Doxygen filter for Google Protocol Buffers (protobuf, GPB)

doxy-filter-proto.pl

#!/usr/bin/env perl

##############################################################################
#
# Copyright 2021, NDP LLC
#
# Redistribution and use in source and binary forms, with or without
# modification, are permitted provided that the following conditions are met:
#
# 1. Redistributions of source code must retain the above copyright notice,
# this list of conditions and the following disclaimer.
#
# 2. Redistributions in binary form must reproduce the above copyright notice,
# this list of conditions and the following disclaimer in the documentation
# and/or other materials provided with the distribution.
#
# THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
# AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
# IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
# ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE
# LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
# CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
# SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
# INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
# CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
# ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
# POSSIBILITY OF SUCH DAMAGE.
#
##############################################################################

use strict;
use warnings;

sub format_field {
  my ($t, $f, $n, $opts) = $_ =~ m,(optional|required|repeated)\s+(.*?)\s*=\s*(\d+)\s*(?:\[(.*?)\])?\s*;,;
  #$f =~ s/\b([us]?int\d+)/${1}_t/;
  #$f =~ s/\b(string)/std::${1}/;
  my @a = ("index($n)");
  my $d = "";
  if ($t eq "repeated") {
    $f .= "[]";
    $d = " = {}";
  }
  if ($t eq "repeated") {
    push @a, $t;
  }
  if ($t eq "required") {
    push @a, $t;
  }
  if ($opts) {
    foreach $_ (split(/\s*,\s*/, $opts)) {
      s/^\s+|\s+$//g;
      if (s/^default\s*=\s*//) {
        $d = " = $_";
      } else {
        s/\s*=\s*(.*)/($1)/;
        s/\s*\(true\s*\)//;
        push @a, $_;
      }
    }
  }
  $a = join(" ", @a);
  "$f$d [$a];"
}

my @ns = ();
my $enum = 0;
while (<>) {
  chomp;
  my ($space, $line, $comment) = m!^(\s*)(.*?)(\s*//.*)?$!g;
  my ($word) = $line =~ m/^\s*(\w+)/g;
  $comment = "" unless $comment;
  $word = "" unless $word;
  if ($word eq "option" || $word eq "syntax") {
    $line = "// $line";
  } elsif ($word eq "import") {
    $line =~ s/import/#include/;
    $line =~ s/;\s*$//;
  } elsif ($word eq "package") {
    my ($package) = $line =~ m/^\s*package\s+([^\s;]*).*$/g;
    @ns = split(/\./, $package);
    $line = join(" ", map { "namespace $_ {" } @ns);
  } elsif ($word eq "message") {
    $line =~ s/message/struct/;
  } elsif ($word eq "enum") {
    $enum = 1;
  } elsif ($word eq "optional" || $word eq "required" || $word eq "repeated") {
    $line = format_field($line);
  }
  if ($enum) {
    $line =~ s/;/,/g;
    $enum = 0 if $line =~ m/}/;
  }
  $line =~ s/}\s*$/};/g;
  print "$space$line$comment\n";
}
if (@ns) {
  print(("}") x @ns, "\n");
}