c 集成 lua 模块的方法

A_luafiles_in_c

includes("./luafiles.lua")

--[[
对于这个target就不需要调用 <module_name>_loadmodules 函数了
见 test.c 中的例子
]]
target("lua_require")
  set_kind("static")
	add_files("require.lua")
	add_rules("luafiles", {root_path = ".", module_name = "require"})

-- 为每一个 lua 提供一个 target 目标
target("Penlight")
  set_kind("static")
	add_files("Penlight/lua/pl/**.lua")
	add_rules("luafiles", {root_path = "Penlight/lua", module_name = "pl"})
  
  
--[[

]]
  
target("Program")
  add_deps("lua_require", Penlight)

luafiles.lua

--[[
利用 objcopy 将 root_path 下的所有 lua 文件变成符号
需要配合特殊的 require 去识别这些内容。

该规则会生成一个 c 文件
暴露一个符号: <module_name>_loadmodules,需要在 c 中调用。
不需要 include 文件。 直接 extern void <module_name>_loadmodules( lua_State * state );
该函数会向栈顶的 table 注册注册一个名为 <module_name> 的 table
该 table 将按照 路径:文件内容 的模式存数存储所有的lua 文件内容。
该路径是 lua 文件相对于 root_path 的路径。
并且将分割替换为 '.', 去除文件后缀。

利用 debug 模块提供的调用源的 source 字段，实现相对路径的识别。
这会临时修改 package.path 印象 lua 的文件查找逻辑

]]
rule("luafiles")
    set_extensions(".lua")

    on_load(function(target)
        local root_path = target:extraconf("rules", "luafiles", "root_path")
        local module_name = target:extraconf("rules", "luafiles", "module_name") or target:name()
        assert(root_path)

        local chunks = "";
        local changed = false

        for _, sourcefile in ipairs(target:sourcebatches().luafiles.sourcefiles) do
            local filepath = sourcefile
            local objectfile = target:objectfile(sourcefile)

            local f_mtime = os.mtime(filepath);
            local o_mtime = os.mtime(objectfile);

            local projectdir = vformat("$(projectdir)")
            local r_filepath = path.relative(projectdir .. "/" .. sourcefile, target:scriptdir() .. "/"  .. root_path)

            local binary_name = r_filepath:gsub("[\\/.-]", "_")
            local chunk_name = r_filepath:gsub("[\\/]", "."):sub(1, -1 - 4)
            chunks = chunks .. format([[
                    {
                    #define XXX(X) \
                        extern const char ]] .. module_name .. [[_binary_##X##_start; \
                        extern const char ]] .. module_name .. [[_binary_##X##_end; \
                        const char* _start = &]] .. module_name .. [[_binary_##X##_start; \
                        const char* _end   = &]] .. module_name .. [[_binary_##X##_end; \
                        size_t      _size  = _end - _start;
                    XXX(%s)

                    lua_pushstring(L, "%s" );
                    luaL_loadbuffer(L, _start, _size, "@M@%s");
                    lua_settable(L, -3);

                    #undef XXX
                    }
                ]], binary_name, chunk_name, chunk_name)

            if f_mtime > o_mtime then
                changed = true
            end
        end

        local module_c_filepath = target:autogendir() .. "/" .. module_name .. ".c"
        if changed or not os.isfile(module_c_filepath) then
            io.writefile(module_c_filepath, [[
                    #include <lualib.h>
                    #include <lauxlib.h>
                    #include <string.h>

                    void ]] .. module_name .. [[_loadmodules(lua_State* L) {

                        lua_pushstring(L, "]] .. module_name .. [[");
                        lua_newtable(L);

                        ]] .. chunks .. [[

                        lua_settable( L, -3 );
                    }
                ]]);
        end

        target:add("files", module_c_filepath)
    end)

    before_build(function(target)
        import("lib.detect.find_program")

        local root_path = target:extraconf("rules", "luafiles", "root_path")
        local module_name = target:extraconf("rules", "luafiles", "module_name") or target:name()
        assert(root_path)

        local projectdir = vformat("$(projectdir)/")
        local scriptdir = vformat("$(scriptdir)/")
        local sourcedir = target:scriptdir() .. "/" .. root_path

        local changed = false;
        local lua_files = {};

        local luac = find_program("luac")

        for _, sourcefile in ipairs(target:sourcebatches().luafiles.sourcefiles) do

            local objectfile = path.relative(target:objectfile(sourcefile), projectdir)

            sourcefile = projectdir .. sourcefile

            local r_filepath = path.relative(sourcefile, sourcedir)
            local a_filepath = projectdir .. objectfile

            local f_mtime = os.mtime(sourcefile);
            local a_mtime = os.mtime(a_filepath);

            table.insert(lua_files, a_filepath)

            if f_mtime > a_mtime then
                changed = true;

                os.cd(sourcedir)
                os.mkdir(path.directory(a_filepath))

                os.execv("objcopy",
                    {"-I", "binary", "-O", "elf64-x86-64", "--prefix-symbols", module_name, r_filepath, a_filepath})

                os.execv("objcopy",
                    {"-I", "binary", "-O", "elf64-x86-64", "--prefix-symbols", module_name, r_filepath, a_filepath})

                os.cd("-")
            end
        end

        local out_filepath = projectdir .. path.relative(target:autogendir() .. "/" .. module_name .. ".obj", projectdir)

        -- 合并 obj
        if changed then
            os.mkdir(path.directory(out_filepath))
            os.runv(target:tool("ld"), table.join2({"-r", "-o", out_filepath}, lua_files))
        end

        table.insert(target:objectfiles(), out_filepath)
    end)

request.lua

local realRequire = require;
local __internal_packages = {}

local function string_split(path, sep)
    local stack = {};

    local _last_end = 1
    local _s = 1 -- 游标
    while _s do
        _s = path:find(sep, _s)
        if _s then
            table.insert(stack, path:sub(_last_end, _s - 1))
            _s = _s + 1
            _last_end = _s
        else
            table.insert(stack, path:sub(_last_end))
            break
        end
    end

    return stack
end

local function string_find_last(string, substring, count)
    count = count or 1
    local list = {};
    table.insert(list, 0)

    local _s = 1
    while _s do
        _s = string:find(substring, _s)
        if _s then
            table.insert(list, _s)
            _s = _s + 1
        else
            break
        end
    end

    return list[#list - (count - 1)]
end

-- 针对文件
local function get_source_dir(up)
    if up:sub(1, 1) ~= '@' then
        return realRequire(name);
    end
    up = up:sub(2)

    local sep_index = string_find_last(up, "/");
    if sep_index ~= 0 then
        return up:sub(1, sep_index)
    end

    return
end

local function get_module(name)
    local module = package.loaded[name]
    if module then
        return module
    end

    for package_name, modules in pairs(__internal_packages) do
        local module = modules[name] or modules[name .. ".init"];
        if module then
            module = module()
            package.loaded[name] = module;
            return module or true
        end
    end
end

-- root: a.b.c.d.e
-- path: ./
-- path: ../././../
-- path 确保是 ./ 开头
local function fix_relative_paths(root, path)
    path = path:gsub("[\\]", "/"):gsub("\\\\", "")

    local root_path_stack = string_split(root, "[.]")
    local path_stack = string_split(path, "/")

    table.remove(root_path_stack, #root_path_stack)

    local remove_count = 0
    for _, v in ipairs(path_stack) do
        if v == "." then
        elseif v == ".." then
            if #root_path_stack == 0 then
                break
            end
            table.remove(root_path_stack, #root_path_stack)
        else
            break
        end

        remove_count = remove_count + 1
    end

    if (#path_stack - remove_count) ~= 1 then
        return nil
    end

    for i = 1, remove_count do
        table.remove(path_stack, 1)
    end

    local parent_path = table.concat(root_path_stack, ".");
    local child_path = table.concat(path_stack, ".");

    -- 如果找到 . 则去掉 .*
    if #parent_path > 0 then
        return parent_path .. "." .. child_path
    end

    return child_path
end

local function relative_require(name)

    if name:sub(1, 1) == '.' then
        local _name = name:gsub("\\", "/");
        local rela_path = _name:match("^[./]+")
        local short_name = _name:sub(#rela_path + 1)

        local up = debug.getinfo(2, "S").source:gsub("\\", "/");
        if up:sub(1, 3) == "@M@" then -- 内部模块
            local up_module_path = up:sub(4)
            module_name = fix_relative_paths(up_module_path, name)
            local module = get_module(module_name)
            if (module) then
                return module
            else
                error("Couldn't find module: " .. name)
            end
        elseif up:sub(1, 1) == "@" then -- 文件路径
            local source_dir = get_source_dir(up)

            local old_ppath = package.path;
            if source_dir then
                local pdir = (source_dir .. "/" .. rela_path .. "/"):gsub("//", "/")

                package.path = pdir .. "?.lua;" .. pdir .. "?/init.lua;" .. package.path
            end
            local ret = realRequire(short_name)
            package.path = old_ppath;
            return ret;
        else --
            return;
        end
    else
        return get_module(name) or realRequire(name)
    end
end

function require(name)
    if not name or #name == 0 then
        return realRequire(name)
    end

    return relative_require(name)
end

return __internal_packages

test.c

int set(){
  int require_ret = LUA_OK;
	do {
		extern const char require_binary_require_lua_start;
		extern const char require_binary_require_lua_end;
		size_t require_binary_require_lua_size = &require_binary_require_lua_end - &require_binary_require_lua_start;

		require_ret = luaL_loadbuffer(
		  L, &require_binary_require_lua_start, require_binary_require_lua_size, "_binary_require_lua" );
		if ( require_ret != LUA_OK )
			break;
		require_ret = lua_pcall( L, 0, 1, 0 ); // return local:__internal_packages
		if ( require_ret != LUA_OK )
			break;

		extern void pl_loadmodules( lua_State * state );
		pl_loadmodules( L );

		lua_pop( L, 1 ); // pop table:__internal_packages
	} while ( 0 );
	assert( require_ret == LUA_OK );
}