/*
* Licensed to Elasticsearch under one or more contributor
* license agreements. See the NOTICE file distributed with
* this work for additional information regarding copyright
* ownership. Elasticsearch licenses this file to you under
* the Apache License, Version 2.0 (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.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing,
* software distributed under the License is distributed on an
* "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
* KIND, either express or implied. See the License for the
* specific language governing permissions and limitations
* under the License.
*/
package org.elasticsearch.painless;
import org.elasticsearch.painless.Definition.Method;
import org.elasticsearch.painless.Definition.MethodKey;
import org.elasticsearch.painless.Definition.Type;
import org.elasticsearch.painless.ScriptInterface.MethodArgument;
import java.util.Arrays;
import java.util.Collection;
import java.util.Collections;
import java.util.HashMap;
import java.util.HashSet;
import java.util.List;
import java.util.Map;
import java.util.Set;
/**
* Tracks user defined methods and variables across compilation phases.
*/
public final class Locals {
/** Reserved word: loop counter */
public static final String LOOP = "#loop";
/** Reserved word: unused */
public static final String THIS = "#this";
/** Set of reserved keywords. */
public static final Set<String> KEYWORDS = Collections.unmodifiableSet(new HashSet<>(Arrays.asList(
THIS, LOOP
)));
/** Creates a new local variable scope (e.g. loop) inside the current scope */
public static Locals newLocalScope(Locals currentScope) {
return new Locals(currentScope);
}
/**
* Creates a new lambda scope inside the current scope
* <p>
* This is just like {@link #newFunctionScope}, except the captured parameters are made read-only.
*/
public static Locals newLambdaScope(Locals programScope, Type returnType, List<Parameter> parameters,
int captureCount, int maxLoopCounter) {
Locals locals = new Locals(programScope, programScope.definition, returnType, KEYWORDS);
for (int i = 0; i < parameters.size(); i++) {
Parameter parameter = parameters.get(i);
// TODO: allow non-captures to be r/w:
// boolean isCapture = i < captureCount;
// currently, this cannot be allowed, as we swap in real types,
// but that can prevent a store of a different type...
boolean isCapture = true;
locals.addVariable(parameter.location, parameter.type, parameter.name, isCapture);
}
// Loop counter to catch infinite loops. Internal use only.
if (maxLoopCounter > 0) {
locals.defineVariable(null, Definition.INT_TYPE, LOOP, true);
}
return locals;
}
/** Creates a new function scope inside the current scope */
public static Locals newFunctionScope(Locals programScope, Type returnType, List<Parameter> parameters, int maxLoopCounter) {
Locals locals = new Locals(programScope, programScope.definition, returnType, KEYWORDS);
for (Parameter parameter : parameters) {
locals.addVariable(parameter.location, parameter.type, parameter.name, false);
}
// Loop counter to catch infinite loops. Internal use only.
if (maxLoopCounter > 0) {
locals.defineVariable(null, Definition.INT_TYPE, LOOP, true);
}
return locals;
}
/** Creates a new main method scope */
public static Locals newMainMethodScope(ScriptInterface scriptInterface, Locals programScope, int maxLoopCounter) {
Locals locals = new Locals(programScope, programScope.definition,
scriptInterface.getExecuteMethodReturnType(), KEYWORDS);
// This reference. Internal use only.
locals.defineVariable(null, programScope.definition.getType("Object"), THIS, true);
// Method arguments
for (MethodArgument arg : scriptInterface.getExecuteArguments()) {
locals.defineVariable(null, arg.getType(), arg.getName(), true);
}
// Loop counter to catch infinite loops. Internal use only.
if (maxLoopCounter > 0) {
locals.defineVariable(null, Definition.INT_TYPE, LOOP, true);
}
return locals;
}
/** Creates a new program scope: the list of methods. It is the parent for all methods */
public static Locals newProgramScope(Definition definition, Collection<Method> methods) {
Locals locals = new Locals(null, definition, null, null);
for (Method method : methods) {
locals.addMethod(method);
}
return locals;
}
/** Checks if a variable exists or not, in this scope or any parents. */
public boolean hasVariable(String name) {
Variable variable = lookupVariable(null, name);
if (variable != null) {
return true;
}
if (parent != null) {
return parent.hasVariable(name);
}
return false;
}
/** Accesses a variable. This will throw IAE if the variable does not exist */
public Variable getVariable(Location location, String name) {
Variable variable = lookupVariable(location, name);
if (variable != null) {
return variable;
}
if (parent != null) {
return parent.getVariable(location, name);
}
throw location.createError(new IllegalArgumentException("Variable [" + name + "] is not defined."));
}
/** Looks up a method. Returns null if the method does not exist. */
public Method getMethod(MethodKey key) {
Method method = lookupMethod(key);
if (method != null) {
return method;
}
if (parent != null) {
return parent.getMethod(key);
}
return null;
}
/** Creates a new variable. Throws IAE if the variable has already been defined (even in a parent) or reserved. */
public Variable addVariable(Location location, Type type, String name, boolean readonly) {
if (hasVariable(name)) {
throw location.createError(new IllegalArgumentException("Variable [" + name + "] is already defined."));
}
if (keywords.contains(name)) {
throw location.createError(new IllegalArgumentException("Variable [" + name + "] is reserved."));
}
return defineVariable(location, type, name, readonly);
}
/** Return type of this scope (e.g. int, if inside a function that returns int) */
public Type getReturnType() {
return returnType;
}
/** Returns the top-level program scope. */
public Locals getProgramScope() {
Locals locals = this;
while (locals.getParent() != null) {
locals = locals.getParent();
}
return locals;
}
/** Whitelist against which this script is being compiled. */
public Definition getDefinition() {
return definition;
}
///// private impl
/** Whitelist against which thhis script is being compiled. */
private final Definition definition;
// parent scope
private final Locals parent;
// return type of this scope
private final Type returnType;
// keywords for this scope
private final Set<String> keywords;
// next slot number to assign
private int nextSlotNumber;
// variable name -> variable
private Map<String,Variable> variables;
// method name+arity -> methods
private Map<MethodKey,Method> methods;
/**
* Create a new Locals
*/
private Locals(Locals parent) {
this(parent, parent.definition, parent.returnType, parent.keywords);
}
/**
* Create a new Locals with specified return type
*/
private Locals(Locals parent, Definition definition, Type returnType, Set<String> keywords) {
this.parent = parent;
this.definition = definition;
this.returnType = returnType;
this.keywords = keywords;
if (parent == null) {
this.nextSlotNumber = 0;
} else {
this.nextSlotNumber = parent.getNextSlot();
}
}
/** Returns the parent scope */
private Locals getParent() {
return parent;
}
/** Looks up a variable at this scope only. Returns null if the variable does not exist. */
private Variable lookupVariable(Location location, String name) {
if (variables == null) {
return null;
}
return variables.get(name);
}
/** Looks up a method at this scope only. Returns null if the method does not exist. */
private Method lookupMethod(MethodKey key) {
if (methods == null) {
return null;
}
return methods.get(key);
}
/** Defines a variable at this scope internally. */
private Variable defineVariable(Location location, Type type, String name, boolean readonly) {
if (variables == null) {
variables = new HashMap<>();
}
Variable variable = new Variable(location, name, type, getNextSlot(), readonly);
variables.put(name, variable); // TODO: check result
nextSlotNumber += type.type.getSize();
return variable;
}
private void addMethod(Method method) {
if (methods == null) {
methods = new HashMap<>();
}
methods.put(new MethodKey(method.name, method.arguments.size()), method);
// TODO: check result
}
private int getNextSlot() {
return nextSlotNumber;
}
public static final class Variable {
public final Location location;
public final String name;
public final Type type;
public final boolean readonly;
private final int slot;
public Variable(Location location, String name, Type type, int slot, boolean readonly) {
this.location = location;
this.name = name;
this.type = type;
this.slot = slot;
this.readonly = readonly;
}
public int getSlot() {
return slot;
}
@Override
public String toString() {
StringBuilder b = new StringBuilder();
b.append("Variable[type=").append(type);
b.append(",name=").append(name);
b.append(",slot=").append(slot);
if (readonly) {
b.append(",readonly");
}
b.append(']');
return b.toString();
}
}
public static final class Parameter {
public final Location location;
public final String name;
public final Type type;
public Parameter(Location location, String name, Type type) {
this.location = location;
this.name = name;
this.type = type;
}
}
}