/*
 * Copyright (c) 2003, 2018, Oracle and/or its affiliates. All rights reserved.
 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
 *
 * This code is free software; you can redistribute it and/or modify it
 * under the terms of the GNU General Public License version 2 only, as
 * published by the Free Software Foundation.
 *
 * This code is distributed in the hope that it will be useful, but WITHOUT
 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
 * version 2 for more details (a copy is included in the LICENSE file that
 * accompanied this code).
 *
 * You should have received a copy of the GNU General Public License version
 * 2 along with this work; if not, write to the Free Software Foundation,
 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
 *
 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
 * or visit www.oracle.com if you need additional information or have any
 * questions.
 */

#include <stdio.h>
#include <string.h>
#include <jvmti.h>
#include "agent_common.h"
#include "JVMTITools.h"

extern "C" {


#define STATUS_FAILED 2
#define PASSED 0

static jvmtiEnv *jvmti = NULL;
static jvmtiCapabilities caps;

#ifdef STATIC_BUILD
JNIEXPORT jint JNICALL Agent_OnLoad_redefclass001(JavaVM *jvm, char *options, void *reserved) {
    return Agent_Initialize(jvm, options, reserved);
}
JNIEXPORT jint JNICALL Agent_OnAttach_redefclass001(JavaVM *jvm, char *options, void *reserved) {
    return Agent_Initialize(jvm, options, reserved);
}
JNIEXPORT jint JNI_OnLoad_redefclass001(JavaVM *jvm, char *options, void *reserved) {
    return JNI_VERSION_1_8;
}
#endif
jint  Agent_Initialize(JavaVM *vm, char *options, void *reserved) {
    jint res;
    jvmtiError err;

    if ((res = vm->GetEnv((void **) &jvmti, JVMTI_VERSION_1_1)) != JNI_OK) {
        printf("%s: Failed to call GetEnv: error=%d\n", __FILE__, res);
        return JNI_ERR;
    }

    err = jvmti->GetPotentialCapabilities(&caps);
    if (err != JVMTI_ERROR_NONE) {
        printf("(GetPotentialCapabilities) unexpected error: %s (%d)\n",
               TranslateError(err), err);
        return JNI_ERR;
    }

    err = jvmti->AddCapabilities(&caps);
    if (err != JVMTI_ERROR_NONE) {
        printf("(AddCapabilities) unexpected error: %s (%d)\n",
               TranslateError(err), err);
        return JNI_ERR;
    }

    err = jvmti->GetCapabilities(&caps);
    if (err != JVMTI_ERROR_NONE) {
        printf("(GetCapabilities) unexpected error: %s (%d)\n",
               TranslateError(err), err);
        return JNI_ERR;
    }

    if (!caps.can_redefine_classes) {
        printf("Warning: RedefineClasses is not implemented\n");
    }

    return JNI_OK;
}

JNIEXPORT jint JNICALL
Java_nsk_jvmti_RedefineClasses_redefclass001_makeRedefinition(JNIEnv *env,
        jclass cls, jint fl, jclass redefCls, jbyteArray classBytes) {
    jvmtiClassDefinition classDef;
    jvmtiError err;

    if (jvmti == NULL) {
        printf("JVMTI client was not properly loaded!\n");
        return STATUS_FAILED;
    }

    if (!caps.can_redefine_classes) {
        return PASSED;
    }

/* filling the structure jvmtiClassDefinition */
    classDef.klass = redefCls;
    classDef.class_byte_count = env->GetArrayLength(classBytes);
    classDef.class_bytes = (unsigned char *) env->GetByteArrayElements(classBytes, NULL);

    if (fl == 2) {
        printf(">>>>>>>> Invoke RedefineClasses():\n");
        printf("\tnew class byte count=%d\n", classDef.class_byte_count);
    }
    err = jvmti->RedefineClasses(1, &classDef);
    if (err != JVMTI_ERROR_NONE) {
        printf("%s: Failed to call RedefineClasses():\n", __FILE__);
        printf("\tthe function returned error %d: %s\n",
            err, TranslateError(err));
        printf("\tFor more info about this error see the JVMTI spec.\n");
        return STATUS_FAILED;
    }
    if (fl == 2)
        printf("<<<<<<<< RedefineClasses() is successfully done\n");

    return PASSED;
}

}