/*
    * junixsocket
    *
    * Copyright 2009-2024 Christian Kohlschütter
    *
    * Licensed 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 org.newsclub.net.unix;
  
  import java.io.Closeable;
  import java.io.FileDescriptor;
  import java.io.IOException;
  import java.nio.ByteBuffer;
  import java.nio.channels.Pipe;
  import java.nio.channels.spi.SelectorProvider;
  
  import com.kohlschutter.annotations.compiletime.SuppressFBWarnings;
  
  /**
   * A {@link Pipe}, natively implemented.
   *
   * @author Christian Kohlschütter
   */
  public final class AFPipe extends Pipe implements Closeable {
    static final AFSupplier<Integer> DUMMY_TIMEOUT = () -> 0; // wait forever
    private final AFCore sourceCore;
    private final AFCore sinkCore;
    private final SourceChannel sourceChannel;
    private final SinkChannel sinkChannel;
    private final int options;
  
    AFPipe(AFSelectorProvider<?> provider, boolean selectable) throws IOException {
      super();
  
      NativeUnixSocket.ensureSupported();
  
      this.sourceCore = new AFCore(this, (FileDescriptor) null);
      this.sinkCore = new AFCore(this, (FileDescriptor) null);
  
      boolean isSocket = NativeUnixSocket.initPipe(sourceCore.fd, sinkCore.fd, selectable);
      this.options = isSocket ? 0 : NativeUnixSocket.OPT_NON_SOCKET;
  
      this.sourceChannel = new SourceChannel(provider);
      this.sinkChannel = new SinkChannel(provider);
    }
  
    @SuppressFBWarnings("EI_EXPOSE_REP")
    @Override
    public SourceChannel source() {
      return sourceChannel;
    }
  
    @SuppressFBWarnings("EI_EXPOSE_REP")
    @Override
    public SinkChannel sink() {
      return sinkChannel;
    }
  
    FileDescriptor sourceFD() {
      return sourceCore.fd;
    }
  
    FileDescriptor sinkFD() {
      return sinkCore.fd;
    }
  
    @Override
    public void close() throws IOException {
      try { // NOPMD.UseTryWithResources
        source().close();
      } finally {
        sink().close();
      }
    }
  
    /**
     * A channel representing the readable end of a {@link Pipe}, with access to the
     * {@link FileDescriptor}.
     */
    public final class SourceChannel extends java.nio.channels.Pipe.SourceChannel implements
        FileDescriptorAccess {
      SourceChannel(SelectorProvider provider) {
        super(provider);
      }
  
      @Override
      public long read(ByteBuffer[] dsts, int offset, int length) throws IOException {
        if (length == 0) {
          return 0;
       }
       return read(dsts[offset]);
     }
 
     @Override
     public long read(ByteBuffer[] dsts) throws IOException {
       return read(dsts, 0, dsts.length);
     }
 
     @Override
     public int read(ByteBuffer dst) throws IOException {
       return sourceCore.read(dst, DUMMY_TIMEOUT, null, options);
     }
 
     @Override
     protected void implConfigureBlocking(boolean block) throws IOException {
       sourceCore.implConfigureBlocking(block);
     }
 
     @Override
     protected void implCloseSelectableChannel() throws IOException {
       sourceCore.close();
     }
 
     @Override
     public FileDescriptor getFileDescriptor() throws IOException {
       return sourceCore.fd;
     }
   }
 
   /**
    * A channel representing the writable end of a {@link Pipe}, with access to the
    * {@link FileDescriptor}.
    */
   public final class SinkChannel extends java.nio.channels.Pipe.SinkChannel implements
       FileDescriptorAccess {
     SinkChannel(SelectorProvider provider) {
       super(provider);
     }
 
     @Override
     public long write(ByteBuffer[] srcs, int offset, int length) throws IOException {
       if (length == 0) {
         return 0;
       }
       return write(srcs[offset]);
     }
 
     @Override
     public long write(ByteBuffer[] srcs) throws IOException {
       return write(srcs, 0, srcs.length);
     }
 
     @Override
     public int write(ByteBuffer src) throws IOException {
       return sinkCore.write(src, DUMMY_TIMEOUT, null, options);
     }
 
     @Override
     protected void implConfigureBlocking(boolean block) throws IOException {
       sinkCore.implConfigureBlocking(block);
     }
 
     @Override
     protected void implCloseSelectableChannel() throws IOException {
       sinkCore.close();
     }
 
     @Override
     public FileDescriptor getFileDescriptor() throws IOException {
       return sinkCore.fd;
     }
   }
 
   /**
    * Returns the options bitmask that is to be passed to native receive/send calls.
    *
    * @return The options.
    */
   int getOptions() {
     return options;
   }
 
   /**
    * Opens an {@link AFPipe}.
    *
    * @return The new pipe
    * @throws IOException on error.
    */
   public static AFPipe open() throws IOException {
     return AFUNIXSelectorProvider.provider().openPipe();
   }
 }