From 16867251179fd3742e576d4c3f6dd956d6058f75 Mon Sep 17 00:00:00 2001
From: John Cupitt <jcupitt@gmail.com>
Date: Tue, 10 Nov 2020 11:03:18 +0000
Subject: [PATCH] block annoying INFO messages on some older glibs

Some old glibs can display INFO messages by default. Block these
ourselves.

See https://github.com/libvips/libvips/issues/1876
---
 ChangeLog              |  1 +
 libvips/iofuncs/init.c | 38 +++++++++++++++++++++++++++++++-------
 2 files changed, 32 insertions(+), 7 deletions(-)

diff --git a/ChangeLog b/ChangeLog
index c2a3a01b..5d17d315 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -5,6 +5,7 @@
 - fix out of bounds read in tiffload
 - fix tiffsave region shrink mode [imgifty]
 - add missing flushes on write to target [harukizaemon]
+- hide info messages you could get with some older glibs [kleisauke]
 
 6/9/20 started 8.10.2
 - update magicksave/load profile handling [kelilevi]
diff --git a/libvips/iofuncs/init.c b/libvips/iofuncs/init.c
index aa1b5901..ecdc2f36 100644
--- a/libvips/iofuncs/init.c
+++ b/libvips/iofuncs/init.c
@@ -284,6 +284,24 @@ empty_log_handler( const gchar *log_domain, GLogLevelFlags log_level,
 {       
 }
 
+#if !GLIB_CHECK_VERSION( 2, 31, 0 )
+static void
+default_log_handler( const gchar *log_domain, GLogLevelFlags log_level,
+	const gchar *message, gpointer user_data )
+{
+	if( log_level & (G_LOG_LEVEL_DEBUG | G_LOG_LEVEL_INFO) ) {
+		const char *domains = g_getenv( "G_MESSAGES_DEBUG" );
+
+		if( !domains || 
+			(!g_str_equal( domains, "all" ) &&
+			 !g_strrstr( domains, log_domain )) ) 
+	  		return;
+	}
+
+	g_log_default_handler( log_domain, log_level, message, user_data );
+}
+#endif /*!GLIB_CHECK_VERSION( 2, 31, 0 )*/
+
 /* Attempt to set a minimum stacksize. This can be important on systems with a
  * very low default, like musl.
  */
@@ -318,17 +336,12 @@ set_stacksize( guint64 size )
 static void
 vips_verbose( void ) 
 {
-	/* Older glibs were showing G_LOG_LEVEL_{INFO,DEBUG} messages
-	 * by default
-	 */
-#if GLIB_CHECK_VERSION ( 2, 31, 0 )
 	const char *old;
 
 	old = g_getenv( "G_MESSAGES_DEBUG" );
 
-	if( !old ) {
+	if( !old ) 
 		g_setenv( "G_MESSAGES_DEBUG", G_LOG_DOMAIN, TRUE );
-	}
 	else if( !g_str_equal( old, "all" ) &&
 		!g_strrstr( old, G_LOG_DOMAIN ) ) {
 		char *new;
@@ -338,7 +351,6 @@ vips_verbose( void )
 
 		g_free( new );
 	}
-#endif /*GLIB_CHECK_VERSION( 2, 31, 0 )*/
 }
 
 /**
@@ -590,6 +602,18 @@ vips_init( const char *argv0 )
 		g_log_set_handler( G_LOG_DOMAIN, G_LOG_LEVEL_WARNING, 
 			empty_log_handler, NULL );
 
+#if !GLIB_CHECK_VERSION( 2, 31, 0 )
+	/* Older glibs can sometimes show G_LOG_LEVEL_{INFO,DEBUG} messages.
+	 * Block them ourselves. We test the env var inside the handler since
+	 * vips_verbose() can be toggled at runtime.
+	 *
+	 * Again, we should not call g_log_set_handler(), but this is the only
+	 * convenient way to fix this behaviour.
+	 */
+	g_log_set_handler( G_LOG_DOMAIN, G_LOG_LEVEL_INFO | G_LOG_LEVEL_DEBUG, 
+		default_log_handler, NULL );
+#endif /*!GLIB_CHECK_VERSION( 2, 31, 0 )*/
+
 	/* Set a minimum stacksize, if we can.
 	 */
         if( (vips_min_stack_size = g_getenv( "VIPS_MIN_STACK_SIZE" )) )