/*
* Resolve an interface method reference.
*
* Returns NULL with an exception raised on failure.
*/
Method* dvmResolveInterfaceMethod(const ClassObject* referrer, u4 methodIdx)
{
DvmDex* pDvmDex = referrer->pDvmDex;
ClassObject* resClass;
const DexMethodId* pMethodId;
Method* resMethod;
int i;
LOGVV("--- resolving interface method %d (referrer=%s)\n",
methodIdx, referrer->descriptor);
pMethodId = dexGetMethodId(pDvmDex->pDexFile, methodIdx);
resClass = dvmResolveClass(referrer, pMethodId->classIdx, false);
if (resClass == NULL) {
/* can't find the class that the method is a part of */
assert(dvmCheckException(dvmThreadSelf()));
return NULL;
}
if (!dvmIsInterfaceClass(resClass)) {
/* whoops */
dvmThrowExceptionWithClassMessage(
"Ljava/lang/IncompatibleClassChangeError;",
resClass->descriptor);
return NULL;
}
/*
* This is the first time the method has been resolved. Set it in our
* resolved-method structure. It always resolves to the same thing,
* so looking it up and storing it doesn't create a race condition.
*
* If we scan into the interface's superclass -- which is always
* java/lang/Object -- we will catch things like:
* interface I ...
* I myobj = (something that implements I)
* myobj.hashCode()
* However, the Method->methodIndex will be an offset into clazz->vtable,
* rather than an offset into clazz->iftable. The invoke-interface
* code can test to see if the method returned is abstract or concrete,
* and use methodIndex accordingly. I'm not doing this yet because
* (a) we waste time in an unusual case, and (b) we're probably going
* to fix it in the DEX optimizer.
*
* We do need to scan the superinterfaces, in case we're invoking a
* superinterface method on an interface reference. The class in the
* DexTypeId is for the static type of the object, not the class in
* which the method is first defined. We have the full, flattened
* list in "iftable".
*/
const char* methodName =
dexStringById(pDvmDex->pDexFile, pMethodId->nameIdx);
DexProto proto;
dexProtoSetFromMethodId(&proto, pDvmDex->pDexFile, pMethodId);
LOGVV("+++ looking for '%s' '%s' in resClass='%s'\n",
methodName, methodSig, resClass->descriptor);
resMethod = dvmFindVirtualMethod(resClass, methodName, &proto);
if (resMethod == NULL) {
LOGVV("+++ did not resolve immediately\n");
for (i = 0; i < resClass->iftableCount; i++) {
resMethod = dvmFindVirtualMethod(resClass->iftable[i].clazz,
methodName, &proto);
if (resMethod != NULL)
break;
}
if (resMethod == NULL) {
dvmThrowException("Ljava/lang/NoSuchMethodError;", methodName);
return NULL;
}
} else {
LOGVV("+++ resolved immediately: %s (%s %d)\n", resMethod->name,
resMethod->clazz->descriptor, (u4) resMethod->methodIndex);
}
LOGVV("--- found interface method %d (%s.%s)\n",
methodIdx, resClass->descriptor, resMethod->name);
/* we're expecting this to be abstract */
assert(dvmIsAbstractMethod(resMethod));
/* interface methods are always public; no need to check access */
/*
* The interface class *may* be initialized. According to VM spec
* v2 2.17.4, the interfaces a class refers to "need not" be initialized
* when the class is initialized.
*
* It isn't necessary for an interface class to be initialized before
* we resolve methods on that interface.
*
* We choose not to do the initialization now.
*/
//assert(dvmIsClassInitialized(resMethod->clazz));
/*
* The class is initialized, the method has been found. Add a pointer
* to our data structure so we don't have to jump through the hoops again.
*/
dvmDexSetResolvedMethod(pDvmDex, methodIdx, resMethod);
return resMethod;
}
/*
* This is the common message body for proxy methods.
*
* The method we're calling looks like:
* public Object invoke(Object proxy, Method method, Object[] args)
*
* This means we have to create a Method object, box our arguments into
* a new Object[] array, make the call, and unbox the return value if
* necessary.
*/
static void proxyInvoker(const u4* args, JValue* pResult,
const Method* method, Thread* self)
{
Object* thisObj = (Object*) args[0];
Object* methodObj = NULL;
ArrayObject* argArray = NULL;
Object* handler;
Method* invoke;
ClassObject* returnType;
int hOffset;
JValue invokeResult;
/*
* Retrieve handler object for this proxy instance.
*/
hOffset = dvmFindFieldOffset(thisObj->clazz, "h",
"Ljava/lang/reflect/InvocationHandler;");
if (hOffset < 0) {
LOGE("Unable to find 'h' in Proxy object\n");
dvmAbort();
}
handler = dvmGetFieldObject(thisObj, hOffset);
/*
* Find the invoke() method, looking in "this"s class. (Because we
* start here we don't have to convert it to a vtable index and then
* index into this' vtable.)
*/
invoke = dvmFindVirtualMethodHierByDescriptor(handler->clazz, "invoke",
"(Ljava/lang/Object;Ljava/lang/reflect/Method;[Ljava/lang/Object;)Ljava/lang/Object;");
if (invoke == NULL) {
LOGE("Unable to find invoke()\n");
dvmAbort();
}
LOGV("invoke: %s.%s, this=%p, handler=%s\n",
method->clazz->descriptor, method->name,
thisObj, handler->clazz->descriptor);
/*
* Create a java.lang.reflect.Method object for this method.
*
* We don't want to use "method", because that's the concrete
* implementation in the proxy class. We want the abstract Method
* from the declaring interface. We have a pointer to it tucked
* away in the "insns" field.
*
* TODO: this could be cached for performance.
*/
methodObj = dvmCreateReflectMethodObject((Method*) method->insns);
if (methodObj == NULL) {
assert(dvmCheckException(self));
goto bail;
}
/*
* Determine the return type from the signature.
*
* TODO: this could be cached for performance.
*/
returnType = dvmGetBoxedReturnType(method);
if (returnType == NULL) {
char* desc = dexProtoCopyMethodDescriptor(&method->prototype);
LOGE("Could not determine return type for '%s'\n", desc);
free(desc);
assert(dvmCheckException(self));
goto bail;
}
LOGV(" return type will be %s\n", returnType->descriptor);
/*
* Convert "args" array into Object[] array, using the method
* signature to determine types. If the method takes no arguments,
* we must pass null.
*/
argArray = boxMethodArgs(method, args+1);
if (dvmCheckException(self))
goto bail;
/*
* Call h.invoke(proxy, method, args).
*
* We don't need to repackage exceptions, so if one has been thrown
* just jump to the end.
*/
dvmCallMethod(self, invoke, handler, &invokeResult,
thisObj, methodObj, argArray);
if (dvmCheckException(self))
goto bail;
/*
* Unbox the return value. If it's the wrong type, throw a
* ClassCastException. If it's a null pointer and we need a
* primitive type, throw a NullPointerException.
*/
if (returnType->primitiveType == PRIM_VOID) {
LOGVV("+++ ignoring return to void\n");
} else if (invokeResult.l == NULL) {
if (dvmIsPrimitiveClass(returnType)) {
dvmThrowException("Ljava/lang/NullPointerException;",
"null result when primitive expected");
goto bail;
}
pResult->l = NULL;
} else {
if (!dvmUnwrapPrimitive(invokeResult.l, returnType, pResult)) {
dvmThrowExceptionWithClassMessage("Ljava/lang/ClassCastException;",
((Object*)invokeResult.l)->clazz->descriptor);
goto bail;
}
}
bail:
dvmReleaseTrackedAlloc(methodObj, self);
dvmReleaseTrackedAlloc((Object*)argArray, self);
}
/*
* Find the method corresponding to "methodRef".
*
* We use "referrer" to find the DexFile with the constant pool that
* "methodRef" is an index into. We also use its class loader. The method
* being resolved may very well be in a different DEX file.
*
* If this is a static method, we ensure that the method's class is
* initialized.
*/
Method* dvmResolveMethod(const ClassObject* referrer, u4 methodIdx,
MethodType methodType)
{
DvmDex* pDvmDex = referrer->pDvmDex;
ClassObject* resClass;
const DexMethodId* pMethodId;
Method* resMethod;
assert(methodType != METHOD_INTERFACE);
LOGVV("--- resolving method %u (referrer=%s)\n", methodIdx,
referrer->descriptor);
pMethodId = dexGetMethodId(pDvmDex->pDexFile, methodIdx);
resClass = dvmResolveClass(referrer, pMethodId->classIdx, false);
if (resClass == NULL) {
/* can't find the class that the method is a part of */
assert(dvmCheckException(dvmThreadSelf()));
return NULL;
}
if (dvmIsInterfaceClass(resClass)) {
/* method is part of an interface */
dvmThrowExceptionWithClassMessage(
"Ljava/lang/IncompatibleClassChangeError;",
resClass->descriptor);
return NULL;
}
const char* name = dexStringById(pDvmDex->pDexFile, pMethodId->nameIdx);
DexProto proto;
dexProtoSetFromMethodId(&proto, pDvmDex->pDexFile, pMethodId);
/*
* We need to chase up the class hierarchy to find methods defined
* in super-classes. (We only want to check the current class
* if we're looking for a constructor; since DIRECT calls are only
* for constructors and private methods, we don't want to walk up.)
*/
if (methodType == METHOD_DIRECT) {
resMethod = dvmFindDirectMethod(resClass, name, &proto);
} else if (methodType == METHOD_STATIC) {
resMethod = dvmFindDirectMethodHier(resClass, name, &proto);
} else {
resMethod = dvmFindVirtualMethodHier(resClass, name, &proto);
}
if (resMethod == NULL) {
dvmThrowException("Ljava/lang/NoSuchMethodError;", name);
return NULL;
}
LOGVV("--- found method %d (%s.%s)\n",
methodIdx, resClass->descriptor, resMethod->name);
/* see if this is a pure-abstract method */
if (dvmIsAbstractMethod(resMethod) && !dvmIsAbstractClass(resClass)) {
dvmThrowException("Ljava/lang/AbstractMethodError;", name);
return NULL;
}
/*
* If we're the first to resolve this class, we need to initialize
* it now. Only necessary for METHOD_STATIC.
*/
if (methodType == METHOD_STATIC) {
if (!dvmIsClassInitialized(resMethod->clazz) &&
!dvmInitClass(resMethod->clazz))
{
assert(dvmCheckException(dvmThreadSelf()));
return NULL;
} else {
assert(!dvmCheckException(dvmThreadSelf()));
}
} else {
/*
* Edge case: if the <clinit> for a class creates an instance
* of itself, we will call <init> on a class that is still being
* initialized by us.
*/
assert(dvmIsClassInitialized(resMethod->clazz) ||
dvmIsClassInitializing(resMethod->clazz));
}
/*
* The class is initialized, the method has been found. Add a pointer
* to our data structure so we don't have to jump through the hoops again.
*/
dvmDexSetResolvedMethod(pDvmDex, methodIdx, resMethod);
return resMethod;
}
