From 69c889815e7dfede6503be7cb20c6515f503116e Mon Sep 17 00:00:00 2001
From: Felix Oghina <foghina@fb.com>
Date: Wed, 31 Aug 2016 05:06:10 -0700
Subject: [PATCH] Expose image cache interrogation to JS

Summary: Add a static `Image.queryCache` function that can query multiple URLs at once. The result is a map where each URL that is in cache is mapped to the cache type (memory/disk). URLs that are not cached do not appear in the result.

Reviewed By: lexs

Differential Revision: D3791333

fbshipit-source-id: b183015d97423f0c095bf891f035dac2e23d8d11
---
 Libraries/Image/Image.android.js              | 11 ++++++++
 .../modules/image/ImageLoaderModule.java      | 25 +++++++++++++++++++
 2 files changed, 36 insertions(+)

diff --git a/Libraries/Image/Image.android.js b/Libraries/Image/Image.android.js
index ae2c8d5ef92..4eff9533efd 100644
--- a/Libraries/Image/Image.android.js
+++ b/Libraries/Image/Image.android.js
@@ -185,6 +185,17 @@ var Image = React.createClass({
     abortPrefetch(requestId: number) {
       ImageLoader.abortRequest(requestId);
     },
+
+    /**
+     * Perform cache interrogation.
+     *
+     * @param urls the list of image URLs to check the cache for.
+     * @return a mapping from url to cache status, such as "disk" or "memory". If a requested URL is
+     *         not in the mapping, it means it's not in the cache.
+     */
+    async queryCache(urls: Array<string>): Promise<Map<string, 'memory' | 'disk'>> {
+      return await ImageLoader.queryCache(urls);
+    }
   },
 
   mixins: [NativeMethodsMixin],
diff --git a/ReactAndroid/src/main/java/com/facebook/react/modules/image/ImageLoaderModule.java b/ReactAndroid/src/main/java/com/facebook/react/modules/image/ImageLoaderModule.java
index 54730146d2d..b717969e187 100644
--- a/ReactAndroid/src/main/java/com/facebook/react/modules/image/ImageLoaderModule.java
+++ b/ReactAndroid/src/main/java/com/facebook/react/modules/image/ImageLoaderModule.java
@@ -20,15 +20,18 @@ import com.facebook.datasource.BaseDataSubscriber;
 import com.facebook.datasource.DataSource;
 import com.facebook.datasource.DataSubscriber;
 import com.facebook.drawee.backends.pipeline.Fresco;
+import com.facebook.imagepipeline.core.ImagePipeline;
 import com.facebook.imagepipeline.image.CloseableImage;
 import com.facebook.imagepipeline.request.ImageRequest;
 import com.facebook.imagepipeline.request.ImageRequestBuilder;
 import com.facebook.react.bridge.Arguments;
+import com.facebook.react.bridge.GuardedAsyncTask;
 import com.facebook.react.bridge.LifecycleEventListener;
 import com.facebook.react.bridge.Promise;
 import com.facebook.react.bridge.ReactApplicationContext;
 import com.facebook.react.bridge.ReactContextBaseJavaModule;
 import com.facebook.react.bridge.ReactMethod;
+import com.facebook.react.bridge.ReadableArray;
 import com.facebook.react.bridge.WritableMap;
 
 public class ImageLoaderModule extends ReactContextBaseJavaModule implements
@@ -175,6 +178,28 @@ public class ImageLoaderModule extends ReactContextBaseJavaModule implements
     }
   }
 
+  @ReactMethod
+  public void queryCache(final ReadableArray uris, final Promise promise) {
+    // perform cache interrogation in async task as disk cache checks are expensive
+    new GuardedAsyncTask<Void, Void>(getReactApplicationContext()) {
+      @Override
+      protected void doInBackgroundGuarded(Void... params) {
+        WritableMap result = Arguments.createMap();
+        ImagePipeline imagePipeline = Fresco.getImagePipeline();
+        for (int i = 0; i < uris.size(); i++) {
+          String uriString = uris.getString(i);
+          final Uri uri = Uri.parse(uriString);
+          if (imagePipeline.isInBitmapMemoryCache(uri)) {
+            result.putString(uriString, "memory");
+          } else if (imagePipeline.isInDiskCacheSync(uri)) {
+            result.putString(uriString, "disk");
+          }
+        }
+        promise.resolve(result);
+      }
+    }.executeOnExecutor(GuardedAsyncTask.THREAD_POOL_EXECUTOR);
+  }
+
   private void registerRequest(int requestId, DataSource<Void> request) {
     synchronized (mEnqueuedRequestMonitor) {
       mEnqueuedRequests.put(requestId, request);