Add clear state

Server/MarkdownPreviewer/render_pipeline.py

@@ -2,7 +2,14 @@
 # Allows filtering and mapping based on blocks and meta keys.
 # 
 
-import pandoc
+from .pandoc import Pandoc
+
+class CallbackClass:
+    def __init__(self):
+        pass
+
+    def clear(self):
+        pass
 
 class MetaCallback:
     def __init__(self, key, callback, replace=False):
@@ -13,7 +20,10 @@ class MetaCallback:
     def __call__(self, data):
         return self.callback(data)
 
-class MultiCallback:
+    def clear(self):
+        pass
+
+class MultiCallback(CallbackClass):
     def __init__(self, filter):
         self.filter = filter
         self.callbacks = dict()
@@ -32,10 +42,15 @@ class MultiCallback:
         else:
             return block
 
+    def clear(self):
+        for key,value in self.callbacks.items():
+            if isinstance(value, CallbackClass):
+                value.clear()
+
 
 class RenderPipeline:
     def __init__(self):
-        self.pandoc = pandoc.Pandoc()
+        self.pandoc = Pandoc()
         self.metacallbacks = dict()
         self.callbacks = dict()
 
@@ -45,6 +60,13 @@ class RenderPipeline:
     def AddCallback(self, key, callback, replace=False):
         self.callbacks[key] = {'cb' : callback, 'replace' : replace}
 
+    def ClearState(self):
+        for key,value in self.metacallbacks.items():
+            value.clear()
+        for key,value in self.callbacks.items():
+            if isinstance(value['cb'], CallbackClass):
+                value['cb'].clear()
+
     def ParseBlock(self, block):
 
         if 'c' not in block:
@@ -76,6 +98,7 @@ class RenderPipeline:
         return output_list
 
     def __call__(self, data):
+        self.ClearState()
         json_data = self.pandoc.ConvertToJson(data)
 
         for meta_key, meta_value in json_data['meta'].items():