/*
    * Copyright 2013 The Netty Project
    *
    * The Netty Project licenses this file to you under the Apache License,
    * version 2.0 (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.apache.org/licenses/LICENSE-2.0
    *
   * Unless required by applicable law or agreed to in writing, software
   * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
   * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
   * License for the specific language governing permissions and limitations
   * under the License.
   */
  package io.netty.channel.epoll;
  
  import io.netty.channel.DefaultFileRegion;
  import io.netty.channel.unix.Errors.NativeIoException;
  import io.netty.channel.unix.NativeInetAddress;
  import io.netty.channel.unix.Socket;
  import io.netty.util.internal.NativeLibraryLoader;
  import io.netty.util.internal.PlatformDependent;
  import io.netty.util.internal.SystemPropertyUtil;
  import io.netty.channel.unix.FileDescriptor;
  import io.netty.util.internal.ThrowableUtil;
  import io.netty.util.internal.logging.InternalLogger;
  import io.netty.util.internal.logging.InternalLoggerFactory;
  
  import java.io.IOException;
  import java.net.InetAddress;
  import java.nio.channels.ClosedChannelException;
  import java.util.Locale;
  
  import static io.netty.channel.epoll.NativeStaticallyReferencedJniMethods.epollerr;
  import static io.netty.channel.epoll.NativeStaticallyReferencedJniMethods.epollet;
  import static io.netty.channel.epoll.NativeStaticallyReferencedJniMethods.epollin;
  import static io.netty.channel.epoll.NativeStaticallyReferencedJniMethods.epollout;
  import static io.netty.channel.epoll.NativeStaticallyReferencedJniMethods.epollrdhup;
  import static io.netty.channel.epoll.NativeStaticallyReferencedJniMethods.iovMax;
  import static io.netty.channel.epoll.NativeStaticallyReferencedJniMethods.isSupportingSendmmsg;
  import static io.netty.channel.epoll.NativeStaticallyReferencedJniMethods.isSupportingTcpFastopen;
  import static io.netty.channel.epoll.NativeStaticallyReferencedJniMethods.kernelVersion;
  import static io.netty.channel.epoll.NativeStaticallyReferencedJniMethods.ssizeMax;
  import static io.netty.channel.epoll.NativeStaticallyReferencedJniMethods.tcpMd5SigMaxKeyLen;
  import static io.netty.channel.epoll.NativeStaticallyReferencedJniMethods.uioMaxIov;
  import static io.netty.channel.unix.Errors.ERRNO_EAGAIN_NEGATIVE;
  import static io.netty.channel.unix.Errors.ERRNO_EPIPE_NEGATIVE;
  import static io.netty.channel.unix.Errors.ERRNO_EWOULDBLOCK_NEGATIVE;
  import static io.netty.channel.unix.Errors.ioResult;
  import static io.netty.channel.unix.Errors.newConnectionResetException;
  import static io.netty.channel.unix.Errors.newIOException;
  
  /**
   * Native helper methods
   * <p><strong>Internal usage only!</strong>
   * <p>Static members which call JNI methods must be defined in {@link NativeStaticallyReferencedJniMethods}.
   */
  public final class Native {
      private static final InternalLogger logger = InternalLoggerFactory.getInstance(Native.class);
  
      static {
          try {
              // First, try calling a side-effect free JNI method to see if the library was already
              // loaded by the application.
              offsetofEpollData();
          } catch (UnsatisfiedLinkError ignore) {
              // The library was not previously loaded, load it now.
              loadNativeLibrary();
          }
          Socket.initialize();
      }
  
      // EventLoop operations and constants
      public static final int EPOLLIN = epollin();
      public static final int EPOLLOUT = epollout();
      public static final int EPOLLRDHUP = epollrdhup();
      public static final int EPOLLET = epollet();
      public static final int EPOLLERR = epollerr();
  
      public static final int IOV_MAX = iovMax();
      public static final int UIO_MAX_IOV = uioMaxIov();
      public static final boolean IS_SUPPORTING_SENDMMSG = isSupportingSendmmsg();
      public static final boolean IS_SUPPORTING_TCP_FASTOPEN = isSupportingTcpFastopen();
      public static final long SSIZE_MAX = ssizeMax();
      public static final int TCP_MD5SIG_MAXKEYLEN = tcpMd5SigMaxKeyLen();
      public static final String KERNEL_VERSION = kernelVersion();
  
      private static final NativeIoException SENDFILE_CONNECTION_RESET_EXCEPTION;
      private static final NativeIoException SENDMMSG_CONNECTION_RESET_EXCEPTION;
      private static final NativeIoException SPLICE_CONNECTION_RESET_EXCEPTION;
      private static final ClosedChannelException SENDFILE_CLOSED_CHANNEL_EXCEPTION = ThrowableUtil.unknownStackTrace(
              new ClosedChannelException(), Native.class, "sendfile(...)");
      private static final ClosedChannelException SENDMMSG_CLOSED_CHANNEL_EXCEPTION = ThrowableUtil.unknownStackTrace(
              new ClosedChannelException(), Native.class, "sendmmsg(...)");
      private static final ClosedChannelException SPLICE_CLOSED_CHANNEL_EXCEPTION = ThrowableUtil.unknownStackTrace(
              new ClosedChannelException(), Native.class, "splice(...)");
  
      static {
         SENDFILE_CONNECTION_RESET_EXCEPTION = newConnectionResetException("syscall:sendfile(...)",
                 ERRNO_EPIPE_NEGATIVE);
         SENDMMSG_CONNECTION_RESET_EXCEPTION = newConnectionResetException("syscall:sendmmsg(...)",
                 ERRNO_EPIPE_NEGATIVE);
         SPLICE_CONNECTION_RESET_EXCEPTION = newConnectionResetException("syscall:splice(...)",
                 ERRNO_EPIPE_NEGATIVE);
     }
 
     public static FileDescriptor newEventFd() {
         return new FileDescriptor(eventFd());
     }
 
     public static FileDescriptor newTimerFd() {
         return new FileDescriptor(timerFd());
     }
 
     private static native int eventFd();
     private static native int timerFd();
     public static native void eventFdWrite(int fd, long value);
     public static native void eventFdRead(int fd);
     static native void timerFdRead(int fd);
 
     public static FileDescriptor newEpollCreate() {
         return new FileDescriptor(epollCreate());
     }
 
     private static native int epollCreate();
 
     public static int epollWait(FileDescriptor epollFd, EpollEventArray events, FileDescriptor timerFd,
                                 int timeoutSec, int timeoutNs) throws IOException {
         int ready = epollWait0(epollFd.intValue(), events.memoryAddress(), events.length(), timerFd.intValue(),
                                timeoutSec, timeoutNs);
         if (ready < 0) {
             throw newIOException("epoll_wait", ready);
         }
         return ready;
     }
     private static native int epollWait0(int efd, long address, int len, int timerFd, int timeoutSec, int timeoutNs);
 
     public static void epollCtlAdd(int efd, final int fd, final int flags) throws IOException {
         int res = epollCtlAdd0(efd, fd, flags);
         if (res < 0) {
             throw newIOException("epoll_ctl", res);
         }
     }
     private static native int epollCtlAdd0(int efd, final int fd, final int flags);
 
     public static void epollCtlMod(int efd, final int fd, final int flags) throws IOException {
         int res = epollCtlMod0(efd, fd, flags);
         if (res < 0) {
             throw newIOException("epoll_ctl", res);
         }
     }
     private static native int epollCtlMod0(int efd, final int fd, final int flags);
 
     public static void epollCtlDel(int efd, final int fd) throws IOException {
         int res = epollCtlDel0(efd, fd);
         if (res < 0) {
             throw newIOException("epoll_ctl", res);
         }
     }
     private static native int epollCtlDel0(int efd, final int fd);
 
     // File-descriptor operations
     public static int splice(int fd, long offIn, int fdOut, long offOut, long len) throws IOException {
         int res = splice0(fd, offIn, fdOut, offOut, len);
         if (res >= 0) {
             return res;
         }
         return ioResult("splice", res, SPLICE_CONNECTION_RESET_EXCEPTION, SPLICE_CLOSED_CHANNEL_EXCEPTION);
     }
 
     private static native int splice0(int fd, long offIn, int fdOut, long offOut, long len);
 
     public static long sendfile(
             int dest, DefaultFileRegion src, long baseOffset, long offset, long length) throws IOException {
         // Open the file-region as it may be created via the lazy constructor. This is needed as we directly access
         // the FileChannel field directly via JNI
         src.open();
 
         long res = sendfile0(dest, src, baseOffset, offset, length);
         if (res >= 0) {
             return res;
         }
         return ioResult("sendfile", (int) res, SENDFILE_CONNECTION_RESET_EXCEPTION, SENDFILE_CLOSED_CHANNEL_EXCEPTION);
     }
 
     private static native long sendfile0(
             int dest, DefaultFileRegion src, long baseOffset, long offset, long length) throws IOException;
 
     public static int sendmmsg(
             int fd, NativeDatagramPacketArray.NativeDatagramPacket[] msgs, int offset, int len) throws IOException {
         int res = sendmmsg0(fd, msgs, offset, len);
         if (res >= 0) {
             return res;
         }
         return ioResult("sendmmsg", res, SENDMMSG_CONNECTION_RESET_EXCEPTION, SENDMMSG_CLOSED_CHANNEL_EXCEPTION);
     }
 
     private static native int sendmmsg0(
             int fd, NativeDatagramPacketArray.NativeDatagramPacket[] msgs, int offset, int len);
 
     public static int recvFd(int fd) throws IOException {
         int res = recvFd0(fd);
         if (res > 0) {
             return res;
         }
         if (res == 0) {
             return -1;
         }
 
         if (res == ERRNO_EAGAIN_NEGATIVE || res == ERRNO_EWOULDBLOCK_NEGATIVE) {
             // Everything consumed so just return -1 here.
             return 0;
         }
         throw newIOException("recvFd", res);
     }
 
     private static native int recvFd0(int fd);
 
     public static int sendFd(int socketFd, int fd) throws IOException {
         int res = sendFd0(socketFd, fd);
         if (res >= 0) {
             return res;
         }
         if (res == ERRNO_EAGAIN_NEGATIVE || res == ERRNO_EWOULDBLOCK_NEGATIVE) {
             // Everything consumed so just return -1 here.
             return -1;
         }
         throw newIOException("sendFd", res);
     }
 
     private static native int sendFd0(int socketFd, int fd);
 
     // Socket option operations
     public static native int isReuseAddress(int fd) throws IOException;
     public static native int isReusePort(int fd) throws IOException;
     public static native int getTcpNotSentLowAt(int fd) throws IOException;
     public static native int getTrafficClass(int fd) throws IOException;
     public static native int isBroadcast(int fd) throws IOException;
     public static native int getTcpKeepIdle(int fd) throws IOException;
     public static native int getTcpKeepIntvl(int fd) throws IOException;
     public static native int getTcpKeepCnt(int fd) throws IOException;
     public static native int getTcpUserTimeout(int milliseconds) throws IOException;
     public static native int isIpFreeBind(int fd)throws IOException;
 
     public static native void setReuseAddress(int fd, int reuseAddress) throws IOException;
     public static native void setReusePort(int fd, int reuseAddress) throws IOException;
     public static native void setTcpFastopen(int fd, int tcpFastopenBacklog) throws IOException;
     public static native void setTcpNotSentLowAt(int fd, int tcpNotSentLowAt) throws IOException;
     public static native void setTrafficClass(int fd, int tcpNoDelay) throws IOException;
     public static native void setBroadcast(int fd, int broadcast) throws IOException;
     public static native void setTcpKeepIdle(int fd, int seconds) throws IOException;
     public static native void setTcpKeepIntvl(int fd, int seconds) throws IOException;
     public static native void setTcpKeepCnt(int fd, int probes) throws IOException;
     public static native void setTcpUserTimeout(int fd, int milliseconds)throws IOException;
     public static native void setIpFreeBind(int fd, int freeBind) throws IOException;
     public static void tcpInfo(int fd, EpollTcpInfo info) throws IOException {
         tcpInfo0(fd, info.info);
     }
 
     private static native void tcpInfo0(int fd, long[] array) throws IOException;
 
     public static void setTcpMd5Sig(int fd, InetAddress address, byte[] key) throws IOException {
         final NativeInetAddress a = NativeInetAddress.newInstance(address);
         setTcpMd5Sig0(fd, a.address(), a.scopeId(), key);
     }
 
     private static native void setTcpMd5Sig0(int fd, byte[] address, int scopeId, byte[] key) throws IOException;
 
     // epoll_event related
     public static native int sizeofEpollEvent();
     public static native int offsetofEpollData();
 
     private Native() {
         // utility
     }
 
     private static void loadNativeLibrary() {
         String name = SystemPropertyUtil.get("os.name").toLowerCase(Locale.UK).trim();
         if (!name.startsWith("linux")) {
             throw new IllegalStateException("Only supported on Linux");
         }
         String staticLibName = "netty_transport_native_epoll";
         String sharedLibName = staticLibName + '_' + PlatformDependent.normalizedArch();
         ClassLoader cl = PlatformDependent.getClassLoader(Native.class);
         try {
             NativeLibraryLoader.load(sharedLibName, cl);
         } catch (UnsatisfiedLinkError e1) {
             try {
                 NativeLibraryLoader.load(staticLibName, cl);
                 logger.debug("Failed to load {}", sharedLibName, e1);
             } catch (UnsatisfiedLinkError e2) {
                 ThrowableUtil.addSuppressed(e1, e2);
                 throw e1;
             }
         }
     }
 }