Auto merge of #14000 - Wafflespeanut:grid, r=Manishearth

Stylo: Basic support for grid-{row,column}-{start,end}

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- [x] `./mach build-geckolib` does not report any errors
- [x] `./mach test-tidy` does not report any errors

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- [ ] There are tests for these changes

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6 files changed, 142 insertions, 5 deletions

diff --git a/components/style/properties/gecko.mako.rs b/components/style/properties/gecko.mako.rs
index 1fb133f92fd..0c9212e2a11 100644
--- a/components/style/properties/gecko.mako.rs
+++ b/components/style/properties/gecko.mako.rs
@@ -5,7 +5,7 @@
 // `data` comes from components/style/properties.mako.rs; see build.rs for more details.
 
 <%!
-    from data import to_rust_ident
+    from data import to_rust_ident, to_camel_case
     from data import Keyword
 %>
 <%namespace name="helpers" file="/helpers.mako.rs" />
@@ -631,8 +631,15 @@ class Corner(object):
         self.x_index = 2 * index
         self.y_index = 2 * index + 1
 
+class GridLine(object):
+    def __init__(self, name):
+        self.ident = "grid-" + name.lower()
+        self.name = self.ident.replace('-', '_')
+        self.gecko = "m" + to_camel_case(self.ident)
+
 SIDES = [Side("Top", 0), Side("Right", 1), Side("Bottom", 2), Side("Left", 3)]
 CORNERS = [Corner("TOP_LEFT", 0), Corner("TOP_RIGHT", 1), Corner("BOTTOM_RIGHT", 2), Corner("BOTTOM_LEFT", 3)]
+GRID_LINES = map(GridLine, ["row-start", "row-end", "column-start", "column-end"])
 %>
 
 #[allow(dead_code)]
@@ -822,7 +829,7 @@ fn static_assert() {
     % endfor
 </%self:impl_trait>
 
-<% skip_position_longhands = " ".join(x.ident for x in SIDES) %>
+<% skip_position_longhands = " ".join(x.ident for x in SIDES + GRID_LINES) %>
 <%self:impl_trait style_struct_name="Position"
                   skip_longhands="${skip_position_longhands} z-index box-sizing order">
 
@@ -884,6 +891,27 @@ fn static_assert() {
 
     ${impl_simple_copy('order', 'mOrder')}
 
+    % for value in GRID_LINES:
+    pub fn set_${value.name}(&mut self, v: longhands::${value.name}::computed_value::T) {
+        use nsstring::nsCString;
+        use gecko_bindings::structs::{nsStyleGridLine_kMinLine, nsStyleGridLine_kMaxLine};
+
+        let ident = v.ident.unwrap_or(String::new());
+        self.gecko.${value.gecko}.mLineName.assign_utf8(&nsCString::from(&*ident));
+        self.gecko.${value.gecko}.mHasSpan = v.is_span;
+        self.gecko.${value.gecko}.mInteger = v.integer.map(|i| {
+            // clamping the integer between a range
+            cmp::max(nsStyleGridLine_kMinLine, cmp::min(i, nsStyleGridLine_kMaxLine))
+        }).unwrap_or(0);
+    }
+
+    pub fn copy_${value.name}_from(&mut self, other: &Self) {
+        self.gecko.${value.gecko}.mHasSpan = other.gecko.${value.gecko}.mHasSpan;
+        self.gecko.${value.gecko}.mInteger = other.gecko.${value.gecko}.mInteger;
+        self.gecko.${value.gecko}.mLineName.assign(&other.gecko.${value.gecko}.mLineName);
+    }
+    % endfor
+
 </%self:impl_trait>
 
 <% skip_outline_longhands = " ".join("outline-style outline-width".split() +
diff --git a/components/style/properties/longhand/box.mako.rs b/components/style/properties/longhand/box.mako.rs
index 818ed9316e1..dd51bb5b3d3 100644
--- a/components/style/properties/longhand/box.mako.rs
+++ b/components/style/properties/longhand/box.mako.rs
@@ -18,8 +18,7 @@
         values = """inline block inline-block
             table inline-table table-row-group table-header-group table-footer-group
             table-row table-column-group table-column table-cell table-caption
-            list-item flex
-            none
+            list-item flex none
         """.split()
         if product == "gecko":
             values += """inline-flex grid inline-grid ruby ruby-base ruby-base-container
diff --git a/components/style/properties/longhand/position.mako.rs b/components/style/properties/longhand/position.mako.rs
index 529dce1e9d0..f025e658c5b 100644
--- a/components/style/properties/longhand/position.mako.rs
+++ b/components/style/properties/longhand/position.mako.rs
@@ -2,6 +2,7 @@
  * License, v. 2.0. If a copy of the MPL was not distributed with this
  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
 
+<%! from data import to_rust_ident %>
 <%namespace name="helpers" file="/helpers.mako.rs" />
 <% from data import ALL_SIZES, PHYSICAL_SIDES, LOGICAL_SIDES %>
 
@@ -180,3 +181,14 @@ ${helpers.single_keyword("box-sizing",
 // https://drafts.csswg.org/css-images-3/
 ${helpers.single_keyword("object-fit", "fill contain cover none scale-down",
                          products="gecko", animatable=False)}
+
+// https://drafts.csswg.org/css-grid/#propdef-grid-row-start
+<% grid_longhands = ["grid-row-start", "grid-row-end", "grid-column-start", "grid-column-end"] %>
+
+% for longhand in grid_longhands:
+    ${helpers.predefined_type("%s" % longhand,
+                              "GridLine",
+                              "Default::default()",
+                              animatable=False,
+                              products="gecko")}
+% endfor
diff --git a/components/style/values/computed/mod.rs b/components/style/values/computed/mod.rs
index 6d77bf74c80..8a31d59ce10 100644
--- a/components/style/values/computed/mod.rs
+++ b/components/style/values/computed/mod.rs
@@ -14,7 +14,7 @@ pub use cssparser::Color as CSSColor;
 pub use self::image::{EndingShape as GradientShape, Gradient, GradientKind, Image};
 pub use self::image::{LengthOrKeyword, LengthOrPercentageOrKeyword};
 pub use super::{Either, None_};
-pub use super::specified::{Angle, BorderStyle, Time, UrlOrNone};
+pub use super::specified::{Angle, BorderStyle, GridLine, Time, UrlOrNone};
 pub use super::specified::url::UrlExtraData;
 pub use self::length::{CalcLengthOrPercentage, Length, LengthOrNumber, LengthOrPercentage, LengthOrPercentageOrAuto};
 pub use self::length::{LengthOrPercentageOrAutoOrContent, LengthOrPercentageOrNone, LengthOrNone};
diff --git a/components/style/values/specified/grid.rs b/components/style/values/specified/grid.rs
new file mode 100644
index 00000000000..8e6eca56372
--- /dev/null
+++ b/components/style/values/specified/grid.rs
@@ -0,0 +1,96 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+use cssparser::Parser;
+use parser::{Parse, ParserContext};
+use std::fmt;
+use style_traits::ToCss;
+use values::NoViewportPercentage;
+use values::computed::ComputedValueAsSpecified;
+
+// https://drafts.csswg.org/css-grid/#typedef-grid-row-start-grid-line
+#[derive(PartialEq, Clone, Debug)]
+#[cfg_attr(feature = "servo", derive(HeapSizeOf))]
+pub struct GridLine {
+    pub is_span: bool,
+    pub ident: Option<String>,
+    pub integer: Option<i32>,
+}
+
+impl Default for GridLine {
+    fn default() -> Self {
+        GridLine {
+            is_span: false,
+            ident: None,
+            integer: None,
+        }
+    }
+}
+
+impl ToCss for GridLine {
+    fn to_css<W>(&self, dest: &mut W) -> fmt::Result where W: fmt::Write {
+        if !self.is_span && self.ident.is_none() && self.integer.is_none() {
+            return dest.write_str("auto")
+        }
+
+        if self.is_span {
+            try!(dest.write_str("span"));
+        }
+
+        if let Some(i) = self.integer {
+            try!(write!(dest, " {}", i));
+        }
+
+        if let Some(ref s) = self.ident {
+            try!(write!(dest, " {}", s));
+        }
+
+        Ok(())
+    }
+}
+
+impl Parse for GridLine {
+    fn parse(_context: &ParserContext, input: &mut Parser) -> Result<Self, ()> {
+        let mut grid_line = Default::default();
+        if input.try(|i| i.expect_ident_matching("auto")).is_ok() {
+            return Ok(grid_line)
+        }
+
+        for _ in 0..3 {     // Maximum possible entities for <grid-line>
+            if input.try(|i| i.expect_ident_matching("span")).is_ok() {
+                if grid_line.is_span {
+                    return Err(())
+                }
+                grid_line.is_span = true;
+            } else if let Ok(i) = input.try(|i| i.expect_integer()) {
+                if i == 0 || grid_line.integer.is_some() {
+                    return Err(())
+                }
+                grid_line.integer = Some(i);
+            } else if let Ok(name) = input.try(|i| i.expect_ident()) {
+                if grid_line.ident.is_some() {
+                    return Err(())
+                }
+                grid_line.ident = Some(name.into_owned());
+            } else {
+                break
+            }
+        }
+
+        if grid_line.is_span {
+            if let Some(i) = grid_line.integer {
+                if i < 0 {      // disallow negative integers for grid spans
+                    return Err(())
+                }
+            } else {
+                grid_line.integer = Some(1);
+            }
+        }
+
+        Ok(grid_line)
+    }
+}
+
+impl ComputedValueAsSpecified for GridLine {}
+impl NoViewportPercentage for GridLine {}
diff --git a/components/style/values/specified/mod.rs b/components/style/values/specified/mod.rs
index 68caac3f7c4..3b0dd2011b3 100644
--- a/components/style/values/specified/mod.rs
+++ b/components/style/values/specified/mod.rs
@@ -16,6 +16,7 @@ use super::{CSSFloat, HasViewportPercentage, NoViewportPercentage, Either, None_
 use super::computed::{ComputedValueAsSpecified, Context, ToComputedValue};
 use super::computed::Shadow as ComputedShadow;
 
+pub use self::grid::GridLine;
 pub use self::image::{AngleOrCorner, ColorStop, EndingShape as GradientEndingShape, Gradient};
 pub use self::image::{GradientKind, HorizontalDirection, Image, LengthOrKeyword, LengthOrPercentageOrKeyword};
 pub use self::image::{SizeKeyword, VerticalDirection};
@@ -24,6 +25,7 @@ pub use self::length::{Percentage, LengthOrNone, LengthOrNumber, LengthOrPercent
 pub use self::length::{LengthOrPercentageOrNone, LengthOrPercentageOrAutoOrContent, CalcUnit};
 
 pub mod basic_shape;
+pub mod grid;
 pub mod image;
 pub mod length;
 pub mod position;