Mercurial > trustbridge > nss-cmake-static
view nspr/pr/include/prthread.h @ 3:150b72113545
Add DBM and legacydb support
author | Andre Heinecke <andre.heinecke@intevation.de> |
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date | Tue, 05 Aug 2014 18:32:02 +0200 |
parents | 1e5118fa0cb1 |
children |
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/* -*- 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/. */ #ifndef prthread_h___ #define prthread_h___ /* ** API for NSPR threads. On some architectures (Mac OS Classic ** notably) pre-emptibility is not guaranteed. Hard priority scheduling ** is not guaranteed, so programming using priority based synchronization ** is a no-no. ** ** NSPR threads are scheduled based loosely on their client set priority. ** In general, a thread of a higher priority has a statistically better ** chance of running relative to threads of lower priority. However, ** NSPR uses multiple strategies to provide execution vehicles for thread ** abstraction of various host platforms. As it turns out, there is little ** NSPR can do to affect the scheduling attributes of "GLOBAL" threads. ** However, a semblance of GLOBAL threads is used to implement "LOCAL" ** threads. An arbitrary number of such LOCAL threads can be assigned to ** a single GLOBAL thread. ** ** For scheduling, NSPR will attempt to run the highest priority LOCAL ** thread associated with a given GLOBAL thread. It is further assumed ** that the host OS will apply some form of "fair" scheduling on the ** GLOBAL threads. ** ** Threads have a "system flag" which when set indicates the thread ** doesn't count for determining when the process should exit (the ** process exits when the last user thread exits). ** ** Threads also have a "scope flag" which controls whether the threads ** are scheduled in the local scope or scheduled by the OS globally. This ** indicates whether a thread is permanently bound to a native OS thread. ** An unbound thread competes for scheduling resources in the same process. ** ** Another flag is "state flag" which control whether the thread is joinable. ** It allows other threads to wait for the created thread to reach completion. ** ** Threads can have "per-thread-data" attached to them. Each thread has a ** per-thread error number and error string which are updated when NSPR ** operations fail. */ #include "prtypes.h" #include "prinrval.h" PR_BEGIN_EXTERN_C typedef struct PRThread PRThread; typedef struct PRThreadStack PRThreadStack; typedef enum PRThreadType { PR_USER_THREAD, PR_SYSTEM_THREAD } PRThreadType; typedef enum PRThreadScope { PR_LOCAL_THREAD, PR_GLOBAL_THREAD, PR_GLOBAL_BOUND_THREAD } PRThreadScope; typedef enum PRThreadState { PR_JOINABLE_THREAD, PR_UNJOINABLE_THREAD } PRThreadState; typedef enum PRThreadPriority { PR_PRIORITY_FIRST = 0, /* just a placeholder */ PR_PRIORITY_LOW = 0, /* the lowest possible priority */ PR_PRIORITY_NORMAL = 1, /* most common expected priority */ PR_PRIORITY_HIGH = 2, /* slightly more aggressive scheduling */ PR_PRIORITY_URGENT = 3, /* it does little good to have more than one */ PR_PRIORITY_LAST = 3 /* this is just a placeholder */ } PRThreadPriority; /* ** Create a new thread: ** "type" is the type of thread to create ** "start(arg)" will be invoked as the threads "main" ** "priority" will be created thread's priority ** "scope" will specify whether the thread is local or global ** "state" will specify whether the thread is joinable or not ** "stackSize" the size of the stack, in bytes. The value can be zero ** and then a machine specific stack size will be chosen. ** ** This can return NULL if some kind of error occurs, such as if memory is ** tight. ** ** If you want the thread to start up waiting for the creator to do ** something, enter a lock before creating the thread and then have the ** threads start routine enter and exit the same lock. When you are ready ** for the thread to run, exit the lock. ** ** If you want to detect the completion of the created thread, the thread ** should be created joinable. Then, use PR_JoinThread to synchrnoize the ** termination of another thread. ** ** When the start function returns the thread exits. If it is the last ** PR_USER_THREAD to exit then the process exits. */ NSPR_API(PRThread*) PR_CreateThread(PRThreadType type, void (PR_CALLBACK *start)(void *arg), void *arg, PRThreadPriority priority, PRThreadScope scope, PRThreadState state, PRUint32 stackSize); /* ** Wait for thread termination: ** "thread" is the target thread ** ** This can return PR_FAILURE if no joinable thread could be found ** corresponding to the specified target thread. ** ** The calling thread is blocked until the target thread completes. ** Several threads cannot wait for the same thread to complete; one thread ** will operate successfully and others will terminate with an error PR_FAILURE. ** The calling thread will not be blocked if the target thread has already ** terminated. */ NSPR_API(PRStatus) PR_JoinThread(PRThread *thread); /* ** Return the current thread object for the currently running code. ** Never returns NULL. */ NSPR_API(PRThread*) PR_GetCurrentThread(void); #ifndef NO_NSPR_10_SUPPORT #define PR_CurrentThread() PR_GetCurrentThread() /* for nspr1.0 compat. */ #endif /* NO_NSPR_10_SUPPORT */ /* ** Get the priority of "thread". */ NSPR_API(PRThreadPriority) PR_GetThreadPriority(const PRThread *thread); /* ** Change the priority of the "thread" to "priority". ** ** PR_SetThreadPriority works in a best-effort manner. On some platforms a ** special privilege, such as root access, is required to change thread ** priorities, especially to raise thread priorities. If the caller doesn't ** have enough privileges to change thread priorites, the function has no ** effect except causing a future PR_GetThreadPriority call to return ** |priority|. */ NSPR_API(void) PR_SetThreadPriority(PRThread *thread, PRThreadPriority priority); /* ** Set the name of the current thread, which will be visible in a debugger ** and accessible via a call to PR_GetThreadName(). */ NSPR_API(PRStatus) PR_SetCurrentThreadName(const char *name); /* ** Return the name of "thread", if set. Otherwise return NULL. */ NSPR_API(const char *) PR_GetThreadName(const PRThread *thread); /* ** This routine returns a new index for per-thread-private data table. ** The index is visible to all threads within a process. This index can ** be used with the PR_SetThreadPrivate() and PR_GetThreadPrivate() routines ** to save and retrieve data associated with the index for a thread. ** ** Each index is associationed with a destructor function ('dtor'). The function ** may be specified as NULL when the index is created. If it is not NULL, the ** function will be called when: ** - the thread exits and the private data for the associated index ** is not NULL, ** - new thread private data is set and the current private data is ** not NULL. ** ** The index independently maintains specific values for each binding thread. ** A thread can only get access to its own thread-specific-data. ** ** Upon a new index return the value associated with the index for all threads ** is NULL, and upon thread creation the value associated with all indices for ** that thread is NULL. ** ** Returns PR_FAILURE if the total number of indices will exceed the maximun ** allowed. */ typedef void (PR_CALLBACK *PRThreadPrivateDTOR)(void *priv); NSPR_API(PRStatus) PR_NewThreadPrivateIndex( PRUintn *newIndex, PRThreadPrivateDTOR destructor); /* ** Define some per-thread-private data. ** "tpdIndex" is an index into the per-thread private data table ** "priv" is the per-thread-private data ** ** If the per-thread private data table has a previously registered ** destructor function and a non-NULL per-thread-private data value, ** the destructor function is invoked. ** ** This can return PR_FAILURE if the index is invalid. */ NSPR_API(PRStatus) PR_SetThreadPrivate(PRUintn tpdIndex, void *priv); /* ** Recover the per-thread-private data for the current thread. "tpdIndex" is ** the index into the per-thread private data table. ** ** The returned value may be NULL which is indistinguishable from an error ** condition. ** ** A thread can only get access to its own thread-specific-data. */ NSPR_API(void*) PR_GetThreadPrivate(PRUintn tpdIndex); /* ** This routine sets the interrupt request for a target thread. The interrupt ** request remains in the thread's state until it is delivered exactly once ** or explicitly canceled. ** ** A thread that has been interrupted will fail all NSPR blocking operations ** that return a PRStatus (I/O, waiting on a condition, etc). ** ** PR_Interrupt may itself fail if the target thread is invalid. */ NSPR_API(PRStatus) PR_Interrupt(PRThread *thread); /* ** Clear the interrupt request for the calling thread. If no such request ** is pending, this operation is a noop. */ NSPR_API(void) PR_ClearInterrupt(void); /* ** Block the interrupt for the calling thread. */ NSPR_API(void) PR_BlockInterrupt(void); /* ** Unblock the interrupt for the calling thread. */ NSPR_API(void) PR_UnblockInterrupt(void); /* ** Make the current thread sleep until "ticks" time amount of time ** has expired. If "ticks" is PR_INTERVAL_NO_WAIT then the call is ** equivalent to calling PR_Yield. Calling PR_Sleep with an argument ** equivalent to PR_INTERVAL_NO_TIMEOUT is an error and will result ** in a PR_FAILURE error return. */ NSPR_API(PRStatus) PR_Sleep(PRIntervalTime ticks); /* ** Get the scoping of this thread. */ NSPR_API(PRThreadScope) PR_GetThreadScope(const PRThread *thread); /* ** Get the type of this thread. */ NSPR_API(PRThreadType) PR_GetThreadType(const PRThread *thread); /* ** Get the join state of this thread. */ NSPR_API(PRThreadState) PR_GetThreadState(const PRThread *thread); PR_END_EXTERN_C #endif /* prthread_h___ */