!304 修复多线程图片加载出现空白问题

Merge pull request !304 from baofeng/master

CHANGELOG.md

@@ -5,6 +5,7 @@
 - 支持多种组合变换
 - 提供清理缓存能力
 - 修复preLoad接口失效
+- 修复多线程图片加载出现空白问题
 
 ## 2.2.0-rc.2
 - ImageKnife支持下采样

library/src/main/ets/components/cache/CustomSendableMap.ets

@@ -13,6 +13,7 @@
  * limitations under the License.
  */
 import { collections } from '@kit.ArkTS'
+import { AsyncLock } from '../imageknife/utils/base/AsyncLock';
 import { DiskCacheEntry } from './DiskCacheEntry';
 
 @Sendable
@@ -38,16 +39,24 @@ export class CustomSendableMap {
   }
 
   //  添加键值对
-  put(key: string, value: DiskCacheEntry): DiskCacheEntry | undefined{
+  async put(key: string, value: DiskCacheEntry): Promise<DiskCacheEntry | undefined>{
     if (key == null || value == null) {
       throw new Error('key or value is invalid,checking the parameter');
     }
-    let pre = this.map.get(key) as DiskCacheEntry | undefined;
+    const lock = new AsyncLock();
-    if (this.hasKey(key)) {
+    await lock.acquire()
-      this.map.delete(key)
+    try {
+      let pre = this.map.get(key) as DiskCacheEntry | undefined;
+      if (this.hasKey(key)) {
+        this.map.delete(key)
+      }
+      this.map.set(key, value);
+      return pre;
+    } catch (e) {
+       throw new Error('put value error');
+    } finally {
+      lock.release();
     }
-    this.map.set(key, value);
-    return pre
   }
 
   // 去除键值，(去除键数据中的键名及对应的值)

library/src/main/ets/components/imageknife/utils/base/AsyncLock.ts

@@ -0,0 +1,37 @@
+/*
+ * Copyright (C) 2024 Huawei Device Co., Ltd.
+ * Licensed under the Apache License, Version 2.0 (the 'License');
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an 'AS IS' BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+export class AsyncLock {
+  private locked: boolean = false;
+  private waitingList: Array<Function> = [];
+
+
+  async acquire() {
+    if (this.locked) {
+      await new Promise((resolve) => {
+        this.waitingList.push(resolve);
+      });
+    }
+    this.locked = true;
+  }
+
+  release() {
+    this.locked = false;
+    if (this.waitingList.length > 0) {
+      let resolve = this.waitingList.shift();
+      resolve && resolve();
+    }
+  }
+}