Background serialization of multiple values.

Similar to animation, the serialization of multiple backgrounds should return the longhands serialization if there are an unequal number of values for the required properties.
servo · Feb 25, 2017 · 3a812b0 · 3a812b0
1 parent b77140a
commit 3a812b0
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Showing 2 changed files with 121 additions and 266 deletions.
diff --git a/components/style/properties/shorthand/background.mako.rs b/components/style/properties/shorthand/background.mako.rs
@@ -13,6 +13,8 @@
     use properties::longhands::{background_color, background_position_x, background_position_y, background_repeat};
     use properties::longhands::{background_attachment, background_image, background_size, background_origin};
     use properties::longhands::background_clip;
+    use properties::longhands::background_clip::single_value::computed_value::T as Clip;
+    use properties::longhands::background_origin::single_value::computed_value::T as Origin;
     use values::specified::position::Position;
     use parser::Parse;
 
@@ -134,27 +136,32 @@
                     _ => None,
                 }
             }
-            use std::cmp;
-            let mut len = 0;
-            % for name in "image position_x position_y repeat size attachment origin clip".split():
-                len = cmp::max(len, extract_value(self.background_${name}).map(|i| i.0.len())
-                                                                          .unwrap_or(0));
-            % endfor
 
+            let len = extract_value(self.background_image).map(|i| i.0.len()).unwrap_or(0);
             // There should be at least one declared value
             if len == 0 {
                 return dest.write_str("")
             }
 
+            // If a value list length is differs then we don't do a shorthand serialization.
+            // The exceptions to this is color which appears once only and is serialized
+            // with the last item.
+            % for name in "image position_x position_y size repeat origin clip attachment".split():
+                if len != extract_value(self.background_${name}).map(|i| i.0.len()).unwrap_or(0) {
+                    return dest.write_str("")
+                }
+            % endfor
+
             let mut first = true;
             for i in 0..len {
                 % for name in "image position_x position_y repeat size attachment origin clip".split():
                     let ${name} = if let DeclaredValue::Value(ref arr) = *self.background_${name} {
-                        arr.0.get(i % arr.0.len())
+                        &arr.0[i]
                     } else {
-                        None
+                        unreachable!()
                     };
                 % endfor
+
                 let color = if i == len - 1 {
                     Some(self.background_color)
                 } else {
@@ -178,75 +185,33 @@
                     None => ()
                 };
 
+                % for name in "image repeat attachment position_x position_y".split():
+                    try!(${name}.to_css(dest));
+                    try!(write!(dest, " "));
+                % endfor
 
-                if let Some(image) = image {
-                    try!(image.to_css(dest));
-                } else {
-                    try!(write!(dest, "none"));
-                }
-
-                try!(write!(dest, " "));
-
-                if let Some(repeat) = repeat {
-                    try!(repeat.to_css(dest));
-                } else {
-                    try!(write!(dest, "repeat"));
-                }
-
-                try!(write!(dest, " "));
-
-                if let Some(attachment) = attachment {
-                    try!(attachment.to_css(dest));
-                } else {
-                    try!(write!(dest, "scroll"));
-                }
-
-                try!(write!(dest, " "));
-
-                try!(position_x.unwrap_or(&background_position_x::single_value
-                                                                ::get_initial_position_value())
-                             .to_css(dest));
-
+                try!(write!(dest, "/ "));
+                try!(size.to_css(dest));
                 try!(write!(dest, " "));
 
-                try!(position_y.unwrap_or(&background_position_y::single_value
-                                                                ::get_initial_position_value())
-                             .to_css(dest));
-
-                if let Some(size) = size {
-                    try!(write!(dest, " / "));
-                    try!(size.to_css(dest));
-                }
-
                 match (origin, clip) {
-                    (Some(origin), Some(clip)) => {
-                        use properties::longhands::background_origin::single_value::computed_value::T as Origin;
-                        use properties::longhands::background_clip::single_value::computed_value::T as Clip;
-
-                        try!(write!(dest, " "));
-
-                        match (origin, clip) {
-                            (&Origin::padding_box, &Clip::padding_box) => {
-                                try!(origin.to_css(dest));
-                            },
-                            (&Origin::border_box, &Clip::border_box) => {
-                                try!(origin.to_css(dest));
-                            },
-                            (&Origin::content_box, &Clip::content_box) => {
-                                try!(origin.to_css(dest));
-                            },
-                            _ => {
-                                try!(origin.to_css(dest));
-                                try!(write!(dest, " "));
-                                try!(clip.to_css(dest));
-                            }
-                        }
+                    (&Origin::padding_box, &Clip::padding_box) => {
+                        try!(origin.to_css(dest));
                     },
-                    _ => {}
+                    (&Origin::border_box, &Clip::border_box) => {
+                        try!(origin.to_css(dest));
+                    },
+                    (&Origin::content_box, &Clip::content_box) => {
+                        try!(origin.to_css(dest));
+                    },
+                    _ => {
+                        try!(origin.to_css(dest));
+                        try!(write!(dest, " "));
+                        try!(clip.to_css(dest));
+                    }
                 };
             }
 
-
             Ok(())
         }
     }