input_plugin: add method check()

To check for errors without reading.  The decoder thread wants to do
that, before it passes the input stream to the plugin.

1 files changed, 8 insertions, 0 deletions

diff --git a/src/input_plugin.h b/src/input_plugin.h
index 3ac0bdf40..4e0993d12 100644
--- a/src/input_plugin.h
+++ b/src/input_plugin.h
@@ -52,6 +52,14 @@ struct input_plugin {
 	void (*close)(struct input_stream *is);
 
 	/**
+	 * Check for errors that may have occurred in the I/O thread.
+	 * May be unimplemented for synchronous plugins.
+	 *
+	 * @return false on error
+	 */
+	bool (*check)(struct input_stream *is, GError **error_r);
+
+	/**
 	 * Update the public attributes.  Call before access.  Can be
 	 * NULL if the plugin always keeps its attributes up to date.
 	 */