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 */ |