From: Krzysztof Opasiak <k.opasiak@samsung.com>
Date: Mon, 29 Jun 2015 17:06:25 +0000 (+0200)
Subject: Introduce device reference counting
X-Git-Tag: submit/tizen_common/20160317.155115~60
X-Git-Url: http://review.tizen.org/git/?a=commitdiff_plain;h=205c3d45ee4191d1653a633318ea81a2bb52cd3b;p=platform%2Fcore%2Fapi%2Fusb-host.git

Introduce device reference counting

We should not free() usb devices explicity in
libhusb_free_devices() but just decrement their refcount
and free only if it is realy necessary.

Change-Id: I8474942e0305c25b8f41abb4dd018ce5bc05c9ec
Signed-off-by: Krzysztof Opasiak <k.opasiak@samsung.com>
---

diff --git a/include/libhusb.h b/include/libhusb.h
index fa26362..868cee1 100644
--- a/include/libhusb.h
+++ b/include/libhusb.h
@@ -130,6 +130,10 @@ ssize_t libhusb_get_devices(libhusb_context *ctx, libhusb_device ***devs);
 
 void libhusb_free_devices(libhusb_device **list, int unref_devices);
 
+libhusb_device *libhusb_ref_device(libhusb_device *dev);
+
+void libhusb_unref_device(libhusb_device *dev);
+
 int libhusb_get_max_packet_size(libhusb_device *dev, uint8_t endpoint);
 
 uint8_t libhusb_get_bus_number(libhusb_device *dev);
diff --git a/src/libhusb.c b/src/libhusb.c
index 02ca338..415f8b1 100644
--- a/src/libhusb.c
+++ b/src/libhusb.c
@@ -23,14 +23,24 @@
 #include <stdlib.h>
 #include <sys/queue.h>
 
+#include "libhusb.h"
+#include "uref.h"
+#include "common.h"
+
 struct libhusb_context {
 	libusb_context *lusb_ctx;
 };
 
 struct libhusb_device {
+	struct uref ref;
 	libusb_device *lusb_dev;
 };
 
+static inline struct libhusb_device *to_libhusb_device(struct uref *_uref)
+{
+	return container_of(_uref, struct libhusb_device, ref);
+}
+
 struct libhusb_device_handle {
 	struct libusb_device_handle *lusb_dev_handle;
 };
@@ -105,6 +115,30 @@ int libhusb_get_port_numbers(libhusb_device *dev, uint8_t* port_numbers, int por
 	return port_num;
 }
 
+static void free_device(struct uref *uref)
+{
+	struct libhusb_device *dev = to_libhusb_device(uref);
+
+	libusb_unref_device(dev->lusb_dev);
+	free(dev);
+}
+
+static struct libhusb_device *alloc_device(libusb_device *lusb_dev)
+{
+	struct libhusb_device *dev;
+
+	dev = malloc(sizeof(*dev));
+	if (!dev)
+		goto out;
+
+	uref_init(&dev->ref, free_device);
+
+	libusb_ref_device(lusb_dev);
+	dev->lusb_dev = lusb_dev;
+out:
+	return dev;
+}
+
 ssize_t libhusb_get_devices(libhusb_context *context, libhusb_device ***devs)
 {
 	ssize_t len;
@@ -121,27 +155,43 @@ ssize_t libhusb_get_devices(libhusb_context *context, libhusb_device ***devs)
 		return -1;
 
 	list = calloc(len + 1, sizeof(*list));
-	if (!list) {
-		libusb_free_device_list(lusb_list, 1);
-		return -99; /* TODO  replace with propper error*/
-	}
+	if (!list)
+		goto free_lusb_list;
 
 	list[len] = NULL;
 	for (i = 0; i < len; i++) {
-		rdevice = malloc(sizeof(*rdevice));
-		if (!rdevice) {
-			libusb_free_device_list(lusb_list, 1);
-			return -99; /* TODO  replace with propper error*/
-		}
+		rdevice = alloc_device(lusb_list[i]);
+		if (!rdevice)
+			goto free_dev_list;
+
 		list[i] = rdevice;
-		list[i]->lusb_dev = lusb_list[i];
 	}
 
 	*devs = list;
 
-	libusb_free_device_list(lusb_list, 0);
+	libusb_free_device_list(lusb_list, 1);
 
 	return len;
+
+free_dev_list:
+	while (--i <= 0)
+		libhusb_unref_device(list[i]);
+	free(list);
+free_lusb_list:
+	libusb_free_device_list(lusb_list, 1);
+
+	return -99; /* TODO  replace with propper error*/
+}
+
+libhusb_device *libhusb_ref_device(libhusb_device *dev)
+{
+	uref_get(&dev->ref);
+	return dev;
+}
+
+void libhusb_unref_device(libhusb_device *dev)
+{
+	uref_put(&dev->ref);
 }
 
 void libhusb_free_devices(libhusb_device **list, int unref_devices)
@@ -151,14 +201,9 @@ void libhusb_free_devices(libhusb_device **list, int unref_devices)
 	if (!list)
 		return;
 
-	for (i = 0; list[i] != NULL; i++) {
-		if (unref_devices) {
-			struct libusb_device *devp = list[i]->lusb_dev;
-			assert(devp);
-			libusb_unref_device(devp);
-		}
-		free(list[i]);
-	}
+	for (i = 0; list[i] != NULL; i++)
+		if (unref_devices)
+			libhusb_unref_device(list[i]);
 
 	free(list);
 }
@@ -171,7 +216,7 @@ int libhusb_get_max_packet_size(libhusb_device *dev, uint8_t endpoint)
 
 	ret = libusb_get_max_iso_packet_size(dev->lusb_dev, endpoint);
 	if (ret < 0)
-		ret = usb_device_get_error_num(ret);
+		ret = -99;
 
 	return ret;
 }