The Tor Browser: nsprpub/pr/src/threads/prtpd.c@6474c204b198 (annotated)

nsprpub/pr/src/threads/prtpd.c@6474c204b198 (annotated)

nsprpub/pr/src/threads/prtpd.c

Wed, 31 Dec 2014 06:09:35 +0100

author: Michael Schloh von Bennewitz <michael@schloh.com>
date: Wed, 31 Dec 2014 06:09:35 +0100
changeset 0: 6474c204b198
permissions: -rw-r--r--

Cloned upstream origin tor-browser at tor-browser-31.3.0esr-4.5-1-build1
revision ID fc1c9ff7c1b2defdbc039f12214767608f46423f for hacking purpose.

 /* -*- 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/. */
 /*
 ** Thread Private Data
 **
 ** There is an aribitrary limit on the number of keys that will be allocated
 ** by the runtime. It's largish, so it is intended to be a sanity check, not
 ** an impediment.
 **
 ** There is a counter, initialized to zero and incremented every time a
 ** client asks for a new key, that holds the high water mark for keys. All
 ** threads logically have the same high water mark and are permitted to
 ** ask for TPD up to that key value.
 **
 ** The vector to hold the TPD are allocated when PR_SetThreadPrivate() is
 ** called. The size of the vector will be some value greater than or equal
 ** to the current high water mark. Each thread has its own TPD length and
 ** vector.
 **
 ** Threads that get private data for keys they have not set (or perhaps
 ** don't even exist for that thread) get a NULL return. If the key is
 ** beyond the high water mark, an error will be returned.
 */
 /*
 ** As of this time, BeOS has its own TPD implementation.  Integrating
 ** this standard one is a TODO for anyone with a bit of spare time on
 ** their hand.  For now, we just #ifdef out this whole file and use
 ** the routines in pr/src/btthreads/
 */
 #ifndef XP_BEOS
 #include "primpl.h"
 #include <string.h>
 #if defined(WIN95)
 /*
 ** Some local variables report warnings on Win95 because the code paths
 ** using them are conditioned on HAVE_CUSTOME_USER_THREADS.
 ** The pragma suppresses the warning.
 **
 */
 #pragma warning(disable : 4101)
 #endif
 #define _PR_TPD_LIMIT 128               /* arbitary limit on the TPD slots */
 static PRInt32 _pr_tpd_length = 0;      /* current length of destructor vector */
 static PRInt32 _pr_tpd_highwater = 0;   /* next TPD key to be assigned */
 static PRThreadPrivateDTOR *_pr_tpd_destructors = NULL;
                                         /* the destructors are associated with
                                             the keys, therefore asserting that
                                             the TPD key depicts the data's 'type' */
 /*
 ** Initialize the thread private data manipulation
 */
 void _PR_InitTPD(void)
 {
     _pr_tpd_destructors = (PRThreadPrivateDTOR*)
         PR_CALLOC(_PR_TPD_LIMIT * sizeof(PRThreadPrivateDTOR*));
     PR_ASSERT(NULL != _pr_tpd_destructors);
     _pr_tpd_length = _PR_TPD_LIMIT;
 }
 /*
 ** Clean up the thread private data manipulation
 */
 void _PR_CleanupTPD(void)
 {
 }  /* _PR_CleanupTPD */
 /*
 ** 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.
 **
 ** 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.
 **
 **     "dtor" is the destructor function to invoke when the private
 **       data is set or destroyed
 **
 ** Returns PR_FAILURE if the total number of indices will exceed the maximun
 ** allowed.
 */
 PR_IMPLEMENT(PRStatus) PR_NewThreadPrivateIndex(
     PRUintn *newIndex, PRThreadPrivateDTOR dtor)
 {
     PRStatus rv;
     PRInt32 index;
     if (!_pr_initialized) _PR_ImplicitInitialization();
     PR_ASSERT(NULL != newIndex);
     PR_ASSERT(NULL != _pr_tpd_destructors);
     index = PR_ATOMIC_INCREMENT(&_pr_tpd_highwater) - 1;  /* allocate index */
     if (_PR_TPD_LIMIT <= index)
     {
         PR_SetError(PR_TPD_RANGE_ERROR, 0);
         rv = PR_FAILURE;  /* that's just wrong */
     }
     else
     {
         _pr_tpd_destructors[index] = dtor;  /* record destructor @index */
         *newIndex = (PRUintn)index;  /* copy into client's location */
         rv = PR_SUCCESS;  /* that's okay */
     }
     return rv;
 }
 /*
 ** Define some per-thread-private data.
 **     "index" 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 index is invalid (ie., beyond the current
 ** high water mark) or memory is insufficient to allocate an exanded vector.
 */
 PR_IMPLEMENT(PRStatus) PR_SetThreadPrivate(PRUintn index, void *priv)
 {
     PRThread *self = PR_GetCurrentThread();
     /*
     ** The index being set might not have a sufficient vector in this
     ** thread. But if the index has been allocated, it's okay to go
     ** ahead and extend this one now.
     */
     if ((index >= _PR_TPD_LIMIT) || (index >= _pr_tpd_highwater))
     {
         PR_SetError(PR_TPD_RANGE_ERROR, 0);
         return PR_FAILURE;
     }
     PR_ASSERT(((NULL == self->privateData) && (0 == self->tpdLength))
         || ((NULL != self->privateData) && (0 != self->tpdLength)));
     if ((NULL == self->privateData) || (self->tpdLength <= index))
     {
         void *extension = PR_CALLOC(_pr_tpd_length * sizeof(void*));
         if (NULL == extension)
         {
             PR_SetError(PR_OUT_OF_MEMORY_ERROR, 0);
             return PR_FAILURE;
         }
         if (self->privateData) {
             (void)memcpy(
                 extension, self->privateData,
                 self->tpdLength * sizeof(void*));
             PR_DELETE(self->privateData);
         }
         self->tpdLength = _pr_tpd_length;
         self->privateData = (void**)extension;
     }
     /*
     ** There wasn't much chance of having to call the destructor
     ** unless the slot already existed.
     */
     else if (self->privateData[index] && _pr_tpd_destructors[index])
     {
         void *data = self->privateData[index];
         self->privateData[index] = NULL;
         (*_pr_tpd_destructors[index])(data);
     }
     PR_ASSERT(index < self->tpdLength);
     self->privateData[index] = priv;
     return PR_SUCCESS;
 }
 /*
 ** Recover the per-thread-private data for the current thread. "index" is
 ** the index into the per-thread private data table.
 **
 ** The returned value may be NULL which is indistinguishable from an error
 ** condition.
 **
 */
 PR_IMPLEMENT(void*) PR_GetThreadPrivate(PRUintn index)
 {
     PRThread *self = PR_GetCurrentThread();
     void *tpd = ((NULL == self->privateData) || (index >= self->tpdLength)) ?
         NULL : self->privateData[index];
     return tpd;
 }
 /*
 ** Destroy the thread's private data, if any exists. This is called at
 ** thread termination time only. There should be no threading issues
 ** since this is being called by the thread itself.
 */
 void _PR_DestroyThreadPrivate(PRThread* self)
 {
 #define _PR_TPD_DESTRUCTOR_ITERATIONS 4
     if (NULL != self->privateData)  /* we have some */
     {
         PRBool clean;
         PRUint32 index;
         PRInt32 passes = _PR_TPD_DESTRUCTOR_ITERATIONS;
         PR_ASSERT(0 != self->tpdLength);
         do
         {
             clean = PR_TRUE;
             for (index = 0; index < self->tpdLength; ++index)
             {
                 void *priv = self->privateData[index];  /* extract */
                 if (NULL != priv)  /* we have data at this index */
                 {
                     if (NULL != _pr_tpd_destructors[index])
                     {
                         self->privateData[index] = NULL;  /* precondition */
                         (*_pr_tpd_destructors[index])(priv);  /* destroy */
                         clean = PR_FALSE;  /* unknown side effects */
                     }
                 }
             }
         } while ((--passes > 0) && !clean);  /* limit # of passes */
         /*
         ** We give up after a fixed number of passes. Any non-NULL
         ** thread-private data value with a registered destructor
         ** function is not destroyed.
         */
         memset(self->privateData, 0, self->tpdLength * sizeof(void*));
     }
 }  /* _PR_DestroyThreadPrivate */
 #endif /* !XP_BEOS */

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nsprpub/pr/src/threads/prtpd.c@6474c204b198 (annotated)

nsprpub/pr/src/threads/prtpd.c