/* 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/. */

/**
 * This module defines the thread-agnostic components of the Unix version
 * of OS.File. It depends on the thread-agnostic cross-platform components
 * of OS.File.
 *
 * It serves the following purposes:
 * - open libc;
 * - define OS.Unix.Error;
 * - define a few constants and types that need to be defined on all platforms.
 *
 * This module can be:
 * - opened from the main thread as a jsm module;
 * - opened from a chrome worker through importScripts.
 */

if (typeof Components != "undefined") {
  // Module is opened as a jsm module
  this.EXPORTED_SYMBOLS = ["OS"];
  Components.utils.import("resource://gre/modules/ctypes.jsm");
  Components.utils.import("resource://gre/modules/osfile/osfile_shared_allthreads.jsm", this);
}

(function(exports) {
  "use strict";
  if (!exports.OS || !exports.OS.Shared) {
    throw new Error("osfile_unix_allthreads.jsm must be loaded after osfile_shared_allthreads.jsm");
  }
  if (exports.OS.Shared.Unix) {
    // Avoid double inclusion
    return;
  }
  exports.OS.Shared.Unix = {};

  let LOG = OS.Shared.LOG.bind(OS.Shared, "Unix", "allthreads");

  // Open libc
  let libc;
  let libc_candidates =  [ "libSystem.B.dylib",
                           "libc.so.6",
                           "libc.so" ];
  for (let i = 0; i < libc_candidates.length; ++i) {
    try {
      libc = ctypes.open(libc_candidates[i]);
      break;
    } catch (x) {
      LOG("Could not open libc ", libc_candidates[i]);
    }
  }
  if (!libc) {
    throw new Error("Could not open any libc.");
  }
  exports.OS.Shared.Unix.libc = libc;

  // Define declareFFI
  let declareFFI = OS.Shared.declareFFI.bind(null, libc);
  exports.OS.Shared.Unix.declareFFI = declareFFI;

  // Define Error
  let strerror = libc.declare("strerror",
    ctypes.default_abi,
    /*return*/ ctypes.char.ptr,
    /*errnum*/ ctypes.int);

  /**
   * A File-related error.
   *
   * To obtain a human-readable error message, use method |toString|.
   * To determine the cause of the error, use the various |becauseX|
   * getters. To determine the operation that failed, use field
   * |operation|.
   *
   * Additionally, this implementation offers a field
   * |unixErrno|, which holds the OS-specific error
   * constant. If you need this level of detail, you may match the value
   * of this field against the error constants of |OS.Constants.libc|.
   *
   * @param {string=} operation The operation that failed. If unspecified,
   * the name of the calling function is taken to be the operation that
   * failed.
   * @param {number=} lastError The OS-specific constant detailing the
   * reason of the error. If unspecified, this is fetched from the system
   * status.
   *
   * @constructor
   * @extends {OS.Shared.Error}
   */
  let OSError = function OSError(operation, errno) {
    operation = operation || "unknown operation";
    exports.OS.Shared.Error.call(this, operation);
    this.unixErrno = errno || ctypes.errno;
  };
  OSError.prototype = new exports.OS.Shared.Error();
  OSError.prototype.toString = function toString() {
    return "Unix error " + this.unixErrno +
      " during operation " + this.operation +
      " (" + strerror(this.unixErrno).readString() + ")";
  };

  /**
   * |true| if the error was raised because a file or directory
   * already exists, |false| otherwise.
   */
  Object.defineProperty(OSError.prototype, "becauseExists", {
    get: function becauseExists() {
      return this.unixErrno == OS.Constants.libc.EEXIST;
    }
  });
  /**
   * |true| if the error was raised because a file or directory
   * does not exist, |false| otherwise.
   */
  Object.defineProperty(OSError.prototype, "becauseNoSuchFile", {
    get: function becauseNoSuchFile() {
      return this.unixErrno == OS.Constants.libc.ENOENT;
    }
  });

  /**
   * |true| if the error was raised because a directory is not empty
   * does not exist, |false| otherwise.
   */
   Object.defineProperty(OSError.prototype, "becauseNotEmpty", {
     get: function becauseNotEmpty() {
       return this.unixErrno == OS.Constants.libc.ENOTEMPTY;
     }
   });
  /**
   * |true| if the error was raised because a file or directory
   * is closed, |false| otherwise.
   */
  Object.defineProperty(OSError.prototype, "becauseClosed", {
    get: function becauseClosed() {
      return this.unixErrno == OS.Constants.libc.EBADF;
    }
  });

  /**
   * Serialize an instance of OSError to something that can be
   * transmitted across threads (not necessarily a string).
   */
  OSError.toMsg = function toMsg(error) {
    return {
      operation: error.operation,
      unixErrno: error.unixErrno
    };
  };

  /**
   * Deserialize a message back to an instance of OSError
   */
  OSError.fromMsg = function fromMsg(msg) {
    return new OSError(msg.operation, msg.unixErrno);
  };

  exports.OS.Shared.Unix.Error = OSError;

  /**
   * Code shared by implementations of File.Info on Unix
   *
   * @constructor
  */
  let AbstractInfo = function AbstractInfo(isDir, isSymLink, size, lastAccessDate,
                                           lastModificationDate, unixLastStatusChangeDate,
                                           unixOwner, unixGroup, unixMode) {
    this._isDir = isDir;
    this._isSymlLink = isSymLink;
    this._size = size;
    this._lastAccessDate = lastAccessDate;
    this._lastModificationDate = lastModificationDate;
    this._unixLastStatusChangeDate = unixLastStatusChangeDate;
    this._unixOwner = unixOwner;
    this._unixGroup = unixGroup;
    this._unixMode = unixMode;
  };

  AbstractInfo.prototype = {
    /**
     * |true| if this file is a directory, |false| otherwise
     */
    get isDir() {
      return this._isDir;
    },
    /**
     * |true| if this file is a symbolink link, |false| otherwise
     */
    get isSymLink() {
      return this._isSymlLink;
    },
    /**
     * The size of the file, in bytes.
     *
     * Note that the result may be |NaN| if the size of the file cannot be
     * represented in JavaScript.
     *
     * @type {number}
     */
    get size() {
      return this._size;
    },
    /**
     * The date of last access to this file.
     *
     * Note that the definition of last access may depend on the
     * underlying operating system and file system.
     *
     * @type {Date}
     */
    get lastAccessDate() {
      return this._lastAccessDate;
    },
    /**
     * Return the date of last modification of this file.
     */
    get lastModificationDate() {
      return this._lastModificationDate;
    },
    /**
     * Return the date at which the status of this file was last modified
     * (this is the date of the latest write/renaming/mode change/...
     * of the file)
     */
    get unixLastStatusChangeDate() {
      return this._unixLastStatusChangeDate;
    },
    /*
     * Return the Unix owner of this file
     */
    get unixOwner() {
      return this._unixOwner;
    },
    /*
     * Return the Unix group of this file
     */
    get unixGroup() {
      return this._unixGroup;
    },
    /*
     * Return the Unix group of this file
     */
    get unixMode() {
      return this._unixMode;
    }
  };
  exports.OS.Shared.Unix.AbstractInfo = AbstractInfo;

  /**
   * Code shared by implementations of File.DirectoryIterator.Entry on Unix
   *
   * @constructor
  */
  let AbstractEntry = function AbstractEntry(isDir, isSymLink, name, path) {
    this._isDir = isDir;
    this._isSymlLink = isSymLink;
    this._name = name;
    this._path = path;
  };

  AbstractEntry.prototype = {
    /**
     * |true| if the entry is a directory, |false| otherwise
     */
    get isDir() {
      return this._isDir;
    },
    /**
     * |true| if the entry is a directory, |false| otherwise
     */
    get isSymLink() {
      return this._isSymlLink;
    },
    /**
     * The name of the entry
     * @type {string}
     */
    get name() {
      return this._name;
    },
    /**
     * The full path to the entry
     */
    get path() {
      return this._path;
    }
  };
  exports.OS.Shared.Unix.AbstractEntry = AbstractEntry;

  // Special constants that need to be defined on all platforms

   Object.defineProperty(exports.OS.Shared, "POS_START", { value: exports.OS.Constants.libc.SEEK_SET });
   Object.defineProperty(exports.OS.Shared, "POS_CURRENT", { value: exports.OS.Constants.libc.SEEK_CUR });
   Object.defineProperty(exports.OS.Shared, "POS_END", { value: exports.OS.Constants.libc.SEEK_END });

  // Special types that need to be defined for communication
  // between threads
  let Types = exports.OS.Shared.Type;

   /**
    * Native paths
    *
    * Under Unix, expressed as C strings
    */
  Types.path = Types.cstring.withName("[in] path");
  Types.out_path = Types.out_cstring.withName("[out] path");

  // Special constructors that need to be defined on all threads
  OSError.closed = function closed(operation) {
    return new OSError(operation, OS.Constants.libc.EBADF);
  };

  OSError.exists = function exists(operation) {
    return new OSError(operation, OS.Constants.libc.EEXIST);
  };

  OSError.noSuchFile = function noSuchFile(operation) {
    return new OSError(operation, OS.Constants.libc.ENOENT);
  };
})(this);