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Annotation of sbbs/javascript/include/mozilla/nspr/prthread.h, revision 1.1

1.1     ! root        1: /* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
        !             2: /* 
        !             3:  * The contents of this file are subject to the Mozilla Public
        !             4:  * License Version 1.1 (the "License"); you may not use this file
        !             5:  * except in compliance with the License. You may obtain a copy of
        !             6:  * the License at http://www.mozilla.org/MPL/
        !             7:  * 
        !             8:  * Software distributed under the License is distributed on an "AS
        !             9:  * IS" basis, WITHOUT WARRANTY OF ANY KIND, either express or
        !            10:  * implied. See the License for the specific language governing
        !            11:  * rights and limitations under the License.
        !            12:  * 
        !            13:  * The Original Code is the Netscape Portable Runtime (NSPR).
        !            14:  * 
        !            15:  * The Initial Developer of the Original Code is Netscape
        !            16:  * Communications Corporation.  Portions created by Netscape are 
        !            17:  * Copyright (C) 1998-2000 Netscape Communications Corporation.  All
        !            18:  * Rights Reserved.
        !            19:  * 
        !            20:  * Contributor(s):
        !            21:  * 
        !            22:  * Alternatively, the contents of this file may be used under the
        !            23:  * terms of the GNU General Public License Version 2 or later (the
        !            24:  * "GPL"), in which case the provisions of the GPL are applicable 
        !            25:  * instead of those above.  If you wish to allow use of your 
        !            26:  * version of this file only under the terms of the GPL and not to
        !            27:  * allow others to use your version of this file under the MPL,
        !            28:  * indicate your decision by deleting the provisions above and
        !            29:  * replace them with the notice and other provisions required by
        !            30:  * the GPL.  If you do not delete the provisions above, a recipient
        !            31:  * may use your version of this file under either the MPL or the
        !            32:  * GPL.
        !            33:  */
        !            34: 
        !            35: #ifndef prthread_h___
        !            36: #define prthread_h___
        !            37: 
        !            38: /*
        !            39: ** API for NSPR threads. On some architectures (MAC and WIN16
        !            40: ** notably) pre-emptibility is not guaranteed. Hard priority scheduling
        !            41: ** is not guaranteed, so programming using priority based synchronization
        !            42: ** is a no-no.
        !            43: **
        !            44: ** NSPR threads are scheduled based loosly on their client set priority.
        !            45: ** In general, a thread of a higher priority has a statistically better
        !            46: ** chance of running relative to threads of lower priority. However,
        !            47: ** NSPR uses multiple strategies to provide execution vehicles for thread
        !            48: ** abstraction of various host platforms. As it turns out, there is little
        !            49: ** NSPR can do to affect the scheduling attributes of "GLOBAL" threads.
        !            50: ** However, a semblance of GLOBAL threads is used to implement "LOCAL"
        !            51: ** threads. An arbitrary number of such LOCAL threads can be assigned to
        !            52: ** a single GLOBAL thread.
        !            53: **
        !            54: ** For scheduling, NSPR will attempt to run the highest priority LOCAL
        !            55: ** thread associated with a given GLOBAL thread. It is further assumed
        !            56: ** that the host OS will apply some form of "fair" scheduling on the
        !            57: ** GLOBAL threads.
        !            58: **
        !            59: ** Threads have a "system flag" which when set indicates the thread
        !            60: ** doesn't count for determining when the process should exit (the
        !            61: ** process exits when the last user thread exits).
        !            62: **
        !            63: ** Threads also have a "scope flag" which controls whether the threads
        !            64: ** are scheduled in the local scope or scheduled by the OS globally. This 
        !            65: ** indicates whether a thread is permanently bound to a native OS thread. 
        !            66: ** An unbound thread competes for scheduling resources in the same process.
        !            67: **
        !            68: ** Another flag is "state flag" which control whether the thread is joinable.
        !            69: ** It allows other threads to wait for the created thread to reach completion.
        !            70: **
        !            71: ** Threads can have "per-thread-data" attached to them. Each thread has a
        !            72: ** per-thread error number and error string which are updated when NSPR
        !            73: ** operations fail.
        !            74: */
        !            75: #include "prtypes.h"
        !            76: #include "prinrval.h"
        !            77: 
        !            78: PR_BEGIN_EXTERN_C
        !            79: 
        !            80: typedef struct PRThread PRThread;
        !            81: typedef struct PRThreadStack PRThreadStack;
        !            82: 
        !            83: typedef enum PRThreadType {
        !            84:     PR_USER_THREAD,
        !            85:     PR_SYSTEM_THREAD
        !            86: } PRThreadType;
        !            87: 
        !            88: typedef enum PRThreadScope {
        !            89:     PR_LOCAL_THREAD,
        !            90:     PR_GLOBAL_THREAD,
        !            91:     PR_GLOBAL_BOUND_THREAD
        !            92: } PRThreadScope;
        !            93: 
        !            94: typedef enum PRThreadState {
        !            95:     PR_JOINABLE_THREAD,
        !            96:     PR_UNJOINABLE_THREAD
        !            97: } PRThreadState;
        !            98: 
        !            99: typedef enum PRThreadPriority
        !           100: {
        !           101:     PR_PRIORITY_FIRST = 0,      /* just a placeholder */
        !           102:     PR_PRIORITY_LOW = 0,        /* the lowest possible priority */
        !           103:     PR_PRIORITY_NORMAL = 1,     /* most common expected priority */
        !           104:     PR_PRIORITY_HIGH = 2,       /* slightly more aggressive scheduling */
        !           105:     PR_PRIORITY_URGENT = 3,     /* it does little good to have more than one */
        !           106:     PR_PRIORITY_LAST = 3        /* this is just a placeholder */
        !           107: } PRThreadPriority;
        !           108: 
        !           109: /*
        !           110: ** Create a new thread:
        !           111: **     "type" is the type of thread to create
        !           112: **     "start(arg)" will be invoked as the threads "main"
        !           113: **     "priority" will be created thread's priority
        !           114: **     "scope" will specify whether the thread is local or global
        !           115: **     "state" will specify whether the thread is joinable or not
        !           116: **     "stackSize" the size of the stack, in bytes. The value can be zero
        !           117: **        and then a machine specific stack size will be chosen.
        !           118: **
        !           119: ** This can return NULL if some kind of error occurs, such as if memory is
        !           120: ** tight.
        !           121: **
        !           122: ** If you want the thread to start up waiting for the creator to do
        !           123: ** something, enter a lock before creating the thread and then have the
        !           124: ** threads start routine enter and exit the same lock. When you are ready
        !           125: ** for the thread to run, exit the lock.
        !           126: **
        !           127: ** If you want to detect the completion of the created thread, the thread
        !           128: ** should be created joinable.  Then, use PR_JoinThread to synchrnoize the
        !           129: ** termination of another thread.
        !           130: **
        !           131: ** When the start function returns the thread exits. If it is the last
        !           132: ** PR_USER_THREAD to exit then the process exits.
        !           133: */
        !           134: NSPR_API(PRThread*) PR_CreateThread(PRThreadType type,
        !           135:                      void (PR_CALLBACK *start)(void *arg),
        !           136:                      void *arg,
        !           137:                      PRThreadPriority priority,
        !           138:                      PRThreadScope scope,
        !           139:                      PRThreadState state,
        !           140:                      PRUint32 stackSize);
        !           141: 
        !           142: /*
        !           143: ** Wait for thread termination:
        !           144: **     "thread" is the target thread 
        !           145: **
        !           146: ** This can return PR_FAILURE if no joinable thread could be found 
        !           147: ** corresponding to the specified target thread.
        !           148: **
        !           149: ** The calling thread is blocked until the target thread completes.
        !           150: ** Several threads cannot wait for the same thread to complete; one thread
        !           151: ** will operate successfully and others will terminate with an error PR_FAILURE.
        !           152: ** The calling thread will not be blocked if the target thread has already
        !           153: ** terminated.
        !           154: */
        !           155: NSPR_API(PRStatus) PR_JoinThread(PRThread *thread);
        !           156: 
        !           157: /*
        !           158: ** Return the current thread object for the currently running code.
        !           159: ** Never returns NULL.
        !           160: */
        !           161: NSPR_API(PRThread*) PR_GetCurrentThread(void);
        !           162: #ifndef NO_NSPR_10_SUPPORT
        !           163: #define PR_CurrentThread() PR_GetCurrentThread() /* for nspr1.0 compat. */
        !           164: #endif /* NO_NSPR_10_SUPPORT */
        !           165: 
        !           166: /*
        !           167: ** Get the priority of "thread".
        !           168: */
        !           169: NSPR_API(PRThreadPriority) PR_GetThreadPriority(const PRThread *thread);
        !           170: 
        !           171: /*
        !           172: ** Change the priority of the "thread" to "priority".
        !           173: */
        !           174: NSPR_API(void) PR_SetThreadPriority(PRThread *thread, PRThreadPriority priority);
        !           175: 
        !           176: /*
        !           177: ** This routine returns a new index for per-thread-private data table. 
        !           178: ** The index is visible to all threads within a process. This index can 
        !           179: ** be used with the PR_SetThreadPrivate() and PR_GetThreadPrivate() routines 
        !           180: ** to save and retrieve data associated with the index for a thread.
        !           181: **
        !           182: ** Each index is associationed with a destructor function ('dtor'). The function
        !           183: ** may be specified as NULL when the index is created. If it is not NULL, the
        !           184: ** function will be called when:
        !           185: **      - the thread exits and the private data for the associated index
        !           186: **        is not NULL,
        !           187: **      - new thread private data is set and the current private data is
        !           188: **        not NULL.
        !           189: **
        !           190: ** The index independently maintains specific values for each binding thread. 
        !           191: ** A thread can only get access to its own thread-specific-data.
        !           192: **
        !           193: ** Upon a new index return the value associated with the index for all threads
        !           194: ** is NULL, and upon thread creation the value associated with all indices for 
        !           195: ** that thread is NULL. 
        !           196: **
        !           197: ** Returns PR_FAILURE if the total number of indices will exceed the maximun 
        !           198: ** allowed.
        !           199: */
        !           200: typedef void (PR_CALLBACK *PRThreadPrivateDTOR)(void *priv);
        !           201: 
        !           202: NSPR_API(PRStatus) PR_NewThreadPrivateIndex(
        !           203:     PRUintn *newIndex, PRThreadPrivateDTOR destructor);
        !           204: 
        !           205: /*
        !           206: ** Define some per-thread-private data.
        !           207: **     "tpdIndex" is an index into the per-thread private data table
        !           208: **     "priv" is the per-thread-private data 
        !           209: **
        !           210: ** If the per-thread private data table has a previously registered
        !           211: ** destructor function and a non-NULL per-thread-private data value,
        !           212: ** the destructor function is invoked.
        !           213: **
        !           214: ** This can return PR_FAILURE if the index is invalid.
        !           215: */
        !           216: NSPR_API(PRStatus) PR_SetThreadPrivate(PRUintn tpdIndex, void *priv);
        !           217: 
        !           218: /*
        !           219: ** Recover the per-thread-private data for the current thread. "tpdIndex" is
        !           220: ** the index into the per-thread private data table. 
        !           221: **
        !           222: ** The returned value may be NULL which is indistinguishable from an error 
        !           223: ** condition.
        !           224: **
        !           225: ** A thread can only get access to its own thread-specific-data.
        !           226: */
        !           227: NSPR_API(void*) PR_GetThreadPrivate(PRUintn tpdIndex);
        !           228: 
        !           229: /*
        !           230: ** This routine sets the interrupt request for a target thread. The interrupt
        !           231: ** request remains in the thread's state until it is delivered exactly once
        !           232: ** or explicitly canceled.
        !           233: **
        !           234: ** A thread that has been interrupted will fail all NSPR blocking operations
        !           235: ** that return a PRStatus (I/O, waiting on a condition, etc).
        !           236: **
        !           237: ** PR_Interrupt may itself fail if the target thread is invalid.
        !           238: */
        !           239: NSPR_API(PRStatus) PR_Interrupt(PRThread *thread);
        !           240: 
        !           241: /*
        !           242: ** Clear the interrupt request for the calling thread. If no such request
        !           243: ** is pending, this operation is a noop.
        !           244: */
        !           245: NSPR_API(void) PR_ClearInterrupt(void);
        !           246: 
        !           247: /*
        !           248: ** Block the interrupt for the calling thread.
        !           249: */
        !           250: NSPR_API(void) PR_BlockInterrupt(void);
        !           251: 
        !           252: /*
        !           253: ** Unblock the interrupt for the calling thread.
        !           254: */
        !           255: NSPR_API(void) PR_UnblockInterrupt(void);
        !           256: 
        !           257: /*
        !           258: ** Make the current thread sleep until "ticks" time amount of time
        !           259: ** has expired. If "ticks" is PR_INTERVAL_NO_WAIT then the call is
        !           260: ** equivalent to calling PR_Yield. Calling PR_Sleep with an argument
        !           261: ** equivalent to PR_INTERVAL_NO_TIMEOUT is an error and will result
        !           262: ** in a PR_FAILURE error return.
        !           263: */
        !           264: NSPR_API(PRStatus) PR_Sleep(PRIntervalTime ticks);
        !           265: 
        !           266: /*
        !           267: ** Get the scoping of this thread.
        !           268: */
        !           269: NSPR_API(PRThreadScope) PR_GetThreadScope(const PRThread *thread);
        !           270: 
        !           271: /*
        !           272: ** Get the type of this thread.
        !           273: */
        !           274: NSPR_API(PRThreadType) PR_GetThreadType(const PRThread *thread);
        !           275: 
        !           276: /*
        !           277: ** Get the join state of this thread.
        !           278: */
        !           279: NSPR_API(PRThreadState) PR_GetThreadState(const PRThread *thread);
        !           280: 
        !           281: PR_END_EXTERN_C
        !           282: 
        !           283: #endif /* prthread_h___ */

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