Handle position property

Author: devongovett

README.md

@@ -24,34 +24,34 @@ A WIP CSS parser, transformer, and minifier written in Rust.
 
 ```
 $ node bench.js bootstrap-4.css 
-cssnano: 557.216ms
+cssnano: 539.997ms
 159636 bytes
 
-esbuild: 17.79ms
+esbuild: 17.399ms
 160332 bytes
 
-parcel-css: 5.231ms
-144293 bytes
+parcel-css: 4.975ms
+144254 bytes
 
 
 $ node bench.js animate.css
-cssnano: 279.961ms
+cssnano: 283.105ms
 71723 bytes
 
-esbuild: 11.781ms
+esbuild: 11.858ms
 72183 bytes
 
-parcel-css: 2.029ms
+parcel-css: 2.039ms
 23707 bytes
 
 
 $ node bench.js tailwind.css 
-cssnano: 2.193s
+cssnano: 2.200s
 1925626 bytes
 
-esbuild: 106.392ms
+esbuild: 109.223ms
 1961642 bytes
 
-parcel-css: 43.564ms
-1906588 bytes
+parcel-css: 41.589ms
+1906468 bytes
 ```

src/declaration.rs

@@ -15,7 +15,8 @@ use crate::properties::{
   prefix_handler::PrefixHandler,
   display::DisplayHandler,
   transform::TransformHandler,
-  text::TextDecorationHandler
+  text::TextDecorationHandler,
+  position::PositionHandler,
 };
 use crate::properties::prefixes::Browsers;
 
@@ -82,6 +83,7 @@ pub struct DeclarationHandler {
   transition: TransitionHandler,
   animation: AnimationHandler,
   display: DisplayHandler,
+  position: PositionHandler,
   transform: TransformHandler,
   prefix: PrefixHandler,
   decls: DeclarationList
@@ -97,6 +99,7 @@ impl DeclarationHandler{
       transition: TransitionHandler::new(targets),
       animation: AnimationHandler::new(targets),
       display: DisplayHandler::new(targets),
+      position: PositionHandler::new(targets),
       transform: TransformHandler::new(targets),
       text: TextDecorationHandler::new(targets),
       prefix: PrefixHandler::new(targets),
@@ -121,6 +124,7 @@ impl DeclarationHandler{
     self.transition.handle_property(property, &mut self.decls) ||
     self.animation.handle_property(property, &mut self.decls) ||
     self.display.handle_property(property, &mut self.decls) ||
+    self.position.handle_property(property, &mut self.decls) ||
     self.transform.handle_property(property, &mut self.decls) ||
     self.prefix.handle_property(property, &mut self.decls)
   }
@@ -140,6 +144,7 @@ impl DeclarationHandler{
     self.transition.finalize(&mut self.decls);
     self.animation.finalize(&mut self.decls);
     self.display.finalize(&mut self.decls);
+    self.position.finalize(&mut self.decls);
     self.transform.finalize(&mut self.decls);
     self.prefix.finalize(&mut self.decls);
     std::mem::take(&mut self.decls.declarations)

src/lib.rs

@@ -4485,4 +4485,60 @@ mod tests {
     minify_test(".foo { text-shadow: 1px 1px yellow; }", ".foo{text-shadow:1px 1px #ff0}");
     minify_test(".foo { text-shadow: 1px 1px yellow, 2px 3px red; }", ".foo{text-shadow:1px 1px #ff0,2px 3px red}");
   }
+
+  #[test]
+  fn test_position() {
+    test(r#"
+      .foo {
+        position: relative;
+        position: absolute;
+      }
+    "#, indoc! {r#"
+      .foo {
+        position: absolute;
+      }
+    "#});
+
+    test(r#"
+      .foo {
+        position: -webkit-sticky;
+        position: sticky;
+      }
+    "#, indoc! {r#"
+      .foo {
+        position: -webkit-sticky;
+        position: sticky;
+      }
+    "#});
+
+    prefix_test(r#"
+      .foo {
+        position: sticky;
+      }
+    "#, indoc! {r#"
+      .foo {
+        position: -webkit-sticky;
+        position: sticky;
+      }
+    "#},
+    Browsers {
+      safari: Some(8 << 16),
+      ..Browsers::default()
+    });
+
+    prefix_test(r#"
+      .foo {
+        position: -webkit-sticky;
+        position: sticky;
+      }
+    "#, indoc! {r#"
+      .foo {
+        position: sticky;
+      }
+    "#},
+    Browsers {
+      safari: Some(13 << 16),
+      ..Browsers::default()
+    });
+  }
 }

src/properties/mod.rs

@@ -16,6 +16,7 @@ pub mod prefixes;
 pub mod prefix_handler;
 pub mod display;
 pub mod text;
+pub mod position;
 
 use cssparser::*;
 use custom::*;
@@ -222,6 +223,8 @@ define_properties! {
   "max-inline-size": MaxInlineSize(MinMaxSize),
   "box-sizing": BoxSizing(BoxSizing, VendorPrefix) / "webkit" / "moz",
 
+  // https://www.w3.org/TR/2020/WD-css-position-3-20200519
+  "position": Position(position::Position),
   "top": Top(LengthPercentageOrAuto),
   "bottom": Bottom(LengthPercentageOrAuto),
   "left": Left(LengthPercentageOrAuto),

src/properties/position.rs

@@ -0,0 +1,105 @@
+use cssparser::*;
+use crate::traits::{Parse, ToCss, PropertyHandler};
+use super::{Property, VendorPrefix};
+use super::prefixes::{Feature, Browsers};
+use crate::declaration::DeclarationList;
+use crate::printer::Printer;
+
+/// https://www.w3.org/TR/2020/WD-css-position-3-20200519/#position-property
+#[derive(Debug, Clone, PartialEq)]
+pub enum Position {
+  Static,
+  Relative,
+  Absolute,
+  Sticky(VendorPrefix),
+  Fixed
+}
+
+impl Parse for Position {
+  fn parse<'i, 't>(input: &mut Parser<'i, 't>) -> Result<Self, ParseError<'i, ()>> {
+    let location = input.current_source_location();
+    let ident = input.expect_ident()?;
+    match_ignore_ascii_case! { &*ident,
+      "static" => Ok(Position::Static),
+      "relative" => Ok(Position::Relative),
+      "absolute" => Ok(Position::Absolute),
+      "fixed" => Ok(Position::Fixed),
+      "sticky" => Ok(Position::Sticky(VendorPrefix::None)),
+      "-webkit-sticky" => Ok(Position::Sticky(VendorPrefix::WebKit)),
+      _ => Err(location.new_unexpected_token_error(
+        cssparser::Token::Ident(ident.clone())
+      ))
+    }
+  }
+}
+
+impl ToCss for Position {
+  fn to_css<W>(&self, dest: &mut Printer<W>) -> std::fmt::Result where W: std::fmt::Write {
+    match self {
+      Position::Static => dest.write_str("static"),
+      Position::Relative => dest.write_str("relative"),
+      Position::Absolute => dest.write_str("absolute"),
+      Position::Fixed => dest.write_str("fixed"),
+      Position::Sticky(prefix) => {
+        prefix.to_css(dest)?;
+        dest.write_str("sticky")
+      }
+    }
+  }
+}
+
+#[derive(Default)]
+pub struct PositionHandler {
+  targets: Option<Browsers>,
+  position: Option<Position>
+}
+
+impl PositionHandler {
+  pub fn new(targets: Option<Browsers>) -> PositionHandler {
+    PositionHandler {
+      targets,
+      ..PositionHandler::default()
+    }
+  }
+}
+
+impl PropertyHandler for PositionHandler {
+  fn handle_property(&mut self, property: &Property, _: &mut DeclarationList) -> bool {
+    if let Property::Position(position) = property {
+      if let (Some(Position::Sticky(cur)), Position::Sticky(new)) = (&mut self.position, position) {
+        *cur |= *new;
+      } else {
+        self.position = Some(position.clone());
+      }
+
+      return true
+    }
+
+    false
+  }
+
+  fn finalize(&mut self, dest: &mut DeclarationList) {
+    if let Some(position) = std::mem::take(&mut self.position) {
+      match position {
+        Position::Sticky(mut prefix) => {
+          if prefix.contains(VendorPrefix::None) {
+            if let Some(targets) = self.targets {
+              prefix = Feature::Sticky.prefixes_for(targets)
+            }
+          }
+
+          if prefix.contains(VendorPrefix::WebKit) {
+            dest.push(Property::Position(Position::Sticky(VendorPrefix::WebKit)))
+          }
+
+          if prefix.contains(VendorPrefix::None) {
+            dest.push(Property::Position(Position::Sticky(VendorPrefix::None)))
+          }
+        }
+        _ => {
+          dest.push(Property::Position(position))
+        }
+      }
+    }
+  }
+}