Add a 'hasDataChanged()' method to the 'Input' class

beat/backend/python/inputs.py

@@ -78,20 +78,23 @@ class Input:
 
     def __init__(self, name, data_format, data_source):
 
-        self.group               = None
-        self.name                = str(name)
-        self.data                = None
-        self.data_index          = -1
-        self.data_index_end      = -1
-        self.data_same_as_previous = False
-        self.data_format         = data_format
-        self.data_source         = data_source
-        self.nb_data_blocks_read = 0
+        self.group                 = None
+        self.name                  = str(name)
+        self.data                  = None
+        self.data_index            = -1
+        self.data_index_end        = -1
+        self.data_same_as_previous = True
+        self.data_format           = data_format
+        self.data_source           = data_source
+        self.nb_data_blocks_read   = 0
 
 
     def isDataUnitDone(self):
         """Indicates if the current data unit will change at the next iteration"""
 
+        if (self.data_index_end >= 0) and (self.group.data_index_end == -1):
+            return True
+
         return (self.data_index_end == self.group.data_index_end)
 
 
@@ -101,9 +104,19 @@ class Input:
         return self.data_source.hasMoreData()
 
 
+    def hasDataChanged(self):
+        """Indicates if the current data unit is different than the one at the
+        previous iteration"""
+
+        return not self.data_same_as_previous
+
+
     def next(self):
         """Retrieves the next block of data"""
 
+        if self.group.restricted_access:
+            raise RuntimeError('Not authorized')
+
         (self.data, self.data_index, self.data_index_end) = self.data_source.next()
 
         if self.data is None:
@@ -229,6 +242,29 @@ class RemoteInput:
         return answer == 'tru'
 
 
+    def hasDataChanged(self):
+        """Indicates if the current data unit is different than the one at the
+        previous iteration"""
+
+        logger.debug('send: (hdc) has-data-changed %s %s', self.group.channel, self.name)
+
+        _start = time.time()
+
+        self.socket.send('hdc', zmq.SNDMORE)
+        self.socket.send(self.group.channel, zmq.SNDMORE)
+        self.socket.send(self.name)
+
+        answer = self.socket.recv()
+
+        self.comm_time += time.time() - _start
+        logger.debug('recv: %s', answer)
+
+        if answer == 'err':
+            process_error(self.socket)
+
+        return answer == 'tru'
+
+
     def next(self):
         """Retrieves the next block of data"""
 

beat/backend/python/message_handler.py

@@ -75,6 +75,7 @@ class MessageHandler(threading.Thread):
         self.callbacks = dict(
             nxt = self.next,
           hmd = self.has_more_data,
+          hdc = self.has_data_changed,
           idd = self.is_dataunit_done,
           don = self.done,
           err = self.error,
@@ -251,6 +252,16 @@ class MessageHandler(threading.Thread):
         self.socket.send(what)
 
 
+    def has_data_changed(self, channel, name):
+        """Syntax: hdc channel name"""
+
+        logger.debug('recv: hdc %s %s', channel, name)
+        input_candidate = self._get_input_candidate(channel, name)
+        what = 'tru' if input_candidate.hasDataChanged() else 'fal'
+        logger.debug('send: %s', what)
+        self.socket.send(what)
+
+
     def is_dataunit_done(self, channel, name):
         """Syntax: idd channel name"""