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package org.jruby.ast;

import org.jruby.Ruby;

import org.jruby.RubyModule;

import org.jruby.exceptions.JumpException;

import org.jruby.javasupport.util.RuntimeHelpers;

import org.jruby.lexer.yacc.ISourcePosition;

import org.jruby.runtime.Block;

import org.jruby.runtime.ThreadContext;

import org.jruby.runtime.builtin.IRubyObject;

import org.jruby.util.ByteList;

/**

*

* @author enebo

*/

public class Colon2ConstNode extends Colon2Node {

private volatile transient IRubyObject cachedValue = null;

private volatile Object generation = -1;

private volatile int hash = -1;

public Colon2ConstNode(ISourcePosition position, Node leftNode, String name) {

super(position, leftNode, name);

assert leftNode != null: "Colon2ConstNode cannot have null leftNode";

}

@Override

public IRubyObject interpret(Ruby runtime, ThreadContext context, IRubyObject self, Block aBlock) {

RubyModule target = RuntimeHelpers.checkIsModule(leftNode.interpret(runtime, context, self, aBlock));

IRubyObject value = getValue(context, target);

return value != null ? value : target.getConstantFromConstMissing(name);

}

@Override

public ByteList definition(Ruby runtime, ThreadContext context, IRubyObject self, Block aBlock) {

IRubyObject lastError = context.getErrorInfo();

try {

if (RuntimeHelpers.isModuleAndHasConstant(leftNode.interpret(runtime, context, self, aBlock), name)) return CONSTANT_BYTELIST;

} catch (JumpException e) {

// replace lastError

context.setErrorInfo(lastError);

}

return null;

}

public IRubyObject getValue(ThreadContext context, RubyModule target) {

IRubyObject value = cachedValue; // Store to temp so it does null out on us mid-stream

return isCached(context, target, value) ? value : reCache(context, target);

}

private boolean isCached(ThreadContext context, RubyModule target, IRubyObject value) {

// We could probably also detect if LHS value came out of cache and avoid some of this

return

value != null &&

generation == context.getRuntime().getConstantInvalidator().getData() &&

hash == target.hashCode();

}

public IRubyObject reCache(ThreadContext context, RubyModule target) {

Object newGeneration = context.getRuntime().getConstantInvalidator().getData();

IRubyObject value = target.getConstantFromNoConstMissing(name);

cachedValue = value;

if (value != null) {

generation = newGeneration;

hash = target.hashCode();

}

return value;

}

}