MarkdownParser.java

package com.expensify.livemarkdown;

import static com.expensify.livemarkdown.RangeSplitter.splitRangesOnEmojis;

import androidx.annotation.NonNull;

import com.facebook.react.bridge.ReactContext;
import com.facebook.react.util.RNLog;
import com.facebook.soloader.SoLoader;
import com.facebook.systrace.Systrace;

import org.json.JSONArray;
import org.json.JSONException;
import org.json.JSONObject;

import java.util.ArrayList;
import java.util.Collections;
import java.util.LinkedList;
import java.util.List;

public class MarkdownParser {
  static {
    SoLoader.loadLibrary("livemarkdown");
  }

  private final @NonNull ReactContext mReactContext;
  private String mPrevText;
  private int mPrevParserId;
  private List<MarkdownRange> mPrevMarkdownRanges;

  public MarkdownParser(@NonNull ReactContext reactContext) {
    mReactContext = reactContext;
  }

  private native String nativeParse(@NonNull String text, int parserId);

  private List<MarkdownRange> parseRanges(String rangesJSON, String innerText) {
    List<MarkdownRange> markdownRanges = new ArrayList<>();
    try {
      JSONArray ranges = new JSONArray(rangesJSON);
      for (int i = 0; i < ranges.length(); i++) {
        JSONObject range = ranges.getJSONObject(i);
        String type = range.getString("type");
        int start = range.getInt("start");
        int length = range.getInt("length");
        int depth = range.optInt("depth", 1);

        MarkdownRange markdownRange = new MarkdownRange(type, start, length, depth);
        if (markdownRange.getLength() == 0 || markdownRange.getEnd() > innerText.length()) {
          continue;
        }
        markdownRanges.add(markdownRange);
      }
    } catch (JSONException e) {
      return Collections.emptyList();
    }
    markdownRanges = splitRangesOnEmojis(markdownRanges, "italic");
    markdownRanges = splitRangesOnEmojis(markdownRanges, "strikethrough");
    return markdownRanges;
  }
  public synchronized List<MarkdownRange> parse(@NonNull String text, int parserId) {
    try {
      Systrace.beginSection(0, "parse");

      if (text.equals(mPrevText) && parserId == mPrevParserId) {
        return mPrevMarkdownRanges;
      }

      String json;
      try {
        Systrace.beginSection(0, "nativeParse");
        json = nativeParse(text, parserId);
      } catch (Exception e) {
        // Skip formatting, runGuarded will show the error in LogBox
        mPrevText = text;
        mPrevParserId = parserId;
        mPrevMarkdownRanges = Collections.emptyList();
        return mPrevMarkdownRanges;
      } finally {
        Systrace.endSection(0);
      }

      List<MarkdownRange> markdownRanges = parseRanges(json, text);
      Systrace.endSection(0);

      mPrevText = text;
      mPrevParserId = parserId;
      mPrevMarkdownRanges = markdownRanges;
      return mPrevMarkdownRanges;
    } finally {
      Systrace.endSection(0);
    }
  }
}