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// natMethod.cc - Native code for Method class.

/* Copyright (C) 1998, 1999, 2000, 2001 , 2002, 2003, 2004, 2005 Free Software Foundation

   This file is part of libgcj.

This software is copyrighted work licensed under the terms of the

Libgcj License.  Please consult the file "LIBGCJ_LICENSE" for

details.  */

#include <config.h>

#include <gcj/cni.h>

#include <jvm.h>

#include <jni.h>

#include <java-stack.h>

#include <java/lang/reflect/Method.h>

#include <java/lang/reflect/Constructor.h>

#include <java/lang/reflect/InvocationTargetException.h>

#include <java/lang/reflect/Modifier.h>

#include <java/lang/Void.h>

#include <java/lang/Byte.h>

#include <java/lang/Boolean.h>

#include <java/lang/Character.h>

#include <java/lang/Short.h>

#include <java/lang/Integer.h>

#include <java/lang/Long.h>

#include <java/lang/Float.h>

#include <java/lang/Double.h>

#include <java/lang/IllegalAccessException.h>

#include <java/lang/IllegalArgumentException.h>

#include <java/lang/IncompatibleClassChangeError.h>

#include <java/lang/NullPointerException.h>

#include <java/lang/ArrayIndexOutOfBoundsException.h>

#include <java/lang/VirtualMachineError.h>

#include <java/lang/Class.h>

#include <gcj/method.h>

#include <gnu/gcj/RawData.h>

#include <java/lang/NoClassDefFoundError.h>

#include <stdlib.h>

#if USE_LIBFFI

#include <ffi.h>

#else

#include <java/lang/UnsupportedOperationException.h>

#endif

struct cpair

{

  jclass prim;

  jclass wrap;

};

// This is used to determine when a primitive widening conversion is

// allowed.

static cpair primitives[] =

{

#define BOOLEAN 0

  { JvPrimClass (boolean), &java::lang::Boolean::class$ },

  { JvPrimClass (byte), &java::lang::Byte::class$ },

#define SHORT 2

  { JvPrimClass (short), &java::lang::Short::class$ },

#define CHAR 3

  { JvPrimClass (char), &java::lang::Character::class$ },

  { JvPrimClass (int), &java::lang::Integer::class$ },

  { JvPrimClass (long), &java::lang::Long::class$ },

  { JvPrimClass (float), &java::lang::Float::class$ },

  { JvPrimClass (double), &java::lang::Double::class$ },

  { NULL, NULL }

};

static inline jboolean

can_widen (jclass from, jclass to)

{

  int fromx = -1, tox = -1;

  for (int i = 0; primitives[i].prim; ++i)

    {

      if (primitives[i].wrap == from)

        fromx = i;

      if (primitives[i].prim == to)

        tox = i;

    }

  // Can't handle a miss.

  if (fromx == -1 || tox == -1)

    return false;

  // Boolean arguments may not be widened.

  if (fromx == BOOLEAN && tox != BOOLEAN)

    return false;

  // Nothing promotes to char.

  if (tox == CHAR && fromx != CHAR)

    return false;

  return fromx <= tox;

}

#ifdef USE_LIBFFI

static inline ffi_type *

get_ffi_type (jclass klass)

{

  // A special case.

  if (klass == NULL)

    return &ffi_type_pointer;

  ffi_type *r;

  if (klass == JvPrimClass (byte))

    r = &ffi_type_sint8;

  else if (klass == JvPrimClass (short))

    r = &ffi_type_sint16;

  else if (klass == JvPrimClass (int))

    r = &ffi_type_sint32;

  else if (klass == JvPrimClass (long))

    r = &ffi_type_sint64;

  else if (klass == JvPrimClass (float))

    r = &ffi_type_float;

  else if (klass == JvPrimClass (double))

    r = &ffi_type_double;

  else if (klass == JvPrimClass (boolean))

    {

      // On some platforms a bool is a byte, on others an int.

      if (sizeof (jboolean) == sizeof (jbyte))

        r = &ffi_type_sint8;

      else

        {

          JvAssert (sizeof (jboolean) == sizeof (jint));

          r = &ffi_type_sint32;

        }

    }

  else if (klass == JvPrimClass (char))

    r = &ffi_type_uint16;

  else

    {

      JvAssert (! klass->isPrimitive());

      r = &ffi_type_pointer;

    }

  return r;

}

#endif // USE_LIBFFI

jobject

java::lang::reflect::Method::invoke (jobject obj, jobjectArray args)

{

  using namespace java::lang::reflect;

  jclass iface = NULL;

  if (parameter_types == NULL)

    getType ();

  jmethodID meth = _Jv_FromReflectedMethod (this);

  if (Modifier::isStatic(meth->accflags))

    {

      // We have to initialize a static class.  It is safe to do this

      // here and not in _Jv_CallAnyMethodA because JNI initializes a

      // class whenever a method lookup is done.

      _Jv_InitClass (declaringClass);

    }

  else

    {

      jclass objClass = JV_CLASS (obj);

      if (! _Jv_IsAssignableFrom (objClass, declaringClass))

        throw new java::lang::IllegalArgumentException;

    }

  // Check accessibility, if required.

  if (! (Modifier::isPublic (meth->accflags) || this->isAccessible()))

    {

      Class *caller = _Jv_StackTrace::GetCallingClass (&Method::class$);

      if (! _Jv_CheckAccess(caller, declaringClass, meth->accflags))

        throw new IllegalAccessException;

    }

  if (declaringClass->isInterface())

    iface = declaringClass;

  return _Jv_CallAnyMethodA (obj, return_type, meth, false,

                             parameter_types, args, iface);

}

jint

java::lang::reflect::Method::getModifiers ()

{

  // Ignore all unknown flags.

  return _Jv_FromReflectedMethod (this)->accflags & Modifier::ALL_FLAGS;

}

jstring

java::lang::reflect::Method::getName ()

{

  if (name == NULL)

    name = _Jv_NewStringUtf8Const (_Jv_FromReflectedMethod (this)->name);

  return name;

}

/* Internal method to set return_type and parameter_types fields. */

void

java::lang::reflect::Method::getType ()

{

  _Jv_Method *method = _Jv_FromReflectedMethod (this);

  _Jv_GetTypesFromSignature (method,

                             declaringClass,

                             &parameter_types,

                             &return_type);

  int count = 0;

  if (method->throws != NULL)

    {

      while (method->throws[count] != NULL)

        ++count;

    }

  exception_types

    = (JArray<jclass> *) JvNewObjectArray (count, &java::lang::Class::class$,

                                           NULL);

  jclass *elts = elements (exception_types);

  for (int i = 0; i < count; ++i)

    elts[i] = _Jv_FindClass (method->throws[i],

                             declaringClass->getClassLoaderInternal ());

}

void

_Jv_GetTypesFromSignature (jmethodID method,

                           jclass declaringClass,

                           JArray<jclass> **arg_types_out,

                           jclass *return_type_out)

{

  _Jv_Utf8Const* sig = method->signature;

  java::lang::ClassLoader *loader = declaringClass->getClassLoaderInternal();

  char *ptr = sig->chars();

  int numArgs = 0;

  /* First just count the number of parameters. */

  // FIXME: should do some validation here, e.g., that there is only

  // one return type.

  for (; ; ptr++)

    {

      switch (*ptr)

        {

        case 0:

        case ')':

        case 'V':

          break;

        case '[':

        case '(':

          continue;

        case 'B':

        case 'C':

        case 'D':

        case 'F':

        case 'S':

        case 'I':

        case 'J':

        case 'Z':

          numArgs++;

          continue;

        case 'L':

          numArgs++;

          do

            ptr++;

          while (*ptr != ';' && ptr[1] != '\0');

          continue;

        }

      break;

    }

  JArray<jclass> *args = (JArray<jclass> *)

    JvNewObjectArray (numArgs, &java::lang::Class::class$, NULL);

  jclass* argPtr = elements (args);

  for (ptr = sig->chars(); *ptr != '\0'; ptr++)

    {

      if (*ptr == '(')

        continue;

      if (*ptr == ')')

        {

          argPtr = return_type_out;

          continue;

        }

      char *end_ptr;

      jclass type = _Jv_FindClassFromSignature (ptr, loader, &end_ptr);

      if (type == NULL)

        // FIXME: This isn't ideal.

        throw new java::lang::NoClassDefFoundError (sig->toString());

      // ARGPTR can be NULL if we are processing the return value of a

      // call from Constructor.

      if (argPtr)

        *argPtr++ = type;

      ptr = end_ptr;

    }

  *arg_types_out = args;

}

// This is a very rough analog of the JNI CallNonvirtual<type>MethodA

// functions.  It handles both Methods and Constructors, and it can

// handle any return type.  In the Constructor case, the `obj'

// argument is unused and should be NULL; also, the `return_type' is

// the class that the constructor will construct.  RESULT is a pointer

// to a `jvalue' (see jni.h); for a void method this should be NULL.

// This function returns an exception (if one was thrown), or NULL if

// the call went ok.

void

_Jv_CallAnyMethodA (jobject obj,

                    jclass return_type,

                    jmethodID meth,

                    jboolean is_constructor,

                    jboolean is_virtual_call,

                    JArray<jclass> *parameter_types,

                    jvalue *args,

                    jvalue *result,

                    jboolean is_jni_call,

                    jclass iface)

{

  using namespace java::lang::reflect;

#ifdef USE_LIBFFI

  JvAssert (! is_constructor || ! obj);

  JvAssert (! is_constructor || return_type);

  // See whether call needs an object as the first argument.  A

  // constructor does need a `this' argument, but it is one we create.

  jboolean needs_this = false;

  if (is_constructor

      || ! Modifier::isStatic(meth->accflags))

    needs_this = true;

  int param_count = parameter_types->length;

  if (needs_this)

    ++param_count;

  ffi_type *rtype;

  // A constructor itself always returns void.

  if (is_constructor || return_type == JvPrimClass (void))

    rtype = &ffi_type_void;

  else

    rtype = get_ffi_type (return_type);

  ffi_type **argtypes = (ffi_type **) __builtin_alloca (param_count

                                                        * sizeof (ffi_type *));

  jclass *paramelts = elements (parameter_types);

  // Special case for the `this' argument of a constructor.  Note that

  // the JDK 1.2 docs specify that the new object must be allocated

  // before argument conversions are done.

  if (is_constructor)

    obj = _Jv_AllocObject (return_type);

  const int size_per_arg = sizeof(jvalue);

  ffi_cif cif;

  char *p = (char *) __builtin_alloca (param_count * size_per_arg);

                // Overallocate to get correct alignment.

  void **values = (void **)

                        __builtin_alloca (param_count * sizeof (void *));

  int i = 0;

  if (needs_this)

    {

      // The `NULL' type is `Object'.

      argtypes[i] = get_ffi_type (NULL);

      values[i] = p;

      memcpy (p, &obj, sizeof (jobject));

      p += size_per_arg;

      ++i;

    }

  for (int arg = 0; i < param_count; ++i, ++arg)

    {

      int tsize;

      argtypes[i] = get_ffi_type (paramelts[arg]);

      if (paramelts[arg]->isPrimitive())

        tsize = paramelts[arg]->size();

      else

        tsize = sizeof (jobject);

      // Copy appropriate bits from the jvalue into the ffi array.

      // FIXME: we could do this copying all in one loop, above, by

      // over-allocating a bit.

      // How do we do this without breaking big-endian platforms?

      values[i] = p;

      memcpy (p, &args[arg], tsize);

      p += size_per_arg;

    }

  if (ffi_prep_cif (&cif, FFI_DEFAULT_ABI, param_count,

                    rtype, argtypes) != FFI_OK)

    throw new java::lang::VirtualMachineError(JvNewStringLatin1("internal error: ffi_prep_cif failed"));

  using namespace java::lang;

  using namespace java::lang::reflect;

  union

  {

    ffi_arg i;

    jobject o;

    jlong l;

    jfloat f;

    jdouble d;

  } ffi_result;

  switch (rtype->type)

    {

    case FFI_TYPE_VOID:

      break;

    case FFI_TYPE_SINT8:

      result->b = 0;

      break;

    case FFI_TYPE_SINT16:

      result->s = 0;

      break;

    case FFI_TYPE_UINT16:

      result->c = 0;

      break;

    case FFI_TYPE_SINT32:

      result->i = 0;

      break;

    case FFI_TYPE_SINT64:

      result->j = 0;

      break;

    case FFI_TYPE_FLOAT:

      result->f = 0;

      break;

    case FFI_TYPE_DOUBLE:

      result->d = 0;

      break;

    case FFI_TYPE_POINTER:

      result->l = 0;

      break;

    default:

      JvFail ("Unknown ffi_call return type");

      break;

    }

  void *ncode;

  // FIXME: If a vtable index is -1 at this point it is invalid, so we

  // have to use the ncode.  

  //

  // This can happen because methods in final classes don't have

  // vtable entries, but _Jv_isVirtualMethod() doesn't know that.  We

  // could solve this problem by allocating a vtable index for methods

  // in final classes.

  if (is_virtual_call

      && ! Modifier::isFinal (meth->accflags)

      && (_Jv_ushort)-1 != meth->index)

    {

      _Jv_VTable *vtable = *(_Jv_VTable **) obj;

      if (iface == NULL)

        {

          if (is_jni_call && Modifier::isAbstract (meth->accflags))

            {

              // With JNI we don't know if this is an interface call

              // or a call to an abstract method.  Look up the method

              // by name, the slow way.

              _Jv_Method *concrete_meth

                = _Jv_LookupDeclaredMethod (vtable->clas,

                                            meth->name,

                                            meth->signature,

                                            NULL);

              if (concrete_meth == NULL

                  || concrete_meth->ncode == NULL

                  || Modifier::isAbstract(concrete_meth->accflags))

                throw new java::lang::IncompatibleClassChangeError

                  (_Jv_GetMethodString (vtable->clas, meth));

              ncode = concrete_meth->ncode;

            }

          else

            ncode = vtable->get_method (meth->index);

        }

      else

        ncode = _Jv_LookupInterfaceMethodIdx (vtable->clas, iface,

                                              meth->index);

    }

  else

    {

      ncode = meth->ncode;

    }

  try

    {

      ffi_call (&cif, (void (*)()) ncode, &ffi_result, values);

    }

  catch (Throwable *ex)

    {

      // For JNI we just throw the real error.  For reflection, we

      // wrap the underlying method's exception in an

      // InvocationTargetException.

      if (! is_jni_call)

        ex = new InvocationTargetException (ex);

      throw ex;

    }

  // Since ffi_call returns integer values promoted to a word, use

  // a narrowing conversion for jbyte, jchar, etc. results.

  // Note that boolean is handled either by the FFI_TYPE_SINT8 or

  // FFI_TYPE_SINT32 case.

  if (is_constructor)

    result->l = obj;

  else

    {

      switch (rtype->type)

        {

        case FFI_TYPE_VOID:

          break;

        case FFI_TYPE_SINT8:

          result->b = (jbyte)ffi_result.i;

          break;

        case FFI_TYPE_SINT16:

          result->s = (jshort)ffi_result.i;

          break;

        case FFI_TYPE_UINT16:

          result->c = (jchar)ffi_result.i;

          break;

        case FFI_TYPE_SINT32:

          result->i = (jint)ffi_result.i;

          break;

        case FFI_TYPE_SINT64:

          result->j = (jlong)ffi_result.l;

          break;

        case FFI_TYPE_FLOAT:

          result->f = (jfloat)ffi_result.f;

          break;

        case FFI_TYPE_DOUBLE:

          result->d = (jdouble)ffi_result.d;

          break;

        case FFI_TYPE_POINTER:

          result->l = (jobject)ffi_result.o;

          break;

        default:

          JvFail ("Unknown ffi_call return type");

          break;

        }

    }

#else

  throw new java::lang::UnsupportedOperationException(JvNewStringLatin1("reflection not available in this build"));

#endif // USE_LIBFFI

}

// This is another version of _Jv_CallAnyMethodA, but this one does

// more checking and is used by the reflection (and not JNI) code.

jobject

_Jv_CallAnyMethodA (jobject obj,

                    jclass return_type,

                    jmethodID meth,

                    jboolean is_constructor,

                    JArray<jclass> *parameter_types,

                    jobjectArray args,

                    jclass iface)

{

  if (parameter_types->length == 0 && args == NULL)

    {

      // The JDK accepts this, so we do too.

    }

  else if (parameter_types->length != args->length)

    throw new java::lang::IllegalArgumentException;

  int param_count = parameter_types->length;

  jclass *paramelts = elements (parameter_types);

  jobject *argelts = args == NULL ? NULL : elements (args);

  jvalue argvals[param_count];

#define COPY(Where, What, Type) \

  do { \

    Type val = (What); \

    memcpy ((Where), &val, sizeof (Type)); \

  } while (0)

  for (int i = 0; i < param_count; ++i)

    {

      jclass k = argelts[i] ? argelts[i]->getClass() : NULL;

      if (paramelts[i]->isPrimitive())

        {

          if (! argelts[i]

              || ! k

              || ! can_widen (k, paramelts[i]))

            throw new java::lang::IllegalArgumentException;

          if (paramelts[i] == JvPrimClass (boolean))

            COPY (&argvals[i],

                  ((java::lang::Boolean *) argelts[i])->booleanValue(),

                  jboolean);

          else if (paramelts[i] == JvPrimClass (char))

            COPY (&argvals[i],

                  ((java::lang::Character *) argelts[i])->charValue(),

                  jchar);

          else

            {

              java::lang::Number *num = (java::lang::Number *) argelts[i];

              if (paramelts[i] == JvPrimClass (byte))

                COPY (&argvals[i], num->byteValue(), jbyte);

              else if (paramelts[i] == JvPrimClass (short))

                COPY (&argvals[i], num->shortValue(), jshort);

              else if (paramelts[i] == JvPrimClass (int))

                COPY (&argvals[i], num->intValue(), jint);

              else if (paramelts[i] == JvPrimClass (long))

                COPY (&argvals[i], num->longValue(), jlong);

              else if (paramelts[i] == JvPrimClass (float))

                COPY (&argvals[i], num->floatValue(), jfloat);

              else if (paramelts[i] == JvPrimClass (double))

                COPY (&argvals[i], num->doubleValue(), jdouble);

            }

        }

      else

        {

          if (argelts[i] && ! paramelts[i]->isAssignableFrom (k))

            throw new java::lang::IllegalArgumentException;

          COPY (&argvals[i], argelts[i], jobject);

        }

    }

  jvalue ret_value;

  _Jv_CallAnyMethodA (obj, return_type, meth, is_constructor,

                      _Jv_isVirtualMethod (meth),

                      parameter_types, argvals, &ret_value,

                      false, iface);

  jobject r;

#define VAL(Wrapper, Field)  (new Wrapper (ret_value.Field))

  if (is_constructor)

    r = ret_value.l;

  else  if (return_type == JvPrimClass (byte))

    r = VAL (java::lang::Byte, b);

  else if (return_type == JvPrimClass (short))

    r = VAL (java::lang::Short, s);

  else if (return_type == JvPrimClass (int))

    r = VAL (java::lang::Integer, i);

  else if (return_type == JvPrimClass (long))

    r = VAL (java::lang::Long, j);

  else if (return_type == JvPrimClass (float))

    r = VAL (java::lang::Float, f);

  else if (return_type == JvPrimClass (double))

    r = VAL (java::lang::Double, d);

  else if (return_type == JvPrimClass (boolean))

    r = VAL (java::lang::Boolean, z);