chrome/nsChromeRegistryChrome.cpp
author Jim Blandy <jimb@mozilla.com>
Tue, 12 Feb 2019 08:16:16 +0000
changeset 458932 414b2c238839c321dee78a9d927c968f1e52ae79
parent 454520 5f4630838d46dd81dadb13220a4af0da9e23a619
child 461884 02e1b59e669da81a15505dacd708e6fc7f567d5b
permissions -rw-r--r--
Bug 1145201: Replace EnqueuePromiseJobCallback and GetIncumbentGlobalCallback with new JobQueue abstract base class. r=arai,smaug While the behavior of ECMAScript Promises and their associated job queue is covered by the ECMAScript standard, the HTML specification amends that with additional behavior the web platform requires. To support this, SpiderMonkey provides hooks the embedding can set to replace SpiderMonkey's queue with its own implementation. At present, these hooks are C-style function-pointer-and-void-pointer pairs, which are awkward to handle and mistake-prone, as passing a function the wrong void* is not a type error. Later patches in this series must add new hooks, making a bad situation worse. A C++ abstract base class is a well-typed alternative. This introduces a new `JS::JobQueue` abstract class, and adapts SpiderMonkey's internal job queue and Gecko's customization to use it. `GetIncumbentGlobalCallback` and `EnqueuePromiseJobCallback` become virtual methods. Within SpiderMonkey, the patch gathers the various fields of JSContext that implement the internal queue into their own type, js::InternalJobQueue. Various jsfriendapi functions become veneers for calls to methods specific to the derived class. The InternalJobQueue type itself remains private to SpiderMonkey, as it uses types like TraceableFifo, derived from Fifo, that are not part of SpiderMonkey's public API. Within Gecko, CycleCollectedJSContext acquires JS::JobQueue as a private base class, and a few static methods are cleaned up nicely. There are a few other hooks defined in js/public/Promise.h that might make sense to turn into virtual methods on JobQueue. For example, DispatchToEventLoopCallback, used for resolving promises of results from off-main-thread tasks, is probably necessarily connected to the JobQueue implementation in use, so it might not be sensible to set one without the other. But it was left unchanged to reduce this patch's size. Differential Revision: https://phabricator.services.mozilla.com/D17544

/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
/* vim: set ts=2 sts=2 sw=2 et 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/. */

#include "mozilla/dom/ContentParent.h"
#include "RegistryMessageUtils.h"
#include "nsResProtocolHandler.h"

#include "nsChromeRegistryChrome.h"

#if defined(XP_WIN)
#  include <windows.h>
#elif defined(XP_MACOSX)
#  include <CoreServices/CoreServices.h>
#endif

#include "nsArrayEnumerator.h"
#include "nsComponentManager.h"
#include "nsEnumeratorUtils.h"
#include "nsNetUtil.h"
#include "nsStringEnumerator.h"
#include "nsTextFormatter.h"
#include "nsXPCOMCIDInternal.h"

#include "mozilla/LookAndFeel.h"
#include "mozilla/Unused.h"
#include "mozilla/intl/LocaleService.h"

#include "nsIObserverService.h"
#include "nsIPrefBranch.h"
#include "nsIPrefService.h"
#include "mozilla/Preferences.h"
#include "nsIResProtocolHandler.h"
#include "nsIScriptError.h"
#include "nsIXULRuntime.h"

#define SELECTED_SKIN_PREF "general.skins.selectedSkin"
#define PACKAGE_OVERRIDE_BRANCH "chrome.override_package."

using namespace mozilla;
using mozilla::dom::ContentParent;
using mozilla::dom::PContentParent;
using mozilla::intl::LocaleService;

// We use a "best-fit" algorithm for matching locales and themes.
// 1) the exact selected locale/theme
// 2) (locales only) same language, different country
//    e.g. en-GB is the selected locale, only en-US is available
// 3) any available locale/theme

/**
 * Match the language-part of two lang-COUNTRY codes, hopefully but
 * not guaranteed to be in the form ab-CD or abz-CD. "ab" should also
 * work, any other garbage-in will produce undefined results as long
 * as it does not crash.
 */
static bool LanguagesMatch(const nsACString& a, const nsACString& b) {
  if (a.Length() < 2 || b.Length() < 2) return false;

  nsACString::const_iterator as, ae, bs, be;
  a.BeginReading(as);
  a.EndReading(ae);
  b.BeginReading(bs);
  b.EndReading(be);

  while (*as == *bs) {
    if (*as == '-') return true;

    ++as;
    ++bs;

    // reached the end
    if (as == ae && bs == be) return true;

    // "a" is short
    if (as == ae) return (*bs == '-');

    // "b" is short
    if (bs == be) return (*as == '-');
  }

  return false;
}

nsChromeRegistryChrome::nsChromeRegistryChrome()
    : mProfileLoaded(false), mDynamicRegistration(true) {}

nsChromeRegistryChrome::~nsChromeRegistryChrome() {}

nsresult nsChromeRegistryChrome::Init() {
  nsresult rv = nsChromeRegistry::Init();
  if (NS_FAILED(rv)) return rv;

  mSelectedSkin = NS_LITERAL_CSTRING("classic/1.0");

  bool safeMode = false;
  nsCOMPtr<nsIXULRuntime> xulrun(do_GetService(XULAPPINFO_SERVICE_CONTRACTID));
  if (xulrun) xulrun->GetInSafeMode(&safeMode);

  nsCOMPtr<nsIPrefService> prefserv(do_GetService(NS_PREFSERVICE_CONTRACTID));
  nsCOMPtr<nsIPrefBranch> prefs;

  if (prefserv) {
    if (safeMode) {
      prefserv->GetDefaultBranch(nullptr, getter_AddRefs(prefs));
    } else {
      prefs = do_QueryInterface(prefserv);
    }
  }

  if (!prefs) {
    NS_WARNING("Could not get pref service!");
  } else {
    nsAutoCString provider;
    rv = prefs->GetCharPref(SELECTED_SKIN_PREF, provider);
    if (NS_SUCCEEDED(rv)) mSelectedSkin = provider;

    rv = prefs->AddObserver(SELECTED_SKIN_PREF, this, true);
  }

  nsCOMPtr<nsIObserverService> obsService =
      mozilla::services::GetObserverService();
  if (obsService) {
    obsService->AddObserver(this, "profile-initial-state", true);
    obsService->AddObserver(this, "intl:app-locales-changed", true);
  }

  return NS_OK;
}

NS_IMETHODIMP
nsChromeRegistryChrome::CheckForOSAccessibility() {
  int32_t useAccessibilityTheme =
      LookAndFeel::GetInt(LookAndFeel::eIntID_UseAccessibilityTheme, 0);

  if (useAccessibilityTheme) {
    /* Set the skin to classic and remove pref observers */
    if (!mSelectedSkin.EqualsLiteral("classic/1.0")) {
      mSelectedSkin.AssignLiteral("classic/1.0");
      RefreshSkins();
    }

    nsCOMPtr<nsIPrefBranch> prefs(do_GetService(NS_PREFSERVICE_CONTRACTID));
    if (prefs) {
      prefs->RemoveObserver(SELECTED_SKIN_PREF, this);
    }
  }

  return NS_OK;
}

NS_IMETHODIMP
nsChromeRegistryChrome::GetLocalesForPackage(
    const nsACString& aPackage, nsIUTF8StringEnumerator** aResult) {
  nsCString realpackage;
  nsresult rv = OverrideLocalePackage(aPackage, realpackage);
  if (NS_FAILED(rv)) return rv;

  nsTArray<nsCString>* a = new nsTArray<nsCString>;
  if (!a) return NS_ERROR_OUT_OF_MEMORY;

  PackageEntry* entry;
  if (mPackagesHash.Get(realpackage, &entry)) {
    entry->locales.EnumerateToArray(a);
  }

  rv = NS_NewAdoptingUTF8StringEnumerator(aResult, a);
  if (NS_FAILED(rv)) delete a;

  return rv;
}

NS_IMETHODIMP
nsChromeRegistryChrome::IsLocaleRTL(const nsACString& package, bool* aResult) {
  *aResult = false;

  nsAutoCString locale;
  GetSelectedLocale(package, false, locale);
  if (locale.Length() < 2) return NS_OK;

  *aResult = GetDirectionForLocale(locale);
  return NS_OK;
}

/**
 * This method negotiates only between the app locale and the available
 * chrome packages.
 *
 * If you want to get the current application's UI locale, please use
 * LocaleService::GetAppLocaleAsLangTag.
 */
nsresult nsChromeRegistryChrome::GetSelectedLocale(const nsACString& aPackage,
                                                   bool aAsBCP47,
                                                   nsACString& aLocale) {
  nsAutoCString reqLocale;
  if (aPackage.EqualsLiteral("global")) {
    LocaleService::GetInstance()->GetAppLocaleAsLangTag(reqLocale);
  } else {
    AutoTArray<nsCString, 10> requestedLocales;
    LocaleService::GetInstance()->GetRequestedLocales(requestedLocales);
    reqLocale.Assign(requestedLocales[0]);
  }

  nsCString realpackage;
  nsresult rv = OverrideLocalePackage(aPackage, realpackage);
  if (NS_FAILED(rv)) return rv;
  PackageEntry* entry;
  if (!mPackagesHash.Get(realpackage, &entry)) return NS_ERROR_FILE_NOT_FOUND;

  aLocale = entry->locales.GetSelected(reqLocale, nsProviderArray::LOCALE);
  if (aLocale.IsEmpty()) return NS_ERROR_FAILURE;

  if (aAsBCP47) {
    SanitizeForBCP47(aLocale);
  }

  return NS_OK;
}

nsresult nsChromeRegistryChrome::OverrideLocalePackage(
    const nsACString& aPackage, nsACString& aOverride) {
  const nsACString& pref =
      NS_LITERAL_CSTRING(PACKAGE_OVERRIDE_BRANCH) + aPackage;
  nsAutoCString override;
  nsresult rv = mozilla::Preferences::GetCString(PromiseFlatCString(pref).get(),
                                                 override);
  if (NS_SUCCEEDED(rv)) {
    aOverride = override;
  } else {
    aOverride = aPackage;
  }
  return NS_OK;
}

NS_IMETHODIMP
nsChromeRegistryChrome::Observe(nsISupports* aSubject, const char* aTopic,
                                const char16_t* someData) {
  nsresult rv = NS_OK;

  if (!strcmp(NS_PREFBRANCH_PREFCHANGE_TOPIC_ID, aTopic)) {
    nsCOMPtr<nsIPrefBranch> prefs(do_QueryInterface(aSubject));
    NS_ASSERTION(prefs, "Bad observer call!");

    NS_ConvertUTF16toUTF8 pref(someData);

    if (pref.EqualsLiteral(SELECTED_SKIN_PREF)) {
      nsAutoCString provider;
      rv = prefs->GetCharPref(pref.get(), provider);
      if (NS_FAILED(rv)) {
        NS_ERROR("Couldn't get new skin pref!");
        return rv;
      }

      mSelectedSkin = provider;
      RefreshSkins();
    } else {
      NS_ERROR("Unexpected pref!");
    }
  } else if (!strcmp("profile-initial-state", aTopic)) {
    mProfileLoaded = true;
  } else if (!strcmp("intl:app-locales-changed", aTopic)) {
    if (mProfileLoaded) {
      FlushAllCaches();
    }
  } else {
    NS_ERROR("Unexpected observer topic!");
  }

  return rv;
}

NS_IMETHODIMP
nsChromeRegistryChrome::CheckForNewChrome() {
  mPackagesHash.Clear();
  mOverrideTable.Clear();

  mDynamicRegistration = false;

  nsComponentManagerImpl::gComponentManager->RereadChromeManifests();

  mDynamicRegistration = true;

  SendRegisteredChrome(nullptr);
  return NS_OK;
}

static void SerializeURI(nsIURI* aURI, SerializedURI& aSerializedURI) {
  if (!aURI) return;

  aURI->GetSpec(aSerializedURI.spec);
}

void nsChromeRegistryChrome::SendRegisteredChrome(
    mozilla::dom::PContentParent* aParent) {
  InfallibleTArray<ChromePackage> packages;
  InfallibleTArray<SubstitutionMapping> resources;
  InfallibleTArray<OverrideMapping> overrides;

  for (auto iter = mPackagesHash.Iter(); !iter.Done(); iter.Next()) {
    ChromePackage chromePackage;
    ChromePackageFromPackageEntry(iter.Key(), iter.UserData(), &chromePackage,
                                  mSelectedSkin);
    packages.AppendElement(chromePackage);
  }

  // If we were passed a parent then a new child process has been created and
  // has requested all of the chrome so send it the resources too. Otherwise
  // resource mappings are sent by the resource protocol handler dynamically.
  if (aParent) {
    nsCOMPtr<nsIIOService> io(do_GetIOService());
    NS_ENSURE_TRUE_VOID(io);

    nsCOMPtr<nsIProtocolHandler> ph;
    nsresult rv = io->GetProtocolHandler("resource", getter_AddRefs(ph));
    NS_ENSURE_SUCCESS_VOID(rv);

    nsCOMPtr<nsIResProtocolHandler> irph(do_QueryInterface(ph));
    nsResProtocolHandler* rph = static_cast<nsResProtocolHandler*>(irph.get());
    rv = rph->CollectSubstitutions(resources);
    NS_ENSURE_SUCCESS_VOID(rv);
  }

  for (auto iter = mOverrideTable.Iter(); !iter.Done(); iter.Next()) {
    SerializedURI chromeURI, overrideURI;

    SerializeURI(iter.Key(), chromeURI);
    SerializeURI(iter.UserData(), overrideURI);

    OverrideMapping override = {chromeURI, overrideURI};
    overrides.AppendElement(override);
  }

  nsAutoCString appLocale;
  LocaleService::GetInstance()->GetAppLocaleAsLangTag(appLocale);

  if (aParent) {
    bool success = aParent->SendRegisterChrome(packages, resources, overrides,
                                               appLocale, false);
    NS_ENSURE_TRUE_VOID(success);
  } else {
    nsTArray<ContentParent*> parents;
    ContentParent::GetAll(parents);
    if (!parents.Length()) return;

    for (uint32_t i = 0; i < parents.Length(); i++) {
      DebugOnly<bool> success = parents[i]->SendRegisterChrome(
          packages, resources, overrides, appLocale, true);
      NS_WARNING_ASSERTION(success,
                           "couldn't reset a child's registered chrome");
    }
  }
}

/* static */ void nsChromeRegistryChrome::ChromePackageFromPackageEntry(
    const nsACString& aPackageName, PackageEntry* aPackage,
    ChromePackage* aChromePackage, const nsCString& aSelectedSkin) {
  nsAutoCString appLocale;
  LocaleService::GetInstance()->GetAppLocaleAsLangTag(appLocale);

  SerializeURI(aPackage->baseURI, aChromePackage->contentBaseURI);
  SerializeURI(aPackage->locales.GetBase(appLocale, nsProviderArray::LOCALE),
               aChromePackage->localeBaseURI);
  SerializeURI(aPackage->skins.GetBase(aSelectedSkin, nsProviderArray::ANY),
               aChromePackage->skinBaseURI);
  aChromePackage->package = aPackageName;
  aChromePackage->flags = aPackage->flags;
}

static bool CanLoadResource(nsIURI* aResourceURI) {
  bool isLocalResource = false;
  (void)NS_URIChainHasFlags(aResourceURI,
                            nsIProtocolHandler::URI_IS_LOCAL_RESOURCE,
                            &isLocalResource);
  return isLocalResource;
}

nsIURI* nsChromeRegistryChrome::GetBaseURIFromPackage(
    const nsCString& aPackage, const nsCString& aProvider,
    const nsCString& aPath) {
  PackageEntry* entry;
  if (!mPackagesHash.Get(aPackage, &entry)) {
    if (!mInitialized) return nullptr;

    LogMessage("No chrome package registered for chrome://%s/%s/%s",
               aPackage.get(), aProvider.get(), aPath.get());

    return nullptr;
  }

  if (aProvider.EqualsLiteral("locale")) {
    nsAutoCString appLocale;
    LocaleService::GetInstance()->GetAppLocaleAsLangTag(appLocale);
    return entry->locales.GetBase(appLocale, nsProviderArray::LOCALE);
  } else if (aProvider.EqualsLiteral("skin")) {
    return entry->skins.GetBase(mSelectedSkin, nsProviderArray::ANY);
  } else if (aProvider.EqualsLiteral("content")) {
    return entry->baseURI;
  }
  return nullptr;
}

nsresult nsChromeRegistryChrome::GetFlagsFromPackage(const nsCString& aPackage,
                                                     uint32_t* aFlags) {
  PackageEntry* entry;
  if (!mPackagesHash.Get(aPackage, &entry)) return NS_ERROR_FILE_NOT_FOUND;

  *aFlags = entry->flags;
  return NS_OK;
}

nsChromeRegistryChrome::ProviderEntry*
nsChromeRegistryChrome::nsProviderArray::GetProvider(
    const nsACString& aPreferred, MatchType aType) {
  size_t i = mArray.Length();
  if (!i) return nullptr;

  ProviderEntry* found = nullptr;  // Only set if we find a partial-match locale
  ProviderEntry* entry = nullptr;

  while (i--) {
    entry = &mArray[i];
    if (aPreferred.Equals(entry->provider)) return entry;

    if (aType != LOCALE) continue;

    if (LanguagesMatch(aPreferred, entry->provider)) {
      found = entry;
      continue;
    }

    if (!found && entry->provider.EqualsLiteral("en-US")) found = entry;
  }

  if (!found && aType != EXACT) return entry;

  return found;
}

nsIURI* nsChromeRegistryChrome::nsProviderArray::GetBase(
    const nsACString& aPreferred, MatchType aType) {
  ProviderEntry* provider = GetProvider(aPreferred, aType);

  if (!provider) return nullptr;

  return provider->baseURI;
}

const nsACString& nsChromeRegistryChrome::nsProviderArray::GetSelected(
    const nsACString& aPreferred, MatchType aType) {
  ProviderEntry* entry = GetProvider(aPreferred, aType);

  if (entry) return entry->provider;

  return EmptyCString();
}

void nsChromeRegistryChrome::nsProviderArray::SetBase(
    const nsACString& aProvider, nsIURI* aBaseURL) {
  ProviderEntry* provider = GetProvider(aProvider, EXACT);

  if (provider) {
    provider->baseURI = aBaseURL;
    return;
  }

  // no existing entries, add a new one
  mArray.AppendElement(ProviderEntry(aProvider, aBaseURL));
}

void nsChromeRegistryChrome::nsProviderArray::EnumerateToArray(
    nsTArray<nsCString>* a) {
  int32_t i = mArray.Length();
  while (i--) {
    a->AppendElement(mArray[i].provider);
  }
}

nsIURI* nsChromeRegistry::ManifestProcessingContext::GetManifestURI() {
  if (!mManifestURI) {
    nsCString uri;
    mFile.GetURIString(uri);
    NS_NewURI(getter_AddRefs(mManifestURI), uri);
  }
  return mManifestURI;
}

already_AddRefed<nsIURI>
nsChromeRegistry::ManifestProcessingContext::ResolveURI(const char* uri) {
  nsIURI* baseuri = GetManifestURI();
  if (!baseuri) return nullptr;

  nsCOMPtr<nsIURI> resolved;
  nsresult rv = NS_NewURI(getter_AddRefs(resolved), uri, baseuri);
  if (NS_FAILED(rv)) return nullptr;

  return resolved.forget();
}

static void EnsureLowerCase(char* aBuf) {
  for (; *aBuf; ++aBuf) {
    char ch = *aBuf;
    if (ch >= 'A' && ch <= 'Z') *aBuf = ch + 'a' - 'A';
  }
}

static void SendManifestEntry(const ChromeRegistryItem& aItem) {
  nsTArray<ContentParent*> parents;
  ContentParent::GetAll(parents);
  if (!parents.Length()) return;

  for (uint32_t i = 0; i < parents.Length(); i++) {
    Unused << parents[i]->SendRegisterChromeItem(aItem);
  }
}

void nsChromeRegistryChrome::ManifestContent(ManifestProcessingContext& cx,
                                             int lineno, char* const* argv,
                                             int flags) {
  char* package = argv[0];
  char* uri = argv[1];

  EnsureLowerCase(package);

  nsCOMPtr<nsIURI> resolved = cx.ResolveURI(uri);
  if (!resolved) {
    LogMessageWithContext(
        cx.GetManifestURI(), lineno, nsIScriptError::warningFlag,
        "During chrome registration, unable to create URI '%s'.", uri);
    return;
  }

  if (!CanLoadResource(resolved)) {
    LogMessageWithContext(resolved, lineno, nsIScriptError::warningFlag,
                          "During chrome registration, cannot register "
                          "non-local URI '%s' as content.",
                          uri);
    return;
  }

  nsDependentCString packageName(package);
  PackageEntry* entry = mPackagesHash.LookupOrAdd(packageName);
  entry->baseURI = resolved;
  entry->flags = flags;

  if (mDynamicRegistration) {
    ChromePackage chromePackage;
    ChromePackageFromPackageEntry(packageName, entry, &chromePackage,
                                  mSelectedSkin);
    SendManifestEntry(chromePackage);
  }
}

void nsChromeRegistryChrome::ManifestLocale(ManifestProcessingContext& cx,
                                            int lineno, char* const* argv,
                                            int flags) {
  char* package = argv[0];
  char* provider = argv[1];
  char* uri = argv[2];

  EnsureLowerCase(package);

  nsCOMPtr<nsIURI> resolved = cx.ResolveURI(uri);
  if (!resolved) {
    LogMessageWithContext(
        cx.GetManifestURI(), lineno, nsIScriptError::warningFlag,
        "During chrome registration, unable to create URI '%s'.", uri);
    return;
  }

  if (!CanLoadResource(resolved)) {
    LogMessageWithContext(resolved, lineno, nsIScriptError::warningFlag,
                          "During chrome registration, cannot register "
                          "non-local URI '%s' as content.",
                          uri);
    return;
  }

  nsDependentCString packageName(package);
  PackageEntry* entry = mPackagesHash.LookupOrAdd(packageName);
  entry->locales.SetBase(nsDependentCString(provider), resolved);

  if (mDynamicRegistration) {
    ChromePackage chromePackage;
    ChromePackageFromPackageEntry(packageName, entry, &chromePackage,
                                  mSelectedSkin);
    SendManifestEntry(chromePackage);
  }

  // We use mainPackage as the package we track for reporting new locales being
  // registered. For most cases it will be "global", but for Fennec it will be
  // "browser".
  nsAutoCString mainPackage;
  nsresult rv =
      OverrideLocalePackage(NS_LITERAL_CSTRING("global"), mainPackage);
  if (NS_FAILED(rv)) {
    return;
  }
}

void nsChromeRegistryChrome::ManifestSkin(ManifestProcessingContext& cx,
                                          int lineno, char* const* argv,
                                          int flags) {
  char* package = argv[0];
  char* provider = argv[1];
  char* uri = argv[2];

  EnsureLowerCase(package);

  nsCOMPtr<nsIURI> resolved = cx.ResolveURI(uri);
  if (!resolved) {
    LogMessageWithContext(
        cx.GetManifestURI(), lineno, nsIScriptError::warningFlag,
        "During chrome registration, unable to create URI '%s'.", uri);
    return;
  }

  if (!CanLoadResource(resolved)) {
    LogMessageWithContext(resolved, lineno, nsIScriptError::warningFlag,
                          "During chrome registration, cannot register "
                          "non-local URI '%s' as content.",
                          uri);
    return;
  }

  nsDependentCString packageName(package);
  PackageEntry* entry = mPackagesHash.LookupOrAdd(packageName);
  entry->skins.SetBase(nsDependentCString(provider), resolved);

  if (mDynamicRegistration) {
    ChromePackage chromePackage;
    ChromePackageFromPackageEntry(packageName, entry, &chromePackage,
                                  mSelectedSkin);
    SendManifestEntry(chromePackage);
  }
}

void nsChromeRegistryChrome::ManifestOverride(ManifestProcessingContext& cx,
                                              int lineno, char* const* argv,
                                              int flags) {
  char* chrome = argv[0];
  char* resolved = argv[1];

  nsCOMPtr<nsIURI> chromeuri = cx.ResolveURI(chrome);
  nsCOMPtr<nsIURI> resolveduri = cx.ResolveURI(resolved);
  if (!chromeuri || !resolveduri) {
    LogMessageWithContext(cx.GetManifestURI(), lineno,
                          nsIScriptError::warningFlag,
                          "During chrome registration, unable to create URI.");
    return;
  }

  if (cx.mType == NS_SKIN_LOCATION) {
    bool chromeSkinOnly = false;
    nsresult rv = chromeuri->SchemeIs("chrome", &chromeSkinOnly);
    chromeSkinOnly = chromeSkinOnly && NS_SUCCEEDED(rv);
    if (chromeSkinOnly) {
      rv = resolveduri->SchemeIs("chrome", &chromeSkinOnly);
      chromeSkinOnly = chromeSkinOnly && NS_SUCCEEDED(rv);
    }
    if (chromeSkinOnly) {
      nsAutoCString chromePath, resolvedPath;
      chromeuri->GetPathQueryRef(chromePath);
      resolveduri->GetPathQueryRef(resolvedPath);
      chromeSkinOnly =
          StringBeginsWith(chromePath, NS_LITERAL_CSTRING("/skin/")) &&
          StringBeginsWith(resolvedPath, NS_LITERAL_CSTRING("/skin/"));
    }
    if (!chromeSkinOnly) {
      LogMessageWithContext(
          cx.GetManifestURI(), lineno, nsIScriptError::warningFlag,
          "Cannot register non-chrome://.../skin/ URIs '%s' and '%s' as "
          "overrides and/or to be overridden from a skin manifest.",
          chrome, resolved);
      return;
    }
  }

  if (!CanLoadResource(resolveduri)) {
    LogMessageWithContext(
        cx.GetManifestURI(), lineno, nsIScriptError::warningFlag,
        "Cannot register non-local URI '%s' for an override.", resolved);
    return;
  }
  mOverrideTable.Put(chromeuri, resolveduri);

  if (mDynamicRegistration) {
    SerializedURI serializedChrome;
    SerializedURI serializedOverride;

    SerializeURI(chromeuri, serializedChrome);
    SerializeURI(resolveduri, serializedOverride);

    OverrideMapping override = {serializedChrome, serializedOverride};
    SendManifestEntry(override);
  }
}

void nsChromeRegistryChrome::ManifestResource(ManifestProcessingContext& cx,
                                              int lineno, char* const* argv,
                                              int flags) {
  char* package = argv[0];
  char* uri = argv[1];

  EnsureLowerCase(package);
  nsDependentCString host(package);

  nsCOMPtr<nsIIOService> io = mozilla::services::GetIOService();
  if (!io) {
    NS_WARNING("No IO service trying to process chrome manifests");
    return;
  }

  nsCOMPtr<nsIProtocolHandler> ph;
  nsresult rv = io->GetProtocolHandler("resource", getter_AddRefs(ph));
  if (NS_FAILED(rv)) return;

  nsCOMPtr<nsIResProtocolHandler> rph = do_QueryInterface(ph);

  nsCOMPtr<nsIURI> resolved = cx.ResolveURI(uri);
  if (!resolved) {
    LogMessageWithContext(
        cx.GetManifestURI(), lineno, nsIScriptError::warningFlag,
        "During chrome registration, unable to create URI '%s'.", uri);
    return;
  }

  if (!CanLoadResource(resolved)) {
    LogMessageWithContext(
        cx.GetManifestURI(), lineno, nsIScriptError::warningFlag,
        "Warning: cannot register non-local URI '%s' as a resource.", uri);
    return;
  }

  // By default, Firefox resources are not content-accessible unless the
  // manifests opts in.
  bool contentAccessible = (flags & nsChromeRegistry::CONTENT_ACCESSIBLE);

  uint32_t substitutionFlags = 0;
  if (contentAccessible) {
    substitutionFlags |= nsIResProtocolHandler::ALLOW_CONTENT_ACCESS;
  }
  rv = rph->SetSubstitutionWithFlags(host, resolved, substitutionFlags);
  if (NS_FAILED(rv)) {
    LogMessageWithContext(cx.GetManifestURI(), lineno,
                          nsIScriptError::warningFlag,
                          "Warning: cannot set substitution for '%s'.", uri);
  }
}