From 36594e191980d84ca77ba09faddf3f160a9839cf Mon Sep 17 00:00:00 2001
From: Georges Basile Stavracas Neto <georges.stavracas@gmail.com>
Date: Tue, 28 Sep 2021 21:00:35 -0300
Subject: [PATCH] displaystatetracker: Add match string

The monitor's match string is a unique string that can be used to compare
monitors and check for equality. It's composed of the product, vendor, and
serial numbers. It'll be used by the next commit to restore sessions.
---
 src/displaystatetracker.c | 18 +++++++++++++++---
 src/displaystatetracker.h |  2 ++
 2 files changed, 17 insertions(+), 3 deletions(-)

diff --git a/src/displaystatetracker.c b/src/displaystatetracker.c
index 6affd8a..fc9109e 100644
--- a/src/displaystatetracker.c
+++ b/src/displaystatetracker.c
@@ -35,6 +35,7 @@ static guint signals[N_SIGNALS];
 typedef struct _Monitor
 {
   char *connector;
+  char *match_string;
   char *display_name;
 } Monitor;
 
@@ -65,6 +66,7 @@ static void
 monitor_free (Monitor *monitor)
 {
   g_free (monitor->connector);
+  g_free (monitor->match_string);
   g_free (monitor->display_name);
   g_free (monitor);
 }
@@ -75,6 +77,12 @@ monitor_get_connector (Monitor *monitor)
   return monitor->connector;
 }
 
+const char *
+monitor_get_match_string (Monitor *monitor)
+{
+  return monitor->match_string;
+}
+
 const char *
 monitor_get_display_name (Monitor *monitor)
 {
@@ -109,6 +117,9 @@ generate_monitors (DisplayStateTracker *tracker,
   g_variant_iter_init (&monitors_iter, monitors);
   while ((monitor_variant = g_variant_iter_next_value (&monitors_iter)))
     {
+      g_autofree char *vendor = NULL;
+      g_autofree char *product = NULL;
+      g_autofree char *serial = NULL;
       Monitor *monitor;
       char *connector;
       char *display_name;
@@ -116,9 +127,9 @@ generate_monitors (DisplayStateTracker *tracker,
 
       g_variant_get (monitor_variant, "((ssss)a(siiddada{sv})@a{sv})",
                      &connector,
-                     NULL /* vendor */,
-                     NULL /* product */,
-                     NULL /* serial */,
+                     &vendor,
+                     &product,
+                     &serial,
                      NULL /* modes */,
                      &properties);
 
@@ -128,6 +139,7 @@ generate_monitors (DisplayStateTracker *tracker,
       monitor = g_new0 (Monitor, 1);
       *monitor = (Monitor) {
         .connector = connector,
+        .match_string = g_strdup_printf ("%s:%s:%s", vendor, product, serial),
         .display_name = display_name
       };
 
diff --git a/src/displaystatetracker.h b/src/displaystatetracker.h
index 54c63fa..1c3a7dc 100644
--- a/src/displaystatetracker.h
+++ b/src/displaystatetracker.h
@@ -28,6 +28,8 @@ G_DECLARE_FINAL_TYPE (DisplayStateTracker, display_state_tracker,
 
 const char * monitor_get_connector (Monitor *monitor);
 
+const char * monitor_get_match_string (Monitor *monitor);
+
 const char * monitor_get_display_name (Monitor *monitor);
 
 GList * logical_monitor_get_monitors (LogicalMonitor *logical_monitor);