gosora/common/pluginlangs.go

package common

import (
    "encoding/json"
    "errors"
    "io/ioutil"
    "path/filepath"
)

var pluginLangs = make(map[string]PluginLang)

// For non-native plugins to bind JSON files to. E.g. JS and Lua
type PluginMeta struct {
    UName    string
    Name     string
    Author   string
    URL      string
    Settings string
    Tag      string

    Skip  bool              // Skip this folder?
    Main  string            // The main file
    Hooks map[string]string // Hooks mapped to functions
}

type PluginLang interface {
    GetName() string
    GetExts() []string

    Init() error
    AddPlugin(meta PluginMeta) (*Plugin, error)
    //AddHook(name string, handler interface{}) error
    //RemoveHook(name string, handler interface{})
    //RunHook(name string, data interface{}) interface{}
    //RunVHook(name string data ...interface{}) interface{}
}

/*
var ext = filepath.Ext(pluginFile.Name())
if ext == ".txt" || ext == ".go" {
    continue
}
*/

func InitPluginLangs() error {
    for _, pluginLang := range pluginLangs {
        pluginLang.Init()
    }
    pluginList, err := GetPluginFiles()
    if err != nil {
        return err
    }

    for _, pluginItem := range pluginList {
        pluginFile, err := ioutil.ReadFile("./extend/" + pluginItem + "/plugin.json")
        if err != nil {
            return err
        }

        var plugin PluginMeta
        err = json.Unmarshal(pluginFile, &plugin)
        if err != nil {
            return err
        }
        if plugin.Skip {
            continue
        }

        e := func(field, name string) error {
            return errors.New("The " + field + " field must not be blank on plugin '" + name + "'")
        }
        if plugin.UName == "" {
            return e("UName", pluginItem)
        }
        if plugin.Name == "" {
            return e("Name", pluginItem)
        }
        if plugin.Author == "" {
            return e("Author", pluginItem)
        }
        if plugin.Main == "" {
            return errors.New("Couldn't find a main file for plugin '" + pluginItem + "'")
        }

        ext := filepath.Ext(plugin.Main)
        pluginLang, err := ExtToPluginLang(ext)
        if err != nil {
            return err
        }
        pplugin, err := pluginLang.AddPlugin(plugin)
        if err != nil {
            return err
        }
        Plugins[plugin.UName] = pplugin
    }
    return nil
}

func GetPluginFiles() (pluginList []string, err error) {
    pluginFiles, err := ioutil.ReadDir("./extend")
    if err != nil {
        return nil, err
    }
    for _, pluginFile := range pluginFiles {
        if !pluginFile.IsDir() {
            continue
        }
        pluginList = append(pluginList, pluginFile.Name())
    }
    return pluginList, nil
}

func ExtToPluginLang(ext string) (PluginLang, error) {
    for _, pluginLang := range pluginLangs {
        for _, registeredExt := range pluginLang.GetExts() {
            if registeredExt == ext {
                return pluginLang, nil
            }
        }
    }
    return nil, errors.New("No plugin lang handlers are capable of handling extension '" + ext + "'")
}