Improve @hide Parcel.hasFileDescriptors(Object)

Addressing Jeff's comment on aosp/1787847 to support List<> in
Parcel.hasFileDescriptor(), also added support for Map (+ArrayMap) and
Object[] that were missing. Made the checks recursive since it's
possible to put nested containers in bundle. Since that's @hide and only
used by bundle, included Parcel as a supported type too and clarified in
the javadoc.

That allowed to clean up Bundle.hasFileDescriptors().

Bug: 195622897
Test: atest -d android.os.cts.ParcelTest android.os.cts.BundleTest android.os.BundleTest android.os.ParcelTest
Change-Id: I6acf358763d8f544fc6ff1a5b0c8bdff567d50be
diff --git a/core/java/android/os/Bundle.java b/core/java/android/os/Bundle.java
index 92eb7a5..feca81e 100644
--- a/core/java/android/os/Bundle.java
+++ b/core/java/android/os/Bundle.java
@@ -324,28 +324,10 @@
      */
     public boolean hasFileDescriptors() {
         if ((mFlags & FLAG_HAS_FDS_KNOWN) == 0) {
-            boolean fdFound = false;    // keep going until we find one or run out of data
-
-            if (mParcelledData != null) {
-                if (mParcelledData.hasFileDescriptors()) {
-                    fdFound = true;
-                }
-            } else {
-                // It's been unparcelled, so we need to walk the map
-                for (int i=mMap.size()-1; i>=0; i--) {
-                    Object obj = mMap.valueAt(i);
-                    if (Parcel.hasFileDescriptors(obj)) {
-                        fdFound = true;
-                        break;
-                    }
-                }
-            }
-
-            if (fdFound) {
-                mFlags |= FLAG_HAS_FDS;
-            } else {
-                mFlags &= ~FLAG_HAS_FDS;
-            }
+            Parcel p = mParcelledData;
+            mFlags = (Parcel.hasFileDescriptors((p != null) ? p : mMap))
+                    ? mFlags | FLAG_HAS_FDS
+                    : mFlags & ~FLAG_HAS_FDS;
             mFlags |= FLAG_HAS_FDS_KNOWN;
         }
         return (mFlags & FLAG_HAS_FDS) != 0;
diff --git a/core/java/android/os/Parcel.java b/core/java/android/os/Parcel.java
index 61882ff..623c03d 100644
--- a/core/java/android/os/Parcel.java
+++ b/core/java/android/os/Parcel.java
@@ -747,57 +747,70 @@
     }
 
     /**
-     * Check if the object used in {@link #readValue(ClassLoader)} / {@link #writeValue(Object)}
-     * has file descriptors.
+     * Check if the object has file descriptors.
+     *
+     * <p>Objects supported are {@link Parcel} and objects that can be passed to {@link
+     * #writeValue(Object)}}
      *
      * <p>For most cases, it will use the self-reported {@link Parcelable#describeContents()} method
      * for that.
      *
-     * @throws IllegalArgumentException if you provide any object not supported by above methods.
-     *         Most notably, if you pass {@link Parcel}, this method will throw, for that check
-     *         {@link Parcel#hasFileDescriptors()}
+     * @throws IllegalArgumentException if you provide any object not supported by above methods
+     *     (including if the unsupported object is inside a nested container).
      *
      * @hide
      */
     public static boolean hasFileDescriptors(Object value) {
-        if (value instanceof LazyValue) {
-            return ((LazyValue) value).hasFileDescriptors();
-        } else if (value instanceof Parcelable) {
-            if ((((Parcelable) value).describeContents()
-                    & Parcelable.CONTENTS_FILE_DESCRIPTOR) != 0) {
+        if (value instanceof Parcel) {
+            Parcel parcel = (Parcel) value;
+            if (parcel.hasFileDescriptors()) {
                 return true;
             }
-        } else if (value instanceof Parcelable[]) {
-            Parcelable[] array = (Parcelable[]) value;
-            for (int n = array.length - 1; n >= 0; n--) {
-                Parcelable p = array[n];
-                if (p != null && ((p.describeContents()
-                        & Parcelable.CONTENTS_FILE_DESCRIPTOR) != 0)) {
+        } else if (value instanceof LazyValue) {
+            LazyValue lazy = (LazyValue) value;
+            if (lazy.hasFileDescriptors()) {
+                return true;
+            }
+        } else if (value instanceof Parcelable) {
+            Parcelable parcelable = (Parcelable) value;
+            if ((parcelable.describeContents() & Parcelable.CONTENTS_FILE_DESCRIPTOR) != 0) {
+                return true;
+            }
+        } else if (value instanceof ArrayMap<?, ?>) {
+            ArrayMap<?, ?> map = (ArrayMap<?, ?>) value;
+            for (int i = 0, n = map.size(); i < n; i++) {
+                if (hasFileDescriptors(map.keyAt(i))
+                        || hasFileDescriptors(map.valueAt(i))) {
+                    return true;
+                }
+            }
+        } else if (value instanceof Map<?, ?>) {
+            Map<?, ?> map = (Map<?, ?>) value;
+            for (Map.Entry<?, ?> entry : map.entrySet()) {
+                if (hasFileDescriptors(entry.getKey())
+                        || hasFileDescriptors(entry.getValue())) {
+                    return true;
+                }
+            }
+        } else if (value instanceof List<?>) {
+            List<?> list = (List<?>) value;
+            for (int i = 0, n = list.size(); i < n; i++) {
+                if (hasFileDescriptors(list.get(i))) {
                     return true;
                 }
             }
         } else if (value instanceof SparseArray<?>) {
             SparseArray<?> array = (SparseArray<?>) value;
-            for (int n = array.size() - 1; n >= 0; n--) {
-                Object object = array.valueAt(n);
-                if (object instanceof Parcelable) {
-                    Parcelable p = (Parcelable) object;
-                    if (p != null && (p.describeContents()
-                            & Parcelable.CONTENTS_FILE_DESCRIPTOR) != 0) {
-                        return true;
-                    }
+            for (int i = 0, n = array.size(); i < n; i++) {
+                if (hasFileDescriptors(array.valueAt(i))) {
+                    return true;
                 }
             }
-        } else if (value instanceof ArrayList<?>) {
-            ArrayList<?> array = (ArrayList<?>) value;
-            for (int n = array.size() - 1; n >= 0; n--) {
-                Object object = array.get(n);
-                if (object instanceof Parcelable) {
-                    Parcelable p = (Parcelable) object;
-                    if (p != null && ((p.describeContents()
-                            & Parcelable.CONTENTS_FILE_DESCRIPTOR) != 0)) {
-                        return true;
-                    }
+        } else if (value instanceof Object[]) {
+            Object[] array = (Object[]) value;
+            for (int i = 0, n = array.length; i < n; i++) {
+                if (hasFileDescriptors(array[i])) {
+                    return true;
                 }
             }
         } else {