Attachment 338881 Details for Bug 185032 – Patch

[patch] Patch

bug-185032-20180426095057.patch (text/plain), 21.00 KB, created by zalan on 2018-04-26 09:50:58 PDT

(hide)

Description:

Filename:

MIME Type:

Creator: zalan

Created: 2018-04-26 09:50:58 PDT

Size: 21.00 KB

patch

obsolete

>Subversion Revision: 231038
>diff --git a/Source/WebCore/ChangeLog b/Source/WebCore/ChangeLog
>index af46292fc656ab02433503336226c32a680599eb..3dff51b079be543753d82ec36b5e24e1c5a32107 100644
>--- a/Source/WebCore/ChangeLog
>+++ b/Source/WebCore/ChangeLog
>@@ -1,3 +1,55 @@
>+2018-04-26  Zalan Bujtas  <zalan@apple.com>
>+
>+        [LFC] Formatting contexts should create floating states.
>+        https://bugs.webkit.org/show_bug.cgi?id=185032
>+
>+        Reviewed by NOBODY (OOPS!).
>+
>+        This patch implements the logic for sharing floating states across multiple formatting contexts.
>+        At this point this is mostly about inline formatting contexts. They either create a new floating state
>+        or inherit it from the parent formatting context.
>+
>+        * layout/FloatingState.cpp:
>+        (WebCore::Layout::FloatingState::FloatingState):
>+        * layout/FloatingState.h:
>+        (WebCore::Layout::FloatingState::create):
>+        * layout/FormattingContext.cpp:
>+        (WebCore::Layout::FormattingContext::FormattingContext):
>+        * layout/FormattingContext.h:
>+        (WebCore::Layout::FormattingContext::layoutContext const):
>+        * layout/FormattingState.cpp:
>+        (WebCore::Layout::FormattingState::FormattingState):
>+        * layout/FormattingState.h:
>+        (WebCore::Layout::FormattingState::floatingState const):
>+        * layout/LayoutContext.cpp:
>+        (WebCore::Layout::LayoutContext::updateLayout):
>+        (WebCore::Layout::LayoutContext::formattingStateForBox const):
>+        (WebCore::Layout::LayoutContext::establishedFormattingState):
>+        (WebCore::Layout::LayoutContext::formattingContext):
>+        (WebCore::Layout::LayoutContext::formattingState): Deleted.
>+        * layout/LayoutContext.h:
>+        * layout/blockformatting/BlockFormattingContext.cpp:
>+        (WebCore::Layout::BlockFormattingContext::BlockFormattingContext):
>+        (WebCore::Layout::BlockFormattingContext::createFormattingState const):
>+        (WebCore::Layout::BlockFormattingContext::createOrFindFloatingState const):
>+        (WebCore::Layout::BlockFormattingContext::formattingState const): Deleted.
>+        * layout/blockformatting/BlockFormattingContext.h:
>+        * layout/blockformatting/BlockFormattingState.cpp:
>+        (WebCore::Layout::BlockFormattingState::BlockFormattingState):
>+        * layout/blockformatting/BlockFormattingState.h:
>+        * layout/inlineformatting/InlineFormattingContext.cpp:
>+        (WebCore::Layout::InlineFormattingContext::InlineFormattingContext):
>+        (WebCore::Layout::InlineFormattingContext::createFormattingState const):
>+        (WebCore::Layout::InlineFormattingContext::createOrFindFloatingState const):
>+        (WebCore::Layout::InlineFormattingContext::formattingState const): Deleted.
>+        * layout/inlineformatting/InlineFormattingContext.h:
>+        * layout/inlineformatting/InlineFormattingState.cpp:
>+        (WebCore::Layout::InlineFormattingState::InlineFormattingState):
>+        * layout/inlineformatting/InlineFormattingState.h:
>+        * layout/layouttree/LayoutBox.cpp:
>+        (WebCore::Layout::Box::formattingContextRoot const):
>+        * layout/layouttree/LayoutBox.h:
>+
> 2018-04-25  Zalan Bujtas  <zalan@apple.com>
> 
>         [LFC] Add support for is<> and downcast<>
>diff --git a/Source/WebCore/layout/FloatingState.cpp b/Source/WebCore/layout/FloatingState.cpp
>index 5e00ba70b9a5f57b85387ba7b0c0da053acaec36..50519a9dc89b6de534a7aeacbf400e75b18eb441 100644
>--- a/Source/WebCore/layout/FloatingState.cpp
>+++ b/Source/WebCore/layout/FloatingState.cpp
>@@ -25,3 +25,20 @@
> 
> #include "config.h"
> #include "FloatingState.h"
>+
>+#if ENABLE(LAYOUT_FORMATTING_CONTEXT)
>+
>+#include <wtf/IsoMallocInlines.h>
>+
>+namespace WebCore {
>+namespace Layout {
>+
>+WTF_MAKE_ISO_ALLOCATED_IMPL(FloatingState);
>+
>+FloatingState::FloatingState()
>+{
>+}
>+
>+}
>+}
>+#endif
>diff --git a/Source/WebCore/layout/FloatingState.h b/Source/WebCore/layout/FloatingState.h
>index cb1781b8c67fe6f3cb6d4cfdeb49f86e2533504e..6fe7e22570ffb0de26bfa02d08d2e738c9700e52 100644
>--- a/Source/WebCore/layout/FloatingState.h
>+++ b/Source/WebCore/layout/FloatingState.h
>@@ -28,6 +28,7 @@
> #if ENABLE(LAYOUT_FORMATTING_CONTEXT)
> 
> #include <wtf/IsoMalloc.h>
>+#include <wtf/Ref.h>
> 
> namespace WebCore {
> 
>@@ -36,10 +37,13 @@ namespace Layout {
> class FormattingState;
> 
> // FloatingState holds the floating boxes per formatting context.
>-class FloatingState {
>+class FloatingState : public RefCounted<FloatingState> {
>     WTF_MAKE_ISO_ALLOCATED(FloatingState);
> public:
>-    FloatingState(FormattingState& parentFormattingState);
>+    static Ref<FloatingState> create() { return adoptRef(*new FloatingState()); }
>+
>+private:
>+    FloatingState();
> };
> 
> }
>diff --git a/Source/WebCore/layout/FormattingContext.cpp b/Source/WebCore/layout/FormattingContext.cpp
>index 9855bad4295e7a9b5c8bdf5f2c87d3f41b14d4ec..b58a1f9ab91421e99246d32f6b5f6493aaef5145 100644
>--- a/Source/WebCore/layout/FormattingContext.cpp
>+++ b/Source/WebCore/layout/FormattingContext.cpp
>@@ -35,8 +35,9 @@ namespace Layout {
> 
> WTF_MAKE_ISO_ALLOCATED_IMPL(FormattingContext);
> 
>-FormattingContext::FormattingContext(Box& formattingContextRoot)
>+FormattingContext::FormattingContext(Box& formattingContextRoot, LayoutContext& layoutContext)
>     : m_root(makeWeakPtr(formattingContextRoot))
>+    , m_layoutContext(layoutContext)
> {
> }
> 
>diff --git a/Source/WebCore/layout/FormattingContext.h b/Source/WebCore/layout/FormattingContext.h
>index e86cff92d2775a3057774837b294f04ee7f81d51..431d3958a2f821c1b5d9be5707f416d965a94ac2 100644
>--- a/Source/WebCore/layout/FormattingContext.h
>+++ b/Source/WebCore/layout/FormattingContext.h
>@@ -27,6 +27,7 @@
> 
> #if ENABLE(LAYOUT_FORMATTING_CONTEXT)
> 
>+#include "FloatingState.h"
> #include "LayoutUnit.h"
> #include <wtf/IsoMalloc.h>
> #include <wtf/WeakPtr.h>
>@@ -35,21 +36,24 @@ namespace WebCore {
> 
> namespace Layout {
> 
>-class FormattingState;
> class Box;
>+class FormattingState;
>+class LayoutContext;
> 
> class FormattingContext {
>     WTF_MAKE_ISO_ALLOCATED(FormattingContext);
> public:
>-    FormattingContext(Box& formattingContextRoot);
>+    FormattingContext(Box& formattingContextRoot, LayoutContext&);
>     virtual ~FormattingContext();
> 
>     virtual void layout(FormattingState&) = 0;
>-    virtual std::unique_ptr<FormattingState> formattingState() const = 0;
>+    virtual std::unique_ptr<FormattingState> createFormattingState(Ref<FloatingState>&&) const = 0;
>+    virtual Ref<FloatingState> createOrFindFloatingState() const = 0;
> 
>+protected:
>     const Box& root() const { return *m_root; }
>+    const LayoutContext& layoutContext() const { return m_layoutContext; }
> 
>-protected:
>     virtual void computeStaticPosition(const Box&) const;
>     virtual void computeInFlowPositionedPosition(const Box&) const;
>     virtual void computeOutOfFlowPosition(const Box&) const;
>@@ -64,6 +68,7 @@ protected:
> 
> private:
>     WeakPtr<Box> m_root;
>+    LayoutContext& m_layoutContext;
> };
> 
> }
>diff --git a/Source/WebCore/layout/FormattingState.cpp b/Source/WebCore/layout/FormattingState.cpp
>index 8fa0d438ccf7c53096a38db4c44afc12e410c93f..0e28e8569a949e775f5adcbcfee54f4c2f08f82a 100644
>--- a/Source/WebCore/layout/FormattingState.cpp
>+++ b/Source/WebCore/layout/FormattingState.cpp
>@@ -35,7 +35,8 @@ namespace Layout {
> 
> WTF_MAKE_ISO_ALLOCATED_IMPL(FormattingState);
> 
>-FormattingState::FormattingState()
>+FormattingState::FormattingState(Ref<FloatingState>&& floatingState)
>+    : m_floatingState(WTFMove(floatingState))
> {
> }
> 
>diff --git a/Source/WebCore/layout/FormattingState.h b/Source/WebCore/layout/FormattingState.h
>index e34c009c3c0631f42baa5b6f2f61c705efba219d..698b3c7f2cbc51dc502dfaa548a6b6d6db71ee5e 100644
>--- a/Source/WebCore/layout/FormattingState.h
>+++ b/Source/WebCore/layout/FormattingState.h
>@@ -27,6 +27,7 @@
> 
> #if ENABLE(LAYOUT_FORMATTING_CONTEXT)
> 
>+#include "FloatingState.h"
> #include <wtf/IsoMalloc.h>
> 
> namespace WebCore {
>@@ -34,18 +35,20 @@ namespace WebCore {
> namespace Layout {
> 
> class Box;
>-class FloatingState;
> class StyleDiff;
> 
> class FormattingState {
>     WTF_MAKE_ISO_ALLOCATED(FormattingState);
> public:
>-    FormattingState();
>+    FormattingState(Ref<FloatingState>&&);
> 
>-    FloatingState& floatingState();
>+    FloatingState& floatingState() const { return m_floatingState; }
> 
>     void markNeedsLayout(const Box&, StyleDiff);
>     bool needsLayout(const Box&);
>+
>+private:
>+    Ref<FloatingState> m_floatingState;
> };
> 
> }
>diff --git a/Source/WebCore/layout/LayoutContext.cpp b/Source/WebCore/layout/LayoutContext.cpp
>index 938dd2b085dce73fefb960dd2d911f2e52a35791..32f35c44e572e584abdfb49a1e6f291b2f48cda7 100644
>--- a/Source/WebCore/layout/LayoutContext.cpp
>+++ b/Source/WebCore/layout/LayoutContext.cpp
>@@ -33,6 +33,7 @@
> #include "InlineFormattingContext.h"
> #include "InlineFormattingState.h"
> #include "LayoutBox.h"
>+#include "LayoutContainer.h"
> #include <wtf/IsoMallocInlines.h>
> 
> namespace WebCore {
>@@ -48,24 +49,31 @@ LayoutContext::LayoutContext(Box& root)
> void LayoutContext::updateLayout()
> {
>     auto context = formattingContext(*m_root);
>-    auto state = formattingState(*context);
>+    auto& state = establishedFormattingState(*m_root, *context);
>     context->layout(state);
> }
> 
>-FormattingState& LayoutContext::formattingState(const FormattingContext& context)
>+FormattingState& LayoutContext::formattingStateForBox(const Box& layoutBox) const
> {
>-    return *m_formattingStates.ensure(&context.root(), [&context] {
>-        return context.formattingState();
>+    auto* root = layoutBox.formattingContextRoot();
>+    RELEASE_ASSERT(m_formattingStates.contains(root));
>+    return *m_formattingStates.get(root);
>+}
>+
>+FormattingState& LayoutContext::establishedFormattingState(Box& formattingContextRoot, const FormattingContext& context)
>+{
>+    return *m_formattingStates.ensure(&formattingContextRoot, [this, &context] {
>+        return context.createFormattingState(context.createOrFindFloatingState());
>     }).iterator->value;
> }
> 
> std::unique_ptr<FormattingContext> LayoutContext::formattingContext(Box& formattingContextRoot)
> {
>     if (formattingContextRoot.establishesBlockFormattingContext())
>-        return std::make_unique<BlockFormattingContext>(formattingContextRoot);
>+        return std::make_unique<BlockFormattingContext>(formattingContextRoot, *this);
> 
>     if (formattingContextRoot.establishesInlineFormattingContext())
>-        return std::make_unique<InlineFormattingContext>(formattingContextRoot);
>+        return std::make_unique<InlineFormattingContext>(formattingContextRoot, *this);
> 
>     ASSERT_NOT_REACHED();
>     return nullptr;
>diff --git a/Source/WebCore/layout/LayoutContext.h b/Source/WebCore/layout/LayoutContext.h
>index 15007d60a621aa64a0aa9ab4b3d3885f6945a5de..a95d596ad5717369bf3b0c2c9218e8bb6332626e 100644
>--- a/Source/WebCore/layout/LayoutContext.h
>+++ b/Source/WebCore/layout/LayoutContext.h
>@@ -60,8 +60,10 @@ public:
>     void markNeedsLayout(const Box&, StyleDiff);
>     bool needsLayout(const Box&) const;
> 
>+    FormattingState& formattingStateForBox(const Box&) const;
>+
> private:
>-    FormattingState& formattingState(const FormattingContext&);
>+    FormattingState& establishedFormattingState(Box& formattingContextRoot, const FormattingContext&);
>     std::unique_ptr<FormattingContext> formattingContext(Box& formattingContextRoot);
> 
>     WeakPtr<Box> m_root;
>diff --git a/Source/WebCore/layout/blockformatting/BlockFormattingContext.cpp b/Source/WebCore/layout/blockformatting/BlockFormattingContext.cpp
>index d37e1814bbede6d7737dbd0115fccd75f61d1ced..2ec7d27f390f9ae3e41056f0542562793a5a83cb 100644
>--- a/Source/WebCore/layout/blockformatting/BlockFormattingContext.cpp
>+++ b/Source/WebCore/layout/blockformatting/BlockFormattingContext.cpp
>@@ -29,6 +29,7 @@
> #if ENABLE(LAYOUT_FORMATTING_CONTEXT)
> 
> #include "BlockFormattingState.h"
>+#include "FloatingState.h"
> #include <wtf/IsoMallocInlines.h>
> 
> namespace WebCore {
>@@ -36,8 +37,8 @@ namespace Layout {
> 
> WTF_MAKE_ISO_ALLOCATED_IMPL(BlockFormattingContext);
> 
>-BlockFormattingContext::BlockFormattingContext(Box& formattingContextRoot)
>-    : FormattingContext(formattingContextRoot)
>+BlockFormattingContext::BlockFormattingContext(Box& formattingContextRoot, LayoutContext& layoutContext)
>+    : FormattingContext(formattingContextRoot, layoutContext)
> {
> }
> 
>@@ -45,9 +46,15 @@ void BlockFormattingContext::layout(FormattingState&)
> {
> }
> 
>-std::unique_ptr<FormattingState> BlockFormattingContext::formattingState() const
>+std::unique_ptr<FormattingState> BlockFormattingContext::createFormattingState(Ref<FloatingState>&& floatingState) const
> {
>-    return std::make_unique<BlockFormattingState>();
>+    return std::make_unique<BlockFormattingState>(WTFMove(floatingState));
>+}
>+
>+Ref<FloatingState> BlockFormattingContext::createOrFindFloatingState() const
>+{
>+    // Block formatting context always establishes a new floating state.
>+    return FloatingState::create();
> }
> 
> void BlockFormattingContext::computeStaticPosition(const Box&) const
>diff --git a/Source/WebCore/layout/blockformatting/BlockFormattingContext.h b/Source/WebCore/layout/blockformatting/BlockFormattingContext.h
>index f12e7e762d53341ea26ccde7a1d81be9c9fdbbfa..9821f50ccf07182266210f5bb4fb363e8dfaafb4 100644
>--- a/Source/WebCore/layout/blockformatting/BlockFormattingContext.h
>+++ b/Source/WebCore/layout/blockformatting/BlockFormattingContext.h
>@@ -43,10 +43,11 @@ class Box;
> class BlockFormattingContext : public FormattingContext {
>     WTF_MAKE_ISO_ALLOCATED(BlockFormattingContext);
> public:
>-    BlockFormattingContext(Box& formattingContextRoot);
>+    BlockFormattingContext(Box& formattingContextRoot, LayoutContext&);
> 
>     void layout(FormattingState&) override;
>-    std::unique_ptr<FormattingState> formattingState() const override;
>+    std::unique_ptr<FormattingState> createFormattingState(Ref<FloatingState>&&) const override;
>+    Ref<FloatingState> createOrFindFloatingState() const override;
> 
> protected:
>     void computeStaticPosition(const Box&) const override;
>diff --git a/Source/WebCore/layout/blockformatting/BlockFormattingState.cpp b/Source/WebCore/layout/blockformatting/BlockFormattingState.cpp
>index 244d8254acef7f1c3291de976204af82de57fe2c..95a8a0bd3f4aafc44193075a3c853ce18ac33749 100644
>--- a/Source/WebCore/layout/blockformatting/BlockFormattingState.cpp
>+++ b/Source/WebCore/layout/blockformatting/BlockFormattingState.cpp
>@@ -35,8 +35,8 @@ namespace Layout {
> 
> WTF_MAKE_ISO_ALLOCATED_IMPL(BlockFormattingState);
> 
>-BlockFormattingState::BlockFormattingState()
>-    : FormattingState()
>+BlockFormattingState::BlockFormattingState(Ref<FloatingState>&& floatingState)
>+    : FormattingState(WTFMove(floatingState))
> {
> }
> 
>diff --git a/Source/WebCore/layout/blockformatting/BlockFormattingState.h b/Source/WebCore/layout/blockformatting/BlockFormattingState.h
>index 5485bda2f68ddeacc14e28bd5c95f1bc74c5633f..6202310888461f38c704e60a959d855e54813232 100644
>--- a/Source/WebCore/layout/blockformatting/BlockFormattingState.h
>+++ b/Source/WebCore/layout/blockformatting/BlockFormattingState.h
>@@ -38,7 +38,7 @@ namespace Layout {
> class BlockFormattingState : public FormattingState {
>     WTF_MAKE_ISO_ALLOCATED(BlockFormattingState);
> public:
>-    BlockFormattingState();
>+    BlockFormattingState(Ref<FloatingState>&&);
> };
> 
> }
>diff --git a/Source/WebCore/layout/inlineformatting/InlineFormattingContext.cpp b/Source/WebCore/layout/inlineformatting/InlineFormattingContext.cpp
>index 7d1b76403d9cb43977f35d917bc718d244bb5af6..bd1759e8fb9c7fecb3a4d9f4383bd00cc54ff8cf 100644
>--- a/Source/WebCore/layout/inlineformatting/InlineFormattingContext.cpp
>+++ b/Source/WebCore/layout/inlineformatting/InlineFormattingContext.cpp
>@@ -28,7 +28,10 @@
> 
> #if ENABLE(LAYOUT_FORMATTING_CONTEXT)
> 
>+#include "FloatingState.h"
> #include "InlineFormattingState.h"
>+#include "LayoutBox.h"
>+#include "LayoutContext.h"
> #include <wtf/IsoMallocInlines.h>
> 
> namespace WebCore {
>@@ -36,8 +39,8 @@ namespace Layout {
> 
> WTF_MAKE_ISO_ALLOCATED_IMPL(InlineFormattingContext);
> 
>-InlineFormattingContext::InlineFormattingContext(Box& formattingContextRoot)
>-    : FormattingContext(formattingContextRoot)
>+InlineFormattingContext::InlineFormattingContext(Box& formattingContextRoot, LayoutContext& layoutContext)
>+    : FormattingContext(formattingContextRoot, layoutContext)
> {
> }
> 
>@@ -45,9 +48,22 @@ void InlineFormattingContext::layout(FormattingState&)
> {
> }
> 
>-std::unique_ptr<FormattingState> InlineFormattingContext::formattingState() const
>+std::unique_ptr<FormattingState> InlineFormattingContext::createFormattingState(Ref<FloatingState>&& floatingState) const
> {
>-    return std::make_unique<InlineFormattingState>();
>+    return std::make_unique<InlineFormattingState>(WTFMove(floatingState));
>+}
>+
>+Ref<FloatingState> InlineFormattingContext::createOrFindFloatingState() const
>+{
>+    // If the block container box that initiates this inline formatting context also establishes a block context, the floats outside of the formatting root
>+    // should not interfere with the content inside.
>+    // <div style="float: left"></div><div style="overflow: hidden"> <- is a non-intrusive float, because overflow: hidden triggers new block formatting context.</div>
>+    if (root().establishesBlockFormattingContext())
>+        return FloatingState::create();
>+    // Otherwise, the formatting context inherits the floats from the parent formatting context.
>+    // Find the formatting state in which this formatting root lives, not the one it creates (this) and use its floating state.
>+    auto& formattingState = layoutContext().formattingStateForBox(root());
>+    return formattingState.floatingState();
> }
> 
> }
>diff --git a/Source/WebCore/layout/inlineformatting/InlineFormattingContext.h b/Source/WebCore/layout/inlineformatting/InlineFormattingContext.h
>index 6026060e9ec4e787f230501649a2dbe898d27125..b3fa4dffe6c95b7926b0d332ed67bbdf710aaf6a 100644
>--- a/Source/WebCore/layout/inlineformatting/InlineFormattingContext.h
>+++ b/Source/WebCore/layout/inlineformatting/InlineFormattingContext.h
>@@ -41,10 +41,11 @@ class InlineFormattingState;
> class InlineFormattingContext : public FormattingContext {
>     WTF_MAKE_ISO_ALLOCATED(InlineFormattingContext);
> public:
>-    InlineFormattingContext(Box& formattingContextRoot);
>+    InlineFormattingContext(Box& formattingContextRoot, LayoutContext&);
> 
>     void layout(FormattingState&) override;
>-    std::unique_ptr<FormattingState> formattingState() const override;
>+    std::unique_ptr<FormattingState> createFormattingState(Ref<FloatingState>&&) const override;
>+    Ref<FloatingState> createOrFindFloatingState() const override;
> };
> 
> }
>diff --git a/Source/WebCore/layout/inlineformatting/InlineFormattingState.cpp b/Source/WebCore/layout/inlineformatting/InlineFormattingState.cpp
>index 930a88504192b2f75ac52fd6ec1a8c8a26065640..99970d1d8ca85cbb58c10a1bcc6f4562365666bb 100644
>--- a/Source/WebCore/layout/inlineformatting/InlineFormattingState.cpp
>+++ b/Source/WebCore/layout/inlineformatting/InlineFormattingState.cpp
>@@ -35,8 +35,8 @@ namespace Layout {
> 
> WTF_MAKE_ISO_ALLOCATED_IMPL(InlineFormattingState);
> 
>-InlineFormattingState::InlineFormattingState()
>-    : FormattingState()
>+InlineFormattingState::InlineFormattingState(Ref<FloatingState>&& floatingState)
>+    : FormattingState(WTFMove(floatingState))
> {
> }
> 
>diff --git a/Source/WebCore/layout/inlineformatting/InlineFormattingState.h b/Source/WebCore/layout/inlineformatting/InlineFormattingState.h
>index ed9bcdadc7844f17e0e7ea861734d05b31ee55bc..c7b5d7b3296f7b2b325ae481490ffc63e0ed25cd 100644
>--- a/Source/WebCore/layout/inlineformatting/InlineFormattingState.h
>+++ b/Source/WebCore/layout/inlineformatting/InlineFormattingState.h
>@@ -38,7 +38,7 @@ namespace Layout {
> class InlineFormattingState : public FormattingState {
>     WTF_MAKE_ISO_ALLOCATED(InlineFormattingState);
> public:
>-    InlineFormattingState();
>+    InlineFormattingState(Ref<FloatingState>&&);
> };
> 
> }
>diff --git a/Source/WebCore/layout/layouttree/LayoutBox.cpp b/Source/WebCore/layout/layouttree/LayoutBox.cpp
>index dec0d3529cded90cc5b843a74586e36b52c90a68..b8acc028d8a5b12bfc2416f61ca41e36b00e813a 100644
>--- a/Source/WebCore/layout/layouttree/LayoutBox.cpp
>+++ b/Source/WebCore/layout/layouttree/LayoutBox.cpp
>@@ -128,6 +128,18 @@ const Container* Box::containingBlock() const
>     return nullptr;
> }
> 
>+const Container* Box::formattingContextRoot() const
>+{
>+    for (auto* ancestor = containingBlock(); ancestor; ancestor = ancestor->containingBlock()) {
>+        if (ancestor->establishesFormattingContext())
>+            return ancestor;
>+    }
>+
>+    // Initial containing block always establishes a formatting context.
>+    ASSERT_NOT_REACHED();
>+    return nullptr;
>+}
>+
> bool Box::isDescendantOf(Container& container) const
> {
>     auto* ancestor = parent();
>diff --git a/Source/WebCore/layout/layouttree/LayoutBox.h b/Source/WebCore/layout/layouttree/LayoutBox.h
>index d3124a5747e95db00390ed63adfd06151d9e3cb7..561d4246f90e96342a59d93c365a31aac3def6c5 100644
>--- a/Source/WebCore/layout/layouttree/LayoutBox.h
>+++ b/Source/WebCore/layout/layouttree/LayoutBox.h
>@@ -64,6 +64,7 @@ public:
>     bool isFloatingOrOutOfFlowPositioned() const { return isFloatingPositioned() || isOutOfFlowPositioned(); }
> 
>     const Container* containingBlock() const;
>+    const Container* formattingContextRoot() const;
>     bool isDescendantOf(Container&) const;
> 
>     bool isAnonymous() const { return m_isAnonymous; }

Flags:

koivisto: review+
ews-watchlist: commit-queue-

Actions: View | Formatted Diff | Diff

Attachments on bug 185032: 338881 | 338950