[gnome-shell] log(): Reimplement on top of GLib.log_structured

[Jonh Wendell <jwendell src gnome org>]

commit 70526a80251b0f4c48144b389d741025715efbb6
Author: Jonh Wendell <jonh wendell redhat com>
Date:   Mon Oct 3 20:09:39 2016 -0300

    log(): Reimplement on top of GLib.log_structured
    
    This allows us to pass metadata fields besides the message
    to log. So, if the log() call is made from an extension,
    pass the extension name and UUID to the logger.
    
    This is useful for extension developers to debug their code
    as well as to instruct their users to send debug info to them
    by running something like this:
    
    journalctl GNOME_SHELL_EXTENSION_UUID=<extension@uuid>
    
    https://bugzilla.gnome.org/show_bug.cgi?id=770717

 configure.ac         |    2 +-
 js/ui/environment.js |   19 ++++++++++++++-----
 2 files changed, 15 insertions(+), 6 deletions(-)
---
diff --git a/configure.ac b/configure.ac
index 7d47643..b436a86 100644
--- a/configure.ac
+++ b/configure.ac
@@ -77,7 +77,7 @@ AC_MSG_RESULT($enable_systemd)
 
 CLUTTER_MIN_VERSION=1.21.5
 GOBJECT_INTROSPECTION_MIN_VERSION=1.49.1
-GJS_MIN_VERSION=1.39.0
+GJS_MIN_VERSION=1.47.0
 MUTTER_MIN_VERSION=3.22.1
 GTK_MIN_VERSION=3.15.0
 GIO_MIN_VERSION=2.45.3
diff --git a/js/ui/environment.js b/js/ui/environment.js
index 6fb23e3..68ddaa7 100644
--- a/js/ui/environment.js
+++ b/js/ui/environment.js
@@ -61,10 +61,19 @@ function _patchLayoutClass(layoutClass, styleProps) {
     };
 }
 
-function _makeLoggingFunc(func) {
-    return function() {
-        return func([].join.call(arguments, ', '));
-    };
+function _loggingFunc() {
+    let fields = {'MESSAGE': [].join.call(arguments, ', ')};
+    let domain = "GNOME Shell";
+
+    // If the caller is an extension, add it as metadata
+    let extension = imports.misc.extensionUtils.getCurrentExtension();
+    if (extension != null) {
+        domain = extension.metadata.name;
+        fields['GNOME_SHELL_EXTENSION_UUID'] = extension.uuid;
+        fields['GNOME_SHELL_EXTENSION_NAME'] = extension.metadata.name;
+    }
+
+    GLib.log_structured(domain, GLib.LogLevelFlags.LEVEL_MESSAGE, fields);
 }
 
 function init() {
@@ -72,7 +81,7 @@ function init() {
     // browser convention of having that namespace be called 'window'.)
     window.global = Shell.Global.get();
 
-    window.log = _makeLoggingFunc(window.log);
+    window.log = _loggingFunc;
 
     window._ = Gettext.gettext;
     window.C_ = Gettext.pgettext;