Auto merge of #12895 - emilio:stylo-pseudos, r=bholley

stylo: Improve pseudo element restyling and support the content property.

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

---
<!-- Thank you for contributing to Servo! Please replace each `[ ]` by `[X]` when the step is complete, and replace `__` with appropriate data: -->
- [x] `./mach build -d` does not report any errors
- [x] `./mach test-tidy` does not report any errors

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- [x] These changes do not require tests because geckolib.

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components/style/gecko_selector_impl.rs

@@ -34,7 +34,7 @@ pub struct PseudoElement(Atom, bool);
 
 impl PseudoElement {
     #[inline]
-    fn as_atom(&self) -> &Atom {
+    pub fn as_atom(&self) -> &Atom {
         &self.0
     }
 

components/style/properties/gecko.mako.rs

@@ -455,7 +455,7 @@ impl Clone for ${style_struct.gecko_struct_name} {
 impl Debug for ${style_struct.gecko_struct_name} {
     // FIXME(bholley): Generate this.
     fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
-        write!(f, "GECKO STYLE STRUCT")
+        write!(f, "Gecko style struct: ${style_struct.gecko_struct_name}")
     }
 }
 %else:
@@ -1355,6 +1355,93 @@ fn static_assert() {
     ${impl_coord_copy('column_width', 'mColumnWidth')}
 </%self:impl_trait>
 
+<%self:impl_trait style_struct_name="Counters"
+                  skip_longhands="content">
+    pub fn set_content(&mut self, v: longhands::content::computed_value::T) {
+        use properties::longhands::content::computed_value::T;
+        use properties::longhands::content::computed_value::ContentItem;
+        use gecko_bindings::structs::nsStyleContentData;
+        use gecko_bindings::structs::nsStyleContentType::*;
+        use gecko_bindings::bindings::Gecko_ClearStyleContents;
+
+        // Converts a string as utf16, and returns an owned, zero-terminated raw buffer.
+        fn as_utf16_and_forget(s: &str) -> *mut u16 {
+            use std::mem;
+            let mut vec = s.encode_utf16().collect::<Vec<_>>();
+            vec.push(0u16);
+            let ptr = vec.as_mut_ptr();
+            mem::forget(vec);
+            ptr
+        }
+
+        #[inline(always)]
+        #[cfg(debug_assertions)]
+        fn set_image_tracked(contents: &mut nsStyleContentData, val: bool) {
+            contents.mImageTracked = val;
+        }
+
+        #[inline(always)]
+        #[cfg(not(debug_assertions))]
+        fn set_image_tracked(_contents: &mut nsStyleContentData, _val: bool) {}
+
+        // Ensure destructors run, otherwise we could leak.
+        if !self.gecko.mContents.is_empty() {
+            unsafe {
+                Gecko_ClearStyleContents(&mut self.gecko);
+            }
+        }
+
+        match v {
+            T::none |
+            T::normal => {}, // Do nothing, already cleared.
+            T::Content(items) => {
+                // NB: set_len also reserves the appropriate space.
+                unsafe { self.gecko.mContents.set_len(items.len() as u32) }
+                for (i, item) in items.into_iter().enumerate() {
+                    // TODO: Servo lacks support for attr(), and URIs,
+                    // We don't support images, but need to remember to
+                    // explicitly initialize mImageTracked in debug builds.
+                    set_image_tracked(&mut self.gecko.mContents[i], false);
+                    // NB: Gecko compares the mString value if type is not image
+                    // or URI independently of whatever gets there. In the quote
+                    // cases, they set it to null, so do the same here.
+                    unsafe {
+                        *self.gecko.mContents[i].mContent.mString.as_mut() = ptr::null_mut();
+                    }
+                    match item {
+                        ContentItem::String(value) => {
+                            self.gecko.mContents[i].mType = eStyleContentType_String;
+                            unsafe {
+                                // NB: we share allocators, so doing this is fine.
+                                *self.gecko.mContents[i].mContent.mString.as_mut() =
+                                    as_utf16_and_forget(&value);
+                            }
+                        }
+                        ContentItem::OpenQuote
+                            => self.gecko.mContents[i].mType = eStyleContentType_OpenQuote,
+                        ContentItem::CloseQuote
+                            => self.gecko.mContents[i].mType = eStyleContentType_CloseQuote,
+                        ContentItem::NoOpenQuote
+                            => self.gecko.mContents[i].mType = eStyleContentType_NoOpenQuote,
+                        ContentItem::NoCloseQuote
+                            => self.gecko.mContents[i].mType = eStyleContentType_NoCloseQuote,
+                        ContentItem::Counter(..) |
+                        ContentItem::Counters(..)
+                            => self.gecko.mContents[i].mType = eStyleContentType_Uninitialized,
+                    }
+                }
+            }
+        }
+    }
+
+    pub fn copy_content_from(&mut self, other: &Self) {
+        use gecko_bindings::bindings::Gecko_CopyStyleContentsFrom;
+        unsafe {
+            Gecko_CopyStyleContentsFrom(&mut self.gecko, &other.gecko)
+        }
+    }
+</%self:impl_trait>
+
 <%def name="define_ffi_struct_accessor(style_struct)">
 #[no_mangle]
 #[allow(non_snake_case, unused_variables)]

ports/geckolib/binding_tools/regen.py

@@ -106,8 +106,6 @@ COMPILATION_TARGETS = {
             "Maybe",  # <- AlignedStorage, which means templated union, which
                       # means impossible to represent in stable rust as of
                       # right now.
-            # Union handling falls over for templated types.
-            "StyleShapeSource", "StyleClipPath", "StyleShapeOutside",
         ],
     },
     # Generation of the ffi bindings.
@@ -212,7 +210,7 @@ def extend_object(obj, other):
             obj[key] = copy.deepcopy(other[key])
 
 
-def build(objdir, target_name, kind_name=None,
+def build(objdir, target_name, debug, debugger, kind_name=None,
           output_filename=None, bindgen=None, skip_test=False,
           verbose=False):
     assert target_name in COMPILATION_TARGETS
@@ -346,10 +344,15 @@ def build(objdir, target_name, kind_name=None,
     flags.append(current_target["files"][0].format(objdir))
 
     flags = bindgen + flags
-    output = None
+
+    output = ""
     try:
-        output = subprocess.check_output(flags, stderr=subprocess.STDOUT)
+        if debug:
-        output = output.decode('utf8')
+            flags = [debugger, "--args"] + flags
+            subprocess.check_call(flags)
+        else:
+            output = subprocess.check_output(flags, stderr=subprocess.STDOUT)
+            output = output.decode('utf8')
     except subprocess.CalledProcessError as e:
         print("FAIL\n", e.output.decode('utf8'))
         return 1
@@ -428,7 +431,7 @@ def builds_for(target_name, kind):
 
 def main():
     parser = argparse.ArgumentParser(description=DESCRIPTION)
-    parser.add_argument('--target', default="all",
+    parser.add_argument('--target', default='all',
                         help='The target to build, either "structs" or "bindings"')
     parser.add_argument('--kind',
                         help='Kind of build')
@@ -442,6 +445,11 @@ def main():
     parser.add_argument('--verbose', '-v',
                         action='store_true',
                         help='Be... verbose')
+    parser.add_argument('--debug',
+                        action='store_true',
+                        help='Try to use a debugger to debug bindgen commands (default: gdb)')
+    parser.add_argument('--debugger', default='gdb',
+                        help='Debugger to use. Only used if --debug is passed.')
     parser.add_argument('objdir')
 
     args = parser.parse_args()
@@ -467,7 +475,8 @@ def main():
         return 1
 
     for target, kind in builds_for(args.target, args.kind):
-        ret = build(args.objdir, target, kind,
+        ret = build(args.objdir, target, kind_name=kind,
+                    debug=args.debug, debugger=args.debugger,
                     bindgen=args.bindgen, skip_test=args.skip_test,
                     output_filename=args.output,
                     verbose=args.verbose)

ports/geckolib/gecko_bindings/bindings.rs

@@ -302,7 +302,8 @@ extern "C" {
     pub fn Gecko_GetNodeFlags(node: *mut RawGeckoNode) -> u32;
     pub fn Gecko_SetNodeFlags(node: *mut RawGeckoNode, flags: u32);
     pub fn Gecko_UnsetNodeFlags(node: *mut RawGeckoNode, flags: u32);
-    pub fn Gecko_GetStyleContext(node: *mut RawGeckoNode)
+    pub fn Gecko_GetStyleContext(node: *mut RawGeckoNode,
+                                 aPseudoTagOrNull: *mut nsIAtom)
      -> *mut nsStyleContext;
     pub fn Gecko_CalcStyleDifference(oldstyle: *mut nsStyleContext,
                                      newstyle: ServoComputedValuesBorrowed)
@@ -311,6 +312,11 @@ extern "C" {
                                       change: nsChangeHint);
     pub fn Gecko_EnsureTArrayCapacity(array: *mut ::std::os::raw::c_void,
                                       capacity: usize, elem_size: usize);
+    pub fn Gecko_ClearPODTArray(array: *mut ::std::os::raw::c_void,
+                                elem_size: usize, elem_align: usize);
+    pub fn Gecko_ClearStyleContents(content: *mut nsStyleContent);
+    pub fn Gecko_CopyStyleContentsFrom(content: *mut nsStyleContent,
+                                       other: *const nsStyleContent);
     pub fn Gecko_EnsureImageLayersLength(layers: *mut nsStyleImageLayers,
                                          len: usize);
     pub fn Gecko_InitializeImageLayer(layer: *mut Layer,

ports/geckolib/gecko_bindings/structs_debug.rs

@@ -6389,25 +6389,33 @@ fn bindgen_test_layout_StyleBasicShape() {
     assert_eq!(::std::mem::align_of::<StyleBasicShape>() , 8usize);
 }
 #[repr(C)]
-pub struct StyleShapeSource;
+#[derive(Debug)]
-#[repr(C)]
+pub struct StyleShapeSource<ReferenceBox> {
-pub struct StyleClipPath {
+    pub StyleShapeSource_nsStyleStruct_h_unnamed_26: StyleShapeSource_nsStyleStruct_h_unnamed_26<ReferenceBox>,
-    pub _bindgen_opaque_blob: [u64; 2usize],
+    pub mType: StyleShapeSourceType,
-}
+    pub mReferenceBox: ReferenceBox,
-#[test]
-fn bindgen_test_layout_StyleClipPath() {
-    assert_eq!(::std::mem::size_of::<StyleClipPath>() , 16usize);
-    assert_eq!(::std::mem::align_of::<StyleClipPath>() , 8usize);
 }
 #[repr(C)]
-pub struct StyleShapeOutside {
+#[derive(Debug, Copy, Clone)]
-    pub _bindgen_opaque_blob: [u64; 2usize],
+pub struct StyleShapeSource_nsStyleStruct_h_unnamed_26<ReferenceBox> {
+    pub mBasicShape: __BindgenUnionField<*mut StyleBasicShape>,
+    pub mURL: __BindgenUnionField<*mut FragmentOrURL>,
+    pub _bindgen_data_: u64,
+    pub _phantom0: ::std::marker::PhantomData<ReferenceBox>,
 }
-#[test]
+impl <ReferenceBox> StyleShapeSource_nsStyleStruct_h_unnamed_26<ReferenceBox>
-fn bindgen_test_layout_StyleShapeOutside() {
+ {
-    assert_eq!(::std::mem::size_of::<StyleShapeOutside>() , 16usize);
+    pub unsafe fn mBasicShape(&mut self) -> *mut *mut StyleBasicShape {
-    assert_eq!(::std::mem::align_of::<StyleShapeOutside>() , 8usize);
+        let raw: *mut u8 = ::std::mem::transmute(&self._bindgen_data_);
+        ::std::mem::transmute(raw.offset(0))
+    }
+    pub unsafe fn mURL(&mut self) -> *mut *mut FragmentOrURL {
+        let raw: *mut u8 = ::std::mem::transmute(&self._bindgen_data_);
+        ::std::mem::transmute(raw.offset(0))
+    }
 }
+pub type StyleClipPath = StyleShapeSource<StyleClipPathGeometryBox>;
+pub type StyleShapeOutside = StyleShapeSource<StyleShapeOutsideShapeBox>;
 #[repr(C)]
 pub struct nsStyleDisplay {
     pub mBinding: RefPtr<URLValue>,
@@ -6461,7 +6469,7 @@ pub struct nsStyleDisplay {
     pub mAnimationFillModeCount: u32,
     pub mAnimationPlayStateCount: u32,
     pub mAnimationIterationCountCount: u32,
-    pub mShapeOutside: [u64; 2usize],
+    pub mShapeOutside: StyleShapeOutside,
 }
 #[test]
 fn bindgen_test_layout_nsStyleDisplay() {
@@ -6567,16 +6575,13 @@ fn bindgen_test_layout_nsStyleCounterData() {
 #[derive(Debug)]
 pub struct nsStyleContent {
     pub mMarkerOffset: nsStyleCoord,
-    pub mContents: *mut nsStyleContentData,
+    pub mContents: nsTArray<nsStyleContentData>,
-    pub mIncrements: *mut nsStyleCounterData,
+    pub mIncrements: nsTArray<nsStyleCounterData>,
-    pub mResets: *mut nsStyleCounterData,
+    pub mResets: nsTArray<nsStyleCounterData>,
-    pub mContentCount: u32,
-    pub mIncrementCount: u32,
-    pub mResetCount: u32,
 }
 #[test]
 fn bindgen_test_layout_nsStyleContent() {
-    assert_eq!(::std::mem::size_of::<nsStyleContent>() , 56usize);
+    assert_eq!(::std::mem::size_of::<nsStyleContent>() , 40usize);
     assert_eq!(::std::mem::align_of::<nsStyleContent>() , 8usize);
 }
 #[repr(C)]
@@ -6797,7 +6802,7 @@ fn bindgen_test_layout_nsStyleFilter() {
 #[repr(C)]
 pub struct nsStyleSVGReset {
     pub mMask: nsStyleImageLayers,
-    pub mClipPath: [u64; 2usize],
+    pub mClipPath: StyleClipPath,
     pub mStopColor: nscolor,
     pub mFloodColor: nscolor,
     pub mLightingColor: nscolor,

ports/geckolib/gecko_bindings/structs_release.rs

@@ -6367,25 +6367,33 @@ fn bindgen_test_layout_StyleBasicShape() {
     assert_eq!(::std::mem::align_of::<StyleBasicShape>() , 8usize);
 }
 #[repr(C)]
-pub struct StyleShapeSource;
+#[derive(Debug)]
-#[repr(C)]
+pub struct StyleShapeSource<ReferenceBox> {
-pub struct StyleClipPath {
+    pub StyleShapeSource_nsStyleStruct_h_unnamed_26: StyleShapeSource_nsStyleStruct_h_unnamed_26<ReferenceBox>,
-    pub _bindgen_opaque_blob: [u64; 2usize],
+    pub mType: StyleShapeSourceType,
-}
+    pub mReferenceBox: ReferenceBox,
-#[test]
-fn bindgen_test_layout_StyleClipPath() {
-    assert_eq!(::std::mem::size_of::<StyleClipPath>() , 16usize);
-    assert_eq!(::std::mem::align_of::<StyleClipPath>() , 8usize);
 }
 #[repr(C)]
-pub struct StyleShapeOutside {
+#[derive(Debug, Copy, Clone)]
-    pub _bindgen_opaque_blob: [u64; 2usize],
+pub struct StyleShapeSource_nsStyleStruct_h_unnamed_26<ReferenceBox> {
+    pub mBasicShape: __BindgenUnionField<*mut StyleBasicShape>,
+    pub mURL: __BindgenUnionField<*mut FragmentOrURL>,
+    pub _bindgen_data_: u64,
+    pub _phantom0: ::std::marker::PhantomData<ReferenceBox>,
 }
-#[test]
+impl <ReferenceBox> StyleShapeSource_nsStyleStruct_h_unnamed_26<ReferenceBox>
-fn bindgen_test_layout_StyleShapeOutside() {
+ {
-    assert_eq!(::std::mem::size_of::<StyleShapeOutside>() , 16usize);
+    pub unsafe fn mBasicShape(&mut self) -> *mut *mut StyleBasicShape {
-    assert_eq!(::std::mem::align_of::<StyleShapeOutside>() , 8usize);
+        let raw: *mut u8 = ::std::mem::transmute(&self._bindgen_data_);
+        ::std::mem::transmute(raw.offset(0))
+    }
+    pub unsafe fn mURL(&mut self) -> *mut *mut FragmentOrURL {
+        let raw: *mut u8 = ::std::mem::transmute(&self._bindgen_data_);
+        ::std::mem::transmute(raw.offset(0))
+    }
 }
+pub type StyleClipPath = StyleShapeSource<StyleClipPathGeometryBox>;
+pub type StyleShapeOutside = StyleShapeSource<StyleShapeOutsideShapeBox>;
 #[repr(C)]
 pub struct nsStyleDisplay {
     pub mBinding: RefPtr<URLValue>,
@@ -6439,7 +6447,7 @@ pub struct nsStyleDisplay {
     pub mAnimationFillModeCount: u32,
     pub mAnimationPlayStateCount: u32,
     pub mAnimationIterationCountCount: u32,
-    pub mShapeOutside: [u64; 2usize],
+    pub mShapeOutside: StyleShapeOutside,
 }
 #[test]
 fn bindgen_test_layout_nsStyleDisplay() {
@@ -6544,16 +6552,13 @@ fn bindgen_test_layout_nsStyleCounterData() {
 #[derive(Debug)]
 pub struct nsStyleContent {
     pub mMarkerOffset: nsStyleCoord,
-    pub mContents: *mut nsStyleContentData,
+    pub mContents: nsTArray<nsStyleContentData>,
-    pub mIncrements: *mut nsStyleCounterData,
+    pub mIncrements: nsTArray<nsStyleCounterData>,
-    pub mResets: *mut nsStyleCounterData,
+    pub mResets: nsTArray<nsStyleCounterData>,
-    pub mContentCount: u32,
-    pub mIncrementCount: u32,
-    pub mResetCount: u32,
 }
 #[test]
 fn bindgen_test_layout_nsStyleContent() {
-    assert_eq!(::std::mem::size_of::<nsStyleContent>() , 56usize);
+    assert_eq!(::std::mem::size_of::<nsStyleContent>() , 40usize);
     assert_eq!(::std::mem::align_of::<nsStyleContent>() , 8usize);
 }
 #[repr(C)]
@@ -6774,7 +6779,7 @@ fn bindgen_test_layout_nsStyleFilter() {
 #[repr(C)]
 pub struct nsStyleSVGReset {
     pub mMask: nsStyleImageLayers,
-    pub mClipPath: [u64; 2usize],
+    pub mClipPath: StyleClipPath,
     pub mStopColor: nscolor,
     pub mFloodColor: nscolor,
     pub mLightingColor: nscolor,

ports/geckolib/gecko_bindings/sugar/ns_t_array.rs

@@ -2,7 +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/. */
 
-use bindings::Gecko_EnsureTArrayCapacity;
+use bindings;
 use std::mem;
 use std::ops::{Deref, DerefMut};
 use std::os::raw::c_void;
@@ -38,6 +38,7 @@ impl<T> nsTArray<T> {
     // unsafe, since header may be in shared static or something
     unsafe fn header_mut<'a>(&'a mut self) -> &'a mut nsTArrayHeader {
         debug_assert!(!self.mBuffer.is_null());
+
         mem::transmute(self.mBuffer)
     }
 
@@ -47,12 +48,37 @@ impl<T> nsTArray<T> {
         (self.mBuffer as *const nsTArrayHeader).offset(1) as *mut _
     }
 
-    fn ensure_capacity(&mut self, cap: usize) {
+    /// Ensures the array has enough capacity at least to hold `cap` elements.
-        unsafe {
+    ///
-            Gecko_EnsureTArrayCapacity(self as *mut nsTArray<T> as *mut c_void, cap, mem::size_of::<T>())
+    /// NOTE: This doesn't call the constructor on the values!
+    pub fn ensure_capacity(&mut self, cap: usize) {
+        if cap >= self.len() {
+            unsafe {
+                bindings::Gecko_EnsureTArrayCapacity(self as *mut nsTArray<T> as *mut _,
+                                                     cap, mem::size_of::<T>())
+            }
         }
     }
 
+    /// Clears the array storage without calling the destructor on the values.
+    #[inline]
+    pub unsafe fn clear(&mut self) {
+        if self.len() != 0 {
+            bindings::Gecko_ClearPODTArray(self as *mut nsTArray<T> as *mut _,
+                                           mem::size_of::<T>(),
+                                           mem::align_of::<T>());
+        }
+    }
+
+
+    /// Clears a POD array. This is safe since copy types are memcopyable.
+    #[inline]
+    pub fn clear_pod(&mut self)
+        where T: Copy
+    {
+        unsafe { self.clear() }
+    }
+
     // unsafe because the array may contain uninits
     // This will not call constructors, either manually
     // add bindings or run the typed ensurecapacity call

ports/geckolib/wrapper.rs

@@ -319,15 +319,10 @@ impl<'ln> TNode for GeckoNode<'ln> {
             return None;
         }
 
-        if pseudo.is_some() {
-            // FIXME(emilio): This makes us reconstruct frame for pseudos every
-            // restyle, add a FFI call to get the style context associated with
-            // a PE.
-            return None;
-        }
-
         unsafe {
-            let context_ptr = Gecko_GetStyleContext(self.node);
+            let atom_ptr = pseudo.map(|p| p.as_atom().as_ptr())
+                                 .unwrap_or(ptr::null_mut());
+            let context_ptr = Gecko_GetStyleContext(self.node, atom_ptr);
             context_ptr.as_ref()
         }
     }