DXR is a code search and navigation tool aimed at making sense of large projects. It supports full-text and regex searches as well as structural queries.

Implementation

Mercurial (a5710687f9b4)

VCS Links

Line Code
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 198 199 200 201 202 203 204 205 206 207 208 209 210 211 212 213 214 215 216 217 218 219 220 221 222 223 224 225 226 227 228 229 230 231 232 233 234 235 236 237 238 239 240 241 242 243 244 245 246 247 248 249 250 251 252 253 254 255 256 257 258 259 260 261 262 263 264 265 266 267 268 269 270 271 272 273 274 275 276 277 278 279 280 281 282 283 284 285 286 287 288 289 290 291 292 293 294 295 296 297 298 299 300 301 302 303 304 305 306 307 308 309 310 311 312 313 314 315 316 317 318 319 320 321 322 323 324 325 326 327 328 329 330 331 332 333 334 335 336 337 338 339 340 341 342 343 344 345 346 347 348 349 350 351 352 353 354 355 356 357 358 359 360 361 362 363 364 365 366 367 368 369 370 371 372 373 374 375 376
/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
/* vim: set ts=8 sts=2 et sw=2 tw=80: */
/* This Source Code Form is subject to the terms of the Mozilla Public
 * License, v. 2.0. If a copy of the MPL was not distributed with this file,
 * You can obtain one at http://mozilla.org/MPL/2.0/. */

#ifndef mozilla_dom_ToJSValue_h
#define mozilla_dom_ToJSValue_h

#include "mozilla/TypeTraits.h"
#include "mozilla/Assertions.h"
#include "mozilla/UniquePtr.h"
#include "mozilla/dom/BindingUtils.h"
#include "mozilla/dom/NonRefcountedDOMObject.h"
#include "mozilla/dom/TypedArray.h"
#include "jsapi.h"
#include "nsISupports.h"
#include "nsTArray.h"
#include "nsWrapperCache.h"
#include "nsAutoPtr.h"

namespace mozilla {
namespace dom {

class Promise;
class WindowProxyHolder;

// If ToJSValue returns false, it must set an exception on the
// JSContext.

// Accept strings.
MOZ_MUST_USE bool ToJSValue(JSContext* aCx, const nsAString& aArgument,
                            JS::MutableHandle<JS::Value> aValue);

// Accept booleans.  But be careful here: if we just have a function that takes
// a boolean argument, then any pointer that doesn't match one of our other
// signatures/templates will get treated as a boolean, which is clearly not
// desirable.  So make this a template that only gets used if the argument type
// is actually boolean
template <typename T>
MOZ_MUST_USE typename EnableIf<IsSame<T, bool>::value, bool>::Type ToJSValue(
    JSContext* aCx, T aArgument, JS::MutableHandle<JS::Value> aValue) {
  // Make sure we're called in a compartment
  MOZ_ASSERT(JS::CurrentGlobalOrNull(aCx));

  aValue.setBoolean(aArgument);
  return true;
}

// Accept integer types
inline bool ToJSValue(JSContext* aCx, int32_t aArgument,
                      JS::MutableHandle<JS::Value> aValue) {
  // Make sure we're called in a compartment
  MOZ_ASSERT(JS::CurrentGlobalOrNull(aCx));

  aValue.setInt32(aArgument);
  return true;
}

inline bool ToJSValue(JSContext* aCx, uint32_t aArgument,
                      JS::MutableHandle<JS::Value> aValue) {
  // Make sure we're called in a compartment
  MOZ_ASSERT(JS::CurrentGlobalOrNull(aCx));

  aValue.setNumber(aArgument);
  return true;
}

inline bool ToJSValue(JSContext* aCx, int64_t aArgument,
                      JS::MutableHandle<JS::Value> aValue) {
  // Make sure we're called in a compartment
  MOZ_ASSERT(JS::CurrentGlobalOrNull(aCx));

  aValue.setNumber(double(aArgument));
  return true;
}

inline bool ToJSValue(JSContext* aCx, uint64_t aArgument,
                      JS::MutableHandle<JS::Value> aValue) {
  // Make sure we're called in a compartment
  MOZ_ASSERT(JS::CurrentGlobalOrNull(aCx));

  aValue.setNumber(double(aArgument));
  return true;
}

// accept floating point types
inline bool ToJSValue(JSContext* aCx, float aArgument,
                      JS::MutableHandle<JS::Value> aValue) {
  // Make sure we're called in a compartment
  MOZ_ASSERT(JS::CurrentGlobalOrNull(aCx));

  aValue.setNumber(aArgument);
  return true;
}

inline bool ToJSValue(JSContext* aCx, double aArgument,
                      JS::MutableHandle<JS::Value> aValue) {
  // Make sure we're called in a compartment
  MOZ_ASSERT(JS::CurrentGlobalOrNull(aCx));

  aValue.setNumber(aArgument);
  return true;
}

// Accept CallbackObjects
MOZ_MUST_USE inline bool ToJSValue(JSContext* aCx, CallbackObject& aArgument,
                                   JS::MutableHandle<JS::Value> aValue) {
  // Make sure we're called in a compartment
  MOZ_ASSERT(JS::CurrentGlobalOrNull(aCx));

  aValue.setObjectOrNull(aArgument.Callback(aCx));

  return MaybeWrapValue(aCx, aValue);
}

// Accept objects that inherit from nsWrapperCache (e.g. most
// DOM objects).
template <class T>
MOZ_MUST_USE typename EnableIf<IsBaseOf<nsWrapperCache, T>::value, bool>::Type
ToJSValue(JSContext* aCx, T& aArgument, JS::MutableHandle<JS::Value> aValue) {
  // Make sure we're called in a compartment
  MOZ_ASSERT(JS::CurrentGlobalOrNull(aCx));

  return GetOrCreateDOMReflector(aCx, aArgument, aValue);
}

// Accept non-refcounted DOM objects that do not inherit from
// nsWrapperCache.  Refcounted ones would be too much of a footgun:
// you could convert them to JS twice and get two different objects.
namespace binding_detail {
template <class T>
MOZ_MUST_USE
    typename EnableIf<IsBaseOf<NonRefcountedDOMObject, T>::value, bool>::Type
    ToJSValueFromPointerHelper(JSContext* aCx, T* aArgument,
                               JS::MutableHandle<JS::Value> aValue) {
  // Make sure we're called in a compartment
  MOZ_ASSERT(JS::CurrentGlobalOrNull(aCx));

  // This is a cut-down version of
  // WrapNewBindingNonWrapperCachedObject that doesn't need to deal
  // with nearly as many cases.
  if (!aArgument) {
    aValue.setNull();
    return true;
  }

  JS::Rooted<JSObject*> obj(aCx);
  if (!aArgument->WrapObject(aCx, nullptr, &obj)) {
    return false;
  }

  aValue.setObject(*obj);
  return true;
}
}  // namespace binding_detail

// We can take a non-refcounted non-wrapper-cached DOM object that lives in an
// nsAutoPtr.
template <class T>
MOZ_MUST_USE
    typename EnableIf<IsBaseOf<NonRefcountedDOMObject, T>::value, bool>::Type
    ToJSValue(JSContext* aCx, nsAutoPtr<T>&& aArgument,
              JS::MutableHandle<JS::Value> aValue) {
  if (!binding_detail::ToJSValueFromPointerHelper(aCx, aArgument.get(),
                                                  aValue)) {
    return false;
  }

  // JS object took ownership
  aArgument.forget();
  return true;
}

// We can take a non-refcounted non-wrapper-cached DOM object that lives in a
// UniquePtr.
template <class T>
MOZ_MUST_USE
    typename EnableIf<IsBaseOf<NonRefcountedDOMObject, T>::value, bool>::Type
    ToJSValue(JSContext* aCx, UniquePtr<T>&& aArgument,
              JS::MutableHandle<JS::Value> aValue) {
  if (!binding_detail::ToJSValueFromPointerHelper(aCx, aArgument.get(),
                                                  aValue)) {
    return false;
  }

  // JS object took ownership
  Unused << aArgument.release();
  return true;
}

// Accept typed arrays built from appropriate nsTArray values
template <typename T>
MOZ_MUST_USE
    typename EnableIf<IsBaseOf<AllTypedArraysBase, T>::value, bool>::Type
    ToJSValue(JSContext* aCx, const TypedArrayCreator<T>& aArgument,
              JS::MutableHandle<JS::Value> aValue) {
  // Make sure we're called in a compartment
  MOZ_ASSERT(JS::CurrentGlobalOrNull(aCx));

  JSObject* obj = aArgument.Create(aCx);
  if (!obj) {
    return false;
  }
  aValue.setObject(*obj);
  return true;
}

// Accept objects that inherit from nsISupports but not nsWrapperCache (e.g.
// DOM File).
template <class T>
MOZ_MUST_USE typename EnableIf<!IsBaseOf<nsWrapperCache, T>::value &&
                                   !IsBaseOf<CallbackObject, T>::value &&
                                   IsBaseOf<nsISupports, T>::value,
                               bool>::Type
ToJSValue(JSContext* aCx, T& aArgument, JS::MutableHandle<JS::Value> aValue) {
  // Make sure we're called in a compartment
  MOZ_ASSERT(JS::CurrentGlobalOrNull(aCx));

  xpcObjectHelper helper(ToSupports(&aArgument));
  JS::Rooted<JSObject*> scope(aCx, JS::CurrentGlobalOrNull(aCx));
  return XPCOMObjectToJsval(aCx, scope, helper, nullptr, true, aValue);
}

MOZ_MUST_USE bool ToJSValue(JSContext* aCx, const WindowProxyHolder& aArgument,
                            JS::MutableHandle<JS::Value> aValue);

// Accept nsRefPtr/nsCOMPtr
template <typename T>
MOZ_MUST_USE bool ToJSValue(JSContext* aCx, const nsCOMPtr<T>& aArgument,
                            JS::MutableHandle<JS::Value> aValue) {
  return ToJSValue(aCx, *aArgument.get(), aValue);
}

template <typename T>
MOZ_MUST_USE bool ToJSValue(JSContext* aCx, const RefPtr<T>& aArgument,
                            JS::MutableHandle<JS::Value> aValue) {
  return ToJSValue(aCx, *aArgument.get(), aValue);
}

template <typename T>
MOZ_MUST_USE bool ToJSValue(JSContext* aCx, const NonNull<T>& aArgument,
                            JS::MutableHandle<JS::Value> aValue) {
  return ToJSValue(aCx, *aArgument.get(), aValue);
}

// Accept WebIDL dictionaries
template <class T>
MOZ_MUST_USE typename EnableIf<IsBaseOf<DictionaryBase, T>::value, bool>::Type
ToJSValue(JSContext* aCx, const T& aArgument,
          JS::MutableHandle<JS::Value> aValue) {
  return aArgument.ToObjectInternal(aCx, aValue);
}

// Accept existing JS values (which may not be same-compartment with us
MOZ_MUST_USE inline bool ToJSValue(JSContext* aCx, const JS::Value& aArgument,
                                   JS::MutableHandle<JS::Value> aValue) {
  aValue.set(aArgument);
  return MaybeWrapValue(aCx, aValue);
}
MOZ_MUST_USE inline bool ToJSValue(JSContext* aCx,
                                   JS::Handle<JS::Value> aArgument,
                                   JS::MutableHandle<JS::Value> aValue) {
  aValue.set(aArgument);
  return MaybeWrapValue(aCx, aValue);
}

// Accept existing JS values on the Heap (which may not be same-compartment with
// us
MOZ_MUST_USE inline bool ToJSValue(JSContext* aCx,
                                   const JS::Heap<JS::Value>& aArgument,
                                   JS::MutableHandle<JS::Value> aValue) {
  aValue.set(aArgument);
  return MaybeWrapValue(aCx, aValue);
}

// Accept existing rooted JS values (which may not be same-compartment with us
MOZ_MUST_USE inline bool ToJSValue(JSContext* aCx,
                                   const JS::Rooted<JS::Value>& aArgument,
                                   JS::MutableHandle<JS::Value> aValue) {
  aValue.set(aArgument);
  return MaybeWrapValue(aCx, aValue);
}

// Accept existing rooted JS objects (which may not be same-compartment with
// us).
MOZ_MUST_USE inline bool ToJSValue(JSContext* aCx,
                                   const JS::Rooted<JSObject*>& aArgument,
                                   JS::MutableHandle<JS::Value> aValue) {
  aValue.setObjectOrNull(aArgument);
  return MaybeWrapObjectOrNullValue(aCx, aValue);
}

// Accept nsresult, for use in rejections, and create an XPCOM
// exception object representing that nsresult.
MOZ_MUST_USE bool ToJSValue(JSContext* aCx, nsresult aArgument,
                            JS::MutableHandle<JS::Value> aValue);

// Accept ErrorResult, for use in rejections, and create an exception
// representing the failure.  Note, the ErrorResult must indicate a failure
// with aArgument.Failure() returning true.
MOZ_MUST_USE bool ToJSValue(JSContext* aCx, ErrorResult& aArgument,
                            JS::MutableHandle<JS::Value> aValue);

// Accept owning WebIDL unions.
template <typename T>
MOZ_MUST_USE
    typename EnableIf<IsBaseOf<AllOwningUnionBase, T>::value, bool>::Type
    ToJSValue(JSContext* aCx, const T& aArgument,
              JS::MutableHandle<JS::Value> aValue) {
  JS::Rooted<JSObject*> global(aCx, JS::CurrentGlobalOrNull(aCx));
  return aArgument.ToJSVal(aCx, global, aValue);
}

// Accept pointers to other things we accept
template <typename T>
MOZ_MUST_USE typename EnableIf<IsPointer<T>::value, bool>::Type ToJSValue(
    JSContext* aCx, T aArgument, JS::MutableHandle<JS::Value> aValue) {
  return ToJSValue(aCx, *aArgument, aValue);
}

// Accept Promise objects, which need special handling.
MOZ_MUST_USE bool ToJSValue(JSContext* aCx, Promise& aArgument,
                            JS::MutableHandle<JS::Value> aValue);

// Accept arrays (and nested arrays) of other things we accept
template <typename T>
MOZ_MUST_USE bool ToJSValue(JSContext* aCx, T* aArguments, size_t aLength,
                            JS::MutableHandle<JS::Value> aValue);

template <typename T>
MOZ_MUST_USE bool ToJSValue(JSContext* aCx, const nsTArray<T>& aArgument,
                            JS::MutableHandle<JS::Value> aValue) {
  return ToJSValue(aCx, aArgument.Elements(), aArgument.Length(), aValue);
}

template <typename T>
MOZ_MUST_USE bool ToJSValue(JSContext* aCx, const FallibleTArray<T>& aArgument,
                            JS::MutableHandle<JS::Value> aValue) {
  return ToJSValue(aCx, aArgument.Elements(), aArgument.Length(), aValue);
}

template <typename T, int N>
MOZ_MUST_USE bool ToJSValue(JSContext* aCx, const T (&aArgument)[N],
                            JS::MutableHandle<JS::Value> aValue) {
  return ToJSValue(aCx, aArgument, N, aValue);
}

// Accept arrays of other things we accept
template <typename T>
MOZ_MUST_USE bool ToJSValue(JSContext* aCx, T* aArguments, size_t aLength,
                            JS::MutableHandle<JS::Value> aValue) {
  // Make sure we're called in a compartment
  MOZ_ASSERT(JS::CurrentGlobalOrNull(aCx));

  JS::RootedVector<JS::Value> v(aCx);
  if (!v.resize(aLength)) {
    return false;
  }
  for (size_t i = 0; i < aLength; ++i) {
    if (!ToJSValue(aCx, aArguments[i], v[i])) {
      return false;
    }
  }
  JSObject* arrayObj = JS_NewArrayObject(aCx, v);
  if (!arrayObj) {
    return false;
  }
  aValue.setObject(*arrayObj);
  return true;
}

}  // namespace dom
}  // namespace mozilla

#endif /* mozilla_dom_ToJSValue_h */