/*
 * Copyright 2009 Google Inc.
 * 
 * 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 com.google.gwt.user.linker.rpc;

import com.google.gwt.core.ext.TreeLogger;
import com.google.gwt.core.ext.linker.Artifact;
import com.google.gwt.dev.util.DiskCache;
import com.google.gwt.dev.util.Util;

import java.io.ByteArrayInputStream;
import java.io.ByteArrayOutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.ObjectInputStream;
import java.io.ObjectOutputStream;

/**
 * This artifact holds a log of the reasoning for which types are considered
 * serializable for a particular RPC interface.
 */
public class RpcLogArtifact extends Artifact<RpcLogArtifact> {
  /**
   * This strong name indicates that the artifact doesn't really have its own
   * strong name.
   */
  public static final String UNSPECIFIED_STRONGNAME = "UNSPECIFIED";
  private static DiskCache diskCache = new DiskCache();

  private long diskCacheToken;
  private final String qualifiedSourceName;
  private final String serializationPolicyStrongName;

  public RpcLogArtifact(String qualifiedSourceName,
      String serializationPolicyStrongName, String rpcLog) {
    super(RpcLogLinker.class);
    this.qualifiedSourceName = qualifiedSourceName;
    this.serializationPolicyStrongName = serializationPolicyStrongName;
    diskCacheToken = diskCache.writeString(rpcLog);
  }

  /**
   * @param logger a TreeLogger
   */
  public InputStream getContents(TreeLogger logger) {
    return new ByteArrayInputStream(diskCache.readByteArray(diskCacheToken));
  }

  public String getQualifiedSourceName() {
    return qualifiedSourceName;
  }

  public String getSerializationPolicyStrongName() {
    return serializationPolicyStrongName;
  }

  @Override
  public int hashCode() {
    return serializationPolicyStrongName.hashCode();
  }

  @Override
  protected int compareToComparableArtifact(RpcLogArtifact o) {
    int comp;
    comp = qualifiedSourceName.compareTo(o.getQualifiedSourceName());
    if (comp != 0) {
      return comp;
    }
    return serializationPolicyStrongName.compareTo(o.getSerializationPolicyStrongName());
  }

  @Override
  protected Class<RpcLogArtifact> getComparableArtifactType() {
    return RpcLogArtifact.class;
  }

  private void readObject(ObjectInputStream stream) throws IOException,
      ClassNotFoundException {
    stream.defaultReadObject();
    ByteArrayOutputStream baos = new ByteArrayOutputStream();
    Util.copyNoClose(stream, baos);
    diskCacheToken = diskCache.writeByteArray(baos.toByteArray());
  }

  private void writeObject(ObjectOutputStream stream) throws IOException {
    stream.defaultWriteObject();
    diskCache.transferToStream(diskCacheToken, stream);
  }
}