chrome/android/java/src/org/chromium/chrome/browser/image_fetcher/ImageFetcherFactory.java

// Copyright 2019 The Chromium Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

package org.chromium.chrome.browser.image_fetcher;

import org.chromium.base.DiscardableReferencePool;

/**
 * Factory to provide the image fetcher best suited for the given config.
 */
public class ImageFetcherFactory {
    // Store static references to singleton image fetchers.
    private static CachedImageFetcher sCachedImageFetcher;
    private static NetworkImageFetcher sNetworkImageFetcher;

    /**
     * Alias for createImageFetcher below.
     */
    public static ImageFetcher createImageFetcher(@ImageFetcherConfig int config) {
        return createImageFetcher(config, ImageFetcherBridge.getInstance(), null,
                InMemoryCachedImageFetcher.DEFAULT_CACHE_SIZE);
    }

    /**
     * Alias for createImageFetcher below.
     */
    public static ImageFetcher createImageFetcher(
            @ImageFetcherConfig int config, DiscardableReferencePool discardableReferencePool) {
        return createImageFetcher(config, ImageFetcherBridge.getInstance(),
                discardableReferencePool, InMemoryCachedImageFetcher.DEFAULT_CACHE_SIZE);
    }

    /**
     * Alias for createImageFetcher below.
     */
    public static ImageFetcher createImageFetcher(@ImageFetcherConfig int config,
            DiscardableReferencePool discardableReferencePool, int inMemoryCacheSize) {
        return createImageFetcher(config, ImageFetcherBridge.getInstance(),
                discardableReferencePool, inMemoryCacheSize);
    }

    /**
     * Return the image fetcher that matches the given config. This will return an image fetcher
     * config that you must destroy.
     *
     * @param config The type of ImageFetcher you need.
     * @param imageFetcherBridge Bridge to use.
     * @param discardableReferencePool Used to store images in-memory.
     * @param inMemoryCacheSize The size of the in memory cache (in bytes).
     * @return The correct ImageFetcher according to the provided config.
     */
    public static ImageFetcher createImageFetcher(@ImageFetcherConfig int config,
            ImageFetcherBridge imageFetcherBridge,
            DiscardableReferencePool discardableReferencePool, int inMemoryCacheSize) {
        // TODO(crbug.com/947191):Allow server-side configuration image fetcher clients.
        switch (config) {
            case ImageFetcherConfig.NETWORK_ONLY:
                if (sNetworkImageFetcher == null) {
                    sNetworkImageFetcher = new NetworkImageFetcher(imageFetcherBridge);
                }
                return sNetworkImageFetcher;
            case ImageFetcherConfig.DISK_CACHE_ONLY:
                if (sCachedImageFetcher == null) {
                    sCachedImageFetcher = new CachedImageFetcher(imageFetcherBridge);
                }
                return sCachedImageFetcher;
            case ImageFetcherConfig.IN_MEMORY_ONLY:
                assert discardableReferencePool != null;
                return new InMemoryCachedImageFetcher(
                        createImageFetcher(ImageFetcherConfig.NETWORK_ONLY, imageFetcherBridge,
                                discardableReferencePool, inMemoryCacheSize),
                        discardableReferencePool, inMemoryCacheSize);
            case ImageFetcherConfig.IN_MEMORY_WITH_DISK_CACHE:
                assert discardableReferencePool != null;
                return new InMemoryCachedImageFetcher(
                        createImageFetcher(ImageFetcherConfig.DISK_CACHE_ONLY, imageFetcherBridge,
                                discardableReferencePool, inMemoryCacheSize),
                        discardableReferencePool, inMemoryCacheSize);
            default:
                return null;
        }
    }
}