Fix MessageHandle memory leak on send - #53

Author: matrober-uk

mqjms/ConsumerImpl.go

@@ -15,6 +15,7 @@ import (
 	"runtime"
 	"strconv"
 	"strings"
+	"sync"
 
 	"github.com/ibm-messaging/mq-golang-jms20/jms20subset"
 	ibmmq "github.com/ibm-messaging/mq-golang/v5/ibmmq"
@@ -109,24 +110,7 @@ func (consumer ConsumerImpl) receiveInternal(gmo *ibmmq.MQGMO) (jms20subset.Mess
 		// Set a finalizer on the message handle to allow it to be deleted
 		// when it is no longer referenced by an active object, to reduce/prevent
 		// memory leaks.
-		runtime.SetFinalizer(&thisMsgHandle, func(msgHandle *ibmmq.MQMessageHandle) {
-			consumer.ctx.ctxLock.Lock()
-			dmho := ibmmq.NewMQDMHO()
-			err := msgHandle.DltMH(dmho)
-			if err != nil {
-
-				mqret := err.(*ibmmq.MQReturn)
-
-				if mqret.MQRC == ibmmq.MQRC_HCONN_ERROR {
-					// Expected if the connection is closed before the finalizer executes
-					// (at which point it should get tidied up automatically by the connection)
-				} else {
-					fmt.Println("DltMH finalizer", err)
-				}
-
-			}
-			consumer.ctx.ctxLock.Unlock()
-		})
+		setMessageHandlerFinalizer(thisMsgHandle, consumer.ctx.ctxLock)
 
 		// Message received successfully (without error).
 		// Determine on the basis of the format field what sort of message to create.
@@ -198,6 +182,36 @@ func (consumer ConsumerImpl) receiveInternal(gmo *ibmmq.MQGMO) (jms20subset.Mess
 	return msg, jmsErr
 }
 
+/*
+ * Set a finalizer on the message handle to allow it to be deleted
+ * when it is no longer referenced by an active object, to reduce/prevent
+ * memory leaks.
+ */
+func setMessageHandlerFinalizer(thisMsgHandle ibmmq.MQMessageHandle, ctxLock *sync.Mutex) {
+
+	runtime.SetFinalizer(&thisMsgHandle, func(msgHandle *ibmmq.MQMessageHandle) {
+		ctxLock.Lock()
+		defer ctxLock.Unlock()
+
+		dmho := ibmmq.NewMQDMHO()
+		err := msgHandle.DltMH(dmho)
+		if err != nil {
+
+			mqret := err.(*ibmmq.MQReturn)
+
+			if mqret.MQRC == ibmmq.MQRC_HCONN_ERROR {
+				// Expected if the connection is closed before the finalizer executes
+				// (at which point it should get tidied up automatically by the connection)
+			} else {
+				fmt.Println("DltMH finalizer", err)
+			}
+
+		}
+
+	})
+
+}
+
 // ReceiveStringBodyNoWait implements the IBM MQ logic necessary to receive a
 // message from a Destination and return its body as a string.
 //

mqjms/ContextImpl.go

@@ -183,7 +183,7 @@ func (ctx ContextImpl) CreateTextMessage() jms20subset.TextMessage {
 	defer ctx.ctxLock.Unlock()
 
 	var bodyStr *string
-	thisMsgHandle := createMsgHandle(ctx.qMgr)
+	thisMsgHandle := ctx.createMsgHandle(ctx.qMgr)
 
 	return &TextMessageImpl{
 		bodyStr: bodyStr,
@@ -195,11 +195,16 @@ func (ctx ContextImpl) CreateTextMessage() jms20subset.TextMessage {
 
 // createMsgHandle creates a new message handle object that can be used to
 // store and retrieve message properties.
-func createMsgHandle(qMgr ibmmq.MQQueueManager) ibmmq.MQMessageHandle {
+func (ctx ContextImpl) createMsgHandle(qMgr ibmmq.MQQueueManager) ibmmq.MQMessageHandle {
 
 	cmho := ibmmq.NewMQCMHO()
 	thisMsgHandle, err := qMgr.CrtMH(cmho)
 
+	// Set a finalizer on the message handle to allow it to be deleted
+	// when it is no longer referenced by an active object, to reduce/prevent
+	// memory leaks.
+	setMessageHandlerFinalizer(thisMsgHandle, ctx.ctxLock)
+
 	if err != nil {
 		// No easy way to pass this error back to the application without
 		// changing the function signature, which could break existing
@@ -220,7 +225,7 @@ func (ctx ContextImpl) CreateTextMessageWithString(txt string) jms20subset.TextM
 	ctx.ctxLock.Lock()
 	defer ctx.ctxLock.Unlock()
 
-	thisMsgHandle := createMsgHandle(ctx.qMgr)
+	thisMsgHandle := ctx.createMsgHandle(ctx.qMgr)
 
 	msg := &TextMessageImpl{
 		bodyStr: &txt,
@@ -241,7 +246,7 @@ func (ctx ContextImpl) CreateBytesMessage() jms20subset.BytesMessage {
 	defer ctx.ctxLock.Unlock()
 
 	var thisBodyBytes *[]byte
-	thisMsgHandle := createMsgHandle(ctx.qMgr)
+	thisMsgHandle := ctx.createMsgHandle(ctx.qMgr)
 
 	return &BytesMessageImpl{
 		bodyBytes: thisBodyBytes,
@@ -259,7 +264,7 @@ func (ctx ContextImpl) CreateBytesMessageWithBytes(bytes []byte) jms20subset.Byt
 	ctx.ctxLock.Lock()
 	defer ctx.ctxLock.Unlock()
 
-	thisMsgHandle := createMsgHandle(ctx.qMgr)
+	thisMsgHandle := ctx.createMsgHandle(ctx.qMgr)
 
 	return &BytesMessageImpl{
 		bodyBytes: &bytes,