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Unified Diff: mozilla/nsprpub/pr/src/io/prfdcach.c

Issue 14249009: Change the NSS and NSPR source tree to the new directory structure to be (Closed) Base URL: svn://svn.chromium.org/chrome/trunk/deps/third_party/nss/
Patch Set: Created 7 years, 8 months ago
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Index: mozilla/nsprpub/pr/src/io/prfdcach.c
===================================================================
--- mozilla/nsprpub/pr/src/io/prfdcach.c (revision 191424)
+++ mozilla/nsprpub/pr/src/io/prfdcach.c (working copy)
@@ -1,292 +0,0 @@
-/* -*- 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/. */
-
-#include "primpl.h"
-
-#include <string.h>
-
-/*****************************************************************************/
-/*****************************************************************************/
-/************************** File descriptor caching **************************/
-/*****************************************************************************/
-/*****************************************************************************/
-
-/*
-** This code is built into debuggable versions of NSPR to assist in
-** finding misused file descriptors. Since file descritors (PRFileDesc)
-** are identified by a pointer to their structure, they can be the
-** target of dangling references. Furthermore, NSPR caches and tries
-** to aggressively reuse file descriptors, leading to more ambiguity.
-** The following code will allow a debugging client to set environment
-** variables and control the number of file descriptors that will be
-** preserved before they are recycled. The environment variables are
-** NSPR_FD_CACHE_SIZE_LOW and NSPR_FD_CACHE_SIZE_HIGH. The former sets
-** the number of descriptors NSPR will allocate before beginning to
-** recycle. The latter is the maximum number permitted in the cache
-** (exclusive of those in use) at a time.
-*/
-typedef struct _PR_Fd_Cache
-{
- PRLock *ml;
- PRIntn count;
- PRStack *stack;
- PRFileDesc *head, *tail;
- PRIntn limit_low, limit_high;
-} _PR_Fd_Cache;
-
-static _PR_Fd_Cache _pr_fd_cache;
-static PRFileDesc **stack2fd = &(((PRFileDesc*)NULL)->higher);
-
-
-/*
-** Get a FileDescriptor from the cache if one exists. If not allocate
-** a new one from the heap.
-*/
-PRFileDesc *_PR_Getfd(void)
-{
- PRFileDesc *fd;
- /*
- ** $$$
- ** This may look a little wasteful. We'll see. Right now I want to
- ** be able to toggle between caching and not at runtime to measure
- ** the differences. If it isn't too annoying, I'll leave it in.
- ** $$$$
- **
- ** The test is against _pr_fd_cache.limit_high. If that's zero,
- ** we're not doing the extended cache but going for performance.
- */
- if (0 == _pr_fd_cache.limit_high)
- {
- PRStackElem *pop;
- PR_ASSERT(NULL != _pr_fd_cache.stack);
- pop = PR_StackPop(_pr_fd_cache.stack);
- if (NULL == pop) goto allocate;
- fd = (PRFileDesc*)((PRPtrdiff)pop - (PRPtrdiff)stack2fd);
- }
- else
- {
- do
- {
- if (NULL == _pr_fd_cache.head) goto allocate; /* nothing there */
- if (_pr_fd_cache.count < _pr_fd_cache.limit_low) goto allocate;
-
- /* we "should" be able to extract an fd from the cache */
- PR_Lock(_pr_fd_cache.ml); /* need the lock to do this safely */
- fd = _pr_fd_cache.head; /* protected extraction */
- if (NULL == fd) /* unexpected, but not fatal */
- {
- PR_ASSERT(0 == _pr_fd_cache.count);
- PR_ASSERT(NULL == _pr_fd_cache.tail);
- }
- else
- {
- _pr_fd_cache.count -= 1;
- _pr_fd_cache.head = fd->higher;
- if (NULL == _pr_fd_cache.head)
- {
- PR_ASSERT(0 == _pr_fd_cache.count);
- _pr_fd_cache.tail = NULL;
- }
- PR_ASSERT(&_pr_faulty_methods == fd->methods);
- PR_ASSERT(PR_INVALID_IO_LAYER == fd->identity);
- PR_ASSERT(_PR_FILEDESC_FREED == fd->secret->state);
- }
- PR_Unlock(_pr_fd_cache.ml);
-
- } while (NULL == fd); /* then go around and allocate a new one */
- }
-
-finished:
- fd->dtor = NULL;
- fd->lower = fd->higher = NULL;
- fd->identity = PR_NSPR_IO_LAYER;
- memset(fd->secret, 0, sizeof(PRFilePrivate));
- return fd;
-
-allocate:
- fd = PR_NEW(PRFileDesc);
- if (NULL != fd)
- {
- fd->secret = PR_NEW(PRFilePrivate);
- if (NULL == fd->secret) PR_DELETE(fd);
- }
- if (NULL != fd) goto finished;
- else return NULL;
-
-} /* _PR_Getfd */
-
-/*
-** Return a file descriptor to the cache unless there are too many in
-** there already. If put in cache, clear the fields first.
-*/
-void _PR_Putfd(PRFileDesc *fd)
-{
- PR_ASSERT(PR_NSPR_IO_LAYER == fd->identity);
- fd->methods = &_pr_faulty_methods;
- fd->identity = PR_INVALID_IO_LAYER;
- fd->secret->state = _PR_FILEDESC_FREED;
-
- if (0 == _pr_fd_cache.limit_high)
- {
- PR_StackPush(_pr_fd_cache.stack, (PRStackElem*)(&fd->higher));
- }
- else
- {
- if (_pr_fd_cache.count > _pr_fd_cache.limit_high)
- {
- PR_Free(fd->secret);
- PR_Free(fd);
- }
- else
- {
- PR_Lock(_pr_fd_cache.ml);
- if (NULL == _pr_fd_cache.tail)
- {
- PR_ASSERT(0 == _pr_fd_cache.count);
- PR_ASSERT(NULL == _pr_fd_cache.head);
- _pr_fd_cache.head = _pr_fd_cache.tail = fd;
- }
- else
- {
- PR_ASSERT(NULL == _pr_fd_cache.tail->higher);
- _pr_fd_cache.tail->higher = fd;
- _pr_fd_cache.tail = fd; /* new value */
- }
- fd->higher = NULL; /* always so */
- _pr_fd_cache.count += 1; /* count the new entry */
- PR_Unlock(_pr_fd_cache.ml);
- }
- }
-} /* _PR_Putfd */
-
-PR_IMPLEMENT(PRStatus) PR_SetFDCacheSize(PRIntn low, PRIntn high)
-{
- /*
- ** This can be called at any time, may adjust the cache sizes,
- ** turn the caches off, or turn them on. It is not dependent
- ** on the compilation setting of DEBUG.
- */
- if (!_pr_initialized) _PR_ImplicitInitialization();
-
- if (low > high) low = high; /* sanity check the params */
-
- PR_Lock(_pr_fd_cache.ml);
- if (0 == high) /* shutting down or staying down */
- {
- if (0 != _pr_fd_cache.limit_high) /* shutting down */
- {
- _pr_fd_cache.limit_high = 0; /* stop use */
- /*
- ** Hold the lock throughout - nobody's going to want it
- ** other than another caller to this routine. Just don't
- ** let that happen.
- **
- ** Put all the cached fds onto the new cache.
- */
- while (NULL != _pr_fd_cache.head)
- {
- PRFileDesc *fd = _pr_fd_cache.head;
- _pr_fd_cache.head = fd->higher;
- PR_StackPush(_pr_fd_cache.stack, (PRStackElem*)(&fd->higher));
- }
- _pr_fd_cache.limit_low = 0;
- _pr_fd_cache.tail = NULL;
- _pr_fd_cache.count = 0;
- }
- }
- else /* starting up or just adjusting parameters */
- {
- PRBool was_using_stack = (0 == _pr_fd_cache.limit_high);
- _pr_fd_cache.limit_low = low;
- _pr_fd_cache.limit_high = high;
- if (was_using_stack) /* was using stack - feed into cache */
- {
- PRStackElem *pop;
- while (NULL != (pop = PR_StackPop(_pr_fd_cache.stack)))
- {
- PRFileDesc *fd = (PRFileDesc*)
- ((PRPtrdiff)pop - (PRPtrdiff)stack2fd);
- if (NULL == _pr_fd_cache.tail) _pr_fd_cache.tail = fd;
- fd->higher = _pr_fd_cache.head;
- _pr_fd_cache.head = fd;
- _pr_fd_cache.count += 1;
- }
- }
- }
- PR_Unlock(_pr_fd_cache.ml);
- return PR_SUCCESS;
-} /* PR_SetFDCacheSize */
-
-void _PR_InitFdCache(void)
-{
- /*
- ** The fd caching is enabled by default for DEBUG builds,
- ** disabled by default for OPT builds. That default can
- ** be overridden at runtime using environment variables
- ** or a super-wiz-bang API.
- */
- const char *low = PR_GetEnv("NSPR_FD_CACHE_SIZE_LOW");
- const char *high = PR_GetEnv("NSPR_FD_CACHE_SIZE_HIGH");
-
- /*
- ** _low is allowed to be zero, _high is not.
- ** If _high is zero, we're not doing the caching.
- */
-
- _pr_fd_cache.limit_low = 0;
-#if defined(DEBUG)
- _pr_fd_cache.limit_high = FD_SETSIZE;
-#else
- _pr_fd_cache.limit_high = 0;
-#endif /* defined(DEBUG) */
-
- if (NULL != low) _pr_fd_cache.limit_low = atoi(low);
- if (NULL != high) _pr_fd_cache.limit_high = atoi(high);
-
- if (_pr_fd_cache.limit_low < 0)
- _pr_fd_cache.limit_low = 0;
- if (_pr_fd_cache.limit_low > FD_SETSIZE)
- _pr_fd_cache.limit_low = FD_SETSIZE;
-
- if (_pr_fd_cache.limit_high > FD_SETSIZE)
- _pr_fd_cache.limit_high = FD_SETSIZE;
-
- if (_pr_fd_cache.limit_high < _pr_fd_cache.limit_low)
- _pr_fd_cache.limit_high = _pr_fd_cache.limit_low;
-
- _pr_fd_cache.ml = PR_NewLock();
- PR_ASSERT(NULL != _pr_fd_cache.ml);
- _pr_fd_cache.stack = PR_CreateStack("FD");
- PR_ASSERT(NULL != _pr_fd_cache.stack);
-
-} /* _PR_InitFdCache */
-
-void _PR_CleanupFdCache(void)
-{
- PRFileDesc *fd, *next;
- PRStackElem *pop;
-
- for (fd = _pr_fd_cache.head; fd != NULL; fd = next)
- {
- next = fd->higher;
- PR_DELETE(fd->secret);
- PR_DELETE(fd);
- }
- _pr_fd_cache.head = NULL;
- _pr_fd_cache.tail = NULL;
- _pr_fd_cache.count = 0;
- PR_DestroyLock(_pr_fd_cache.ml);
- _pr_fd_cache.ml = NULL;
- while ((pop = PR_StackPop(_pr_fd_cache.stack)) != NULL)
- {
- fd = (PRFileDesc*)((PRPtrdiff)pop - (PRPtrdiff)stack2fd);
- PR_DELETE(fd->secret);
- PR_DELETE(fd);
- }
- PR_DestroyStack(_pr_fd_cache.stack);
- _pr_fd_cache.stack = NULL;
-} /* _PR_CleanupFdCache */
-
-/* prfdcach.c */
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