JDK14/Java14源码在线阅读

/*
 * Copyright (c) 1997, 2016, 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.  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 <malloc.h>

#include "net_util.h"

#include "java_net_SocketInputStream.h"

/*************************************************************************
 * SocketInputStream
 */
static jfieldID IO_fd_fdID;

/*
 * Class:     java_net_SocketInputStream
 * Method:    init
 * Signature: ()V
 */
JNIEXPORT void JNICALL
Java_java_net_SocketInputStream_init(JNIEnv *env, jclass cls) {
    IO_fd_fdID = NET_GetFileDescriptorID(env);
}

/*
 * Class:     java_net_SocketInputStream
 * Method:    socketRead
 * Signature: (Ljava/io/FileDescriptor;[BIII)I
 */
JNIEXPORT jint JNICALL
Java_java_net_SocketInputStream_socketRead0(JNIEnv *env, jobject this,
                                            jobject fdObj, jbyteArray data,
                                            jint off, jint len, jint timeout)
{
    char BUF[MAX_BUFFER_LEN];
    char *bufP;
    jint fd, newfd, nread;

    if (IS_NULL(fdObj)) {
        JNU_ThrowByName(env, "java/net/SocketException",
                        "Socket closed");
        return -1;
    }
    fd = (*env)->GetIntField(env, fdObj, IO_fd_fdID);
    if (fd == -1) {
        JNU_ThrowByName(env, "java/net/SocketException", "Socket closed");
        return -1;
    }

    /*
     * If the caller buffer is large than our stack buffer then we allocate
     * from the heap (up to a limit). If memory is exhausted we always use
     * the stack buffer.
     */
    if (len <= MAX_BUFFER_LEN) {
        bufP = BUF;
    } else {
        if (len > MAX_HEAP_BUFFER_LEN) {
            len = MAX_HEAP_BUFFER_LEN;
        }
        bufP = (char *)malloc((size_t)len);
        if (bufP == NULL) {
            /* allocation failed so use stack buffer */
            bufP = BUF;
            len = MAX_BUFFER_LEN;
        }
    }


    if (timeout) {
        if (timeout <= 5000 || !isRcvTimeoutSupported) {
            int ret = NET_Timeout (fd, timeout);

            if (ret <= 0) {
                if (ret == 0) {
                    JNU_ThrowByName(env, "java/net/SocketTimeoutException",
                                    "Read timed out");
                } else if (ret == -1) {
                    JNU_ThrowByName(env, "java/net/SocketException", "socket closed");
                }
                if (bufP != BUF) {
                    free(bufP);
                }
                return -1;
            }

            /*check if the socket has been closed while we were in timeout*/
            newfd = (*env)->GetIntField(env, fdObj, IO_fd_fdID);
            if (newfd == -1) {
                JNU_ThrowByName(env, "java/net/SocketException", "Socket closed");
                if (bufP != BUF) {
                    free(bufP);
                }
                return -1;
            }
        }
    }

    nread = recv(fd, bufP, len, 0);
    if (nread > 0) {
        (*env)->SetByteArrayRegion(env, data, off, nread, (jbyte *)bufP);
    } else {
        if (nread < 0) {
            int err = WSAGetLastError();
            // Check if the socket has been closed since we last checked.
            // This could be a reason for recv failing.
            if ((*env)->GetIntField(env, fdObj, IO_fd_fdID) == -1) {
                JNU_ThrowByName(env, "java/net/SocketException", "Socket closed");
            } else {
                switch (err) {
                    case WSAEINTR:
                        JNU_ThrowByName(env, "java/net/SocketException",
                            "socket closed");
                        break;

                    case WSAECONNRESET:
                    case WSAESHUTDOWN:
                        /*
                         * Connection has been reset - Windows sometimes reports
                         * the reset as a shutdown error.
                         */

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