The Tor Browser: comparison nsprpub/pr/src/threads/prtpd.c

--1:000000000000
+:d59b77c079c2
+/* -*- 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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comparison: nsprpub/pr/src/threads/prtpd.c

nsprpub/pr/src/threads/prtpd.c