/* * Copyright (c) 2009-2013 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_IO_PRIVATE__ #define __DISPATCH_IO_PRIVATE__ #ifndef __DISPATCH_INDIRECT__ #error "Please #include <dispatch/dispatch.h> instead of this file directly." #include <dispatch/base.h> // for HeaderDoc #endif __BEGIN_DECLS /*! * @function dispatch_read_f * Schedule a read operation for asynchronous execution on the specified file * descriptor. The specified handler is enqueued with the data read from the * file descriptor when the operation has completed or an error occurs. * * The data object passed to the handler will be automatically released by the * system when the handler returns. It is the responsibility of the application * to retain, concatenate or copy the data object if it is needed after the * handler returns. * * The data object passed to the handler will only contain as much data as is * currently available from the file descriptor (up to the specified length). * * If an unrecoverable error occurs on the file descriptor, the handler will be * enqueued with the appropriate error code along with a data object of any data * that could be read successfully. * * An invocation of the handler with an error code of zero and an empty data * object indicates that EOF was reached. * * The system takes control of the file descriptor until the handler is * enqueued, and during this time file descriptor flags such as O_NONBLOCK will * be modified by the system on behalf of the application. It is an error for * the application to modify a file descriptor directly while it is under the * control of the system, but it may create additional dispatch I/O convenience * operations or dispatch I/O channels associated with that file descriptor. * * @param fd The file descriptor from which to read the data. * @param length The length of data to read from the file descriptor, * or SIZE_MAX to indicate that all of the data currently * available from the file descriptor should be read. * @param queue The dispatch queue to which the handler should be * submitted. * @param context The application-defined context parameter to pass to * the handler function. * @param handler The handler to enqueue when data is ready to be * delivered. * @param context Application-defined context parameter. * @param data The data read from the file descriptor. * @param error An errno condition for the read operation or * zero if the read was successful. */ __OSX_AVAILABLE_STARTING(__MAC_10_9,__IPHONE_7_0) DISPATCH_EXPORT DISPATCH_NONNULL3 DISPATCH_NONNULL5 DISPATCH_NOTHROW void dispatch_read_f(dispatch_fd_t fd, size_t length, dispatch_queue_t queue, void *context, void (*handler)(void *context, dispatch_data_t data, int error)); /*! * @function dispatch_write_f * Schedule a write operation for asynchronous execution on the specified file * descriptor. The specified handler is enqueued when the operation has * completed or an error occurs. * * If an unrecoverable error occurs on the file descriptor, the handler will be * enqueued with the appropriate error code along with the data that could not * be successfully written. * * An invocation of the handler with an error code of zero indicates that the * data was fully written to the channel. * * The system takes control of the file descriptor until the handler is * enqueued, and during this time file descriptor flags such as O_NONBLOCK will * be modified by the system on behalf of the application. It is an error for * the application to modify a file descriptor directly while it is under the * control of the system, but it may create additional dispatch I/O convenience * operations or dispatch I/O channels associated with that file descriptor. * * @param fd The file descriptor to which to write the data. * @param data The data object to write to the file descriptor. * @param queue The dispatch queue to which the handler should be * submitted. * @param context The application-defined context parameter to pass to * the handler function. * @param handler The handler to enqueue when the data has been written. * @param context Application-defined context parameter. * @param data The data that could not be written to the I/O * channel, or NULL. * @param error An errno condition for the write operation or * zero if the write was successful. */ __OSX_AVAILABLE_STARTING(__MAC_10_9,__IPHONE_7_0) DISPATCH_EXPORT DISPATCH_NONNULL2 DISPATCH_NONNULL3 DISPATCH_NONNULL5 DISPATCH_NOTHROW void dispatch_write_f(dispatch_fd_t fd, dispatch_data_t data, dispatch_queue_t queue, void *context, void (*handler)(void *context, dispatch_data_t data, int error)); /*! * @function dispatch_io_create_f * Create a dispatch I/O channel associated with a file descriptor. The system * takes control of the file descriptor until the channel is closed, an error * occurs on the file descriptor or all references to the channel are released. * At that time the specified cleanup handler will be enqueued and control over * the file descriptor relinquished. * * While a file descriptor is under the control of a dispatch I/O channel, file * descriptor flags such as O_NONBLOCK will be modified by the system on behalf * of the application. It is an error for the application to modify a file * descriptor directly while it is under the control of a dispatch I/O channel, * but it may create additional channels associated with that file descriptor. * * @param type The desired type of I/O channel (DISPATCH_IO_STREAM * or DISPATCH_IO_RANDOM). * @param fd The file descriptor to associate with the I/O channel. * @param queue The dispatch queue to which the handler should be submitted. * @param context The application-defined context parameter to pass to * the cleanup handler function. * @param cleanup_handler The handler to enqueue when the system * relinquishes control over the file descriptor. * @param context Application-defined context parameter. * @param error An errno condition if control is relinquished * because channel creation failed, zero otherwise. * @result The newly created dispatch I/O channel or NULL if an error * occurred (invalid type specified). */ __OSX_AVAILABLE_STARTING(__MAC_10_9,__IPHONE_7_0) DISPATCH_EXPORT DISPATCH_MALLOC DISPATCH_RETURNS_RETAINED DISPATCH_WARN_RESULT DISPATCH_NOTHROW dispatch_io_t dispatch_io_create_f(dispatch_io_type_t type, dispatch_fd_t fd, dispatch_queue_t queue, void *context, void (*cleanup_handler)(void *context, int error)); /*! * @function dispatch_io_create_with_path_f * Create a dispatch I/O channel associated with a path name. The specified * path, oflag and mode parameters will be passed to open(2) when the first I/O * operation on the channel is ready to execute and the resulting file * descriptor will remain open and under the control of the system until the * channel is closed, an error occurs on the file descriptor or all references * to the channel are released. At that time the file descriptor will be closed * and the specified cleanup handler will be enqueued. * * @param type The desired type of I/O channel (DISPATCH_IO_STREAM * or DISPATCH_IO_RANDOM). * @param path The absolute path to associate with the I/O channel. * @param oflag The flags to pass to open(2) when opening the file at * path. * @param mode The mode to pass to open(2) when creating the file at * path (i.e. with flag O_CREAT), zero otherwise. * @param queue The dispatch queue to which the handler should be * submitted. * @param context The application-defined context parameter to pass to * the cleanup handler function. * @param cleanup_handler The handler to enqueue when the system * has closed the file at path. * @param context Application-defined context parameter. * @param error An errno condition if control is relinquished * because channel creation or opening of the * specified file failed, zero otherwise. * @result The newly created dispatch I/O channel or NULL if an error * occurred (invalid type or non-absolute path specified). */ __OSX_AVAILABLE_STARTING(__MAC_10_9,__IPHONE_7_0) DISPATCH_EXPORT DISPATCH_NONNULL2 DISPATCH_MALLOC DISPATCH_RETURNS_RETAINED DISPATCH_WARN_RESULT DISPATCH_NOTHROW dispatch_io_t dispatch_io_create_with_path_f(dispatch_io_type_t type, const char *path, int oflag, mode_t mode, dispatch_queue_t queue, void *context, void (*cleanup_handler)(void *context, int error)); /*! * @function dispatch_io_create_with_io_f * Create a new dispatch I/O channel from an existing dispatch I/O channel. * The new channel inherits the file descriptor or path name associated with * the existing channel, but not its channel type or policies. * * If the existing channel is associated with a file descriptor, control by the * system over that file descriptor is extended until the new channel is also * closed, an error occurs on the file descriptor, or all references to both * channels are released. At that time the specified cleanup handler will be * enqueued and control over the file descriptor relinquished. * * While a file descriptor is under the control of a dispatch I/O channel, file * descriptor flags such as O_NONBLOCK will be modified by the system on behalf * of the application. It is an error for the application to modify a file * descriptor directly while it is under the control of a dispatch I/O channel, * but it may create additional channels associated with that file descriptor. * * @param type The desired type of I/O channel (DISPATCH_IO_STREAM * or DISPATCH_IO_RANDOM). * @param io The existing channel to create the new I/O channel from. * @param queue The dispatch queue to which the handler should be submitted. * @param context The application-defined context parameter to pass to * the cleanup handler function. * @param cleanup_handler The handler to enqueue when the system * relinquishes control over the file descriptor * (resp. closes the file at path) associated with * the existing channel. * @param context Application-defined context parameter. * @param error An errno condition if control is relinquished * because channel creation failed, zero otherwise. * @result The newly created dispatch I/O channel or NULL if an error * occurred (invalid type specified). */ __OSX_AVAILABLE_STARTING(__MAC_10_9,__IPHONE_7_0) DISPATCH_EXPORT DISPATCH_NONNULL2 DISPATCH_MALLOC DISPATCH_RETURNS_RETAINED DISPATCH_WARN_RESULT DISPATCH_NOTHROW dispatch_io_t dispatch_io_create_with_io_f(dispatch_io_type_t type, dispatch_io_t io, dispatch_queue_t queue, void *context, void (*cleanup_handler)(void *context, int error)); /*! * @typedef dispatch_io_handler_function_t * The prototype of I/O handler functions for dispatch I/O operations. * * @param context Application-defined context parameter. * @param done A flag indicating whether the operation is complete. * @param data The data object to be handled. * @param error An errno condition for the operation. */ typedef void (*dispatch_io_handler_function_t)(void *context, bool done, dispatch_data_t data, int error); /*! * @function dispatch_io_read_f * Schedule a read operation for asynchronous execution on the specified I/O * channel. The I/O handler is enqueued one or more times depending on the * general load of the system and the policy specified on the I/O channel. * * Any data read from the channel is described by the dispatch data object * passed to the I/O handler. This object will be automatically released by the * system when the I/O handler returns. It is the responsibility of the * application to retain, concatenate or copy the data object if it is needed * after the I/O handler returns. * * Dispatch I/O handlers are not reentrant. The system will ensure that no new * I/O handler instance is invoked until the previously enqueued handler * function has returned. * * An invocation of the I/O handler with the done flag set indicates that the * read operation is complete and that the handler will not be enqueued again. * * If an unrecoverable error occurs on the I/O channel's underlying file * descriptor, the I/O handler will be enqueued with the done flag set, the * appropriate error code and a NULL data object. * * An invocation of the I/O handler with the done flag set, an error code of * zero and an empty data object indicates that EOF was reached. * * @param channel The dispatch I/O channel from which to read the data. * @param offset The offset relative to the channel position from which * to start reading (only for DISPATCH_IO_RANDOM). * @param length The length of data to read from the I/O channel, or * SIZE_MAX to indicate that data should be read until EOF * is reached. * @param queue The dispatch queue to which the I/O handler should be * submitted. * @param context The application-defined context parameter to pass to * the handler function. * @param io_handler The I/O handler to enqueue when data is ready to be * delivered. * @param context Application-defined context parameter. * @param done A flag indicating whether the operation is complete. * @param data An object with the data most recently read from the * I/O channel as part of this read operation, or NULL. * @param error An errno condition for the read operation or zero if * the read was successful. */ __OSX_AVAILABLE_STARTING(__MAC_10_9,__IPHONE_7_0) DISPATCH_EXPORT DISPATCH_NONNULL1 DISPATCH_NONNULL4 DISPATCH_NONNULL6 DISPATCH_NOTHROW void dispatch_io_read_f(dispatch_io_t channel, off_t offset, size_t length, dispatch_queue_t queue, void *context, dispatch_io_handler_function_t io_handler); /*! * @function dispatch_io_write_f * Schedule a write operation for asynchronous execution on the specified I/O * channel. The I/O handler is enqueued one or more times depending on the * general load of the system and the policy specified on the I/O channel. * * Any data remaining to be written to the I/O channel is described by the * dispatch data object passed to the I/O handler. This object will be * automatically released by the system when the I/O handler returns. It is the * responsibility of the application to retain, concatenate or copy the data * object if it is needed after the I/O handler returns. * * Dispatch I/O handlers are not reentrant. The system will ensure that no new * I/O handler instance is invoked until the previously enqueued handler * function has returned. * * An invocation of the I/O handler with the done flag set indicates that the * write operation is complete and that the handler will not be enqueued again. * * If an unrecoverable error occurs on the I/O channel's underlying file * descriptor, the I/O handler will be enqueued with the done flag set, the * appropriate error code and an object containing the data that could not be * written. * * An invocation of the I/O handler with the done flag set and an error code of * zero indicates that the data was fully written to the channel. * * @param channel The dispatch I/O channel on which to write the data. * @param offset The offset relative to the channel position from which * to start writing (only for DISPATCH_IO_RANDOM). * @param data The data to write to the I/O channel. The data object * will be retained by the system until the write operation * is complete. * @param queue The dispatch queue to which the I/O handler should be * submitted. * @param context The application-defined context parameter to pass to * the handler function. * @param io_handler The I/O handler to enqueue when data has been delivered. * @param context Application-defined context parameter. * @param done A flag indicating whether the operation is complete. * @param data An object of the data remaining to be * written to the I/O channel as part of this write * operation, or NULL. * @param error An errno condition for the write operation or zero * if the write was successful. */ __OSX_AVAILABLE_STARTING(__MAC_10_9,__IPHONE_7_0) DISPATCH_EXPORT DISPATCH_NONNULL1 DISPATCH_NONNULL3 DISPATCH_NONNULL4 DISPATCH_NONNULL6 DISPATCH_NOTHROW void dispatch_io_write_f(dispatch_io_t channel, off_t offset, dispatch_data_t data, dispatch_queue_t queue, void *context, dispatch_io_handler_function_t io_handler); /*! * @function dispatch_io_barrier_f * Schedule a barrier operation on the specified I/O channel; all previously * scheduled operations on the channel will complete before the provided * barrier function is enqueued onto the global queue determined by the * channel's target queue, and no subsequently scheduled operations will start * until the barrier function has returned. * * If multiple channels are associated with the same file descriptor, a barrier * operation scheduled on any of these channels will act as a barrier across all * channels in question, i.e. all previously scheduled operations on any of the * channels will complete before the barrier function is enqueued, and no * operations subsequently scheduled on any of the channels will start until the * barrier function has returned. * * While the barrier function is running, it may safely operate on the channel's * underlying file descriptor with fsync(2), lseek(2) etc. (but not close(2)). * * @param channel The dispatch I/O channel to schedule the barrier on. * @param context The application-defined context parameter to pass to * the barrier function. * @param barrier The barrier function. */ __OSX_AVAILABLE_STARTING(__MAC_10_9,__IPHONE_7_0) DISPATCH_EXPORT DISPATCH_NONNULL1 DISPATCH_NONNULL3 DISPATCH_NOTHROW void dispatch_io_barrier_f(dispatch_io_t channel, void *context, dispatch_function_t barrier); __END_DECLS #endif /* __DISPATCH_IO_PRIVATE__ */