132 lines
2.6 KiB
Go
132 lines
2.6 KiB
Go
package koushin
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import (
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"fmt"
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"html/template"
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"path/filepath"
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"github.com/labstack/echo/v4"
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"github.com/yuin/gopher-lua"
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"layeh.com/gopher-luar"
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)
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type Plugin interface {
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Name() string
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Filters() template.FuncMap
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Render(name string, data interface{}) error
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Close() error
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}
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type luaPlugin struct {
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filename string
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state *lua.LState
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renderCallbacks map[string]*lua.LFunction
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filters template.FuncMap
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}
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func (p *luaPlugin) Name() string {
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return p.filename
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}
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func (p *luaPlugin) onRender(l *lua.LState) int {
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name := l.CheckString(1)
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f := l.CheckFunction(2)
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p.renderCallbacks[name] = f
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return 0
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}
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func (p *luaPlugin) setFilter(l *lua.LState) int {
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name := l.CheckString(1)
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f := l.CheckFunction(2)
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p.filters[name] = func(args... interface{}) string {
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luaArgs := make([]lua.LValue, len(args))
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for i, v := range args {
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luaArgs[i] = luar.New(l, v)
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}
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err := l.CallByParam(lua.P{
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Fn: f,
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NRet: 1,
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Protect: true,
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}, luaArgs...)
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if err != nil {
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panic(err) // TODO: better error handling?
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}
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ret := l.CheckString(-1)
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l.Pop(1)
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return ret
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}
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return 0
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}
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func (p *luaPlugin) Render(name string, data interface{}) error {
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f, ok := p.renderCallbacks[name]
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if !ok {
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return nil
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}
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err := p.state.CallByParam(lua.P{
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Fn: f,
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NRet: 0,
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Protect: true,
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}, luar.New(p.state, data))
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if err != nil {
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return err
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}
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return nil
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}
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func (p *luaPlugin) Filters() template.FuncMap {
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return p.filters
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}
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func (p *luaPlugin) Close() error {
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p.state.Close()
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return nil
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}
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func loadLuaPlugin(filename string) (*luaPlugin, error) {
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l := lua.NewState()
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p := &luaPlugin{
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filename: filename,
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state: l,
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renderCallbacks: make(map[string]*lua.LFunction),
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filters: make(template.FuncMap),
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}
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mt := l.NewTypeMetatable("koushin")
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l.SetGlobal("koushin", mt)
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l.SetField(mt, "on_render", l.NewFunction(p.onRender))
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l.SetField(mt, "set_filter", l.NewFunction(p.setFilter))
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if err := l.DoFile(filename); err != nil {
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l.Close()
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return nil, err
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}
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return p, nil
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}
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func loadAllLuaPlugins(log echo.Logger) ([]Plugin, error) {
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filenames, err := filepath.Glob("plugins/*.lua")
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if err != nil {
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return nil, fmt.Errorf("filepath.Glob failed: %v", err)
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}
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plugins := make([]Plugin, 0, len(filenames))
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for _, filename := range filenames {
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log.Printf("Loading Lua plugin '%v'", filename)
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p, err := loadLuaPlugin(filename)
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if err != nil {
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for _, p := range plugins {
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p.Close()
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}
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return nil, fmt.Errorf("failed to load Lua plugin '%v': %v", filename, err)
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}
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plugins = append(plugins, p)
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}
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return plugins, nil
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}
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