ImageRefreshFix.java

package org.intellij.plugins.markdown.ui.preview.javafx;

import com.intellij.openapi.vfs.VirtualFile;
import com.intellij.openapi.vfs.VirtualFileManager;
import com.intellij.util.StringBuilderSpinAllocator;
import org.jetbrains.annotations.NotNull;

class ImageRefreshFix {
  private ImageRefreshFix() {
  }

  @NotNull
  static String setStamps(@NotNull String html) {
    final VirtualFileManager virtualFileManager = VirtualFileManager.getInstance();
    final String pattern = "<img src=\"file:";

    StringBuilder sb = StringBuilderSpinAllocator.alloc();
    try {
      int processedOffset = 0;
      while (true) {
        final int nextI = html.indexOf(pattern, processedOffset);
        if (nextI == -1) {
          break;
        }

        final int nextJ = html.indexOf('"', nextI + pattern.length());
        if (nextJ == -1) {
          return html;
        }

        sb.append(html, processedOffset, nextI + pattern.length());

        final String url = html.substring(nextI + pattern.length(), nextJ);
        sb.append(processUrl(virtualFileManager, url));
        sb.append('"');
        processedOffset = nextJ + 1;
      }

      if (processedOffset < html.length()) {
        sb.append(html, processedOffset, html.length());
      }
      return sb.toString();
    }
    finally {
      StringBuilderSpinAllocator.dispose(sb);
    }
  }

  @NotNull
  private static String processUrl(@NotNull VirtualFileManager virtualFileManager, @NotNull String url) {
    final VirtualFile virtualFile = virtualFileManager.findFileByUrl("file://" + url);
    if (virtualFile == null) {
      return url;
    }
    return url + "?stamp=" + virtualFile.getModificationStamp();
  }
}