From 88f682a5d58a88e0afe1af0c8d861e26ecd788ec Mon Sep 17 00:00:00 2001
From: Anthony Ramine <n.oxyde@gmail.com>
Date: Thu, 20 Apr 2017 12:54:36 +0200
Subject: [PATCH] Properly parse alignment shorthands (fixes #16391)

---
 .../properties/shorthand/position.mako.rs     | 18 ++++++++++++++
 components/style/values/specified/align.rs    | 24 +++++++++++++++++++
 2 files changed, 42 insertions(+)

diff --git a/components/style/properties/shorthand/position.mako.rs b/components/style/properties/shorthand/position.mako.rs
index e653365273e..bd43b4f2155 100644
--- a/components/style/properties/shorthand/position.mako.rs
+++ b/components/style/properties/shorthand/position.mako.rs
@@ -249,8 +249,14 @@
 
     pub fn parse_value(context: &ParserContext, input: &mut Parser) -> Result<Longhands, ()> {
         let align = align_content::parse(context, input)?;
+        if align.has_extra_flags() {
+            return Err(());
+        }
         let justify = input.try(|input| justify_content::parse(context, input))
                            .unwrap_or(justify_content::SpecifiedValue::from(align));
+        if justify.has_extra_flags() {
+            return Err(());
+        }
 
         Ok(Longhands {
             align_content: align,
@@ -279,7 +285,13 @@
 
     pub fn parse_value(context: &ParserContext, input: &mut Parser) -> Result<Longhands, ()> {
         let align = AlignJustifySelf::parse(context, input)?;
+        if align.has_extra_flags() {
+            return Err(());
+        }
         let justify = input.try(|input| AlignJustifySelf::parse(context, input)).unwrap_or(align.clone());
+        if justify.has_extra_flags() {
+            return Err(());
+        }
 
         Ok(Longhands {
             align_self: align,
@@ -314,8 +326,14 @@
 
     pub fn parse_value(context: &ParserContext, input: &mut Parser) -> Result<Longhands, ()> {
         let align = AlignItems::parse(context, input)?;
+        if align.has_extra_flags() {
+            return Err(());
+        }
         let justify = input.try(|input| JustifyItems::parse(context, input))
                            .unwrap_or(JustifyItems::from(align));
+        if justify.has_extra_flags() {
+            return Err(());
+        }
 
         Ok(Longhands {
             align_items: align,
diff --git a/components/style/values/specified/align.rs b/components/style/values/specified/align.rs
index d62a0bbd7e4..cafbe969538 100644
--- a/components/style/values/specified/align.rs
+++ b/components/style/values/specified/align.rs
@@ -155,6 +155,12 @@ impl AlignJustifyContent {
         AlignFlags::from_bits((self.0 >> ALIGN_ALL_SHIFT) as u8)
             .expect("AlignJustifyContent must contain valid flags")
     }
+
+    /// Whether this value has extra flags.
+    #[inline]
+    pub fn has_extra_flags(self) -> bool {
+        self.primary().intersects(ALIGN_FLAG_BITS) || self.fallback().intersects(ALIGN_FLAG_BITS)
+    }
 }
 
 impl ToCss for AlignJustifyContent {
@@ -213,6 +219,12 @@ impl AlignJustifySelf {
     pub fn auto() -> Self {
         AlignJustifySelf(ALIGN_AUTO)
     }
+
+    /// Whether this value has extra flags.
+    #[inline]
+    pub fn has_extra_flags(self) -> bool {
+        self.0.intersects(ALIGN_FLAG_BITS)
+    }
 }
 
 no_viewport_percentage!(AlignJustifySelf);
@@ -251,6 +263,12 @@ impl AlignItems {
     pub fn normal() -> Self {
         AlignItems(ALIGN_NORMAL)
     }
+
+    /// Whether this value has extra flags.
+    #[inline]
+    pub fn has_extra_flags(self) -> bool {
+        self.0.intersects(ALIGN_FLAG_BITS)
+    }
 }
 
 no_viewport_percentage!(AlignItems);
@@ -289,6 +307,12 @@ impl JustifyItems {
     pub fn auto() -> Self {
         JustifyItems(ALIGN_AUTO)
     }
+
+    /// Whether this value has extra flags.
+    #[inline]
+    pub fn has_extra_flags(self) -> bool {
+        self.0.intersects(ALIGN_FLAG_BITS)
+    }
 }
 
 no_viewport_percentage!(JustifyItems);