src/java.base/share/native/libjava/FileInputStream.c

/*
 * Copyright (c) 1997, 2024, 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 <fcntl.h>
#include <limits.h>

#include "jni.h"
#include "jni_util.h"
#include "jlong.h"
#include "io_util.h"

#include "jvm.h"

#include "java_io_FileInputStream.h"

#include "io_util_md.h"

/*******************************************************************/
/*  BEGIN JNI ********* BEGIN JNI *********** BEGIN JNI ************/
/*******************************************************************/

jfieldID fis_fd; /* id for jobject 'fd' in java.io.FileInputStream */

/**************************************************************
 * static methods to store field ID's in initializers
 */

JNIEXPORT void JNICALL
Java_java_io_FileInputStream_initIDs(JNIEnv *env, jclass fdClass) {
    fis_fd = (*env)->GetFieldID(env, fdClass, "fd", "Ljava/io/FileDescriptor;");
}

/**************************************************************
 * Input stream
 */

JNIEXPORT void JNICALL
Java_java_io_FileInputStream_open0(JNIEnv *env, jobject this, jstring path) {
    fileOpen(env, this, path, fis_fd, O_RDONLY);
}

JNIEXPORT jint JNICALL
Java_java_io_FileInputStream_read0(JNIEnv *env, jobject this) {
    return readSingle(env, this, fis_fd);
}

JNIEXPORT jint JNICALL
Java_java_io_FileInputStream_readBytes(JNIEnv *env, jobject this,
        jbyteArray bytes, jint off, jint len) {
    return readBytes(env, this, bytes, off, len, fis_fd);
}

JNIEXPORT jlong JNICALL
Java_java_io_FileInputStream_length0(JNIEnv *env, jobject this) {

    FD fd;
    jlong length = jlong_zero;

    fd = getFD(env, this, fis_fd);
    if (fd == -1) {
        JNU_ThrowIOException(env, "Stream Closed");
        return -1;
    }
    if ((length = IO_GetLength(fd)) == -1) {
        JNU_ThrowIOExceptionWithLastError(env, "GetLength failed");
    }
    return length;
}

JNIEXPORT jlong JNICALL
Java_java_io_FileInputStream_position0(JNIEnv *env, jobject this) {
    FD fd;
    jlong ret;

    fd = getFD(env, this, fis_fd);
    if (fd == -1) {
        JNU_ThrowIOException(env, "Stream Closed");
        return -1;
    }
    if ((ret = IO_Lseek(fd, 0L, SEEK_CUR)) == -1) {
        JNU_ThrowIOExceptionWithLastError(env, "Seek failed");
    }
    return ret;
}

JNIEXPORT jlong JNICALL
Java_java_io_FileInputStream_skip0(JNIEnv *env, jobject this, jlong toSkip) {
    jlong cur = jlong_zero;
    jlong end = jlong_zero;
    FD fd = getFD(env, this, fis_fd);
    if (fd == -1) {
        JNU_ThrowIOException (env, "Stream Closed");
        return 0;
    }
    if ((cur = IO_Lseek(fd, (jlong)0, (jint)SEEK_CUR)) == -1) {
        JNU_ThrowIOExceptionWithLastError(env, "Seek error");
    } else if ((end = IO_Lseek(fd, toSkip, (jint)SEEK_CUR)) == -1) {
        JNU_ThrowIOExceptionWithLastError(env, "Seek error");
    }
    return (end - cur);
}

JNIEXPORT jint JNICALL
Java_java_io_FileInputStream_available0(JNIEnv *env, jobject this) {
    jlong ret;
    FD fd = getFD(env, this, fis_fd);
    if (fd == -1) {
        JNU_ThrowIOException (env, "Stream Closed");
        return 0;
    }
    if (IO_Available(fd, &ret)) {
        if (ret > INT_MAX) {
            ret = (jlong) INT_MAX;
        } else if (ret < 0) {
            ret = 0;
        }
        return jlong_to_jint(ret);
    }
    JNU_ThrowIOExceptionWithLastError(env, NULL);
    return 0;
}

JNIEXPORT jboolean JNICALL
Java_java_io_FileInputStream_isRegularFile0(JNIEnv *env, jobject this, jobject fdo) {
    FD fd = getFD(env, this, fis_fd);
    return IO_IsRegularFile(env, fd);
}