Implement a shared library loader with go1.8(experimental)

config.go

@@ -20,15 +20,21 @@ var LuaPath = "LUA_PATH"
 var LuaLDir string
 var LuaPathDefault string
 var LuaOS string
+var LuaCDir string
+var LuaCPathDefault string
 
 func init() {
 	if os.PathSeparator == '/' { // unix-like
 		LuaOS = "unix"
 		LuaLDir = "/usr/local/share/lua/5.1"
 		LuaPathDefault = "./?.lua;" + LuaLDir + "/?.lua;" + LuaLDir + "/?/init.lua"
+		LuaCDir = "/usr/local/lib/glua/5.1"
+		LuaCPathDefault = "./?.so;" + LuaCDir + "/?.so;" + LuaCDir + "/loadall.so;"
 	} else { // windows
 		LuaOS = "windows"
 		LuaLDir = "!\\lua"
 		LuaPathDefault = ".\\?.lua;" + LuaLDir + "\\?.lua;" + LuaLDir + "\\?\\init.lua"
+		LuaCDir = "!\\"
+		LuaPathDefault = ".\\?.dll;" + LuaCDir + "\\?.dll;" + LuaCDir + "\\?\\loadall.dll"
 	}
 }

loadlib.go

@@ -4,12 +4,16 @@ import (
 	"fmt"
 	"os"
 	"path/filepath"
+	"plugin"
+	"regexp"
 	"strings"
 )
 
 /* load lib {{{ */
 
-var loLoaders = []LGFunction{loLoaderPreload, loLoaderLua}
+const loRegPrefix = "LOADLIB: "
+
+var loLoaders = []LGFunction{loLoaderPreload, loLoaderLua, loLoaderC}
 
 func loGetPath(env string, defpath string) string {
 	path := os.Getenv(env)
@@ -46,6 +50,58 @@ func loFindFile(L *LState, name, pname string) (string, string) {
 	return "", strings.Join(messages, "\n\t")
 }
 
+func loRegister(L *LState, path string) *LUserData {
+	rname := loRegPrefix + path
+	reg := L.Get(RegistryIndex).(*LTable)
+	r := reg.RawGetString(rname)
+	if r != LNil {
+		return r.(*LUserData)
+	}
+	plib := L.NewUserData()
+	plib.Value = nil
+	L.SetMetatable(plib, L.GetMetatable(reg))
+	reg.RawSetString(rname, plib)
+	return plib
+}
+
+func loSym(L *LState, ud *LUserData, sym string) (*LFunction, error) {
+	p := ud.Value.(*plugin.Plugin)
+	f, err := p.Lookup(sym)
+	if err != nil {
+		return nil, err
+	}
+	return L.NewFunction(f.(func(*LState) int)), nil
+}
+
+func loLoadFunc(L *LState, path, sym string) (*LFunction, error) {
+	ud := loRegister(L, path)
+	if ud.Value == nil {
+		p, err := plugin.Open(path)
+		if err != nil {
+			return nil, err
+		}
+		ud.Value = p
+	}
+
+	f, err := loSym(L, ud, sym)
+	if err != nil {
+		return nil, err
+	}
+	return f, nil
+}
+
+func loMakeFuncName(s string) string {
+	re := regexp.MustCompile("^[^\\-]*\\-")
+	name := re.ReplaceAllString(s, "")
+
+	re = regexp.MustCompile("\\.(\\w)")
+
+	funcname := re.ReplaceAllStringFunc(name, func(s string) string {
+		return strings.ToUpper(re.FindStringSubmatch(s)[1])
+	})
+	return "LuaOpen" + strings.Title(funcname)
+}
+
 func OpenPackage(L *LState) int {
 	packagemod := L.RegisterModule(LoadLibName, loFuncs)
 
@@ -104,9 +160,37 @@ func loLoaderLua(L *LState) int {
 	return 1
 }
 
+func loLoaderC(L *LState) int {
+	name := L.CheckString(1)
+	path, msg := loFindFile(L, name, "cpath")
+	if len(path) == 0 {
+		L.Push(LString(msg))
+		return 1
+	}
+	f, err := loLoadFunc(L, path, loMakeFuncName(name))
+	if err != nil {
+		L.RaiseError(err.Error())
+	}
+	L.Push(f)
+	return 1
+}
+
 func loLoadLib(L *LState) int {
-	L.RaiseError("loadlib is not supported")
-	return 0
+	path := L.CheckString(1)
+	init := L.CheckString(2)
+	f, err := loLoadFunc(L, path, init)
+	if err != nil {
+		L.Push(LNil)
+		L.Push(LString(err.Error()))
+		if strings.Contains(err.Error(), "plugin.Open") {
+			L.Push(LString("open"))
+		} else {
+			L.Push(LString("init"))
+		}
+		return 3
+	}
+	L.Push(f)
+	return 1
 }
 
 func loSeeAll(L *LState) int {