From 14eb008f51033748d22f6464409f27f8e9e753e6 Mon Sep 17 00:00:00 2001
From: Julien Semaan <jul.semaan@gmail.com>
Date: Tue, 1 Dec 2020 13:34:50 -0500
Subject: [PATCH] fix mem leak in peers table due to
 https://github.com/fyne-io/fyne/issues/735

---
 guiwrapper/main.go      |  4 +--
 guiwrapper/start_app.go | 15 ++++++----
 guiwrapper/table.go     | 64 +++++++++++++++++++++++++++++++++++++++++
 guiwrapper/util.go      | 21 --------------
 4 files changed, 75 insertions(+), 29 deletions(-)
 create mode 100644 guiwrapper/table.go

diff --git a/guiwrapper/main.go b/guiwrapper/main.go
index df016df..81d6ceb 100644
--- a/guiwrapper/main.go
+++ b/guiwrapper/main.go
@@ -93,7 +93,7 @@ func checkTunnelStatus() {
 				}
 			} else if fails >= maxRpcFails {
 				statusLabel.SetText("Too many failures communicating with RPC server. Tunnel seems to be dead. Please restart the client.")
-				peersTable.SetContent(widget.NewLabel(""))
+				peersTableContainer.SetContent(widget.NewLabel(""))
 			} else {
 				fmt.Println("Failed to contact tunnel for status update")
 				statusLabel.SetText("Tunnel seems to be inactive...")
@@ -108,7 +108,7 @@ func checkTunnelStatus() {
 				return
 			} else {
 				statusLabel.SetText(messages[status])
-				//UpdatePeers(ctx, rpc)
+				UpdatePeers(ctx, rpc)
 			}
 		}
 
diff --git a/guiwrapper/start_app.go b/guiwrapper/start_app.go
index 8388cd9..ba513a1 100644
--- a/guiwrapper/start_app.go
+++ b/guiwrapper/start_app.go
@@ -20,7 +20,8 @@ import (
 var spacePlaceholder = "                          "
 
 var statusLabel *widget.Label
-var peersTable *widget.Card
+var peersTableContainer *widget.Card
+var peersTable = NewTable()
 
 var restartBtn *widget.Button
 
@@ -198,8 +199,8 @@ func PromptCredentials(tabs *container.AppTabs, callback func(bool)) {
 func PostConnect(tabs *container.AppTabs) {
 	statusLabel = widget.NewLabel("Opening tunnel process")
 	statusLabel.Wrapping = fyne.TextWrapWord
-	peersTable = widget.NewCard("Peers", "", widget.NewVBox())
-	tabs.Items[0].Content = widget.NewVBox(statusLabel, restartBtn, peersTable)
+	peersTableContainer = widget.NewCard("Peers", "", widget.NewVBox())
+	tabs.Items[0].Content = widget.NewVBox(statusLabel, restartBtn, peersTableContainer)
 	if len(tabs.Items) > 1 {
 		tabs.RemoveIndex(1)
 	}
@@ -209,7 +210,7 @@ func PostConnect(tabs *container.AppTabs) {
 func UpdatePeers(ctx context.Context, rpc wgrpc.WGServiceClient) {
 	peers, err := rpc.GetPeers(ctx, &wgrpc.PeersRequest{})
 	if err != nil {
-		peersTable.SetContent(widget.NewLabel("Failed to obtain peers from local wireguard server: " + err.Error()))
+		peersTableContainer.SetContent(widget.NewLabel("Failed to obtain peers from local wireguard server: " + err.Error()))
 		return
 	}
 
@@ -222,8 +223,10 @@ func UpdatePeers(ctx context.Context, rpc wgrpc.WGServiceClient) {
 		peersInfos = append(peersInfos, []string{peer.Hostname, peer.IpAddress, peer.Status})
 	}
 
-	peersTable.SetContent(makeTable(
+	peersTable.Update(
 		[]string{"Host", "IP address", "State"},
 		peersInfos,
-	))
+	)
+
+	peersTableContainer.SetContent(peersTable.GetContainer())
 }
diff --git a/guiwrapper/table.go b/guiwrapper/table.go
new file mode 100644
index 0000000..859ee79
--- /dev/null
+++ b/guiwrapper/table.go
@@ -0,0 +1,64 @@
+package main
+
+import (
+	"fyne.io/fyne"
+	"fyne.io/fyne/container"
+	"fyne.io/fyne/widget"
+)
+
+type Table struct {
+	columnsRows [][]*widget.Label
+	columns     []*fyne.Container
+	container   *fyne.Container
+}
+
+func NewTable() *Table {
+	return &Table{columnsRows: [][]*widget.Label{}, columns: []*fyne.Container{}}
+}
+
+func (t *Table) Update(headings []string, rows [][]string) {
+	columnsData := rowsToColumns(headings, rows)
+	for i, col := range columnsData {
+		if len(t.columnsRows) <= i {
+			t.columnsRows = append(t.columnsRows, []*widget.Label{})
+		}
+		row := t.columnsRows[i]
+		columnData := append([]string{headings[i]}, col...)
+		for j, elem := range columnData {
+			if len(row) <= j {
+				row = append(row, widget.NewLabel(elem))
+			}
+			row[j].Text = elem
+		}
+		t.columnsRows[i] = row
+
+		if len(t.columns) <= i {
+			t.columns = append(t.columns, container.NewGridWithColumns(1, []fyne.CanvasObject{}...))
+		}
+
+		objects := []fyne.CanvasObject{}
+		for _, o := range t.columnsRows[i] {
+			objects = append(objects, o)
+		}
+
+		column := t.columns[i]
+		column.Objects = objects
+		column.Refresh()
+	}
+
+	objects := []fyne.CanvasObject{}
+	for _, o := range t.columns {
+		objects = append(objects, o)
+	}
+
+	if t.container == nil {
+		t.container = container.NewHBox(objects...)
+	} else {
+		t.container.Objects = objects
+		t.container.Refresh()
+	}
+}
+
+func (t *Table) GetContainer() *fyne.Container {
+	return t.container
+}
diff --git a/guiwrapper/util.go b/guiwrapper/util.go
index 83e6b05..088fa56 100644
--- a/guiwrapper/util.go
+++ b/guiwrapper/util.go
@@ -1,26 +1,5 @@
 package main
 
-import (
-	"fyne.io/fyne"
-	"fyne.io/fyne/container"
-	"fyne.io/fyne/widget"
-)
-
-func makeTable(headings []string, rows [][]string) *fyne.Container {
-	columns := rowsToColumns(headings, rows)
-	objects := []fyne.CanvasObject{}
-	for i, col := range columns {
-		elems := []fyne.CanvasObject{
-			widget.NewLabelWithStyle(headings[i], fyne.TextAlignLeading, fyne.TextStyle{Bold: true}),
-		}
-		for _, elem := range col {
-			elems = append(elems, widget.NewLabel(elem))
-		}
-		objects = append(objects, container.NewGridWithColumns(1, elems...))
-	}
-	return container.NewHBox(objects...)
-}
-
 func rowsToColumns(headings []string, rows [][]string) [][]string {
 	columns := make([][]string, len(headings))
 	for _, row := range rows {