lib/serialization: let refinements and subclasses access caches

[nit.git] / lib / serialization / caching.nit

diff --git a/lib/serialization/caching.nit b/lib/serialization/caching.nit
index 9be71f5..3554d22 100644 (file)
--- a/lib/serialization/caching.nit
+++ b/lib/serialization/caching.nit
@@ -24,6 +24,21 @@ abstract class CachingSerializer
 
        # Cache of known objects
        var cache = new SerializerCache is lazy, writable
+
+       # Link the cache of `self` with `deserializer`
+       #
+       # This allows reference objects by id when they are known by the other side
+       # of the stream.
+       #
+       # Use `cache` if it is a `DuplexCache`, otherwise create a new one.
+       fun link(deserializer: CachingDeserializer)
+       do
+               var mem = self.cache
+               if not mem isa DuplexCache then mem = new DuplexCache
+
+               self.cache = mem
+               deserializer.cache = mem
+       end
 end
 
 # A `Deserializer` with a `cache`
@@ -40,7 +55,7 @@ end
 # then using a reference.
 class SerializerCache
        # Map of already serialized objects to the reference id
-       private var sent: Map[Serializable, Int] = new StrictHashMap[Serializable, Int]
+       protected var sent: Map[Serializable, Int] = new StrictHashMap[Serializable, Int]
 
        # Is `object` known?
        fun has_object(object: Serializable): Bool do return sent.keys.has(object)
@@ -59,10 +74,13 @@ class SerializerCache
        # Require: `not has_object(object)`
        fun new_id_for(object: Serializable): Int
        do
-               var id = sent.length
+               var id = next_available_id
                sent[object] = id
                return id
        end
+
+       # Get a free id to associate to an object in the cache
+       protected fun next_available_id: Int do return sent.length
 end
 
 # Cache of received objects sorted by there reference id
@@ -70,7 +88,7 @@ end
 # Used by `Deserializer` to find already deserialized objects by their reference.
 class DeserializerCache
        # Map of references to already deserialized objects.
-       private var received: Map[Int, Object] = new StrictHashMap[Int, Object]
+       protected var received: Map[Int, Object] = new StrictHashMap[Int, Object]
 
        # Is there an object associated to `id`?
        fun has_id(id: Int): Bool do return received.keys.has(id)
@@ -101,3 +119,19 @@ class DuplexCache
                sent[object] = id
        end
 end
+
+# A shared cache where 2 clients serialize objects at the same types, prevents references collision
+class AsyncCache
+       super DuplexCache
+
+       # Should this end use even numbers?
+       var use_even: Bool
+
+       private var last_id: Int is lazy do return if use_even then 0 else 1
+
+       redef fun next_available_id
+       do
+               last_id += 2
+               return last_id
+       end
+end