Method parseCssFiles

lib/Epub/Epub.cpp:285–362

}

void Epub::parseCssFiles() const {
  // Maximum CSS file size we'll attempt to parse (uncompressed)
  // Larger files risk memory exhaustion on ESP32
  constexpr size_t MAX_CSS_FILE_SIZE = 128 * 1024;  // 128KB
  // Minimum heap required before attempting CSS parsing
  constexpr size_t MIN_HEAP_FOR_CSS_PARSING = 64 * 1024;  // 64KB

  if (cssFiles.empty()) {
    LOG_DBG("EBP", "No CSS files to parse, but CssParser created for inline styles");
  }

  LOG_DBG("EBP", "CSS files to parse: %zu", cssFiles.size());

  // See if we have a cached version of the CSS rules
  if (cssParser->hasCache()) {
    LOG_DBG("EBP", "CSS cache exists, skipping parseCssFiles");
    return;
  }

  // No cache yet - parse CSS files
  for (const auto& cssPath : cssFiles) {
    LOG_DBG("EBP", "Parsing CSS file: %s", cssPath.c_str());

    // Check heap before parsing - CSS parsing allocates heavily
    const uint32_t freeHeap = ESP.getFreeHeap();
    if (freeHeap < MIN_HEAP_FOR_CSS_PARSING) {
      LOG_ERR("EBP", "Insufficient heap for CSS parsing (%u bytes free, need %zu), skipping: %s", freeHeap,
              MIN_HEAP_FOR_CSS_PARSING, cssPath.c_str());
      continue;
    }

    // Check CSS file size before decompressing - skip files that are too large
    size_t cssFileSize = 0;
    if (getItemSize(cssPath, &cssFileSize)) {
      if (cssFileSize > MAX_CSS_FILE_SIZE) {
        LOG_ERR("EBP", "CSS file too large (%zu bytes > %zu max), skipping: %s", cssFileSize, MAX_CSS_FILE_SIZE,
                cssPath.c_str());
        continue;
      }
    }

    // Extract CSS file to temp location
    const auto tmpCssPath = getCachePath() + "/.tmp.css";
    HalFile tempCssFile;
    if (!Storage.openFileForWrite("EBP", tmpCssPath, tempCssFile)) {
      LOG_ERR("EBP", "Could not create temp CSS file");
      continue;
    }
    if (!readItemContentsToStream(cssPath, tempCssFile, 1024)) {
      LOG_ERR("EBP", "Could not read CSS file: %s", cssPath.c_str());
      // Explicitly close() file before calling Storage.remove()
      tempCssFile.close();
      Storage.remove(tmpCssPath.c_str());
      continue;
    }
    // Explicitly close() file before reopening for reading
    tempCssFile.close();