From 076bce8727d3f02cc3cbf6cdfb560a758185aaf3 Mon Sep 17 00:00:00 2001
From: "Jason A. Donenfeld" <Jason@zx2c4.com>
Date: Wed, 20 Mar 2019 02:18:05 -0600
Subject: ringlogger: introduce basic file ring logging

Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>
---
 ui/logview.go | 128 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 128 insertions(+)
 create mode 100644 ui/logview.go

(limited to 'ui/logview.go')

diff --git a/ui/logview.go b/ui/logview.go
new file mode 100644
index 00000000..e7a8a237
--- /dev/null
+++ b/ui/logview.go
@@ -0,0 +1,128 @@
+/* SPDX-License-Identifier: MIT
+ *
+ * Copyright (C) 2019 WireGuard LLC. All Rights Reserved.
+ */
+
+package ui
+
+import (
+	"errors"
+	"fmt"
+	"github.com/lxn/walk"
+	"github.com/lxn/win"
+	"golang.zx2c4.com/wireguard/windows/ringlogger"
+	"strings"
+	"syscall"
+	"time"
+	"unsafe"
+)
+
+type LogView struct {
+	walk.WidgetBase
+	logChan chan string
+}
+
+const (
+	TEM_APPENDTEXT = win.WM_USER + 6
+)
+
+func NewLogView(parent walk.Container, rl *ringlogger.Ringlogger) (*LogView, error) {
+	lc := make(chan string, 1024)
+	lv := &LogView{logChan: lc}
+
+	if err := walk.InitWidget(
+		lv,
+		parent,
+		"EDIT",
+		win.WS_TABSTOP|win.WS_VISIBLE|win.WS_VSCROLL|win.ES_MULTILINE|win.ES_WANTRETURN,
+		win.WS_EX_CLIENTEDGE); err != nil {
+		return nil, err
+	}
+	lv.setReadOnly(true)
+	lv.SendMessage(win.EM_SETLIMITTEXT, 4294967295, 0)
+
+	go func() {
+		var lines []ringlogger.FollowLine
+		cursor := ringlogger.CursorAll
+		for {
+			if lv.IsDisposed() {
+				return
+			}
+			lines, cursor = rl.FollowFromCursor(cursor)
+			sb := strings.Builder{}
+			for _, line := range lines {
+				sb.WriteString(fmt.Sprintf("%s: %s\r\n", line.Stamp.Format("2006-01-02 15:04:05.000000"), strings.ReplaceAll(line.Line, "\n", "\r\n")))
+			}
+			newLines := sb.String()
+			if len(newLines) > 0 {
+				lv.AppendText(newLines)
+			}
+			time.Sleep(300 * time.Millisecond)
+		}
+	}()
+	return lv, nil
+}
+
+func (*LogView) LayoutFlags() walk.LayoutFlags {
+	return walk.ShrinkableHorz | walk.ShrinkableVert | walk.GrowableHorz | walk.GrowableVert | walk.GreedyHorz | walk.GreedyVert
+}
+
+func (*LogView) MinSizeHint() walk.Size {
+	return walk.Size{20, 12}
+}
+
+func (*LogView) SizeHint() walk.Size {
+	return walk.Size{100, 100}
+}
+
+func (lv *LogView) setTextSelection(start, end int) {
+	lv.SendMessage(win.EM_SETSEL, uintptr(start), uintptr(end))
+}
+
+func (lv *LogView) textLength() int {
+	return int(lv.SendMessage(0x000E, uintptr(0), uintptr(0)))
+}
+
+func (lv *LogView) AppendText(value string) {
+	textLength := lv.textLength()
+	lv.setTextSelection(textLength, textLength)
+	lv.SendMessage(win.EM_REPLACESEL, 0, uintptr(unsafe.Pointer(syscall.StringToUTF16Ptr(value))))
+}
+
+func (lv *LogView) setReadOnly(readOnly bool) error {
+	if 0 == lv.SendMessage(win.EM_SETREADONLY, uintptr(win.BoolToBOOL(readOnly)), 0) {
+		return errors.New("fail to call EM_SETREADONLY")
+	}
+
+	return nil
+}
+
+func (lv *LogView) PostAppendText(value string) {
+	lv.logChan <- value
+	win.PostMessage(lv.Handle(), TEM_APPENDTEXT, 0, 0)
+}
+
+func (lv *LogView) Write(p []byte) (int, error) {
+	lv.PostAppendText(string(p) + "\r\n")
+	return len(p), nil
+}
+
+func (lv *LogView) WndProc(hwnd win.HWND, msg uint32, wParam, lParam uintptr) uintptr {
+	switch msg {
+	case win.WM_GETDLGCODE:
+		if wParam == win.VK_RETURN {
+			return win.DLGC_WANTALLKEYS
+		}
+
+		return win.DLGC_HASSETSEL | win.DLGC_WANTARROWS | win.DLGC_WANTCHARS
+	case TEM_APPENDTEXT:
+		select {
+		case value := <-lv.logChan:
+			lv.AppendText(value)
+		default:
+			return 0
+		}
+	}
+
+	return lv.WidgetBase.WndProc(hwnd, msg, wParam, lParam)
+}
-- 
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