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| -rw-r--r-- | nsprpub/pr/include/prmwait.h | 380 |
1 files changed, 380 insertions, 0 deletions
diff --git a/nsprpub/pr/include/prmwait.h b/nsprpub/pr/include/prmwait.h new file mode 100644 index 0000000000..16c0762199 --- /dev/null +++ b/nsprpub/pr/include/prmwait.h @@ -0,0 +1,380 @@ +/* -*- Mode: C++; tab-width: 4; 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/. */ + +#if defined(_PRMWAIT_H) +#else +#define _PRMWAIT_H + +#include "prio.h" +#include "prtypes.h" +#include "prclist.h" + +PR_BEGIN_EXTERN_C + +/********************************************************************************/ +/********************************************************************************/ +/********************************************************************************/ +/****************************** WARNING ****************************/ +/********************************************************************************/ +/**************************** This is work in progress. *************************/ +/************************** Do not make any assumptions *************************/ +/************************** about the stability of this *************************/ +/************************** API or the underlying imple- ************************/ +/************************** mentation. ************************/ +/********************************************************************************/ +/********************************************************************************/ + +/* +** STRUCTURE: PRWaitGroup +** DESCRIPTION: +** The client may define several wait groups in order to semantically +** tie a collection of file descriptors for a single purpose. This allows +** easier dispatching of threads that returned with active file descriptors +** from the wait function. +*/ +typedef struct PRWaitGroup PRWaitGroup; + +/* +** ENUMERATION: PRMWStatus +** DESCRIPTION: +** This enumeration is used to indicate the completion status of +** a receive wait object. Generally stated, a positive value indicates +** that the operation is not yet complete. A zero value indicates +** success (similar to PR_SUCCESS) and any negative value is an +** indication of failure. The reason for the failure can be retrieved +** by calling PR_GetError(). +** +** PR_MW_PENDING The operation is still pending. None of the other +** fields of the object are currently valid. +** PR_MW_SUCCESS The operation is complete and it was successful. +** PR_MW_FAILURE The operation failed. The reason for the failure +** can be retrieved by calling PR_GetError(). +** PR_MW_TIMEOUT The amount of time allowed for by the object's +** 'timeout' field has expired w/o the operation +** otherwise coming to closure. +** PR_MW_INTERRUPT The operation was cancelled, either by the client +** calling PR_CancelWaitFileDesc() or destroying the +** entire wait group (PR_DestroyWaitGroup()). +*/ +typedef enum PRMWStatus +{ + PR_MW_PENDING = 1, + PR_MW_SUCCESS = 0, + PR_MW_FAILURE = -1, + PR_MW_TIMEOUT = -2, + PR_MW_INTERRUPT = -3 +} PRMWStatus; + +/* +** STRUCTURE: PRMemoryDescriptor +** DESCRIPTION: +** THis is a descriptor for an interval of memory. It contains a +** pointer to the first byte of that memory and the length (in +** bytes) of the interval. +*/ +typedef struct PRMemoryDescriptor +{ + void *start; /* pointer to first byte of memory */ + PRSize length; /* length (in bytes) of memory interval */ +} PRMemoryDescriptor; + +/* +** STRUCTURE: PRMWaitClientData +** DESCRIPTION: +** An opague stucture for which a client MAY give provide a concrete +** definition and associate with a receive descriptor. The NSPR runtime +** does not manage this field. It is completely up to the client. +*/ +typedef struct PRMWaitClientData PRMWaitClientData; + +/* +** STRUCTURE: PRRecvWait +** DESCRIPTION: +** A receive wait object contains the file descriptor that is subject +** to the wait and the amount of time (beginning epoch established +** when the object is presented to the runtime) the the channel should +** block before abandoning the process. +** +** The success of the wait operation will be noted in the object's +** 'outcome' field. The fields are not valid when the NSPR runtime +** is in possession of the object. +** +** The memory descriptor describes an interval of writable memory +** in the caller's address space where data from an initial read +** can be placed. The description may indicate a null interval. +*/ +typedef struct PRRecvWait +{ + PRCList internal; /* internal runtime linkages */ + + PRFileDesc *fd; /* file descriptor associated w/ object */ + PRMWStatus outcome; /* outcome of the current/last operation */ + PRIntervalTime timeout; /* time allowed for entire operation */ + + PRInt32 bytesRecv; /* number of bytes transferred into buffer */ + PRMemoryDescriptor buffer; /* where to store first segment of input data */ + PRMWaitClientData *client; /* pointer to arbitrary client defined data */ +} PRRecvWait; + +/* +** STRUCTURE: PRMWaitEnumerator +** DESCRIPTION: +** An enumeration object is used to store the state of an existing +** enumeration over a wait group. The opaque object must be allocated +** by the client and the reference presented on each call to the +** pseudo-stateless enumerator. The enumeration objects are sharable +** only in serial fashion. +*/ +typedef struct PRMWaitEnumerator PRMWaitEnumerator; + + +/* +** FUNCTION: PR_AddWaitFileDesc +** DESCRIPTION: +** This function will effectively add a file descriptor to the +** list of those waiting for network receive. The new descriptor +** will be semantically tied to the wait group specified. +** +** The ownership for the storage pointed to by 'desc' is temporarily +** passed over the the NSPR runtime. It will be handed back by the +** function PR_WaitRecvReady(). +** +** INPUTS +** group A reference to a PRWaitGroup or NULL. Wait groups are +** created by calling PR_CreateWaitGroup() and are used +** to semantically group various file descriptors by the +** client's application. +** desc A reference to a valid PRRecvWait. The object of the +** reference must be preserved and not be modified +** until its ownership is returned to the client. +** RETURN +** PRStatus An indication of success. If equal to PR_FAILUE details +** of the failure are avaiable via PR_GetError(). +** +** ERRORS +** PR_INVALID_ARGUMENT_ERROR +** Invalid 'group' identifier or duplicate 'desc' object. +** PR_OUT_OF_MEMORY_ERROR +** Insuffient memory for internal data structures. +** PR_INVALID_STATE_ERROR +** The group is being destroyed. +*/ +NSPR_API(PRStatus) PR_AddWaitFileDesc(PRWaitGroup *group, PRRecvWait *desc); + +/* +** FUNCTION: PR_WaitRecvReady +** DESCRIPTION: +** PR_WaitRecvReady will block the calling thread until one of the +** file descriptors that have been added via PR_AddWaitFileDesc is +** available for input I/O. +** INPUT +** group A pointer to a valid PRWaitGroup or NULL (the null +** group. The function will block the caller until a +** channel from the wait group becomes ready for receive +** or there is some sort of error. +** RETURN +** PRReciveWait +** When the caller is resumed it is either returned a +** valid pointer to a previously added receive wait or +** a NULL. If the latter, the function has terminated +** for a reason that can be determined by calling +** PR_GetError(). +** If a valid pointer is returned, the reference is to the +** file descriptor contained in the receive wait object. +** The outcome of the wait operation may still fail, and +** if it has, that fact will be noted in the object's +** outcome field. Details can be retrieved from PR_GetError(). +** +** ERRORS +** PR_INVALID_ARGUMENT_ERROR +** The 'group' is not known by the runtime. +** PR_PENDING_INTERRUPT_ERROR + The thread was interrupted. +** PR_INVALID_STATE_ERROR +** The group is being destroyed. +*/ +NSPR_API(PRRecvWait*) PR_WaitRecvReady(PRWaitGroup *group); + +/* +** FUNCTION: PR_CancelWaitFileDesc +** DESCRIPTION: +** PR_CancelWaitFileDesc is provided as a means for cancelling operations +** on objects previously submitted by use of PR_AddWaitFileDesc(). If +** the runtime knows of the object, it will be marked as having failed +** because it was interrupted (similar to PR_Interrupt()). The first +** available thread waiting on the group will be made to return the +** PRRecvWait object with the outcome noted. +** +** INPUTS +** group The wait group under which the wait receive object was +** added. +** desc A pointer to the wait receive object that is to be +** cancelled. +** RETURN +** PRStatus If the wait receive object was located and associated +** with the specified wait group, the status returned will +** be PR_SUCCESS. There is still a race condition that would +** permit the offected object to complete normally, but it +** is assured that it will complete in the near future. +** If the receive object or wait group are invalid, the +** function will return with a status of PR_FAILURE. +** +** ERRORS +** PR_INVALID_ARGUMENT_ERROR +** The 'group' argument is not recognized as a valid group. +** PR_COLLECTION_EMPTY_ERROR +** There are no more receive wait objects in the group's +** collection. +** PR_INVALID_STATE_ERROR +** The group is being destroyed. +*/ +NSPR_API(PRStatus) PR_CancelWaitFileDesc(PRWaitGroup *group, PRRecvWait *desc); + +/* +** FUNCTION: PR_CancelWaitGroup +** DESCRIPTION: +** PR_CancelWaitGroup is provided as a means for cancelling operations +** on objects previously submitted by use of PR_AddWaitFileDesc(). Each +** successive call will return a pointer to a PRRecvWait object that +** was previously registered via PR_AddWaitFileDesc(). If no wait +** objects are associated with the wait group, a NULL will be returned. +** This function should be called in a loop until a NULL is returned +** to reclaim all the wait objects prior to calling PR_DestroyWaitGroup(). +** +** INPUTS +** group The wait group under which the wait receive object was +** added. +** RETURN +** PRRecvWait* If the wait group is valid and at least one receive wait +** object is present in the group, that object will be +** marked as PR_MW_INTERRUPT'd and removed from the group's +** queues. Otherwise a NULL will be returned and the reason +** for the NULL may be retrieved by calling PR_GetError(). +** +** ERRORS +** PR_INVALID_ARGUMENT_ERROR +** PR_GROUP_EMPTY_ERROR +*/ +NSPR_API(PRRecvWait*) PR_CancelWaitGroup(PRWaitGroup *group); + +/* +** FUNCTION: PR_CreateWaitGroup +** DESCRIPTION: +** A wait group is an opaque object that a client may create in order +** to semantically group various wait requests. Each wait group is +** unique, including the default wait group (NULL). A wait request +** that was added under a wait group will only be serviced by a caller +** that specified the same wait group. +** +** INPUT +** size The size of the hash table to be used to contain the +** receive wait objects. This is just the initial size. +** It will grow as it needs to, but to avoid that hassle +** one can suggest a suitable size initially. It should +** be ~30% larger than the maximum number of receive wait +** objects expected. +** RETURN +** PRWaitGroup If successful, the function will return a pointer to an +** object that was allocated by and owned by the runtime. +** The reference remains valid until it is explicitly destroyed +** by calling PR_DestroyWaitGroup(). +** +** ERRORS +** PR_OUT_OF_MEMORY_ERROR +*/ +NSPR_API(PRWaitGroup*) PR_CreateWaitGroup(PRInt32 size); + +/* +** FUNCTION: PR_DestroyWaitGroup +** DESCRIPTION: +** Undo the effects of PR_CreateWaitGroup(). Any receive wait operations +** on the group will be treated as if the each had been the target of a +** PR_CancelWaitFileDesc(). +** +** INPUT +** group Reference to a wait group previously allocated using +** PR_CreateWaitGroup(). +** RETURN +** PRStatus Will be PR_SUCCESS if the wait group was valid and there +** are no receive wait objects in that group. Otherwise +** will indicate PR_FAILURE. +** +** ERRORS +** PR_INVALID_ARGUMENT_ERROR +** The 'group' argument does not reference a known object. +** PR_INVALID_STATE_ERROR +** The group still contains receive wait objects. +*/ +NSPR_API(PRStatus) PR_DestroyWaitGroup(PRWaitGroup *group); + +/* +** FUNCTION: PR_CreateMWaitEnumerator +** DESCRIPTION: +** The PR_CreateMWaitEnumerator() function returns a reference to an +** opaque PRMWaitEnumerator object. The enumerator object is required +** as an argument for each successive call in the stateless enumeration +** of the indicated wait group. +** +** group The wait group that the enumeration is intended to +** process. It may be be the default wait group (NULL). +** RETURN +** PRMWaitEnumerator* group +** A reference to an object that will be used to store +** intermediate state of enumerations. +** ERRORS +** Errors are indicated by the function returning a NULL. +** PR_INVALID_ARGUMENT_ERROR +** The 'group' argument does not reference a known object. +** PR_OUT_OF_MEMORY_ERROR +*/ +NSPR_API(PRMWaitEnumerator*) PR_CreateMWaitEnumerator(PRWaitGroup *group); + +/* +** FUNCTION: PR_DestroyMWaitEnumerator +** DESCRIPTION: +** Destroys the object created by PR_CreateMWaitEnumerator(). The reference +** used as an argument becomes invalid. +** +** INPUT +** PRMWaitEnumerator* enumerator +** The PRMWaitEnumerator object to destroy. +** RETURN +** PRStatus +** PR_SUCCESS if successful, PR_FAILURE otherwise. +** ERRORS +** PR_INVALID_ARGUMENT_ERROR +** The enumerator is invalid. +*/ +NSPR_API(PRStatus) PR_DestroyMWaitEnumerator(PRMWaitEnumerator* enumerator); + +/* +** FUNCTION: PR_EnumerateWaitGroup +** DESCRIPTION: +** PR_EnumerateWaitGroup is a thread safe enumerator over a wait group. +** Each call to the enumerator must present a valid PRMWaitEnumerator +** rererence and a pointer to the "previous" element returned from the +** enumeration process or a NULL. +** +** An enumeration is started by passing a NULL as the "previous" value. +** Subsequent calls to the enumerator must pass in the result of the +** previous call. The enumeration end is signaled by the runtime returning +** a NULL as the result. +** +** Modifications to the content of the wait group are allowed during +** an enumeration. The effect is that the enumeration may have to be +** "reset" and that may result in duplicates being returned from the +** enumeration. +** +** An enumeration may be abandoned at any time. The runtime is not +** keeping any state, so there are no issues in that regard. +*/ +NSPR_API(PRRecvWait*) PR_EnumerateWaitGroup( + PRMWaitEnumerator *enumerator, const PRRecvWait *previous); + +PR_END_EXTERN_C + +#endif /* defined(_PRMWAIT_H) */ + +/* prmwait.h */ |