// Protocol Buffers - Google's data interchange format
// Copyright 2008 Google Inc.  All rights reserved.
//
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file or at
// https://developers.google.com/open-source/licenses/bsd

package com.google.protobuf;

import java.io.IOException;

/**
 * Thrown when a protocol message being parsed is invalid in some way. For instance,
 * it contains a malformed varint or a negative byte length.
 *
 * @author kenton@google.com Kenton Varda
 */
public class InvalidProtocolBufferException extends IOException {
  private static final long serialVersionUID = -1616151763072450476L;
  private MessageLite unfinishedMessage = null;
  private boolean wasThrownFromInputStream;

  public InvalidProtocolBufferException(String description) {
    super(description);
  }

  public InvalidProtocolBufferException(Exception e) {
    super(e.getMessage(), e);
  }

  public InvalidProtocolBufferException(String description, Exception e) {
    super(description, e);
  }

  public InvalidProtocolBufferException(IOException e) {
    super(e.getMessage(), e);
  }

  public InvalidProtocolBufferException(String description, IOException e) {
    super(description, e);
  }

  /**
   * Attaches an unfinished message to the exception to support best-effort parsing in {@code
   * Parser} interface.
   *
   * @return this
   */
  public InvalidProtocolBufferException setUnfinishedMessage(MessageLite unfinishedMessage) {
    this.unfinishedMessage = unfinishedMessage;
    return this;
  }

  /**
   * Returns the unfinished message attached to the exception, or null if no message is attached.
   */
  public MessageLite getUnfinishedMessage() {
    return unfinishedMessage;
  }

  /** Set by CodedInputStream */
  void setThrownFromInputStream() {
    /* This write can be racy if the same exception is stored and then thrown by multiple custom
     * InputStreams on different threads. But since it only ever moves from false->true, there's no
     * problem. A thread checking this condition after catching this exception from a delegate
     * stream of CodedInputStream is guaranteed to always observe true, because a write on the same
     * thread set the value when the exception left the delegate. A thread checking the same
     * condition with an exception created by CodedInputStream is guaranteed to always see false,
     * because the exception has not been exposed to any code that could publish it to other threads
     * and cause a write.
     */
    wasThrownFromInputStream = true;
  }

  /**
   * Allows code catching IOException from CodedInputStream to tell whether this instance was thrown
   * by a delegate InputStream, rather than directly by a parse failure.
   */
  boolean getThrownFromInputStream() {
    return wasThrownFromInputStream;
  }

  /**
   * Unwraps the underlying {@link IOException} if this exception was caused by an I/O problem.
   * Otherwise, returns {@code this}.
   */
  public IOException unwrapIOException() {
    return getCause() instanceof IOException ? (IOException) getCause() : this;
  }

  static InvalidProtocolBufferException truncatedMessage() {
    return new InvalidProtocolBufferException(
        "While parsing a protocol message, the input ended unexpectedly "
            + "in the middle of a field.  This could mean either that the "
            + "input has been truncated or that an embedded message "
            + "misreported its own length.");
  }

  static InvalidProtocolBufferException negativeSize() {
    return new InvalidProtocolBufferException(
        "CodedInputStream encountered an embedded string or message "
            + "which claimed to have negative size.");
  }

  static InvalidProtocolBufferException malformedVarint() {
    return new InvalidProtocolBufferException("CodedInputStream encountered a malformed varint.");
  }

  static InvalidProtocolBufferException invalidTag() {
    return new InvalidProtocolBufferException("Protocol message contained an invalid tag (zero).");
  }

  static InvalidProtocolBufferException invalidEndTag() {
    return new InvalidProtocolBufferException(
        "Protocol message end-group tag did not match expected tag.");
  }

  static InvalidWireTypeException invalidWireType() {
    return new InvalidWireTypeException("Protocol message tag had invalid wire type.");
  }

  /** Exception indicating that an unexpected wire type was encountered for a field. */
  @ExperimentalApi
  public static class InvalidWireTypeException extends InvalidProtocolBufferException {
    private static final long serialVersionUID = 3283890091615336259L;

    public InvalidWireTypeException(String description) {
      super(description);
    }
  }

  static InvalidProtocolBufferException recursionLimitExceeded() {
    return new InvalidProtocolBufferException(
        "Protocol message had too many levels of nesting.  May be malicious.  "
            + "Use setRecursionLimit() to increase the recursion depth limit.");
  }

  static InvalidProtocolBufferException sizeLimitExceeded() {
    return new InvalidProtocolBufferException(
        "Protocol message was too large.  May be malicious.  Use CodedInputStream.setSizeLimit() to"
            + " increase the size limit. If reading multiple messages, consider resetting the"
            + " counter between each message using CodedInputStream.resetSizeCounter().");
  }

  static InvalidProtocolBufferException parseFailure() {
    return new InvalidProtocolBufferException("Failed to parse the message.");
  }

  static InvalidProtocolBufferException invalidUtf8() {
    return new InvalidProtocolBufferException("Protocol message had invalid UTF-8.");
  }
}
