From ebfab42a5090403e1f61e34c8c6fba731f61fea2 Mon Sep 17 00:00:00 2001
From: Chris Lu <chris.lu@gmail.com>
Date: Mon, 20 Apr 2020 00:08:47 -0700
Subject: [PATCH] refactoring

---
 weed/filer2/filer_notify.go             | 49 --------------
 weed/server/filer_grpc_server_listen.go | 85 ++++++++++++++-----------
 2 files changed, 49 insertions(+), 85 deletions(-)

diff --git a/weed/filer2/filer_notify.go b/weed/filer2/filer_notify.go
index ac7ae4e4c..e5356472a 100644
--- a/weed/filer2/filer_notify.go
+++ b/weed/filer2/filer_notify.go
@@ -1,7 +1,6 @@
 package filer2
 
 import (
-	"bytes"
 	"fmt"
 	"strings"
 	"time"
@@ -79,51 +78,3 @@ func (f *Filer) logFlushFunc(startTime, stopTime time.Time, buf []byte) {
 		glog.V(0).Infof("log write failed %s: %v", targetFile, err)
 	}
 }
-
-func (f *Filer) ReadLogBuffer(lastReadTime time.Time, eachEventFn func(fullpath string, eventNotification *filer_pb.EventNotification) error) (newLastReadTime time.Time, err error) {
-
-	var bytesBuf *bytes.Buffer
-	bytesBuf = f.MetaLogBuffer.ReadFromBuffer(lastReadTime)
-	if bytesBuf == nil {
-		return
-	}
-	defer f.MetaLogBuffer.ReleaseMeory(bytesBuf)
-	buf := bytesBuf.Bytes()
-	var processedTs int64
-
-	for pos := 0; pos+4 < len(buf); {
-
-		size := util.BytesToUint32(buf[pos : pos+4])
-		entryData := buf[pos+4 : pos+4+int(size)]
-
-		logEntry := &filer_pb.LogEntry{}
-		err = proto.Unmarshal(entryData, logEntry)
-		if err != nil {
-			glog.Errorf("unexpected unmarshal filer_pb.LogEntry: %v", err)
-			return lastReadTime, fmt.Errorf("unexpected unmarshal filer_pb.LogEntry: %v", err)
-		}
-
-		event := &filer_pb.SubscribeMetadataResponse{}
-		err = proto.Unmarshal(logEntry.Data, event)
-		if err != nil {
-			glog.Errorf("unexpected unmarshal filer_pb.SubscribeMetadataResponse: %v", err)
-			return lastReadTime, fmt.Errorf("unexpected unmarshal filer_pb.SubscribeMetadataResponse: %v", err)
-		}
-
-		err = eachEventFn(event.Directory, event.EventNotification)
-
-		processedTs = logEntry.TsNs
-
-		if err != nil {
-			newLastReadTime = time.Unix(0, processedTs)
-			return
-		}
-
-		pos += 4 + int(size)
-
-	}
-
-	newLastReadTime = time.Unix(0, processedTs)
-	return
-
-}
diff --git a/weed/server/filer_grpc_server_listen.go b/weed/server/filer_grpc_server_listen.go
index e3de57145..6dd423007 100644
--- a/weed/server/filer_grpc_server_listen.go
+++ b/weed/server/filer_grpc_server_listen.go
@@ -1,9 +1,12 @@
 package weed_server
 
 import (
+	"fmt"
 	"strings"
 	"time"
 
+	"github.com/golang/protobuf/proto"
+
 	"github.com/chrislusf/seaweedfs/weed/filer2"
 	"github.com/chrislusf/seaweedfs/weed/glog"
 	"github.com/chrislusf/seaweedfs/weed/pb/filer_pb"
@@ -23,48 +26,58 @@ func (fs *FilerServer) SubscribeMetadata(req *filer_pb.SubscribeMetadataRequest,
 		lastReadTime = time.Unix(0, req.SinceNs)
 	}
 
-	var readErr error
-	for {
+	eachEventNotificationFn := func(dirPath string, eventNotification *filer_pb.EventNotification) error {
 
-		lastReadTime, readErr = fs.filer.ReadLogBuffer(lastReadTime, func(dirPath string, eventNotification *filer_pb.EventNotification) error {
-
-			// get complete path to the file or directory
-			var entryName string
-			if eventNotification.OldEntry != nil {
-				entryName = eventNotification.OldEntry.Name
-			} else if eventNotification.NewEntry != nil {
-				entryName = eventNotification.NewEntry.Name
-			}
-
-			fullpath := util.Join(dirPath, entryName)
-
-			// skip on filer internal meta logs
-			if strings.HasPrefix(fullpath, filer2.SystemLogDir) {
-				return nil
-			}
-
-			if !strings.HasPrefix(fullpath, req.PathPrefix) {
-				return nil
-			}
-
-			message := &filer_pb.SubscribeMetadataResponse{
-				Directory:         dirPath,
-				EventNotification: eventNotification,
-			}
-			if err := stream.Send(message); err != nil {
-				return err
-			}
-			return nil
-		})
-		if readErr != nil {
-			glog.V(0).Infof("=> client %v: %+v", clientName, readErr)
-			return readErr
+		// get complete path to the file or directory
+		var entryName string
+		if eventNotification.OldEntry != nil {
+			entryName = eventNotification.OldEntry.Name
+		} else if eventNotification.NewEntry != nil {
+			entryName = eventNotification.NewEntry.Name
 		}
 
+		fullpath := util.Join(dirPath, entryName)
+
+		// skip on filer internal meta logs
+		if strings.HasPrefix(fullpath, filer2.SystemLogDir) {
+			return nil
+		}
+
+		if !strings.HasPrefix(fullpath, req.PathPrefix) {
+			return nil
+		}
+
+		message := &filer_pb.SubscribeMetadataResponse{
+			Directory:         dirPath,
+			EventNotification: eventNotification,
+		}
+		if err := stream.Send(message); err != nil {
+			glog.V(0).Infof("=> client %v: %+v", clientName, err)
+			return err
+		}
+		return nil
+	}
+
+	_, err := fs.filer.MetaLogBuffer.LoopProcessLogData(lastReadTime, func() bool {
 		fs.listenersLock.Lock()
 		fs.listenersCond.Wait()
 		fs.listenersLock.Unlock()
-	}
+		return true
+	}, func(logEntry *filer_pb.LogEntry) error {
+		event := &filer_pb.SubscribeMetadataResponse{}
+		if err := proto.Unmarshal(logEntry.Data, event); err != nil {
+			glog.Errorf("unexpected unmarshal filer_pb.SubscribeMetadataResponse: %v", err)
+			return fmt.Errorf("unexpected unmarshal filer_pb.SubscribeMetadataResponse: %v", err)
+		}
+
+		if err := eachEventNotificationFn(event.Directory, event.EventNotification); err != nil {
+			return err
+		}
+
+		return nil
+	})
+
+	return err
 
 }