style: Use enums for text-align / text-align-last.

This also fixes some backwards logic in nsBlockFrame::ReflowDirtyLines, and adds
some static assertions to nsGenericHTMLElement that almost cause a very subtle
bug.

Depends on D63792

Differential Revision: https://phabricator.services.mozilla.com/D63793

components/style/gecko/conversions.rs

@@ -10,10 +10,9 @@
 
 #![allow(unsafe_code)]
 
-use crate::gecko_bindings::structs::{self, Matrix4x4Components, nsresult};
+use crate::gecko_bindings::structs::{Matrix4x4Components, nsresult};
 use crate::stylesheets::RulesMutateError;
 use crate::values::computed::transform::Matrix3D;
-use crate::values::computed::TextAlign;
 
 impl From<RulesMutateError> for nsresult {
     fn from(other: RulesMutateError) -> Self {
@@ -26,39 +25,6 @@ impl From<RulesMutateError> for nsresult {
     }
 }
 
-impl TextAlign {
-    /// Obtain a specified value from a Gecko keyword value
-    ///
-    /// Intended for use with presentation attributes, not style structs
-    pub fn from_gecko_keyword(kw: u32) -> Self {
-        match kw {
-            structs::NS_STYLE_TEXT_ALIGN_LEFT => TextAlign::Left,
-            structs::NS_STYLE_TEXT_ALIGN_RIGHT => TextAlign::Right,
-            structs::NS_STYLE_TEXT_ALIGN_CENTER => TextAlign::Center,
-            structs::NS_STYLE_TEXT_ALIGN_JUSTIFY => TextAlign::Justify,
-            structs::NS_STYLE_TEXT_ALIGN_MOZ_LEFT => TextAlign::MozLeft,
-            structs::NS_STYLE_TEXT_ALIGN_MOZ_RIGHT => TextAlign::MozRight,
-            structs::NS_STYLE_TEXT_ALIGN_MOZ_CENTER => TextAlign::MozCenter,
-            structs::NS_STYLE_TEXT_ALIGN_CHAR => TextAlign::Char,
-            structs::NS_STYLE_TEXT_ALIGN_END => TextAlign::End,
-            _ => panic!("Found unexpected value in style struct for text-align property"),
-        }
-    }
-}
-
-/// Convert to String from given chars pointer.
-pub unsafe fn string_from_chars_pointer(p: *const u16) -> String {
-    use std::slice;
-    let mut length = 0;
-    let mut iter = p;
-    while *iter != 0 {
-        length += 1;
-        iter = iter.offset(1);
-    }
-    let char_vec = slice::from_raw_parts(p, length as usize);
-    String::from_utf16_lossy(char_vec)
-}
-
 impl<'a> From<&'a Matrix4x4Components> for Matrix3D {
     fn from(m: &'a Matrix4x4Components) -> Matrix3D {
         Matrix3D {

components/style/properties/data.py

@@ -382,6 +382,7 @@ class Longhand(object):
                 "ScrollSnapStrictness",
                 "ScrollSnapType",
                 "TextAlign",
+                "TextAlignLast",
                 "TextDecorationLine",
                 "TextEmphasisPosition",
                 "TextTransform",

components/style/properties/gecko.mako.rs

@@ -2016,16 +2016,9 @@ fn static_assert() {
 
 
 <%self:impl_trait style_struct_name="InheritedText"
-                  skip_longhands="text-align -webkit-text-stroke-width">
+                  skip_longhands="-webkit-text-stroke-width">
-
-    <% text_align_keyword = Keyword("text-align",
-                                    "start end left right center justify -moz-center -moz-left -moz-right char",
-                                    gecko_strip_moz_prefix=False) %>
-    ${impl_keyword('text_align', 'mTextAlign', text_align_keyword)}
-
     ${impl_non_negative_length('_webkit_text_stroke_width',
                                'mWebkitTextStrokeWidth')}
-
 </%self:impl_trait>
 
 <%self:impl_trait style_struct_name="Text" skip_longhands="initial-letter">

components/style/properties/longhands/inherited_text.mako.rs

@@ -141,11 +141,12 @@ ${helpers.predefined_type(
     % endif
 </%helpers:single_keyword>
 
-${helpers.single_keyword(
+${helpers.predefined_type(
     "text-align-last",
-    "auto start end left right center justify",
+    "TextAlignLast",
+    "computed::text::TextAlignLast::Auto",
+    needs_context=False,
     engines="gecko",
-    gecko_constant_prefix="NS_STYLE_TEXT_ALIGN",
     animation_value_type="discrete",
     spec="https://drafts.csswg.org/css-text/#propdef-text-align-last",
 )}

components/style/values/computed/mod.rs

@@ -78,7 +78,7 @@ pub use self::svg::{SVGPaintOrder, SVGStrokeDashArray, SVGWidth};
 pub use self::text::TextUnderlinePosition;
 pub use self::text::{InitialLetter, LetterSpacing, LineBreak, LineHeight};
 pub use self::text::{OverflowWrap, TextOverflow, WordBreak, WordSpacing};
-pub use self::text::{TextAlign, TextEmphasisPosition, TextEmphasisStyle};
+pub use self::text::{TextAlign, TextAlignLast, TextEmphasisPosition, TextEmphasisStyle};
 pub use self::text::{TextDecorationLength, TextDecorationSkipInk};
 pub use self::time::Time;
 pub use self::transform::{Rotate, Scale, Transform, TransformOperation};

components/style/values/computed/text.rs

@@ -18,8 +18,7 @@ use crate::Zero;
 use std::fmt::{self, Write};
 use style_traits::{CssWriter, ToCss};
 
-pub use crate::values::specified::TextAlignKeyword as TextAlign;
+pub use crate::values::specified::text::{TextAlignLast, TextUnderlinePosition};
-pub use crate::values::specified::TextUnderlinePosition;
 pub use crate::values::specified::{LineBreak, OverflowWrap, WordBreak};
 pub use crate::values::specified::{TextDecorationLine, TextEmphasisPosition};
 pub use crate::values::specified::{TextDecorationSkipInk, TextTransform};
@@ -30,6 +29,9 @@ pub type InitialLetter = GenericInitialLetter<CSSFloat, CSSInteger>;
 /// Implements type for `text-decoration-thickness` property.
 pub type TextDecorationLength = GenericTextDecorationLength<LengthPercentage>;
 
+/// The computed value of `text-align`.
+pub type TextAlign = specified::TextAlignKeyword;
+
 /// A computed value for the `letter-spacing` property.
 #[repr(transparent)]
 #[derive(

components/style/values/specified/mod.rs

@@ -85,6 +85,7 @@ pub use self::text::{InitialLetter, LetterSpacing, LineBreak, LineHeight, TextAl
 pub use self::text::{OverflowWrap, TextEmphasisPosition, TextEmphasisStyle, WordBreak};
 pub use self::text::{TextAlignKeyword, TextDecorationLine, TextOverflow, WordSpacing};
 pub use self::text::{TextDecorationLength, TextDecorationSkipInk, TextTransform};
+pub use self::text::TextAlignLast;
 pub use self::time::Time;
 pub use self::transform::{Rotate, Scale, Transform};
 pub use self::transform::{TransformOrigin, TransformStyle, Translate};

components/style/values/specified/text.rs

@@ -517,6 +517,35 @@ impl ToCss for TextTransformOther {
     }
 }
 
+/// Specified and computed value of text-align-last.
+#[derive(
+    Clone,
+    Copy,
+    Debug,
+    Eq,
+    FromPrimitive,
+    Hash,
+    MallocSizeOf,
+    Parse,
+    PartialEq,
+    SpecifiedValueInfo,
+    ToComputedValue,
+    ToCss,
+    ToResolvedValue,
+    ToShmem,
+)]
+#[allow(missing_docs)]
+#[repr(u8)]
+pub enum TextAlignLast {
+    Auto,
+    Start,
+    End,
+    Left,
+    Right,
+    Center,
+    Justify,
+}
+
 /// Specified value of text-align keyword value.
 #[derive(
     Clone,
@@ -535,14 +564,18 @@ impl ToCss for TextTransformOther {
     ToShmem,
 )]
 #[allow(missing_docs)]
+#[repr(u8)]
 pub enum TextAlignKeyword {
     Start,
-    End,
     Left,
     Right,
     Center,
     #[cfg(any(feature = "gecko", feature = "servo-layout-2013"))]
     Justify,
+    #[css(skip)]
+    #[cfg(feature = "gecko")]
+    Char,
+    End,
     #[cfg(feature = "gecko")]
     MozCenter,
     #[cfg(feature = "gecko")]
@@ -555,9 +588,6 @@ pub enum TextAlignKeyword {
     ServoLeft,
     #[cfg(feature = "servo-layout-2013")]
     ServoRight,
-    #[css(skip)]
-    #[cfg(feature = "gecko")]
-    Char,
 }
 
 /// Specified value of text-align property.
@@ -579,14 +609,6 @@ pub enum TextAlign {
     MozCenterOrInherit,
 }
 
-impl TextAlign {
-    /// Convert an enumerated value coming from Gecko to a `TextAlign`.
-    #[cfg(feature = "gecko")]
-    pub fn from_gecko_keyword(kw: u32) -> Self {
-        TextAlign::Keyword(TextAlignKeyword::from_gecko_keyword(kw))
-    }
-}
-
 impl ToComputedValue for TextAlign {
     type ComputedValue = TextAlignKeyword;