Add "time" to cancel()

Author: mgeier

src/rtmixer.c

@@ -55,29 +55,8 @@ int callback(const void* input, void* output, frame_t frameCount
       ; PaUtil_ReadRingBuffer(state->action_q, &action, 1)
       ;)
   {
-    // TODO: CANCEL with requested_time?
-
-    if (action->type == CANCEL)
-    {
-      CALLBACK_ASSERT(action->action);
-
-      struct action** actionaddr = &(state->actions);
-      while (*actionaddr)
-      {
-        if (*actionaddr == action->action)
-        {
-          remove_action(actionaddr, state);
-          break;
-        }
-        actionaddr = &((*actionaddr)->next);
-      }
-      // If the action wasn't in the list, we don't care
-
-      remove_action(&action, state);  // Remove the CANCEL action itself
-      continue;
-    }
-
-    // Actions are added at the beginning of the list, because it's easier:
+    // Actions are added at the beginning of the list, because CANCEL actions
+    // must come before the action they are cancelling.  Also, it's easier.
     action->next = state->actions;
     state->actions = action;
   }
@@ -87,8 +66,13 @@ int callback(const void* input, void* output, frame_t frameCount
   {
     struct action* const action = *actionaddr;
 
-    const bool playing = action->type == PLAY_BUFFER
-                      || action->type == PLAY_RINGBUFFER;
+    enum actiontype type = action->type;
+    if (type == CANCEL)
+    {
+      CALLBACK_ASSERT(action->action);
+      type = action->action->type;
+    }
+    const bool playing = type == PLAY_BUFFER || type == PLAY_RINGBUFFER;
 
     PaTime io_time = playing ? timeInfo->outputBufferDacTime
                              : timeInfo->inputBufferAdcTime;
@@ -126,6 +110,32 @@ int callback(const void* input, void* output, frame_t frameCount
       }
     }
 
+    if (action->type == CANCEL)
+    {
+      for (struct action** i = &(action->next); *i; i = &((*i)->next))
+      {
+        if (*i == action->action)
+        {
+          struct action* delinquent = *i;
+
+          if (delinquent->done_frames + offset > delinquent->total_frames)
+          {
+            // TODO: stops on its own ... set some error state?
+          }
+          else
+          {
+            delinquent->total_frames = delinquent->done_frames + offset;
+          }
+          // TODO: save some informations to action->...?
+          break;
+        }
+      }
+      // TODO: what if the action to cancel wasn't found? set actual_time = 0.0?
+
+      remove_action(actionaddr, state);  // Remove the CANCEL action itself
+      continue;
+    }
+
     frame_t frames = action->total_frames - action->done_frames;
 
     if (frameCount < frames)

src/rtmixer.h

@@ -22,7 +22,7 @@ struct action
     PaUtilRingBuffer* const ringbuffer;
     struct action* action;  // Used in CANCEL
   };
-  const frame_t total_frames;
+  frame_t total_frames;
   frame_t done_frames;
   // TODO: something to store the result of the action?
   // TODO: number of xruns during the runtime of the current action?

src/rtmixer.py

@@ -35,7 +35,7 @@ def actions(self):
         self._drain_result_q()
         return self._actions
 
-    def cancel(self, action):
+    def cancel(self, action, time=0, allow_belated=True):
         """Initiate stopping a running action.
 
         This creates another action that is sent to the callback in
@@ -47,6 +47,8 @@ def cancel(self, action):
         """
         cancel_action = _ffi.new('struct action*', dict(
             type=_lib.CANCEL,
+            allow_belated=allow_belated,
+            requested_time=time,
             action=action,
         ))
         self._enqueue(cancel_action)