Auto merge of #14055 - heycam:cursor, r=Manishearth

support cursor property url() values in stylo

<!-- Please describe your changes on the following line: -->

This is the Servo-side change for [bug 1310560](https://bugzilla.mozilla.org/show_bug.cgi?id=1310560), which @Manishearth has already r+ed.

---
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- [ ] `./mach build -d` does not report any errors
- [X] `./mach test-tidy` does not report any errors
- [ ] These changes fix #__ (github issue number if applicable).

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- [ ] There are tests for these changes OR
- [ ] These changes do not require tests because _____

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7 files changed, 158 insertions, 23 deletions

diff --git a/components/layout/display_list_builder.rs b/components/layout/display_list_builder.rs
index 500af800939..4505ac10192 100644
--- a/components/layout/display_list_builder.rs
+++ b/components/layout/display_list_builder.rs
@@ -2246,8 +2246,8 @@ impl ServoComputedValuesCursorUtility for ServoComputedValues {
     fn get_cursor(&self, default_cursor: Cursor) -> Option<Cursor> {
         match (self.get_pointing().pointer_events, self.get_pointing().cursor) {
             (pointer_events::T::none, _) => None,
-            (pointer_events::T::auto, cursor::T::AutoCursor) => Some(default_cursor),
-            (pointer_events::T::auto, cursor::T::SpecifiedCursor(cursor)) => Some(cursor),
+            (pointer_events::T::auto, cursor::Keyword::AutoCursor) => Some(default_cursor),
+            (pointer_events::T::auto, cursor::Keyword::SpecifiedCursor(cursor)) => Some(cursor),
         }
     }
 }
diff --git a/components/style/binding_tools/regen.py b/components/style/binding_tools/regen.py
index 78a22738f1a..88ed56baf00 100755
--- a/components/style/binding_tools/regen.py
+++ b/components/style/binding_tools/regen.py
@@ -278,6 +278,7 @@ COMPILATION_TARGETS = {
             "nsCSSValue",
             "nsCSSValueSharedList",
             "nsChangeHint",
+            "nsCursorImage",
             "nsFont",
             "nsIAtom",
             "nsIDocument",
diff --git a/components/style/gecko_bindings/bindings.rs b/components/style/gecko_bindings/bindings.rs
index a17d2df57bc..dcd961263c6 100644
--- a/components/style/gecko_bindings/bindings.rs
+++ b/components/style/gecko_bindings/bindings.rs
@@ -60,6 +60,7 @@ use gecko_bindings::structs::nsCSSShadowArray;
 use gecko_bindings::structs::nsCSSValue;
 use gecko_bindings::structs::nsCSSValueSharedList;
 use gecko_bindings::structs::nsChangeHint;
+use gecko_bindings::structs::nsCursorImage;
 use gecko_bindings::structs::nsFont;
 use gecko_bindings::structs::nsIAtom;
 use gecko_bindings::structs::nsIDocument;
@@ -511,6 +512,21 @@ extern "C" {
                                         src: *const nsStyleList);
 }
 extern "C" {
+    pub fn Gecko_SetCursorArrayLength(ui: *mut nsStyleUserInterface,
+                                      len: usize);
+}
+extern "C" {
+    pub fn Gecko_SetCursorImage(cursor: *mut nsCursorImage,
+                                string_bytes: *const u8, string_length: u32,
+                                base_uri: *mut ThreadSafeURIHolder,
+                                referrer: *mut ThreadSafeURIHolder,
+                                principal: *mut ThreadSafePrincipalHolder);
+}
+extern "C" {
+    pub fn Gecko_CopyCursorArrayFrom(dest: *mut nsStyleUserInterface,
+                                     src: *const nsStyleUserInterface);
+}
+extern "C" {
     pub fn Gecko_SetMozBinding(style_struct: *mut nsStyleDisplay,
                                string_bytes: *const u8, string_length: u32,
                                base_uri: *mut ThreadSafeURIHolder,
diff --git a/components/style/gecko_bindings/structs_debug.rs b/components/style/gecko_bindings/structs_debug.rs
index 298f661ac28..eaa06e839e2 100644
--- a/components/style/gecko_bindings/structs_debug.rs
+++ b/components/style/gecko_bindings/structs_debug.rs
@@ -11866,7 +11866,7 @@ pub struct nsCursorImage {
     pub mHaveHotspot: bool,
     pub mHotspotX: f32,
     pub mHotspotY: f32,
-    pub mImage: nsCOMPtr<imgIRequest>,
+    pub mImage: RefPtr<nsStyleImageRequest>,
 }
 #[test]
 fn bindgen_test_layout_nsCursorImage() {
diff --git a/components/style/gecko_bindings/structs_release.rs b/components/style/gecko_bindings/structs_release.rs
index c8e67da2070..9a2686b93f7 100644
--- a/components/style/gecko_bindings/structs_release.rs
+++ b/components/style/gecko_bindings/structs_release.rs
@@ -11822,7 +11822,7 @@ pub struct nsCursorImage {
     pub mHaveHotspot: bool,
     pub mHotspotX: f32,
     pub mHotspotY: f32,
-    pub mImage: nsCOMPtr<imgIRequest>,
+    pub mImage: RefPtr<nsStyleImageRequest>,
 }
 #[test]
 fn bindgen_test_layout_nsCursorImage() {
diff --git a/components/style/properties/gecko.mako.rs b/components/style/properties/gecko.mako.rs
index a82dcd4a4e0..b8d02879368 100644
--- a/components/style/properties/gecko.mako.rs
+++ b/components/style/properties/gecko.mako.rs
@@ -19,6 +19,7 @@ use gecko_bindings::bindings::Gecko_Construct_${style_struct.gecko_ffi_name};
 use gecko_bindings::bindings::Gecko_CopyConstruct_${style_struct.gecko_ffi_name};
 use gecko_bindings::bindings::Gecko_Destroy_${style_struct.gecko_ffi_name};
 % endfor
+use gecko_bindings::bindings::Gecko_CopyCursorArrayFrom;
 use gecko_bindings::bindings::Gecko_CopyFontFamilyFrom;
 use gecko_bindings::bindings::Gecko_CopyImageValueFrom;
 use gecko_bindings::bindings::Gecko_CopyListStyleImageFrom;
@@ -28,6 +29,8 @@ use gecko_bindings::bindings::Gecko_EnsureImageLayersLength;
 use gecko_bindings::bindings::Gecko_FontFamilyList_AppendGeneric;
 use gecko_bindings::bindings::Gecko_FontFamilyList_AppendNamed;
 use gecko_bindings::bindings::Gecko_FontFamilyList_Clear;
+use gecko_bindings::bindings::Gecko_SetCursorArrayLength;
+use gecko_bindings::bindings::Gecko_SetCursorImage;
 use gecko_bindings::bindings::Gecko_SetListStyleImage;
 use gecko_bindings::bindings::Gecko_SetListStyleImageNone;
 use gecko_bindings::bindings::Gecko_SetListStyleType;
@@ -2195,12 +2198,12 @@ clip-path
 <%self:impl_trait style_struct_name="Pointing"
                   skip_longhands="cursor">
     pub fn set_cursor(&mut self, v: longhands::cursor::computed_value::T) {
-        use properties::longhands::cursor::computed_value::T;
+        use properties::longhands::cursor::computed_value::Keyword;
         use style_traits::cursor::Cursor;
 
-        self.gecko.mCursor = match v {
-            T::AutoCursor => structs::NS_STYLE_CURSOR_AUTO,
-            T::SpecifiedCursor(cursor) => match cursor {
+        self.gecko.mCursor = match v.keyword {
+            Keyword::AutoCursor => structs::NS_STYLE_CURSOR_AUTO,
+            Keyword::SpecifiedCursor(cursor) => match cursor {
                 Cursor::None => structs::NS_STYLE_CURSOR_NONE,
                 Cursor::Default => structs::NS_STYLE_CURSOR_DEFAULT,
                 Cursor::Pointer => structs::NS_STYLE_CURSOR_POINTER,
@@ -2238,9 +2241,34 @@ clip-path
                 Cursor::ZoomOut => structs::NS_STYLE_CURSOR_ZOOM_OUT,
             }
         } as u8;
+
+        unsafe {
+            Gecko_SetCursorArrayLength(&mut self.gecko, v.images.len());
+        }
+        for i in 0..v.images.len() {
+            let image = &v.images[i];
+            let extra_data = image.url.extra_data();
+            let (ptr, len) = image.url.as_slice_components();
+            unsafe {
+                Gecko_SetCursorImage(&mut self.gecko.mCursorImages[i],
+                                     ptr, len as u32,
+                                     extra_data.base.get(),
+                                     extra_data.referrer.get(),
+                                     extra_data.principal.get());
+            }
+            // We don't need to record this struct as uncacheable, like when setting
+            // background-image to a url() value, since only properties in reset structs
+            // are re-used from the applicable declaration cache, and the Pointing struct
+            // is an inherited struct.
+        }
     }
 
-    ${impl_simple_copy('cursor', 'mCursor')}
+    pub fn copy_cursor_from(&mut self, other: &Self) {
+        self.gecko.mCursor = other.gecko.mCursor;
+        unsafe {
+            Gecko_CopyCursorArrayFrom(&mut self.gecko, &other.gecko);
+        }
+    }
 </%self:impl_trait>
 
 <%self:impl_trait style_struct_name="Column"
diff --git a/components/style/properties/longhand/pointing.mako.rs b/components/style/properties/longhand/pointing.mako.rs
index f140b32336e..c46e4fdb841 100644
--- a/components/style/properties/longhand/pointing.mako.rs
+++ b/components/style/properties/longhand/pointing.mako.rs
@@ -10,6 +10,7 @@
     pub use self::computed_value::T as SpecifiedValue;
     use values::NoViewportPercentage;
     use values::computed::ComputedValueAsSpecified;
+    use values::specified::url::SpecifiedUrl;
 
     impl ComputedValueAsSpecified for SpecifiedValue {}
     impl NoViewportPercentage for SpecifiedValue {}
@@ -18,38 +19,127 @@
         use std::fmt;
         use style_traits::cursor::Cursor;
         use style_traits::ToCss;
+        use values::specified::url::SpecifiedUrl;
 
-        #[derive(Clone, PartialEq, Eq, Copy, Debug)]
+        #[derive(Clone, PartialEq, Copy, Debug)]
         #[cfg_attr(feature = "servo", derive(HeapSizeOf))]
-        pub enum T {
+        pub enum Keyword {
             AutoCursor,
             SpecifiedCursor(Cursor),
         }
 
-        impl ToCss for T {
+        #[cfg(not(feature = "gecko"))]
+        pub type T = Keyword;
+
+        #[cfg(feature = "gecko")]
+        #[derive(Clone, PartialEq, Debug)]
+        pub struct Image {
+            pub url: SpecifiedUrl,
+            pub hotspot: Option<(f32, f32)>,
+        }
+
+        #[cfg(feature = "gecko")]
+        #[derive(Clone, PartialEq, Debug)]
+        pub struct T {
+            pub images: Vec<Image>,
+            pub keyword: Keyword,
+        }
+
+        impl ToCss for Keyword {
             fn to_css<W>(&self, dest: &mut W) -> fmt::Result where W: fmt::Write {
                 match *self {
-                    T::AutoCursor => dest.write_str("auto"),
-                    T::SpecifiedCursor(c) => c.to_css(dest),
+                    Keyword::AutoCursor => dest.write_str("auto"),
+                    Keyword::SpecifiedCursor(c) => c.to_css(dest),
+                }
+            }
+        }
+
+        #[cfg(feature = "gecko")]
+        impl ToCss for Image {
+            fn to_css<W>(&self, dest: &mut W) -> fmt::Result where W: fmt::Write {
+                try!(self.url.to_css(dest));
+                if let Some((x, y)) = self.hotspot {
+                    try!(dest.write_str(" "));
+                    try!(x.to_css(dest));
+                    try!(dest.write_str(" "));
+                    try!(y.to_css(dest));
+                }
+                Ok(())
+            }
+        }
+
+        #[cfg(feature = "gecko")]
+        impl ToCss for T {
+            fn to_css<W>(&self, dest: &mut W) -> fmt::Result where W: fmt::Write {
+                for url in &self.images {
+                    try!(url.to_css(dest));
+                    try!(dest.write_str(", "));
                 }
+                self.keyword.to_css(dest)
             }
         }
     }
 
+    #[cfg(not(feature = "gecko"))]
     #[inline]
     pub fn get_initial_value() -> computed_value::T {
-        computed_value::T::AutoCursor
+        computed_value::Keyword::AutoCursor
     }
+
+    #[cfg(feature = "gecko")]
+    #[inline]
+    pub fn get_initial_value() -> computed_value::T {
+        computed_value::T {
+            images: vec![],
+            keyword: computed_value::Keyword::AutoCursor
+        }
+    }
+
+    impl Parse for computed_value::Keyword {
+        fn parse(input: &mut Parser) -> Result<computed_value::Keyword, ()> {
+            use std::ascii::AsciiExt;
+            use style_traits::cursor::Cursor;
+            let ident = try!(input.expect_ident());
+            if ident.eq_ignore_ascii_case("auto") {
+                Ok(computed_value::Keyword::AutoCursor)
+            } else {
+                Cursor::from_css_keyword(&ident).map(computed_value::Keyword::SpecifiedCursor)
+            }
+        }
+    }
+
+    #[cfg(feature = "gecko")]
+    fn parse_image(context: &ParserContext, input: &mut Parser) -> Result<computed_value::Image, ()> {
+        Ok(computed_value::Image {
+            url: try!(SpecifiedUrl::parse(context, input)),
+            hotspot: match input.try(|input| input.expect_number()) {
+                Ok(number) => Some((number, try!(input.expect_number()))),
+                Err(()) => None,
+            },
+        })
+    }
+
+    #[cfg(not(feature = "gecko"))]
     pub fn parse(_context: &ParserContext, input: &mut Parser) -> Result<SpecifiedValue, ()> {
-        use std::ascii::AsciiExt;
-        use style_traits::cursor::Cursor;
-        let ident = try!(input.expect_ident());
-        if ident.eq_ignore_ascii_case("auto") {
-            Ok(SpecifiedValue::AutoCursor)
-        } else {
-            Cursor::from_css_keyword(&ident)
-            .map(SpecifiedValue::SpecifiedCursor)
+        computed_value::Keyword::parse(input)
+    }
+
+    /// cursor: [<url> [<number> <number>]?]# [auto | default | ...]
+    #[cfg(feature = "gecko")]
+    pub fn parse(context: &ParserContext, input: &mut Parser) -> Result<SpecifiedValue, ()> {
+        let mut images = vec![];
+        loop {
+            match input.try(|input| parse_image(context, input)) {
+                Ok(image) => images.push(image),
+                Err(()) => break,
+            }
+            try!(input.expect_comma());
         }
+
+        Ok(computed_value::T {
+            images: images,
+            keyword: try!(computed_value::Keyword::parse(input)),
+        })
     }
 </%helpers:longhand>