Improve common/logging.c's support for multiple verbosity levels.

Instead of hard-wiring specific verbosity levels into the option
processing of client applications, invent pg_logging_increase_verbosity()
and encourage clients to implement --verbose by calling that.  Then,
the common convention that more -v's gets you more verbosity just works.

In particular, this allows resurrection of the debug-grade messages that
have long existed in pg_dump and its siblings.  They were unreachable
before this commit due to lack of a way to select PG_LOG_DEBUG logging
level.  (It appears that they may have been unreachable for some time
before common/logging.c was introduced, too, so I'm not specifically
blaming cc8d41511 for the oversight.  One reason for thinking that is
that it's now apparent that _allocAH()'s message needs a null-pointer
guard.  Testing might have failed to reveal that before 96bf88d52.)

Discussion: https://postgr.es/m/[email protected]

1 files changed, 18 insertions, 0 deletions

diff --git a/src/common/logging.c b/src/common/logging.c
index 6a3a437a34b..d9632fffc8a 100644
--- a/src/common/logging.c
+++ b/src/common/logging.c
@@ -157,12 +157,30 @@ pg_logging_config(int new_flags)
 	log_flags = new_flags;
 }
 
+/*
+ * pg_logging_init sets the default log level to INFO.  Programs that prefer
+ * a different default should use this to set it, immediately afterward.
+ */
 void
 pg_logging_set_level(enum pg_log_level new_level)
 {
 	__pg_log_level = new_level;
 }
 
+/*
+ * Command line switches such as --verbose should invoke this.
+ */
+void
+pg_logging_increase_verbosity(void)
+{
+	/*
+	 * The enum values are chosen such that we have to decrease __pg_log_level
+	 * in order to become more verbose.
+	 */
+	if (__pg_log_level > PG_LOG_NOTSET + 1)
+		__pg_log_level--;
+}
+
 void
 pg_logging_set_pre_callback(void (*cb) (void))
 {