Show download progress. Caching of images now without glide

app/src/main/java/eu/kanade/mangafeed/data/helpers/NetworkHelper.java

@@ -3,15 +3,24 @@ package eu.kanade.mangafeed.data.helpers;
 
 import com.squareup.okhttp.CacheControl;
 import com.squareup.okhttp.Headers;
+import com.squareup.okhttp.MediaType;
 import com.squareup.okhttp.OkHttpClient;
 import com.squareup.okhttp.Request;
 import com.squareup.okhttp.RequestBody;
 import com.squareup.okhttp.Response;
+import com.squareup.okhttp.ResponseBody;
 
+import java.io.IOException;
 import java.net.CookieManager;
 import java.net.CookiePolicy;
 import java.net.CookieStore;
 
+import eu.kanade.mangafeed.data.models.Page;
+import okio.Buffer;
+import okio.BufferedSource;
+import okio.ForwardingSource;
+import okio.Okio;
+import okio.Source;
 import rx.Observable;
 
 public final class NetworkHelper {
@@ -82,8 +91,79 @@ public final class NetworkHelper {
         });
     }
 
+    public Observable<Response> getProgressResponse(final String url, final Headers headers, final Page page) {
+        return Observable.<Response>create(subscriber -> {
+            try {
+                if (!subscriber.isUnsubscribed()) {
+                    Request request = new Request.Builder()
+                            .url(url)
+                            .cacheControl(NULL_CACHE_CONTROL)
+                            .headers(headers != null ? headers : NULL_HEADERS)
+                            .build();
+
+                    OkHttpClient progressClient = mClient.clone();
+
+                    progressClient.networkInterceptors().add(chain -> {
+                        Response originalResponse = chain.proceed(chain.request());
+                        return originalResponse.newBuilder()
+                                .body(new ProgressResponseBody(originalResponse.body(), page))
+                                .build();
+                    });
+                    subscriber.onNext(progressClient.newCall(request).execute());
+                }
+                subscriber.onCompleted();
+            } catch (Throwable e) {
+                subscriber.onError(e);
+            }
+        }).retry(3);
+    }
+
     public CookieStore getCookies() {
         return cookieManager.getCookieStore();
     }
 
+    private static class ProgressResponseBody extends ResponseBody {
+
+        private final ResponseBody responseBody;
+        private final ProgressListener progressListener;
+        private BufferedSource bufferedSource;
+
+        public ProgressResponseBody(ResponseBody responseBody, ProgressListener progressListener) {
+            this.responseBody = responseBody;
+            this.progressListener = progressListener;
+        }
+
+        @Override public MediaType contentType() {
+            return responseBody.contentType();
+        }
+
+        @Override public long contentLength() throws IOException {
+            return responseBody.contentLength();
+        }
+
+        @Override public BufferedSource source() throws IOException {
+            if (bufferedSource == null) {
+                bufferedSource = Okio.buffer(source(responseBody.source()));
+            }
+            return bufferedSource;
+        }
+
+        private Source source(Source source) {
+            return new ForwardingSource(source) {
+                long totalBytesRead = 0L;
+                @Override public long read(Buffer sink, long byteCount) throws IOException {
+                    long bytesRead = super.read(sink, byteCount);
+                    // read() returns the number of bytes read, or -1 if this source is exhausted.
+                    totalBytesRead += bytesRead != -1 ? bytesRead : 0;
+                    progressListener.update(totalBytesRead, responseBody.contentLength(), bytesRead == -1);
+                    return bytesRead;
+                }
+            };
+        }
+    }
+
+    public interface ProgressListener {
+        void update(long bytesRead, long contentLength, boolean done);
+    }
+
 }