gecko-dev/xpcom/base/nsIGZFileWriter.idl

/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
/* vim: set ts=8 sts=2 et sw=2 tw=80: */
/* This Source Code Form is subject to the terms of the Mozilla Public
 * License, v. 2.0. If a copy of the MPL was not distributed with this
 * file, You can obtain one at http://mozilla.org/MPL/2.0/. */

#include "nsISupports.idl"

%{C++
#include "nsDependentString.h"
#include <stdio.h>
%}

interface nsIFile;
[ptr] native FILE(FILE);

/**
 * A simple interface for writing to a .gz file.
 *
 * Note that the file that this interface produces has a different format than
 * what you'd get if you compressed your data as a gzip stream and dumped the
 * result to a file.
 *
 * The standard gunzip tool cannot decompress a raw gzip stream, but can handle
 * the files produced by this interface.
 */
[scriptable, uuid(6bd5642c-1b90-4499-ba4b-199f27efaba5)]
interface nsIGZFileWriter : nsISupports
{
  /**
   * Initialize this object.  We'll write our gzip'ed data to the given file,
   * overwriting its contents if the file exists.
   *
   * init() will return an error if called twice.  It's an error to call any
   * other method on this interface without first calling init().
   */
  void init(in nsIFile file);

  /**
   * Alternate version of init() for use when the file is already opened;
   * e.g., with a FileDescriptor passed over IPC.
   */
  [noscript] void initANSIFileDesc(in FILE file);

  /**
   * Write the given string to the file.
   */
  void write(in AUTF8String str);

  /*
   * The following two overloads of Write() are C++ because we can't overload
   * methods in XPIDL.  Anyway, they don't add much functionality for JS
   * callers.
   */
  %{C++
  /**
   * Write the given char* to the file (not including the null-terminator).
   */
  nsresult Write(const char* str)
  {
    return Write(str, strlen(str));
  }

  /**
   * Write |length| bytes of |str| to the file.
   */
  nsresult Write(const char* str, uint32_t len)
  {
    return Write(nsDependentCString(str, len));
  }
  %}

  /**
   * Close this nsIGZFileWriter.  Classes implementing nsIGZFileWriter will run
   * this method when the underlying object is destroyed, so it's not strictly
   * necessary to explicitly call it from your code.
   *
   * It's an error to call this method twice, and it's an error to call write()
   * after finish() has been called.
   */
  void finish();
};