a perl6 script to call libmaxminddb using NativeCall

maxminddb.p6

#!/usr/bin/env perl6-m
use v6;
use NativeCall;
class MaxMindDB {

    enum MMDB_DATA_TYPE (
        MMDB_DATA_TYPE_EXTENDED => 0,
        MMDB_DATA_TYPE_POINTER => 1,
        MMDB_DATA_TYPE_UTF8_STRING => 2,
        MMDB_DATA_TYPE_DOUBLE => 3,
        MMDB_DATA_TYPE_BYTES => 4,
        MMDB_DATA_TYPE_UINT16 => 5,
        MMDB_DATA_TYPE_UINT32 => 6,
        MMDB_DATA_TYPE_MAP => 7,
        MMDB_DATA_TYPE_INT32 => 8,
        MMDB_DATA_TYPE_UINT64 => 9,
        MMDB_DATA_TYPE_UINT128 => 10,
        MMDB_DATA_TYPE_ARRAY => 11,
        MMDB_DATA_TYPE_CONTAINER => 12,
        MMDB_DATA_TYPE_END_MARKER => 13,
        MMDB_DATA_TYPE_BOOLEAN => 14,
        MMDB_DATA_TYPE_FLOAT => 15,
    );

    enum MMDB (
        MMDB_SUCCESS => 0,
        MMDB_FILE_OPEN_ERROR => 1,
        MMDB_CORRUPT_SEARCH_TREE_ERROR => 2,
        MMDB_INVALID_METADATA_ERROR => 3,
        MMDB_IO_ERROR => 4,
        MMDB_OUT_OF_MEMORY_ERROR => 5,
        MMDB_UNKNOWN_DATABASE_FORMAT_ERROR => 6,
        MMDB_INVALID_DATA_ERROR => 7,
        MMDB_INVALID_LOOKUP_PATH_ERROR => 8,
        MMDB_LOOKUP_PATH_DOES_NOT_MATCH_DATA_ERROR => 9,
        MMDB_INVALID_NODE_NUMBER_ERROR => 10,
        MMDB_IPV6_LOOKUP_IN_IPV4_DATABASE_ERROR => 11,
    );

    class MMDB_entry_data_s is repr('CStruct') {
        # CStruct don't support bool
        has int $.has_data;
        has int32 $.pointer;
        has Str $.utf8_string;
        has num $.double_value;
        has int8 $.bytes;
        has int16 $.uint16;
        has int32 $.uint32;
        has int32 $.int32;
        has int64 $.uint64;
        has CArray[int8] $.uint128;
        # CStruct don't support bool
        has int $.boolean;
        has num32 $.float_value;
        has int32 $.offset;
        has int32 $.offset_to_next;
        has int32 $.data_size;
        has int32 $.type;
    }
    class MMDB_ipv4_start_node_s is repr('CStruct') {
        has int16 $.netmask;
        has int32 $.node_value;
    }
    class MMDB_description_s is repr('CStruct') {
        has Str $.language;
        has Str $.description;
    }
    class metadata_languages is repr('CStruct') {
        has int $.count;
        has Str $.names;
    }
    class metadata_description is repr('CStruct') {
        has int $.count;
        has MMDB_description_s $.descriptions;
    }
    class MMDB_metadata_s is repr('CStruct') {
        has int32 $.node_count;
        has int16 $.record_size;
        has int16 $.ip_version;
        has Str $.database_type;
        has metadata_languages $.languages;
        has int16 $.binary_format_major_version;
        has int16 $.binary_format_minor_version;
        has int64 $.build_epoch;
        has metadata_description $.description;
    }
    class MMDB_entry_data_list_s is repr('CStruct') {
        has MMDB_entry_data_s $.entry_data;
        has MMDB_entry_data_list_s $.next;
    }
    class MMDB_s is repr('CStruct') {
        has int32 $.flags;
        has Str $.filename;
        has int $.file_size;
        has int8 $.file_content;
        has int8 $.data_section;
        has int32 $.data_section_size;
        has int8 $.metadata_section;
        has int32 $.metadata_section_size;
        has int16 $.full_record_byte_size;
        has int16 $.depth;
        has MMDB_ipv4_start_node_s $.ipv4_start_node;
        has MMDB_metadata_s $.metadata;
    }
    class MMDB_entry_s is repr('CStruct') {
        has MMDB_s $.mmdb;
        has int32 $.offset;
    }
    class MMDB_lookup_result_s is repr('CStruct') {
        # CStruct don't support bool
        has int $.found_entry;
        has MMDB_entry_s $.entry;
        has int16 $.netmask;
    }

    sub LIB  {
        given $*VM.config{'load_ext'} {
            when '.so'      { return 'libmaxminddb.so.1' }   # Linux
            when '.bundle'  { return 'libmaxminddb.dylib' }  # Mac OS
            default         { return 'libmaxminddb' }
        }
    }

    sub MMDB_open ( Str, Int, MMDB_s ) returns Int is native( LIB ) { * }
    sub MMDB_lookup_string ( MMDB_s, Str, Int, Int ) returns MMDB_lookup_result_s is native( LIB ) { * }
    sub MMDB_aget_value ( MMDB_entry_s, MMDB_entry_data_s, CArray[Str] ) returns Int is native( LIB ) { * }
    sub MMDB_get_entry_data_list ( MMDB_entry_s, MMDB_entry_data_list_s ) returns Int is native( LIB ) { * }
    sub MMDB_free_entry_data_list ( MMDB_entry_data_list_s ) returns Bool is native( LIB ) { * }
    sub MMDB_close ( MMDB_s ) returns Bool is native( LIB ) { * }
    sub MMDB_lib_version ( Bool ) returns Str is native( LIB ) { * }
    sub MMDB_strerror ( Int ) returns Str is native( LIB ) { * }

    sub MMDB_entry_to_perl ( MMDB_entry_data_list_s $entry_data_list ) {
        my $first = $entry_data_list;

        while $entry_data_list.next -> $entry_data_list {

            given $entry_data_list.entry_data.type {
                when MMDB_DATA_TYPE_MAP { ... }
                when MMDB_DATA_TYPE_ARRAY { ... }
                when MMDB_DATA_TYPE_UTF8_STRING {
                    say $entry_data_list.entry_data.utf8_string;
                    last;
                }
            }

        }
        MMDB_free_entry_data_list($first);
    }

    has MMDB_s $!mmdb = .new;
    has Str $!file where $_.IO ~~ :f & :r;
    submethod BUILD ( :$!file ) {
        # MMDB_MODE_MMAP == 1
        my $ret = MMDB_open($!file, 1, $!mmdb);
        if MMDB_SUCCESS != $ret {
            note MMDB_strerror($ret);
            exit(2);
        }
    }
    submethod DESTROY {
        MMDB_close($!mmdb);
    }
    method lookup ( Str $ip where /^\d+\.\d+\.\d+\.\d+$/ ) {
        my ($gai_error, $mmdb_error);
        my $result = MMDB_lookup_string( $!mmdb, $ip, $gai_error, $mmdb_error);

        if $gai_error {
            note "Error from call to getaddrinfo for {$ip}";
            exit(3);
        }
        if MMDB_SUCCESS != $mmdb_error {
            my $err_msg = MMDB_strerror($mmdb_error);
            note "Got an error from the maxminddb library: {$err_msg}";
            exit(4);
        }

        return $result;
    }

    multi method get ( Str $ip! where /^\d+\.\d+\.\d+\.\d+$/, @path = [] ) {
        my $result = $.lookup($ip);
        my MMDB_entry_data_list_s $entry_data_list = .new;
        my @c_path := CArray[Str].new();
        @c_path[$_] = @path[$_] for ^@path.elems;
        @c_path[@path.elems] = Str;
        if $result.found_entry {
            my Int $status;
            my MMDB_entry_data_s $entry_data = .new;
            $status = MMDB_aget_value( $result.entry, $entry_data, @c_path);
            if MMDB_SUCCESS == $status {
                if $entry_data.offset {
                    my $entry = MMDB_entry_s.new(mmdb => $!mmdb, offset => $entry_data.offset);
                    $status = MMDB_get_entry_data_list($entry, $entry_data_list);

                }
            }
            if MMDB_SUCCESS != $status {
                note "Got an error looking up the entry data - {MMDB_strerror($status)}";
            }
            MMDB_entry_to_perl($entry_data_list);
        }
        MMDB_free_entry_data_list($entry_data_list);
    }

}

my $mmdb = MaxMindDB.new(file=>'/Users/raochenlin/gitdir/rsyslog-maxminddb/src/tests/test.mmdb');
$mmdb.get("202.106.0.20",["city"]);
# set filetype=perl6

Not totally complete. Because NativeCall don't support __int128 and bool in CStruct now.
the submethod BUILD got segmentfault at MMDB_open call, I believe this must because the structs...