Binding.java
/*
***** BEGIN LICENSE BLOCK *****
* Version: EPL 1.0/GPL 2.0/LGPL 2.1
*
* The contents of this file are subject to the Eclipse Public
* License Version 1.0 (the "License"); you may not use this file
* except in compliance with the License. You may obtain a copy of
* the License at http://www.eclipse.org/legal/epl-v10.html
*
* Software distributed under the License is distributed on an "AS
* IS" basis, WITHOUT WARRANTY OF ANY KIND, either express or
* implied. See the License for the specific language governing
* rights and limitations under the License.
*
* Copyright (C) 2002-2004 Anders Bengtsson <ndrsbngtssn@yahoo.se>
* Copyright (C) 2001-2004 Jan Arne Petersen <jpetersen@uni-bonn.de>
* Copyright (C) 2002 Benoit Cerrina <b.cerrina@wanadoo.fr>
* Copyright (C) 2004-2007 Thomas E Enebo <enebo@acm.org>
* Copyright (C) 2004 Stefan Matthias Aust <sma@3plus4.de>
*
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package org.jruby.runtime;
import org.jruby.Ruby;
import org.jruby.runtime.backtrace.BacktraceElement;
import org.jruby.parser.StaticScope;
import org.jruby.runtime.builtin.IRubyObject;
import org.jruby.runtime.scope.ManyVarsDynamicScope;
/**
* Internal live representation of a block ({...} or do ... end).
*/
public class Binding {
/**
* frame of method which defined this block
*/
private final Frame frame;
private final BacktraceElement backtrace;
private Visibility visibility;
/**
* 'self' at point when the block is defined
*/
private IRubyObject self;
/**
* A reference to all variable values (and names) that are in-scope for this block.
*/
private final DynamicScope dynamicScope;
/**
* Binding-local scope for 1.9 mode.
*/
private DynamicScope evalScope;
/**
* Location of eval scope.
*
*
* Because bindings are usually cloned before used for eval, we indirect
* the reference of the eval scope through another Binding reference,
* allowing us to share the same eval scope across multiple cloned Binding
* instances.
*/
private Binding evalScopeBinding = this;
public Binding(IRubyObject self, Frame frame,
Visibility visibility, DynamicScope dynamicScope, BacktraceElement backtrace) {
this.self = self;
this.frame = frame;
this.visibility = visibility;
this.dynamicScope = dynamicScope;
this.backtrace = backtrace;
}
private Binding(IRubyObject self, Frame frame,
Visibility visibility, DynamicScope dynamicScope, BacktraceElement backtrace, DynamicScope dummyScope) {
this.self = self;
this.frame = frame;
this.visibility = visibility;
this.dynamicScope = dynamicScope;
this.backtrace = backtrace;
this.dummyScope = dummyScope;
}
public Binding(Frame frame, DynamicScope dynamicScope, BacktraceElement backtrace) {
this.self = frame.getSelf();
this.frame = frame;
this.visibility = frame.getVisibility();
this.dynamicScope = dynamicScope;
this.backtrace = backtrace;
}
private Binding(Binding other) {
this(other.self, other.frame, other.visibility, other.dynamicScope, other.backtrace, other.dummyScope);
}
/**
* Clone the binding, but maintain a reference to the original "eval
* binding" to continue sharing eval context.
*
* @return a new Binding with shared eval context
*/
public Binding cloneForEval() {
Binding clone = new Binding(this);
clone.evalScopeBinding = this;
return clone;
}
/**
* Clone the binding. The frame will be duplicated, and eval context will
* point to the new binding, but other fields will be copied as-is.
*
* @return a new cloned Binding
*/
public Binding clone() {
return new Binding(this);
}
public Visibility getVisibility() {
return visibility;
}
public void setVisibility(Visibility visibility) {
this.visibility = visibility;
}
public IRubyObject getSelf() {
return self;
}
public void setSelf(IRubyObject self) {
this.self = self;
}
/**
* Gets the dynamicVariables that are local to this block. Parent dynamic scopes are also
* accessible via the current dynamic scope.
*
* @return Returns all relevent variable scoping information
*/
public DynamicScope getDynamicScope() {
return dynamicScope;
}
private DynamicScope dummyScope;
public DynamicScope getDummyScope(StaticScope staticScope) {
if (dummyScope == null || dummyScope.getStaticScope() != staticScope) {
return dummyScope = DynamicScope.newDummyScope(staticScope, dynamicScope);
}
return dummyScope;
}
/**
* Gets the frame.
*
* @return Returns a RubyFrame
*/
public Frame getFrame() {
return frame;
}
public BacktraceElement getBacktrace() {
return backtrace;
}
public String getFile() {
return backtrace.filename;
}
public void setFile(String file) {
backtrace.filename = file;
}
public int getLine() {
return backtrace.line;
}
public void setLine(int line) {
backtrace.line = line;
}
public String getMethod() {
return backtrace.method;
}
public void setMethod(String method) {
backtrace.method = method;
}
public boolean equals(Object other) {
if(this == other) {
return true;
}
if(!(other instanceof Binding)) {
return false;
}
Binding bOther = (Binding)other;
return this.self == bOther.self &&
this.dynamicScope == bOther.dynamicScope;
}
// FIXME: This is because we clone the same explicit binding whenever we execute because both the captured Frame
// and the binding gets mutated during execution. This means that we cannot share the same instance across
// concurrent evals of the same binding. The mutated Frames I think can become new frames during execution and
// most of the binding clone can probably go away and we can push the values stored in a binding through the execution
// path.
public final DynamicScope getEvalScope(Ruby runtime) {
// We create one extra dynamicScope on a binding so that when we 'eval "b=1", binding' the
// 'b' will get put into this new dynamic scope. The original scope does not see the new
// 'b' and successive evals with this binding will. Note: This only happens for explicit
// bindings. Implicit bindings will always dispose of the scope they create.
// No eval scope set, so we create one
if (evalScopeBinding.evalScope == null) {
// bindings scopes must always be ManyVars scopes since evals can grow them
evalScopeBinding.evalScope = new ManyVarsDynamicScope(runtime.getStaticScopeFactory().newEvalScope(dynamicScope.getStaticScope()), dynamicScope);
}
return evalScopeBinding.evalScope;
}
}