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1 /*
<lambda>null2  * Copyright (C) 2022 The Android Open Source Project
3  *
4  * Licensed under the Apache License, Version 2.0 (the "License");
5  * you may not use this file except in compliance with the License.
6  * You may obtain a copy of the License at
7  *
8  *      http://www.apache.org/licenses/LICENSE-2.0
9  *
10  * Unless required by applicable law or agreed to in writing, software
11  * distributed under the License is distributed on an "AS IS" BASIS,
12  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13  * See the License for the specific language governing permissions and
14  * limitations under the License.
15  */
16 
17 package com.android.intentresolver
18 
19 import android.content.Context
20 import android.graphics.Bitmap
21 import android.net.Uri
22 import android.util.Size
23 import androidx.annotation.GuardedBy
24 import androidx.annotation.VisibleForTesting
25 import androidx.collection.LruCache
26 import androidx.lifecycle.Lifecycle
27 import androidx.lifecycle.coroutineScope
28 import kotlinx.coroutines.CompletableDeferred
29 import kotlinx.coroutines.CoroutineDispatcher
30 import kotlinx.coroutines.Dispatchers
31 import kotlinx.coroutines.isActive
32 import kotlinx.coroutines.launch
33 import java.util.function.Consumer
34 
35 @VisibleForTesting
36 class ImagePreviewImageLoader @JvmOverloads constructor(
37     private val context: Context,
38     private val lifecycle: Lifecycle,
39     cacheSize: Int,
40     private val dispatcher: CoroutineDispatcher = Dispatchers.IO
41 ) : ImageLoader {
42 
43     private val thumbnailSize: Size =
44         context.resources.getDimensionPixelSize(R.dimen.chooser_preview_image_max_dimen).let {
45             Size(it, it)
46         }
47 
48     @GuardedBy("self")
49     private val cache = LruCache<Uri, CompletableDeferred<Bitmap?>>(cacheSize)
50 
51     override suspend fun invoke(uri: Uri): Bitmap? = loadImageAsync(uri)
52 
53     override fun loadImage(uri: Uri, callback: Consumer<Bitmap?>) {
54         lifecycle.coroutineScope.launch {
55             val image = loadImageAsync(uri)
56             if (isActive) {
57                 callback.accept(image)
58             }
59         }
60     }
61 
62     override fun prePopulate(uris: List<Uri>) {
63         uris.asSequence().take(cache.maxSize()).forEach { uri ->
64             lifecycle.coroutineScope.launch {
65                 loadImageAsync(uri)
66             }
67         }
68     }
69 
70     private suspend fun loadImageAsync(uri: Uri): Bitmap? {
71         return synchronized(cache) {
72             cache.get(uri) ?: CompletableDeferred<Bitmap?>().also { result ->
73                 cache.put(uri, result)
74                 lifecycle.coroutineScope.launch(dispatcher) {
75                     result.loadBitmap(uri)
76                 }
77             }
78         }.await()
79     }
80 
81     private fun CompletableDeferred<Bitmap?>.loadBitmap(uri: Uri) {
82         val bitmap = runCatching {
83             context.contentResolver.loadThumbnail(uri,  thumbnailSize, null)
84         }.getOrNull()
85         complete(bitmap)
86     }
87 }
88