/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
/* 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"

native HKEY(HKEY);

/**
 * This interface is designed to provide scriptable access to the Windows
 * registry system ("With Great Power Comes Great Responsibility").  The
 * interface represents a single key in the registry.
 *
 * This interface is highly Win32 specific.
 */
[scriptable, uuid(2555b930-d64f-437e-9be7-0a2cb252c1f4)]
interface nsIWindowsRegKey : nsISupports
{
  /**
   * Root keys.  The values for these keys correspond to the values from
   * WinReg.h in the MS Platform SDK.  The ROOT_KEY_ prefix corresponds to the
   * HKEY_ prefix in the MS Platform SDK.
   *
   * This interface is not restricted to using only these root keys.
   */
  const unsigned long ROOT_KEY_CLASSES_ROOT     = 0x80000000;
  const unsigned long ROOT_KEY_CURRENT_USER     = 0x80000001;
  const unsigned long ROOT_KEY_LOCAL_MACHINE    = 0x80000002;

  /**
   * Values for the mode parameter passed to the open and create methods.
   * The values defined here correspond to the REGSAM values defined in
   * WinNT.h in the MS Platform SDK, where ACCESS_ is replaced with KEY_.
   *
   * This interface is not restricted to using only these access types.
   */
  const unsigned long ACCESS_BASIC              = 0x00020000;
  const unsigned long ACCESS_QUERY_VALUE        = 0x00000001;
  const unsigned long ACCESS_SET_VALUE          = 0x00000002;
  const unsigned long ACCESS_CREATE_SUB_KEY     = 0x00000004;
  const unsigned long ACCESS_ENUMERATE_SUB_KEYS = 0x00000008;
  const unsigned long ACCESS_NOTIFY             = 0x00000010;
  const unsigned long ACCESS_READ               = ACCESS_BASIC |
                                                  ACCESS_QUERY_VALUE |
                                                  ACCESS_ENUMERATE_SUB_KEYS |
                                                  ACCESS_NOTIFY;
  const unsigned long ACCESS_WRITE              = ACCESS_BASIC |
                                                  ACCESS_SET_VALUE |
                                                  ACCESS_CREATE_SUB_KEY;
  const unsigned long ACCESS_ALL                = ACCESS_READ |
                                                  ACCESS_WRITE;
  const unsigned long WOW64_32                  = 0x00000200;
  const unsigned long WOW64_64                  = 0x00000100;


  /**
   * Values for the type of a registry value.  The numeric values of these
   * constants are taken directly from WinNT.h in the MS Platform SDK.
   * The Microsoft documentation should be consulted for the exact meaning of
   * these value types.
   *
   * This interface is somewhat restricted to using only these value types.
   * There is no method that is directly equivalent to RegQueryValueEx or
   * RegSetValueEx.  In particular, this interface does not support the
   * REG_MULTI_SZ and REG_EXPAND_SZ value types.  It is still possible to
   * enumerate values that have other types (i.e., getValueType may return a
   * type not defined below).
   */
  const unsigned long TYPE_NONE   = 0;  // REG_NONE
  const unsigned long TYPE_STRING = 1;  // REG_SZ
  const unsigned long TYPE_BINARY = 3;  // REG_BINARY
  const unsigned long TYPE_INT    = 4;  // REG_DWORD
  const unsigned long TYPE_INT64  = 11; // REG_QWORD

  /**
   * This attribute exposes the native HKEY and is available to provide C++
   * consumers with the flexibility of making other Windows registry API calls
   * that are not exposed via this interface.
   * 
   * It is possible to initialize this object by setting an HKEY on it.  In
   * that case, it is the responsibility of the consumer setting the HKEY to
   * ensure that it is a valid HKEY.
   *
   * WARNING: Setting the key does not close the old key.
   */
  [noscript] attribute HKEY key;

  /**
   * This method closes the key.  If the key is already closed, then this
   * method does nothing.
   */
  void close();

  /**
   * This method opens an existing key.  This method fails if the key
   * does not exist.
   *
   * NOTE: On 32-bit Windows, it is valid to pass any HKEY as the rootKey
   * parameter of this function.  However, for compatibility with 64-bit
   * Windows, that usage should probably be avoided in favor of openChild.
   *
   * @param rootKey
   *        A root key defined above or any valid HKEY on 32-bit Windows.
   * @param relPath
   *        A relative path from the given root key.
   * @param mode
   *        Access mode, which is a bit-wise OR of the ACCESS_ values defined
   *        above.
   */
  void open(in unsigned long rootKey, in AString relPath, in unsigned long mode);

  /**
   * This method opens an existing key or creates a new key.
   *
   * NOTE: On 32-bit Windows, it is valid to pass any HKEY as the rootKey
   * parameter of this function.  However, for compatibility with 64-bit
   * Windows, that usage should probably be avoided in favor of createChild.
   *
   * @param rootKey
   *        A root key defined above or any valid HKEY on 32-bit Windows.
   * @param relPath
   *        A relative path from the given root key.
   * @param mode
   *        Access mode, which is a bit-wise OR of the ACCESS_ values defined
   *        above.
   */
  void create(in unsigned long rootKey, in AString relPath, in unsigned long mode);

  /**
   * This method opens a subkey relative to this key.  This method fails if the
   * key does not exist.
   *
   * @return nsIWindowsRegKey for the newly opened subkey.
   */
  nsIWindowsRegKey openChild(in AString relPath, in unsigned long mode);

  /**
   * This method opens or creates a subkey relative to this key.
   *
   * @return nsIWindowsRegKey for the newly opened or created subkey.
   */
  nsIWindowsRegKey createChild(in AString relPath, in unsigned long mode);

  /**
   * This attribute returns the number of child keys.
   */
  readonly attribute unsigned long childCount;

  /**
   * This method returns the name of the n'th child key.
   *
   * @param index
   *        The index of the requested child key.
   */
  AString getChildName(in unsigned long index);

  /**
   * This method checks to see if the key has a child by the given name.
   *
   * @param name
   *        The name of the requested child key.
   */
  boolean hasChild(in AString name);

  /**
   * This attribute returns the number of values under this key.
   */
  readonly attribute unsigned long valueCount;

  /**
   * This method returns the name of the n'th value under this key.
   *
   * @param index
   *        The index of the requested value.
   */
  AString getValueName(in unsigned long index);

  /**
   * This method checks to see if the key has a value by the given name.
   *
   * @param name
   *        The name of the requested value.
   */
  boolean hasValue(in AString name);

  /**
   * This method removes a child key and all of its values.  This method will
   * fail if the key has any children of its own. 
   *
   * @param relPath
   *        The relative path from this key to the key to be removed.
   */
  void removeChild(in AString relPath);

  /**
   * This method removes the value with the given name.
   *
   * @param name
   *        The name of the value to be removed.
   */
  void removeValue(in AString name);

  /**
   * This method returns the type of the value with the given name.  The return
   * value is one of the "TYPE_" constants defined above.
   *
   * @param name
   *        The name of the value to query.
   */
  unsigned long getValueType(in AString name);

  /**
   * This method reads the string contents of the named value as a Unicode
   * string.
   *
   * @param name
   *        The name of the value to query.  This parameter can be the empty
   *        string to request the key's default value.
   */
  AString readStringValue(in AString name);

  /**
   * This method reads the integer contents of the named value.
   *
   * @param name
   *        The name of the value to query.
   */
  unsigned long readIntValue(in AString name);

  /**
   * This method reads the 64-bit integer contents of the named value.
   *
   * @param name
   *        The name of the value to query.
   */
  unsigned long long readInt64Value(in AString name);

  /**
   * This method reads the binary contents of the named value under this key.
   *
   * JavaScript callers should take care with the result of this method since
   * it will be byte-expanded to form a JS string.  (The binary data will be
   * treated as an ISO-Latin-1 character string, which it is not).
   *
   * @param name
   *        The name of the value to query.
   */
  ACString readBinaryValue(in AString name);

  /**
   * This method writes the unicode string contents of the named value.  The
   * value will be created if it does not already exist.
   *
   * @param name
   *        The name of the value to modify.  This parameter can be the empty
   *        string to modify the key's default value.
   * @param data
   *        The data for the value to modify.
   */
  void writeStringValue(in AString name, in AString data);

  /**
   * This method writes the integer contents of the named value.  The value
   * will be created if it does not already exist.
   *
   * @param name
   *        The name of the value to modify.
   * @param data
   *        The data for the value to modify.
   */
  void writeIntValue(in AString name, in unsigned long data);

  /**
   * This method writes the 64-bit integer contents of the named value.  The
   * value will be created if it does not already exist.
   *
   * @param name
   *        The name of the value to modify.
   * @param data
   *        The data for the value to modify.
   */
  void writeInt64Value(in AString name, in unsigned long long data);

  /**
   * This method writes the binary contents of the named value.  The value will
   * be created if it does not already exist.
   * 
   * JavaScript callers should take care with the value passed to this method
   * since it will be truncated from a JS string (unicode) to a ISO-Latin-1
   * string.  (The binary data will be treated as an ISO-Latin-1 character
   * string, which it is not).  So, JavaScript callers should only pass
   * character values in the range \u0000 to \u00FF, or else data loss will
   * occur.
   *
   * @param name
   *        The name of the value to modify.
   * @param data
   *        The data for the value to modify.
   */
  void writeBinaryValue(in AString name, in ACString data);

  /**
   * This method starts watching the key to see if any of its values have
   * changed.  The key must have been opened with mode including ACCESS_NOTIFY.
   * If recurse is true, then this key and any of its descendant keys are
   * watched.  Otherwise, only this key is watched.
   *
   * @param recurse
   *        Indicates whether or not to also watch child keys.
   */
  void startWatching(in boolean recurse);

  /**
   * This method stops any watching of the key initiated by a call to
   * startWatching.  This method does nothing if the key is not being watched.
   */
  void stopWatching();

  /**
   * This method returns true if the key is being watched for changes (i.e.,
   * if startWatching() was called).
   */
  boolean isWatching();

  /**
   * This method returns true if the key has changed and false otherwise.
   * This method will always return false if startWatching was not called.
   */
  boolean hasChanged();
};