prevent segfault if there is nothing to be read from device

gvalkov · gvalkov · commit 6be662d16c17 · 2012-11-08T20:38:55.000+02:00
Instead of segfaulting, _input.read() will return an empty tuple if
the device has nothing to offer.
diff --git a/README.rst b/README.rst
@@ -32,6 +32,9 @@ Changelog
 Development
 ^^^^^^^^^^^
 
+Fixes:
+    - ``device.read()`` will return an empty tuple if the device has
+      nothing to offer (instead of segfaulting).
 
 0.3.0 (Nov 06, 2012)
 ^^^^^^^^^^^^^^^^^^^^
diff --git a/evdev/device.py b/evdev/device.py
@@ -232,10 +232,6 @@ def read(self):
         Read multiple input events from device. This function returns a
         generator object that yields :class:`InputEvent
         <evdev.events.InputEvent>` instances.
-
-        .. warning:: Attempting to read from an input device that has no
-                     available data will result in a segmentation fault. Consider
-                     wrapping calls to ``read()`` in a ``select()``.
         '''
 
         # events -> [(sec, usec, type, code, val), ...]
diff --git a/evdev/input.c b/evdev/input.c
@@ -88,9 +88,10 @@ device_read_many(PyObject *self, PyObject *args)
     struct input_event event[64];
 
     size_t event_size = sizeof(struct input_event);
-    size_t nread;
+    size_t nread = read(fd, event, event_size*64);
 
-    nread = read(fd, event, event_size*64);
+    if (nread == -1)
+        return PyTuple_New(0);
 
     // Construct a list of event tuples, which we'll make sense of in Python
     for (i = 0 ; i < nread/event_size ; i++) {
