scripts/hxtool-conv: Archive script used in qemu-options.hx conversion

This commit archives the perl script used to do conversion of the
STEXI/ETEXI blocks in qemu-options.hx. (The other .hx files were
manually converted, but qemu-options.hx is complicated enough that
I felt I needed some scripting.)

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Reviewed-by: Alex Bennée <alex.bennee@linaro.org>
Tested-by: Alex Bennée <alex.bennee@linaro.org>
Message-id: 20200228153619.9906-26-peter.maydell@linaro.org

scripts/hxtool-conv.pl

+#!/usr/bin/perl -w
+#
+# Script to convert .hx file STEXI/ETEXI blocks to SRST/ERST
+#
+# Copyright (C) 2020 Linaro
+#
+# This work is licensed under the terms of the GNU GPL, version 2 or
+# (at your option) any later version. See the COPYING file in the
+# top-level directory.
+
+# This script was only ever intended as a one-off conversion operation.
+# Please excuse the places where it is a bit hacky.
+# Some manual intervention after the conversion is expected, as are
+# some warnings from makeinfo.
+# Warning: this script is not idempotent: don't try to run it on
+# a .hx file that already has SRST/ERST sections.
+
+# Expected usage:
+# scripts/hxtool-conv.pl file.hx > file.hx.new
+
+use utf8;
+
+my $reading_texi = 0;
+my $texiblock = '';
+my @tables = ();
+
+sub update_tables($) {
+    my ($texi) = @_;
+    # Update our list of open table directives: every @table
+    # line in the texi fragment is added to the list, and every
+    # @end table line means we remove an entry from the list.
+    # If this fragment had a completely self contained table with
+    # both the @table and @end table lines, this will be a no-op.
+    foreach (split(/\n/, $texi)) {
+        push @tables, $_ if /^\@table/;
+        pop @tables if /^\@end table/;
+    }
+}
+
+sub only_table_directives($) {
+    # Return true if every line in the fragment is a start or end table directive
+    my ($texi) = @_;
+    foreach (split(/\n/, $texi)) {
+        return 0 unless /^\@table/ or /^\@end table/;
+    }
+    return 1;
+}
+
+sub output_rstblock($) {
+    # Write the output to /tmp/frag.texi, wrapped in whatever current @table
+    # lines we need.
+    my ($texi) = @_;
+
+    # As a special case, if this fragment is only table directives and
+    # nothing else, update our set of open table directives but otherwise
+    # ignore it. This avoids emitting an empty SRST/ERST block.
+    if (only_table_directives($texi)) {
+        update_tables($texi);
+        return;
+    }
+
+    open(my $fragfh, '>', '/tmp/frag.texi');
+    # First output the currently active set of open table directives
+    print $fragfh join("\n", @tables);
+    # Next, update our list of open table directives.
+    # We need to do this before we emit the closing table directives
+    # so that we emit the right number if this fragment had an
+    # unbalanced set of directives.
+    update_tables($texi);
+    # Then emit the texi fragment itself.
+    print $fragfh "\n$texi\n";
+    # Finally, add the necessary closing table directives.
+    print $fragfh "\@end table\n" x scalar @tables;
+    close $fragfh;
+
+    # Now invoke makeinfo/pandoc on it and slurp the results into a string
+    open(my $fh, '-|', "makeinfo --force -o - --docbook "
+         . "-D 'qemu_system_x86 QEMU_SYSTEM_X86_MACRO' "
+         . "-D 'qemu_system     QEMU_SYSTEM_MACRO'  /tmp/frag.texi "
+         . " | pandoc  -f docbook -t rst")
+        or die "can't start makeinfo/pandoc: $!";
+
+    binmode $fh, ':encoding(utf8)';
+
+    print "SRST\n";
+
+    # Slurp the whole thing into a string so we can do multiline
+    # string matches on it.
+    my $rst = do {
+        local $/ = undef;
+        <$fh>;
+    };
+    $rst =~ s/^-  − /-  /gm;
+    $rst =~ s/“/"/gm;
+    $rst =~ s/”/"/gm;
+    $rst =~ s/‘/'/gm;
+    $rst =~ s/’/'/gm;
+    $rst =~ s/QEMU_SYSTEM_MACRO/|qemu_system|/g;
+    $rst =~ s/QEMU_SYSTEM_X86_MACRO/|qemu_system_x86|/g;
+    $rst =~ s/(?=::\n\n +\|qemu)/.. parsed-literal/g;
+    $rst =~ s/:\n\n::$/::/gm;
+
+    # Fix up the invalid reference format makeinfo/pandoc emit:
+    # `Some string here <#anchorname>`__
+    # should be:
+    # :ref:`anchorname`
+    $rst =~ s/\`[^<`]+\<\#([^>]+)\>\`__/:ref:`$1`/gm;
+    print $rst;
+
+    close $fh or die "error on close: $!";
+    print "ERST\n";
+}
+
+# Read the whole .hx input file.
+while (<>) {
+    # Always print the current line
+    print;
+    if (/STEXI/) {
+        $reading_texi = 1;
+        $texiblock = '';
+        next;
+    }
+    if (/ETEXI/) {
+        $reading_texi = 0;
+        # dump RST version of block
+        output_rstblock($texiblock);
+        next;
+    }
+    if ($reading_texi) {
+        # Accumulate the texi into a string
+        # but drop findex entries as they will confuse makeinfo
+        next if /^\@findex/;
+        $texiblock .= $_;
+    }
+}
+
+die "Unexpectedly still in texi block at EOF" if $reading_texi;