Add image caching to ImagePreviewImageLoader

ScrollableImagePreviewView being a RecyclerView may reattache its
children multiple times and rely on the ImageLoader to implement any
image retrival optimizations.

Fix: 269797062
Test: manual test, unit tests
Change-Id: I256f4a78a677e939f717fee5dd82492ec572bc65

3 files changed, 105 insertions, 0 deletions

diff --git a/java/tests/src/com/android/intentresolver/ImagePreviewImageLoaderTest.kt b/java/tests/src/com/android/intentresolver/ImagePreviewImageLoaderTest.kt
new file mode 100644
index 00000000..f327e19e
--- /dev/null
+++ b/java/tests/src/com/android/intentresolver/ImagePreviewImageLoaderTest.kt
@@ -0,0 +1,101 @@
+/*
+ * Copyright (C) 2023 The Android Open Source Project
+ *
+ * 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.
+ */
+
+package com.android.intentresolver
+
+import android.content.ContentResolver
+import android.content.Context
+import android.content.res.Resources
+import android.net.Uri
+import android.util.Size
+import androidx.lifecycle.Lifecycle
+import kotlinx.coroutines.Dispatchers
+import kotlinx.coroutines.ExperimentalCoroutinesApi
+import kotlinx.coroutines.test.TestCoroutineScheduler
+import kotlinx.coroutines.test.UnconfinedTestDispatcher
+import kotlinx.coroutines.test.resetMain
+import kotlinx.coroutines.test.runTest
+import kotlinx.coroutines.test.setMain
+import org.junit.After
+import org.junit.Before
+import org.junit.Test
+import org.mockito.Mockito.never
+import org.mockito.Mockito.times
+import org.mockito.Mockito.verify
+
+@OptIn(ExperimentalCoroutinesApi::class)
+class ImagePreviewImageLoaderTest {
+    private val imageSize = Size(300, 300)
+    private val uriOne = Uri.parse("content://org.package.app/image-1.png")
+    private val uriTwo = Uri.parse("content://org.package.app/image-2.png")
+    private val contentResolver = mock<ContentResolver>()
+    private val resources = mock<Resources> {
+        whenever(getDimensionPixelSize(R.dimen.chooser_preview_image_max_dimen))
+            .thenReturn(imageSize.width)
+    }
+    private val context = mock<Context> {
+        whenever(this.resources).thenReturn(this@ImagePreviewImageLoaderTest.resources)
+        whenever(this.contentResolver).thenReturn(this@ImagePreviewImageLoaderTest.contentResolver)
+    }
+    private val scheduler = TestCoroutineScheduler()
+    private val lifecycleOwner = TestLifecycleOwner()
+    private val dispatcher = UnconfinedTestDispatcher(scheduler)
+    private val testSubject = ImagePreviewImageLoader(
+        context, lifecycleOwner.lifecycle, 1, dispatcher
+    )
+
+    @Before
+    fun setup() {
+        Dispatchers.setMain(dispatcher)
+        lifecycleOwner.state = Lifecycle.State.CREATED
+    }
+
+    @After
+    fun cleanup() {
+        lifecycleOwner.state = Lifecycle.State.DESTROYED
+        Dispatchers.resetMain()
+    }
+
+    @Test
+    fun test_prePopulate() = runTest {
+        testSubject.prePopulate(listOf(uriOne, uriTwo))
+
+        verify(contentResolver, times(1)).loadThumbnail(uriOne, imageSize, null)
+        verify(contentResolver, never()).loadThumbnail(uriTwo, imageSize, null)
+
+        testSubject(uriOne)
+        verify(contentResolver, times(1)).loadThumbnail(uriOne, imageSize, null)
+    }
+
+    @Test
+    fun test_invoke_return_cached_image() = runTest {
+        testSubject(uriOne)
+        testSubject(uriOne)
+
+        verify(contentResolver, times(1)).loadThumbnail(any(), any(), anyOrNull())
+    }
+
+    @Test
+    fun test_invoke_old_records_evicted_from_the_cache() = runTest {
+        testSubject(uriOne)
+        testSubject(uriTwo)
+        testSubject(uriTwo)
+        testSubject(uriOne)
+
+        verify(contentResolver, times(2)).loadThumbnail(uriOne, imageSize, null)
+        verify(contentResolver, times(1)).loadThumbnail(uriTwo, imageSize, null)
+    }
+}
diff --git a/java/tests/src/com/android/intentresolver/MockitoKotlinHelpers.kt b/java/tests/src/com/android/intentresolver/MockitoKotlinHelpers.kt
index 159c6d6a..aaa7a282 100644
--- a/java/tests/src/com/android/intentresolver/MockitoKotlinHelpers.kt
+++ b/java/tests/src/com/android/intentresolver/MockitoKotlinHelpers.kt
@@ -26,6 +26,7 @@ package com.android.intentresolver
 
 import org.mockito.ArgumentCaptor
 import org.mockito.ArgumentMatcher
+import org.mockito.ArgumentMatchers
 import org.mockito.Mockito
 import org.mockito.stubbing.OngoingStubbing
 
@@ -144,3 +145,5 @@ inline fun <reified T : Any> withArgCaptor(block: KotlinArgumentCaptor<T>.() ->
  */
 inline fun <reified T : Any> captureMany(block: KotlinArgumentCaptor<T>.() -> Unit): List<T> =
     kotlinArgumentCaptor<T>().apply{ block() }.allValues
+
+inline fun <reified T> anyOrNull() = ArgumentMatchers.argThat(ArgumentMatcher<T?> { true })
diff --git a/java/tests/src/com/android/intentresolver/TestPreviewImageLoader.kt b/java/tests/src/com/android/intentresolver/TestPreviewImageLoader.kt
index fd617fdd..cfe041dd 100644
--- a/java/tests/src/com/android/intentresolver/TestPreviewImageLoader.kt
+++ b/java/tests/src/com/android/intentresolver/TestPreviewImageLoader.kt
@@ -34,4 +34,5 @@ internal class TestPreviewImageLoader(
     }
 
     override suspend fun invoke(uri: Uri): Bitmap? = imageOverride() ?: imageLoader(uri)
+    override fun prePopulate(uris: List<Uri>) = Unit
 }