com.google.javascript.jscomp.TypedVar Maven / Gradle / Ivy

/*
 * Copyright 2015 The Closure Compiler Authors.
 *
 * Licensed 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 com.google.javascript.jscomp;

import com.google.javascript.rhino.ErrorReporter;
import com.google.javascript.rhino.Node;
import com.google.javascript.rhino.jstype.JSType;
import com.google.javascript.rhino.jstype.StaticTypedRef;
import com.google.javascript.rhino.jstype.StaticTypedSlot;

/**
 * {@link AbstractVar} subclass for use with {@link TypedScope}.
 *
 * Note that this class inherits its {@link #equals} and {@link #hashCode} implementations from
 * {@link ScopedName}, which does not include any type information. This is necessary because {@code
 * Var}-keyed maps are used across multiple top scopes, but it comes with the caveat that if {@code
 * TypedVar} instances are stored in a set, the type information is at risk of disappearing if an
 * untyped (or differently typed) var is added for the same symbol.
 */
public class TypedVar extends AbstractVar
    implements StaticTypedSlot, StaticTypedRef {

  private JSType type;
  // The next two fields and the associated methods are only used by
  // TypeInference.java. Maybe there is a way to avoid having them in all typed variable instances.
  private boolean markedEscaped = false;
  private boolean markedAssignedExactlyOnce = false;

  /**
   * Whether the variable's type has been inferred or is declared. An inferred
   * type may change over time (as more code is discovered), whereas a
   * declared type is a static contract that must be matched.
   */
  private final boolean typeInferred;

  TypedVar(boolean inferred, String name, Node nameNode, JSType type,
      TypedScope scope, int index, CompilerInput input) {
    super(name, nameNode, scope, index, input);
    this.type = type;
    this.typeInferred = inferred;
  }

  /**
   * Gets this variable's type. To know whether this type has been inferred,
   * see {@code #isTypeInferred()}.
   */
  @Override
  public JSType getType() {
    return type;
  }

  void setType(JSType type) {
    this.type = type;
  }

  void resolveType(ErrorReporter errorReporter) {
    if (type != null) {
      this.type = type.resolve(errorReporter);
    }
  }

  /**
   * Returns whether this variable's type is inferred. To get the variable's
   * type, see {@link #getType()}.
   */
  @Override
  public boolean isTypeInferred() {
    return typeInferred;
  }

  public String getInputName() {
    if (input == null) {
      return "";
    }
    return input.getName();
  }

  @Override
  public String toString() {
    return "Var " + name + "{" + type + "}";
  }

  void markEscaped() {
    markedEscaped = true;
  }

  boolean isMarkedEscaped() {
    return markedEscaped;
  }

  void markAssignedExactlyOnce() {
    markedAssignedExactlyOnce = true;
  }

  boolean isMarkedAssignedExactlyOnce() {
    return markedAssignedExactlyOnce;
  }
}