make DownloadRequest ArrayList parcelable (support a batch of them)

core/src/androidTest/java/de/danoeh/antennapod/core/service/download/DownloadRequestTest.java

@@ -0,0 +1,122 @@
+package de.danoeh.antennapod.core.service.download;
+
+import android.os.Bundle;
+import android.os.Parcel;
+
+import androidx.test.filters.SmallTest;
+
+import org.junit.Test;
+
+import java.util.ArrayList;
+
+import de.danoeh.antennapod.core.feed.FeedFile;
+
+import static org.junit.Assert.assertEquals;
+
+@SmallTest
+public class DownloadRequestTest {
+
+    @Test
+    public void parcelInArrayListTest_WithAuth() {
+        doTestParcelInArrayList("case has authentication",
+                "usr1", "pass1", "usr2", "pass2");
+    }
+
+    @Test
+    public void parcelInArrayListTest_NoAuth() {
+        doTestParcelInArrayList("case no authentication",
+                null, null, null, null);
+    }
+
+    @Test
+    public void parcelInArrayListTest_MixAuth() {
+        doTestParcelInArrayList("case mixed authentication",
+                null, null, "usr2", "pass2");
+    }
+
+    // Test to ensure parcel using put/getParcelableArrayList() API work
+    // based on: https://stackoverflow.com/a/13507191
+    private void doTestParcelInArrayList(String message,
+                                         String username1, String password1,
+                                         String username2, String password2) {
+        ArrayList<DownloadRequest> toParcel;
+        { // test DownloadRequests to parcel
+            String destStr = "file://location/media.mp3";
+            FeedFile item1 = createFeedItem(1);
+            Bundle arg1 = new Bundle();
+            arg1.putString("arg1", "value1");
+            DownloadRequest request1 = new DownloadRequest.Builder(destStr, item1)
+                    .withAuthentication(username1, password1)
+                    .withArguments(arg1)
+                    .build();
+
+            FeedFile item2 = createFeedItem(2);
+            DownloadRequest request2 = new DownloadRequest.Builder(destStr, item2)
+                    .withAuthentication(username2, password2)
+                    .build();
+
+            toParcel = new ArrayList<>();
+            toParcel.add(request1);
+            toParcel.add(request2);
+        }
+
+        // parcel the download requests
+        Bundle bundleIn = new Bundle();
+        bundleIn.putParcelableArrayList("r", toParcel);
+
+        Parcel parcel = Parcel.obtain();
+        bundleIn.writeToParcel(parcel, 0);
+
+        Bundle bundleOut = new Bundle();
+        bundleOut.setClassLoader(DownloadRequest.class.getClassLoader());
+        parcel.setDataPosition(0); // to read the parcel from the beginning.
+        bundleOut.readFromParcel(parcel);
+
+        ArrayList<DownloadRequest> fromParcel = bundleOut.getParcelableArrayList("r");
+
+        // spot-check contents to ensure they are the same
+        // DownloadRequest.equals() implementation doesn't quite work
+        // for DownloadRequest.argument (a Bundle)
+        assertEquals(message + " - size", toParcel.size(), fromParcel.size());
+        assertEquals(message + " - source", toParcel.get(1).getSource(), fromParcel.get(1).getSource());
+        assertEquals(message + " - password", toParcel.get(0).getPassword(), fromParcel.get(0).getPassword());
+        assertEquals(message + " - argument", toString(toParcel.get(0).getArguments()),
+                toString(fromParcel.get(0).getArguments()));
+    }
+
+    private static String toString(Bundle b) {
+        StringBuilder sb = new StringBuilder();
+        sb.append("{");
+        for (String key: b.keySet()) {
+            Object val = b.get(key);
+            sb.append("(").append(key).append(":").append(val).append(") ");
+        }
+        sb.append("}");
+        return sb.toString();
+    }
+
+    private FeedFile createFeedItem(final int id) {
+        // Use mockito would be less verbose, but it'll take extra 1 second for this tiny test
+        return new FeedFile() {
+            @Override
+            public long getId() {
+                return id;
+            }
+
+            @Override
+            public String getDownload_url() {
+                return "http://example.com/episode" + id;
+            }
+
+            @Override
+            public int getTypeAsInt() {
+                return 0;
+            }
+
+            @Override
+            public String getHumanReadableIdentifier() {
+                return "human-id-" + id;
+            }
+        };
+    }
+}

core/src/main/java/de/danoeh/antennapod/core/service/download/DownloadRequest.java

@@ -3,6 +3,8 @@ package de.danoeh.antennapod.core.service.download;
 import android.os.Bundle;
 import android.os.Parcel;
 import android.os.Parcelable;
+import android.text.TextUtils;
+
 import androidx.annotation.NonNull;
 import androidx.annotation.Nullable;
 
@@ -74,17 +76,9 @@ public class DownloadRequest implements Parcelable {
         feedfileType = in.readInt();
         lastModified = in.readString();
         deleteOnFailure = (in.readByte() > 0);
+        username = nullIfEmpty(in.readString());
+        password = nullIfEmpty(in.readString());
         arguments = in.readBundle();
-        if (in.dataAvail() > 0) {
-            username = in.readString();
-        } else {
-            username = null;
-        }
-        if (in.dataAvail() > 0) {
-            password = in.readString();
-        } else {
-            password = null;
-        }
     }
 
     @Override
@@ -101,13 +95,22 @@ public class DownloadRequest implements Parcelable {
         dest.writeInt(feedfileType);
         dest.writeString(lastModified);
         dest.writeByte((deleteOnFailure) ? (byte) 1 : 0);
+        // in case of null username/password, still write an empty string
+        // (rather than skipping it). Otherwise, unmarshalling  a collection
+        // of them from a Parcel (from an Intent extra to submit a request to DownloadService) will fail.
+        //
+        // see: https://stackoverflow.com/a/22926342
+        dest.writeString(nonNullString(username));
+        dest.writeString(nonNullString(password));
         dest.writeBundle(arguments);
-        if (username != null) {
-            dest.writeString(username);
-        }
-        if (password != null) {
-            dest.writeString(password);
-        }
+    }
+
+    private static String nonNullString(String str) {
+        return str != null ? str : "";
+    }
+
+    private static String nullIfEmpty(String str) {
+        return TextUtils.isEmpty(str) ? null : str;
     }
 
     public static final Parcelable.Creator<DownloadRequest> CREATOR = new Parcelable.Creator<DownloadRequest>() {