/*
* 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
* ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
* LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
* CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
* SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
* INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
* CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
* ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
* POSSIBILITY OF SUCH DAMAGE.
*/
/*
* RTDeepSeq.java
* Created: July 12, 2005
* By: Greg McClement
*/
package org.openquark.cal.internal.runtime.lecc.functions;
import org.openquark.cal.internal.runtime.lecc.LECCMachineConfiguration;
import org.openquark.cal.internal.runtime.lecc.RTExecutionContext;
import org.openquark.cal.internal.runtime.lecc.RTFullApp;
import org.openquark.cal.internal.runtime.lecc.RTResultFunction;
import org.openquark.cal.internal.runtime.lecc.RTSupercombinator;
import org.openquark.cal.internal.runtime.lecc.RTValue;
import org.openquark.cal.internal.runtime.lecc.RTData.CAL_String;
import org.openquark.cal.runtime.CALExecutorException;
import org.openquark.cal.runtime.CalValue;
import org.openquark.cal.runtime.ErrorInfo;
/**
* Implements the built-in primitive function:
* error :: String -> a
* defined in the Prelude module.
* This is the error function with an extra hidden argument that contains the source position.
*
* The returned value is an RTValue.
*
* @author Greg McClement
*/
public final class RTError extends RTSupercombinator {
public static final RTError $instance = new RTError();
private RTError() {
// Empty constructor created for access control.
}
public static final RTError make(RTExecutionContext $ec) {
return RTError.$instance;
}
@Override
public int getArity() {
return 2;
}
@Override
public final RTValue f(final RTResultFunction rootNode, final RTExecutionContext $ec) throws CALExecutorException {
// Arguments
RTValue errorMessage = rootNode.getArgValue();
RTValue errorInfo = rootNode.prevArg().getArgValue();
// Release the fields in the root node to open them to garbage collection
rootNode.clearMembers();
return f2S(
RTValue.lastRef(errorInfo, errorInfo = null),
RTError.lastRef(errorMessage.evaluate($ec).getStringValue(), errorMessage = null),
$ec);
}
@Override
public final RTValue f2L(RTValue errorInfo, RTValue message, RTExecutionContext $ec) throws CALExecutorException {
return f2S(
RTValue.lastRef(errorInfo, errorInfo = null),
RTError.lastRef(message.evaluate($ec).getStringValue(), message = null),
$ec);
}
public final RTValue f2S(RTValue errorInfo, String message, RTExecutionContext $ec) throws CALExecutorException {
$ec.incrementNMethodCalls();
if (LECCMachineConfiguration.generateDebugCode() && $ec.isDebugProcessingNeeded(getQualifiedName())) {
$ec.debugProcessing(getQualifiedName(), new RTValue[]{errorInfo, CAL_String.make(message)});
}
// Top level supercombinator logic
return RTValue.errorCall((ErrorInfo) errorInfo.getOpaqueValue(), message);
}
/**
* {@inheritDoc}
*/
@Override
public final String getModuleName () {
//JUnit tested to equal its binding file value in RuntimeStringConstantsTest.
return "Cal.Core.Prelude";
}
/**
* {@inheritDoc}
*/
@Override
public final String getUnqualifiedName () {
//JUnit tested to equal its binding file value in RuntimeStringConstantsTest.
return "error";
}
/**
* {@inheritDoc}
*/
@Override
public final String getQualifiedName() {
//JUnit tested to equal its binding file value in RuntimeStringConstantsTest.
return "Cal.Core.Prelude.error";
}
/**
* lastRef is used as a means of nulling out local fields/variables
* at the same time they are being passed to as arguments in a method call.
* For example:
* myclass.myMethod(RTValue.lastRef(arg, arg = null));
* This is, of course, only used if there are no further references to the
* local in the code containing the method call.
*
* In essence this removes the local reference after it has been passed to
* myMethod but before myMethod is evaluated.
*
* The purpose behind these contortions is to make the object passed as a
* method argument available for garbage collection. Normally the local
* reference would prevent garbage collection until the call to myMethod
* returned and the local reference could be nulled out.
*
* If the argument is the root node of a dynamically expanded data structure
* (ex. a List) the reference to the root node will keep the entire structure
* in memory, even if the code in myMethod releases its reference to the root
* as it traverses the data structure. By nulling out the local using lastRef
* the garbage collector can collect the traversed portion of the data
* structure, potentially significantly reducing the memory used.
*
* @param s
* @param v
* @return The value of the first argument.
*/
private static final String lastRef (String s, RTValue v) {
return s;
}
/**
* A fully saturated application of error.
* Note: This class doesn't need to implement getArity() or getArgCount()
* as a fully saturated application can be treated like a zero arity function.
* @author rcypher
*/
public static final class RTAppS extends RTFullApp {
private final RTError function;
private RTValue errorInfo;
private String message;
public RTAppS(RTError function, RTValue errorInfo, String message) {
assert (function != null && errorInfo != null && message != null) :
"Null argument in constructor for RTError.RTAppS.";
this.function = function;
this.errorInfo = errorInfo;
this.message = message;
}
@Override
protected final RTValue reduce(RTExecutionContext $ec) throws CALExecutorException {
if (result == null) {
setResult(function.f2S(errorInfo, message, $ec));
clearMembers();
}
return result;
}
@Override
public final void clearMembers() {
//we don't need to clear this.function, since it points to a singleton held by a static member field
errorInfo = null;
message = null;
}
/**
* {@inheritDoc}
*/
@Override
public final int debug_getNChildren() {
if (result != null) {
return super.debug_getNChildren();
}
return 2;
}
/**
* {@inheritDoc}
*/
@Override
public final CalValue debug_getChild(int childN) {
if (result != null) {
return super.debug_getChild(childN);
}
switch (childN) {
case 0:
return errorInfo;
case 1:
return CAL_String.make(message);
default:
throw new IndexOutOfBoundsException();
}
}
/**
* {@inheritDoc}
*/
@Override
public final String debug_getNodeStartText() {
if (result != null) {
return super.debug_getNodeStartText();
}
return "(" + function.getQualifiedName();
}
/**
* {@inheritDoc}
*/
@Override
public final String debug_getNodeEndText() {
if (result != null) {
return super.debug_getNodeEndText();
}
return ")";
}
/**
* {@inheritDoc}
*/
@Override
public final String debug_getChildPrefixText(int childN) {
if (result != null) {
return super.debug_getChildPrefixText(childN);
}
if (childN >= 0 && childN < 2) {
return " ";
}
throw new IndexOutOfBoundsException();
}
}
}