Add a non-blocking freenect_process_events_timeout().

This should make it easier to integrate libfreenect into some other event loop.

Fixes #43.

Signed-off-by: Drew Fisher <drew.m.fisher@gmail.com>

include/libfreenect.h

@@ -231,6 +231,18 @@ FREENECTAPI void freenect_set_log_callback(freenect_context *ctx, freenect_log_c
  */
 FREENECTAPI int freenect_process_events(freenect_context *ctx);
 
+/**
+ * Calls the platform specific usb event processor until either an event occurs
+ * or the timeout parameter time has passed.  If a zero timeval is passed, this
+ * function will handle any already-pending events, then return immediately.
+ *
+ * @param ctx Context to process events for
+ * @param timeout Pointer to a timeval containing the maximum amount of time to block waiting for events, or zero for nonblocking mode
+ *
+ * @return 0 on success, other values on error, platform/library dependant
+ */
+FREENECTAPI int freenect_process_events_timeout(freenect_context *ctx, struct timeval* timeout);
+
 /**
  * Return the number of kinect devices currently connected to the
  * system

platform/windows/libusb10emu/libusb-1.0/libusb.h

@@ -96,6 +96,7 @@ int libusb_submit_transfer(struct libusb_transfer* transfer);
 int libusb_cancel_transfer(struct libusb_transfer* transfer);
 
 int libusb_handle_events(libusb_context* ctx);  // WORK IN PROGRESS...
+int libusb_handle_events_timeout(libusb_context* ctx, struct timeval* timeout);
 
 // the signature of libusb_device_descriptor is identical to usb_device_descriptor
 // which means that the below struct could be replaced by a typedef; however, that

platform/windows/libusb10emu/libusb-1.0/libusbemu.cpp

@@ -624,6 +624,25 @@ int libusb_handle_events(libusb_context* ctx)
   return(0);
 }
 
+int libusb_handle_events_timeout(libusb_context* ctx, struct timeval* timeout)
+{
+  if (ctx == NULL)
+    ctx = default_context;
+
+  if (failguard::Abort())
+    return(LIBUSB_ERROR_INTERRUPTED);
+
+  RAIIMutex lock (ctx->mutex);
+
+  if (timeout == NULL)
+    libusbemu_handle_isochronous(ctx, 0);
+  else
+    libusbemu_handle_isochronous(ctx, (timeout->tv_sec * 1000) + (timeout->tv_usec / 1000));
+
+  // 0 on success, or a LIBUSB_ERROR code on failure
+  return(0);
+}
+
 void PreprocessTransferNaive(libusb_transfer* transfer, const int read);
 void PreprocessTransferFreenect(libusb_transfer* transfer, const int read);
 static void(*PreprocessTransfer)(libusb_transfer*, const int) (PreprocessTransferFreenect);

src/core.c

@@ -72,6 +72,11 @@ FREENECTAPI int freenect_process_events(freenect_context *ctx)
 	return fnusb_process_events(&ctx->usb);
 }
 
+FREENECTAPI int freenect_process_events_timeout(freenect_context *ctx, struct timeval *timeout)
+{
+	return fnusb_process_events_timeout(&ctx->usb, timeout);
+}
+
 FREENECTAPI int freenect_num_devices(freenect_context *ctx)
 {
 	return fnusb_num_devices(&ctx->usb);

src/usb_libusb10.c

@@ -152,6 +152,11 @@ int fnusb_process_events(fnusb_ctx *ctx)
 	return libusb_handle_events(ctx->ctx);
 }
 
+int fnusb_process_events_timeout(fnusb_ctx *ctx, struct timeval* timeout)
+{
+	return libusb_handle_events_timeout(ctx->ctx, timeout);
+}
+
 int fnusb_open_subdevices(freenect_device *dev, int index)
 {
 	freenect_context *ctx = dev->parent;

src/usb_libusb10.h

@@ -89,6 +89,7 @@ int fnusb_list_device_attributes(fnusb_ctx *ctx, struct freenect_device_attribut
 int fnusb_init(fnusb_ctx *ctx, freenect_usb_context *usb_ctx);
 int fnusb_shutdown(fnusb_ctx *ctx);
 int fnusb_process_events(fnusb_ctx *ctx);
+int fnusb_process_events_timeout(fnusb_ctx *ctx, struct timeval* timeout);
 
 int fnusb_open_subdevices(freenect_device *dev, int index);
 int fnusb_close_subdevices(freenect_device *dev);