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/* $Id$
*/
/*
* Copyright (C) 2008-2011 Teluu Inc. (http://www.teluu.com)
* Copyright (C) 2003-2008 Benny Prijono <benny@prijono.org>
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
*/
#ifndef __PJ_IOQUEUE_H__
#define __PJ_IOQUEUE_H__
/**
* @file ioqueue.h
* @brief I/O Dispatching Mechanism
*/
#include <pj/types.h>
PJ_BEGIN_DECL
/**
* @defgroup PJ_IO Input/Output
* @brief Input/Output
* @ingroup PJ_OS
*
* This section contains API building blocks to perform network I/O and
* communications. If provides:
* - @ref PJ_SOCK
*\n
* A highly portable socket abstraction, runs on all kind of
* network APIs such as standard BSD socket, Windows socket, Linux
* \b kernel socket, PalmOS networking API, etc.
*
* - @ref pj_addr_resolve
*\n
* Portable address resolution, which implements #pj_gethostbyname().
*
* - @ref PJ_SOCK_SELECT
*\n
* A portable \a select() like API (#pj_sock_select()) which can be
* implemented with various back-ends.
*
* - @ref PJ_IOQUEUE
*\n
* Framework for dispatching network events.
*
* For more information see the modules below.
*/
/**
* @defgroup PJ_IOQUEUE IOQueue: I/O Event Dispatching with Proactor Pattern
* @ingroup PJ_IO
* @{
*
* I/O Queue provides API for performing asynchronous I/O operations. It
* conforms to proactor pattern, which allows application to submit an
* asynchronous operation and to be notified later when the operation has
* completed.
*
* The I/O Queue can work on both socket and file descriptors. For
* asynchronous file operations however, one must make sure that the correct
* file I/O back-end is used, because not all file I/O back-end can be
* used with the ioqueue. Please see \ref PJ_FILE_IO for more details.
*
* The framework works natively in platforms where asynchronous operation API
* exists, such as in Windows NT with IoCompletionPort/IOCP. In other
* platforms, the I/O queue abstracts the operating system's event poll API
* to provide semantics similar to IoCompletionPort with minimal penalties
* (i.e. per ioqueue and per handle mutex protection).
*
* The I/O queue provides more than just unified abstraction. It also:
* - makes sure that the operation uses the most effective way to utilize
* the underlying mechanism, to achieve the maximum theoritical
* throughput possible on a given platform.
* - choose the most efficient mechanism for event polling on a given
* platform.
*
* Currently, the I/O Queue is implemented using:
* - <tt><b>select()</b></tt>, as the common denominator, but the least
* efficient. Also the number of descriptor is limited to
* \c PJ_IOQUEUE_MAX_HANDLES (which by default is 64).
* - <tt><b>/dev/epoll</b></tt> on Linux (user mode and kernel mode),
* a much faster replacement for select() on Linux (and more importantly
* doesn't have limitation on number of descriptors).
* - <b>I/O Completion ports</b> on Windows NT/2000/XP, which is the most
* efficient way to dispatch events in Windows NT based OSes, and most
* importantly, it doesn't have the limit on how many handles to monitor.
* And it works with files (not only sockets) as well.
*
*
* \section pj_ioqueue_concurrency_sec Concurrency Rules
*
* The ioqueue has been fine tuned to allow multiple threads to poll the
* handles simultaneously, to maximize scalability when the application is
* running on multiprocessor systems. When more than one threads are polling
* the ioqueue and there are more than one handles are signaled, more than
* one threads will execute the callback simultaneously to serve the events.
* These parallel executions are completely safe when the events happen for
* two different handles.
*
* However, with multithreading, care must be taken when multiple events
* happen on the same handle, or when event is happening on a handle (and
* the callback is being executed) and application is performing
* unregistration to the handle at the same time.
*
* The treatments of above scenario differ according to the concurrency
* setting that are applied to the handle.
*
* \subsection pj_ioq_concur_set Concurrency Settings for Handles
*
* Concurrency can be set on per handle (key) basis, by using
* #pj_ioqueue_set_concurrency() function. The default key concurrency value
* for the handle is inherited from the key concurrency setting of the ioqueue,
* and the key concurrency setting for the ioqueue can be changed by using
* #pj_ioqueue_set_default_concurrency(). The default key concurrency setting
* for ioqueue itself is controlled by compile time setting
* PJ_IOQUEUE_DEFAULT_ALLOW_CONCURRENCY.
*
* Note that this key concurrency setting only controls whether multiple
* threads are allowed to operate <b>on the same key</b> at the same time.
* The ioqueue itself always allows multiple threads to enter the ioqeuue at
* the same time, and also simultaneous callback calls to <b>differrent
* keys</b> is always allowed regardless to the key concurrency setting.
*
* \subsection pj_ioq_parallel Parallel Callback Executions for the Same Handle
*
* Note that when key concurrency is enabled (i.e. parallel callback calls on
* the same key is allowed; this is the default setting), the ioqueue will only
* perform simultaneous callback executions on the same key when the key has
* invoked multiple pending operations. This could be done for example by
* calling #pj_ioqueue_recvfrom() more than once on the same key, each with
* the same key but different operation key (pj_ioqueue_op_key_t). With this
* scenario, when multiple packets arrive on the key at the same time, more
* than one threads may execute the callback simultaneously, each with the
* same key but different operation key.
*
* When there is only one pending operation on the key (e.g. there is only one
* #pj_ioqueue_recvfrom() invoked on the key), then events occuring to the
* same key will be queued by the ioqueue, thus no simultaneous callback calls
* will be performed.
*
* \subsection pj_ioq_allow_concur Concurrency is Enabled (Default Value)
*
* The default setting for the ioqueue is to allow multiple threads to
* execute callbacks for the same handle/key. This setting is selected to
* promote good performance and scalability for application.
*
* However this setting has a major drawback with regard to synchronization,
* and application MUST carefully follow the following guidelines to ensure
* that parallel access to the key does not cause problems:
*
* - Always note that callback may be called simultaneously for the same
* key.
* - <b>Care must be taken when unregistering a key</b> from the
* ioqueue. Application must take care that when one thread is issuing
* an unregistration, other thread is not simultaneously invoking the
* callback <b>to the same key</b>.
*\n
* This happens because the ioqueue functions are working with a pointer
* to the key, and there is a possible race condition where the pointer
* has been rendered invalid by other threads before the ioqueue has a
* chance to acquire mutex on it.
*
* \subsection pj_ioq_disallow_concur Concurrency is Disabled
*
* Alternatively, application may disable key concurrency to make
* synchronization easier. As noted above, there are three ways to control
* key concurrency setting:
* - by controlling on per handle/key basis, with #pj_ioqueue_set_concurrency().
* - by changing default key concurrency setting on the ioqueue, with
* #pj_ioqueue_set_default_concurrency().
* - by changing the default concurrency on compile time, by declaring
* PJ_IOQUEUE_DEFAULT_ALLOW_CONCURRENCY macro to zero in your config_site.h
*
* \section pj_ioqeuue_examples_sec Examples
*
* For some examples on how to use the I/O Queue, please see:
*
* - \ref page_pjlib_ioqueue_tcp_test
* - \ref page_pjlib_ioqueue_udp_test
* - \ref page_pjlib_ioqueue_perf_test
*/
/**
* This structure describes operation specific key to be submitted to
* I/O Queue when performing the asynchronous operation. This key will
* be returned to the application when completion callback is called.
*
* Application normally wants to attach it's specific data in the
* \c user_data field so that it can keep track of which operation has
* completed when the callback is called. Alternatively, application can
* also extend this struct to include its data, because the pointer that
* is returned in the completion callback will be exactly the same as
* the pointer supplied when the asynchronous function is called.
*/
typedef struct pj_ioqueue_op_key_t
{
void *internal__[32]; /**< Internal I/O Queue data. */
void *activesock_data; /**< Active socket data. */
void *user_data; /**< Application data. */
} pj_ioqueue_op_key_t;
/**
* This structure describes the callbacks to be called when I/O operation
* completes.
*/
typedef struct pj_ioqueue_callback
{
/**
* This callback is called when #pj_ioqueue_recv or #pj_ioqueue_recvfrom
* completes.
*
* @param key The key.
* @param op_key Operation key.
* @param bytes_read >= 0 to indicate the amount of data read,
* otherwise negative value containing the error
* code. To obtain the pj_status_t error code, use
* (pj_status_t code = -bytes_read).
*/
void (*on_read_complete)(pj_ioqueue_key_t *key,
pj_ioqueue_op_key_t *op_key,
pj_ssize_t bytes_read);
/**
* This callback is called when #pj_ioqueue_send or #pj_ioqueue_sendto
* completes.
*
* @param key The key.
* @param op_key Operation key.
* @param bytes_sent >= 0 to indicate the amount of data written,
* otherwise negative value containing the error
* code. To obtain the pj_status_t error code, use
* (pj_status_t code = -bytes_sent).
*/
void (*on_write_complete)(pj_ioqueue_key_t *key,
pj_ioqueue_op_key_t *op_key,
pj_ssize_t bytes_sent);
/**
* This callback is called when #pj_ioqueue_accept completes.
*
* @param key The key.
* @param op_key Operation key.
* @param sock Newly connected socket.
* @param status Zero if the operation completes successfully.
*/
void (*on_accept_complete)(pj_ioqueue_key_t *key,
pj_ioqueue_op_key_t *op_key,
pj_sock_t sock,
pj_status_t status);
/**
* This callback is called when #pj_ioqueue_connect completes.
*
* @param key The key.
* @param status PJ_SUCCESS if the operation completes successfully.
*/
void (*on_connect_complete)(pj_ioqueue_key_t *key,
pj_status_t status);
} pj_ioqueue_callback;
/**
* Types of pending I/O Queue operation. This enumeration is only used
* internally within the ioqueue.
*/
typedef enum pj_ioqueue_operation_e
{
PJ_IOQUEUE_OP_NONE = 0, /**< No operation. */
PJ_IOQUEUE_OP_READ = 1, /**< read() operation. */
PJ_IOQUEUE_OP_RECV = 2, /**< recv() operation. */
PJ_IOQUEUE_OP_RECV_FROM = 4, /**< recvfrom() operation. */
PJ_IOQUEUE_OP_WRITE = 8, /**< write() operation. */
PJ_IOQUEUE_OP_SEND = 16, /**< send() operation. */
PJ_IOQUEUE_OP_SEND_TO = 32, /**< sendto() operation. */
#if defined(PJ_HAS_TCP) && PJ_HAS_TCP != 0
PJ_IOQUEUE_OP_ACCEPT = 64, /**< accept() operation. */
PJ_IOQUEUE_OP_CONNECT = 128 /**< connect() operation. */
#endif /* PJ_HAS_TCP */
} pj_ioqueue_operation_e;
/**
* This macro specifies the maximum number of events that can be
* processed by the ioqueue on a single poll cycle, on implementation
* that supports it. The value is only meaningfull when specified
* during PJLIB build.
*/
#ifndef PJ_IOQUEUE_MAX_EVENTS_IN_SINGLE_POLL
# define PJ_IOQUEUE_MAX_EVENTS_IN_SINGLE_POLL (16)
#endif
/**
* This macro specifies the maximum event candidates collected by each
* polling thread to be able to reach maximum number of processed events
* (i.e: PJ_IOQUEUE_MAX_EVENTS_IN_SINGLE_POLL) in each poll cycle.
* An event candidate will be dispatched to application as event unless
* it is already being dispatched by other polling thread. So in order to
* anticipate such race condition, each poll operation should collects its
* event candidates more than PJ_IOQUEUE_MAX_EVENTS_IN_SINGLE_POLL, the
* recommended value is (PJ_IOQUEUE_MAX_EVENTS_IN_SINGLE_POLL *
* number of polling threads).
*
* The value is only meaningfull when specified during PJLIB build and
* is only effective on multiple polling threads environment.
*/
#if !defined(PJ_IOQUEUE_MAX_CAND_EVENTS) || \
PJ_IOQUEUE_MAX_CAND_EVENTS < PJ_IOQUEUE_MAX_EVENTS_IN_SINGLE_POLL
# undef PJ_IOQUEUE_MAX_CAND_EVENTS
# define PJ_IOQUEUE_MAX_CAND_EVENTS PJ_IOQUEUE_MAX_EVENTS_IN_SINGLE_POLL
#endif
/**
* When this flag is specified in ioqueue's recv() or send() operations,
* the ioqueue will always mark the operation as asynchronous.
*/
#define PJ_IOQUEUE_ALWAYS_ASYNC ((pj_uint32_t)1 << (pj_uint32_t)31)
/**
* Return the name of the ioqueue implementation.
*
* @return Implementation name.
*/
PJ_DECL(const char*) pj_ioqueue_name(void);
/**
* Create a new I/O Queue framework.
*
* @param pool The pool to allocate the I/O queue structure.
* @param max_fd The maximum number of handles to be supported, which
* should not exceed PJ_IOQUEUE_MAX_HANDLES.
* @param ioqueue Pointer to hold the newly created I/O Queue.
*
* @return PJ_SUCCESS on success.
*/
PJ_DECL(pj_status_t) pj_ioqueue_create( pj_pool_t *pool,
pj_size_t max_fd,
pj_ioqueue_t **ioqueue);
/**
* Destroy the I/O queue.
*
* @param ioque The I/O Queue to be destroyed.
*
* @return PJ_SUCCESS if success.
*/
PJ_DECL(pj_status_t) pj_ioqueue_destroy( pj_ioqueue_t *ioque );
/**
* Set the lock object to be used by the I/O Queue. This function can only
* be called right after the I/O queue is created, before any handle is
* registered to the I/O queue.
*
* Initially the I/O queue is created with non-recursive mutex protection.
* Applications can supply alternative lock to be used by calling this
* function.
*
* @param ioque The ioqueue instance.
* @param lock The lock to be used by the ioqueue.
* @param auto_delete In non-zero, the lock will be deleted by the ioqueue.
*
* @return PJ_SUCCESS or the appropriate error code.
*/
PJ_DECL(pj_status_t) pj_ioqueue_set_lock( pj_ioqueue_t *ioque,
pj_lock_t *lock,
pj_bool_t auto_delete );
/**
* Set default concurrency policy for this ioqueue. If this function is not
* called, the default concurrency policy for the ioqueue is controlled by
* compile time setting PJ_IOQUEUE_DEFAULT_ALLOW_CONCURRENCY.
*
* Note that changing the concurrency setting to the ioqueue will only affect
* subsequent key registrations. To modify the concurrency setting for
* individual key, use #pj_ioqueue_set_concurrency().
*
* @param ioqueue The ioqueue instance.
* @param allow Non-zero to allow concurrent callback calls, or
* PJ_FALSE to disallow it.
*
* @return PJ_SUCCESS on success or the appropriate error code.
*/
PJ_DECL(pj_status_t) pj_ioqueue_set_default_concurrency(pj_ioqueue_t *ioqueue,
pj_bool_t allow);
/**
* Register a socket to the I/O queue framework.
* When a socket is registered to the IOQueue, it may be modified to use
* non-blocking IO. If it is modified, there is no guarantee that this
* modification will be restored after the socket is unregistered.
*
* @param pool To allocate the resource for the specified handle,
* which must be valid until the handle/key is unregistered
* from I/O Queue.
* @param ioque The I/O Queue.
* @param sock The socket.
* @param user_data User data to be associated with the key, which can be
* retrieved later.
* @param cb Callback to be called when I/O operation completes.
* @param key Pointer to receive the key to be associated with this
* socket. Subsequent I/O queue operation will need this
* key.
*
* @return PJ_SUCCESS on success, or the error code.
*/
PJ_DECL(pj_status_t) pj_ioqueue_register_sock( pj_pool_t *pool,
pj_ioqueue_t *ioque,
pj_sock_t sock,
void *user_data,
const pj_ioqueue_callback *cb,
pj_ioqueue_key_t **key );
/**
* Variant of pj_ioqueue_register_sock() with additional group lock parameter.
* If group lock is set for the key, the key will add the reference counter
* when the socket is registered and decrease it when it is destroyed.
*/
PJ_DECL(pj_status_t) pj_ioqueue_register_sock2(pj_pool_t *pool,
pj_ioqueue_t *ioque,
pj_sock_t sock,
pj_grp_lock_t *grp_lock,
void *user_data,
const pj_ioqueue_callback *cb,
pj_ioqueue_key_t **key );
/**
* Unregister from the I/O Queue framework. Caller must make sure that
* the key doesn't have any pending operations before calling this function,
* by calling #pj_ioqueue_is_pending() for all previously submitted
* operations except asynchronous connect, and if necessary call
* #pj_ioqueue_post_completion() to cancel the pending operations.
*
* Note that asynchronous connect operation will automatically be
* cancelled during the unregistration.
*
* Also note that when I/O Completion Port backend is used, application
* MUST close the handle immediately after unregistering the key. This is
* because there is no unregistering API for IOCP. The only way to
* unregister the handle from IOCP is to close the handle.
*
* @param key The key that was previously obtained from registration.
*
* @return PJ_SUCCESS on success or the error code.
*
* @see pj_ioqueue_is_pending
*/
PJ_DECL(pj_status_t) pj_ioqueue_unregister( pj_ioqueue_key_t *key );
/**
* Get user data associated with an ioqueue key.
*
* @param key The key that was previously obtained from registration.
*
* @return The user data associated with the descriptor, or NULL
* on error or if no data is associated with the key during
* registration.
*/
PJ_DECL(void*) pj_ioqueue_get_user_data( pj_ioqueue_key_t *key );
/**
* Set or change the user data to be associated with the file descriptor or
* handle or socket descriptor.
*
* @param key The key that was previously obtained from registration.
* @param user_data User data to be associated with the descriptor.
* @param old_data Optional parameter to retrieve the old user data.
*
* @return PJ_SUCCESS on success or the error code.
*/
PJ_DECL(pj_status_t) pj_ioqueue_set_user_data( pj_ioqueue_key_t *key,
void *user_data,
void **old_data);
/**
* Configure whether the ioqueue is allowed to call the key's callback
* concurrently/in parallel. The default concurrency setting for the key
* is controlled by ioqueue's default concurrency value, which can be
* changed by calling #pj_ioqueue_set_default_concurrency().
*
* If concurrency is allowed for the key, it means that if there are more
* than one pending operations complete simultaneously, more than one
* threads may call the key's callback at the same time. This generally
* would promote good scalability for application, at the expense of more
* complexity to manage the concurrent accesses in application's code.
*
* Alternatively application may disable the concurrent access by
* setting the \a allow flag to false. With concurrency disabled, only
* one thread can call the key's callback at one time.
*
* @param key The key that was previously obtained from registration.
* @param allow Set this to non-zero to allow concurrent callback calls
* and zero (PJ_FALSE) to disallow it.
*
* @return PJ_SUCCESS on success or the appropriate error code.
*/
PJ_DECL(pj_status_t) pj_ioqueue_set_concurrency(pj_ioqueue_key_t *key,
pj_bool_t allow);
/**
* Acquire the key's mutex. When the key's concurrency is disabled,
* application may call this function to synchronize its operation
* with the key's callback (i.e. this function will block until the
* key's callback returns).
*
* @param key The key that was previously obtained from registration.
*
* @return PJ_SUCCESS on success or the appropriate error code.
*/
PJ_DECL(pj_status_t) pj_ioqueue_lock_key(pj_ioqueue_key_t *key);
/**
* Try to acquire the key's mutex. When the key's concurrency is disabled,
* application may call this function to synchronize its operation
* with the key's callback.
*
* @param key The key that was previously obtained from registration.
*
* @return PJ_SUCCESS on success or the appropriate error code.
*/
PJ_DECL(pj_status_t) pj_ioqueue_trylock_key(pj_ioqueue_key_t *key);
/**
* Release the lock previously acquired with pj_ioqueue_lock_key().
*
* @param key The key that was previously obtained from registration.
*
* @return PJ_SUCCESS on success or the appropriate error code.
*/
PJ_DECL(pj_status_t) pj_ioqueue_unlock_key(pj_ioqueue_key_t *key);
/**
* Initialize operation key.
*
* @param op_key The operation key to be initialied.
* @param size The size of the operation key.
*/
PJ_DECL(void) pj_ioqueue_op_key_init( pj_ioqueue_op_key_t *op_key,
pj_size_t size );
/**
* Check if operation is pending on the specified operation key.
* The \c op_key must have been initialized with #pj_ioqueue_op_key_init()
* or submitted as pending operation before, or otherwise the result
* is undefined.
*
* @param key The key.
* @param op_key The operation key, previously submitted to any of
* the I/O functions and has returned PJ_EPENDING.
*
* @return Non-zero if operation is still pending.
*/
PJ_DECL(pj_bool_t) pj_ioqueue_is_pending( pj_ioqueue_key_t *key,
pj_ioqueue_op_key_t *op_key );
/**
* Post completion status to the specified operation key and call the
* appropriate callback. When the callback is called, the number of bytes
* received in read/write callback or the status in accept/connect callback
* will be set from the \c bytes_status parameter.
*
* @param key The key.
* @param op_key Pending operation key.
* @param bytes_status Number of bytes or status to be set. A good value
* to put here is -PJ_ECANCELLED.
*
* @return PJ_SUCCESS if completion status has been successfully
* sent.
*/
PJ_DECL(pj_status_t) pj_ioqueue_post_completion( pj_ioqueue_key_t *key,
pj_ioqueue_op_key_t *op_key,
pj_ssize_t bytes_status );
#if defined(PJ_HAS_TCP) && PJ_HAS_TCP != 0
/**
* Instruct I/O Queue to accept incoming connection on the specified
* listening socket. This function will return immediately (i.e. non-blocking)
* regardless whether a connection is immediately available. If the function
* can't complete immediately, the caller will be notified about the incoming
* connection when it calls pj_ioqueue_poll(). If a new connection is
* immediately available, the function returns PJ_SUCCESS with the new
* connection; in this case, the callback WILL NOT be called.
*
* @param key The key which registered to the server socket.
* @param op_key An operation specific key to be associated with the
* pending operation, so that application can keep track of
* which operation has been completed when the callback is
* called.
* @param new_sock Argument which contain pointer to receive the new socket
* for the incoming connection.
* @param local Optional argument which contain pointer to variable to
* receive local address.
* @param remote Optional argument which contain pointer to variable to
* receive the remote address.
* @param addrlen On input, contains the length of the buffer for the
* address, and on output, contains the actual length of the
* address. This argument is optional.
* @return
* - PJ_SUCCESS When connection is available immediately, and the
* parameters will be updated to contain information about
* the new connection. In this case, a completion callback
* WILL NOT be called.
* - PJ_EPENDING If no connection is available immediately. When a new
* connection arrives, the callback will be called.
* - non-zero which indicates the appropriate error code.
*/
PJ_DECL(pj_status_t) pj_ioqueue_accept( pj_ioqueue_key_t *key,
pj_ioqueue_op_key_t *op_key,
pj_sock_t *new_sock,
pj_sockaddr_t *local,
pj_sockaddr_t *remote,
int *addrlen );
/**
* Initiate non-blocking socket connect. If the socket can NOT be connected
* immediately, asynchronous connect() will be scheduled and caller will be
* notified via completion callback when it calls pj_ioqueue_poll(). If
* socket is connected immediately, the function returns PJ_SUCCESS and
* completion callback WILL NOT be called.
*
* @param key The key associated with TCP socket
* @param addr The remote address.
* @param addrlen The remote address length.
*
* @return
* - PJ_SUCCESS If socket is connected immediately. In this case, the
* completion callback WILL NOT be called.
* - PJ_EPENDING If operation is queued, or
* - non-zero Indicates the error code.
*/
PJ_DECL(pj_status_t) pj_ioqueue_connect( pj_ioqueue_key_t *key,
const pj_sockaddr_t *addr,
int addrlen );
#endif /* PJ_HAS_TCP */
/**
* Poll the I/O Queue for completed events.
*
* Note: polling the ioqueue is not necessary in Symbian. Please see
* @ref PJ_SYMBIAN_OS for more info.
*
* @param ioque the I/O Queue.
* @param timeout polling timeout, or NULL if the thread wishes to wait
* indefinetely for the event.
*
* @return
* - zero if timed out (no event).
* - (<0) if error occured during polling. Callback will NOT be called.
* - (>1) to indicate numbers of events. Callbacks have been called.
*/
PJ_DECL(int) pj_ioqueue_poll( pj_ioqueue_t *ioque,
const pj_time_val *timeout);
/**
* Instruct the I/O Queue to read from the specified handle. This function
* returns immediately (i.e. non-blocking) regardless whether some data has
* been transferred. If the operation can't complete immediately, caller will
* be notified about the completion when it calls pj_ioqueue_poll(). If data
* is immediately available, the function will return PJ_SUCCESS and the
* callback WILL NOT be called.
*
* @param key The key that uniquely identifies the handle.
* @param op_key An operation specific key to be associated with the
* pending operation, so that application can keep track of
* which operation has been completed when the callback is
* called. Caller must make sure that this key remains
* valid until the function completes.
* @param buffer The buffer to hold the read data. The caller MUST make sure
* that this buffer remain valid until the framework completes
* reading the handle.
* @param length On input, it specifies the size of the buffer. If data is
* available to be read immediately, the function returns
* PJ_SUCCESS and this argument will be filled with the
* amount of data read. If the function is pending, caller
* will be notified about the amount of data read in the
* callback. This parameter can point to local variable in
* caller's stack and doesn't have to remain valid for the
* duration of pending operation.
* @param flags Recv flag. If flags has PJ_IOQUEUE_ALWAYS_ASYNC then
* the function will never return PJ_SUCCESS.
*
* @return
* - PJ_SUCCESS If immediate data has been received in the buffer. In this
* case, the callback WILL NOT be called.
* - PJ_EPENDING If the operation has been queued, and the callback will be
* called when data has been received.
* - non-zero The return value indicates the error code.
*/
PJ_DECL(pj_status_t) pj_ioqueue_recv( pj_ioqueue_key_t *key,
pj_ioqueue_op_key_t *op_key,
void *buffer,
pj_ssize_t *length,
pj_uint32_t flags );
/**
* This function behaves similarly as #pj_ioqueue_recv(), except that it is
* normally called for socket, and the remote address will also be returned
* along with the data. Caller MUST make sure that both buffer and addr
* remain valid until the framework completes reading the data.
*
* @param key The key that uniquely identifies the handle.
* @param op_key An operation specific key to be associated with the
* pending operation, so that application can keep track of
* which operation has been completed when the callback is
* called.
* @param buffer The buffer to hold the read data. The caller MUST make sure
* that this buffer remain valid until the framework completes
* reading the handle.
* @param length On input, it specifies the size of the buffer. If data is
* available to be read immediately, the function returns
* PJ_SUCCESS and this argument will be filled with the
* amount of data read. If the function is pending, caller
* will be notified about the amount of data read in the
* callback. This parameter can point to local variable in
* caller's stack and doesn't have to remain valid for the
* duration of pending operation.
* @param flags Recv flag. If flags has PJ_IOQUEUE_ALWAYS_ASYNC then
* the function will never return PJ_SUCCESS.
* @param addr Optional Pointer to buffer to receive the address.
* @param addrlen On input, specifies the length of the address buffer.
* On output, it will be filled with the actual length of
* the address. This argument can be NULL if \c addr is not
* specified.
*
* @return
* - PJ_SUCCESS If immediate data has been received. In this case, the
* callback must have been called before this function
* returns, and no pending operation is scheduled.
* - PJ_EPENDING If the operation has been queued.
* - non-zero The return value indicates the error code.
*/
PJ_DECL(pj_status_t) pj_ioqueue_recvfrom( pj_ioqueue_key_t *key,
pj_ioqueue_op_key_t *op_key,
void *buffer,
pj_ssize_t *length,
pj_uint32_t flags,
pj_sockaddr_t *addr,
int *addrlen);
/**
* Instruct the I/O Queue to write to the handle. This function will return
* immediately (i.e. non-blocking) regardless whether some data has been
* transferred. If the function can't complete immediately, the caller will
* be notified about the completion when it calls pj_ioqueue_poll(). If
* operation completes immediately and data has been transferred, the function
* returns PJ_SUCCESS and the callback will NOT be called.
*
* @param key The key that identifies the handle.
* @param op_key An operation specific key to be associated with the
* pending operation, so that application can keep track of
* which operation has been completed when the callback is
* called.
* @param data The data to send. Caller MUST make sure that this buffer
* remains valid until the write operation completes.
* @param length On input, it specifies the length of data to send. When
* data was sent immediately, this function returns PJ_SUCCESS
* and this parameter contains the length of data sent. If
* data can not be sent immediately, an asynchronous operation
* is scheduled and caller will be notified via callback the
* number of bytes sent. This parameter can point to local
* variable on caller's stack and doesn't have to remain
* valid until the operation has completed.
* @param flags Send flags. If flags has PJ_IOQUEUE_ALWAYS_ASYNC then
* the function will never return PJ_SUCCESS.
*
* @return
* - PJ_SUCCESS If data was immediately transferred. In this case, no
* pending operation has been scheduled and the callback
* WILL NOT be called.
* - PJ_EPENDING If the operation has been queued. Once data base been
* transferred, the callback will be called.
* - non-zero The return value indicates the error code.
*/
PJ_DECL(pj_status_t) pj_ioqueue_send( pj_ioqueue_key_t *key,
pj_ioqueue_op_key_t *op_key,
const void *data,
pj_ssize_t *length,
pj_uint32_t flags );
/**
* Instruct the I/O Queue to write to the handle. This function will return
* immediately (i.e. non-blocking) regardless whether some data has been
* transferred. If the function can't complete immediately, the caller will
* be notified about the completion when it calls pj_ioqueue_poll(). If
* operation completes immediately and data has been transferred, the function
* returns PJ_SUCCESS and the callback will NOT be called.
*
* @param key the key that identifies the handle.
* @param op_key An operation specific key to be associated with the
* pending operation, so that application can keep track of
* which operation has been completed when the callback is
* called.
* @param data the data to send. Caller MUST make sure that this buffer
* remains valid until the write operation completes.
* @param length On input, it specifies the length of data to send. When
* data was sent immediately, this function returns PJ_SUCCESS
* and this parameter contains the length of data sent. If
* data can not be sent immediately, an asynchronous operation
* is scheduled and caller will be notified via callback the
* number of bytes sent. This parameter can point to local
* variable on caller's stack and doesn't have to remain
* valid until the operation has completed.
* @param flags send flags. If flags has PJ_IOQUEUE_ALWAYS_ASYNC then
* the function will never return PJ_SUCCESS.
* @param addr Optional remote address.
* @param addrlen Remote address length, \c addr is specified.
*
* @return
* - PJ_SUCCESS If data was immediately written.
* - PJ_EPENDING If the operation has been queued.
* - non-zero The return value indicates the error code.
*/
PJ_DECL(pj_status_t) pj_ioqueue_sendto( pj_ioqueue_key_t *key,
pj_ioqueue_op_key_t *op_key,
const void *data,
pj_ssize_t *length,
pj_uint32_t flags,
const pj_sockaddr_t *addr,
int addrlen);
/**
* !}
*/
PJ_END_DECL
#endif /* __PJ_IOQUEUE_H__ */
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