Merge "Add Binder support for Parcelable exceptions."

am: a2ef6b5741

Change-Id: Ide766c0220e86b7661af83551354b3a498297ed8

core/java/android/os/Parcel.java

@@ -27,6 +27,8 @@ import android.util.SizeF;
 import android.util.SparseArray;
 import android.util.SparseBooleanArray;
 
+import libcore.util.SneakyThrow;
+
 import java.io.ByteArrayInputStream;
 import java.io.ByteArrayOutputStream;
 import java.io.FileDescriptor;
@@ -249,6 +251,7 @@ public final class Parcel {
     private static final int EX_NETWORK_MAIN_THREAD = -6;
     private static final int EX_UNSUPPORTED_OPERATION = -7;
     private static final int EX_SERVICE_SPECIFIC = -8;
+    private static final int EX_PARCELABLE = -9;
     private static final int EX_HAS_REPLY_HEADER = -128;  // special; see below
     // EX_TRANSACTION_FAILED is used exclusively in native code.
     // see libbinder's binder/Status.h
@@ -1555,7 +1558,12 @@ public final class Parcel {
      */
     public final void writeException(Exception e) {
         int code = 0;
-        if (e instanceof SecurityException) {
+        if (e instanceof Parcelable
+                && (e.getClass().getClassLoader() == Parcelable.class.getClassLoader())) {
+            // We only send Parcelable exceptions that are in the
+            // BootClassLoader to ensure that the receiver can unpack them
+            code = EX_PARCELABLE;
+        } else if (e instanceof SecurityException) {
             code = EX_SECURITY;
         } else if (e instanceof BadParcelableException) {
             code = EX_BAD_PARCELABLE;
@@ -1581,8 +1589,20 @@ public final class Parcel {
             throw new RuntimeException(e);
         }
         writeString(e.getMessage());
-        if (e instanceof ServiceSpecificException) {
-            writeInt(((ServiceSpecificException)e).errorCode);
+        switch (code) {
+            case EX_SERVICE_SPECIFIC:
+                writeInt(((ServiceSpecificException) e).errorCode);
+                break;
+            case EX_PARCELABLE:
+                // Write parceled exception prefixed by length
+                final int sizePosition = dataPosition();
+                writeInt(0);
+                writeParcelable((Parcelable) e, Parcelable.PARCELABLE_WRITE_RETURN_VALUE);
+                final int payloadPosition = dataPosition();
+                setDataPosition(sizePosition);
+                writeInt(payloadPosition - sizePosition);
+                setDataPosition(payloadPosition);
+                break;
         }
     }
 
@@ -1680,6 +1700,13 @@ public final class Parcel {
      */
     public final void readException(int code, String msg) {
         switch (code) {
+            case EX_PARCELABLE:
+                if (readInt() > 0) {
+                    SneakyThrow.sneakyThrow(
+                            (Exception) readParcelable(Parcelable.class.getClassLoader()));
+                } else {
+                    throw new RuntimeException(msg + " [missing Parcelable]");
+                }
             case EX_SECURITY:
                 throw new SecurityException(msg);
             case EX_BAD_PARCELABLE:

core/java/android/os/ParcelableException.java

@@ -0,0 +1,88 @@
+/*
+ * Copyright (C) 2017 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package android.os;
+
+import java.io.IOException;
+
+/**
+ * Wrapper class that offers to transport typical {@link Throwable} across a
+ * {@link Binder} call. This class is typically used to transport exceptions
+ * that cannot be modified to add {@link Parcelable} behavior, such as
+ * {@link IOException}.
+ * <ul>
+ * <li>The wrapped throwable must be defined as system class (that is, it must
+ * be in the same {@link ClassLoader} as {@link Parcelable}).
+ * <li>The wrapped throwable must support the
+ * {@link Throwable#Throwable(String)} constructor.
+ * <li>The receiver side must catch any thrown {@link ParcelableException} and
+ * call {@link #maybeRethrow(Class)} for all expected exception types.
+ * </ul>
+ *
+ * @hide
+ */
+public final class ParcelableException extends RuntimeException implements Parcelable {
+    public ParcelableException(Throwable t) {
+        super(t);
+    }
+
+    @SuppressWarnings("unchecked")
+    public <T extends Throwable> void maybeRethrow(Class<T> clazz) throws T {
+        if (clazz.isAssignableFrom(getCause().getClass())) {
+            throw (T) getCause();
+        }
+    }
+
+    /** {@hide} */
+    public static Throwable readFromParcel(Parcel in) {
+        final String name = in.readString();
+        final String msg = in.readString();
+        try {
+            final Class<?> clazz = Class.forName(name, true, Parcelable.class.getClassLoader());
+            return (Throwable) clazz.getConstructor(String.class).newInstance(msg);
+        } catch (ReflectiveOperationException e) {
+            throw new RuntimeException(name + ": " + msg);
+        }
+    }
+
+    /** {@hide} */
+    public static void writeToParcel(Parcel out, Throwable t) {
+        out.writeString(t.getClass().getName());
+        out.writeString(t.getMessage());
+    }
+
+    @Override
+    public int describeContents() {
+        return 0;
+    }
+
+    @Override
+    public void writeToParcel(Parcel dest, int flags) {
+        writeToParcel(dest, getCause());
+    }
+
+    public static final Creator<ParcelableException> CREATOR = new Creator<ParcelableException>() {
+        @Override
+        public ParcelableException createFromParcel(Parcel source) {
+            return new ParcelableException(readFromParcel(source));
+        }
+
+        @Override
+        public ParcelableException[] newArray(int size) {
+            return new ParcelableException[size];
+        }
+    };
+}

core/java/android/util/ExceptionUtils.java

@@ -16,6 +16,8 @@
 
 package android.util;
 
+import android.os.ParcelableException;
+
 import java.io.IOException;
 
 /**
@@ -24,19 +26,13 @@ import java.io.IOException;
  * @hide
  */
 public class ExceptionUtils {
-    // TODO: longer term these should be replaced with first-class
-    // Parcel.read/writeException() and AIDL support, but for now do this using
-    // a nasty hack.
-
-    private static final String PREFIX_IO = "\u2603";
-
     public static RuntimeException wrap(IOException e) {
-        throw new IllegalStateException(PREFIX_IO + e.getMessage());
+        throw new ParcelableException(e);
     }
 
     public static void maybeUnwrapIOException(RuntimeException e) throws IOException {
-        if ((e instanceof IllegalStateException) && e.getMessage().startsWith(PREFIX_IO)) {
-            throw new IOException(e.getMessage().substring(PREFIX_IO.length()));
+        if (e instanceof ParcelableException) {
+            ((ParcelableException) e).maybeRethrow(IOException.class);
         }
     }