zproject_lua_ffi.gsl

#   Generate minimal Lua language bindings that use CFFI.
#
#   These are not meant to be idiomatic, but to provide a minimal platform
#   of FFI function bindings on which to base idiomatic Lua code.
#
#   This is a code generator built using the iMatix GSL code generation
#   language. See https://github.com/imatix/gsl for details.
#
#   Copyright (c) the Contributors as noted in the AUTHORS file.
#   This file is part of zproject.
#
#   This Source Code Form is subject to the terms of the Mozilla Public
#   License, v. 2.0. If a copy of the MPL was not distributed with this
#   file, You can obtain one at http://mozilla.org/MPL/2.0/.

register_target ("lua_ffi", "Lua FFI binding")

#   Target provides name space isolation for its functions
function target_lua_ffi

function register_type (struct, pointer)
    if count(project->lua_types.type, type.name = my.struct) = 0
        new project->lua_types.type
            type.name = my.struct
            type.pointer = my.pointer
        endnew
    endif
endfunction

function resolve_container (container)
    if my.container.variadic
    elsif my.container.type = "nothing"
    elsif my.container.type = "anything" | my.container.type = "sockish"
    elsif my.container.type = "boolean"
    elsif my.container.type = "byte"
    elsif my.container.type = "integer" | my.container.type = "file_size" | my.container.type = "time"
    elsif my.container.type = "number"
    elsif my.container.type = "size"
    elsif my.container.type = "real"
    elsif my.container.type = "buffer"
    elsif my.container.type = "FILE"
    elsif my.container.type = "string" | my.container.type = "format"
    elsif my.container.callback
    else
        register_type ("$(my.container.type:c,no)_t", "$(my.container.type:c,no)_p")
    endif
endfunction

function resolve_method (method)
    my.method.python_name = "$(my.method.name:c)"
    if regexp.match ("^(is|from)$", my.method.python_name) # matches keyword
        my.method.python_name += "_"
    endif
    for my.method.argument where !argument.variadic
        resolve_container (argument)
    endfor
    for my.method.return as ret
        resolve_container (ret)
    endfor
endfunction

function resolve_class (class)
    register_type("$(class.c_name)_t", "$(class.c_name)_p")
    for my.class.callback_type as method
        resolve_method (method)
    endfor
    for my.class.constructor as method
        resolve_method (method)
    endfor
    for my.class.destructor as method
        resolve_method (method)
    endfor
    for my.class.method
        resolve_method (method)
    endfor
endfunction

function generate_binding
    directory.create ("bindings/lua_ffi")
    output "bindings/lua_ffi/$(project.name:c)_ffi.lua"
    >$(project.GENERATED_WARNING_HEADER_FOR_LUA:)
    >
    >$(project.name:c)_ffi = {}
    >$(project.name:c)_ffi.ffi = require ("ffi")
    >
    >-- typedefs simulating C standard library
    >-- see https://github.com/eliben/pycparser/blob/master/utils/fake_libc_include/_fake_defines.h
    >$(project.name:c)_ffi.ffi.cdef [[
    >typedef struct __FILE FILE;
    >typedef int time_t;
    >typedef int off_t;
    >]]
    >
    >-- czmq_prelude.h
    >$(project.name:c)_ffi.ffi.cdef [[
    >typedef unsigned char byte;
    >typedef int SOCKET;
    >]]
    >$(project.name:c)_ffi.ffi.cdef [[
    for project->lua_types.type as t
        >typedef struct _$(t.name:c) $(t.name:c);
    endfor
    for class where defined (class.api) & class.private = "0"
        for class.callback_type
            >// $(callback_type.description:no,block)
            >$(c_callback_typedef (callback_type):)
            >
        endfor
    endfor
    for class where defined (class.api) & class.private = "0"
        >// CLASS: $(class.name)
        for class. as f
            if class(f) = "XML item" & (name(f) = 'constructor' | name(f) = 'destructor')
                >// $(f.description:no,block)
                >$(c_method_signature (f):);
                >
            endif
        endfor
        for class.actor
            >// $(actor.description:no,block)
            >$(PROJECT.PREFIX)_EXPORT void
            >   $(actor.name:c) (zsock_t *pipe, void *args);
            >
        endfor
        for class.method
            >// $(method.description:no,block)
            >$(c_method_signature (method):);
            >
        endfor
    endfor
    >]]
    >
    >$(project.name:c)_ffi.$(prefix) = $(project.name:c)_ffi.ffi.load ("$(project.libname)")
    >return $(project.name:c)_ffi
endfunction

    if count (class, defined (class.api) & class.private = "0")
        # Container for UDTs used by this module
        new lua_types
        endnew
        for class where defined (class.api) & class.private = "0"
            resolve_class (class)
        endfor
        generate_binding ()
    endif
endfunction