// This code snippet demonstrates how to resolve method call targets based on the available type information only.
// This is the basis/the first part of the CHA call graph algorithms.

import org.opalj.collection.immutable._; import org.opalj.br._ ; import org.opalj.br.analyses._; import org.opalj.br.instructions._; import org.opalj.collection.immutable.ConstArray.find; import org.opalj.util.PerformanceEvaluation.time

// 1. Create a project which also includes the RT.jar as a library.
implicit val p = Project(new java.io.File("OPAL/bi/target/scala-2.11/resource_managed/test/cg.jar"),org.opalj.bytecode.RTJar)

// 1.1. Check that the project setup is as expected; depending on the configuration the number of call targets
//		may change. 
TypeExtensibilityKey.AllClosed = true // <= "HACK" only necessary as long as we don't have a decent "isExtensiblity" analysis
val typeExtensibility = p.get(TypeExtensibilityKey)
assert(typeExtensibility(ObjectType("cg/default_methods/ISuper")).isNo /* EXPECTED: org.opalj.Answer = No */ )

val typeBasedCallTargets = p.get(TypeBasedCallTargetsKey)
typeBasedCallTargets.specialCall(ObjectType("cg/default_methods/Super"),"<init>",MethodDescriptor("()V")).map(m => m.toJava(p.classFile(m))) // EXPECTED: Set(java8methodresolution.Super{ public void <init>() })

// ALWAYS OVERRIDDEN ABSTRACT METHOD
val candidates = p.virtualCall("foo",ObjectType("cg/always_overridden/Super"),"doIt",MethodDescriptor("()V"))
typeBasedCallTargets.filterAlwaysOverriddenMethods(candidates)

// GET CALL TARGETS OF INTERFACE METHOD INVOKES (INVOKEINTERFACE)
typeBasedCallTargets.interfaceCall(ObjectType("cg/default_methods/ISuperAlt"),"compute",MethodDescriptor("(II)I"))

p.interfaceCall(ObjectType("cg/default_methods/ISuper"),"compute",MethodDescriptor("(II)I")).map(m => m.toJava(p.classFile(m))).mkString("Targets:\n\t","\n\t","\n") 
// compared to the using the project, typeBasedCallTargets does caching and performs some additional steps to further reduce the number of call targets
typeBasedCallTargets.interfaceCall(ObjectType("cg/default_methods/ISuper"),"compute",MethodDescriptor("(II)I")).map(m => m.toJava(p.classFile(m))).mkString("Targets:\n\t","\n\t","\n") 

// GET CALL TARGETS OF VIRTUAL METHOD INVOKES (INVOKEVIRTUAL)
val aDemoMain = p.classFile(ObjectType("cg/visibility/a/Demo")).get.findMethod("main").head
val invokeVirtuals = aDemoMain.body.get.collect{case i:INVOKEVIRTUAL if i.name == "printIt" => i} 
/*
invokeVirtuals.mkString("\n") ... =>
(21,INVOKEVIRTUAL(cg.visibility.a.A{ void printIt() }))
(45,INVOKEVIRTUAL(cg.visibility.a.A{ void printIt() }))
(69,INVOKEVIRTUAL(cg.visibility.a.A{ void printIt() }))
(96,INVOKEVIRTUAL(cg.visibility.a.C{ void printIt() }))
*/

val pts = p.virtualCall("cg/visibility/a",invokeVirtuals(0)._2).map(m => m.toJava(p.classFile(m)))
val tts = typeBasedCallTargets.virtualCall("cg/visibility/a",invokeVirtuals(0)._2)
pts eq tts // => false
tts eq typeBasedCallTargets.virtualCall("cg/visibility/a",invokeVirtuals(0)._2)// => true (results are cached)

p.virtualCall("cg/visibility/a",invokeVirtuals(0)._2).map(m => m.toJava(p.classFile(m)))
//res: scala.collection.immutable.Set[String] = Set(cg.visibility.a.C{ protected void printIt() }, cg.visibility.a.A{ void printIt() })

p.virtualCall("cg/visibility/a",invokeVirtuals(3)._2).map(m => m.toJava(p.classFile(m)))
//res: scala.collection.immutable.Set[String] = Set(cg.visibility.a.C{ protected void printIt() })

p.virtualCall("cg/visibility/b",invokeVirtuals(3)._2).map(m => m.toJava(p.classFile(m)))
//res: scala.collection.immutable.Set[String] = Set(cg.visibility.a.C{ protected void printIt() })

p.virtualCall("cg/visibility/b",invokeVirtuals(0)._2).map(m => m.toJava(p.classFile(m)))
//res: scala.collection.immutable.Set[String] = Set(cg.visibility.b.B{ protected void printIt() }, cg.visibility.a.C{ protected void printIt() })

// LOOKUP OF ARRAY BASED METHOD CALLS
typeBasedCallTargets.virtualCall("N/A",ArrayType(ObjectType("java/lang/Object")),"hashCode",MethodDescriptor("()I"))

typeBasedCallTargets.virtualCall("foo",ObjectType("cg/always_overridden/Super"),"doIt",MethodDescriptor("()V"))