Initial preparations for container handling.

This rips out the port of a previous approach, stubs the current one
that is needed for Rakudo, and updates the serializer for it.

src/vm/jvm/runtime/org/perl6/nqp/runtime/GlobalContext.java

@@ -2,6 +2,7 @@
 
 import java.util.HashMap;
 
+import org.perl6.nqp.sixmodel.ContainerConfigurer;
 import org.perl6.nqp.sixmodel.KnowHOWBootstrapper;
 import org.perl6.nqp.sixmodel.SerializationContext;
 import org.perl6.nqp.sixmodel.SixModelObject;
@@ -121,6 +122,11 @@ public class GlobalContext {
      */
     public HashMap<String, SixModelObject> compilerRegistry;
 
+    /**
+     * Container configurer registry.
+     */
+    public HashMap<String, ContainerConfigurer> contConfigs;
+
     /**
      * Serialization context lookup hash.
      */
@@ -148,6 +154,8 @@ public GlobalContext()
         compilerRegistry = new HashMap<String, SixModelObject>();
         hllSyms = new HashMap<String, HashMap<String, SixModelObject>>();
 
+        contConfigs = new HashMap<String, ContainerConfigurer>();
+
         mainThread = new ThreadContext(this);
         KnowHOWBootstrapper.bootstrap(mainThread);
 

src/vm/jvm/runtime/org/perl6/nqp/sixmodel/ContainerConfigurer.java

@@ -0,0 +1,14 @@
+package org.perl6.nqp.sixmodel;
+import org.perl6.nqp.runtime.ThreadContext;
+
+/**
+ * A container configurer knows how to attach a certain type of container
+ * to an STable and configure it.
+ */
+public abstract class ContainerConfigurer {
+    /* Sets this container spec in place for the specified STable. */ 
+    public abstract void setContainerSpec(ThreadContext tc, STable st);
+
+    /* Configures the container spec with the specified info. */
+    public abstract void configureContainerSpec(ThreadContext tc, STable st, SixModelObject config);
+}

src/vm/jvm/runtime/org/perl6/nqp/sixmodel/ContainerSpec.java

@@ -1,27 +1,28 @@
 package org.perl6.nqp.sixmodel;
+import org.perl6.nqp.runtime.ThreadContext;
 
 /**
- * Language interop information that we hold if the type is declaring a
- * container of some sort.
+ * A scalar container has a ContainerSpec hung off its STable. It should be a
+ * subclass of this abstract base class.
  */
-public class ContainerSpec {
-    /**
-     * Class handle where we find the contained value.
-     */
-    SixModelObject ClassHandle;
+public abstract class ContainerSpec {
+    /* Fetches a value out of a container. Used for decontainerization. */
+    public abstract SixModelObject fetch(ThreadContext tc, SixModelObject cont);
 
-    /**
-     * Attribute name where we find the contained value.
-     */
-    String AttrName;
+    /* Stores a value in a container. Used for assignment. */
+    public abstract void store(ThreadContext tc, SixModelObject cont, SixModelObject obj);
 
-    /**
-     * Attribute lookup hint used in gradual typing.
-     */
-    int Hint;
+    /* Stores a value in a container, without any checking of it (this
+     * assumes an optimizer or something else already did it). Used for
+     * assignment. */
+    public abstract void storeUnchecked(ThreadContext tc, SixModelObject cont, SixModelObject obj);
 
-    /**
-     * FETCH method if applicable.
-     */
-    SixModelObject FetchMethod;
+    /* Name of this container specification. */
+    public String name;
+
+    /* Serializes the container data, if any. */
+    public abstract void serialize(ThreadContext tc, STable st, SerializationWriter writer);
+
+    /* Deserializes the container data, if any. */
+    public abstract void deserialize(ThreadContext tc, STable st, SerializationReader reader);
 }

src/vm/jvm/runtime/org/perl6/nqp/sixmodel/SerializationReader.java

@@ -328,11 +328,17 @@ private void deserializeSTables() {
 
             /* Container spec. */
             if (orig.getLong() != 0) {
-                st.ContainerSpec = new ContainerSpec();
-                st.ContainerSpec.ClassHandle = readRef();
-                st.ContainerSpec.AttrName = lookupString(orig.getInt());
-                st.ContainerSpec.Hint = (int)orig.getLong();
-                st.ContainerSpec.FetchMethod = readRef();
+                if (version >= 5) {
+                    String ccName = readStr();
+                    ContainerConfigurer cc = tc.gc.contConfigs.get(ccName);
+                    if (cc == null)
+                        throw new RuntimeException("Unknown container config " + ccName);
+                    cc.setContainerSpec(tc, st);
+                    st.ContainerSpec.deserialize(tc, st, this);
+                }
+                else {
+                    throw new RuntimeException("Unable to deserialize old container spec format");
+                }
             }
 
             /* Invocation spec. */

src/vm/jvm/runtime/org/perl6/nqp/sixmodel/SerializationWriter.java

@@ -533,10 +533,8 @@ private void serializeStable(STable st) {
         /* Container spec. */
         writeInt(st.ContainerSpec == null ? 0 : 1);
         if (st.ContainerSpec != null) {
-            writeRef(st.ContainerSpec.ClassHandle);
-            writeStr(st.ContainerSpec.AttrName);
-            writeInt(st.ContainerSpec.Hint);
-            writeRef(st.ContainerSpec.FetchMethod);
+            writeStr(st.ContainerSpec.name);
+            st.ContainerSpec.serialize(tc, st, this);
         }
 
         /* Invocation spec. */