JsArgumentHelpers-inl.h 3.0 KB

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  1. /*
  2. * Copyright (c) Facebook, Inc. and its affiliates.
  3. *
  4. * This source code is licensed under the MIT license found in the
  5. * LICENSE file in the root directory of this source tree.
  6. */
  7. #pragma once
  8. #include <folly/dynamic.h>
  9. namespace facebook {
  10. namespace xplat {
  11. namespace detail {
  12. template <typename R, typename M, typename... T>
  13. R jsArg1(const folly::dynamic &arg, M asFoo, const T &... desc) {
  14. try {
  15. return (arg.*asFoo)();
  16. } catch (const folly::TypeError &ex) {
  17. throw JsArgumentException(folly::to<std::string>(
  18. "Error converting javascript arg ", desc..., " to C++: ", ex.what()));
  19. } catch (const std::range_error &ex) {
  20. throw JsArgumentException(folly::to<std::string>(
  21. "Could not convert argument ",
  22. desc...,
  23. " to required type: ",
  24. ex.what()));
  25. }
  26. }
  27. } // namespace detail
  28. template <typename R, typename... T>
  29. R jsArg(
  30. const folly::dynamic &arg,
  31. R (folly::dynamic::*asFoo)() const,
  32. const T &... desc) {
  33. return detail::jsArg1<R>(arg, asFoo, desc...);
  34. }
  35. template <typename R, typename... T>
  36. R jsArg(
  37. const folly::dynamic &arg,
  38. R (folly::dynamic::*asFoo)() const &,
  39. const T &... desc) {
  40. return detail::jsArg1<R>(arg, asFoo, desc...);
  41. }
  42. template <typename T>
  43. // NOLINTNEXTLINE (T62192316)
  44. typename detail::is_dynamic<T>::type &jsArgAsDynamic(T &&args, size_t n) {
  45. try {
  46. return args[n];
  47. } catch (const std::out_of_range &ex) {
  48. // Use 1-base counting for argument description.
  49. throw JsArgumentException(folly::to<std::string>(
  50. "JavaScript provided ",
  51. args.size(),
  52. " arguments for C++ method which references at least ",
  53. n + 1,
  54. " arguments: ",
  55. ex.what()));
  56. }
  57. }
  58. template <typename R>
  59. R jsArgN(
  60. const folly::dynamic &args,
  61. size_t n,
  62. R (folly::dynamic::*asFoo)() const) {
  63. return jsArg(jsArgAsDynamic(args, n), asFoo, n);
  64. }
  65. template <typename R>
  66. R jsArgN(
  67. const folly::dynamic &args,
  68. size_t n,
  69. R (folly::dynamic::*asFoo)() const &) {
  70. return jsArg(jsArgAsDynamic(args, n), asFoo, n);
  71. }
  72. namespace detail {
  73. // This is a helper for jsArgAsArray and jsArgAsObject.
  74. template <typename T>
  75. typename detail::is_dynamic<T>::type &jsArgAsType(
  76. T &&args,
  77. size_t n,
  78. const char *required,
  79. bool (folly::dynamic::*isFoo)() const) {
  80. T &ret = jsArgAsDynamic(args, n);
  81. if ((ret.*isFoo)()) {
  82. return ret;
  83. }
  84. // Use 1-base counting for argument description.
  85. throw JsArgumentException(folly::to<std::string>(
  86. "Argument ",
  87. n + 1,
  88. " of type ",
  89. ret.typeName(),
  90. " is not required type ",
  91. required));
  92. }
  93. } // end namespace detail
  94. template <typename T>
  95. typename detail::is_dynamic<T>::type &jsArgAsArray(T &&args, size_t n) {
  96. return detail::jsArgAsType(args, n, "Array", &folly::dynamic::isArray);
  97. }
  98. template <typename T>
  99. typename detail::is_dynamic<T>::type &jsArgAsObject(T &&args, size_t n) {
  100. return detail::jsArgAsType(args, n, "Object", &folly::dynamic::isObject);
  101. }
  102. } // namespace xplat
  103. } // namespace facebook