bool BytecodeUtil::getStrippedSource()

in plugins/experimental/wasm/lib/src/bytecode_util.cc [197:245]

• 42 lines of code
• 13 McCabe index (conditional complexity)

bool BytecodeUtil::getStrippedSource(std::string_view bytecode, std::string &ret) {
  // Check Wasm header.
  if (!checkWasmHeader(bytecode)) {
    return false;
  }

  // Skip the Wasm header.
  const char *pos = bytecode.data() + 8;
  const char *end = bytecode.data() + bytecode.size();
  while (pos < end) {
    const auto *const section_start = pos;
    if (pos + 1 > end) {
      return false;
    }
    const auto section_type = *pos++;
    uint32_t section_len = 0;
    if (!parseVarint(pos, end, section_len) || pos + section_len > end) {
      return false;
    }
    if (section_type == 0 /* custom section */) {
      const auto *const section_data_start = pos;
      uint32_t section_name_len = 0;
      if (!parseVarint(pos, end, section_name_len) || pos + section_name_len > end) {
        return false;
      }
      auto section_name = std::string_view(pos, section_name_len);
      if (section_name.find("precompiled_") != std::string::npos) {
        // If this is the first "precompiled_" section, then save everything
        // before it, otherwise skip it.
        if (ret.empty()) {
          const char *start = bytecode.data();
          ret.append(start, section_start);
        }
      }
      pos = section_data_start + section_len;
    } else {
      pos += section_len;
      // Save this section if we already saw a custom "precompiled_" section.
      if (!ret.empty()) {
        ret.append(section_start, pos);
      }
    }
  }
  if (ret.empty()) {
    // Copy the original source code if it is empty.
    ret = std::string(bytecode);
  }
  return true;
}