/*
***** 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.
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* Copyright (C) 2006-2007 Thomas E Enebo <enebo@acm.org>
*
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* or the GNU Lesser General Public License Version 2.1 or later (the "LGPL"),
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package org.jruby.parser;
import java.io.Serializable;
import java.util.Arrays;
import org.jruby.RubyModule;
import org.jruby.RubyObject;
import org.jruby.ast.AssignableNode;
import org.jruby.ast.DAsgnNode;
import org.jruby.ast.DVarNode;
import org.jruby.ast.LocalAsgnNode;
import org.jruby.ast.LocalVarNode;
import org.jruby.ast.Node;
import org.jruby.ast.VCallNode;
import org.jruby.ir.IRScope;
import org.jruby.ir.IRScopeType;
import org.jruby.lexer.yacc.ISourcePosition;
import org.jruby.runtime.Arity;
import org.jruby.runtime.DynamicScope;
import org.jruby.runtime.builtin.IRubyObject;
import org.jruby.runtime.scope.DummyDynamicScope;
/**
* StaticScope represents lexical scoping of variables and module/class constants.
*
* At a very high level every scopes enclosing scope contains variables in the next outer
* lexical layer. The enclosing scopes variables may or may not be reachable depending
* on the scoping rules for variables (governed by BlockStaticScope and LocalStaticScope).
*
* StaticScope also keeps track of current module/class that is in scope. previousCRefScope
* will point to the previous scope of the enclosing module/class (cref).
*
*/
public class StaticScope implements Serializable {
private static final long serialVersionUID = 3423852552352498148L;
// Next immediate scope. Variable and constant scoping rules make use of this variable
// in different ways.
final protected StaticScope enclosingScope;
// Live reference to module
private transient RubyModule cref = null;
// Next CRef down the lexical structure
private StaticScope previousCRefScope = null;
// Our name holder (offsets are assigned as variables are added
private String[] variableNames;
// number of variables in this scope representing required arguments
private int requiredArgs = 0;
// number of variables in this scope representing optional arguments
private int optionalArgs = 0;
// index of variable that represents a "rest" arg
private int restArg = -1;
private DynamicScope dummyScope;
protected IRScopeType scopeType;
private static final String[] NO_NAMES = new String[0];
private Type type;
private boolean isBlockOrEval;
private boolean isArgumentScope; // Is this block and argument scope of a define_method (for the purposes of zsuper).
private int scopeId;
private IRScope irScope; // Method/Closure that this static scope corresponds to
public enum Type {
LOCAL, BLOCK, EVAL;
public static Type fromOrdinal(int value) {
return value < 0 || value >= values().length ? null : values()[value];
}
}
/**
* Construct a new static scope.
*
* @param type the type of scope
* @param enclosingScope the lexically containing scope.
*/
protected StaticScope(Type type, StaticScope enclosingScope) {
this(type, enclosingScope, NO_NAMES);
}
/**
* Construct a new static scope. The array of strings should all be the
* interned versions, since several other optimizations depend on being
* able to do object equality checks.
*
* @param type the type of scope
* @param enclosingScope the lexically containing scope.
* @param names The list of interned String variable names.
*/
protected StaticScope(Type type, StaticScope enclosingScope, String[] names) {
assert names != null : "names is not null";
assert namesAreInterned(names);
this.enclosingScope = enclosingScope;
this.variableNames = names;
this.type = type;
this.irScope = null;
this.isBlockOrEval = (type != Type.LOCAL);
this.isArgumentScope = !isBlockOrEval;
}
public IRScope getIRScope() {
return irScope;
}
public int getScopeId() {
return scopeId;
}
public IRScopeType getScopeType() {
return scopeType;
}
public void setScopeType(IRScopeType scopeType) {
this.scopeType = scopeType;
}
public void setIRScope(IRScope irScope, boolean isForLoopBody) {
if (!isForLoopBody) {
this.irScope = irScope;
}
this.scopeId = irScope.getScopeId();
this.scopeType = irScope.getScopeType();
}
public void setIRScope(IRScope irScope) {
setIRScope(irScope, false);
}
/**
* Check that all strings in the given array are the interned versions.
*
* @param names The array of strings
* @return true if they are all interned, false otherwise
*/
private static boolean namesAreInterned(String[] names) {
for (String name : names) {
// Note that this object equality check is intentional, to ensure
// the string and its interned version are the same object.
if (name != name.intern()) return false;
}
return true;
}
/**
* Add a new variable to this (current) scope unless it is already defined in the
* current scope.
*
* @param name of new variable
* @return index+depth merged location of scope
*/
public int addVariableThisScope(String name) {
// Ignore duplicate "_" args in blocks
// (duplicate _ args are named "_$0")
// Dont allocate slots for them.
if (name.equals("_$0")) {
return -1;
}
int slot = exists(name);
if (slot >= 0) return slot;
// This is perhaps innefficient timewise? Optimal spacewise
growVariableNames(name);
// Returns slot of variable
return variableNames.length - 1;
}
/**
* Add a new variable to this (current) scope unless it is already defined in any
* reachable scope.
*
* @param name of new variable
* @return index+depth merged location of scope
*/
public int addVariable(String name) {
int slot = isDefined(name);
if (slot >= 0) return slot;
// This is perhaps innefficient timewise? Optimal spacewise
growVariableNames(name);
// Returns slot of variable
return variableNames.length - 1;
}
public String[] getVariables() {
return variableNames;
}
public int getNumberOfVariables() {
return irScope == null ? variableNames.length : irScope.getUsedVariablesCount();
}
public void setVariables(String[] names) {
assert names != null : "names is not null";
variableNames = new String[names.length];
System.arraycopy(names, 0, variableNames, 0, names.length);
}
/* Note: Only used by compiler until it can use getConstant again or use some other refactoring */
public IRubyObject getConstantWithConstMissing(String internedName) {
IRubyObject result = getConstantInner(internedName);
// If we could not find the constant from cref..then try getting from inheritence hierarchy
return result == null ? cref.getConstant(internedName) : result;
}
public boolean isConstantDefined(String internedName) {
return getConstant(internedName) != null;
}
public IRubyObject getConstant(String internedName) {
IRubyObject result = getConstantInner(internedName);
// If we could not find the constant from cref..then try getting from inheritence hierarchy
return result == null ? cref.getConstantNoConstMissing(internedName) : result;
}
public IRubyObject getConstantInner(String internedName) {
IRubyObject result = cref.fetchConstant(internedName);
if (result != null) {
return result == RubyObject.UNDEF ? cref.resolveUndefConstant(internedName) : result;
}
return previousCRefScope == null ? null : previousCRefScope.getConstantInnerNoObject(internedName);
}
private IRubyObject getConstantInnerNoObject(String internedName) {
if (previousCRefScope == null) return null;
return getConstantInner(internedName);
}
public IRubyObject setConstant(String internedName, IRubyObject result) {
RubyModule module;
if ((module = getModule()) != null) {
module.setConstant(internedName, result);
return result;
}
// TODO: wire into new exception handling mechanism
throw result.getRuntime().newTypeError("no class/module to define constant");
}
/**
* Next outer most scope in list of scopes. An enclosing scope may have no direct scoping
* relationship to its child. If I am in a localScope and then I enter something which
* creates another localScope the enclosing scope will be the first scope, but there are
* no valid scoping relationships between the two. Methods which walk the enclosing scopes
* are responsible for enforcing appropriate scoping relationships.
*
* @return the parent scope
*/
public StaticScope getEnclosingScope() {
return enclosingScope;
}
/**
* Does the variable exist?
*
* @param name of the variable to find
* @return index of variable or -1 if it does not exist
*/
public int exists(String name) {
return findVariableName(name);
}
private int findVariableName(String name) {
for (int i = 0; i < variableNames.length; i++) {
if (name == variableNames[i]) return i;
}
return -1;
}
/**
* Is this name in the visible to the current scope
*
* @param name to be looked for
* @return a location where the left-most 16 bits of number of scopes down it is and the
* right-most 16 bits represents its index in that scope
*/
public int isDefined(String name) {
return isDefined(name, 0);
}
/**
* Make a DASgn or LocalAsgn node based on scope logic
*
* @param position
* @param name
* @param value
* @return
*/
public AssignableNode assign(ISourcePosition position, String name, Node value) {
return assign(position, name, value, this, 0);
}
/**
* Get all visible variables that we can see from this scope that have been assigned
* (e.g. seen so far)
*
* @return a list of all names (sans $~ and $_ which are special names)
*/
public String[] getAllNamesInScope() {
String[] names = getVariables();
if (isBlockOrEval) {
String[] ourVariables = names;
String[] variables = enclosingScope.getAllNamesInScope();
// we know variables cannot be null since this IRStaticScope always returns a non-null array
names = new String[variables.length + ourVariables.length];
System.arraycopy(variables, 0, names, 0, variables.length);
System.arraycopy(ourVariables, 0, names, variables.length, ourVariables.length);
}
return names;
}
public int isDefined(String name, int depth) {
if (isBlockOrEval) {
int slot = exists(name);
if (slot >= 0) return (depth << 16) | slot;
return enclosingScope.isDefined(name, depth + 1);
} else {
return (depth << 16) | exists(name);
}
}
public AssignableNode addAssign(ISourcePosition position, String name, Node value) {
int slot = addVariable(name);
// No bit math to store level since we know level is zero for this case
return new DAsgnNode(position, name, slot, value);
}
public AssignableNode assign(ISourcePosition position, String name, Node value,
StaticScope topScope, int depth) {
int slot = exists(name);
// We can assign if we already have variable of that name here or we are the only
// scope in the chain (which Local scopes always are).
if (slot >= 0) {
return isBlockOrEval ? new DAsgnNode(position, name, ((depth << 16) | slot), value)
: new LocalAsgnNode(position, name, ((depth << 16) | slot), value);
} else if (!isBlockOrEval && (topScope == this)) {
slot = addVariable(name);
return new LocalAsgnNode(position, name, slot, value);
}
// If we are not a block-scope and we go there, we know that 'topScope' is a block scope
// because a local scope cannot be within a local scope
// If topScope was itself it would have created a LocalAsgnNode above.
return isBlockOrEval ? enclosingScope.assign(position, name, value, topScope, depth + 1)
: topScope.addAssign(position, name, value);
}
public Node declare(ISourcePosition position, String name, int depth) {
int slot = exists(name);
if (slot >= 0) {
return isBlockOrEval ? new DVarNode(position, ((depth << 16) | slot), name) : new LocalVarNode(position, ((depth << 16) | slot), name);
}
return isBlockOrEval ? enclosingScope.declare(position, name, depth + 1) : new VCallNode(position, name);
}
/**
* Make a DVar or LocalVar node based on scoping logic
*
* @param position the location that in the source that the new node will come from
* @param name of the variable to be created is named
* @return a DVarNode or LocalVarNode
*/
public Node declare(ISourcePosition position, String name) {
return declare(position, name, 0);
}
/**
* Gets the Local Scope relative to the current Scope. For LocalScopes this will be itself.
* Blocks will contain the LocalScope it contains.
*
* @return localScope
*/
public StaticScope getLocalScope() {
return (type != Type.BLOCK) ? this : enclosingScope.getLocalScope();
}
/**
* Get the live CRef module associated with this scope.
*
* @return the live module
*/
public RubyModule getModule() {
return cref;
}
public StaticScope getPreviousCRefScope() {
return previousCRefScope;
}
public void setPreviousCRefScope(StaticScope crefScope) {
this.previousCRefScope = crefScope;
}
public void setModule(RubyModule module) {
this.cref = module;
for (StaticScope scope = getEnclosingScope(); scope != null; scope = scope.getEnclosingScope()) {
if (scope.cref != null) {
previousCRefScope = scope;
return;
}
}
}
/**
* Update current scoping structure to populate with proper cref scoping values. This should
* be called at any point when you reference a scope for the first time. For the interpreter
* this is done in a small number of places (defnNode, defsNode, and getBlock). The compiler
* does this in the same places.
*
* @return the current cref, though this is largely an implementation detail
*/
public RubyModule determineModule() {
if (cref == null) {
cref = getEnclosingScope().determineModule();
assert cref != null : "CRef is always created before determine happens";
previousCRefScope = getEnclosingScope().previousCRefScope;
}
return cref;
}
public int getOptionalArgs() {
return optionalArgs;
}
public int getRequiredArgs() {
return requiredArgs;
}
public void setRequiredArgs(int requiredArgs) {
this.requiredArgs = requiredArgs;
}
public int getRestArg() {
return restArg;
}
public void setRestArg(int restArg) {
this.restArg = restArg;
}
public boolean isBlockScope() {
return isBlockOrEval;
}
/**
* Argument scopes represent scopes which contain arguments for zsuper. All LocalStaticScopes
* are argument scopes and BlockStaticScopes can be when they are used by define_method.
*/
public boolean isArgumentScope() {
return isArgumentScope;
}
public void makeArgumentScope() {
this.isArgumentScope = true;
}
public Arity getArity() {
if (optionalArgs > 0) {
if (restArg >= 0) {
return Arity.optional();
}
return Arity.required(requiredArgs);
} else {
if (restArg >= 0) {
return Arity.optional();
}
return Arity.fixed(requiredArgs);
}
}
public void setArities(int required, int optional, int rest) {
this.requiredArgs = required;
this.optionalArgs = optional;
this.restArg = rest;
}
public DynamicScope getDummyScope() {
return dummyScope == null ? dummyScope = new DummyDynamicScope(this) : dummyScope;
}
private void growVariableNames(String name) {
String[] newVariableNames = new String[variableNames.length + 1];
System.arraycopy(variableNames, 0, newVariableNames, 0, variableNames.length);
variableNames = newVariableNames;
variableNames[variableNames.length - 1] = name;
}
@Override
public String toString() {
// FIXME: Do we need to persist cref as well?
return "StaticScope(" + type + "):" + Arrays.toString(variableNames);
}
public Type getType() {
return type;
}
public StaticScope duplicate() {
StaticScope dupe = new StaticScope(type, enclosingScope, variableNames == null ? NO_NAMES : variableNames);
// irScope is not guaranteed to be set onto StaticScope until it is executed for the first time.
// We can call duplicate before its first execution.
if (irScope != null) dupe.setIRScope(irScope);
dupe.setScopeType(scopeType);
dupe.setPreviousCRefScope(previousCRefScope);
dupe.setModule(cref);
return dupe;
}
}