layout/base/nsAutoLayoutPhase.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 #ifndef DEBUG
   8 static_assert(false, "This should not be compiled in !DEBUG");
   9 #endif  // DEBUG
  10
  11 #include "nsAutoLayoutPhase.h"
  12 #include "nsPresContext.h"
  13 #include "nsContentUtils.h"
  14
  15 nsAutoLayoutPhase::nsAutoLayoutPhase(nsPresContext* aPresContext,
  16                                      nsLayoutPhase aPhase)
  17     : mPresContext(aPresContext), mPhase(aPhase), mCount(0) {
  18   Enter();
  19 }
  20
  21 nsAutoLayoutPhase::~nsAutoLayoutPhase() {
  22   Exit();
  23   MOZ_ASSERT(mCount == 0, "imbalanced");
  24 }
  25
  26 void nsAutoLayoutPhase::Enter() {
  27   switch (mPhase) {
  28     case nsLayoutPhase::Paint:
  29       MOZ_ASSERT(mPresContext->mLayoutPhaseCount[nsLayoutPhase::Paint] == 0,
  30                  "recurring into paint");
  31       MOZ_ASSERT(
  32           mPresContext->mLayoutPhaseCount[nsLayoutPhase::DisplayListBuilding] ==
  33               0,
  34           "recurring into paint from display list building");
  35       MOZ_ASSERT(mPresContext->mLayoutPhaseCount[nsLayoutPhase::Reflow] == 0,
  36                  "painting in the middle of reflow");
  37       MOZ_ASSERT(mPresContext->mLayoutPhaseCount[nsLayoutPhase::FrameC] == 0,
  38                  "painting in the middle of frame construction");
  39       break;
  40     case nsLayoutPhase::DisplayListBuilding:
  41       // It's fine and expected to be in a paint here.
  42       MOZ_ASSERT(
  43           mPresContext->mLayoutPhaseCount[nsLayoutPhase::DisplayListBuilding] ==
  44               0,
  45           "recurring into display list building");
  46       MOZ_ASSERT(mPresContext->mLayoutPhaseCount[nsLayoutPhase::Reflow] == 0,
  47                  "display list building in the middle of reflow");
  48       MOZ_ASSERT(mPresContext->mLayoutPhaseCount[nsLayoutPhase::FrameC] == 0,
  49                  "display list building in the middle of frame construction");
  50       break;
  51     case nsLayoutPhase::Reflow:
  52       MOZ_ASSERT(mPresContext->mLayoutPhaseCount[nsLayoutPhase::Paint] == 0,
  53                  "reflowing in the middle of a paint");
  54       MOZ_ASSERT(
  55           mPresContext->mLayoutPhaseCount[nsLayoutPhase::DisplayListBuilding] ==
  56               0,
  57           "reflowing in the middle of a display list building");
  58       MOZ_ASSERT(mPresContext->mLayoutPhaseCount[nsLayoutPhase::Reflow] == 0,
  59                  "recurring into reflow");
  60       MOZ_ASSERT(mPresContext->mLayoutPhaseCount[nsLayoutPhase::FrameC] == 0,
  61                  "reflowing in the middle of frame construction");
  62       break;
  63     case nsLayoutPhase::FrameC:
  64       MOZ_ASSERT(mPresContext->mLayoutPhaseCount[nsLayoutPhase::Paint] == 0,
  65                  "constructing frames in the middle of a paint");
  66       MOZ_ASSERT(
  67           mPresContext->mLayoutPhaseCount[nsLayoutPhase::DisplayListBuilding] ==
  68               0,
  69           "constructing frames in the middle of a display list building");
  70       MOZ_ASSERT(mPresContext->mLayoutPhaseCount[nsLayoutPhase::Reflow] == 0,
  71                  "constructing frames in the middle of reflow");
  72       MOZ_ASSERT(mPresContext->mLayoutPhaseCount[nsLayoutPhase::FrameC] == 0,
  73                  "recurring into frame construction");
  74       MOZ_ASSERT(!nsContentUtils::IsSafeToRunScript(),
  75                  "constructing frames and scripts are not blocked");
  76       break;
  77     case nsLayoutPhase::COUNT:
  78       break;
  79   }
  80
  81   ++(mPresContext->mLayoutPhaseCount[mPhase]);
  82   ++mCount;
  83 }
  84
  85 void nsAutoLayoutPhase::Exit() {
  86   MOZ_ASSERT(mCount > 0 && mPresContext->mLayoutPhaseCount[mPhase] > 0,
  87              "imbalanced");
  88   --(mPresContext->mLayoutPhaseCount[mPhase]);
  89   --mCount;
  90 }