From 8259c2e7064e5d03759de4a934fbb595949dae63 Mon Sep 17 00:00:00 2001
From: Peter Hutterer <peter.hutterer@who-t.net>
Date: Fri, 26 Jul 2019 08:50:29 +1000
Subject: [PATCH] ratbagd: introduce ref/unref for ratbagd_device pointers

We'll need to keep references around to devices even when caller is done with
them.

Signed-off-by: Peter Hutterer <peter.hutterer@who-t.net>
---
 ratbagd/ratbagd-device.c | 30 ++++++++++++++++++++++++++----
 ratbagd/ratbagd-test.c   |  2 +-
 ratbagd/ratbagd.c        |  4 ++--
 ratbagd/ratbagd.h        |  5 +++--
 4 files changed, 32 insertions(+), 9 deletions(-)

diff --git a/ratbagd/ratbagd-device.c b/ratbagd/ratbagd-device.c
index c8ef74eb..bc8d0cad 100644
--- a/ratbagd/ratbagd-device.c
+++ b/ratbagd/ratbagd-device.c
@@ -41,6 +41,8 @@
 #include "libratbag-util.h"
 
 struct ratbagd_device {
+	unsigned int refcount;
+
 	struct ratbagd *ctx;
 	RBNode node;
 	char *sysname;
@@ -230,7 +232,7 @@ int ratbagd_device_new(struct ratbagd_device **out,
 		       const char *sysname,
 		       struct ratbag_device *lib_device)
 {
-	_cleanup_(ratbagd_device_freep) struct ratbagd_device *device = NULL;
+	_cleanup_(ratbagd_device_unrefp) struct ratbagd_device *device = NULL;
 	struct ratbag_profile *profile;
 	unsigned int i;
 	int r;
@@ -240,6 +242,7 @@ int ratbagd_device_new(struct ratbagd_device **out,
 	assert(sysname);
 
 	device = zalloc(sizeof(*device));
+	device->refcount = 1;
 	device->ctx = ctx;
 	rbnode_init(&device->node);
 	device->lib_device = ratbag_device_ref(lib_device);
@@ -282,12 +285,12 @@ int ratbagd_device_new(struct ratbagd_device **out,
 	return 0;
 }
 
-struct ratbagd_device *ratbagd_device_free(struct ratbagd_device *device)
+static void ratbagd_device_free(struct ratbagd_device *device)
 {
 	unsigned int i;
 
 	if (!device)
-		return NULL;
+		return;
 
 	assert(!ratbagd_device_linked(device));
 
@@ -301,7 +304,26 @@ struct ratbagd_device *ratbagd_device_free(struct ratbagd_device *device)
 
 	assert(!device->lib_device); /* ratbag yields !NULL if still pinned */
 
-	return mfree(device);
+	mfree(device);
+}
+
+struct ratbagd_device *ratbagd_device_ref(struct ratbagd_device *device)
+{
+	assert(device->refcount > 0);
+
+	++device->refcount;
+	return device;
+}
+
+struct ratbagd_device *ratbagd_device_unref(struct ratbagd_device *device)
+{
+	assert(device->refcount > 0);
+
+	--device->refcount;
+	if (device->refcount == 0)
+		ratbagd_device_free(device);
+
+	return NULL;
 }
 
 const char *ratbagd_device_get_sysname(struct ratbagd_device *device)
diff --git a/ratbagd/ratbagd-test.c b/ratbagd/ratbagd-test.c
index fe5a4950..fca90192 100644
--- a/ratbagd/ratbagd-test.c
+++ b/ratbagd/ratbagd-test.c
@@ -185,7 +185,7 @@ int ratbagd_reset_test_device(sd_bus_message *m,
 
 	if (ratbagd_test_device) {
 		ratbagd_device_unlink(ratbagd_test_device);
-		ratbagd_device_free(ratbagd_test_device);
+		ratbagd_device_unref(ratbagd_test_device);
 
 		(void) sd_bus_emit_properties_changed(ctx->bus,
 						      RATBAGD_OBJ_ROOT,
diff --git a/ratbagd/ratbagd.c b/ratbagd/ratbagd.c
index 6c462b68..bac37e37 100644
--- a/ratbagd/ratbagd.c
+++ b/ratbagd/ratbagd.c
@@ -200,7 +200,7 @@ static void ratbagd_process_device(struct ratbagd *ctx,
 		/* device was removed, unlink it and destroy our context */
 		if (device) {
 			ratbagd_device_unlink(device);
-			ratbagd_device_free(device);
+			ratbagd_device_unref(device);
 
 			(void) sd_bus_emit_properties_changed(ctx->bus,
 							      RATBAGD_OBJ_ROOT,
@@ -283,7 +283,7 @@ static struct ratbagd *ratbagd_free(struct ratbagd *ctx)
 
 	RATBAGD_DEVICE_FOREACH_SAFE(device, tmp, ctx) {
 		ratbagd_device_unlink(device);
-		ratbagd_device_free(device);
+		ratbagd_device_unref(device);
 	}
 
 	ctx->bus = sd_bus_flush_close_unref(ctx->bus);
diff --git a/ratbagd/ratbagd.h b/ratbagd/ratbagd.h
index a3a6b045..a980db54 100644
--- a/ratbagd/ratbagd.h
+++ b/ratbagd/ratbagd.h
@@ -170,7 +170,8 @@ int ratbagd_device_new(struct ratbagd_device **out,
 		       struct ratbagd *ctx,
 		       const char *sysname,
 		       struct ratbag_device *lib_device);
-struct ratbagd_device *ratbagd_device_free(struct ratbagd_device *device);
+struct ratbagd_device *ratbagd_device_ref(struct ratbagd_device *device);
+struct ratbagd_device *ratbagd_device_unref(struct ratbagd_device *device);
 const char *ratbagd_device_get_sysname(struct ratbagd_device *device);
 const char *ratbagd_device_get_path(struct ratbagd_device *device);
 unsigned int ratbagd_device_get_num_buttons(struct ratbagd_device *device);
@@ -181,7 +182,7 @@ bool ratbagd_device_linked(struct ratbagd_device *device);
 void ratbagd_device_link(struct ratbagd_device *device);
 void ratbagd_device_unlink(struct ratbagd_device *device);
 
-DEFINE_TRIVIAL_CLEANUP_FUNC(struct ratbagd_device *, ratbagd_device_free);
+DEFINE_TRIVIAL_CLEANUP_FUNC(struct ratbagd_device *, ratbagd_device_unref);
 
 struct ratbagd_device *ratbagd_device_lookup(struct ratbagd *ctx,
 					     const char *name);