package org.codehaus.plexus.components.io.resources;
   
   /*
    * Copyright 2007 The Codehaus Foundation.
    *
    * 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.
   */
  
  import javax.annotation.Nonnull;
  
  import java.io.ByteArrayInputStream;
  import java.io.File;
  import java.io.FileInputStream;
  import java.io.IOException;
  import java.io.InputStream;
  import java.net.URL;
  import java.nio.file.Files;
  import java.nio.file.LinkOption;
  import java.nio.file.attribute.BasicFileAttributes;
  import java.nio.file.attribute.FileTime;
  import java.util.Arrays;
  
  import org.apache.commons.io.IOUtils;
  import org.apache.commons.io.output.DeferredFileOutputStream;
  import org.codehaus.plexus.components.io.attributes.AttributeUtils;
  import org.codehaus.plexus.components.io.attributes.FileAttributes;
  import org.codehaus.plexus.components.io.attributes.PlexusIoResourceAttributes;
  import org.codehaus.plexus.components.io.functions.ContentSupplier;
  import org.codehaus.plexus.components.io.functions.FileSupplier;
  import org.codehaus.plexus.components.io.functions.HardLinkIdentitySupplier;
  import org.codehaus.plexus.components.io.functions.InputStreamTransformer;
  import org.codehaus.plexus.components.io.functions.ResourceAttributeSupplier;
  
  import static java.util.Objects.requireNonNull;
  
  /**
   * Implementation of {@link PlexusIoResource} for files.
   */
  public class PlexusIoFileResource extends AbstractPlexusIoResource
          implements ResourceAttributeSupplier, FileSupplier, HardLinkIdentitySupplier {
  
      @Nonnull
      private final File file;
  
      @Nonnull
      private final PlexusIoResourceAttributes attributes;
  
      @Nonnull
      private final FileAttributes fileAttributes;
  
      private final ContentSupplier contentSupplier;
  
      private final boolean originalContent;
  
      private final DeferredFileOutputStream dfos;
  
      protected PlexusIoFileResource(@Nonnull File file, @Nonnull String name, @Nonnull PlexusIoResourceAttributes attrs)
              throws IOException {
          this(file, name, attrs, null, null);
      }
  
      PlexusIoFileResource(
              @Nonnull final File file,
              @Nonnull String name,
              @Nonnull PlexusIoResourceAttributes attrs,
              final ContentSupplier contentSupplier,
              final InputStreamTransformer streamTransformer)
              throws IOException {
          this(file, name, attrs, new FileAttributes(file, true), contentSupplier, streamTransformer);
      }
  
      PlexusIoFileResource(
              @Nonnull final File file,
              @Nonnull String name,
              @Nonnull PlexusIoResourceAttributes attrs,
              @Nonnull FileAttributes fileAttributes,
              final ContentSupplier contentSupplier,
              final InputStreamTransformer streamTransformer)
              throws IOException {
          super(
                  name,
                  fileAttributes.getLastModifiedTime().toMillis(),
                  fileAttributes.getSize(),
                  fileAttributes.isRegularFile(),
                  fileAttributes.isDirectory(),
                  fileAttributes.isRegularFile()
                          || fileAttributes.isDirectory()
                          || fileAttributes.isSymbolicLink()
                          || fileAttributes.isOther());
         this.file = file;
         this.attributes = requireNonNull(attrs, "attributes is null for file " + file.getName());
         this.fileAttributes = requireNonNull(fileAttributes, "fileAttributes is null for file " + file.getName());
         this.contentSupplier = contentSupplier != null ? contentSupplier : getRootContentSupplier(file);
 
         boolean hasTransformer = streamTransformer != null && streamTransformer != identityTransformer;
         InputStreamTransformer transToUse = streamTransformer != null ? streamTransformer : identityTransformer;
 
         originalContent = contentSupplier == null && !hasTransformer;
 
         dfos = hasTransformer && file.isFile() ? asDeferredStream(this.contentSupplier, transToUse, this) : null;
     }
 
     private static DeferredFileOutputStream asDeferredStream(
             @Nonnull ContentSupplier supplier, @Nonnull InputStreamTransformer transToUse, PlexusIoResource resource)
             throws IOException {
         DeferredFileOutputStream dfos = DeferredFileOutputStream.builder()
                 .setThreshold(5000000)
                 .setPrefix("p-archiver")
                 .get();
         try (InputStream inputStream = supplier.getContents();
                 InputStream transformed = transToUse.transform(resource, inputStream);
                 DeferredFileOutputStream closeable = dfos) {
             IOUtils.copy(transformed, dfos);
         }
         return dfos;
     }
 
     private static ContentSupplier getRootContentSupplier(final File file) {
         return () -> Files.newInputStream(file.toPath());
     }
 
     public static String getName(File file) {
         return file.getPath().replace('\\', '/');
     }
 
     /**
      * Returns the resource file.
      */
     @Nonnull
     public File getFile() {
         return file;
     }
 
     @Nonnull
     public InputStream getContents() throws IOException {
         if (dfos == null) {
             return contentSupplier.getContents();
         }
         if (dfos.isInMemory()) {
             return new ByteArrayInputStream(dfos.getData());
         } else {
             return new FileInputStream(dfos.getFile()) {
                 @SuppressWarnings("ResultOfMethodCallIgnored")
                 @Override
                 public void close() throws IOException {
                     super.close();
                     dfos.getFile().delete();
                 }
             };
         }
     }
 
     @Nonnull
     public URL getURL() throws IOException {
         return getFile().toURI().toURL();
     }
 
     public long getSize() {
         if (dfos == null) {
             return fileAttributes.getSize();
         }
         if (dfos.isInMemory()) {
             return dfos.getByteCount();
         } else {
             return dfos.getFile().length();
         }
     }
 
     public boolean isDirectory() {
         return fileAttributes.isDirectory();
     }
 
     public boolean isExisting() {
         if (attributes instanceof FileAttributes) {
             return true;
         }
         return getFile().exists();
     }
 
     public boolean isFile() {
         return fileAttributes.isRegularFile();
     }
 
     @Nonnull
     public PlexusIoResourceAttributes getAttributes() {
         return attributes;
     }
 
     @Nonnull
     public FileAttributes getFileAttributes() {
         return fileAttributes;
     }
 
     public long getLastModified() {
         FileTime lastModified = fileAttributes.getLastModifiedTime();
         if (lastModified != null) {
             return lastModified.toMillis();
         }
         return AttributeUtils.getLastModified(getFile());
     }
 
     @Override
     public boolean isSymbolicLink() {
         return getAttributes().isSymbolicLink();
     }
 
     /**
      * Identifies an untransformed regular file without following symbolic links.
      * Subclasses that change content must explicitly supply their own guarantee.
      *
      * @return a filesystem-scoped file identity, or null for unknown content
      * @throws IOException if the file attributes cannot be read
      */
     @Override
     public Object getHardLinkIdentity() throws IOException {
         // A backing file alone does not describe custom suppliers or transformed bytes.
         if (!originalContent || getClass() != PlexusIoFileResource.class) {
             return null;
         }
         BasicFileAttributes attrs =
                 Files.readAttributes(file.toPath(), BasicFileAttributes.class, LinkOption.NOFOLLOW_LINKS);
         if (!attrs.isRegularFile() || attrs.fileKey() == null) {
             return null;
         }
         // Include the observed content version so a changed source cannot reuse an old payload.
         return Arrays.asList(file.toPath().getFileSystem(), attrs.fileKey(), attrs.size(), attrs.lastModifiedTime());
     }
 
     protected DeferredFileOutputStream getDfos() {
         return dfos;
     }
 
     private static final InputStreamTransformer identityTransformer =
             AbstractPlexusIoResourceCollection.identityTransformer;
 }