Bug 1398963 part 7: Add an about:config flag to optionally emulate -moz-box with flexbox. r?mats
This feature is intended to help Firefox frontend developers experiment with
replacing XUL content with modern flexbox. We might also eventually use
this emulation to *actually* render most or all of our legacy XUL UI.
MozReview-Commit-ID: 3g2W9o3t23H
--- a/layout/base/nsCSSFrameConstructor.cpp
+++ b/layout/base/nsCSSFrameConstructor.cpp
@@ -86,16 +86,17 @@
#include "mozilla/dom/Element.h"
#include "mozilla/dom/ElementInlines.h"
#include "nsAutoLayoutPhase.h"
#include "nsStyleStructInlines.h"
#include "nsPageContentFrame.h"
#include "mozilla/GeckoStyleContext.h"
#include "mozilla/RestyleManager.h"
#include "mozilla/RestyleManagerInlines.h"
+#include "mozilla/StylePrefs.h"
#include "StickyScrollContainer.h"
#include "nsFieldSetFrame.h"
#include "nsInlineFrame.h"
#include "nsBlockFrame.h"
#include "nsCanvasFrame.h"
#include "nsFirstLetterFrame.h"
#include "nsGfxScrollFrame.h"
#include "nsPageFrame.h"
@@ -2683,17 +2684,19 @@ nsCSSFrameConstructor::ConstructDocEleme
nsFrameItems frameItems;
contentFrame = static_cast<nsContainerFrame*>(
ConstructOuterSVG(state, item, mDocElementContainingBlock,
styleContext->StyleDisplay(),
frameItems));
newFrame = frameItems.FirstChild();
NS_ASSERTION(frameItems.OnlyChild(), "multiple root element frames");
} else if (display->mDisplay == StyleDisplay::Flex ||
- display->mDisplay == StyleDisplay::WebkitBox) {
+ display->mDisplay == StyleDisplay::WebkitBox ||
+ (StylePrefs::sEmulateMozBoxWithFlex &&
+ display->mDisplay == StyleDisplay::MozBox)) {
contentFrame = NS_NewFlexContainerFrame(mPresShell, styleContext);
InitAndRestoreFrame(state, aDocElement, mDocElementContainingBlock,
contentFrame);
newFrame = contentFrame;
processChildren = true;
newFrame->AddStateBits(NS_FRAME_CAN_HAVE_ABSPOS_CHILDREN);
if (display->IsAbsPosContainingBlock(newFrame)) {
@@ -4392,18 +4395,20 @@ nsCSSFrameConstructor::GetAnonymousConte
}
return NS_OK;
}
static
bool IsXULDisplayType(const nsStyleDisplay* aDisplay)
{
- if (aDisplay->mDisplay == StyleDisplay::MozInlineBox ||
- aDisplay->mDisplay == StyleDisplay::MozBox) {
+ // -moz-{inline-}box is XUL, unless we're emulating it with flexbox.
+ if (!StylePrefs::sEmulateMozBoxWithFlex &&
+ (aDisplay->mDisplay == StyleDisplay::MozInlineBox ||
+ aDisplay->mDisplay == StyleDisplay::MozBox)) {
return true;
}
#ifdef MOZ_XUL
return (aDisplay->mDisplay == StyleDisplay::MozInlineGrid ||
aDisplay->mDisplay == StyleDisplay::MozInlineStack ||
aDisplay->mDisplay == StyleDisplay::MozGrid ||
aDisplay->mDisplay == StyleDisplay::MozStack ||
@@ -4643,16 +4648,27 @@ nsCSSFrameConstructor::FindXULDisplayDat
FCDATA_SKIP_ABSPOS_PUSH, NS_NewMenuPopupFrame))
#endif /* MOZ_XUL */
};
if (aDisplay->mDisplay < StyleDisplay::MozBox) {
return nullptr;
}
+ // If we're emulating -moz-box with flexbox, then treat it as non-XUL and
+ // return null (except for scrollcorners which have to be XUL becuase their
+ // parent reflows them with BoxReflow() which means they have to get
+ // actual-XUL frames).
+ if (StylePrefs::sEmulateMozBoxWithFlex &&
+ aElement && !aElement->IsXULElement(nsGkAtoms::scrollcorner) &&
+ (aDisplay->mDisplay == StyleDisplay::MozBox ||
+ aDisplay->mDisplay == StyleDisplay::MozInlineBox)) {
+ return nullptr;
+ }
+
MOZ_ASSERT(aDisplay->mDisplay <= StyleDisplay::MozPopup,
"Someone added a new display value?");
const FrameConstructionDataByDisplay& data =
sXULDisplayData[size_t(aDisplay->mDisplay) - size_t(StyleDisplay::MozBox)];
MOZ_ASSERT(aDisplay->mDisplay == data.mDisplay,
"Did someone mess with the order?");
@@ -4869,17 +4885,19 @@ nsCSSFrameConstructor::FindDisplayData(c
return &sNonScrollableBlockData[suppressScrollFrame][caption];
}
// If this is for a <body> node and we've propagated the scroll-frame to the
// viewport, we need to make sure not to add another layer of scrollbars, so
// we use a different FCData struct without FCDATA_MAY_NEED_SCROLLFRAME.
if (propagatedScrollToViewport && aDisplay->IsScrollableOverflow()) {
if (aDisplay->mDisplay == StyleDisplay::Flex ||
- aDisplay->mDisplay == StyleDisplay::WebkitBox) {
+ aDisplay->mDisplay == StyleDisplay::WebkitBox ||
+ (StylePrefs::sEmulateMozBoxWithFlex &&
+ aDisplay->mDisplay == StyleDisplay::MozBox)) {
static const FrameConstructionData sNonScrollableFlexData =
FCDATA_DECL(0, NS_NewFlexContainerFrame);
return &sNonScrollableFlexData;
}
if (aDisplay->mDisplay == StyleDisplay::Grid) {
static const FrameConstructionData sNonScrollableGridData =
FCDATA_DECL(0, NS_NewGridContainerFrame);
return &sNonScrollableGridData;
@@ -4963,20 +4981,27 @@ nsCSSFrameConstructor::FindDisplayData(c
FCDATA_DECL(FCDATA_DESIRED_PARENT_TYPE_TO_BITS(eTypeRuby),
NS_NewRubyTextContainerFrame)),
FCDATA_FOR_DISPLAY(StyleDisplay::Contents,
FULL_CTOR_FCDATA(FCDATA_IS_CONTENTS, nullptr/*never called*/)),
FCDATA_FOR_DISPLAY(StyleDisplay::WebkitBox,
FCDATA_DECL(FCDATA_MAY_NEED_SCROLLFRAME, NS_NewFlexContainerFrame)),
FCDATA_FOR_DISPLAY(StyleDisplay::WebkitInlineBox,
FCDATA_DECL(FCDATA_MAY_NEED_SCROLLFRAME, NS_NewFlexContainerFrame)),
+ FCDATA_FOR_DISPLAY(StyleDisplay::MozBox,
+ FCDATA_DECL(FCDATA_MAY_NEED_SCROLLFRAME, NS_NewFlexContainerFrame)),
+ FCDATA_FOR_DISPLAY(StyleDisplay::MozInlineBox,
+ FCDATA_DECL(FCDATA_MAY_NEED_SCROLLFRAME, NS_NewFlexContainerFrame)),
};
- static_assert(ArrayLength(sDisplayData) == size_t(StyleDisplay::WebkitInlineBox) + 1,
+ static_assert(ArrayLength(sDisplayData) == size_t(StyleDisplay::MozInlineBox) + 1,
"Be sure to update sDisplayData if you touch StyleDisplay");
-
+ MOZ_ASSERT(StylePrefs::sEmulateMozBoxWithFlex ||
+ (aDisplay->mDisplay != StyleDisplay::MozBox &&
+ aDisplay->mDisplay != StyleDisplay::MozInlineBox),
+ "-moz-{inline-}box as XUL should have already been handled");
MOZ_ASSERT(size_t(aDisplay->mDisplay) < ArrayLength(sDisplayData),
"XUL display data should have already been handled");
// See the mDisplay fixup code in nsRuleNode::ComputeDisplayData.
MOZ_ASSERT(aDisplay->mDisplay != StyleDisplay::Contents ||
!aElement->IsRootOfNativeAnonymousSubtree(),
"display:contents on anonymous content is unsupported");
--- a/layout/style/StylePrefs.cpp
+++ b/layout/style/StylePrefs.cpp
@@ -16,16 +16,17 @@ bool StylePrefs::sWebkitPrefixedAliasesE
bool StylePrefs::sWebkitDevicePixelRatioEnabled;
bool StylePrefs::sMozGradientsEnabled;
bool StylePrefs::sControlCharVisibility;
bool StylePrefs::sFramesTimingFunctionEnabled;
bool StylePrefs::sUnprefixedFullscreenApiEnabled;
bool StylePrefs::sVisitedLinksEnabled;
bool StylePrefs::sMozDocumentEnabledInContent;
bool StylePrefs::sGridTemplateSubgridValueEnabled;
+bool StylePrefs::sEmulateMozBoxWithFlex;
/* static */ void
StylePrefs::Init()
{
Preferences::AddBoolVarCache(&sFontDisplayEnabled,
"layout.css.font-display.enabled");
Preferences::AddBoolVarCache(&sOpentypeSVGEnabled,
"gfx.font_rendering.opentype_svg.enabled");
@@ -42,11 +43,18 @@ StylePrefs::Init()
Preferences::AddBoolVarCache(&sUnprefixedFullscreenApiEnabled,
"full-screen-api.unprefix.enabled");
Preferences::AddBoolVarCache(&sVisitedLinksEnabled,
"layout.css.visited_links_enabled");
Preferences::AddBoolVarCache(&sMozDocumentEnabledInContent,
"layout.css.moz-document.content.enabled");
Preferences::AddBoolVarCache(&sGridTemplateSubgridValueEnabled,
"layout.css.grid-template-subgrid-value.enabled");
+
+ // Only honor layout.css.emulate-moz-box-with-flex in prerelease builds.
+ // (In release builds, sEmulateMozBoxWithFlex will be implicitly false.)
+#ifndef RELEASE_OR_BETA
+ Preferences::AddBoolVarCache(&sEmulateMozBoxWithFlex,
+ "layout.css.emulate-moz-box-with-flex");
+#endif
}
} // namespace mozilla
--- a/layout/style/StylePrefs.h
+++ b/layout/style/StylePrefs.h
@@ -19,15 +19,16 @@ struct StylePrefs
static bool sWebkitDevicePixelRatioEnabled;
static bool sMozGradientsEnabled;
static bool sControlCharVisibility;
static bool sFramesTimingFunctionEnabled;
static bool sUnprefixedFullscreenApiEnabled;
static bool sVisitedLinksEnabled;
static bool sMozDocumentEnabledInContent;
static bool sGridTemplateSubgridValueEnabled;
+ static bool sEmulateMozBoxWithFlex;
static void Init();
};
} // namespace mozilla
#endif // mozilla_StylePrefs_h
--- a/modules/libpref/init/all.js
+++ b/modules/libpref/init/all.js
@@ -2966,16 +2966,23 @@ pref("layout.css.font-variations.enabled
// Is support for the frames() timing function enabled?
#ifdef RELEASE_OR_BETA
pref("layout.css.frames-timing.enabled", false);
#else
pref("layout.css.frames-timing.enabled", true);
#endif
+// Are we emulating -moz-{inline}-box layout using CSS flexbox?
+// (This pref only takes effect in prerelease builds, so we only
+// bother specifying a default in prerelease builds as well.)
+#ifndef RELEASE_OR_BETA
+pref("layout.css.emulate-moz-box-with-flex", false);
+#endif
+
// Are sets of prefixed properties supported?
pref("layout.css.prefixes.border-image", true);
pref("layout.css.prefixes.transforms", true);
pref("layout.css.prefixes.transitions", true);
pref("layout.css.prefixes.animations", true);
pref("layout.css.prefixes.box-sizing", true);
pref("layout.css.prefixes.font-features", true);
