/*
* Returns true if the reference was registered with a reference queue
* and has not yet been enqueued.
*/
static jboolean isEnqueuable(Env* env, Object* reference) {
// This code is a port of the isEnqueuable() function in Android's MarkSweep.cpp
assert(reference != NULL);
Object* queue = rvmGetObjectInstanceFieldValue(env, reference, java_lang_ref_Reference_queue);
Object* queueNext = rvmGetObjectInstanceFieldValue(env, reference, java_lang_ref_Reference_queueNext);
return (queue != NULL && queueNext == NULL) ? TRUE : FALSE;
}
/*
* Removes the reference at the head of a circular queue of
* references.
*/
static Object* dequeuePendingReference(Env* env, Object** list) {
// This code is a port of the dequeuePendingReference() function in Android's MarkSweep.cpp
assert(list != NULL);
assert(*list != NULL);
// head = list.pendingNext
Object* head = rvmGetObjectInstanceFieldValue(env, *list, java_lang_ref_Reference_pendingNext);
Object* ref;
if (*list == head) {
ref = *list;
*list = NULL;
} else {
// next = head.pendingNext
Object* next = rvmGetObjectInstanceFieldValue(env, head, java_lang_ref_Reference_pendingNext);
// list.pendingNext = next
rvmSetObjectInstanceFieldValue(env, *list, java_lang_ref_Reference_pendingNext, next);
ref = head;
}
rvmSetObjectInstanceFieldValue(env, ref, java_lang_ref_Reference_pendingNext, NULL);
return ref;
}
/*
* Adds a reference to the tail of a circular queue of references.
*/
static void enqueuePendingReference(Env* env, Object* ref, Object** list) {
// This code is a port of the enqueuePendingReference() function in Android's MarkSweep.cpp
if (*list == NULL) {
// ref.pendingNext = ref
rvmSetObjectInstanceFieldValue(env, ref, java_lang_ref_Reference_pendingNext, ref);
*list = ref;
} else {
// head = list.pendingNext
Object* head = rvmGetObjectInstanceFieldValue(env, *list, java_lang_ref_Reference_pendingNext);
// ref.pendingNext = head
rvmSetObjectInstanceFieldValue(env, ref, java_lang_ref_Reference_pendingNext, head);
// list.pendingNext = ref
rvmSetObjectInstanceFieldValue(env, *list, java_lang_ref_Reference_pendingNext, ref);
}
}
/*
* Unlink the reference list clearing references objects with unreachable
* referents. Cleared references registered to a reference queue are
* enqueued on the cleared list.
*/
static void clearAndEnqueueReferences(Env* env, Object** list, Object** cleared) {
// This code is a port of the clearWhiteReferences() function in Android's MarkSweep.cpp
assert(list != NULL);
assert(cleared != NULL);
while (*list != NULL) {
Object* ref = dequeuePendingReference(env, list);
Object* referent = rvmGetObjectInstanceFieldValue(env, ref, java_lang_ref_Reference_referent);
if (referent != NULL) {
clearReference(env, ref);
if (isEnqueuable(env, ref)) {
enqueueReference(env, ref, cleared);
}
}
}
assert(*list == NULL);
}
/*
* Enqueues finalizer references with unreachable referents. The
* referent is moved to the zombie field (which makes it reachable again),
* and the referent field is cleared.
*/
static void enqueueFinalizerReferences(Env* env, Object** list, Object** cleared) {
// This code is a port of the enqueueFinalizerReferences() function in Android's MarkSweep.cpp
assert(list != NULL);
while (*list != NULL) {
Object* ref = dequeuePendingReference(env, list);
Object* referent = rvmGetObjectInstanceFieldValue(env, ref, java_lang_ref_Reference_referent);
if (referent != NULL) {
/* If the referent is non-null the reference must queuable. */
assert(isEnqueuable(env, ref));
// Copy the referent to the zombie field
rvmSetObjectInstanceFieldValue(env, ref, java_lang_ref_FinalizerReference_zombie, referent);
// Clear the referent
clearReference(env, ref);
enqueueReference(env, ref, cleared);
}
}
assert(*list == NULL);
}
static jobject GetObjectField(JNIEnv* env, jobject obj, jfieldID fieldID) {
return (jobject) rvmGetObjectInstanceFieldValue((Env*) env, (Object*) obj, (InstanceField*) fieldID);
}
