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jsj_method.c

/* -*- Mode: C; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 4 -*-
 *
 * ***** BEGIN LICENSE BLOCK *****
 * Version: MPL 1.1/GPL 2.0/LGPL 2.1
 *
 * The contents of this file are subject to the Mozilla Public License Version
 * 1.1 (the "License"); you may not use this file except in compliance with
 * the License. You may obtain a copy of the License at
 * http://www.mozilla.org/MPL/
 *
 * Software distributed under the License is distributed on an "AS IS" basis,
 * WITHOUT WARRANTY OF ANY KIND, either express or implied. See the License
 * for the specific language governing rights and limitations under the
 * License.
 *
 * The Original Code is Mozilla Communicator client code, released
 * March 31, 1998.
 *
 * The Initial Developer of the Original Code is
 * Netscape Communications Corporation.
 * Portions created by the Initial Developer are Copyright (C) 1998
 * the Initial Developer. All Rights Reserved.
 *
 * Contributor(s):
 *
 * Alternatively, the contents of this file may be used under the terms of
 * either of the GNU General Public License Version 2 or later (the "GPL"),
 * or the GNU Lesser General Public License Version 2.1 or later (the "LGPL"),
 * in which case the provisions of the GPL or the LGPL are applicable instead
 * of those above. If you wish to allow use of your version of this file only
 * under the terms of either the GPL or the LGPL, and not to allow others to
 * use your version of this file under the terms of the MPL, indicate your
 * decision by deleting the provisions above and replace them with the notice
 * and other provisions required by the GPL or the LGPL. If you do not delete
 * the provisions above, a recipient may use your version of this file under
 * the terms of any one of the MPL, the GPL or the LGPL.
 *
 * This Original Code has been modified by IBM Corporation. Modifications made
 * by IBM described herein are Copyright (c) International Business Machines
 * Corporation, 2000.
 * Modifications to Mozilla code or documentation identified per MPL Section 3.3
 *
 * Date             Modified by     Description of modification
 * 04/20/2000       IBM Corp.      OS/2 VisualAge build.
 *
 * ***** END LICENSE BLOCK ***** */

/*
 * This file is part of the Java-vendor-neutral implementation of LiveConnect
 *
 * It contains the code used to reflect Java methods as properties of
 * JavaObject objects and the code to invoke those methods.
 *
 */

#include <stdlib.h>
#include <string.h>

#include "jsj_private.h"        /* LiveConnect internals */
#include "jsjava.h"             /* LiveConnect external API */
#include "jsclist.h"            /* Circular linked lists */

/* A list of Java methods */
typedef JSCList MethodList;

/* An element in a list of Java methods */
typedef struct MethodListElement {
    JSCList linkage;
    JavaMethodSpec *method;
} MethodListElement;

/*
 * This is the return value of functions which compare either two types or two
 * method signatures to see if either is "preferred" when converting from
 * specified JavaScript value(s).
 */
typedef enum JSJTypePreference {
    JSJPREF_FIRST_ARG  = 1,       /* First argument preferred */
    JSJPREF_SECOND_ARG = 2,       /* Second argument preferred */
    JSJPREF_AMBIGUOUS  = 3        /* Neither preferred over the other */
} JSJTypePreference;

/*
 * Classification of JS types with slightly different granularity than JSType.
 * This is used to resolve among overloaded Java methods.
 */
typedef enum JSJType {
    JSJTYPE_VOID,                /* undefined */
    JSJTYPE_BOOLEAN,             /* boolean */
    JSJTYPE_NUMBER,              /* number */
    JSJTYPE_STRING,              /* string */
    JSJTYPE_NULL,                /* null */
    JSJTYPE_JAVACLASS,           /* JavaClass */
    JSJTYPE_JAVAOBJECT,          /* JavaObject */
    JSJTYPE_JAVAARRAY,         /* JavaArray */
    JSJTYPE_JSARRAY,             /* JS Array */
    JSJTYPE_OBJECT,              /* Any other JS Object, including functions */
    JSJTYPE_LIMIT
} JSJType;

/*
 * A helper function for jsj_ConvertJavaMethodSignatureToString():
 * Compute JNI-style (string) signatures for an array of JavaSignature objects
 * and concatenate the results into a single string.
 *
 * If an error is encountered, NULL is returned and the error reporter is called.
 */
static const char *
convert_java_method_arg_signatures_to_string(JSContext *cx,
                                             JavaSignature **arg_signatures,
                                             int num_args)
{
    const char *first_arg_signature, *rest_arg_signatures, *sig;
    JavaSignature **rest_args;

    /* Convert the first method argument in the array to a string */
    first_arg_signature = jsj_ConvertJavaSignatureToString(cx, arg_signatures[0]);
    if (!first_arg_signature)
        return NULL;

    /* If this is the last method argument in the array, we're done. */
    if (num_args == 1)
        return first_arg_signature;

    /* Convert the remaining method arguments to a string */
    rest_args = &arg_signatures[1];
    rest_arg_signatures =
        convert_java_method_arg_signatures_to_string(cx, rest_args, num_args - 1);
    if (!rest_arg_signatures) {
        JS_smprintf_free((char*)first_arg_signature);
        return NULL;
    }

    /* Concatenate the signature string of this argument with the signature
       strings of all the remaining arguments. */
    sig = JS_smprintf("%s%s", first_arg_signature, rest_arg_signatures);
    JS_smprintf_free((char*)first_arg_signature);
    JS_smprintf_free((char*)rest_arg_signatures);
    if (!sig) {
        JS_ReportOutOfMemory(cx);
        return NULL;
    }

    return sig;
}

/*
 * A helper function for jsj_ConvertJavaMethodSignatureToHRString():
 * Compute human-readable string signatures for an array of JavaSignatures
 * and concatenate the results into a single string.
 *
 * If an error is encountered, NULL is returned and the error reporter is called.
 */
static const char *
convert_java_method_arg_signatures_to_hr_string(JSContext *cx,
                                                JavaSignature **arg_signatures,
                                                int num_args,
                                    JSBool whitespace)
{
    const char *first_arg_signature, *rest_arg_signatures, *sig, *separator;
    JavaSignature **rest_args;

    if (num_args == 0)
        return JS_smprintf("%s", "");

    /* Convert the first method argument in the array to a string */
    first_arg_signature = jsj_ConvertJavaSignatureToHRString(cx, arg_signatures[0]);
    if (!first_arg_signature)
        return NULL;

    /* If this is the last method argument in the array, we're done. */
    if (num_args == 1)
        return first_arg_signature;

    /* Convert the remaining method arguments to a string */
    rest_args = &arg_signatures[1];
    rest_arg_signatures =
        convert_java_method_arg_signatures_to_hr_string(cx, rest_args, num_args - 1, whitespace);
    if (!rest_arg_signatures) {
        JS_smprintf_free((char*)first_arg_signature);
        return NULL;
    }

    /* Concatenate the signature string of this argument with the signature
       strings of all the remaining arguments. */
    separator = whitespace ? " " : "";
    sig = JS_smprintf("%s,%s%s", first_arg_signature, separator, rest_arg_signatures);
    JS_smprintf_free((char*)first_arg_signature);
    JS_smprintf_free((char*)rest_arg_signatures);
    if (!sig) {
        JS_ReportOutOfMemory(cx);
        return NULL;
    }

    return sig;
}
/*
 * Compute a string signature for the given method using the same type names
 * that appear in Java source files, e.g. "int[][]", rather than the JNI-style
 * type strings that are provided by the functions above.  An example return
 * value might be "String MyFunc(int, byte, char[][], java.lang.String)".
 *
 * If an error is encountered, NULL is returned and the error reporter is called.
 */
const char *
jsj_ConvertJavaMethodSignatureToHRString(JSContext *cx,
                                         const char *method_name,
                                         JavaMethodSignature *method_signature)
{
    JavaSignature **arg_signatures, *return_val_signature;
    const char *arg_sigs_cstr;
    const char *return_val_sig_cstr;
    const char *sig_cstr;

    arg_signatures = method_signature->arg_signatures;
    return_val_signature = method_signature->return_val_signature;

    /* Convert the method argument signatures to a C-string */
    arg_sigs_cstr =
            convert_java_method_arg_signatures_to_hr_string(cx, arg_signatures,
                                                            method_signature->num_args,
                                              JS_TRUE);
    if (!arg_sigs_cstr)
        return NULL;

    /* Convert the method return value signature to a C-string */
    return_val_sig_cstr = jsj_ConvertJavaSignatureToHRString(cx, return_val_signature);
    if (!return_val_sig_cstr) {
        JS_smprintf_free((char*)arg_sigs_cstr);
        return NULL;
    }

    /* Compose method arg signatures string and return val signature string */
    sig_cstr = JS_smprintf("%s %s(%s)", return_val_sig_cstr, method_name, arg_sigs_cstr);
    JS_smprintf_free((char*)arg_sigs_cstr);
    JS_smprintf_free((char*)return_val_sig_cstr);

    if (!sig_cstr) {
        JS_ReportOutOfMemory(cx);
        return NULL;
    }
    return sig_cstr;
}
/*
 * Destroy the sub-structure of a JavaMethodSignature object without free'ing
 * the method signature itself.
 */
void
jsj_PurgeJavaMethodSignature(JSContext *cx, JNIEnv *jEnv, JavaMethodSignature *method_signature)
{
    int i, num_args;
    JavaSignature **arg_signatures;

    if (!method_signature)  /* Paranoia */
        return;

    /* Free the method argument signatures */
    num_args = method_signature->num_args;
    arg_signatures = method_signature->arg_signatures;
    for (i = 0; i < num_args; i++)
        jsj_ReleaseJavaClassDescriptor(cx, jEnv, arg_signatures[i]);
    if (arg_signatures)
        JS_free(cx, arg_signatures);

    /* Free the return type signature */
    if (method_signature->return_val_signature)
        jsj_ReleaseJavaClassDescriptor(cx, jEnv, method_signature->return_val_signature);
}

/*
 * Fill in the members of a JavaMethodSignature object using the method
 * argument, which can be either an instance of either java.lang.reflect.Method
 * or java.lang.reflect.Constructor.
 *
 * With normal completion, return the original method_signature argument.
 * If an error occurs, return NULL and call the error reporter.
 */
JavaMethodSignature *
jsj_InitJavaMethodSignature(JSContext *cx, JNIEnv *jEnv,
                           jobject method,
                           JavaMethodSignature *method_signature)
{
    int i;
    jboolean is_constructor;
    jclass return_val_class;
    jsize num_args;
    JavaSignature *return_val_signature;
    jarray arg_classes;
    jmethodID getParameterTypes;

    memset(method_signature, 0, sizeof (JavaMethodSignature));
    
    is_constructor = (*jEnv)->IsInstanceOf(jEnv, method, jlrConstructor);

    /* Get a Java array that lists the class of each of the method's arguments */
    if  (is_constructor)
        getParameterTypes = jlrConstructor_getParameterTypes;
    else
        getParameterTypes = jlrMethod_getParameterTypes;
    arg_classes = (*jEnv)->CallObjectMethod(jEnv, method, getParameterTypes);
    if (!arg_classes) {
        jsj_UnexpectedJavaError(cx, jEnv,
                                "Can't determine argument signature of method");
        goto error;
    }

    /* Compute the number of method arguments */
    num_args = jsj_GetJavaArrayLength(cx, jEnv, arg_classes);
    if (num_args < 0)
        goto error;
    method_signature->num_args = num_args;

    /* Build a JavaSignature array corresponding to the method's arguments */
    if (num_args) {
        JavaSignature **arg_signatures;

        /* Allocate an array of JavaSignatures, one for each method argument */
        size_t arg_signatures_size = num_args * sizeof(JavaSignature *);
        arg_signatures = (JavaSignature **)JS_malloc(cx, arg_signatures_size);
        if (!arg_signatures)
            goto error;
        memset(arg_signatures, 0, arg_signatures_size);
        method_signature->arg_signatures = arg_signatures;
        
        /* Build an array of JavaSignature objects, each of which corresponds
           to the type of an individual method argument. */
        for (i = 0; i < num_args; i++) {
            JavaSignature *a;
            jclass arg_class = (*jEnv)->GetObjectArrayElement(jEnv, arg_classes, i);
            
            a = arg_signatures[i] = jsj_GetJavaClassDescriptor(cx, jEnv, arg_class);
            (*jEnv)->DeleteLocalRef(jEnv, arg_class);
            if (!a) {
                jsj_UnexpectedJavaError(cx, jEnv, "Could not determine Java class "
                                                  "signature using java.lang.reflect");
                goto error;
            }
        }
    }

    /* Get the Java class of the method's return value */
    if (is_constructor) {
        /* Constructors always have a "void" return type */
        return_val_signature = jsj_GetJavaClassDescriptor(cx, jEnv, jlVoid_TYPE);
    } else {
        return_val_class =
            (*jEnv)->CallObjectMethod(jEnv, method, jlrMethod_getReturnType);
        if (!return_val_class) {
            jsj_UnexpectedJavaError(cx, jEnv,
                                    "Can't determine return type of method "
                                    "using java.lang.reflect.Method.getReturnType()");
            goto error;
        }

        /* Build a JavaSignature object corresponding to the method's return value */
        return_val_signature = jsj_GetJavaClassDescriptor(cx, jEnv, return_val_class);
        (*jEnv)->DeleteLocalRef(jEnv, return_val_class);
    }

    if (!return_val_signature)
        goto error;
    method_signature->return_val_signature = return_val_signature;

    (*jEnv)->DeleteLocalRef(jEnv, arg_classes);
    return method_signature;

error:

    if (arg_classes)
        (*jEnv)->DeleteLocalRef(jEnv, arg_classes);
    jsj_PurgeJavaMethodSignature(cx, jEnv, method_signature);
    return NULL;
}

/*
 * Compute a JNI-style (string) signature for the given method, e.g. the method
 * "String MyFunc(int, byte)" is translated to "(IB)Ljava/lang/String;".
 *
 * If an error is encountered, NULL is returned and the error reporter is called.
 */
const char *
jsj_ConvertJavaMethodSignatureToString(JSContext *cx,
                                       JavaMethodSignature *method_signature)
{
    JavaSignature **arg_signatures, *return_val_signature;
    const char *arg_sigs_cstr;
    const char *return_val_sig_cstr;
    const char *sig_cstr;

    arg_signatures = method_signature->arg_signatures;
    return_val_signature = method_signature->return_val_signature;

    /* Convert the method argument signatures to a C-string */
    arg_sigs_cstr = NULL;
    if (arg_signatures) {
        arg_sigs_cstr =
            convert_java_method_arg_signatures_to_string(cx, arg_signatures,
                                                         method_signature->num_args);
        if (!arg_sigs_cstr)
            return NULL;
    }

    /* Convert the method return value signature to a C-string */
    return_val_sig_cstr = jsj_ConvertJavaSignatureToString(cx, return_val_signature);
    if (!return_val_sig_cstr) {
        JS_smprintf_free((char*)arg_sigs_cstr);
        return NULL;
    }

    /* Compose method arg signatures string and return val signature string */
    if (arg_sigs_cstr) {
        sig_cstr = JS_smprintf("(%s)%s", arg_sigs_cstr, return_val_sig_cstr);
        JS_smprintf_free((char*)arg_sigs_cstr);
    } else {
        sig_cstr = JS_smprintf("()%s", return_val_sig_cstr);
    }

    JS_smprintf_free((char*)return_val_sig_cstr);

    if (!sig_cstr) {
        JS_ReportOutOfMemory(cx);
        return NULL;
    }
    return sig_cstr;
}

static JSBool
add_java_method_to_class_descriptor(JSContext *cx, JNIEnv *jEnv,
                                    JavaClassDescriptor *class_descriptor, 
                                    jstring method_name_jstr,
                                    jobject java_method,
                                    JSBool is_static_method,
                                    JSBool is_constructor)
{
    jmethodID methodID;
    JSFunction *fun;
    jclass java_class = class_descriptor->java_class;

    JavaMemberDescriptor *member_descriptor = NULL;
    const char *sig_cstr = NULL;
    const char *method_name = NULL;
    JavaMethodSignature *signature = NULL;
    JavaMethodSpec **specp, *method_spec = NULL;
            
    if (is_constructor) {
        member_descriptor = jsj_GetJavaClassConstructors(cx, class_descriptor);
    } else {
        if (is_static_method) {
            member_descriptor = jsj_GetJavaStaticMemberDescriptor(cx, jEnv, class_descriptor, method_name_jstr);
        } else {
            member_descriptor = jsj_GetJavaMemberDescriptor(cx, jEnv, class_descriptor, method_name_jstr);
      }
        fun = JS_NewFunction(cx, jsj_JavaInstanceMethodWrapper, 0,
                           JSFUN_BOUND_METHOD, NULL, member_descriptor->name);
      member_descriptor->invoke_func_obj = JS_GetFunctionObject(fun);
        JS_AddNamedRoot(cx, &member_descriptor->invoke_func_obj,
                        "&member_descriptor->invoke_func_obj");
    }
    if (!member_descriptor)
        return JS_FALSE;
    
    method_spec = (JavaMethodSpec*)JS_malloc(cx, sizeof(JavaMethodSpec));
    if (!method_spec)
        goto error;
    memset(method_spec, 0, sizeof(JavaMethodSpec));

    signature = jsj_InitJavaMethodSignature(cx, jEnv, java_method, &method_spec->signature);
    if (!signature)
        goto error;

    method_name = JS_strdup(cx, member_descriptor->name);
    if (!method_name)
        goto error;
    method_spec->name = method_name;
    
    sig_cstr = jsj_ConvertJavaMethodSignatureToString(cx, signature);
    if (!sig_cstr)
        goto error;

    if (is_static_method)
        methodID = (*jEnv)->GetStaticMethodID(jEnv, java_class, method_name, sig_cstr);
    else
        methodID = (*jEnv)->GetMethodID(jEnv, java_class, method_name, sig_cstr);
    method_spec->methodID = methodID;
    
    if (!methodID) {
        jsj_UnexpectedJavaError(cx, jEnv,
                                "Can't get Java method ID for %s.%s() (sig=%s)",
                                class_descriptor->name, method_name, sig_cstr);
        goto error;
    }
    
    JS_free(cx, (char*)sig_cstr);

    /* Add method to end of list of overloaded methods for this class member */ 
    specp = &member_descriptor->methods;
    while (*specp) {
        specp = &(*specp)->next;
    }
    *specp = method_spec;

    return JS_TRUE;

error:
    if (method_spec)
        JS_FREE_IF(cx, (char*)method_spec->name);
    JS_FREE_IF(cx, (char*)sig_cstr);
    if (signature)
        jsj_PurgeJavaMethodSignature(cx, jEnv, signature);
    JS_FREE_IF(cx, method_spec);
    return JS_FALSE;
}

JSBool 
jsj_ReflectJavaMethods(JSContext *cx, JNIEnv *jEnv,
                       JavaClassDescriptor *class_descriptor,
                       JSBool reflect_only_static_methods)
{
    jarray joMethodArray, joConstructorArray;
    jsize num_methods, num_constructors;
    int i;
    jclass java_class;
    JSBool ok, reflect_only_instance_methods;

    reflect_only_instance_methods = !reflect_only_static_methods;

    /* Get a java array of java.lang.reflect.Method objects, by calling
       java.lang.Class.getMethods(). */
    java_class = class_descriptor->java_class;
    joMethodArray = (*jEnv)->CallObjectMethod(jEnv, java_class, jlClass_getMethods);
    if (!joMethodArray) {
        jsj_UnexpectedJavaError(cx, jEnv,
                                "Can't determine Java object's methods "
                                "using java.lang.Class.getMethods()");
        return JS_FALSE;
    }

    /* Iterate over the class methods */
    num_methods = (*jEnv)->GetArrayLength(jEnv, joMethodArray);
    for (i = 0; i < num_methods; i++) {
        jstring method_name_jstr;
        
        /* Get the i'th reflected method */
        jobject java_method = (*jEnv)->GetObjectArrayElement(jEnv, joMethodArray, i);

        /* Get the method modifiers, eg static, public, private, etc. */
        jint modifiers = (*jEnv)->CallIntMethod(jEnv, java_method, jlrMethod_getModifiers);

        /* Don't allow access to private or protected Java methods. */
        if (!(modifiers & ACC_PUBLIC))
            goto dont_reflect_method;

        /* Abstract methods can't be invoked */
        if (modifiers & ACC_ABSTRACT)
            goto dont_reflect_method;

        /* Reflect all instance methods or all static methods, but not both */
        if (reflect_only_static_methods != ((modifiers & ACC_STATIC) != 0))
            goto dont_reflect_method;
        
        /* Add a JavaMethodSpec object to the JavaClassDescriptor */
        method_name_jstr = (*jEnv)->CallObjectMethod(jEnv, java_method, jlrMethod_getName);
        ok = add_java_method_to_class_descriptor(cx, jEnv, class_descriptor, method_name_jstr, java_method,
                                                 reflect_only_static_methods, JS_FALSE);
        (*jEnv)->DeleteLocalRef(jEnv, method_name_jstr);
        if (!ok) {
            (*jEnv)->DeleteLocalRef(jEnv, java_method);
            (*jEnv)->DeleteLocalRef(jEnv, joMethodArray);
            return JS_FALSE;
        }

dont_reflect_method:
        (*jEnv)->DeleteLocalRef(jEnv, java_method);
    }

    (*jEnv)->DeleteLocalRef(jEnv, joMethodArray);
    if (reflect_only_instance_methods)
        return JS_TRUE;
        
    joConstructorArray = (*jEnv)->CallObjectMethod(jEnv, java_class, jlClass_getConstructors);
    if (!joConstructorArray) {
        jsj_UnexpectedJavaError(cx, jEnv, "internal error: "
                                "Can't determine Java class's constructors "
                                "using java.lang.Class.getConstructors()");
        return JS_FALSE;
    }

    /* Iterate over the class constructors */
    num_constructors = (*jEnv)->GetArrayLength(jEnv, joConstructorArray);
    for (i = 0; i < num_constructors; i++) {
        /* Get the i'th reflected constructor */
        jobject java_constructor =
            (*jEnv)->GetObjectArrayElement(jEnv, joConstructorArray, i);

        /* Get the method modifiers, eg public, private, etc. */
        jint modifiers = (*jEnv)->CallIntMethod(jEnv, java_constructor,
                                                jlrConstructor_getModifiers);

        /* Don't allow access to private or protected Java methods. */
        if (!(modifiers & ACC_PUBLIC))
            goto dont_reflect_constructor;
        
        /* Add a JavaMethodSpec object to the JavaClassDescriptor */
        ok = add_java_method_to_class_descriptor(cx, jEnv, class_descriptor, NULL,
                                                 java_constructor,
                                                 JS_FALSE, JS_TRUE);
        if (!ok) {
            (*jEnv)->DeleteLocalRef(jEnv, joConstructorArray);
            (*jEnv)->DeleteLocalRef(jEnv, java_constructor);
            return JS_FALSE;
        }

dont_reflect_constructor:
        (*jEnv)->DeleteLocalRef(jEnv, java_constructor);
    }

    (*jEnv)->DeleteLocalRef(jEnv, joConstructorArray);
    return JS_TRUE;
}

/*
 * Free up a JavaMethodSpec and all its resources.
 */
void
jsj_DestroyMethodSpec(JSContext *cx, JNIEnv *jEnv, JavaMethodSpec *method_spec)
{
    if (!method_spec->is_alias) {
      JS_FREE_IF(cx, (char*)method_spec->name);
      jsj_PurgeJavaMethodSignature(cx, jEnv, &method_spec->signature);
    }
    JS_free(cx, method_spec);
}

static JavaMethodSpec *
copy_java_method_descriptor(JSContext *cx, JavaMethodSpec *method)
{
    JavaMethodSpec *copy;

    copy = (JavaMethodSpec*)JS_malloc(cx, sizeof(JavaMethodSpec));
    if (!copy)
        return NULL;
    memcpy(copy, method, sizeof(JavaMethodSpec));
    copy->next = NULL;
    copy->is_alias = JS_TRUE;
    return copy;
}

/*
 * See if a reference to a JavaObject/JavaClass's property looks like the
 * explicit resolution of an overloaded method, e.g. 
 * java.lang.String["max(double,double)"].  If so, add a new member
 * (JavaMemberDescriptor) to the object that is an alias for the resolved
 * method.
 */
JavaMemberDescriptor *
jsj_ResolveExplicitMethod(JSContext *cx, JNIEnv *jEnv,
                    JavaClassDescriptor *class_descriptor, 
                    jsid method_name_id,
                    JSBool is_static)
{
    JavaMethodSpec *method;
    JavaMemberDescriptor *member_descriptor;
    JavaMethodSignature *ms;
    JSString *simple_name_jsstr;
    JSFunction *fun;
    JSBool is_constructor;
    int left_paren;
    const char *sig_cstr, *method_name;
    char *arg_start;
    jsid id;
    jsval method_name_jsval;
      
    /*
     * Get the simple name of the explicit method, i.e. get "cos" from
     * "cos(double)", and use it to create a new JS string.
     */
    JS_IdToValue(cx, method_name_id, &method_name_jsval);
    method_name = JS_GetStringBytes(JSVAL_TO_STRING(method_name_jsval));
    arg_start = strchr(method_name, '('); /* Skip until '(' */
    /* If no left-paren, then this is not a case of explicit method resolution */
    if (!arg_start)
      return NULL;
    /* Left-paren must be first character for constructors */
    is_constructor = (is_static && (arg_start == method_name));
        
    left_paren = arg_start - method_name;
    simple_name_jsstr = JS_NewStringCopyN(cx, method_name, left_paren);
    if (!simple_name_jsstr)
      return NULL;

    /* Find all the methods in the same class with the same simple name */
    JS_ValueToId(cx, STRING_TO_JSVAL(simple_name_jsstr), &id);
    if (is_constructor)
        member_descriptor = jsj_LookupJavaClassConstructors(cx, jEnv, class_descriptor);
    else if (is_static)
      member_descriptor = jsj_LookupJavaStaticMemberDescriptorById(cx, jEnv, class_descriptor, id);
    else
      member_descriptor = jsj_LookupJavaMemberDescriptorById(cx, jEnv, class_descriptor, id);
    if (!member_descriptor)   /* No member with matching simple name ? */
      return NULL;
    
    /*
     * Do a UTF8 comparison of method signatures with all methods of the same name,
     * so as to discover a method which exactly matches the specified argument types.
     */
    if (!strlen(arg_start + 1))
      return NULL;
    arg_start = JS_strdup(cx, arg_start + 1);
    if (!arg_start)
      return NULL;
    arg_start[strlen(arg_start) - 1] = '\0';    /* Get rid of ')' */
    sig_cstr = NULL;    /* Quiet gcc warning about uninitialized variable */
    for (method = member_descriptor->methods; method; method = method->next) {
      ms = &method->signature;
      sig_cstr = convert_java_method_arg_signatures_to_hr_string(cx, ms->arg_signatures,
                                                   ms->num_args, JS_FALSE);
      if (!sig_cstr) {
          JS_free(cx, arg_start);
          return NULL;
      }

      if (!strcmp(sig_cstr, arg_start))
          break;
      JS_smprintf_free((char*)sig_cstr);
    }
    JS_free(cx, arg_start);
    if (!method)
      return NULL;
    JS_smprintf_free((char*)sig_cstr);
    
    /* Don't bother doing anything if the method isn't overloaded */
    if (!member_descriptor->methods->next)
      return member_descriptor;

    /*
     * To speed up performance for future accesses, create a new member descriptor
     * with a name equal to the explicit method name, i.e. "cos(double)".
     */
    member_descriptor = JS_malloc(cx, sizeof(JavaMemberDescriptor));
    if (!member_descriptor)
        return NULL;
    memset(member_descriptor, 0, sizeof(JavaMemberDescriptor));

    member_descriptor->id = method_name_id;
    member_descriptor->name =
        JS_strdup(cx, is_constructor ? "<init>" : JS_GetStringBytes(simple_name_jsstr));
    if (!member_descriptor->name) {
        JS_free(cx, member_descriptor);
        return NULL;
    }

    member_descriptor->methods = copy_java_method_descriptor(cx, method);
    if (!member_descriptor->methods) {
      JS_free(cx, (void*)member_descriptor->name);
        JS_free(cx, member_descriptor);
        return NULL;
    }
 
    fun = JS_NewFunction(cx, jsj_JavaInstanceMethodWrapper, 0,
                   JSFUN_BOUND_METHOD, NULL, method_name);
    member_descriptor->invoke_func_obj = JS_GetFunctionObject(fun);
    JS_AddNamedRoot(cx, &member_descriptor->invoke_func_obj,
                    "&member_descriptor->invoke_func_obj");

    /* THREADSAFETY */
    /* Add the new aliased member to the list of all members for the class */
    if (is_static) {
      member_descriptor->next = class_descriptor->static_members;
      class_descriptor->static_members = member_descriptor;
    } else {
      member_descriptor->next = class_descriptor->instance_members;
      class_descriptor->instance_members = member_descriptor;
    }

    return member_descriptor;
}

/*
 * Return the JavaScript types that a JavaScript method was invoked with
 * as a string, e.g. a JS method invoked like foo(3, 'hey', 'you', true)
 * would cause a return value of "(number, string, string, boolean)".
 * The returned string must be free'ed by the caller.
 * Returns NULL and reports an error if out-of-memory.
 */
static const char *
get_js_arg_types_as_string(JSContext *cx, uintN argc, jsval *argv)
{
    uintN i;
    const char *arg_type, *arg_string, *tmp;

    if (argc == 0)
        return JS_smprintf("%s", "()");
    
    arg_string = strdup("(");
    if (!arg_string)
        goto out_of_memory;
    for (i = 0; i < argc; i++) {
        arg_type = JS_GetTypeName(cx, JS_TypeOfValue(cx, argv[i]));
        tmp = JS_smprintf("%s%s%s%s", arg_string,  i ? ", " : "", arg_type,
                         (i == argc-1) ? ")" : "");
        free((char*)arg_string);
        if (!tmp)
            goto out_of_memory;
        arg_string = tmp;
    }

    return arg_string;

out_of_memory:
    JS_ReportOutOfMemory(cx);
    return NULL;
}

/*
 * This is an error reporting routine used when a method of the correct name
 * and class exists but either the number of arguments is incorrect or the
 * arguments are of the wrong type.
 */
static void
report_method_match_failure(JSContext *cx,
                            JavaMemberDescriptor *member_descriptor,
                            JavaClassDescriptor *class_descriptor,
                            JSBool is_static_method,
                            uintN argc, jsval *argv)
{
    const char *err, *js_arg_string, *tmp, *method_str, *method_name;
    JSBool is_constructor;
    JavaMethodSpec *method;

    err = NULL;
    is_constructor = (!strcmp(member_descriptor->name, "<init>"));

    js_arg_string = get_js_arg_types_as_string(cx, argc, argv);
    if (!js_arg_string)
        goto out_of_memory;

    if (is_constructor) {
        err =  JS_smprintf("There is no Java constructor for class %s that matches "
                           "JavaScript argument types %s.\n", class_descriptor->name,
                           js_arg_string);
        method_name = class_descriptor->name;
    } else {
        err =  JS_smprintf("There is no %sJava method %s.%s that matches "
                           "JavaScript argument types %s.\n",
                           is_static_method ? "static ": "",
                           class_descriptor->name, member_descriptor->name, js_arg_string);
        method_name = member_descriptor->name;
    }
    if (!err)
        goto out_of_memory;

    tmp = JS_smprintf("%sCandidate methods with the same name are:\n", err);
    if (!tmp)
        goto out_of_memory;
    err = tmp;

    method = member_descriptor->methods;
    while (method) {
        method_str =
            jsj_ConvertJavaMethodSignatureToHRString(cx, method_name, &method->signature);
        if (!method_str)
            goto out_of_memory;
        tmp = JS_smprintf("%s   %s\n", err, method_str);
        JS_smprintf_free((char*)method_str);
        if (!tmp)
            goto out_of_memory;
        err = tmp;

        method = method->next;
    }
    
    JS_ReportError(cx, err);
    return;

out_of_memory:
    if (js_arg_string)
        JS_smprintf_free((char*)js_arg_string);
    if (err)
        JS_smprintf_free((char*)err);
}

/*
 * This is an error reporting routine used when a method of the correct name
 * and class exists but more than one Java method in a set of overloaded
 * methods are compatible with the JavaScript argument types and none of them
 * match any better than all the others.
 */
static void
report_ambiguous_method_match(JSContext *cx,
                              JavaMemberDescriptor *member_descriptor,
                              JavaClassDescriptor *class_descriptor,
                              MethodList *ambiguous_methods,
                              JSBool is_static_method,
                              uintN argc, jsval *argv)
{
    const char *err, *js_arg_string, *tmp, *method_str, *method_name;
    JSBool is_constructor;
    JavaMethodSpec *method;
    MethodListElement *method_list_element;

    err = NULL;
    is_constructor = (!strcmp(member_descriptor->name, "<init>"));

    js_arg_string = get_js_arg_types_as_string(cx, argc, argv);
    if (!js_arg_string)
        goto out_of_memory;

    if (is_constructor) {
        err =  JS_smprintf("The choice of Java constructor for class %s with "
                           "JavaScript argument types %s is ambiguous.\n",
                           class_descriptor->name,
                           js_arg_string);
        method_name = class_descriptor->name;
    } else {
        err =  JS_smprintf("The choice of %sJava method %s.%s matching "
                           "JavaScript argument types %s is ambiguous.\n",
                           is_static_method ? "static ": "",
                           class_descriptor->name, member_descriptor->name,
                           js_arg_string);
        method_name = member_descriptor->name;
    }
    if (!err)
        goto out_of_memory;

    tmp = JS_smprintf("%sCandidate methods are:\n", err);
    if (!tmp)
        goto out_of_memory;
    err = tmp;

    method_list_element = (MethodListElement*)JS_LIST_HEAD(ambiguous_methods);
    while ((MethodList*)method_list_element != ambiguous_methods) {
        method = method_list_element->method;
        method_str =
            jsj_ConvertJavaMethodSignatureToHRString(cx, method_name, &method->signature);
        if (!method_str)
            goto out_of_memory;
        tmp = JS_smprintf("%s   %s\n", err, method_str);
        JS_smprintf_free((char*)method_str);
        if (!tmp)
            goto out_of_memory;
        err = tmp;

        method_list_element = (MethodListElement*)method_list_element->linkage.next;
    }
    
    JS_ReportError(cx, err);
    return;

out_of_memory:
    if (js_arg_string)
        JS_smprintf_free((char*)js_arg_string);
    if (err)
        JS_smprintf_free((char*)err);
}

/*
 * Compute classification of JS types with slightly different granularity
 * than JSType.  This is used to resolve among overloaded Java methods.
 */
static JSJType
compute_jsj_type(JSContext *cx, jsval v)
{
    JSObject *js_obj;

    if (JSVAL_IS_OBJECT(v)) {
        if (JSVAL_IS_NULL(v))
            return JSJTYPE_NULL;
        js_obj = JSVAL_TO_OBJECT(v);
        if (JS_InstanceOf(cx, js_obj, &JavaObject_class, 0))
          return JSJTYPE_JAVAOBJECT;
        if (JS_InstanceOf(cx, js_obj, &JavaArray_class, 0))
            return JSJTYPE_JAVAARRAY;
        if (JS_InstanceOf(cx, js_obj, &JavaClass_class, 0))
            return JSJTYPE_JAVACLASS;
        if (JS_IsArrayObject(cx, js_obj))
            return JSJTYPE_JSARRAY;
        return JSJTYPE_OBJECT;
    } else if (JSVAL_IS_NUMBER(v)) {
      return JSJTYPE_NUMBER;
    } else if (JSVAL_IS_STRING(v)) {
      return JSJTYPE_STRING;
    } else if (JSVAL_IS_BOOLEAN(v)) {
      return JSJTYPE_BOOLEAN;
    } else if (JSVAL_IS_VOID(v)) {
      return JSJTYPE_VOID;
    }
    JS_ASSERT(0);   /* Unknown JS type ! */
    return JSJTYPE_VOID;
}

/* 
 * Ranking table used to establish preferences among Java types when converting
 * from JavaScript types.  Each row represents a different JavaScript source
 * type and each column represents a different target Java type.  Lower values
 * in the table indicate conversions that are ranked higher.  The special
 * value 99 indicates a disallowed JS->Java conversion.  The special value of
 * 0 indicates special handling is required to determine ranking.
 */
static int rank_table[JSJTYPE_LIMIT][JAVA_SIGNATURE_LIMIT] = {
/*    boolean             long
      |   char            |   float           java.lang.Boolean
      |   |   byte        |   |   double      |   java.lang.Class
      |   |   |   short   |   |   |   array   |   |   java.lang.Double
      |   |   |   |   int |   |   |   |   object  |   |   netscape.javascript.JSObject
      |   |   |   |   |   |   |   |   |   |   |   |   |   |   java.lang.Object
      |   |   |   |   |   |   |   |   |   |   |   |   |   |   |   java.lang.String */

    {99, 99, 99, 99, 99, 99, 99, 99, 99, 99, 99, 99, 99, 99,  1,  1}, /* undefined */
    { 1, 99, 99, 99, 99, 99, 99, 99, 99, 99,  2, 99, 99, 99,  3,  4}, /* boolean */
    {99,  7,  8,  6,  5,  4,  3,  1, 99, 99, 99, 99,  2, 99, 11,  9}, /* number */
    {99,  3,  4,  4,  4,  4,  4,  4, 99, 99, 99, 99, 99, 99,  2,  1}, /* string */
    {99, 99, 99, 99, 99, 99, 99, 99,  1,  1,  1,  1,  1,  1,  1,  1}, /* null */
    {99, 99, 99, 99, 99, 99, 99, 99, 99, 99, 99,  1, 99,  2,  3,  4}, /* JavaClass */
    {99,  7,  8,  6,  5,  4,  3,  2,  0,  0,  0,  0,  0,  0,  0,  1}, /* JavaObject */
    {99, 99, 99, 99, 99, 99, 99, 99,  0,  0, 99, 99, 99, 99,  0,  1}, /* JavaArray */
    {99, 99, 99, 99, 99, 99, 99, 99,  2, 99, 99, 99, 99,  1,  3,  4}, /* JS Array */
    {99,  9, 10,  8,  7,  6,  5,  4, 99, 99, 99, 99, 99,  1,  2,  3}  /* other JS object */
};

/*
 * Returns JS_TRUE if JavaScript arguments are compatible with the specified
 * Java method signature.
 */
static JSBool
method_signature_matches_JS_args(JSContext *cx, JNIEnv *jEnv, uintN argc, jsval *argv,
                                 JavaMethodSignature *method_signature)
{
    uintN i;
    JavaClassDescriptor *descriptor;
    JavaObjectWrapper *java_wrapper;
    jclass java_class;
    jobject java_obj;
    JSObject *js_obj;
    JSJType js_type;
    jsval js_val;
    int rank;

    if (argc != (uintN)method_signature->num_args)
        return JS_FALSE;

    for (i = 0; i < argc; i++) {
        js_val = argv[i];
        js_type = compute_jsj_type(cx, js_val);
        descriptor = method_signature->arg_signatures[i];
        rank = rank_table[js_type][(int)descriptor->type - 2];

        /* Check for disallowed JS->Java conversion */
        if (rank == 99)
            return JS_FALSE;

        /* Check for special handling required by conversion from JavaObject */
        if (rank == 0) {
            java_class = descriptor->java_class;
        
            js_obj = JSVAL_TO_OBJECT(js_val);
            java_wrapper = JS_GetPrivate(cx, js_obj);
            java_obj = java_wrapper->java_obj;
        
            if (!(*jEnv)->IsInstanceOf(jEnv, java_obj, java_class))
                return JS_FALSE;
        }
    }

    return JS_TRUE;
}

#ifdef HAS_OLD_STYLE_METHOD_RESOLUTION

static JavaMethodSpec *
resolve_overloaded_method(JSContext *cx, JNIEnv *jEnv, JavaMemberDescriptor *member_descriptor,
                          JavaClassDescriptor *class_descriptor,
                          JSBool is_static_method,
                          uintN argc, jsval *argv)
{
    int cost, lowest_cost, num_method_matches;
    JavaMethodSpec *best_method_match, *method;

    num_method_matches = 0;
    lowest_cost = 10000;
    best_method_match = NULL;

    for (method = member_descriptor->methods; method; method = method->next) {
        cost = 0;
        if (!method_signature_matches_JS_args(cx, jEnv, argc, argv, &method->signature, &cost))
            continue;

        if (cost < lowest_cost) {
            lowest_cost = cost;
            best_method_match = method;
            num_method_matches++;
        }
    }

    if (!best_method_match)
        report_method_match_failure(cx, member_descriptor, class_descriptor,
                                    is_static_method, argc, argv);

    if (lowest_cost != 0)
        return NULL;

    return best_method_match;
}

#else   /* !OLD_STYLE_METHOD_RESOLUTION */

/*
 * Determine the more natural (preferred) JavaScript->Java conversion
 * given one JavaScript value and two Java types.
 * See http://www.mozilla.org/js/liveconnect/lc3_method_overloading.html
 * for details.
 */
static JSJTypePreference
preferred_conversion(JSContext *cx, JNIEnv *jEnv, jsval js_val,
                     JavaClassDescriptor *descriptor1,
                     JavaClassDescriptor *descriptor2)
{
    JSJType js_type;
    int rank1, rank2;
    jclass java_class1, java_class2;
    JavaObjectWrapper *java_wrapper;
    jobject java_obj;
    JSObject *js_obj;
    
    js_type = compute_jsj_type(cx, js_val);
    rank1 = rank_table[js_type][(int)descriptor1->type - 2];
    rank2 = rank_table[js_type][(int)descriptor2->type - 2];
        
    /* Fast path for conversion from most JS types */  
    if (rank1 < rank2)
        return JSJPREF_FIRST_ARG;

    /*
     * Special logic is required for matching the classes of wrapped
     * Java objects.
     */
    if (rank2 == 0) {
        java_class1 = descriptor1->java_class;
        java_class2 = descriptor2->java_class;
        
        js_obj = JSVAL_TO_OBJECT(js_val);
        java_wrapper = JS_GetPrivate(cx, js_obj);
        java_obj = java_wrapper->java_obj;
        
        /* Unwrapped JavaObject must be compatible with Java arg type */
        if (!(*jEnv)->IsInstanceOf(jEnv, java_obj, java_class2))
            return JSJPREF_FIRST_ARG;

        /*
         * For JavaObject arguments, any compatible reference type is preferable
         * to any primitive Java type or to java.lang.String.
         */
        if (rank1 != 0)
            return JSJPREF_SECOND_ARG;
        
        /*
         * If argument of type descriptor1 is subclass of type descriptor 2, then
         * descriptor1 is preferred and vice-versa.
         */
        if ((*jEnv)->IsAssignableFrom(jEnv, java_class1, java_class2))
            return JSJPREF_FIRST_ARG;
        
        if ((*jEnv)->IsAssignableFrom(jEnv, java_class2, java_class1))
            return JSJPREF_SECOND_ARG;

        /* This can happen in unusual situations involving interface types. */
        return JSJPREF_AMBIGUOUS;
    }
    
    if (rank1 > rank2)
        return JSJPREF_SECOND_ARG;
    
    return JSJPREF_AMBIGUOUS;
}
              
static JSJTypePreference
method_preferred(JSContext *cx, JNIEnv *jEnv, jsval *argv,
                 JavaMethodSignature *method_signature1,
                 JavaMethodSignature *method_signature2)
{
    int arg_index, argc, preference;
    jsval val;
    JavaSignature* *arg_signatures1;
    JavaSignature* *arg_signatures2;
    JavaSignature *arg_type1, *arg_type2;

    arg_signatures1 = method_signature1->arg_signatures;
    arg_signatures2 = method_signature2->arg_signatures;
    argc = method_signature1->num_args;
    JS_ASSERT(argc == method_signature2->num_args);

    preference = 0;
    for (arg_index = 0; arg_index < argc; arg_index++) {
        val = argv[arg_index];
        arg_type1 = *arg_signatures1++;
        arg_type2 = *arg_signatures2++;

        if (arg_type1 == arg_type2)
            continue;

        preference |= preferred_conversion(cx, jEnv, val, arg_type1, arg_type2);

        if ((JSJTypePreference)preference == JSJPREF_AMBIGUOUS)
            return JSJPREF_AMBIGUOUS;
    }
    return (JSJTypePreference)preference;
}

/*
 * This routine applies heuristics to guess the intended Java method given the
 * runtime JavaScript argument types and the type signatures of the candidate
 * methods.  Informally, the method with Java parameter types that most closely
 * match the JavaScript types is chosen.  A more precise specification is
 * provided in the lc3_method_resolution.html file.  The code uses a very
 * brute-force approach.
 */
static JavaMethodSpec *
resolve_overloaded_method(JSContext *cx, JNIEnv *jEnv,
                          JavaMemberDescriptor *member_descriptor,
                          JavaClassDescriptor *class_descriptor,
                          JSBool is_static_method,
                          uintN argc, jsval *argv)
{
    JSJTypePreference preference;
    JavaMethodSpec *method, *best_method_match;
    MethodList ambiguous_methods;
    MethodListElement *method_list_element, *next_element;

    /*
     * Determine the first Java method among the overloaded methods of the same name
     * that matches all the JS arguments.
     */
    for (method = member_descriptor->methods; method; method = method->next) {
        if (method_signature_matches_JS_args(cx, jEnv, argc, argv, &method->signature))
            break;
    }

    /* Report an error if no method matched the JS arguments */
    if (!method) {
        report_method_match_failure(cx, member_descriptor, class_descriptor,
                                    is_static_method, argc, argv);
        return NULL;
    }

    /* Shortcut a common case */
    if (!method->next)
        return method;

    /*
     * Form a list of all methods that are neither more or less preferred than the
     * best matching method discovered so far.
     */
    JS_INIT_CLIST(&ambiguous_methods);

    best_method_match = method;

    /* See if there are any Java methods that are a better fit for the JS args */
    for (method = method->next; method; method = method->next) {
        if (method->signature.num_args != (int)argc)
            continue;
        preference = method_preferred(cx, jEnv, argv, &best_method_match->signature,
                                      &method->signature);
        if (preference == JSJPREF_SECOND_ARG) {
            best_method_match = method;
        } else  if (preference == JSJPREF_AMBIGUOUS) {
            /* Add this method to the list of ambiguous methods */
            method_list_element =
                (MethodListElement*)JS_malloc(cx, sizeof(MethodListElement));
            if (!method_list_element)
                goto error;
            method_list_element->method = method;
            JS_APPEND_LINK(&method_list_element->linkage, &ambiguous_methods);
        }
    }
    
    /*
     * Ensure that best_method_match is preferred to all methods on the
     * ambiguous_methods list.
     */
    
    for (method_list_element = (MethodListElement*)JS_LIST_HEAD(&ambiguous_methods);
        (MethodList*)method_list_element != &ambiguous_methods;
         method_list_element = next_element) {
        next_element = (MethodListElement*)method_list_element->linkage.next;
        method = method_list_element->method;
        preference = method_preferred(cx, jEnv, argv, &best_method_match->signature,
                                      &method->signature);
        if (preference != JSJPREF_FIRST_ARG)
            continue;
        JS_REMOVE_LINK(&method_list_element->linkage);
        JS_free(cx, method_list_element);
    }
    
    /*
     * The chosen method must be maximally preferred, i.e. there can be no other
     * method that is just as preferred.
     */
    if (!JS_CLIST_IS_EMPTY(&ambiguous_methods)) {
        /* Add the best_method_match to the list of ambiguous methods */
      method_list_element =
          (MethodListElement*)JS_malloc(cx, sizeof(MethodListElement));
      if (!method_list_element)
          goto error;
      method_list_element->method = best_method_match;
      JS_APPEND_LINK(&method_list_element->linkage, &ambiguous_methods);

      /* Report the problem */
        report_ambiguous_method_match(cx, member_descriptor, class_descriptor,
                                      &ambiguous_methods, is_static_method, argc, argv);
        goto error;
    }

    return best_method_match;

error:
    /* Delete the storage for the ambiguous_method list */
    while (!JS_CLIST_IS_EMPTY(&ambiguous_methods)) {
        method_list_element = (MethodListElement*)JS_LIST_HEAD(&ambiguous_methods);
        JS_REMOVE_LINK(&method_list_element->linkage);
        JS_free(cx, method_list_element);
    }

    return NULL;
}

#endif  /* !HAS_OLD_STYLE_METHOD_RESOLUTION */

static jvalue *
convert_JS_method_args_to_java_argv(JSContext *cx, JNIEnv *jEnv, jsval *argv,
                        JavaMethodSpec *method, JSBool **localvp)
{
    jvalue *jargv;
    JSBool ok, *localv;
    uintN i, argc;
    JavaSignature **arg_signatures;
    JavaMethodSignature *signature;
    
    
    signature = &method->signature;
    argc = signature->num_args;
    JS_ASSERT(argc != 0);
    arg_signatures = signature->arg_signatures;
    
    jargv = (jvalue *)JS_malloc(cx, sizeof(jvalue) * argc);
    
    if (!jargv)
        return NULL;

    /*
     * Allocate an array that contains a flag for each argument, indicating whether
     * or not the conversion from a JS value to a Java value resulted in a new
     * JNI local reference.
     */
    localv = (JSBool *)JS_malloc(cx, sizeof(JSBool) * argc);
    *localvp = localv;
    if (!localv) {
        JS_free(cx, jargv);
        return NULL;
    }
 
    for (i = 0; i < argc; i++) {
        int dummy_cost;
        
        ok = jsj_ConvertJSValueToJavaValue(cx, jEnv, argv[i], arg_signatures[i],
                                           &dummy_cost, &jargv[i], &localv[i]);
        if (!ok) {
            JS_free(cx, jargv);
            JS_free(cx, localv);
            *localvp = NULL;
            return NULL;
        }
    }

    return jargv;
}  

static JSBool
invoke_java_method(JSContext *cx, JSJavaThreadState *jsj_env,
                   jobject java_class_or_instance,
                   JavaClassDescriptor *class_descriptor,
                   JavaMethodSpec *method,
                   JSBool is_static_method,
                   jsval *argv, jsval *vp)
{
    jvalue java_value;
    jvalue *jargv;
    uintN argc, i;
    jobject java_object;
    jclass java_class;
    jmethodID methodID;
    JavaMethodSignature *signature;
    JavaSignature *return_val_signature;
    JNIEnv *jEnv;
    JSBool *localv, error_occurred, success;

    success = error_occurred = JS_FALSE;
    return_val_signature = NULL;    /* Quiet gcc uninitialized variable warning */

    methodID = method->methodID;
    signature = &method->signature;
    argc = signature->num_args;

    jEnv = jsj_env->jEnv;

    if (is_static_method) {
        java_object = NULL;
        java_class = java_class_or_instance;
    } else {
        java_object = java_class_or_instance;
        java_class = NULL;
    }

    jargv = NULL;
    localv = NULL;
    if (argc) {
        jargv = convert_JS_method_args_to_java_argv(cx, jEnv, argv, method, &localv);
        if (!jargv) {
            error_occurred = JS_TRUE;
            goto out;
        }
    }

    /* Prevent deadlocking if we re-enter JS on another thread as a result of a Java
       method call and that new thread wants to perform a GC. */
#ifdef JSJ_THREADSAFE
    JS_EndRequest(cx);
#endif

#define CALL_JAVA_METHOD(type, member)                                       \
    JS_BEGIN_MACRO                                                           \
    if (is_static_method) {                                                  \
        java_value.member = (*jEnv)->CallStatic##type##MethodA(jEnv, java_class, methodID, jargv);\
    } else {                                                                 \
        java_value.member = (*jEnv)->Call##type##MethodA(jEnv, java_object, methodID, jargv);\
    }                                                                        \
    if ((*jEnv)->ExceptionOccurred(jEnv)) {                                  \
        jsj_ReportJavaError(cx, jEnv, "Error calling method %s.%s()",        \
                            class_descriptor->name, method->name);           \
        error_occurred = JS_TRUE;                                            \
        goto out;                                                            \
    }                                                                        \
    JS_END_MACRO

    return_val_signature = signature->return_val_signature;
    switch(return_val_signature->type) {
    case JAVA_SIGNATURE_BYTE:
        CALL_JAVA_METHOD(Byte, b);
        break;

    case JAVA_SIGNATURE_CHAR:
        CALL_JAVA_METHOD(Char, c);
        break;
    
    case JAVA_SIGNATURE_FLOAT:
        CALL_JAVA_METHOD(Float, f);
        break;
    
    case JAVA_SIGNATURE_DOUBLE:
        CALL_JAVA_METHOD(Double, d);
        break;
    
    case JAVA_SIGNATURE_INT:
        CALL_JAVA_METHOD(Int, i);
        break;
    
    case JAVA_SIGNATURE_LONG:
        CALL_JAVA_METHOD(Long, j);
        break;
    
    case JAVA_SIGNATURE_SHORT:
        CALL_JAVA_METHOD(Short, s);
        break;
    
    case JAVA_SIGNATURE_BOOLEAN:
        CALL_JAVA_METHOD(Boolean, z);
        break;
    
    case JAVA_SIGNATURE_VOID:
        if (is_static_method)
            (*jEnv)->CallStaticVoidMethodA(jEnv, java_class, methodID, jargv);
        else
            (*jEnv)->CallVoidMethodA(jEnv, java_object, methodID, jargv);
        if ((*jEnv)->ExceptionOccurred(jEnv)) {
            jsj_ReportJavaError(cx, jEnv, "Error calling method %s.%s()",
                                class_descriptor->name, method->name);
            error_occurred = JS_TRUE;
            goto out;
        }
        break;
        
    case JAVA_SIGNATURE_UNKNOWN:
        JS_ASSERT(0);
        error_occurred = JS_TRUE;
        goto out;
            
    /* Non-primitive (reference) type */
    default:
        JS_ASSERT(IS_REFERENCE_TYPE(return_val_signature->type));
        CALL_JAVA_METHOD(Object, l);
        break;
    }

out:

    if (localv) {
        for (i = 0; i < argc; i++) {
            if (localv[i])
                (*jEnv)->DeleteLocalRef(jEnv, jargv[i].l);
        }
        JS_free(cx, localv);
    }
    if (jargv)
       JS_free(cx, jargv);

#ifdef JSJ_THREADSAFE
    JS_BeginRequest(cx);
#endif

    if (!error_occurred) {
        success = jsj_ConvertJavaValueToJSValue(cx, jEnv, return_val_signature, &java_value, vp);
        if (IS_REFERENCE_TYPE(return_val_signature->type))
            (*jEnv)->DeleteLocalRef(jEnv, java_value.l);
    }
    return success;
}

static JSBool
invoke_overloaded_java_method(JSContext *cx, JSJavaThreadState *jsj_env,
                              JavaMemberDescriptor *member,
                              JSBool is_static_method,
                              jobject java_class_or_instance,
                              JavaClassDescriptor *class_descriptor,
                              uintN argc, jsval *argv,
                              jsval *vp)
{
    JavaMethodSpec *method;
    JNIEnv *jEnv;

    jEnv = jsj_env->jEnv;

    method = resolve_overloaded_method(cx, jEnv, member, class_descriptor,
                                       is_static_method, argc, argv);
    if (!method)
        return JS_FALSE;

    return invoke_java_method(cx, jsj_env, java_class_or_instance, class_descriptor, 
                              method, is_static_method, argv, vp);
}

static JSBool
invoke_java_constructor(JSContext *cx,
                        JSJavaThreadState *jsj_env,
                        jclass java_class,
                JavaMethodSpec *method,
                jsval *argv, jsval *vp)
{
    jvalue *jargv;
    uintN argc, i;
    jobject java_object;
    jmethodID methodID;
    JavaMethodSignature *signature;
    JNIEnv *jEnv;
    JSBool *localv;
    JSBool success, error_occurred;
    java_object = NULL;     /* Stifle gcc uninitialized variable warning */

    success = error_occurred = JS_FALSE;
    
    methodID = method->methodID;
    signature = &method->signature;
    argc = signature->num_args;

    jEnv = jsj_env->jEnv;

    jargv = NULL;
    localv = NULL;
    if (argc) {
        jargv = convert_JS_method_args_to_java_argv(cx, jEnv, argv, method, &localv);
        if (!jargv) {
            error_occurred = JS_TRUE;
            goto out;
        }
    }

    /* Prevent deadlocking if we re-enter JS on another thread as a result of a Java
       method call and that new thread wants to perform a GC. */
#ifdef JSJ_THREADSAFE
    JS_EndRequest(cx);
#endif

    /* Call the constructor */
    java_object = (*jEnv)->NewObjectA(jEnv, java_class, methodID, jargv);

#ifdef JSJ_THREADSAFE
    JS_BeginRequest(cx);
#endif

    if (!java_object) {
        jsj_ReportJavaError(cx, jEnv, "Error while constructing instance of %s",
                            jsj_GetJavaClassName(cx, jEnv, java_class));
        error_occurred = JS_TRUE;
        goto out;
    }

out:
    if (localv) {
        for (i = 0; i < argc; i++) {
            if (localv[i])
                (*jEnv)->DeleteLocalRef(jEnv, jargv[i].l);
        }
        JS_free(cx, localv);
    }
    if (jargv)
       JS_free(cx, jargv);
        
    if (!error_occurred)
        success = jsj_ConvertJavaObjectToJSValue(cx, jEnv, java_object, vp);
    (*jEnv)->DeleteLocalRef(jEnv, java_object);
    return success;
}

static JSBool
invoke_overloaded_java_constructor(JSContext *cx,
                                   JSJavaThreadState *jsj_env,
                                   JavaMemberDescriptor *member,
                                   JavaClassDescriptor *class_descriptor,
                                   uintN argc, jsval *argv,
                                   jsval *vp)
{
    jclass java_class;
    JavaMethodSpec *method;
    JNIEnv *jEnv;

    jEnv = jsj_env->jEnv;

    method = resolve_overloaded_method(cx, jEnv, member, class_descriptor, JS_TRUE, 
                                       argc, argv);
    if (!method)
        return JS_FALSE;

    java_class = class_descriptor->java_class;
    return invoke_java_constructor(cx, jsj_env, java_class, method, argv, vp);
}

static JSBool
java_constructor_wrapper(JSContext *cx, JSJavaThreadState *jsj_env,
                         JavaMemberDescriptor *member_descriptor,
                         JavaClassDescriptor *class_descriptor,
                         uintN argc, jsval *argv, jsval *vp)
{
    jint modifiers;
    JNIEnv *jEnv;

    jEnv = jsj_env->jEnv;
    
    /* Get class/interface flags and check them */
    modifiers = class_descriptor->modifiers;
    if (modifiers & ACC_ABSTRACT) {
        JS_ReportErrorNumber(cx, jsj_GetErrorMessage, NULL, 
                            JSJMSG_ABSTRACT_JCLASS, class_descriptor->name);
        return JS_FALSE;
    }
    if (modifiers & ACC_INTERFACE) {
        JS_ReportErrorNumber(cx, jsj_GetErrorMessage, NULL, 
                            JSJMSG_IS_INTERFACE, class_descriptor->name);
        return JS_FALSE;
    }
    if ( !(modifiers & ACC_PUBLIC) ) {
        JS_ReportErrorNumber(cx, jsj_GetErrorMessage, NULL, 
                            JSJMSG_NOT_PUBLIC, class_descriptor->name);
        return JS_FALSE;
    }
    
    if (!member_descriptor) {
        JS_ReportErrorNumber(cx, jsj_GetErrorMessage, NULL, 
                            JSJMSG_NO_CONSTRUCTORS, class_descriptor->name);
        return JS_FALSE;
    }

    return invoke_overloaded_java_constructor(cx, jsj_env, member_descriptor,
                                              class_descriptor, argc, argv, vp);
}

JS_EXPORT_API(JSBool)
jsj_JavaConstructorWrapper(JSContext *cx, JSObject *obj,
                           uintN argc, jsval *argv, jsval *vp)
{
    JavaClassDescriptor *class_descriptor;
    JavaMemberDescriptor *member_descriptor;
    JSJavaThreadState *jsj_env;
    JNIEnv *jEnv;
    JSBool result;

    obj = JSVAL_TO_OBJECT(argv[-2]);
    class_descriptor = JS_GetPrivate(cx, obj);
    JS_ASSERT(class_descriptor);
    if (!class_descriptor)
        return JS_FALSE;

    /* XXX, workaround for bug 200016, all classes in sun.plugin package should not 
       be accessible in liveconnect.
       Ideally, this checking should be done in JPI side, but it's not going to happen 
       until Sun JRE 1.5.1 */
    if (strstr(class_descriptor->name, "sun.plugin.") == class_descriptor->name)
        return JS_FALSE;
  
    /* Get the Java per-thread environment pointer for this JSContext */
    jsj_env = jsj_EnterJava(cx, &jEnv);
    if (!jEnv)
        return JS_FALSE;
    member_descriptor = jsj_LookupJavaClassConstructors(cx, jEnv, class_descriptor);
    result = java_constructor_wrapper(cx, jsj_env, member_descriptor, 
                                      class_descriptor, argc, argv, vp);
    jsj_ExitJava(jsj_env);
    return result;
}


static JSBool
static_method_wrapper(JSContext *cx, JSJavaThreadState *jsj_env,
                      JavaClassDescriptor *class_descriptor,
                      jsid id,
                      uintN argc, jsval *argv, jsval *vp)
{
    JNIEnv *jEnv;
    JavaMemberDescriptor *member_descriptor;

    jEnv = jsj_env->jEnv;
    member_descriptor = jsj_LookupJavaStaticMemberDescriptorById(cx, jEnv, class_descriptor, id);
    
    /* Is it a static method that is not a constructor ? */
    if (member_descriptor && strcmp(member_descriptor->name, "<init>")) {
        return invoke_overloaded_java_method(cx, jsj_env, member_descriptor, JS_TRUE, 
                                             class_descriptor->java_class,
                                             class_descriptor, argc, argv, vp);
    }

    JS_ASSERT(member_descriptor);
    if (!member_descriptor)
        return JS_FALSE;
    
    /* Must be an explicitly resolved overloaded constructor */
    return java_constructor_wrapper(cx, jsj_env, member_descriptor,
                                    class_descriptor, argc, argv, vp);
}

JS_EXTERN_API(JSBool)
jsj_JavaStaticMethodWrapper(JSContext *cx, JSObject *obj,
                            uintN argc, jsval *argv, jsval *vp)
{
    JSFunction *function;
    JavaClassDescriptor *class_descriptor;
    jsid id;
    jsval idval;
    JNIEnv *jEnv;
    JSJavaThreadState *jsj_env;
    JSBool result;
    
    class_descriptor = JS_GetPrivate(cx, obj);
    if (!class_descriptor)
        return JS_FALSE;

    /* Get the Java per-thread environment pointer for this JSContext */
    jsj_env = jsj_EnterJava(cx, &jEnv);
    if (!jEnv)
        return JS_FALSE;
    
    JS_ASSERT(JS_TypeOfValue(cx, argv[-2]) == JSTYPE_FUNCTION);
    function = JS_GetPrivate(cx, JSVAL_TO_OBJECT(argv[-2]));
    idval = STRING_TO_JSVAL(JS_InternString(cx, JS_GetFunctionName(function)));
    JS_ValueToId(cx, idval, &id);

    result = static_method_wrapper(cx, jsj_env, class_descriptor, id, argc, argv, vp);
    jsj_ExitJava(jsj_env);
    return result;
}

JS_EXPORT_API(JSBool)
jsj_JavaInstanceMethodWrapper(JSContext *cx, JSObject *obj,
                              uintN argc, jsval *argv, jsval *vp)
{
    JSFunction *function;
    JavaMemberDescriptor *member_descriptor;
    JavaObjectWrapper *java_wrapper;
    JavaClassDescriptor *class_descriptor;
    jsid id;
    jsval idval;
    JSJavaThreadState *jsj_env;
    JNIEnv *jEnv;
    jobject java_obj;
    JSBool result;
    
    java_wrapper = JS_GetPrivate(cx, obj);
    if (!java_wrapper)
        return JS_FALSE;
    java_obj = java_wrapper->java_obj;
    
    JS_ASSERT(JS_TypeOfValue(cx, argv[-2]) == JSTYPE_FUNCTION);
    function = JS_GetPrivate(cx, JSVAL_TO_OBJECT(argv[-2]));
    idval = STRING_TO_JSVAL(JS_InternString(cx, JS_GetFunctionName(function)));
    JS_ValueToId(cx, idval, &id);
    class_descriptor = java_wrapper->class_descriptor;
    
    /* Get the Java per-thread environment pointer for this JSContext */
    jsj_env = jsj_EnterJava(cx, &jEnv);
    if (!jEnv)
        return JS_FALSE;

    if (jaApplet && (*jEnv)->IsInstanceOf(jEnv, java_obj, jaApplet)) {
        jsj_JSIsCallingApplet = JS_TRUE;
    }

    /* Try to find an instance method with the given name first */
    member_descriptor = jsj_LookupJavaMemberDescriptorById(cx, jEnv, class_descriptor, id);
    if (member_descriptor)
        result = invoke_overloaded_java_method(cx, jsj_env, member_descriptor,
                                               JS_FALSE, java_obj, 
                                               class_descriptor, argc, argv, vp);

    /* If no instance method was found, try for a static method or constructor */
    else
      result = static_method_wrapper(cx, jsj_env, class_descriptor, id, argc, argv, vp);
    jsj_ExitJava(jsj_env);
    return result;
}


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