packages/flutter/test/painting/image_cache_test.dart

// Copyright 2014 The Flutter Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

// @dart = 2.8

import 'dart:ui' as ui;

import 'package:flutter/painting.dart';
import '../flutter_test_alternative.dart';

import '../rendering/rendering_tester.dart';
import 'mocks_for_image_cache.dart';

void main() {
  TestRenderingFlutterBinding();

  tearDown(() {
    imageCache.clear();
    imageCache.clearLiveImages();
    imageCache.maximumSize = 1000;
    imageCache.maximumSizeBytes = 10485760;
  });

  test('maintains cache size', () async {
    imageCache.maximumSize = 3;

    final TestImageInfo a = await extractOneFrame(TestImageProvider(1, 1, image: await createTestImage()).resolve(ImageConfiguration.empty)) as TestImageInfo;
    expect(a.value, equals(1));
    final TestImageInfo b = await extractOneFrame(TestImageProvider(1, 2, image: await createTestImage()).resolve(ImageConfiguration.empty)) as TestImageInfo;
    expect(b.value, equals(1));
    final TestImageInfo c = await extractOneFrame(TestImageProvider(1, 3, image: await createTestImage()).resolve(ImageConfiguration.empty)) as TestImageInfo;
    expect(c.value, equals(1));
    final TestImageInfo d = await extractOneFrame(TestImageProvider(1, 4, image: await createTestImage()).resolve(ImageConfiguration.empty)) as TestImageInfo;
    expect(d.value, equals(1));
    final TestImageInfo e = await extractOneFrame(TestImageProvider(1, 5, image: await createTestImage()).resolve(ImageConfiguration.empty)) as TestImageInfo;
    expect(e.value, equals(1));
    final TestImageInfo f = await extractOneFrame(TestImageProvider(1, 6, image: await createTestImage()).resolve(ImageConfiguration.empty)) as TestImageInfo;
    expect(f.value, equals(1));

    expect(f, equals(a));

    // cache still only has one entry in it: 1(1)

    final TestImageInfo g = await extractOneFrame(TestImageProvider(2, 7, image: await createTestImage()).resolve(ImageConfiguration.empty)) as TestImageInfo;
    expect(g.value, equals(7));

    // cache has two entries in it: 1(1), 2(7)

    final TestImageInfo h = await extractOneFrame(TestImageProvider(1, 8, image: await createTestImage()).resolve(ImageConfiguration.empty)) as TestImageInfo;
    expect(h.value, equals(1));

    // cache still has two entries in it: 2(7), 1(1)

    final TestImageInfo i = await extractOneFrame(TestImageProvider(3, 9, image: await createTestImage()).resolve(ImageConfiguration.empty)) as TestImageInfo;
    expect(i.value, equals(9));

    // cache has three entries in it: 2(7), 1(1), 3(9)

    final TestImageInfo j = await extractOneFrame(TestImageProvider(1, 10, image: await createTestImage()).resolve(ImageConfiguration.empty)) as TestImageInfo;
    expect(j.value, equals(1));

    // cache still has three entries in it: 2(7), 3(9), 1(1)

    final TestImageInfo k = await extractOneFrame(TestImageProvider(4, 11, image: await createTestImage()).resolve(ImageConfiguration.empty)) as TestImageInfo;
    expect(k.value, equals(11));

    // cache has three entries: 3(9), 1(1), 4(11)

    final TestImageInfo l = await extractOneFrame(TestImageProvider(1, 12, image: await createTestImage()).resolve(ImageConfiguration.empty)) as TestImageInfo;
    expect(l.value, equals(1));

    // cache has three entries: 3(9), 4(11), 1(1)

    final TestImageInfo m = await extractOneFrame(TestImageProvider(2, 13, image: await createTestImage()).resolve(ImageConfiguration.empty)) as TestImageInfo;
    expect(m.value, equals(13));

    // cache has three entries: 4(11), 1(1), 2(13)

    final TestImageInfo n = await extractOneFrame(TestImageProvider(3, 14, image: await createTestImage()).resolve(ImageConfiguration.empty)) as TestImageInfo;
    expect(n.value, equals(14));

    // cache has three entries: 1(1), 2(13), 3(14)

    final TestImageInfo o = await extractOneFrame(TestImageProvider(4, 15, image: await createTestImage()).resolve(ImageConfiguration.empty)) as TestImageInfo;
    expect(o.value, equals(15));

    // cache has three entries: 2(13), 3(14), 4(15)

    final TestImageInfo p = await extractOneFrame(TestImageProvider(1, 16, image: await createTestImage()).resolve(ImageConfiguration.empty)) as TestImageInfo;
    expect(p.value, equals(16));

    // cache has three entries: 3(14), 4(15), 1(16)
  });

  test('clear removes all images and resets cache size', () async {
    final ui.Image testImage = await createTestImage(width: 8, height: 8);

    expect(imageCache.currentSize, 0);
    expect(imageCache.currentSizeBytes, 0);

    await extractOneFrame(TestImageProvider(1, 1, image: testImage).resolve(ImageConfiguration.empty));
    await extractOneFrame(TestImageProvider(2, 2, image: testImage).resolve(ImageConfiguration.empty));

    expect(imageCache.currentSize, 2);
    expect(imageCache.currentSizeBytes, 256 * 2);

    imageCache.clear();

    expect(imageCache.currentSize, 0);
    expect(imageCache.currentSizeBytes, 0);
  });

  test('evicts individual images', () async {
    final ui.Image testImage = await createTestImage(width: 8, height: 8);
    await extractOneFrame(TestImageProvider(1, 1, image: testImage).resolve(ImageConfiguration.empty));
    await extractOneFrame(TestImageProvider(2, 2, image: testImage).resolve(ImageConfiguration.empty));

    expect(imageCache.currentSize, 2);
    expect(imageCache.currentSizeBytes, 256 * 2);
    expect(imageCache.evict(1), true);
    expect(imageCache.currentSize, 1);
    expect(imageCache.currentSizeBytes, 256);
  });

  test('Do not cache large images', () async {
    final ui.Image testImage = await createTestImage(width: 8, height: 8);

    imageCache.maximumSizeBytes = 1;
    await extractOneFrame(TestImageProvider(1, 1, image: testImage).resolve(ImageConfiguration.empty));
    expect(imageCache.currentSize, 0);
    expect(imageCache.currentSizeBytes, 0);
    expect(imageCache.maximumSizeBytes, 1);
  });

  test('Returns null if an error is caught resolving an image', () {
    final ErrorImageProvider errorImage = ErrorImageProvider();
    expect(() => imageCache.putIfAbsent(errorImage, () => errorImage.load(errorImage, null)), throwsA(isA<Error>()));
    bool caughtError = false;
    final ImageStreamCompleter result = imageCache.putIfAbsent(errorImage, () => errorImage.load(errorImage, null), onError: (dynamic error, StackTrace stackTrace) {
      caughtError = true;
    });
    expect(result, null);
    expect(caughtError, true);
  });

  test('already pending image is returned when it is put into the cache again', () async {
    final ui.Image testImage = await createTestImage(width: 8, height: 8);

    final TestImageStreamCompleter completer1 = TestImageStreamCompleter();
    final TestImageStreamCompleter completer2 = TestImageStreamCompleter();

    final TestImageStreamCompleter resultingCompleter1 = imageCache.putIfAbsent(testImage, () {
      return completer1;
    }) as TestImageStreamCompleter;
    final TestImageStreamCompleter resultingCompleter2 = imageCache.putIfAbsent(testImage, () {
      return completer2;
    }) as TestImageStreamCompleter;

    expect(resultingCompleter1, completer1);
    expect(resultingCompleter2, completer1);
  });

  test('pending image is removed when cache is cleared', () async {
    final ui.Image testImage = await createTestImage(width: 8, height: 8);

    final TestImageStreamCompleter completer1 = TestImageStreamCompleter();
    final TestImageStreamCompleter completer2 = TestImageStreamCompleter();

    final TestImageStreamCompleter resultingCompleter1 = imageCache.putIfAbsent(testImage, () {
      return completer1;
    }) as TestImageStreamCompleter;

    expect(imageCache.statusForKey(testImage).pending, true);
    expect(imageCache.statusForKey(testImage).live, true);
    imageCache.clear();
    expect(imageCache.statusForKey(testImage).pending, false);
    expect(imageCache.statusForKey(testImage).live, true);
    imageCache.clearLiveImages();
    expect(imageCache.statusForKey(testImage).pending, false);
    expect(imageCache.statusForKey(testImage).live, false);

    final TestImageStreamCompleter resultingCompleter2 = imageCache.putIfAbsent(testImage, () {
      return completer2;
    }) as TestImageStreamCompleter;

    expect(resultingCompleter1, completer1);
    expect(resultingCompleter2, completer2);
  });

  test('pending image is removed when image is evicted', () async {
    final ui.Image testImage = await createTestImage(width: 8, height: 8);

    final TestImageStreamCompleter completer1 = TestImageStreamCompleter();
    final TestImageStreamCompleter completer2 = TestImageStreamCompleter();

    final TestImageStreamCompleter resultingCompleter1 = imageCache.putIfAbsent(testImage, () {
      return completer1;
    }) as TestImageStreamCompleter;

    imageCache.evict(testImage);

    final TestImageStreamCompleter resultingCompleter2 = imageCache.putIfAbsent(testImage, () {
      return completer2;
    }) as TestImageStreamCompleter;

    expect(resultingCompleter1, completer1);
    expect(resultingCompleter2, completer2);
  });

  test("failed image can successfully be removed from the cache's pending images", () async {
    final ui.Image testImage = await createTestImage(width: 8, height: 8);

    FailingTestImageProvider(1, 1, image: testImage)
        .resolve(ImageConfiguration.empty)
        .addListener(ImageStreamListener(
          (ImageInfo image, bool synchronousCall) {
            fail('Image should not complete successfully');
           },
          onError: (dynamic exception, StackTrace stackTrace) {
            final bool evictionResult = imageCache.evict(1);
            expect(evictionResult, isTrue);
          },
        ));
    // yield an event turn so that async work can complete.
    await null;
  });

  test('containsKey - pending', () async {
    final ui.Image testImage = await createTestImage(width: 8, height: 8);

    final TestImageStreamCompleter completer1 = TestImageStreamCompleter();

    final TestImageStreamCompleter resultingCompleter1 = imageCache.putIfAbsent(testImage, () {
      return completer1;
    }) as TestImageStreamCompleter;

    expect(resultingCompleter1, completer1);
    expect(imageCache.containsKey(testImage), true);
  });

  test('containsKey - completed', () async {
    final ui.Image testImage = await createTestImage(width: 8, height: 8);

    final TestImageStreamCompleter completer1 = TestImageStreamCompleter();

    final TestImageStreamCompleter resultingCompleter1 = imageCache.putIfAbsent(testImage, () {
      return completer1;
    }) as TestImageStreamCompleter;

    // Mark as complete
    completer1.testSetImage(testImage);

    expect(resultingCompleter1, completer1);
    expect(imageCache.containsKey(testImage), true);
  });

  test('putIfAbsent updates LRU properties of a live image', () async {
    imageCache.maximumSize = 1;
    final ui.Image testImage = await createTestImage(width: 8, height: 8);
    final ui.Image testImage2 = await createTestImage(width: 10, height: 10);

    final TestImageStreamCompleter completer1 = TestImageStreamCompleter()..testSetImage(testImage);
    final TestImageStreamCompleter completer2 = TestImageStreamCompleter()..testSetImage(testImage2);

    completer1.addListener(ImageStreamListener((ImageInfo info, bool syncCall) {}));

    final TestImageStreamCompleter resultingCompleter1 = imageCache.putIfAbsent(testImage, () {
      return completer1;
    }) as TestImageStreamCompleter;

    expect(imageCache.statusForKey(testImage).pending, false);
    expect(imageCache.statusForKey(testImage).keepAlive, true);
    expect(imageCache.statusForKey(testImage).live, true);
    expect(imageCache.statusForKey(testImage2).untracked, true);
    final TestImageStreamCompleter resultingCompleter2 = imageCache.putIfAbsent(testImage2, () {
      return completer2;
    }) as TestImageStreamCompleter;


    expect(imageCache.statusForKey(testImage).pending, false);
    expect(imageCache.statusForKey(testImage).keepAlive, false); // evicted
    expect(imageCache.statusForKey(testImage).live, true);
    expect(imageCache.statusForKey(testImage2).pending, false);
    expect(imageCache.statusForKey(testImage2).keepAlive, true); // took the LRU spot.
    expect(imageCache.statusForKey(testImage2).live, false); // no listeners

    expect(resultingCompleter1, completer1);
    expect(resultingCompleter2, completer2);
  });

  test('Live image cache avoids leaks of unlistened streams', () async {
    imageCache.maximumSize = 3;

    TestImageProvider(1, 1, image: await createTestImage()).resolve(ImageConfiguration.empty);
    TestImageProvider(2, 2, image: await createTestImage()).resolve(ImageConfiguration.empty);
    TestImageProvider(3, 3, image: await createTestImage()).resolve(ImageConfiguration.empty);
    TestImageProvider(4, 4, image: await createTestImage()).resolve(ImageConfiguration.empty);
    TestImageProvider(5, 5, image: await createTestImage()).resolve(ImageConfiguration.empty);
    TestImageProvider(6, 6, image: await createTestImage()).resolve(ImageConfiguration.empty);

    // wait an event loop to let image resolution process.
    await null;

    expect(imageCache.currentSize, 3);
    expect(imageCache.liveImageCount, 0);
  });

  test('Disabled image cache does not leak live images', () async {
    imageCache.maximumSize = 0;

    TestImageProvider(1, 1, image: await createTestImage()).resolve(ImageConfiguration.empty);
    TestImageProvider(2, 2, image: await createTestImage()).resolve(ImageConfiguration.empty);
    TestImageProvider(3, 3, image: await createTestImage()).resolve(ImageConfiguration.empty);
    TestImageProvider(4, 4, image: await createTestImage()).resolve(ImageConfiguration.empty);
    TestImageProvider(5, 5, image: await createTestImage()).resolve(ImageConfiguration.empty);
    TestImageProvider(6, 6, image: await createTestImage()).resolve(ImageConfiguration.empty);

    // wait an event loop to let image resolution process.
    await null;

    expect(imageCache.currentSize, 0);
    expect(imageCache.liveImageCount, 0);
  });

  test('Evicting a pending image clears the live image by default', () async {
    final ui.Image testImage = await createTestImage(width: 8, height: 8);

    final TestImageStreamCompleter completer1 = TestImageStreamCompleter();

    imageCache.putIfAbsent(testImage, () => completer1);
    expect(imageCache.statusForKey(testImage).pending, true);
    expect(imageCache.statusForKey(testImage).live, true);
    expect(imageCache.statusForKey(testImage).keepAlive, false);

    imageCache.evict(testImage);
    expect(imageCache.statusForKey(testImage).untracked, true);
  });

  test('Evicting a pending image does clear the live image when includeLive is false and only cache listening', () async {
    final ui.Image testImage = await createTestImage(width: 8, height: 8);

    final TestImageStreamCompleter completer1 = TestImageStreamCompleter();

    imageCache.putIfAbsent(testImage, () => completer1);
    expect(imageCache.statusForKey(testImage).pending, true);
    expect(imageCache.statusForKey(testImage).live, true);
    expect(imageCache.statusForKey(testImage).keepAlive, false);

    imageCache.evict(testImage, includeLive: false);
    expect(imageCache.statusForKey(testImage).pending, false);
    expect(imageCache.statusForKey(testImage).live, false);
    expect(imageCache.statusForKey(testImage).keepAlive, false);
  });

  test('Evicting a pending image does clear the live image when includeLive is false and some other listener', () async {
    final ui.Image testImage = await createTestImage(width: 8, height: 8);

    final TestImageStreamCompleter completer1 = TestImageStreamCompleter();

    imageCache.putIfAbsent(testImage, () => completer1);
    expect(imageCache.statusForKey(testImage).pending, true);
    expect(imageCache.statusForKey(testImage).live, true);
    expect(imageCache.statusForKey(testImage).keepAlive, false);

    completer1.addListener(ImageStreamListener((_, __) {}));
    imageCache.evict(testImage, includeLive: false);
    expect(imageCache.statusForKey(testImage).pending, false);
    expect(imageCache.statusForKey(testImage).live, true);
    expect(imageCache.statusForKey(testImage).keepAlive, false);
  });

  test('Evicting a completed image does clear the live image by default', () async {
    final ui.Image testImage = await createTestImage(width: 8, height: 8);

    final TestImageStreamCompleter completer1 = TestImageStreamCompleter()
      ..testSetImage(testImage)
      ..addListener(ImageStreamListener((ImageInfo info, bool syncCall) {}));

    imageCache.putIfAbsent(testImage, () => completer1);
    expect(imageCache.statusForKey(testImage).pending, false);
    expect(imageCache.statusForKey(testImage).live, true);
    expect(imageCache.statusForKey(testImage).keepAlive, true);

    imageCache.evict(testImage);
    expect(imageCache.statusForKey(testImage).untracked, true);
  });

  test('Evicting a completed image does not clear the live image when includeLive is set to false', () async {
    final ui.Image testImage = await createTestImage(width: 8, height: 8);

    final TestImageStreamCompleter completer1 = TestImageStreamCompleter()
      ..testSetImage(testImage)
      ..addListener(ImageStreamListener((ImageInfo info, bool syncCall) {}));

    imageCache.putIfAbsent(testImage, () => completer1);
    expect(imageCache.statusForKey(testImage).pending, false);
    expect(imageCache.statusForKey(testImage).live, true);
    expect(imageCache.statusForKey(testImage).keepAlive, true);

    imageCache.evict(testImage, includeLive: false);
    expect(imageCache.statusForKey(testImage).pending, false);
    expect(imageCache.statusForKey(testImage).live, true);
    expect(imageCache.statusForKey(testImage).keepAlive, false);
  });

  test('Clearing liveImages removes callbacks', () async {
    final ui.Image testImage = await createTestImage(width: 8, height: 8);

    final ImageStreamListener listener = ImageStreamListener((ImageInfo info, bool syncCall) {});

    final TestImageStreamCompleter completer1 = TestImageStreamCompleter()
      ..testSetImage(testImage)
      ..addListener(listener);

    final TestImageStreamCompleter completer2 = TestImageStreamCompleter()
      ..testSetImage(testImage)
      ..addListener(listener);

    imageCache.putIfAbsent(testImage, () => completer1);
    expect(imageCache.statusForKey(testImage).pending, false);
    expect(imageCache.statusForKey(testImage).live, true);
    expect(imageCache.statusForKey(testImage).keepAlive, true);

    imageCache.clear();
    imageCache.clearLiveImages();
    expect(imageCache.statusForKey(testImage).pending, false);
    expect(imageCache.statusForKey(testImage).live, false);
    expect(imageCache.statusForKey(testImage).keepAlive, false);

    imageCache.putIfAbsent(testImage, () => completer2);
    expect(imageCache.statusForKey(testImage).pending, false);
    expect(imageCache.statusForKey(testImage).live, true);
    expect(imageCache.statusForKey(testImage).keepAlive, true);

    completer1.removeListener(listener);

    expect(imageCache.statusForKey(testImage).pending, false);
    expect(imageCache.statusForKey(testImage).live, true);
    expect(imageCache.statusForKey(testImage).keepAlive, true);
  });

  test('Live image gets size updated', () async {
    // Add an image to the cache in pending state
    // Complete it once it is in there as live
    // Evict it but leave the live one.
    // Add it again.
    // If the live image did not track the size properly, the last line of
    // this test will fail.

    final ui.Image testImage = await createTestImage(width: 8, height: 8);
    const int testImageSize = 8 * 8 * 4;

    final ImageStreamListener listener = ImageStreamListener((ImageInfo info, bool syncCall) {});

    final TestImageStreamCompleter completer1 = TestImageStreamCompleter()
      ..addListener(listener);


    imageCache.putIfAbsent(testImage, () => completer1);
    expect(imageCache.statusForKey(testImage).pending, true);
    expect(imageCache.statusForKey(testImage).live, true);
    expect(imageCache.statusForKey(testImage).keepAlive, false);
    expect(imageCache.currentSizeBytes, 0);

    completer1.testSetImage(testImage);

    expect(imageCache.statusForKey(testImage).pending, false);
    expect(imageCache.statusForKey(testImage).live, true);
    expect(imageCache.statusForKey(testImage).keepAlive, true);
    expect(imageCache.currentSizeBytes, testImageSize);

    imageCache.evict(testImage, includeLive: false);

    expect(imageCache.statusForKey(testImage).pending, false);
    expect(imageCache.statusForKey(testImage).live, true);
    expect(imageCache.statusForKey(testImage).keepAlive, false);
    expect(imageCache.currentSizeBytes, 0);

    imageCache.putIfAbsent(testImage, () => completer1);

    expect(imageCache.statusForKey(testImage).pending, false);
    expect(imageCache.statusForKey(testImage).live, true);
    expect(imageCache.statusForKey(testImage).keepAlive, true);
    expect(imageCache.currentSizeBytes, testImageSize);
  });
}