dom/quota/ScopedLogExtraInfo.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 file,
   5  * You can obtain one at http://mozilla.org/MPL/2.0/. */
   6
   7 #include "ScopedLogExtraInfo.h"
   8
   9 namespace mozilla::dom::quota {
  10
  11 #ifdef QM_SCOPED_LOG_EXTRA_INFO_ENABLED
  12 MOZ_THREAD_LOCAL(const nsACString*) ScopedLogExtraInfo::sQueryValue;
  13 MOZ_THREAD_LOCAL(const nsACString*) ScopedLogExtraInfo::sContextValue;
  14
  15 /* static */
  16 auto ScopedLogExtraInfo::FindSlot(const char* aTag) {
  17   // XXX For now, don't use a real map but just allow the known tag values.
  18
  19   if (aTag == kTagQuery) {
  20     return &sQueryValue;
  21   }
  22
  23   if (aTag == kTagContext) {
  24     return &sContextValue;
  25   }
  26
  27   MOZ_CRASH("Unknown tag!");
  28 }
  29
  30 ScopedLogExtraInfo::~ScopedLogExtraInfo() {
  31   if (mTag) {
  32     MOZ_ASSERT(&mCurrentValue == FindSlot(mTag)->get(),
  33                "Bad scoping of ScopedLogExtraInfo, must not be interleaved!");
  34
  35     FindSlot(mTag)->set(mPreviousValue);
  36   }
  37 }
  38
  39 ScopedLogExtraInfo::ScopedLogExtraInfo(ScopedLogExtraInfo&& aOther) noexcept
  40     : mTag(aOther.mTag),
  41       mPreviousValue(aOther.mPreviousValue),
  42       mCurrentValue(std::move(aOther.mCurrentValue)) {
  43   aOther.mTag = nullptr;
  44   FindSlot(mTag)->set(&mCurrentValue);
  45 }
  46
  47 /* static */ ScopedLogExtraInfo::ScopedLogExtraInfoMap
  48 ScopedLogExtraInfo::GetExtraInfoMap() {
  49   // This could be done in a cheaper way, but this is never called on a hot
  50   // path, so we anticipate using a real map inside here to make use simpler for
  51   // the caller(s).
  52
  53   ScopedLogExtraInfoMap map;
  54   if (sQueryValue.get()) {
  55     map.emplace(kTagQuery, sQueryValue.get());
  56   }
  57
  58   if (sContextValue.get()) {
  59     map.emplace(kTagContext, sContextValue.get());
  60   }
  61
  62   return map;
  63 }
  64
  65 /* static */ void ScopedLogExtraInfo::Initialize() {
  66   MOZ_ALWAYS_TRUE(sQueryValue.init());
  67   MOZ_ALWAYS_TRUE(sContextValue.init());
  68 }
  69
  70 void ScopedLogExtraInfo::AddInfo() {
  71   auto* slot = FindSlot(mTag);
  72   MOZ_ASSERT(slot);
  73   mPreviousValue = slot->get();
  74
  75   slot->set(&mCurrentValue);
  76 }
  77 #endif
  78
  79 }  // namespace mozilla::dom::quota