/*
* 在'clazz'中，我们有一个方法指向另一个方法，但它可能指向派生类中的一个方法，我们想要从虚拟函数表中找到实际入口,如果'class'是一个接口，我们不得不在短时间内做更多的挖掘
*
* 对于'direct'方法(private / constructor).我们仅仅返回原生态方法
*
* (这里被适用于反射和JNI调用)
*/
const Method* dvmGetVirtualizedMethod(const ClassObject* clazz,
const Method* meth)
{
Method* actualMeth;
int methodIndex;
if (dvmIsDirectMethod(meth)) {
/* no vtable entry for these */
assert(!dvmIsStaticMethod(meth));
return meth;
}
/*
* If the method was declared in an interface, we need to scan through
* the class' list of interfaces for it, and find the vtable index
* from that.
*
* TODO: use the interface cache.
*/
if (dvmIsInterfaceClass(meth->clazz)) {
int i;
for (i = 0; i < clazz->iftableCount; i++) {
if (clazz->iftable[i].clazz == meth->clazz)
break;
}
if (i == clazz->iftableCount) {
dvmThrowIncompatibleClassChangeError(
"invoking method from interface not implemented by class");
return NULL;
}
methodIndex = clazz->iftable[i].methodIndexArray[meth->methodIndex];
} else {
methodIndex = meth->methodIndex;
}
assert(methodIndex >= 0 && methodIndex < clazz->vtableCount);
actualMeth = clazz->vtable[methodIndex];
/*
* Make sure there's code to execute.
*/
if (dvmIsAbstractMethod(actualMeth)) {
dvmThrowAbstractMethodError(NULL);
return NULL;
}
assert(!dvmIsMirandaMethod(actualMeth));
return actualMeth;
}
/*
* Convert a method pointer to a slot number.
*
* We use positive values starting from 0 for virtual methods, negative
* values starting from -1 for static methods.
*/
static int methodToSlot(const Method* meth)
{
ClassObject* clazz = meth->clazz;
int slot;
if (dvmIsDirectMethod(meth)) {
slot = meth - clazz->directMethods;
assert(slot >= 0 && slot < clazz->directMethodCount);
slot = -(slot+1);
} else {
slot = meth - clazz->virtualMethods;
assert(slot >= 0 && slot < clazz->virtualMethodCount);
}
return slot;
}
