UnreferencedSymbolFilter.java

/*
 * Copyright (c) 2014 Patrick Scheibe
 * Permission is hereby granted, free of charge, to any person obtaining a copy
 * of this software and associated documentation files (the "Software"), to deal
 * in the Software without restriction, including without limitation the rights
 * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
 * copies of the Software, and to permit persons to whom the Software is
 * furnished to do so, subject to the following conditions:
 *
 * The above copyright notice and this permission notice shall be included in
 * all copies or substantial portions of the Software.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
 * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
 * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
 * THE SOFTWARE.
 */

package de.halirutan.mathematica.parsing.psi.util;

import com.intellij.psi.PsiElement;
import com.intellij.psi.PsiFile;
import com.intellij.psi.util.PsiElementFilter;
import de.halirutan.mathematica.parsing.psi.api.Symbol;
import de.halirutan.mathematica.parsing.psi.api.assignment.Set;
import de.halirutan.mathematica.parsing.psi.api.assignment.SetDelayed;

import java.util.List;

/**
 * @author patrick (1/6/14)
 */
public class UnreferencedSymbolFilter implements PsiElementFilter {
  public static final int MAX_UPWARD_STEPS = 3;

  @Override
  public boolean isAccepted(PsiElement element) {
    if (element instanceof Symbol) {
      Symbol symbol = (Symbol) element;
      PsiElement parent = symbol.getParent();
      int iter = 0;
      while (parent != null && ++iter != MAX_UPWARD_STEPS && !(parent instanceof PsiFile)) {
        if (parent instanceof Set || parent instanceof SetDelayed) {
          final List<Symbol> assignmentSymbols = MathematicaPsiUtilities.getAssignmentSymbols(parent);
          return assignmentSymbols != null && assignmentSymbols.contains(element);
        }
        parent = parent.getParent();
      }

    }
    return false;
  }
}