From 4e118c154dde70e196c4381bd97790a9413c3552 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Ricardo=20Ca=C3=B1uelo?= <ricardo.canuelo@collabora.com>
Date: Thu, 30 Sep 2021 08:22:21 +0200
Subject: Add g_usb_device_get_string_descriptor_bytes_full

Some devices won't answer to a request with a 128-byte data buffer, this
allows the user to specify the size of the request data
buffer. g_usb_device_get_string_descriptor_bytes still uses the default
buffer size (128 bytes).
---
 gusb/gusb-device.c | 47 +++++++++++++++++++++++++++++++++++++++--------
 gusb/gusb-device.h | 19 ++++++++++++-------
 gusb/libgusb.ver   |  6 ++++++
 3 files changed, 57 insertions(+), 15 deletions(-)

(limited to 'gusb')

diff --git a/gusb/gusb-device.c b/gusb/gusb-device.c
index 16a5527..184bc39 100644
--- a/gusb/gusb-device.c
+++ b/gusb/gusb-device.c
@@ -916,9 +916,10 @@ g_usb_device_get_string_descriptor (GUsbDevice  *device,
 }
 
 /**
- * g_usb_device_get_string_descriptor_bytes:
+ * g_usb_device_get_string_descriptor_bytes_full:
  * @desc_index: the index for the string descriptor to retrieve
  * @langid: the language ID
+ * @length: size of the request data buffer
  * @error: a #GError, or %NULL
  *
  * Get a raw string descriptor from the device. The returned string should be freed
@@ -926,16 +927,17 @@ g_usb_device_get_string_descriptor (GUsbDevice  *device,
  *
  * Return value: (transfer full): a possibly UTF-16 string, or NULL on error.
  *
- * Since: 0.3.6
+ * Since: 0.3.8
  **/
 GBytes *
-g_usb_device_get_string_descriptor_bytes (GUsbDevice  *device,
-					  guint8       desc_index,
-					  guint16      langid,
-					  GError     **error)
+g_usb_device_get_string_descriptor_bytes_full (GUsbDevice  *device,
+					       guint8       desc_index,
+					       guint16      langid,
+					       gsize        length,
+					       GError     **error)
 {
 	gint rc;
-	unsigned char buf[128];
+	g_autofree guint8 *buf = g_malloc0(length);
 
 	g_return_val_if_fail (G_USB_IS_DEVICE (device), NULL);
 	g_return_val_if_fail (error == NULL || *error == NULL, NULL);
@@ -947,7 +949,7 @@ g_usb_device_get_string_descriptor_bytes (GUsbDevice  *device,
 
 	rc = libusb_get_string_descriptor (device->priv->handle,
 					   desc_index, langid,
-					   buf, sizeof(buf));
+					   buf, length);
 	if (rc < 0) {
 		g_usb_device_libusb_error_to_gerror (device, rc, error);
 		return NULL;
@@ -956,6 +958,35 @@ g_usb_device_get_string_descriptor_bytes (GUsbDevice  *device,
 	return g_bytes_new (buf, rc);
 }
 
+/**
+ * g_usb_device_get_string_descriptor_bytes:
+ * @desc_index: the index for the string descriptor to retrieve
+ * @langid: the language ID
+ * @error: a #GError, or %NULL
+ *
+ * Get a raw string descriptor from the device. The returned string should be freed
+ * with g_bytes_unref() when no longer needed.
+ * The descriptor will be at most 128 btes in length, if you need to
+ * issue a request with either a smaller or larger descriptor, you can
+ * use g_usb_device_get_string_descriptor_bytes_full instead.
+ *
+ * Return value: (transfer full): a possibly UTF-16 string, or NULL on error.
+ *
+ * Since: 0.3.6
+ **/
+GBytes *
+g_usb_device_get_string_descriptor_bytes (GUsbDevice  *device,
+					  guint8       desc_index,
+					  guint16      langid,
+					  GError     **error)
+{
+	return g_usb_device_get_string_descriptor_bytes_full(device,
+							     desc_index,
+							     langid,
+							     128,
+							     error);
+}
+
 typedef gssize (GUsbDeviceTransferFinishFunc) (GUsbDevice *device, GAsyncResult *res, GError **error);
 
 typedef struct {
diff --git a/gusb/gusb-device.h b/gusb/gusb-device.h
index 5430fb6..722104a 100644
--- a/gusb/gusb-device.h
+++ b/gusb/gusb-device.h
@@ -212,13 +212,18 @@ gboolean		 g_usb_device_set_interface_alt	(GUsbDevice	*device,
 							 guint8		 alt,
 							 GError		**error);
 
-gchar			*g_usb_device_get_string_descriptor (GUsbDevice *device,
-							 guint8		 desc_index,
-							 GError		**error);
-GBytes			*g_usb_device_get_string_descriptor_bytes (GUsbDevice *device,
-							 guint8		 desc_index,
-							 guint16	 langid,
-							 GError		**error);
+gchar			*g_usb_device_get_string_descriptor		(GUsbDevice	*device,
+									 guint8		 desc_index,
+									 GError		**error);
+GBytes			*g_usb_device_get_string_descriptor_bytes	(GUsbDevice	*device,
+									 guint8		 desc_index,
+									 guint16	 langid,
+									 GError		**error);
+GBytes			*g_usb_device_get_string_descriptor_bytes_full	(GUsbDevice	*device,
+									 guint8		 desc_index,
+									 guint16	 langid,
+									 gsize		 length,
+									 GError		**error);
 
 /* sync -- TODO: use GCancellable and GUsbSource */
 gboolean		 g_usb_device_control_transfer	(GUsbDevice	*device,
diff --git a/gusb/libgusb.ver b/gusb/libgusb.ver
index 7c9e044..f59d1a9 100644
--- a/gusb/libgusb.ver
+++ b/gusb/libgusb.ver
@@ -153,3 +153,9 @@ LIBGUSB_0.3.6 {
     g_usb_device_get_string_descriptor_bytes;
   local: *;
 } LIBGUSB_0.3.5;
+
+LIBGUSB_0.3.8 {
+  global:
+    g_usb_device_get_string_descriptor_bytes_full;
+  local: *;
+} LIBGUSB_0.3.6;
-- 
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