AnnotatePreviousRevisionAction.java

package com.intellij.openapi.vcs.actions;

import com.intellij.icons.AllIcons;
import com.intellij.openapi.actionSystem.AnActionEvent;
import com.intellij.openapi.localVcs.UpToDateLineNumberProvider;
import com.intellij.openapi.vcs.AbstractVcs;
import com.intellij.openapi.vcs.annotate.FileAnnotation;
import com.intellij.openapi.vcs.history.VcsFileRevision;
import org.jetbrains.annotations.NotNull;
import org.jetbrains.annotations.Nullable;

class AnnotatePreviousRevisionAction extends AnnotateRevisionAction {
  @Nullable private final FileAnnotation.PreviousFileRevisionProvider myProvider;

  public AnnotatePreviousRevisionAction(@NotNull FileAnnotation annotation, @NotNull AbstractVcs vcs) {
    super("Annotate Previous Revision", "Annotate successor of selected revision in new tab", AllIcons.Actions.Annotate,
          annotation, vcs);
    myProvider = annotation.getPreviousFileRevisionProvider();
  }

  @Override
  public void update(@NotNull AnActionEvent e) {
    if (myProvider == null) {
      e.getPresentation().setEnabledAndVisible(false);
      return;
    }
    super.update(e);
  }

  @Nullable
  @Override
  protected VcsFileRevision getRevision(int lineNumber) {
    assert myProvider != null;

    if (lineNumber == UpToDateLineNumberProvider.ABSENT_LINE_NUMBER) {
      return myProvider.getLastRevision();
    }
    else {
      if (lineNumber < 0 || lineNumber >= myAnnotation.getLineCount()) return null;
      return myProvider.getPreviousRevision(lineNumber);
    }
  }
}