dom/html/MediaError.cpp

   1 /* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
   2 /* vim: set ts=8 sts=2 et sw=2 tw=80: */
   3 /* This Source Code Form is subject to the terms of the Mozilla Public
   4  * License, v. 2.0. If a copy of the MPL was not distributed with this
   5  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
   6
   7 #include "mozilla/dom/MediaError.h"
   8
   9 #include <string>
  10 #include <unordered_set>
  11
  12 #include "mozilla/dom/Document.h"
  13 #include "mozilla/dom/MediaErrorBinding.h"
  14 #include "nsContentUtils.h"
  15 #include "nsIScriptError.h"
  16 #include "jsapi.h"
  17 #include "js/Warnings.h"  // JS::WarnASCII
  18
  19 namespace mozilla::dom {
  20
  21 NS_IMPL_CYCLE_COLLECTION_WRAPPERCACHE(MediaError, mParent)
  22 NS_IMPL_CYCLE_COLLECTING_ADDREF(MediaError)
  23 NS_IMPL_CYCLE_COLLECTING_RELEASE(MediaError)
  24
  25 NS_INTERFACE_MAP_BEGIN_CYCLE_COLLECTION(MediaError)
  26   NS_WRAPPERCACHE_INTERFACE_MAP_ENTRY
  27   NS_INTERFACE_MAP_ENTRY(nsISupports)
  28 NS_INTERFACE_MAP_END
  29
  30 MediaError::MediaError(HTMLMediaElement* aParent, uint16_t aCode,
  31                        const nsACString& aMessage)
  32     : mParent(aParent), mCode(aCode), mMessage(aMessage) {}
  33
  34 void MediaError::GetMessage(nsAString& aResult) const {
  35   // When fingerprinting resistance is enabled, only messages in this list
  36   // can be returned to content script.
  37   // FIXME: An unordered_set seems overkill for this.
  38   static const std::unordered_set<std::string> whitelist = {
  39       "404: Not Found"
  40       // TODO
  41   };
  42
  43   const bool shouldBlank = whitelist.find(mMessage.get()) == whitelist.end();
  44
  45   if (shouldBlank) {
  46     // Print a warning message to JavaScript console to alert developers of
  47     // a non-whitelisted error message.
  48     nsAutoCString message =
  49         nsLiteralCString(
  50             "This error message will be blank when "
  51             "privacy.resistFingerprinting = true."
  52             "  If it is really necessary, please add it to the whitelist in"
  53             " MediaError::GetMessage: ") +
  54         mMessage;
  55     Document* ownerDoc = mParent->OwnerDoc();
  56     AutoJSAPI api;
  57     if (api.Init(ownerDoc->GetScopeObject())) {
  58       // We prefer this API because it can also print to our debug log and
  59       // try server's log viewer.
  60       JS::WarnASCII(api.cx(), "%s", message.get());
  61     } else {
  62       // If failed to use JS::WarnASCII, fall back to
  63       // nsContentUtils::ReportToConsoleNonLocalized, which can only print to
  64       // JavaScript console.
  65       nsContentUtils::ReportToConsoleNonLocalized(
  66           NS_ConvertASCIItoUTF16(message), nsIScriptError::warningFlag,
  67           "MediaError"_ns, ownerDoc);
  68     }
  69
  70     if (!nsContentUtils::IsCallerChrome() &&
  71         ownerDoc->ShouldResistFingerprinting(RFPTarget::MediaError)) {
  72       aResult.Truncate();
  73       return;
  74     }
  75   }
  76
  77   CopyUTF8toUTF16(mMessage, aResult);
  78 }
  79
  80 JSObject* MediaError::WrapObject(JSContext* aCx,
  81                                  JS::Handle<JSObject*> aGivenProto) {
  82   return MediaError_Binding::Wrap(aCx, this, aGivenProto);
  83 }
  84
  85 }  // namespace mozilla::dom