xpcom/threads/nsIThreadPool.idl

   1 /* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
   2 /* vim:set ts=2 sw=2 sts=2 et cindent: */
   3 /* This Source Code Form is subject to the terms of the Mozilla Public
   4  * License, v. 2.0. If a copy of the MPL was not distributed with this
   5  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
   6
   7 #include "nsIEventTarget.idl"
   8
   9 [uuid(ef194cab-3f86-4b61-b132-e5e96a79e5d1)]
  10 interface nsIThreadPoolListener : nsISupports
  11 {
  12   /**
  13    * Called when a new thread is created by the thread pool. The notification
  14    * happens on the newly-created thread.
  15    */
  16   void onThreadCreated();
  17
  18   /**
  19    * Called when a thread is about to be destroyed by the thread pool. The
  20    * notification happens on the thread that is about to be destroyed.
  21    */
  22   void onThreadShuttingDown();
  23 };
  24
  25 /**
  26  * An interface to a thread pool.  A thread pool creates a limited number of
  27  * anonymous (unnamed) worker threads.  An event dispatched to the thread pool
  28  * will be run on the next available worker thread.
  29  */
  30 [uuid(76ce99c9-8e43-489a-9789-f27cc4424965)]
  31 interface nsIThreadPool : nsIEventTarget
  32 {
  33   /**
  34    * Shutdown the thread pool.  This method may not be executed from any thread
  35    * in the thread pool.  Instead, it is meant to be executed from another
  36    * thread (usually the thread that created this thread pool).  When this
  37    * function returns, the thread pool and all of its threads will be shutdown,
  38    * and it will no longer be possible to dispatch tasks to the thread pool.
  39    *
  40    * As a side effect, events on the current thread will be processed.
  41    */
  42   void shutdown();
  43
  44   /**
  45    * Shutdown the thread pool, but only wait for aTimeoutMs. After the timeout
  46    * expires, any threads that have not shutdown yet are leaked and will not
  47    * block shutdown.
  48    *
  49    * This method should only be used at during shutdown to cleanup threads that
  50    * made blocking calls to code outside our control, and can't be safely
  51    * terminated. We choose to leak them intentionally to avoid a shutdown hang.
  52    */
  53   [noscript] void shutdownWithTimeout(in long aTimeoutMs);
  54
  55   /**
  56    * Get/set the maximum number of threads allowed at one time in this pool.
  57    */
  58   attribute unsigned long threadLimit;
  59
  60   /**
  61    * Get/set the maximum number of idle threads kept alive.
  62    */
  63   attribute unsigned long idleThreadLimit;
  64
  65   /**
  66    * Get/set the amount of time in milliseconds before an idle thread is
  67    * destroyed.
  68    */
  69   attribute unsigned long idleThreadTimeout;
  70
  71   /**
  72    * If set to true the idle timeout will be calculated as idleThreadTimeout
  73    * divideded by the number of idle threads at the moment.  This may help
  74    * save memory allocations but still keep reasonable amount of idle threads.
  75    * Default is false, use |idleThreadTimeout| for all threads.
  76    */
  77   attribute boolean idleThreadTimeoutRegressive;
  78
  79   /**
  80    * Get/set the number of bytes reserved for the stack of all threads in
  81    * the pool. By default this is nsIThreadManager::DEFAULT_STACK_SIZE.
  82    */
  83   attribute unsigned long threadStackSize;
  84
  85   /**
  86    * An optional listener that will be notified when a thread is created or
  87    * destroyed in the course of the thread pool's operation.
  88    *
  89    * A listener will only receive notifications about threads created after the
  90    * listener is set so it is recommended that the consumer set the listener
  91    * before dispatching the first event. A listener that receives an
  92    * onThreadCreated() notification is guaranteed to always receive the
  93    * corresponding onThreadShuttingDown() notification.
  94    *
  95    * The thread pool takes ownership of the listener and releases it when the
  96    * shutdown() method is called. Threads created after the listener is set will
  97    * also take ownership of the listener so that the listener will be kept alive
  98    * long enough to receive the guaranteed onThreadShuttingDown() notification.
  99    */
 100   attribute nsIThreadPoolListener listener;
 101
 102   /**
 103    * Set the label for threads in the pool. All threads will be named
 104    * "<aName> #<n>", where <n> is a serial number.
 105    */
 106   void setName(in ACString aName);
 107 };