content: /*
   * Copyright (c) 2009, 2019, 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.
   */
  
  package openjdk.tools.javac.file;
  
  import java.io.IOException;
  import java.io.InputStream;
  import java.lang.ref.SoftReference;
  import java.lang.reflect.Constructor;
  import java.net.URL;
  import java.net.URLClassLoader;
  import java.nio.ByteBuffer;
  import java.nio.CharBuffer;
  import java.nio.charset.Charset;
  import java.nio.charset.CharsetDecoder;
  import java.nio.charset.CoderResult;
  import java.nio.charset.CodingErrorAction;
  import java.nio.charset.IllegalCharsetNameException;
  import java.nio.charset.UnsupportedCharsetException;
  import java.nio.file.Path;
  import java.util.Collection;
  import java.util.HashMap;
  import java.util.HashSet;
  import java.util.Iterator;
  import java.util.Map;
  import java.util.Objects;
  import java.util.Set;
  
  import jdkx.tools.JavaFileManager;
  import jdkx.tools.JavaFileObject;
  import jdkx.tools.JavaFileObject.Kind;
  
  import openjdk.tools.javac.main.Option;
  import openjdk.tools.javac.main.OptionHelper;
  import openjdk.tools.javac.main.OptionHelper.GrumpyHelper;
  import openjdk.tools.javac.resources.CompilerProperties.Errors;
  import openjdk.tools.javac.util.Context;
  import openjdk.tools.javac.util.DefinedBy;
  import openjdk.tools.javac.util.DefinedBy.Api;
  import openjdk.tools.javac.util.Log;
  import openjdk.tools.javac.util.Options;
  
  /**
   * Utility methods for building a file manager.
   * There are no references here to file-system specific objects such as
   * java.io.File or java.nio.file.Path.
   */
  public abstract class BaseFileManager implements JavaFileManager {
      protected BaseFileManager(Charset charset) {
          this.charset = charset;
          byteBufferCache = new ByteBufferCache();
          locations = createLocations();
      }
  
      /**
       * Set the context for JavacPathFileManager.
       * @param context the context containing items to be associated with the file manager
       */
      public void setContext(Context context) {
          log = Log.instance(context);
          options = Options.instance(context);
          classLoaderClass = options.get("procloader");
  
          // Avoid initializing Lint
          boolean warn = options.isLintSet("path");
          locations.update(log, warn, FSInfo.instance(context));
  
          // Setting this option is an indication that close() should defer actually closing
          // the file manager until after a specified period of inactivity.
          // This is to accommodate clients which save references to Symbols created for use
          // within doclets or annotation processors, and which then attempt to use those
          // references after the tool exits, having closed any internally managed file manager.
          // Ideally, such clients should run the tool via the jdkx.tools API, providing their
          // own file manager, which can be closed by the client when all use of that file
          // manager is complete.
          // If the option has a numeric value, it will be interpreted as the duration,
          // in seconds, of the period of inactivity to wait for, before the file manager
          // is actually closed.
          // See also deferredClose().
          String s = options.get("fileManager.deferClose");
          if (s != null) {
              try {
                  deferredCloseTimeout = (int) (Float.parseFloat(s) * 1000);
              } catch (NumberFormatException e) {
                  deferredCloseTimeout = 60 * 1000;  // default: one minute, in millis
              }
          }
      }
  
      protected Locations createLocations() {
          return new Locations();
      }
  
      /**
       * The log to be used for error reporting.
       */
      public Log log;
  
      /**
       * User provided charset (through jdkx.tools).
       */
      protected Charset charset;
  
      protected Options options;
  
      protected String classLoaderClass;
  
      protected final Locations locations;
  
      /**
       * A flag for clients to use to indicate that this file manager should
       * be closed when it is no longer required.
       */
      public boolean autoClose;
  
      /**
       * Wait for a period of inactivity before calling close().
       * The length of the period of inactivity is given by {@code deferredCloseTimeout}
       */
      protected void deferredClose() {
          Thread t = new Thread(getClass().getName() + " DeferredClose") {
              @Override
              public void run() {
                  try {
                      synchronized (BaseFileManager.this) {
                          long now = System.currentTimeMillis();
                          while (now < lastUsedTime + deferredCloseTimeout) {
                              BaseFileManager.this.wait(lastUsedTime + deferredCloseTimeout - now);
                              now = System.currentTimeMillis();
                          }
                          deferredCloseTimeout = 0;
                          close();
                      }
                  } catch (InterruptedException e) {
                  } catch (IOException e) {
                  }
              }
          };
          t.setDaemon(true);
          t.start();
      }
  
      synchronized void updateLastUsedTime() {
          if (deferredCloseTimeout > 0) { // avoid updating the time unnecessarily
              lastUsedTime = System.currentTimeMillis();
          }
      }
  
      private long lastUsedTime = System.currentTimeMillis();
      protected long deferredCloseTimeout = 0;
  
      public void clear() {
          new HashSet<>(options.keySet()).forEach(k -> options.remove(k));
      }
  
      protected ClassLoader getClassLoader(URL[] urls) {
          ClassLoader thisClassLoader = getClass().getClassLoader();
  
          // Allow the following to specify a closeable classloader
          // other than URLClassLoader.
  
          // 1: Allow client to specify the class to use via hidden option
          if (classLoaderClass != null) {
              try {
                  Class<? extends ClassLoader> loader =
                          Class.forName(classLoaderClass).asSubclass(ClassLoader.class);
                  Class<?>[] constrArgTypes = { URL[].class, ClassLoader.class };
                  Constructor<? extends ClassLoader> constr = loader.getConstructor(constrArgTypes);
                  return constr.newInstance(urls, thisClassLoader);
              } catch (ReflectiveOperationException t) {
                  // ignore errors loading user-provided class loader, fall through
              }
          }
          return new URLClassLoader(urls, thisClassLoader);
      }
  
      public boolean isDefaultBootClassPath() {
          return locations.isDefaultBootClassPath();
      }
  
      public boolean isDefaultSystemModulesPath() {
          return locations.isDefaultSystemModulesPath();
      }
  
      // <editor-fold defaultstate="collapsed" desc="Option handling">
      @Override @DefinedBy(Api.COMPILER)
      public boolean handleOption(String current, Iterator<String> remaining) {
          OptionHelper helper = new GrumpyHelper(log) {
              @Override
              public String get(Option option) {
                  return options.get(option);
              }
  
              @Override
              public void put(String name, String value) {
                  options.put(name, value);
              }
  
              @Override
              public void remove(String name) {
                  options.remove(name);
              }
  
              @Override
              public boolean handleFileManagerOption(Option option, String value) {
                  return handleOption(option, value);
              }
          };
  
          Option o = Option.lookup(current, javacFileManagerOptions);
          if (o == null) {
              return false;
          }
  
          try {
              o.handleOption(helper, current, remaining);
          } catch (Option.InvalidValueException e) {
              throw new IllegalArgumentException(e.getMessage(), e);
          }
  
          return true;
      }
      // where
          protected static final Set<Option> javacFileManagerOptions =
              Option.getJavacFileManagerOptions();
  
      @Override @DefinedBy(Api.COMPILER)
      public int isSupportedOption(String option) {
          Option o = Option.lookup(option, javacFileManagerOptions);
          return (o == null) ? -1 : o.hasArg() ? 1 : 0;
      }
  
      protected String multiReleaseValue;
  
      /**
       * Common back end for OptionHelper handleFileManagerOption.
       * @param option the option whose value to be set
       * @param value the value for the option
       * @return true if successful, and false otherwise
       */
      public boolean handleOption(Option option, String value) {
          switch (option) {
              case ENCODING:
                  encodingName = value;
                  return true;
  
              case MULTIRELEASE:
                  multiReleaseValue = value;
                  locations.setMultiReleaseValue(value);
                  return true;
  
              default:
                  return locations.handleOption(option, value);
          }
      }
  
      /**
       * Call handleOption for collection of options and corresponding values.
       * @param map a collection of options and corresponding values
       * @return true if all the calls are successful
       */
      public boolean handleOptions(Map<Option, String> map) {
          boolean ok = true;
          for (Map.Entry<Option, String> e: map.entrySet()) {
              try {
                  ok = ok & handleOption(e.getKey(), e.getValue());
              } catch (IllegalArgumentException ex) {
                  log.error(Errors.IllegalArgumentForOption(e.getKey().getPrimaryName(), ex.getMessage()));
                  ok = false;
              }
          }
          return ok;
      }
  
      // </editor-fold>
  
      // <editor-fold defaultstate="collapsed" desc="Encoding">
      private String encodingName;
      private String defaultEncodingName;
      private String getDefaultEncodingName() {
          if (defaultEncodingName == null) {
              defaultEncodingName = Charset.defaultCharset().name();
          }
          return defaultEncodingName;
      }
  
      public String getEncodingName() {
          return (encodingName != null) ? encodingName : getDefaultEncodingName();
      }
  
      @SuppressWarnings("cast")
      public CharBuffer decode(ByteBuffer inbuf, boolean ignoreEncodingErrors) {
          String encName = getEncodingName();
          CharsetDecoder decoder;
          try {
              decoder = getDecoder(encName, ignoreEncodingErrors);
          } catch (IllegalCharsetNameException | UnsupportedCharsetException e) {
              log.error(Errors.UnsupportedEncoding(encName));
              return (CharBuffer)CharBuffer.allocate(1).flip();
          }
  
          // slightly overestimate the buffer size to avoid reallocation.
          float factor =
              decoder.averageCharsPerByte() * 0.8f +
              decoder.maxCharsPerByte() * 0.2f;
          CharBuffer dest = CharBuffer.
              allocate(10 + (int)(inbuf.remaining()*factor));
  
          while (true) {
              CoderResult result = decoder.decode(inbuf, dest, true);
              dest.flip();
  
              if (result.isUnderflow()) { // done reading
                  // make sure there is at least one extra character
                  if (dest.limit() == dest.capacity()) {
                      dest = CharBuffer.allocate(dest.capacity()+1).put(dest);
                      dest.flip();
                  }
                  return dest;
              } else if (result.isOverflow()) { // buffer too small; expand
                  int newCapacity =
                      10 + dest.capacity() +
                      (int)(inbuf.remaining()*decoder.maxCharsPerByte());
                  dest = CharBuffer.allocate(newCapacity).put(dest);
              } else if (result.isMalformed() || result.isUnmappable()) {
                  // bad character in input
                  StringBuilder unmappable = new StringBuilder();
                  int len = result.length();
  
                  for (int i = 0; i < len; i++) {
                      unmappable.append(String.format("%02X", inbuf.get()));
                  }
  
                  String charsetName = charset == null ? encName : charset.name();
  
                  log.error(dest.limit(),
                            Errors.IllegalCharForEncoding(unmappable.toString(), charsetName));
  
                  // undo the flip() to prepare the output buffer
                  // for more translation
                  dest.position(dest.limit());
                  dest.limit(dest.capacity());
                  dest.put((char)0xfffd); // backward compatible
              } else {
                  throw new AssertionError(result);
              }
          }
          // unreached
      }
  
      public CharsetDecoder getDecoder(String encodingName, boolean ignoreEncodingErrors) {
          Charset cs = (this.charset == null)
              ? Charset.forName(encodingName)
              : this.charset;
          CharsetDecoder decoder = cs.newDecoder();
  
          CodingErrorAction action;
          if (ignoreEncodingErrors)
              action = CodingErrorAction.REPLACE;
          else
              action = CodingErrorAction.REPORT;
  
          return decoder
              .onMalformedInput(action)
              .onUnmappableCharacter(action);
      }
      // </editor-fold>
  
      // <editor-fold defaultstate="collapsed" desc="ByteBuffers">
      /**
       * Make a byte buffer from an input stream.
       * @param in the stream
       * @return a byte buffer containing the contents of the stream
       * @throws IOException if an error occurred while reading the stream
       */
      @SuppressWarnings("cast")
      public ByteBuffer makeByteBuffer(InputStream in)
          throws IOException {
          int limit = in.available();
          if (limit < 1024) limit = 1024;
          ByteBuffer result = byteBufferCache.get(limit);
          int position = 0;
          while (in.available() != 0) {
              if (position >= limit)
                  // expand buffer
                  result = ByteBuffer.
                      allocate(limit <<= 1).
                      put((ByteBuffer)result.flip());
              int count = in.read(result.array(),
                  position,
                  limit - position);
              if (count < 0) break;
              result.position(position += count);
          }
          return (ByteBuffer)result.flip();
      }
  
      public void recycleByteBuffer(ByteBuffer bb) {
          byteBufferCache.put(bb);
      }
  
      /**
       * A single-element cache of direct byte buffers.
       */
      @SuppressWarnings("cast")
      private static class ByteBufferCache {
          private ByteBuffer cached;
          ByteBuffer get(int capacity) {
              if (capacity < 20480) capacity = 20480;
              ByteBuffer result =
                  (cached != null && cached.capacity() >= capacity)
                  ? (ByteBuffer)cached.clear()
                  : ByteBuffer.allocate(capacity + capacity>>1);
              cached = null;
              return result;
          }
          void put(ByteBuffer x) {
              cached = x;
          }
      }
  
      private final ByteBufferCache byteBufferCache;
      // </editor-fold>
  
      // <editor-fold defaultstate="collapsed" desc="Content cache">
      public CharBuffer getCachedContent(JavaFileObject file) {
          ContentCacheEntry e = contentCache.get(file);
          if (e == null)
              return null;
  
          if (!e.isValid(file)) {
              contentCache.remove(file);
              return null;
          }
  
          return e.getValue();
      }
  
      public void cache(JavaFileObject file, CharBuffer cb) {
          contentCache.put(file, new ContentCacheEntry(file, cb));
      }
  
      public void flushCache(JavaFileObject file) {
          contentCache.remove(file);
      }
  
      protected final Map<JavaFileObject, ContentCacheEntry> contentCache = new HashMap<>();
  
      protected static class ContentCacheEntry {
          final long timestamp;
          final SoftReference<CharBuffer> ref;
  
          ContentCacheEntry(JavaFileObject file, CharBuffer cb) {
              this.timestamp = file.getLastModified();
              this.ref = new SoftReference<>(cb);
          }
  
          boolean isValid(JavaFileObject file) {
              return timestamp == file.getLastModified();
          }
  
          CharBuffer getValue() {
              return ref.get();
          }
      }
      // </editor-fold>
  
      public static Kind getKind(Path path) {
          return getKind(path.getFileName().toString());
      }
  
      public static Kind getKind(String name) {
          if (name.endsWith(Kind.CLASS.extension))
              return Kind.CLASS;
          else if (name.endsWith(Kind.SOURCE.extension))
              return Kind.SOURCE;
          else if (name.endsWith(Kind.HTML.extension))
              return Kind.HTML;
          else
              return Kind.OTHER;
      }
  
      protected static <T> T nullCheck(T o) {
          return Objects.requireNonNull(o);
      }
  
      protected static <T> Collection<T> nullCheck(Collection<T> it) {
          for (T t : it)
              Objects.requireNonNull(t);
          return it;
      }
  }
  