different approach to topology retrieval

* uses get_port, get_port_path, get_parent as suggested by Alan Stern
* adds parent_dev and port_number to the libusb device struct
* uses calloc on device struct, to handle currently missing backend implementations
* xusb updated to use new calls

8 files changed, 96 insertions, 84 deletions

diff --git a/examples/xusb.c b/examples/xusb.c
index 0ae896e..b1bfa39 100644
--- a/examples/xusb.c
+++ b/examples/xusb.c
@@ -605,7 +605,7 @@ int test_device(uint16_t vid, uint16_t pid)
 {
 	libusb_device_handle *handle;
 	libusb_device *dev;
-	struct libusb_device_topology topology;
+	uint8_t bus, port_path[8];
 	struct libusb_config_descriptor *conf_desc;
 	const struct libusb_endpoint_descriptor *endpoint;
 	int i, j, k, r;
@@ -629,8 +629,14 @@ int test_device(uint16_t vid, uint16_t pid)
 	}
 
 	dev = libusb_get_device(handle);
-	if (libusb_get_device_topology(dev, &topology) == LIBUSB_SUCCESS) {
-		printf("bus: %d, port: %d, depth: %d\n", topology.bus, topology.port, topology.depth);
+	bus = libusb_get_bus_number(dev);
+	r = libusb_get_port_path(dev, port_path, sizeof(port_path));
+	if (r > 0) {
+		printf("bus: %d, port path from HCD: %d", bus, port_path[0]);
+		for (i=1; i<r; i++) {
+			printf("->%d", port_path[i]);
+		}
+		printf("\n");
 	}
 
 	printf("\nReading device descriptor:\n");
diff --git a/libusb/core.c b/libusb/core.c
index 5ad5809..0e9f357 100644
--- a/libusb/core.c
+++ b/libusb/core.c
@@ -510,7 +510,7 @@ struct libusb_device *usbi_alloc_device(struct libusb_context *ctx,
 	unsigned long session_id)
 {
 	size_t priv_size = usbi_backend->device_priv_size;
-	struct libusb_device *dev = malloc(sizeof(*dev) + priv_size);
+	struct libusb_device *dev = calloc(1, sizeof(*dev) + priv_size);
 	int r;
 
 	if (!dev)
@@ -673,6 +673,55 @@ uint8_t API_EXPORTED libusb_get_bus_number(libusb_device *dev)
 }
 
 /** \ingroup dev
+ * Get the number of the port that a device is connected to
+ * \param dev a device
+ * \returns the port number (0 if not available)
+ */
+uint8_t API_EXPORTED libusb_get_port_number(libusb_device *dev)
+{
+	return dev->port_number;
+}
+
+/** \ingroup dev
+ * Get the list of all port numbers from root for the specified device
+ * \param dev a device
+ * \param path the array that should contain the port numbers
+ * \param path_len the maximum length of the array
+ * \returns the number of elements filled
+ * \returns LIBUSB_ERROR_OVERFLOW if the array is too small
+ */
+int API_EXPORTED libusb_get_port_path(libusb_device *dev, uint8_t* path, uint8_t path_len)
+{
+	int i = path_len;
+
+	while(dev) {
+		// HCDs can be listed as devices and would have port #0
+		// TODO: see how the other backends want to implement HCDs as parents
+		if (dev->port_number == 0)
+			break;
+		usbi_dbg("another one (addy: %d)", dev->device_address);
+		if (--i<0) {
+			return LIBUSB_ERROR_OVERFLOW;
+		}
+		path[i] = dev->port_number;
+		dev = dev->parent_dev;
+	}
+	memmove(path, &path[i], path_len-i);
+	return path_len-i;
+}
+
+/** \ingroup dev
+ * Get the the parent from the specified device
+ * \param dev a device
+ * \returns the device parent or NULL if not available
+ */
+DEFAULT_VISIBILITY
+libusb_device * LIBUSB_CALL libusb_get_parent(libusb_device *dev)
+{
+	return dev->parent_dev;
+}
+
+/** \ingroup dev
  * Get the address of the device on the bus it is connected to.
  * \param dev a device
  * \returns the device address
@@ -1454,28 +1503,6 @@ int API_EXPORTED libusb_attach_kernel_driver(libusb_device_handle *dev,
 		return LIBUSB_ERROR_NOT_SUPPORTED;
 }
 
-/** \ingroup dev
- * Returns topology information for a device
- *
- * \param dev the device to get topology properties from
- * \param topology the libusb_device_topology structure to be populated.
- * \returns 0 on success
- * \returns LIBUSB_ERROR_INVALID_PARAM if dev or topology are invalid
- * \returns LIBUSB_ERROR_NOT_SUPPORTED on platforms where the functionality
- * is not available
- * \returns another LIBUSB_ERROR code on other failure
- */
-
-int API_EXPORTED libusb_get_device_topology(libusb_device *dev,
-	struct libusb_device_topology* topology)
-{
-	usbi_dbg("");
-	if (dev == NULL || topology == NULL) {
-		return LIBUSB_ERROR_INVALID_PARAM;
-	}
-	return usbi_backend->get_device_topology(dev, topology);
-}
-
 /** \ingroup lib
  * Set message verbosity.
  *  - Level 0: no messages ever printed by the library (default)
diff --git a/libusb/libusb-1.0.def b/libusb/libusb-1.0.def
index 96c6ca6..d437796 100644
--- a/libusb/libusb-1.0.def
+++ b/libusb/libusb-1.0.def
@@ -240,16 +240,6 @@ EXPORTS
   libusb_get_device_list@24 = libusb_get_device_list
   libusb_get_device_list@28 = libusb_get_device_list
   libusb_get_device_list@32 = libusb_get_device_list
-  libusb_get_device_topology
-  libusb_get_device_topology@00 = libusb_get_device_topology
-  libusb_get_device_topology@04 = libusb_get_device_topology
-  libusb_get_device_topology@08 = libusb_get_device_topology
-  libusb_get_device_topology@12 = libusb_get_device_topology
-  libusb_get_device_topology@16 = libusb_get_device_topology
-  libusb_get_device_topology@20 = libusb_get_device_topology
-  libusb_get_device_topology@24 = libusb_get_device_topology
-  libusb_get_device_topology@28 = libusb_get_device_topology
-  libusb_get_device_topology@32 = libusb_get_device_topology
   libusb_get_max_iso_packet_size
   libusb_get_max_iso_packet_size@00 = libusb_get_max_iso_packet_size
   libusb_get_max_iso_packet_size@04 = libusb_get_max_iso_packet_size
@@ -280,6 +270,16 @@ EXPORTS
   libusb_get_next_timeout@24 = libusb_get_next_timeout
   libusb_get_next_timeout@28 = libusb_get_next_timeout
   libusb_get_next_timeout@32 = libusb_get_next_timeout
+  libusb_get_parent
+  libusb_get_parent@00 = libusb_get_parent
+  libusb_get_parent@04 = libusb_get_parent
+  libusb_get_parent@08 = libusb_get_parent
+  libusb_get_parent@12 = libusb_get_parent
+  libusb_get_parent@16 = libusb_get_parent
+  libusb_get_parent@20 = libusb_get_parent
+  libusb_get_parent@24 = libusb_get_parent
+  libusb_get_parent@28 = libusb_get_parent
+  libusb_get_parent@32 = libusb_get_parent
   libusb_get_pollfds
   libusb_get_pollfds@00 = libusb_get_pollfds
   libusb_get_pollfds@04 = libusb_get_pollfds
@@ -290,6 +290,26 @@ EXPORTS
   libusb_get_pollfds@24 = libusb_get_pollfds
   libusb_get_pollfds@28 = libusb_get_pollfds
   libusb_get_pollfds@32 = libusb_get_pollfds
+  libusb_get_port_number
+  libusb_get_port_number@00 = libusb_get_port_number
+  libusb_get_port_number@04 = libusb_get_port_number
+  libusb_get_port_number@08 = libusb_get_port_number
+  libusb_get_port_number@12 = libusb_get_port_number
+  libusb_get_port_number@16 = libusb_get_port_number
+  libusb_get_port_number@20 = libusb_get_port_number
+  libusb_get_port_number@24 = libusb_get_port_number
+  libusb_get_port_number@28 = libusb_get_port_number
+  libusb_get_port_number@32 = libusb_get_port_number
+  libusb_get_port_path
+  libusb_get_port_path@00 = libusb_get_port_path
+  libusb_get_port_path@04 = libusb_get_port_path
+  libusb_get_port_path@08 = libusb_get_port_path
+  libusb_get_port_path@12 = libusb_get_port_path
+  libusb_get_port_path@16 = libusb_get_port_path
+  libusb_get_port_path@20 = libusb_get_port_path
+  libusb_get_port_path@24 = libusb_get_port_path
+  libusb_get_port_path@28 = libusb_get_port_path
+  libusb_get_port_path@32 = libusb_get_port_path
   libusb_get_string_descriptor_ascii
   libusb_get_string_descriptor_ascii@00 = libusb_get_string_descriptor_ascii
   libusb_get_string_descriptor_ascii@04 = libusb_get_string_descriptor_ascii
diff --git a/libusb/libusb.h b/libusb/libusb.h
index a89e326..ba3d5f5 100644
--- a/libusb/libusb.h
+++ b/libusb/libusb.h
@@ -675,19 +675,6 @@ typedef struct libusb_device libusb_device;
  */
 typedef struct libusb_device_handle libusb_device_handle;
 
-/** \ingroup dev
- * Structure representing the topology of an USB device.
- */
-struct libusb_device_topology {
-	/** Opaque device handle to the USB parent (a Hub or a HCD) */
-	libusb_device* parent_dev;
-	/** Bus number to which the device is connected, as seen by the OS */
-	uint8_t bus;
-	/** Depth to HCD for this bus (0 depth means the HCD device) */
-	uint8_t depth;
-	/** Hub port onto which the device is plugged in, as seen by the OS */
-	uint8_t port;
-};
 
 /** \ingroup misc
  * Error codes. Most libusb functions return 0 on success or one of these
@@ -901,6 +888,9 @@ int LIBUSB_CALL libusb_get_config_descriptor_by_value(libusb_device *dev,
 void LIBUSB_CALL libusb_free_config_descriptor(
 	struct libusb_config_descriptor *config);
 uint8_t LIBUSB_CALL libusb_get_bus_number(libusb_device *dev);
+uint8_t LIBUSB_CALL libusb_get_port_number(libusb_device *dev);
+libusb_device * LIBUSB_CALL libusb_get_parent(libusb_device *dev);
+int LIBUSB_CALL libusb_get_port_path(libusb_device *dev, uint8_t* path, uint8_t path_length);
 uint8_t LIBUSB_CALL libusb_get_device_address(libusb_device *dev);
 int LIBUSB_CALL libusb_get_max_packet_size(libusb_device *dev,
 	unsigned char endpoint);
@@ -934,9 +924,6 @@ int LIBUSB_CALL libusb_detach_kernel_driver(libusb_device_handle *dev,
 int LIBUSB_CALL libusb_attach_kernel_driver(libusb_device_handle *dev,
 	int interface_number);
 
-int LIBUSB_CALL libusb_get_device_topology(struct libusb_device *dev,
-	struct libusb_device_topology *topology);
-
 /* async I/O */
 
 /** \ingroup asyncio
diff --git a/libusb/libusbi.h b/libusb/libusbi.h
index caceb65..8ade9c7 100644
--- a/libusb/libusbi.h
+++ b/libusb/libusbi.h
@@ -271,6 +271,8 @@ struct libusb_device {
 	struct libusb_context *ctx;
 
 	uint8_t bus_number;
+	uint8_t port_number;
+	struct libusb_device* parent_dev;
 	uint8_t device_address;
 	uint8_t num_configurations;
 
@@ -761,14 +763,6 @@ struct usbi_os_backend {
 	int (*attach_kernel_driver)(struct libusb_device_handle *handle,
 		int interface_number);
 
-	/* Return device topology. Optional.
-	 *
-	 * This function is called to populate a libusb_device_topology structure,
-	 * that allows to uniquely identify the location of a device on the system.
-	 */
-	int (*get_device_topology)(struct libusb_device *dev,
-		struct libusb_device_topology* topology);
-
 	/* Destroy a device. Optional.
 	 *
 	 * This function is called when the last reference to a device is
diff --git a/libusb/os/darwin_usb.c b/libusb/os/darwin_usb.c
index 163439d..37b8e2c 100644
--- a/libusb/os/darwin_usb.c
+++ b/libusb/os/darwin_usb.c
@@ -1097,10 +1097,6 @@ static int darwin_detach_kernel_driver (struct libusb_device_handle *dev_handle,
   return LIBUSB_ERROR_NOT_SUPPORTED;
 }
 
-static int darwin_get_device_topology(struct libusb_device *dev, struct libusb_device_topology* topology) {
-  return LIBUSB_ERROR_NOT_SUPPORTED;
-}
-
 static void darwin_destroy_device(struct libusb_device *dev) {
 }
 
@@ -1539,7 +1535,6 @@ const struct usbi_os_backend darwin_backend = {
 	.detach_kernel_driver = darwin_detach_kernel_driver,
 	.attach_kernel_driver = darwin_attach_kernel_driver,
 
-	.get_device_topology = darwin_get_device_topology,
 	.destroy_device = darwin_destroy_device,
 
 	.submit_transfer = darwin_submit_transfer,
diff --git a/libusb/os/linux_usbfs.c b/libusb/os/linux_usbfs.c
index 9f9b140..867893c 100644
--- a/libusb/os/linux_usbfs.c
+++ b/libusb/os/linux_usbfs.c
@@ -1318,12 +1318,6 @@ static int op_attach_kernel_driver(struct libusb_device_handle *handle,
 	return 0;
 }
 
-static int op_get_device_topology(struct libusb_device *dev,
-	struct libusb_device_topology* topology)
-{
-	return LIBUSB_ERROR_NOT_SUPPORTED;
-}
-
 static void op_destroy_device(struct libusb_device *dev)
 {
 	struct linux_device_priv *priv = __device_priv(dev);
@@ -2232,7 +2226,6 @@ const struct usbi_os_backend linux_usbfs_backend = {
 	.detach_kernel_driver = op_detach_kernel_driver,
 	.attach_kernel_driver = op_attach_kernel_driver,
 
-	.get_device_topology = op_get_device_topology,
 	.destroy_device = op_destroy_device,
 
 	.submit_transfer = op_submit_transfer,
diff --git a/libusb/os/windows_usb.c b/libusb/os/windows_usb.c
index 2435f76..b51dad0 100644
--- a/libusb/os/windows_usb.c
+++ b/libusb/os/windows_usb.c
@@ -1074,8 +1074,10 @@ static int init_device(struct libusb_device* dev, struct libusb_device* parent_d
 	}
 	dev->bus_number = parent_dev->bus_number;
 	priv->port = port_number;
+	dev->port_number = port_number;
 	priv->depth = parent_priv->depth + 1;
 	priv->parent_dev = parent_dev;
+	dev->parent_dev = parent_dev;
 	memset(&conn_info, 0, sizeof(conn_info));
 
 	if (priv->depth != 0) {	// Not a HCD hub
@@ -1845,17 +1847,6 @@ static void windows_destroy_device(struct libusb_device *dev)
 	windows_device_priv_release(dev);
 }
 
-static int windows_get_device_topology(struct libusb_device *dev, struct libusb_device_topology* topology)
-{
-	struct windows_device_priv *priv = __device_priv(dev);
-
-	topology->bus = dev->bus_number;
-	topology->depth = priv->depth;
-	topology->parent_dev = priv->parent_dev;
-	topology->port = priv->port;
-	return LIBUSB_SUCCESS;
-}
-
 static void windows_clear_transfer_priv(struct usbi_transfer *itransfer)
 {
 	struct windows_transfer_priv *transfer_priv = (struct windows_transfer_priv*)usbi_transfer_get_os_priv(itransfer);
@@ -2247,7 +2238,6 @@ const struct usbi_os_backend windows_backend = {
 	windows_detach_kernel_driver,
 	windows_attach_kernel_driver,
 
-	windows_get_device_topology,
 	windows_destroy_device,
 
 	windows_submit_transfer,