/*
* Copyright (c) 2007 BUSINESS OBJECTS SOFTWARE LIMITED
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions are met:
*
* * Redistributions of source code must retain the above copyright notice,
* this list of conditions and the following disclaimer.
*
* * Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
*
* * Neither the name of Business Objects nor the names of its contributors
* may be used to endorse or promote products derived from this software
* without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
* AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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* LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
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*/
/*
* ValueNodeCommitHelper.java
* Creation date: Jul 22, 2003.
* By: Edward Lam
*/
package org.openquark.cal.valuenode;
import java.util.HashMap;
import java.util.Map;
import org.openquark.cal.compiler.ModuleTypeInfo;
import org.openquark.cal.compiler.TypeExpr;
/**
* This is a helper class that can be used to calculate the changes that would take place when a value node is committed,
* and that value node is type-linked to other value nodes.
* <p>
*
* For instance, in the case of an add gem, the two arguments to the gem are type-linked; the types of the two arguments are the same.
* <ul>
* <li>If one of the arguments is of type Double, then the other argument is also of type Double.
* <li>If both arguments are Doubles, and one of the arguments is switched to the Int type, the other argument must also
* be switched to the Int type, otherwise there will be an inconsistency.
* </ul>
*
* To use this class:
* <ol>
* <li>create a map from value node to unconstrained type, for every value node for which type-switching is possible.
* Care should be taken to maintain the desired referential equality among the given unconstrained type expr.
* <p>
* eg. In the case of an add gem, two value nodes would both be mapped to the same <code>(Num a => a -> a)</code> TypeExpr object.
*
* <li>when a value node is committed, call getCommitValues(). A map will be returned, where every value in the above map
* is mapped to its new value after the commit.
* <p>
* eg. In the case of an add gem, if the two value nodes are associated as in (1), a commit to one value will cause
* both associated value nodes to appear as keys in the returned map (since they both would change). These will
* be mapped to the new values that would appear on commit/type-switch.
* </li>
*
* @author Edward Lam
*/
public class ValueNodeCommitHelper {
private final ValueNodeBuilderHelper valueNodeBuilderHelper;
private final ValueNodeTransformer valueNodeTransformer;
/**
* Constructor for a ValueNodeCommitHelper.
* @param valueNodeBuilderHelper
* @param valueNodeTransformer
*/
public ValueNodeCommitHelper(ValueNodeBuilderHelper valueNodeBuilderHelper, ValueNodeTransformer valueNodeTransformer) {
this.valueNodeBuilderHelper = valueNodeBuilderHelper;
this.valueNodeTransformer = valueNodeTransformer;
}
/**
* Get the new values that would come out of a value commit.
* @param oldValueNode the value node whose type is being switched
* @param newValueNode the value node to which oldValueNode is being switched.
* @param valueNodeToUnconstrainedTypeMap The mapping from value node to its unconstrained type.
* Care should be taken to maintain the desired referential equality among type expr in the map.
* eg. ValueNodes with the same TypeExpr reference will be switched together.
* @return Map A map from old value node to the new values they would have on switch.
* An entry will be present for each value node in the valueNodeToUnconstrainedTypeMap.
*/
public Map<ValueNode, ValueNode> getCommitValues(ValueNode oldValueNode, ValueNode newValueNode, Map<ValueNode, TypeExpr> valueNodeToUnconstrainedTypeMap) {
int nTypes = valueNodeToUnconstrainedTypeMap.size();
ValueNode[] oldValueNodes = new ValueNode[nTypes];
TypeExpr[] oldSpecializedTypes = new TypeExpr[nTypes];
TypeExpr[] unconstrainedTypes = new TypeExpr[nTypes];
int switchIndex = -1;
int index = 0;
for (final Map.Entry<ValueNode, TypeExpr> entry : valueNodeToUnconstrainedTypeMap.entrySet()) {
ValueNode valueNode = entry.getKey();
oldValueNodes[index] = valueNode;
oldSpecializedTypes[index] = valueNode.getTypeExpr();
unconstrainedTypes[index] = entry.getValue();
if (valueNode == oldValueNode) {
switchIndex = index;
}
index++;
}
TypeExpr switchedType = newValueNode.getTypeExpr();
ModuleTypeInfo currentModuleTypeInfo = valueNodeBuilderHelper.getPerspective().getWorkingModuleTypeInfo();
TypeExpr[] updatedSpecializedTypes = TypeExpr.getUpdatedSpecializedTypes(switchedType, switchIndex, oldSpecializedTypes, unconstrainedTypes, currentModuleTypeInfo);
if (updatedSpecializedTypes == null) {
//this is not a valid type switch. Perhaps there should be better validation here.
throw new IllegalStateException();
}
// Construct a map giving the new values.
Map<ValueNode, ValueNode> oldToNewValueMap = new HashMap<ValueNode, ValueNode>();
// Iterate through the affected values.
for (int i = 0; i < nTypes; ++i) {
ValueNode valueNode = oldValueNodes[i];
TypeExpr updatedSpecializedType = updatedSpecializedTypes[i];
ValueNode newValue;
if (i == switchIndex) {
// Make a copy of the value node which changed, ensuring that it has the updated type.
newValue = newValueNode.copyValueNode(); //updatedSpecializedType);
} else {
// Transmute to convert the old value to the new type.
newValue = valueNode.copyValueNode().transmuteValueNode(valueNodeBuilderHelper, valueNodeTransformer, updatedSpecializedType);
}
oldToNewValueMap.put(valueNode, newValue);
}
return oldToNewValueMap;
}
}