From 9449e0a8a676554e7b6bf2329ed2e431fc09adbf Mon Sep 17 00:00:00 2001
From: Hajime Hoshi <hajimehoshi@gmail.com>
Date: Fri, 25 Oct 2024 14:52:02 +0900
Subject: [PATCH] Revert "text/v2: remove faceWithCache's mutex"

This reverts commit d5c6fd174f6834166137a7a8611bf6c451ea6f56.

Reason: CacheGlyphs and Measure should be concurrent safe.
---
 text/v2/goxcache.go | 15 +++++++++++++++
 1 file changed, 15 insertions(+)

diff --git a/text/v2/goxcache.go b/text/v2/goxcache.go
index bcc4f6d10..b871b78c0 100644
--- a/text/v2/goxcache.go
+++ b/text/v2/goxcache.go
@@ -16,6 +16,7 @@ package text
 
 import (
 	"image"
+	"sync"
 
 	"golang.org/x/image/font"
 	"golang.org/x/image/math/fixed"
@@ -43,6 +44,8 @@ type faceWithCache struct {
 	glyphBoundsCache  map[rune]glyphBoundsCacheValue
 	glyphAdvanceCache map[rune]glyphAdvanceCacheValue
 	kernCache         map[kernCacheKey]fixed.Int26_6
+
+	m sync.Mutex
 }
 
 func (f *faceWithCache) Close() error {
@@ -50,6 +53,9 @@ func (f *faceWithCache) Close() error {
 		return err
 	}
 
+	f.m.Lock()
+	defer f.m.Unlock()
+
 	f.glyphBoundsCache = nil
 	f.glyphAdvanceCache = nil
 	f.kernCache = nil
@@ -61,6 +67,9 @@ func (f *faceWithCache) Glyph(dot fixed.Point26_6, r rune) (dr image.Rectangle,
 }
 
 func (f *faceWithCache) GlyphBounds(r rune) (bounds fixed.Rectangle26_6, advance fixed.Int26_6, ok bool) {
+	f.m.Lock()
+	defer f.m.Unlock()
+
 	if v, ok := f.glyphBoundsCache[r]; ok {
 		return v.bounds, v.advance, v.ok
 	}
@@ -78,6 +87,9 @@ func (f *faceWithCache) GlyphBounds(r rune) (bounds fixed.Rectangle26_6, advance
 }
 
 func (f *faceWithCache) GlyphAdvance(r rune) (advance fixed.Int26_6, ok bool) {
+	f.m.Lock()
+	defer f.m.Unlock()
+
 	if v, ok := f.glyphAdvanceCache[r]; ok {
 		return v.advance, v.ok
 	}
@@ -94,6 +106,9 @@ func (f *faceWithCache) GlyphAdvance(r rune) (advance fixed.Int26_6, ok bool) {
 }
 
 func (f *faceWithCache) Kern(r0, r1 rune) fixed.Int26_6 {
+	f.m.Lock()
+	defer f.m.Unlock()
+
 	key := kernCacheKey{r0: r0, r1: r1}
 	if v, ok := f.kernCache[key]; ok {
 		return v