Added embed server for plugin library

- Added embeded resources server for plugin library
- Added ztnc plugin for global area network
- Added wide mode for side wrapper

example/plugins/ztnc/mod/database/dbleveldb/dbleveldb.go

@@ -0,0 +1,152 @@
+package dbleveldb
+
+import (
+	"encoding/json"
+	"log"
+	"path/filepath"
+	"strings"
+	"sync"
+	"time"
+
+	"aroz.org/zoraxy/ztnc/mod/database/dbinc"
+	"github.com/syndtr/goleveldb/leveldb"
+	"github.com/syndtr/goleveldb/leveldb/util"
+)
+
+// Ensure the DB struct implements the Backend interface
+var _ dbinc.Backend = (*DB)(nil)
+
+type DB struct {
+	db               *leveldb.DB
+	Table            sync.Map      //For emulating table creation
+	batch            leveldb.Batch //Batch write
+	writeFlushTicker *time.Ticker  //Ticker for flushing data into disk
+	writeFlushStop   chan bool     //Stop channel for write flush ticker
+}
+
+func NewDB(path string) (*DB, error) {
+	//If the path is not a directory (e.g. /tmp/dbfile.db), convert the filename to directory
+	if filepath.Ext(path) != "" {
+		path = strings.ReplaceAll(path, ".", "_")
+	}
+
+	db, err := leveldb.OpenFile(path, nil)
+	if err != nil {
+		return nil, err
+	}
+
+	thisDB := &DB{
+		db:    db,
+		Table: sync.Map{},
+		batch: leveldb.Batch{},
+	}
+
+	//Create a ticker to flush data into disk every 1 seconds
+	writeFlushTicker := time.NewTicker(1 * time.Second)
+	writeFlushStop := make(chan bool)
+	go func() {
+		for {
+			select {
+			case <-writeFlushTicker.C:
+				if thisDB.batch.Len() == 0 {
+					//No flushing needed
+					continue
+				}
+				err = db.Write(&thisDB.batch, nil)
+				if err != nil {
+					log.Println("[LevelDB] Failed to flush data into disk: ", err)
+				}
+				thisDB.batch.Reset()
+			case <-writeFlushStop:
+				return
+			}
+		}
+	}()
+
+	thisDB.writeFlushTicker = writeFlushTicker
+	thisDB.writeFlushStop = writeFlushStop
+
+	return thisDB, nil
+}
+
+func (d *DB) NewTable(tableName string) error {
+	//Create a table entry in the sync.Map
+	d.Table.Store(tableName, true)
+	return nil
+}
+
+func (d *DB) TableExists(tableName string) bool {
+	_, ok := d.Table.Load(tableName)
+	return ok
+}
+
+func (d *DB) DropTable(tableName string) error {
+	d.Table.Delete(tableName)
+	iter := d.db.NewIterator(nil, nil)
+	defer iter.Release()
+
+	for iter.Next() {
+		key := iter.Key()
+		if filepath.Dir(string(key)) == tableName {
+			err := d.db.Delete(key, nil)
+			if err != nil {
+				return err
+			}
+		}
+	}
+
+	return nil
+}
+
+func (d *DB) Write(tableName string, key string, value interface{}) error {
+	data, err := json.Marshal(value)
+	if err != nil {
+		return err
+	}
+	d.batch.Put([]byte(filepath.ToSlash(filepath.Join(tableName, key))), data)
+	return nil
+}
+
+func (d *DB) Read(tableName string, key string, assignee interface{}) error {
+	data, err := d.db.Get([]byte(filepath.ToSlash(filepath.Join(tableName, key))), nil)
+	if err != nil {
+		return err
+	}
+	return json.Unmarshal(data, assignee)
+}
+
+func (d *DB) KeyExists(tableName string, key string) bool {
+	_, err := d.db.Get([]byte(filepath.ToSlash(filepath.Join(tableName, key))), nil)
+	return err == nil
+}
+
+func (d *DB) Delete(tableName string, key string) error {
+	return d.db.Delete([]byte(filepath.ToSlash(filepath.Join(tableName, key))), nil)
+}
+
+func (d *DB) ListTable(tableName string) ([][][]byte, error) {
+	iter := d.db.NewIterator(util.BytesPrefix([]byte(tableName+"/")), nil)
+	defer iter.Release()
+
+	var result [][][]byte
+	for iter.Next() {
+		key := iter.Key()
+		//The key contains the table name as prefix. Trim it before returning
+		value := iter.Value()
+		result = append(result, [][]byte{[]byte(strings.TrimPrefix(string(key), tableName+"/")), value})
+	}
+
+	err := iter.Error()
+	if err != nil {
+		return nil, err
+	}
+	return result, nil
+}
+
+func (d *DB) Close() {
+	//Write the remaining data in batch back into disk
+	d.writeFlushStop <- true
+	d.writeFlushTicker.Stop()
+	d.db.Write(&d.batch, nil)
+	d.db.Close()
+}