1.


_
    },
    result_naked => 1,
    links => [
    ],
};
sub parse_cmdline {
    no warnings 'uninitialized';
    my ($line, $point, $opts) = @_;

    $line  //= $ENV{COMP_LINE};
    $point //= $ENV{COMP_POINT} // 0;

    die "$0: COMP_LINE not set, make sure this script is run under ".
        "bash completion (e.g. through complete -C)\n" unless defined $line;

    log_trace "[compbash] parse_cmdline(): input: line=<$line> point=<$point>"
        if $ENV{COMPLETE_BASH_TRACE};

    my @words;
    my $cword;
    my $pos = 0;
    my $pos_min_ws = 0;
    my $after_ws = 1; # XXX what does this variable mean?
    my $chunk;
    my $add_blank;
    my $is_cur_word;
    $line =~ s!(                                                         # 1) everything
                  (")((?: \\\\|\\"|[^"])*)(?:"|\z)(\s*)               |  #  2) open "  3) content  4) space after
                  (')((?: \\\\|\\'|[^'])*)(?:'|\z)(\s*)               |  #  5) open '  6) content  7) space after
                  ((?: \\\\|\\"|\\'|\\=|\\\s|[^"'@><=|&\(:\s])+)(\s*) |  #  8) unquoted word  9) space after
                  ([\@><=|&\(:]+) |                                      #  10) non-whitespace word-breaking characters
                  \s+
              )!
                  $pos += length($1);
                  #say "D: \$1=<$1> \$2=<$3> \$3=<$3> \$4=<$4> \$5=<$5> \$6=<$6> \$7=<$7> \$8=<$8> \$9=<$9> \$10=<$10>";
                  #say "D:<$1> pos=$pos, point=$point, cword=$cword, after_ws=$after_ws";

                  if ($2 || $5 || defined($8)) {
                      # double-quoted/single-quoted/unquoted chunk

                      if (not(defined $cword)) {
                          $pos_min_ws = $pos - length($2 ? $4 : $5 ? $7 : $9);
                          #say "D:pos_min_ws=$pos_min_ws";
                          if ($point <= $pos_min_ws) {
                              $cword = @words - ($after_ws ? 0 : 1);
                          } elsif ($point < $pos) {
                              $cword = @words + 1 - ($after_ws ? 0 : 1);
                              $add_blank = 1;
                          }
                      }

                      if ($after_ws) {
                          $is_cur_word = defined($cword) && $cword==@words;
                      } else {
                          $is_cur_word = defined($cword) && $cword==@words-1;
                      }
                      #say "D:is_cur_word=$is_cur_word";
                      $chunk =
                          $2 ? _add_double_quoted($3, $is_cur_word) :
                              $5 ? _add_single_quoted($6) :
                              _add_unquoted($8, $is_cur_word, $after_ws);
                      if ($opts && $opts->{truncate_current_word} &&
                              $is_cur_word && $pos > $point) {
                          $chunk = substr(
                              $chunk, 0, length($chunk)-($pos_min_ws-$point));
                          #say "D:truncating current word to <$chunk>";
                      }
                      if ($after_ws) {
                          push @words, $chunk;
                      } else {
                          $words[-1] .= $chunk;
                      }
                      if ($add_blank) {
                          push @words, '';
                          $add_blank = 0;
                      }
                      $after_ws = ($2 ? $4 : $5 ? $7 : $9) ? 1:0;

                  } elsif ($10) {
                      # non-whitespace word-breaking characters
                      push @words, $10;
                      $after_ws = 1;
                  } else {
                      # whitespace
                      $after_ws = 1;
                  }
    !egx;

    $cword //= @words;
    $words[$cword] //= '';

    log_trace "[compbash] parse_cmdline(): result: words=%s, cword=%s", \@words, $cword
        if $ENV{COMPLETE_BASH_TRACE};

    [\@words, $cword];
}

$SPEC{join_wordbreak_words} = {
    v => 1.1,
    summary => 'Post-process parse_cmdline() result by joining some words',
    description => <<'_',

`parse_cmdline()`, like bash, splits some characters that are considered as
word-breaking characters:

    "'@><=;|&(:

So if command-line is:

    command --module=Data::Dump [e-mail]

then they will be parsed as:

    ["command", "--module", "=", "Data", "::", "Dump", "bob", '@', "example.org"]

Normally in Perl applications, we want `:`, `@` to be part of word. So this
routine will convert the above into:

    ["command", "--module=Data::Dump", '[e-mail]']

_
};
sub join_wordbreak_words {
    my ($words, $cword) = @_;
    my $new_words = [];
    my $i = -1;
    while (++$i < @$words) {
        my $w = $words->[$i];
        if ($w =~ /\A[\@=:]+\z/) {
            if (@$new_words and $#$new_words != $cword) {
                $new_words->[-1] .= $w;
                $cword-- if $cword >= $i || $cword >= @$new_words;
            } else {
                push @$new_words, $w;
            }
            if ($i+1 < @$words) {
                $i++;
                $new_words->[-1] .= $words->[$i];
                $cword-- if $cword >= $i || $cword >= @$new_words;
            }
        } else {
            push @$new_words, $w;
        }
    }
    log_trace "[compbash] join_wordbreak_words(): result: words=%s, cword=%d", $new_words, $cword
        if $ENV{COMPLETE_BASH_TRACE};
    [$new_words, $cword];
}

sub _terminal_width {
    # XXX need to cache?
    if (eval { require Term::Size; 1 }) {
        my ($cols, undef) = Term::Size::chars(*STDOUT{IO});
        $cols // 80;
    } else {
        $ENV{COLUMNS} // 80;
    }
}

# given terminal width & number of columns, calculate column width
sub _column_width {
    my ($terminal_width, $num_columns) = @_;
    if (defined $num_columns && $num_columns > 0) {
        int( ($terminal_width - ($num_columns-1)*2) / $num_columns ) - 1;
    } else {
        undef;
    }
}

# given terminal width & column width, calculate number of columns
sub _num_columns {
    my ($terminal_width, $column_width) = @_;
    my $n = int( ($terminal_width+2) / ($column_width+2) );
    $n >= 1 ? $n : 1;
}

$SPEC{format_completion} = {
    v => 1.1,
    summary => 'Format completion for output (for shell)',
    description => <<'_',

Bash accepts completion reply in the form of one entry per line to STDOUT. Some
characters will need to be escaped. This function helps you do the formatting,
with some options.

This function accepts completion answer structure as described in the `Complete`
POD. Aside from `words`, this function also recognizes these keys:

_
    args_as => 'array',
    args => {
        completion => {
            summary => 'Completion answer structure',
            description => <<'_',

Either an array or hash. See function description for more details.

_
            schema=>['any*' => of => ['hash*', 'array*']],
            req=>1,
            pos=>0,
        },
        opts => {
            summary => 'Specify options',
            schema=>'hash*',
            pos=>1,
            description => <<'_',

Known options:

* as

  Either `string` (the default) or `array` (to return array of lines instead of
  the lines joined together). Returning array is useful if you are doing
  completion inside `Term::ReadLine`, for example, where the library expects an
  array.

* esc_mode

  Escaping mode for entries. Either `default` (most nonalphanumeric characters
  will be escaped), `shellvar` (like `default`, but dollar sign `$` will also be
  escaped, convenient when completing environment variables for example),
  `filename` (currently equals to `default`), `option` (currently equals to
  `default`), or `none` (no escaping will be done).

* word

  A workaround. String. For now, see source code for more details.

* show_summaries

  Whether to show item's summaries. Boolean, default is from
  COMPLETE_BASH_SHOW_SUMMARIES environment variable or 1.

  An answer item contain summary, which is a short description about the item,
  e.g.:

      [{word=>"-a"    , summary=>"Show hidden files"},
       {word=>"-l"    , summary=>"Show details"},
       {word=>"--sort", summary=>"Specify sort order"}],

  When summaries are not shown, user will just be seeing something like:

      -a
      -l
      --sort

  But when summaries are shown, user will see:

      -a         -- Show hidden files
      -l         -- Show details
      --sort     -- Specify sort order

  which is quite helpful.

* workaround_with_wordbreaks

  Boolean. Default is true. See source code for more details.

_

        },
    },
    result => {
        summary => 'Formatted string (or array, if `as` is set to `array`)',
        schema => ['any*' => of => ['str*', 'array*']],
    },
    result_naked => 1,
};
sub format_completion {
    my ($hcomp, $opts) = @_;

    $opts //= {};

    $hcomp = {words=>$hcomp} unless ref($hcomp) eq 'HASH';
    my $words    = $hcomp->{words};
    my $as       = $opts->{as} // 'string';
    # 'escmode' key is deprecated (Complete 0.11-) and will be removed later
    my $esc_mode = $opts->{esc_mode} // $ENV{COMPLETE_BASH_DEFAULT_ESC_MODE} //
        'default';
    my $path_sep = $hcomp->{path_sep};

    # we keep the original words (before formatted with summaries) when we want
    # to use fzf instead of passing to bash directly
    my @words;
    my @summaries;
    my @res;
    my $has_summary;

    my $code_return_message = sub {
        # display a message instead of list of words. we send " " (ASCII space)
        # which bash does not display, so we can display a line of message while
        # the user does not get the message as the completion. I've also tried
        # \000 to \037 instead of space (\040) but nothing works better.
        my $msg = shift;
        if ($msg =~ /\A /) {
            $msg =~ s/\A +//;
            $msg = " (empty message)" unless length $msg;
        }
        return (sprintf("%-"._terminal_width()."s", $msg), " ");
    };

  FORMAT_MESSAGE:
    # display a message instead of list of words. we send " " (ASCII space)
    # which bash does not display, so we can display a line of message while the
    # user does not get the message as the completion. I've also tried \000 to
    # \037 instead of space (\040) but nothing works better.
    if (defined $hcomp->{message}) {
        @res = $code_return_message->($hcomp->{message});
        goto RETURN_RES;
    }

  WORKAROUND_PREVENT_BASH_FROM_INSERTING_SPACE:
    {
        last unless @$words == 1;
        if (defined $path_sep) {
            my $re = qr/\Q$path_sep\E\z/;
            my $word;
            if (ref $words->[0] eq 'HASH') {
                $words = [$words->[0], {word=>"$words->[0]{word} "}] if
                    $words->[0]{word} =~ $re;
            } else {
                $words = [$words->[0], "$words->[0] "]
                    if $words->[0] =~ $re;
            }
            last;
        }

        if ($hcomp->{is_partial} ||
                ref $words->[0] eq 'HASH' && $words->[0]{is_partial}) {
            if (ref $words->[0] eq 'HASH') {
                $words = [$words->[0], {word=>"$words->[0]{word} "}];
            } else {
                $words = [$words->[0], "$words->[0] "];
            }
            last;
        }
    }

  WORKAROUND_WITH_WORDBREAKS:
    # this is a workaround. since bash breaks words using characters in
    # $COMP_WORDBREAKS, which by default is "'@><=;|&(: this presents a problem
    # we often encounter: if we want to provide with a list of strings
    # containing say ':', most often Perl modules/packages, if user types e.g.
    # "Text::AN" and we provide completion ["Text::ANSI"] then bash will change
    # the word at cursor to become "Text::Text::ANSI" since it sees the current
    # word as "AN" and not "Text::AN". the workaround is to chop /^Text::/ from
    # completion answers. btw, we actually chop /^text::/i to handle
    # case-insensitive matching, although this does not have the ability to
    # replace the current word (e.g. if we type 'text::an' then bash can only
    # replace the current word 'an' with 'ANSI).
    {
        last unless $opts->{workaround_with_wordbreaks} // 1;
        last unless defined $opts->{word};

        if ($opts->{word} =~ s/(.+[\@><=;|&\(:])//) {
            my $prefix = $1;
            for (@$words) {
                if (ref($_) eq 'HASH') {
                    $_->{word} =~ s/\A\Q$prefix\E//i;
                } else {
                    s/\A\Q$prefix\E//i;
                }
            }
        }
    }

  ESCAPE_WORDS:
    for my $entry (@$words) {
        my $word    = ref($entry) eq 'HASH' ? $entry->{word}    : $entry;
        my $summary = (ref($entry) eq 'HASH' ? $entry->{summary} : undef) // '';
        if ($esc_mode eq 'shellvar') {
            # escape $ also
            $word =~ s!([^A-Za-z0-9,+._/:~-])!\\$1!g;
        } elsif ($esc_mode eq 'none') {
            # no escaping
        } else {
            # default
            $word =~ s!([^A-Za-z0-9,+._/:\$~-])!\\$1!g;
        }
        push @words, $word;
        push @summaries, $summary;
        $has_summary = 1 if length $summary;
    }

    my $summary_align = $ENV{COMPLETE_BASH_SUMMARY_ALIGN} // 'left';
    my $max_columns = $ENV{COMPLETE_BASH_MAX_COLUMNS} // 0;
    my $terminal_width = _terminal_width();
    my $column_width = _column_width($terminal_width, $max_columns);

    #warn "terminal_width=$terminal_width, column_width=".($column_width // 'undef')."\n";

  FORMAT_SUMMARIES: {
        @res = @words;
        last if @words <= 1;
        last unless $has_summary;
        last unless $opts->{show_summaries} //
            $ENV{COMPLETE_BASH_SHOW_SUMMARIES} // 1;
        my $max_entry_width   = 8;
        my $max_summ_width = 0;
        for (0..$#words) {
            $max_entry_width = length $words[$_]
                if $max_entry_width < length $words[$_];
            $max_summ_width = length $summaries[$_]
                if $max_summ_width < length $summaries[$_];
        }
        #warn "max_entry_width=$max_entry_width, max_summ_width=$max_summ_width\n";
        if ($summary_align eq 'right') {
            # if we are aligning summary to the right, we want to fill column
            # width width
            if ($max_columns <= 0) {
                $max_columns = _num_columns(
                    $terminal_width, ($max_entry_width + 2 + $max_summ_width));
            }
            $column_width = _column_width($terminal_width, $max_columns);
            my $new_max_summ_width = $column_width - 2 - $max_entry_width;
            $max_summ_width = $new_max_summ_width
                if $max_summ_width < $new_max_summ_width;
            #warn "max_columns=$max_columns, column_width=$column_width, max_summ_width=$max_summ_width\n";
        }

        for (0..$#words) {
            my $summary = $summaries[$_];
            if (length $summary) {
                $res[$_] = sprintf(
                    "%-${max_entry_width}s |%".
                        ($summary_align eq 'right' ? $max_summ_width : '')."s",
                    $words[$_], $summary);
            }
        }
    } # FORMAT_SUMMARIES

  MAX_COLUMNS: {
        last unless $max_columns > 0;
        my $max_entry_width = 0;
        for (@res) {
            $max_entry_width = length if $max_entry_width < length;
        }
        last if $max_entry_width >= $column_width;
        for (@res) {
            $_ .= " " x ($column_width - length) if $column_width > length;
        }
    }

  PASS_TO_FZF: {
        last if $ENV{INSIDE_EMACS};
        last unless $ENV{COMPLETE_BASH_FZF};
        my $items = $ENV{COMPLETE_BASH_FZF_ITEMS} // 100;
        last unless @words >= $items;

        require File::Which;
        unless (File::Which::which("fzf")) {
            #@res = $code_return_message->("Cannot find fzf to filter ".
            #                                  scalar(@words)." items");
            goto RETURN_RES;
        }

        require IPC::Open2;
        local *CHLD_OUT;
        local *CHLD_IN;
        my $pid = IPC::Open2::open2(
            \*CHLD_OUT, \*CHLD_IN, "fzf", "-m", "-d:", "--with-nth=2..")
            or do {
                @res = $code_return_message->("Cannot open fzf to filter ".
                                                  scalar(@words)." items");
                goto RETURN_RES;
            };

        print CHLD_IN map { "$_:$res[$_]\n" } 0..$#res;
        close CHLD_IN;

        my @res_words;
        while () {
            my ($index) = /\A([0-9]+)\:/ or next;
            push @res_words, $words[$index];
        }
        if (@res_words) {
            @res = join(" ", @res_words);
        } else {
            @res = ();
        }
        waitpid($pid, 0);
    }

  RETURN_RES:
    #use Data::Dump; warn Data::Dump::dump(\@res);
    if ($as eq 'array') {
        return \@res;
    } else {
        return join("", map {($_, "\n")} @res);
    }
}

1;
# ABSTRACT: Completion routines for bash shell

__END__