/*

 * 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.  Oracle designates this

 * particular file as subject to the "Classpath" exception as provided

 * by Oracle in the LICENSE file that accompanied this code.

 *

 * 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 "java_net_SocketOutputStream.h"

/************************************************************************

 * SocketOutputStream

 */

static jfieldID IO_fd_fdID;

/*

 * Class:     java_net_SocketOutputStream

 * Method:    init

 * Signature: ()V

 */

JNIEXPORT void JNICALL

Java_java_net_SocketOutputStream_init(JNIEnv *env, jclass cls) {

    IO_fd_fdID = NET_GetFileDescriptorID(env);

}

/*

 * Class:     java_net_SocketOutputStream

 * Method:    socketWrite

 * Signature: (Ljava/io/FileDescriptor;[BII)V

 */

JNIEXPORT void JNICALL

Java_java_net_SocketOutputStream_socketWrite0(JNIEnv *env, jobject this,

                                              jobject fdObj, jbyteArray data,

                                              jint off, jint len) {

    char *bufP;

    char BUF[MAX_BUFFER_LEN];

    int buflen;

    int fd;

    if (IS_NULL(fdObj)) {

        JNU_ThrowByName(env, JNU_JAVANETPKG "SocketException", "Socket closed");

        return;

    } else {

        fd = (*env)->GetIntField(env, fdObj, IO_fd_fdID);

    }

    if (IS_NULL(data)) {

        JNU_ThrowNullPointerException(env, "data argument");

        return;

    }

    /*

     * Use stack allocate buffer if possible. For large sizes we allocate

     * an intermediate buffer from the heap (up to a maximum). If heap is

     * unavailable just use our stack buffer.

     */

    if (len <= MAX_BUFFER_LEN) {

        bufP = BUF;

        buflen = MAX_BUFFER_LEN;

    } else {

        buflen = min(MAX_HEAP_BUFFER_LEN, len);

        bufP = (char *)malloc((size_t)buflen);

        if (bufP == NULL) {

            bufP = BUF;

            buflen = MAX_BUFFER_LEN;

        }

    }

    while(len > 0) {

        int loff = 0;

        int chunkLen = min(buflen, len);

        int llen = chunkLen;

        int retry = 0;

        (*env)->GetByteArrayRegion(env, data, off, chunkLen, (jbyte *)bufP);

        while(llen > 0) {

            int n = send(fd, bufP + loff, llen, 0);

            if (n > 0) {

                llen -= n;

                loff += n;

                continue;

            }

            /*

             * Due to a bug in Windows Sockets (observed on NT and Windows

             * 2000) it may be necessary to retry the send. The issue is that

             * on blocking sockets send/WSASend is supposed to block if there

             * is insufficient buffer space available. If there are a large

             * number of threads blocked on write due to congestion then it's

             * possile to hit the NT/2000 bug whereby send returns WSAENOBUFS.

             * The workaround we use is to retry the send. If we have a

             * large buffer to send (>2k) then we retry with a maximum of

             * 2k buffer. If we hit the issue with <=2k buffer then we backoff

             * for 1 second and retry again. We repeat this up to a reasonable

             * limit before bailing out and throwing an exception. In load

             * conditions we've observed that the send will succeed after 2-3

             * attempts but this depends on network buffers associated with

             * other sockets draining.

             */

            if (WSAGetLastError() == WSAENOBUFS) {

                if (llen > MAX_BUFFER_LEN) {

                    buflen = MAX_BUFFER_LEN;

                    chunkLen = MAX_BUFFER_LEN;

                    llen = MAX_BUFFER_LEN;

                    continue;

                }

                if (retry >= 30) {

                    JNU_ThrowByName(env, JNU_JAVANETPKG "SocketException",

                        "No buffer space available - exhausted attempts to queue buffer");

                    if (bufP != BUF) {

                        free(bufP);

                    }

                    return;

                }

                Sleep(1000);

                retry++;

                continue;

            }

            /*

             * Send failed - can be caused by close or write error.

             */

            if (WSAGetLastError() == WSAENOTSOCK) {

                JNU_ThrowByName(env, JNU_JAVANETPKG "SocketException", "Socket closed");

            } else {

                NET_ThrowCurrent(env, "socket write error");

            }

            if (bufP != BUF) {

                free(bufP);

            }

            return;

        }

        len -= chunkLen;

        off += chunkLen;

    }

    if (bufP != BUF) {

        free(bufP);

    }

}