[gjs: 3/5] log: Allow logging thread ID of each message

[Cosimo Cecchi <cosimoc src gnome org>]

commit 37588badeb4b5333fd184933f74d4805cea46c1d
Author: Philip Chimento <philip chimento gmail com>
Date:   Sat Feb 17 23:20:23 2018 -0800

    log: Allow logging thread ID of each message
    
    In order to help debug race conditions, we add the GJS_DEBUG_THREAD
    environment variable, which will prefix each debug log message with the
    thread ID according to g_thread_self().

 util/log.cpp | 13 +++++++++++++
 1 file changed, 13 insertions(+)
---
diff --git a/util/log.cpp b/util/log.cpp
index afd3aa1..39fae4a 100644
--- a/util/log.cpp
+++ b/util/log.cpp
@@ -101,6 +101,8 @@ gjs_debug(GjsDebugTopic topic,
     static bool debug_log_enabled = false;
     static bool checked_for_timestamp = false;
     static bool print_timestamp = false;
+    static bool checked_for_thread = false;
+    static bool print_thread = false;
     static GTimer *timer = NULL;
     const char *prefix;
     va_list args;
@@ -111,6 +113,11 @@ gjs_debug(GjsDebugTopic topic,
         checked_for_timestamp = true;
     }
 
+    if (!checked_for_thread) {
+        print_thread = gjs_environment_variable_is_set("GJS_DEBUG_THREAD");
+        checked_for_thread = true;
+    }
+
     if (print_timestamp && !timer) {
         timer = g_timer_new();
     }
@@ -275,6 +282,12 @@ _Pragma("GCC diagnostic pop")
         previous = total;
     }
 
+    if (print_thread) {
+        char *s2 = g_strdup_printf("(thread %p) %s", g_thread_self(), s);
+        g_free(s);
+        s = s2;
+    }
+
     write_to_stream(logfp, prefix, s);
 
     g_free(s);