xml/xml-psi-impl/src/com/intellij/xml/util/InclusionProvider.java

/*
 * Copyright 2000-2014 JetBrains s.r.o.
 *
 * 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.intellij.xml.util;

import com.intellij.openapi.util.NullableComputable;
import com.intellij.openapi.util.RecursionManager;
import com.intellij.psi.PsiElement;
import com.intellij.psi.util.CachedValueProvider;
import com.intellij.psi.util.CachedValuesManager;
import com.intellij.psi.util.PsiModificationTracker;
import com.intellij.psi.xml.XmlDocument;
import com.intellij.psi.xml.XmlFile;
import com.intellij.psi.xml.XmlTag;
import com.intellij.util.xmlb.JDOMXIncluder;
import org.jetbrains.annotations.NotNull;
import org.jetbrains.annotations.Nullable;

import java.util.regex.Matcher;

/**
* @author peter
*/
class InclusionProvider implements CachedValueProvider<PsiElement[]> {
  private final XmlTag myXincludeTag;

  public InclusionProvider(XmlTag xincludeTag) {
    myXincludeTag = xincludeTag;
  }

  @NotNull
  public static PsiElement[] getIncludedTags(XmlTag xincludeTag) {
    if (XmlUtil.isStubBuilding()) return PsiElement.EMPTY_ARRAY;
    return CachedValuesManager.getCachedValue(xincludeTag, new InclusionProvider(xincludeTag));
  }

  @Override
  public Result<PsiElement[]> compute() {
    PsiElement[] result = RecursionManager.doPreventingRecursion(myXincludeTag, true, new NullableComputable<PsiElement[]>() {
      @Override
      public PsiElement[] compute() {
        return computeInclusion(myXincludeTag);
      }
    });
    return Result.create(result == null ? PsiElement.EMPTY_ARRAY : result, PsiModificationTracker.OUT_OF_CODE_BLOCK_MODIFICATION_COUNT);
  }

  private static XmlTag[] extractXpointer(@NotNull XmlTag rootTag, @Nullable final String xpointer) {
    if (xpointer != null) {
      Matcher matcher = JDOMXIncluder.XPOINTER_PATTERN.matcher(xpointer);
      if (matcher.matches()) {
        String pointer = matcher.group(1);
        matcher = JDOMXIncluder.CHILDREN_PATTERN.matcher(pointer);
        if (matcher.matches() && matcher.group(1).equals(rootTag.getName())) {
          return rootTag.getSubTags();
        }
      }
    }

    return new XmlTag[]{rootTag};
  }

  @Nullable
  private static PsiElement[] computeInclusion(final XmlTag xincludeTag) {
    final XmlFile included = XmlIncludeHandler.resolveXIncludeFile(xincludeTag);
    final XmlDocument document = included != null ? included.getDocument() : null;
    final XmlTag rootTag = document != null ? document.getRootTag() : null;
    if (rootTag != null) {
      final String xpointer = xincludeTag.getAttributeValue("xpointer", XmlPsiUtil.XINCLUDE_URI);
      final XmlTag[] includeTag = extractXpointer(rootTag, xpointer);
      PsiElement[] result = new PsiElement[includeTag.length];
      for (int i = 0; i < includeTag.length; i++) {
        result[i] = new IncludedXmlTag(includeTag[i], xincludeTag.getParentTag());
      }
      return result;
    }

    return null;
  }

}