From 30576c592b538cab293cf6e1f6265d376cd5a12c Mon Sep 17 00:00:00 2001
From: Andreas Gustafsson <source@isc.org>
Date: Thu, 13 Jul 2000 00:19:02 +0000
Subject: [PATCH]  330.   [func]          New function isc_log_wouldlog().

---
 CHANGES                   |  2 ++
 lib/isc/include/isc/log.h | 13 ++++++++++-
 lib/isc/log.c             | 45 ++++++++++++++++++++++-----------------
 3 files changed, 40 insertions(+), 20 deletions(-)

diff --git a/CHANGES b/CHANGES
index 0772b30444..c2421bde6c 100644
--- a/CHANGES
+++ b/CHANGES
@@ -1,3 +1,5 @@
+ 330.	[func]		New function isc_log_wouldlog().
+
  329.	[func]		omapi_auth_register() now takes a size_t argument for
 			the length of a key's secret data.  Previously
 			OMAPI only stored secrets up to the first NUL byte.
diff --git a/lib/isc/include/isc/log.h b/lib/isc/include/isc/log.h
index 091c763371..f80f735d59 100644
--- a/lib/isc/include/isc/log.h
+++ b/lib/isc/include/isc/log.h
@@ -15,7 +15,7 @@
  * SOFTWARE.
  */
 
-/* $Id: log.h,v 1.25 2000/06/19 21:45:03 explorer Exp $ */
+/* $Id: log.h,v 1.26 2000/07/13 00:18:53 gson Exp $ */
 
 #ifndef ISC_LOG_H
 #define ISC_LOG_H 1
@@ -627,6 +627,17 @@ isc_log_getdebuglevel(isc_log_t *lctx);
  *	The current logging debugging level is returned.
  */
 
+isc_boolean_t
+isc_log_wouldlog(isc_log_t *lctx, int level);
+/*
+ * Determine whether logging something to 'lctx' at 'level' would
+ * actually cause something to be logged somewhere.
+ *
+ * If ISC_FALSE is returned, it is guaranteed that nothing would
+ * be logged, allowing the caller to omit unnecessary
+ * isc_log_write() calls and possible message preformatting.
+ */
+
 void
 isc_log_setduplicateinterval(isc_logconfig_t *lcfg, unsigned int interval);
 /*
diff --git a/lib/isc/log.c b/lib/isc/log.c
index 93df1fe816..e3c5d308bc 100644
--- a/lib/isc/log.c
+++ b/lib/isc/log.c
@@ -15,7 +15,7 @@
  * SOFTWARE.
  */
 
-/* $Id: log.c,v 1.38 2000/06/23 17:52:20 tale Exp $ */
+/* $Id: log.c,v 1.39 2000/07/13 00:18:51 gson Exp $ */
 
 /* Principal Authors: DCL */
 
@@ -1197,6 +1197,30 @@ isc_log_open(isc_logchannel_t *channel) {
 	return (ISC_R_SUCCESS);
 }
 
+isc_boolean_t
+isc_log_wouldlog(isc_log_t *lctx, int level) {
+	/*
+	 * Try to avoid locking the mutex for messages which can't
+	 * possibly be logged to any channels -- primarily debugging
+	 * messages that the debug level is not high enough to print.
+	 *
+	 * If the level is (mathematically) less than or equal to the
+	 * highest_level, or if there is a dynamic channel and the level is 
+	 * less than or equal to the debug level, the main loop must be
+	 * entered to see if the message should really be output.
+	 *
+	 * NOTE: this is UNLOCKED access to the logconfig.  However,
+	 * the worst thing that can happen is that a bad decision is made
+	 * about returning without logging, and that's not a big concern,
+	 * because that's a risk anyway if the logconfig is being
+	 * dynamically changed.
+	 */
+
+	return (ISC_TF(level <= lctx->logconfig->highest_level ||
+		       (lctx->logconfig->dynamic &&
+			level <= lctx->debug_level)));
+}
+
 static void
 isc_log_doit(isc_log_t *lctx, isc_logcategory_t *category,
 	     isc_logmodule_t *module, int level, isc_boolean_t write_once,
@@ -1232,24 +1256,7 @@ isc_log_doit(isc_log_t *lctx, isc_logcategory_t *category,
 	REQUIRE(category->id < lctx->category_count);
 	REQUIRE(module->id < lctx->module_count);
 
-	/*
-	 * Try to avoid locking the mutex for messages which can't
-	 * possibly be logged to any channels -- primarily debugging
-	 * messages that the debug level is not high enough to print.
-	 *
-	 * If the level is (mathematically) less than or equal to the
-	 * highest_level, or if there is a dynamic channel and the level is 
-	 * less than or equal to the debug level, the main loop must be
-	 * entered to see if the message should really be output.
-	 *
-	 * NOTE: this is UNLOCKED access to the logconfig.  However,
-	 * the worst thing that can happen is that a bad decision is made
-	 * about returning without logging, and that's not a big concern,
-	 * because that's a risk anyway if the logconfig is being
-	 * dynamically changed.
-	 */
-	if (! (level <= lctx->logconfig->highest_level ||
-	       (lctx->logconfig->dynamic && level <= lctx->debug_level)))
+	if (! isc_log_wouldlog(lctx, level))
 		return;
 
 	time_string[0]  = '\0';