[meld] Set up file logging on Windows

[Kai Willadsen <kaiw src gnome org>]

commit 28102e3c14f5234b5df7e1205e18e518adcb2832
Author: Kai Willadsen <kai willadsen gmail com>
Date:   Tue Dec 31 08:36:26 2019 +1000

    Set up file logging on Windows
    
    In our Windows environment we don't generally get *any* logging for
    error cases, which makes crashes, etc. impossible to diagnose. This
    change makes it so that we at least have a log file available that
    *might* catch a traceback or something that we can use.

 bin/meld | 10 +++++++++-
 1 file changed, 9 insertions(+), 1 deletion(-)
---
diff --git a/bin/meld b/bin/meld
index ac72f0f2..2e60a46d 100755
--- a/bin/meld
+++ b/bin/meld
@@ -330,7 +330,15 @@ def setup_logging():
     else:
         log.setLevel(logging.CRITICAL)
 
-    handler = logging.StreamHandler()
+    if sys.platform == 'win32':
+        from gi.repository import GLib
+
+        log_path = os.path.join(GLib.get_user_data_dir(), "meld.log")
+        handler = logging.FileHandler(log_path)
+        log.setLevel(logging.INFO)
+    else:
+        handler = logging.StreamHandler()
+
     formatter = logging.Formatter("%(asctime)s %(levelname)s "
                                   "%(name)s: %(message)s")
     handler.setFormatter(formatter)