/*
* Copyright 2000-2016 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.util.gist;
import com.intellij.psi.PsiFile;
import org.jetbrains.annotations.NotNull;
/**
* Calculates some data based on {@link PsiFile} content, persists it between IDE restarts,
* and updates it when the content is changed. The data is calculated lazily, when needed.<p/>
*
* Obtained using {@link GistManager#newPsiFileGist}.<p/>
*
* The difference to {@link VirtualFileGist} is that PSI content is used here. So if an uncommitted document is saved onto disk,
* this class will use the last committed content of the PSI file, while {@link VirtualFileGist} will use the saved virtual file content.<p/>
*
* Please note that VirtualFileGist is used inside, so using PsiFileGist has the same performance implications (see {@link VirtualFileGist} documentation).
*
* @since 171.*
* @author peter
*/
public interface PsiFileGist<Data> {
/**
* Calculate or get the cached data by the current PSI content.
*/
Data getFileData(@NotNull PsiFile file);
}