Detect invalid uses of Message.
Throw an exception when an application attempts to recycle or
resend messages that are still in-use.
Change-Id: I7096e8b7bd5bec41b7b8ef0c798c55ce3db6827e
diff --git a/core/java/android/os/Looper.java b/core/java/android/os/Looper.java
index ff31130..6d7c9cf 100644
--- a/core/java/android/os/Looper.java
+++ b/core/java/android/os/Looper.java
@@ -149,7 +149,7 @@
+ msg.callback + " what=" + msg.what);
}
- msg.recycle();
+ msg.recycleUnchecked();
}
}
diff --git a/core/java/android/os/Message.java b/core/java/android/os/Message.java
index 51203a48..d30bbc1 100644
--- a/core/java/android/os/Message.java
+++ b/core/java/android/os/Message.java
@@ -71,7 +71,14 @@
*/
public Messenger replyTo;
- /** If set message is in use */
+ /** If set message is in use.
+ * This flag is set when the message is enqueued and remains set while it
+ * is delivered and afterwards when it is recycled. The flag is only cleared
+ * when a new message is created or obtained since that is the only time that
+ * applications are allowed to modify the contents of the message.
+ *
+ * It is an error to attempt to enqueue or recycle a message that is already in use.
+ */
/*package*/ static final int FLAG_IN_USE = 1 << 0;
/** If set message is asynchronous */
@@ -86,9 +93,9 @@
/*package*/ Bundle data;
- /*package*/ Handler target;
+ /*package*/ Handler target;
- /*package*/ Runnable callback;
+ /*package*/ Runnable callback;
// sometimes we store linked lists of these things
/*package*/ Message next;
@@ -109,6 +116,7 @@
Message m = sPool;
sPool = m.next;
m.next = null;
+ m.flags = 0; // clear in-use flag
sPoolSize--;
return m;
}
@@ -241,12 +249,38 @@
}
/**
- * Return a Message instance to the global pool. You MUST NOT touch
- * the Message after calling this function -- it has effectively been
- * freed.
+ * Return a Message instance to the global pool.
+ * <p>
+ * You MUST NOT touch the Message after calling this function because it has
+ * effectively been freed. It is an error to recycle a message that is currently
+ * enqueued or that is in the process of being delivered to a Handler.
+ * </p>
*/
public void recycle() {
- clearForRecycle();
+ if (isInUse()) {
+ throw new IllegalStateException("This message cannot be recycled because it "
+ + "is still in use.");
+ }
+ recycleUnchecked();
+ }
+
+ /**
+ * Recycles a Message that may be in-use.
+ * Used internally by the MessageQueue and Looper when disposing of queued Messages.
+ */
+ void recycleUnchecked() {
+ // Mark the message as in use while it remains in the recycled object pool.
+ // Clear out all other details.
+ flags = FLAG_IN_USE;
+ what = 0;
+ arg1 = 0;
+ arg2 = 0;
+ obj = null;
+ replyTo = null;
+ when = 0;
+ target = null;
+ callback = null;
+ data = null;
synchronized (sPoolSync) {
if (sPoolSize < MAX_POOL_SIZE) {
@@ -402,19 +436,6 @@
}
}
- /*package*/ void clearForRecycle() {
- flags = 0;
- what = 0;
- arg1 = 0;
- arg2 = 0;
- obj = null;
- replyTo = null;
- when = 0;
- target = null;
- callback = null;
- data = null;
- }
-
/*package*/ boolean isInUse() {
return ((flags & FLAG_IN_USE) == FLAG_IN_USE);
}
diff --git a/core/java/android/os/MessageQueue.java b/core/java/android/os/MessageQueue.java
index 7ca5d49..01a23ce 100644
--- a/core/java/android/os/MessageQueue.java
+++ b/core/java/android/os/MessageQueue.java
@@ -16,7 +16,6 @@
package android.os;
-import android.util.AndroidRuntimeException;
import android.util.Log;
import android.util.Printer;
@@ -169,7 +168,6 @@
}
msg.next = null;
if (false) Log.v("MessageQueue", "Returning message: " + msg);
- msg.markInUse();
return msg;
}
} else {
@@ -233,7 +231,7 @@
void quit(boolean safe) {
if (!mQuitAllowed) {
- throw new RuntimeException("Main thread not allowed to quit.");
+ throw new IllegalStateException("Main thread not allowed to quit.");
}
synchronized (this) {
@@ -259,6 +257,7 @@
synchronized (this) {
final int token = mNextBarrierToken++;
final Message msg = Message.obtain();
+ msg.markInUse();
msg.when = when;
msg.arg1 = token;
@@ -303,7 +302,7 @@
mMessages = p.next;
needWake = mMessages == null || mMessages.target != null;
}
- p.recycle();
+ p.recycleUnchecked();
// If the loop is quitting then it is already awake.
// We can assume mPtr != 0 when mQuitting is false.
@@ -314,21 +313,23 @@
}
boolean enqueueMessage(Message msg, long when) {
- if (msg.isInUse()) {
- throw new AndroidRuntimeException(msg + " This message is already in use.");
- }
if (msg.target == null) {
- throw new AndroidRuntimeException("Message must have a target.");
+ throw new IllegalArgumentException("Message must have a target.");
+ }
+ if (msg.isInUse()) {
+ throw new IllegalStateException(msg + " This message is already in use.");
}
synchronized (this) {
if (mQuitting) {
- RuntimeException e = new RuntimeException(
+ IllegalStateException e = new IllegalStateException(
msg.target + " sending message to a Handler on a dead thread");
Log.w("MessageQueue", e.getMessage(), e);
+ msg.recycle();
return false;
}
+ msg.markInUse();
msg.when = when;
Message p = mMessages;
boolean needWake;
@@ -424,7 +425,7 @@
&& (object == null || p.obj == object)) {
Message n = p.next;
mMessages = n;
- p.recycle();
+ p.recycleUnchecked();
p = n;
}
@@ -435,7 +436,7 @@
if (n.target == h && n.what == what
&& (object == null || n.obj == object)) {
Message nn = n.next;
- n.recycle();
+ n.recycleUnchecked();
p.next = nn;
continue;
}
@@ -458,7 +459,7 @@
&& (object == null || p.obj == object)) {
Message n = p.next;
mMessages = n;
- p.recycle();
+ p.recycleUnchecked();
p = n;
}
@@ -469,7 +470,7 @@
if (n.target == h && n.callback == r
&& (object == null || n.obj == object)) {
Message nn = n.next;
- n.recycle();
+ n.recycleUnchecked();
p.next = nn;
continue;
}
@@ -492,7 +493,7 @@
&& (object == null || p.obj == object)) {
Message n = p.next;
mMessages = n;
- p.recycle();
+ p.recycleUnchecked();
p = n;
}
@@ -502,7 +503,7 @@
if (n != null) {
if (n.target == h && (object == null || n.obj == object)) {
Message nn = n.next;
- n.recycle();
+ n.recycleUnchecked();
p.next = nn;
continue;
}
@@ -516,7 +517,7 @@
Message p = mMessages;
while (p != null) {
Message n = p.next;
- p.recycle();
+ p.recycleUnchecked();
p = n;
}
mMessages = null;
@@ -544,7 +545,7 @@
do {
p = n;
n = p.next;
- p.recycle();
+ p.recycleUnchecked();
} while (n != null);
}
}