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Diffstat (limited to 'rubbos/app/httpd-2.0.64/server/util_time.c')
| -rw-r--r-- | rubbos/app/httpd-2.0.64/server/util_time.c | 240 |
1 files changed, 0 insertions, 240 deletions
diff --git a/rubbos/app/httpd-2.0.64/server/util_time.c b/rubbos/app/httpd-2.0.64/server/util_time.c deleted file mode 100644 index e5a488ef..00000000 --- a/rubbos/app/httpd-2.0.64/server/util_time.c +++ /dev/null @@ -1,240 +0,0 @@ -/* Licensed to the Apache Software Foundation (ASF) under one or more - * contributor license agreements. See the NOTICE file distributed with - * this work for additional information regarding copyright ownership. - * The ASF licenses this file to You under the Apache License, Version 2.0 - * (the "License"); you may not use this file except in compliance with - * the License. You may obtain a copy of the License at - * - * http://www.apache.org/licenses/LICENSE-2.0 - * - * Unless required by applicable law or agreed to in writing, software - * distributed under the License is distributed on an "AS IS" BASIS, - * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. - * See the License for the specific language governing permissions and - * limitations under the License. - */ - -#include "util_time.h" - -/* Cache for exploded values of recent timestamps - */ - -struct exploded_time_cache_element { - apr_int64_t t; - apr_time_exp_t xt; - apr_int64_t t_validate; /* please see comments in cached_explode() */ -}; - -/* the "+ 1" is for the current second: */ -#define TIME_CACHE_SIZE (AP_TIME_RECENT_THRESHOLD + 1) - -/* Note that AP_TIME_RECENT_THRESHOLD is defined to - * be a power of two minus one in util_time.h, so that - * we can replace a modulo operation with a bitwise AND - * when hashing items into a cache of size - * AP_TIME_RECENT_THRESHOLD+1 - */ -#define TIME_CACHE_MASK (AP_TIME_RECENT_THRESHOLD) - -static struct exploded_time_cache_element exploded_cache_localtime[TIME_CACHE_SIZE]; -static struct exploded_time_cache_element exploded_cache_gmt[TIME_CACHE_SIZE]; - - -static apr_status_t cached_explode(apr_time_exp_t *xt, apr_time_t t, - struct exploded_time_cache_element *cache, - int use_gmt) -{ - apr_int64_t seconds = apr_time_sec(t); - struct exploded_time_cache_element *cache_element = - &(cache[seconds & TIME_CACHE_MASK]); - struct exploded_time_cache_element cache_element_snapshot; - - /* The cache is implemented as a ring buffer. Each second, - * it uses a different element in the buffer. The timestamp - * in the element indicates whether the element contains the - * exploded time for the current second (vs the time - * 'now - AP_TIME_RECENT_THRESHOLD' seconds ago). If the - * cached value is for the current time, we use it. Otherwise, - * we compute the apr_time_exp_t and store it in this - * cache element. Note that the timestamp in the cache - * element is updated only after the exploded time. Thus - * if two threads hit this cache element simultaneously - * at the start of a new second, they'll both explode the - * time and store it. I.e., the writers will collide, but - * they'll be writing the same value. - */ - if (cache_element->t >= seconds) { - /* There is an intentional race condition in this design: - * in a multithreaded app, one thread might be reading - * from this cache_element to resolve a timestamp from - * TIME_CACHE_SIZE seconds ago at the same time that - * another thread is copying the exploded form of the - * current time into the same cache_element. (I.e., the - * first thread might hit this element of the ring buffer - * just as the element is being recycled.) This can - * also happen at the start of a new second, if a - * reader accesses the cache_element after a writer - * has updated cache_element.t but before the writer - * has finished updating the whole cache_element. - * - * Rather than trying to prevent this race condition - * with locks, we allow it to happen and then detect - * and correct it. The detection works like this: - * Step 1: Take a "snapshot" of the cache element by - * copying it into a temporary buffer. - * Step 2: Check whether the snapshot contains consistent - * data: the timestamps at the start and end of - * the cache_element should both match the 'seconds' - * value that we computed from the input time. - * If these three don't match, then the snapshot - * shows the cache_element in the middle of an - * update, and its contents are invalid. - * Step 3: If the snapshot is valid, use it. Otherwise, - * just give up on the cache and explode the - * input time. - */ - memcpy(&cache_element_snapshot, cache_element, - sizeof(struct exploded_time_cache_element)); - if ((seconds != cache_element_snapshot.t) || - (seconds != cache_element_snapshot.t_validate)) { - /* Invalid snapshot */ - if (use_gmt) { - return apr_time_exp_gmt(xt, t); - } - else { - return apr_time_exp_lt(xt, t); - } - } - else { - /* Valid snapshot */ - memcpy(xt, &(cache_element_snapshot.xt), - sizeof(apr_time_exp_t)); - } - } - else { - apr_status_t r; - if (use_gmt) { - r = apr_time_exp_gmt(xt, t); - } - else { - r = apr_time_exp_lt(xt, t); - } - if (!APR_STATUS_IS_SUCCESS(r)) { - return r; - } - cache_element->t = seconds; - memcpy(&(cache_element->xt), xt, sizeof(apr_time_exp_t)); - cache_element->t_validate = seconds; - } - xt->tm_usec = (int)apr_time_usec(t); - return APR_SUCCESS; -} - - -AP_DECLARE(apr_status_t) ap_explode_recent_localtime(apr_time_exp_t * tm, - apr_time_t t) -{ - return cached_explode(tm, t, exploded_cache_localtime, 0); -} - -AP_DECLARE(apr_status_t) ap_explode_recent_gmt(apr_time_exp_t * tm, - apr_time_t t) -{ - return cached_explode(tm, t, exploded_cache_gmt, 1); -} - -AP_DECLARE(apr_status_t) ap_recent_ctime(char *date_str, apr_time_t t) -{ - /* ### This code is a clone of apr_ctime(), except that it - * uses ap_explode_recent_localtime() instead of apr_time_exp_lt(). - */ - apr_time_exp_t xt; - const char *s; - int real_year; - - /* example: "Wed Jun 30 21:49:08 1993" */ - /* 123456789012345678901234 */ - - ap_explode_recent_localtime(&xt, t); - s = &apr_day_snames[xt.tm_wday][0]; - *date_str++ = *s++; - *date_str++ = *s++; - *date_str++ = *s++; - *date_str++ = ' '; - s = &apr_month_snames[xt.tm_mon][0]; - *date_str++ = *s++; - *date_str++ = *s++; - *date_str++ = *s++; - *date_str++ = ' '; - *date_str++ = xt.tm_mday / 10 + '0'; - *date_str++ = xt.tm_mday % 10 + '0'; - *date_str++ = ' '; - *date_str++ = xt.tm_hour / 10 + '0'; - *date_str++ = xt.tm_hour % 10 + '0'; - *date_str++ = ':'; - *date_str++ = xt.tm_min / 10 + '0'; - *date_str++ = xt.tm_min % 10 + '0'; - *date_str++ = ':'; - *date_str++ = xt.tm_sec / 10 + '0'; - *date_str++ = xt.tm_sec % 10 + '0'; - *date_str++ = ' '; - real_year = 1900 + xt.tm_year; - *date_str++ = real_year / 1000 + '0'; - *date_str++ = real_year % 1000 / 100 + '0'; - *date_str++ = real_year % 100 / 10 + '0'; - *date_str++ = real_year % 10 + '0'; - *date_str++ = 0; - - return APR_SUCCESS; -} - -AP_DECLARE(apr_status_t) ap_recent_rfc822_date(char *date_str, apr_time_t t) -{ - /* ### This code is a clone of apr_rfc822_date(), except that it - * uses ap_explode_recent_gmt() instead of apr_time_exp_gmt(). - */ - apr_time_exp_t xt; - const char *s; - int real_year; - - ap_explode_recent_gmt(&xt, t); - - /* example: "Sat, 08 Jan 2000 18:31:41 GMT" */ - /* 12345678901234567890123456789 */ - - s = &apr_day_snames[xt.tm_wday][0]; - *date_str++ = *s++; - *date_str++ = *s++; - *date_str++ = *s++; - *date_str++ = ','; - *date_str++ = ' '; - *date_str++ = xt.tm_mday / 10 + '0'; - *date_str++ = xt.tm_mday % 10 + '0'; - *date_str++ = ' '; - s = &apr_month_snames[xt.tm_mon][0]; - *date_str++ = *s++; - *date_str++ = *s++; - *date_str++ = *s++; - *date_str++ = ' '; - real_year = 1900 + xt.tm_year; - /* This routine isn't y10k ready. */ - *date_str++ = real_year / 1000 + '0'; - *date_str++ = real_year % 1000 / 100 + '0'; - *date_str++ = real_year % 100 / 10 + '0'; - *date_str++ = real_year % 10 + '0'; - *date_str++ = ' '; - *date_str++ = xt.tm_hour / 10 + '0'; - *date_str++ = xt.tm_hour % 10 + '0'; - *date_str++ = ':'; - *date_str++ = xt.tm_min / 10 + '0'; - *date_str++ = xt.tm_min % 10 + '0'; - *date_str++ = ':'; - *date_str++ = xt.tm_sec / 10 + '0'; - *date_str++ = xt.tm_sec % 10 + '0'; - *date_str++ = ' '; - *date_str++ = 'G'; - *date_str++ = 'M'; - *date_str++ = 'T'; - *date_str++ = 0; - return APR_SUCCESS; -} |