platform/vcs-api/src/com/intellij/openapi/vcs/vfs/ContentRevisionVirtualFile.java

/*
 * Copyright 2000-2009 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.openapi.vcs.vfs;

import com.intellij.openapi.application.ApplicationManager;
import com.intellij.openapi.progress.ProcessCanceledException;
import com.intellij.openapi.ui.Messages;
import com.intellij.openapi.vcs.VcsBundle;
import com.intellij.openapi.vcs.VcsException;
import com.intellij.openapi.vcs.changes.ContentRevision;
import com.intellij.openapi.vfs.CharsetToolkit;
import com.intellij.util.ArrayUtil;
import com.intellij.util.containers.WeakHashMap;
import org.jetbrains.annotations.NotNull;

import java.io.IOException;
import java.nio.ByteBuffer;

/**
 * @author yole
 */
public class ContentRevisionVirtualFile extends AbstractVcsVirtualFile {
  private final ContentRevision myContentRevision;
  private byte[] myContent;
  private boolean myContentLoadFailed;

  private static final WeakHashMap<ContentRevision, ContentRevisionVirtualFile> ourMap = new WeakHashMap<ContentRevision, ContentRevisionVirtualFile>();

  public static ContentRevisionVirtualFile create(ContentRevision contentRevision) {
    synchronized(ourMap) {
      ContentRevisionVirtualFile revisionVirtualFile = ourMap.get(contentRevision);
      if (revisionVirtualFile == null) {
        revisionVirtualFile = new ContentRevisionVirtualFile(contentRevision);
        ourMap.put(contentRevision, revisionVirtualFile);
      }
      return revisionVirtualFile;
    }
  }

  private ContentRevisionVirtualFile(ContentRevision contentRevision) {
    super(contentRevision.getFile().getPath(), VcsFileSystem.getInstance());
    myContentRevision = contentRevision;
    setCharset(CharsetToolkit.UTF8_CHARSET);
  }

  public boolean isDirectory() {
    return false;
  }

  @NotNull
  public byte[] contentsToByteArray() throws IOException {
    if (myContentLoadFailed || myProcessingBeforeContentsChange) {
      return ArrayUtil.EMPTY_BYTE_ARRAY;
    }
    if (myContent == null) {
      loadContent();
    }
    return myContent;
  }

  private void loadContent() {
    final VcsFileSystem vcsFileSystem = ((VcsFileSystem)getFileSystem());

    try {
      final String content = myContentRevision.getContent();
      if (content == null) {
        throw new VcsException("Could not load content");
      }
      fireBeforeContentsChange();

      myModificationStamp++;
      setRevision(myContentRevision.getRevisionNumber().asString());
      myContent = content.getBytes(getCharset());
      ApplicationManager.getApplication().runWriteAction(new Runnable() {
        public void run() {
          vcsFileSystem.fireContentsChanged(this, ContentRevisionVirtualFile.this, 0);
        }
      });

    }
    catch (VcsException e) {
      myContentLoadFailed = true;
      ApplicationManager.getApplication().runWriteAction(new Runnable() {
        public void run() {
          vcsFileSystem.fireBeforeFileDeletion(this, ContentRevisionVirtualFile.this);
        }
      });
      myContent = ArrayUtil.EMPTY_BYTE_ARRAY;
      setRevision("0");

      Messages.showMessageDialog(
        VcsBundle.message("message.text.could.not.load.virtual.file.content", getPresentableUrl(), e.getLocalizedMessage()),
                                 VcsBundle.message("message.title.could.not.load.content"),
                                 Messages.getInformationIcon());

      ApplicationManager.getApplication().runWriteAction(new Runnable() {
        public void run() {
          vcsFileSystem.fireFileDeleted(this, ContentRevisionVirtualFile.this, getName(), getParent());
        }
      });

    }
    catch (ProcessCanceledException ex) {
      myContent = ArrayUtil.EMPTY_BYTE_ARRAY;
    }
  }
}