Initial commit

plugin.go

@@ -0,0 +1,95 @@
+// maubot - A plugin-based Matrix bot system written in Go.
+// Copyright (C) 2018 Tulir Asokan
+//
+// This program is free software: you can redistribute it and/or modify
+// it under the terms of the GNU Affero General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+//
+// This program is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU Affero General Public License for more details.
+//
+// You should have received a copy of the GNU Affero General Public License
+// along with this program.  If not, see <https://www.gnu.org/licenses/>.
+
+package maubot
+
+import (
+	"fmt"
+	"plugin"
+
+	"maubot.xyz/database"
+	"maubot.xyz/matrix"
+)
+
+type Plugin interface {
+	Start()
+	Stop()
+}
+
+type PluginWrapper struct {
+	Plugin
+	Creator *PluginCreator
+	DB      *database.Plugin
+}
+
+type PluginCreatorFunc func(bot *Bot, info *database.Plugin, client *matrix.Client) Plugin
+
+type PluginCreator struct {
+	Create  PluginCreatorFunc
+	Name    string
+	Version string
+	Path    string
+}
+
+func LoadPlugin(path string) (*PluginCreator, error) {
+	rawPlugin, err := plugin.Open(path)
+	if err != nil {
+		return nil, fmt.Errorf("failed to open: %v", err)
+	}
+
+	pluginCreatorSymbol, err := rawPlugin.Lookup("Plugin")
+	if err == nil {
+		pluginCreator, ok := pluginCreatorSymbol.(*PluginCreator)
+		if ok {
+			pluginCreator.Path = path
+			return pluginCreator, nil
+		}
+	}
+
+	pluginCreatorFuncSymbol, err := rawPlugin.Lookup("Create")
+	if err != nil {
+		return nil, fmt.Errorf("symbol \"Create\" not found: %v", err)
+	}
+	pluginCreatorFunc, ok := pluginCreatorFuncSymbol.(PluginCreatorFunc)
+	if !ok {
+		return nil, fmt.Errorf("symbol \"Create\" does not implement maubot.PluginCreator")
+	}
+
+	nameSymbol, err := rawPlugin.Lookup("Name")
+	if err != nil {
+		return nil, fmt.Errorf("symbol \"Name\" not found: %v", err)
+	}
+	name, ok := nameSymbol.(string)
+	if !ok {
+		return nil, fmt.Errorf("symbol \"Name\" is not a string")
+	}
+
+	versionSymbol, err := rawPlugin.Lookup("Version")
+	if err != nil {
+		return nil, fmt.Errorf("symbol \"Version\" not found: %v", err)
+	}
+	version, ok := versionSymbol.(string)
+	if !ok {
+		return nil, fmt.Errorf("symbol \"Version\" is not a string")
+	}
+
+	return &PluginCreator{
+		Create:  pluginCreatorFunc,
+		Name:    name,
+		Version: version,
+		Path:    path,
+	}, nil
+}