Made the Mac implementation robust to disconnects and re-connects while a device has an open handle.

mac/hid.c

@@ -40,12 +40,19 @@ struct hid_device_ {
 	IOHIDDeviceRef device_handle;
 	int blocking;
 	int uses_numbered_reports;
+	int disconnected;
 	CFStringRef run_loop_mode;
 	uint8_t *input_report_buf;
 	struct input_report *input_reports;
 	pthread_mutex_t mutex;
+	
+	hid_device *next;
 };
 
+/* Static list of all the devices open. This way when a device gets
+   disconnected, its hid_device structure can be marked as disconnected
+   from hid_device_removal_callback(). */
+static hid_device *device_list = NULL;
 
 static hid_device *new_hid_device(void)
 {
@@ -53,11 +60,75 @@ static hid_device *new_hid_device(void)
 	dev->device_handle = NULL;
 	dev->blocking = 1;
 	dev->uses_numbered_reports = 0;
+	dev->disconnected = 0;
+	dev->run_loop_mode = NULL;
+	dev->input_report_buf = NULL;
 	dev->input_reports = NULL;
+	dev->next = NULL;
+
+	pthread_mutex_init(&dev->mutex, NULL);
+	
+	/* Add the new record to the device_list. */
+	if (!device_list)
+		device_list = dev;
+	else {
+		hid_device *d = device_list;
+		while (d) {
+			if (!d->next) {
+				d->next = dev;
+				break;
+			}
+			d = d->next;
+		}
+	}
 	
 	return dev;
 }
 
+static void free_hid_device(hid_device *dev)
+{
+	if (!dev)
+		return;
+	
+	/* Delete any input reports still left over. */
+	struct input_report *rpt = dev->input_reports;
+	while (rpt) {
+		struct input_report *next = rpt->next;
+		free(rpt->data);
+		free(rpt);
+		rpt = next;
+	}
+
+	/* Free the string and the report buffer. The check for NULL
+	   is necessary here as CFRelease() doesn't handle NULL like
+	   free() and others do. */
+	if (dev->run_loop_mode)
+		CFRelease(dev->run_loop_mode);
+	free(dev->input_report_buf);
+
+	pthread_mutex_destroy(&dev->mutex);
+
+	/* Remove it from the device list. */
+	hid_device *d = device_list;
+	if (d == dev) {
+		device_list = d->next;
+	}
+	else {
+		while (d) {
+			if (d->next == dev) {
+				d->next = d->next->next;
+				break;
+			}
+			
+			d = d->next;
+		}
+	}
+
+	/* Free the structure itself. */
+	free(dev);
+	
+}
+
 static 	IOHIDManagerRef hid_mgr = 0x0;
 
 
@@ -346,6 +417,19 @@ hid_device * HID_API_EXPORT hid_open(unsigned short vendor_id, unsigned short pr
 	return handle;
 }
 
+static void hid_device_removal_callback(void *context, IOReturn result,
+                                        void *sender, IOHIDDeviceRef dev_ref)
+{
+	hid_device *d = device_list;
+	while (d) {
+		if (d->device_handle == dev_ref) {
+			d->disconnected = 1;
+		}
+		
+		d = d->next;
+	}
+}
+
 /* The Run Loop calls this function for each input report received.
    This function puts the data into a linked list to be picked up by
    hid_read(). */
@@ -430,8 +514,8 @@ hid_device * HID_API_EXPORT hid_open_path(const char *path)
 				IOHIDDeviceRegisterInputReportCallback(
 					os_dev, dev->input_report_buf, max_input_report_len,
 					&hid_report_callback, dev);
+				IOHIDManagerRegisterDeviceRemovalCallback(hid_mgr, hid_device_removal_callback, NULL);
 				
-				pthread_mutex_init(&dev->mutex, NULL);
 				
 				return dev;
 			}
@@ -444,7 +528,7 @@ hid_device * HID_API_EXPORT hid_open_path(const char *path)
 return_error:
 	free(device_array);
 	CFRelease(device_set);
-	free(dev);
+	free_hid_device(dev);
 	return NULL;
 }
 
@@ -454,6 +538,10 @@ static int set_report(hid_device *dev, IOHIDReportType type, const unsigned char
 	size_t length_to_send;
 	IOReturn res;
 
+	/* Return if the device has been disconnected. */
+   	if (dev->disconnected)
+   		return -1;
+
 	if (data[0] == 0x0) {
 		/* Not using numbered Reports.
 		   Don't send the report number. */
@@ -467,17 +555,20 @@ static int set_report(hid_device *dev, IOHIDReportType type, const unsigned char
 		length_to_send = length;
 	}
 	
-	res = IOHIDDeviceSetReport(dev->device_handle,
-	                           type,
-	                           data[0], /* Report ID*/
-	                           data_to_send, length_to_send);
+	if (!dev->disconnected) {
+		res = IOHIDDeviceSetReport(dev->device_handle,
+					   type,
+					   data[0], /* Report ID*/
+					   data_to_send, length_to_send);
 	
-	if (res == kIOReturnSuccess) {
-		return length;
+		if (res == kIOReturnSuccess) {
+			return length;
+		}
+		else
+			return -1;
 	}
-	else
-		return -1;
-
+	
+	return -1;
 }
 
 int HID_API_EXPORT hid_write(hid_device *dev, const unsigned char *data, size_t length)
@@ -512,6 +603,12 @@ int HID_API_EXPORT hid_read(hid_device *dev, unsigned char *data, size_t length)
 		ret_val = return_data(dev, data, length);
 		goto ret;
 	}
+
+	/* Return if the device has been disconnected. */
+   	if (dev->disconnected) {
+   		ret_val = -1;
+   		goto ret;
+	}
 	
 	/* There are no input reports queued up.
 	   Need to get some from the OS. */
@@ -527,6 +624,14 @@ int HID_API_EXPORT hid_read(hid_device *dev, unsigned char *data, size_t length)
 		while (1) {
 			code = CFRunLoopRunInMode(dev->run_loop_mode, 1000, TRUE);
 			
+			/* Return if the device has been disconnected */
+			if (code == kCFRunLoopRunFinished) {
+				dev->disconnected = 1;
+				ret_val = -1;
+				goto ret;
+			}
+
+
 			/* Return if some data showed up. */
 			if (dev->input_reports)
 				break;
@@ -543,6 +648,7 @@ int HID_API_EXPORT hid_read(hid_device *dev, unsigned char *data, size_t length)
 			goto ret;
 		}
 		else {
+			dev->disconnected = 1;
 			ret_val = -1; /* An error occured (maybe CTRL-C?). */
 			goto ret;
 		}
@@ -551,6 +657,13 @@ int HID_API_EXPORT hid_read(hid_device *dev, unsigned char *data, size_t length)
 		/* Non-blocking. See if the OS has any reports to give. */
 		SInt32 code;
 		code = CFRunLoopRunInMode(dev->run_loop_mode, 0, TRUE);
+		if (code == kCFRunLoopRunFinished) {
+			/* The run loop is finished, indicating an error
+			   or the device had been disconnected. */
+			dev->disconnected = 1;
+			ret_val = -1;
+			goto ret;
+		}
 		if (dev->input_reports) {
 			/* Return the first one */
 			ret_val = return_data(dev, data, length);
@@ -586,6 +699,10 @@ int HID_API_EXPORT hid_get_feature_report(hid_device *dev, unsigned char *data,
 	CFIndex len = length;
 	IOReturn res;
 
+	/* Return if the device has been unplugged. */
+	if (dev->disconnected)
+		return -1;
+
 	res = IOHIDDeviceGetReport(dev->device_handle,
 	                           kIOHIDReportTypeFeature,
 	                           data[0], /* Report ID */
@@ -602,24 +719,14 @@ void HID_API_EXPORT hid_close(hid_device *dev)
 	if (!dev)
 		return;
 	
-	/* Close the OS handle to the device. */
-	IOHIDDeviceClose(dev->device_handle, kIOHIDOptionsTypeNone);
-
-	/* Delete any input reports still left over. */
-	struct input_report *rpt = dev->input_reports;
-	while (rpt) {
-		struct input_report *next = rpt->next;
-		free(rpt->data);
-		free(rpt);
-		rpt = next;
+	/* Close the OS handle to the device, but only if it's not
+	   been unplugged. If it's been unplugged, then calling
+	   IOHIDDeviceClose() will crash. */
+	if (!dev->disconnected) {
+		IOHIDDeviceClose(dev->device_handle, kIOHIDOptionsTypeNone);
 	}
 
-	/* Free the string and the report buffer. */
-	CFRelease(dev->run_loop_mode);
-	free(dev->input_report_buf);
-	pthread_mutex_destroy(&dev->mutex);
-
-	free(dev);
+	free_hid_device(dev);
 }
 
 int HID_API_EXPORT_CALL hid_get_manufacturer_string(hid_device *dev, wchar_t *string, size_t maxlen)