/* * Copyright (c) 2008-2013 Apple Inc. All rights reserved. * * @APPLE_APACHE_LICENSE_HEADER_START@ * * Licensed under the Apache License, Version 2.0 (the "License"); * you may not use this file except in compliance with the License. * You may obtain a copy of the License at * * http://www.apache.org/licenses/LICENSE-2.0 * * Unless required by applicable law or agreed to in writing, software * distributed under the License is distributed on an "AS IS" BASIS, * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. * See the License for the specific language governing permissions and * limitations under the License. * * @APPLE_APACHE_LICENSE_HEADER_END@ */ /* * IMPORTANT: This header file describes INTERNAL interfaces to libdispatch * which are subject to change in future releases of Mac OS X. Any applications * relying on these interfaces WILL break. */ #ifndef __DISPATCH_QUEUE_PRIVATE__ #define __DISPATCH_QUEUE_PRIVATE__ #ifndef __DISPATCH_INDIRECT__ #error "Please #include <dispatch/private.h> instead of this file directly." #include <dispatch/base.h> // for HeaderDoc #endif __BEGIN_DECLS /*! * @enum dispatch_queue_flags_t * * @constant DISPATCH_QUEUE_OVERCOMMIT * The queue will create a new thread for invoking blocks, regardless of how * busy the computer is. */ enum { DISPATCH_QUEUE_OVERCOMMIT = 0x2ull, }; #define DISPATCH_QUEUE_FLAGS_MASK (DISPATCH_QUEUE_OVERCOMMIT) /*! * @function dispatch_queue_attr_make_with_overcommit * * @discussion * Returns a dispatch queue attribute value with the overcommit flag set to the * specified value. * * @param attr * A queue attribute value to be combined with the overcommit flag, or NULL. * * @param overcommit * Boolean overcommit flag. * * @return * Returns an attribute value which may be provided to dispatch_queue_create(). * This new value combines the attributes specified by the 'attr' parameter and * the overcommit flag. */ __OSX_AVAILABLE_STARTING(__MAC_10_10, __IPHONE_8_0) DISPATCH_EXPORT DISPATCH_WARN_RESULT DISPATCH_PURE DISPATCH_NOTHROW dispatch_queue_attr_t dispatch_queue_attr_make_with_overcommit(dispatch_queue_attr_t attr, bool overcommit); /*! * @typedef dispatch_queue_priority_t * * @constant DISPATCH_QUEUE_PRIORITY_NON_INTERACTIVE * Items dispatched to the queue will run at non-interactive priority. * This priority level is intended for user-initiated application activity that * is long-running and CPU or IO intensive and that the user is actively waiting * on, but that should not interfere with interactive use of the application. * * This global queue priority level is mapped to QOS_CLASS_UTILITY. */ #define DISPATCH_QUEUE_PRIORITY_NON_INTERACTIVE INT8_MIN /*! * @function dispatch_queue_set_width * * @abstract * Set the width of concurrency for a given queue. The width of a serial queue * is one. * * @discussion * This SPI is DEPRECATED and will be removed in a future release. * Uses of this SPI to make a queue concurrent by setting its width to LONG_MAX * should be replaced by passing DISPATCH_QUEUE_CONCURRENT to * dispatch_queue_create(). * Uses of this SPI to limit queue concurrency are not recommended and should * be replaced by alternative mechanisms such as a dispatch semaphore created * with the desired concurrency width. * * @param queue * The queue to adjust. Passing the main queue or a global concurrent queue * will be ignored. * * @param width * The new maximum width of concurrency depending on available resources. * If zero is passed, then the value is promoted to one. * Negative values are magic values that map to automatic width values. * Unknown negative values default to DISPATCH_QUEUE_WIDTH_MAX_LOGICAL_CPUS. */ #define DISPATCH_QUEUE_WIDTH_ACTIVE_CPUS -1 #define DISPATCH_QUEUE_WIDTH_MAX_PHYSICAL_CPUS -2 #define DISPATCH_QUEUE_WIDTH_MAX_LOGICAL_CPUS -3 __OSX_AVAILABLE_BUT_DEPRECATED_MSG(__MAC_10_6,__MAC_10_10,__IPHONE_4_0,__IPHONE_8_0, \ "Use dispatch_queue_create(name, DISPATCH_QUEUE_CONCURRENT) instead") DISPATCH_EXPORT DISPATCH_NONNULL_ALL DISPATCH_NOTHROW void dispatch_queue_set_width(dispatch_queue_t dq, long width); /*! * @function dispatch_queue_create_with_target * * @abstract * Creates a new dispatch queue with a specified target queue. * * @discussion * Dispatch queues created with the DISPATCH_QUEUE_SERIAL or a NULL attribute * invoke blocks serially in FIFO order. * * Dispatch queues created with the DISPATCH_QUEUE_CONCURRENT attribute may * invoke blocks concurrently (similarly to the global concurrent queues, but * potentially with more overhead), and support barrier blocks submitted with * the dispatch barrier API, which e.g. enables the implementation of efficient * reader-writer schemes. * * When a dispatch queue is no longer needed, it should be released with * dispatch_release(). Note that any pending blocks submitted to a queue will * hold a reference to that queue. Therefore a queue will not be deallocated * until all pending blocks have finished. * * @param label * A string label to attach to the queue. * This parameter is optional and may be NULL. * * @param attr * DISPATCH_QUEUE_SERIAL, DISPATCH_QUEUE_CONCURRENT, or the result of a call to * the function dispatch_queue_attr_make_with_qos_class(). * * @param target * The target queue for the newly created queue. The target queue is retained. * If this parameter is DISPATCH_TARGET_QUEUE_DEFAULT, sets the queue's target * queue to the default target queue for the given queue type. * * @result * The newly created dispatch queue. */ __OSX_AVAILABLE_STARTING(__MAC_10_9,__IPHONE_7_0) DISPATCH_EXPORT DISPATCH_MALLOC DISPATCH_RETURNS_RETAINED DISPATCH_WARN_RESULT DISPATCH_NOTHROW dispatch_queue_t dispatch_queue_create_with_target(const char *label, dispatch_queue_attr_t attr, dispatch_queue_t target); #ifdef __BLOCKS__ /*! * @function dispatch_pthread_root_queue_create * * @abstract * Creates a new concurrent dispatch root queue with a pthread-based pool of * worker threads owned by the application. * * @discussion * Dispatch pthread root queues are similar to the global concurrent dispatch * queues in that they invoke blocks concurrently, however the blocks are not * executed on ordinary worker threads but use a dedicated pool of pthreads not * shared with the global queues or any other pthread root queues. * * NOTE: this is a special-purpose facility that should only be used in very * limited circumstances, in almost all cases the global concurrent queues * should be preferred. While this facility allows for more flexibility in * configuring worker threads for special needs it comes at the cost of * increased overall memory usage due to reduced thread sharing and higher * latency in worker thread bringup. * * Dispatch pthread root queues do not support suspension, application context * and change of width or of target queue. They can however be used as the * target queue for serial or concurrent queues obtained via * dispatch_queue_create() or dispatch_queue_create_with_target(), which * enables the blocks submitted to those queues to be processed on the root * queue's pthread pool. * * When a dispatch pthread root queue is no longer needed, it should be * released with dispatch_release(). Existing worker pthreads and pending blocks * submitted to the root queue will hold a reference to the queue so it will not * be deallocated until all blocks have finished and worker threads exited. * * @param label * A string label to attach to the queue. * This parameter is optional and may be NULL. * * @param flags * Pass flags value returned by dispatch_pthread_root_queue_flags_pool_size() * or 0 if unused. * * @param attr * Attributes passed to pthread_create(3) when creating worker pthreads. This * parameter is copied and can be destroyed after this call returns. * This parameter is optional and may be NULL. * * @param configure * Configuration block called on newly created worker pthreads before any blocks * for the root queue are executed. The block may configure the current thread * as needed. * This parameter is optional and may be NULL. * * @result * The newly created dispatch pthread root queue. */ __OSX_AVAILABLE_STARTING(__MAC_10_9,__IPHONE_6_0) DISPATCH_EXPORT DISPATCH_MALLOC DISPATCH_RETURNS_RETAINED DISPATCH_WARN_RESULT DISPATCH_NOTHROW dispatch_queue_t dispatch_pthread_root_queue_create(const char *label, unsigned long flags, const pthread_attr_t *attr, dispatch_block_t configure); /*! * @function dispatch_pthread_root_queue_flags_pool_size * * @abstract * Returns flags argument to pass to dispatch_pthread_root_queue_create() to * specify the maximum size of the pthread pool to use for a pthread root queue. * * @param pool_size * Maximum size of the pthread pool to use for the root queue. The number of * pthreads created for this root queue will never exceed this number but there * is no guarantee that the specified number will be reached. * Pass 0 to specify that a default pool size determined by the system should * be used. * NOTE: passing pool_size == 1 does NOT make the pthread root queue equivalent * to a serial queue. * * @result * The flags argument to pass to dispatch_pthread_root_queue_create(). */ DISPATCH_INLINE DISPATCH_ALWAYS_INLINE unsigned long dispatch_pthread_root_queue_flags_pool_size(uint8_t pool_size) { #define _DISPATCH_PTHREAD_ROOT_QUEUE_FLAG_POOL_SIZE (0x80000000ul) return (_DISPATCH_PTHREAD_ROOT_QUEUE_FLAG_POOL_SIZE | (unsigned long)pool_size); } #endif /* __BLOCKS__ */ /*! * @constant DISPATCH_APPLY_CURRENT_ROOT_QUEUE * @discussion Constant to pass to the dispatch_apply() and dispatch_apply_f() * functions to indicate that the root queue for the current thread should be * used (i.e. one of the global concurrent queues or a queue created with * dispatch_pthread_root_queue_create()). If there is no such queue, the * default priority global concurrent queue will be used. */ #define DISPATCH_APPLY_CURRENT_ROOT_QUEUE NULL /*! * @function dispatch_assert_queue * * @abstract * Verifies that the current block is executing on a certain dispatch queue. * * @discussion * Some code expects to be run on a specific dispatch queue. This function * verifies that expectation for debugging. * * This function will only return if the currently executing block was submitted * to the specified queue or to any queue targeting it (see * dispatch_set_target_queue()). Otherwise, it logs an explanation to the system * log, then terminates the application. * * When dispatch_assert_queue() is called outside of the context of a * submitted block, its behavior is undefined. * * Passing the result of dispatch_get_main_queue() to this function verifies * that the current block was submitted to the main queue or to a queue * targeting it. * IMPORTANT: this is NOT the same as verifying that the current block is * executing on the main thread. * * The variant dispatch_assert_queue_debug() is compiled out when the * preprocessor macro NDEBUG is defined. (See also assert(3)). * * @param queue * The dispatch queue that the current block is expected to run on. * The result of passing NULL in this parameter is undefined. */ __OSX_AVAILABLE_STARTING(__MAC_10_9,__IPHONE_7_0) DISPATCH_EXPORT DISPATCH_NONNULL1 void dispatch_assert_queue(dispatch_queue_t queue); /*! * @function dispatch_assert_queue_not * * @abstract * Verifies that the current block is not executing on a certain dispatch queue. * * @discussion * This function is the equivalent of dispatch_queue_assert() with the test for * equality inverted. See discussion there. * * The variant dispatch_assert_queue_not_debug() is compiled out when the * preprocessor macro NDEBUG is defined. (See also assert(3)). * * @param queue * The dispatch queue that the current block is expected not to run on. * The result of passing NULL in this parameter is undefined. */ __OSX_AVAILABLE_STARTING(__MAC_10_9,__IPHONE_7_0) DISPATCH_EXPORT DISPATCH_NONNULL1 void dispatch_assert_queue_not(dispatch_queue_t queue); #ifdef NDEBUG #define dispatch_assert_queue_debug(q) ((void)0) #define dispatch_assert_queue_not_debug(q) ((void)0) #else #define dispatch_assert_queue_debug(q) dispatch_assert_queue(q) #define dispatch_assert_queue_not_debug(q) dispatch_assert_queue_not(q) #endif /*! * @function dispatch_async_enforce_qos_class_f * * @abstract * Submits a function for asynchronous execution on a dispatch queue. * * @discussion * See dispatch_async() for details. The QOS will be enforced as if * this was called: * <code> * dispatch_async(queue, dispatch_block_create(DISPATCH_BLOCK_ENFORCE_QOS_CLASS, ^{ * work(context); * }); * </code> * * @param queue * The target dispatch queue to which the function is submitted. * The system will hold a reference on the target queue until the function * has returned. * The result of passing NULL in this parameter is undefined. * * @param context * The application-defined context parameter to pass to the function. * * @param work * The application-defined function to invoke on the target queue. The first * parameter passed to this function is the context provided to * dispatch_async_f(). * The result of passing NULL in this parameter is undefined. */ __OSX_AVAILABLE_STARTING(__MAC_10_11,__IPHONE_9_0) DISPATCH_EXPORT DISPATCH_NONNULL1 DISPATCH_NONNULL3 DISPATCH_NOTHROW void dispatch_async_enforce_qos_class_f(dispatch_queue_t queue, void *context, dispatch_function_t work); __END_DECLS #endif