private void installParameters(boolean isStatic, String className) throws TypeException {
Type type;
// add a binding for the helper so we can call builtin static methods
type = typeGroup.create(helperClass.getName());
Binding ruleBinding = bindings.lookup("$$");
if (ruleBinding != null) {
ruleBinding.setType(type);
} else {
bindings.append(new Binding(this, "$$", type));
}
if (!isStatic) {
Binding recipientBinding = bindings.lookup("$0");
if (recipientBinding != null) {
type = typeGroup.create(className);
if (type.isUndefined()) {
throw new TypeException(
"Rule.installParameters : Rule " + name + " unable to load class " + className);
}
recipientBinding.setType(type);
}
}
String returnTypeName = Type.parseMethodReturnType(triggerDescriptor);
returnType = typeGroup.create(returnTypeName);
Iterator<Binding> iterator = bindings.iterator();
while (iterator.hasNext()) {
Binding binding = iterator.next();
// these bindings are typed via the descriptor installed during trigger injection
// note that the return type has to be done this way because it may represent the
// trigger method return type or the invoke method return type
if (binding.isParam() || binding.isLocalVar() || binding.isReturn()) {
String typeName = binding.getDescriptor();
String[] typeAndArrayBounds = typeName.split("\\[");
Type baseType = typeGroup.create(typeAndArrayBounds[0]);
Type fullType = baseType;
if (baseType.isUndefined()) {
throw new TypeException(
"Rule.installParameters : Rule " + name + " unable to load class " + baseType);
}
for (int i = 1; i < typeAndArrayBounds.length; i++) {
fullType = typeGroup.createArray(fullType);
}
binding.setType(fullType);
} else if (binding.isThrowable()) {
// TODO -- enable a more precise specification of the throwable type
// we need to be able to obtain the type descriptor for the throw operation
binding.setType(typeGroup.ensureType(Throwable.class));
} else if (binding.isParamCount()) {
binding.setType(Type.I);
} else if (binding.isParamArray() || binding.isInvokeParamArray()) {
binding.setType(Type.OBJECT.arrayType());
} else if (binding.isTriggerClass() || binding.isTriggerMethod()) {
binding.setType(Type.STRING);
}
}
}
/**
* find a method to resolve this method call expression.
*
* @param publicOnly true if only public methods should be considered
* @throws TypeException
*/
private void findMethod(boolean publicOnly) throws TypeException {
// check all declared methods of each class in the class hierarchy using the one with
// the most specific recipient type if we can find it
TypeGroup typeGroup = getTypeGroup();
Class<?> clazz = rootType.getTargetClass();
boolean isStatic = (recipient == null);
int arity = arguments.size();
LinkedList<Class<?>> clazzes = new LinkedList<Class<?>>();
if (publicOnly) {
// we can use getDeclaredMethods on just one class to list all possible candidates
clazzes.add(clazz);
} else {
// we need to iterate over the class and interface hierarchy bottom up
while (clazz != null) {
clazzes.add(clazz);
// collect all direct interfaces in order
Class[] ifaces = clazz.getInterfaces();
LinkedList<Class<?>> toBeChecked = new LinkedList<Class<?>>();
for (int i = 0; i < ifaces.length; i++) {
toBeChecked.addLast(ifaces[i]);
}
// process each interface in turn, also collecting its parent interfaces for consideration
while (!toBeChecked.isEmpty()) {
Class<?> iface = toBeChecked.pop();
// only need to process it if we have not already seen it
if (!clazzes.contains(iface)) {
clazzes.addLast(iface);
Class[] ifaces2 = iface.getInterfaces();
// don't bother to check for repeats here as we check later anyway
for (int j = 0; j < ifaces2.length; j++) {
toBeChecked.addLast(ifaces2[j]);
}
}
}
// move on to the next class
clazz = clazz.getSuperclass();
}
}
// now check for a matching method in each class or interface in order
while (!clazzes.isEmpty()) {
clazz = clazzes.pop();
List<Method> candidates = new ArrayList<Method>();
try {
Method[] methods;
if (publicOnly) {
methods = clazz.getMethods();
} else {
methods = clazz.getDeclaredMethods();
}
argumentTypes = new ArrayList<Type>();
for (Method method : methods) {
int modifiers = method.getModifiers();
// ensure we only look at static or non static methods as appropriate
if (Modifier.isStatic(modifiers) == isStatic) {
if (method.getName().equals(name) && method.getParameterTypes().length == arity) {
candidates.add(method);
}
}
}
// check each argument in turn -- if all candidates have the same argument type then
// use that as the type to check against
for (int i = 0; i < arguments.size(); i++) {
if (candidates.isEmpty()) {
// no more possible matches
break;
}
Class candidateClass = getCandidateArgClass(candidates, i);
Type candidateType;
if (candidateClass != null) {
candidateType = typeGroup.ensureType(candidateClass);
} else {
candidateType = Type.UNDEFINED;
}
Type argType = arguments.get(i).typeCheck(candidateType);
argumentTypes.add(argType);
if (candidateType == Type.UNDEFINED) {
// we had several methods to choose from
candidates = pruneCandidates(candidates, i, argType.getTargetClass());
}
}
// see if we have a unique best fit
Method method = bestMatchCandidate(candidates);
if (method != null) {
if (!Modifier.isPublic(method.getModifiers())) {
// see if we can actually access this method
try {
method.setAccessible(true);
} catch (SecurityException e) {
// hmm, maybe try the next super
continue;
}
// we need to remember that this is not public
isPublicMethod = false;
// save the method so we can use it from the compiled code
methodIndex = rule.addAccessibleMethod(method);
} else {
isPublicMethod = true;
}
this.method = method;
return;
} else if (candidates.size() > 1) {
// ambiguous method so throw up here
throw new TypeException(
"MethodExpression.typeCheck : ambiguous method signature "
+ name
+ " for target class "
+ rootType.getName()
+ getPos());
}
} catch (SecurityException e) {
// continue in case we can find an implementation
}
}
// no more possible candidates so throw up here
throw new TypeException(
"MethodExpression.typeCheck : invalid method "
+ name
+ " for target class "
+ rootType.getName()
+ getPos());
}
public void compile(MethodVisitor mv, CompileContext compileContext) throws CompileException {
// make sure we are at the right source line
compileContext.notifySourceLine(line);
int currentStack = compileContext.getStackCount();
int extraParams = 0; // space used by stacked args after conversion
int expected = 0;
// no need for type conversion as return type was derived from method
if (type.getNBytes() > 4) {
expected = 2;
} else if (type != Type.VOID) {
expected = 1;
} else {
expected = 0;
}
int argCount = arguments.size();
if (isPublicMethod) {
// we can just do this as a direct call
// stack the recipient if necessary then stack the args and then invoke the method
if (recipient != null) {
// compile code for recipient
recipient.compile(mv, compileContext);
extraParams += 1;
}
for (int i = 0; i < argCount; i++) {
Expression argument = arguments.get(i);
Type argType = argumentTypes.get(i);
Type paramType = paramTypes.get(i);
// compile code to stack argument and type convert if necessary
argument.compile(mv, compileContext);
compileTypeConversion(argType, paramType, mv, compileContext);
// allow for stacked paramType value
extraParams += (paramType.getNBytes() > 4 ? 2 : 1);
}
// enable triggering before we call the method
// this adds an extra value to the stack so modify the compile context to ensure
// we increase the maximum height if necessary
mv.visitMethodInsn(
Opcodes.INVOKESTATIC, "org/jboss/byteman/rule/Rule", "enableTriggersInternal", "()Z");
compileContext.addStackCount(1);
mv.visitInsn(Opcodes.POP);
compileContext.addStackCount(-1);
// ok, now just call the method -- removes extraParams words
String ownerName = Type.internalName(method.getDeclaringClass());
if (recipient == null) {
mv.visitMethodInsn(Opcodes.INVOKESTATIC, ownerName, method.getName(), getDescriptor());
} else if (method.getDeclaringClass().isInterface()) {
mv.visitMethodInsn(Opcodes.INVOKEINTERFACE, ownerName, method.getName(), getDescriptor());
} else {
mv.visitMethodInsn(Opcodes.INVOKEVIRTUAL, ownerName, method.getName(), getDescriptor());
}
// decrement the stack height to account for stacked param values (removed) and return value
// (added)
compileContext.addStackCount(expected - extraParams);
// now disable triggering again
// this temporarily adds an extra value to the stack -- n.b. we *must* increment and
// then decrement the stack height even though we bumped the max before the call. in
// some cases the stack may be larger after the method call than before e.g. calling
// a static which returns a value or calling a non-static which returns a long/double
mv.visitMethodInsn(
Opcodes.INVOKESTATIC, "org/jboss/byteman/rule/Rule", "disableTriggersInternal", "()Z");
compileContext.addStackCount(1);
mv.visitInsn(Opcodes.POP);
compileContext.addStackCount(-1);
} else {
// if we are calling a method by reflection then we need to stack the current helper then
// the recipient or null if there is none and then build an object array on the stack
mv.visitVarInsn(Opcodes.ALOAD, 0);
compileContext.addStackCount(1);
if (recipient != null) {
// compile code for recipient
recipient.compile(mv, compileContext);
} else {
mv.visitInsn(Opcodes.ACONST_NULL);
compileContext.addStackCount(1);
}
// stack arg count then create a new array
mv.visitLdcInsn(argCount);
compileContext.addStackCount(1);
// this just swaps one word for another
mv.visitTypeInsn(Opcodes.ANEWARRAY, "java/lang/Object");
// duplicate the array, stack the index, compile code to generate the arg and the do an array
// put
for (int i = 0; i < argCount; i++) {
mv.visitInsn(Opcodes.DUP);
mv.visitLdcInsn(i);
// that was two extra words
compileContext.addStackCount(2);
Expression argument = arguments.get(i);
Type argType = argumentTypes.get(i);
Type paramType = paramTypes.get(i);
// compile code to stack argument and type convert/box if necessary
argument.compile(mv, compileContext);
compileTypeConversion(argType, paramType, mv, compileContext);
compileBox(paramType, mv, compileContext);
// that's 3 extra words which now get removed
mv.visitInsn(Opcodes.AASTORE);
compileContext.addStackCount(-3);
}
// now stack the method object index
mv.visitLdcInsn(methodIndex);
compileContext.addStackCount(1);
// enable triggering before we call the method
// this adds an extra value to the stack so modify the compile context to ensure
// we increase the maximum height if necessary
mv.visitMethodInsn(
Opcodes.INVOKESTATIC, "org/jboss/byteman/rule/Rule", "enableTriggersInternal", "()Z");
compileContext.addStackCount(1);
mv.visitInsn(Opcodes.POP);
compileContext.addStackCount(-1);
// ok, we now have the recipient, args array and method index on the stack
// so we can call the HelperAdapter method to do the actual reflective invocation
mv.visitMethodInsn(
Opcodes.INVOKEINTERFACE,
Type.internalName(HelperAdapter.class),
"invokeAccessibleMethod",
"(Ljava/lang/Object;[Ljava/lang/Object;I)Ljava/lang/Object;");
// we popped 4 words and left one in its place
compileContext.addStackCount(-3);
if (type == Type.VOID) {
mv.visitInsn(Opcodes.POP);
compileContext.addStackCount(-1);
} else {
// do any necessary casting and/or unboxing
compileTypeConversion(Type.OBJECT, type, mv, compileContext);
}
// now disable triggering again
// this temporarily adds an extra value to the stack -- n.b. no need to increment and
// then decrement the stack height here because the previous enable call will already have
// bumped the max when we had 4 slots on the stack and any return value on the stack will
// occupy at most 2 slots
mv.visitMethodInsn(
Opcodes.INVOKESTATIC, "org/jboss/byteman/rule/Rule", "disableTriggersInternal", "()Z");
compileContext.addStackCount(1);
mv.visitInsn(Opcodes.POP);
compileContext.addStackCount(-1);
}
// ensure we have only increased the stack by the return value size
if (compileContext.getStackCount() != currentStack + expected) {
throw new CompileException(
"MethodExpression.compile : invalid stack height "
+ compileContext.getStackCount()
+ " expecting "
+ (currentStack + expected));
}
// no need to update max stack since compiling the recipient or arguments will
// have done so (and there will be no change if there was no such compile call)
}
public Type typeCheck(Type expected) throws TypeException {
// if we have no recipient then we use the rule's helper as a target via a binding
// to $-1. this means we can type check the call against methods of class Helper
// without having to do any special case processing.
TypeGroup typeGroup = getTypeGroup();
if (recipient == null && pathList != null) {
// treat the pathlist as a typename or a static field dereference possibly combined with
// further field dereferences
// factor off a typename from the path
Type rootType = typeGroup.match(pathList);
if (rootType == null) {
throw new TypeException(
"MethodExpression.typeCheck : invalid path "
+ getPath(pathList.length)
+ " to static method "
+ name
+ getPos());
}
// find out how many of the path elements are included in the type name
String rootTypeName = rootType.getName();
int idx = getPathCount(rootTypeName);
if (idx < pathList.length) {
// create a static field reference using the type name and the first field name and wrap it
// with
// enough field references to use up all the path
String fieldName = pathList[idx++];
Expression recipient =
new StaticExpression(rule, Type.UNDEFINED, token, fieldName, rootTypeName);
while (idx < pathList.length) {
recipient =
new FieldExpression(rule, Type.UNDEFINED, token, pathList[idx++], recipient, null);
}
this.recipient = recipient;
} else {
// ok, this method reference is actually a static method call -- record the root type for
// later
this.recipient = null;
this.rootType = rootType;
}
// get rid of the path list now
this.pathList = null;
// not strictly necessary?
if (this.recipient != null) {
this.recipient.bind();
}
}
// if we don't have a recipient and we didn't find a static class for the method then this is
// a builtin
boolean isBuiltIn = false;
if (recipient == null) {
if (rootType == null) {
isBuiltIn = true;
Type ruleType = typeGroup.create(rule.getHelperClass().getCanonicalName());
recipient = new DollarExpression(rule, ruleType, token, DollarExpression.HELPER_IDX);
recipient.bind();
rootType = recipient.typeCheck(Type.UNDEFINED);
}
} else {
rootType = recipient.typeCheck(Type.UNDEFINED);
}
// see if we can find a method for this call
findMethod(isBuiltIn);
// now go back and identify the parameter types
this.paramTypes = new ArrayList<Type>();
Class<?>[] paramClasses = method.getParameterTypes();
for (int i = 0; i < arguments.size(); i++) {
Class<?> paramClass = paramClasses[i];
paramTypes.add(typeGroup.ensureType(paramClass));
}
type = typeGroup.ensureType(method.getReturnType());
if (Type.dereference(expected).isDefined() && !expected.isAssignableFrom(type)) {
throw new TypeException(
"MethodExpression.typeCheck : invalid expected type " + expected.getName() + getPos());
}
return type;
}
