Auto merge of #16642 - upsuper:bug1355394, r=heycam

stylo: Implement access to CSSSupportsRule

Servo side change of [bug 1355394](https://bugzilla.mozilla.org/show_bug.cgi?id=1355394).

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components/style/gecko/arc_types.rs

@@ -9,7 +9,7 @@
 #![allow(non_snake_case, missing_docs)]
 
 use gecko_bindings::bindings::{RawServoMediaList, RawServoMediaRule, RawServoNamespaceRule, RawServoPageRule};
-use gecko_bindings::bindings::{RawServoStyleSheet, RawServoImportRule};
+use gecko_bindings::bindings::{RawServoStyleSheet, RawServoImportRule, RawServoSupportsRule};
 use gecko_bindings::bindings::{ServoComputedValues, ServoCssRules};
 use gecko_bindings::structs::{RawServoAnimationValue, RawServoAnimationValueMap};
 use gecko_bindings::structs::{RawServoDeclarationBlock, RawServoStyleRule};
@@ -19,7 +19,8 @@ use parking_lot::RwLock;
 use properties::{ComputedValues, PropertyDeclarationBlock};
 use properties::animated_properties::{AnimationValue, AnimationValueMap};
 use shared_lock::Locked;
-use stylesheets::{CssRules, Stylesheet, StyleRule, ImportRule, MediaRule, NamespaceRule, PageRule};
+use stylesheets::{CssRules, Stylesheet, StyleRule, ImportRule, MediaRule};
+use stylesheets::{NamespaceRule, PageRule, SupportsRule};
 
 macro_rules! impl_arc_ffi {
     ($servo_type:ty => $gecko_type:ty [$addref:ident, $release:ident]) => {
@@ -75,3 +76,6 @@ impl_arc_ffi!(Locked<NamespaceRule> => RawServoNamespaceRule
 
 impl_arc_ffi!(Locked<PageRule> => RawServoPageRule
               [Servo_PageRule_AddRef, Servo_PageRule_Release]);
+
+impl_arc_ffi!(Locked<SupportsRule> => RawServoSupportsRule
+              [Servo_SupportsRule_AddRef, Servo_SupportsRule_Release]);

components/style/gecko_bindings/bindings.rs

@@ -244,6 +244,11 @@ pub type RawServoPageRuleBorrowed<'a> = &'a RawServoPageRule;
 pub type RawServoPageRuleBorrowedOrNull<'a> = Option<&'a RawServoPageRule>;
 enum RawServoPageRuleVoid { }
 pub struct RawServoPageRule(RawServoPageRuleVoid);
+pub type RawServoSupportsRuleStrong = ::gecko_bindings::sugar::ownership::Strong<RawServoSupportsRule>;
+pub type RawServoSupportsRuleBorrowed<'a> = &'a RawServoSupportsRule;
+pub type RawServoSupportsRuleBorrowedOrNull<'a> = Option<&'a RawServoSupportsRule>;
+enum RawServoSupportsRuleVoid { }
+pub struct RawServoSupportsRule(RawServoSupportsRuleVoid);
 pub type RawServoStyleSetOwned = ::gecko_bindings::sugar::ownership::Owned<RawServoStyleSet>;
 pub type RawServoStyleSetOwnedOrNull = ::gecko_bindings::sugar::ownership::OwnedOrNull<RawServoStyleSet>;
 pub type RawServoStyleSetBorrowed<'a> = &'a RawServoStyleSet;
@@ -399,6 +404,12 @@ extern "C" {
 extern "C" {
     pub fn Servo_PageRule_Release(ptr: RawServoPageRuleBorrowed);
 }
+extern "C" {
+    pub fn Servo_SupportsRule_AddRef(ptr: RawServoSupportsRuleBorrowed);
+}
+extern "C" {
+    pub fn Servo_SupportsRule_Release(ptr: RawServoSupportsRuleBorrowed);
+}
 extern "C" {
     pub fn Servo_StyleSet_Drop(ptr: RawServoStyleSetOwned);
 }
@@ -1665,6 +1676,10 @@ extern "C" {
     pub fn Servo_MediaRule_GetCssText(rule: RawServoMediaRuleBorrowed,
                                       result: *mut nsAString);
 }
+extern "C" {
+    pub fn Servo_MediaRule_GetRules(rule: RawServoMediaRuleBorrowed)
+     -> ServoCssRulesStrong;
+}
 extern "C" {
     pub fn Servo_CssRules_GetNamespaceRuleAt(rules: ServoCssRulesBorrowed,
                                              index: u32)
@@ -1690,6 +1705,23 @@ extern "C" {
     pub fn Servo_PageRule_GetCssText(rule: RawServoPageRuleBorrowed,
                                      result: *mut nsAString);
 }
+extern "C" {
+    pub fn Servo_CssRules_GetSupportsRuleAt(rules: ServoCssRulesBorrowed,
+                                            index: u32)
+     -> RawServoSupportsRuleStrong;
+}
+extern "C" {
+    pub fn Servo_SupportsRule_Debug(rule: RawServoSupportsRuleBorrowed,
+                                    result: *mut nsACString);
+}
+extern "C" {
+    pub fn Servo_SupportsRule_GetCssText(rule: RawServoSupportsRuleBorrowed,
+                                         result: *mut nsAString);
+}
+extern "C" {
+    pub fn Servo_SupportsRule_GetRules(rule: RawServoSupportsRuleBorrowed)
+     -> ServoCssRulesStrong;
+}
 extern "C" {
     pub fn Servo_CssRules_GetFontFaceRuleAt(rules: ServoCssRulesBorrowed,
                                             index: u32)
@@ -1712,10 +1744,6 @@ extern "C" {
     pub fn Servo_MediaRule_GetMedia(rule: RawServoMediaRuleBorrowed)
      -> RawServoMediaListStrong;
 }
-extern "C" {
-    pub fn Servo_MediaRule_GetRules(rule: RawServoMediaRuleBorrowed)
-     -> ServoCssRulesStrong;
-}
 extern "C" {
     pub fn Servo_NamespaceRule_GetPrefix(rule: RawServoNamespaceRuleBorrowed)
      -> *mut nsIAtom;
@@ -1733,6 +1761,11 @@ extern "C" {
                                    declarations:
                                        RawServoDeclarationBlockBorrowed);
 }
+extern "C" {
+    pub fn Servo_SupportsRule_GetConditionText(rule:
+                                                   RawServoSupportsRuleBorrowed,
+                                               result: *mut nsAString);
+}
 extern "C" {
     pub fn Servo_ParseProperty(property: nsCSSPropertyID,
                                value: *const nsACString,

ports/geckolib/glue.rs

@@ -36,6 +36,7 @@ use style::gecko_bindings::bindings::{RawServoPageRule, RawServoPageRuleBorrowed
 use style::gecko_bindings::bindings::{RawServoStyleSetBorrowed, RawServoStyleSetOwned};
 use style::gecko_bindings::bindings::{RawServoStyleSheetBorrowed, ServoComputedValuesBorrowed};
 use style::gecko_bindings::bindings::{RawServoStyleSheetStrong, ServoComputedValuesStrong};
+use style::gecko_bindings::bindings::{RawServoSupportsRule, RawServoSupportsRuleBorrowed};
 use style::gecko_bindings::bindings::{ServoCssRulesBorrowed, ServoCssRulesStrong};
 use style::gecko_bindings::bindings::{nsACString, nsAString};
 use style::gecko_bindings::bindings::Gecko_AnimationAppendKeyframe;
@@ -84,7 +85,7 @@ use style::shared_lock::{SharedRwLock, SharedRwLockReadGuard, StylesheetGuards,
 use style::string_cache::Atom;
 use style::stylesheets::{CssRule, CssRules, CssRuleType, CssRulesHelpers};
 use style::stylesheets::{ImportRule, MediaRule, NamespaceRule, Origin};
-use style::stylesheets::{PageRule, Stylesheet, StyleRule};
+use style::stylesheets::{PageRule, Stylesheet, StyleRule, SupportsRule};
 use style::stylesheets::StylesheetLoader as StyleStylesheetLoader;
 use style::supports::parse_condition_or_declaration;
 use style::thread_state;
@@ -780,13 +781,30 @@ macro_rules! impl_basic_rule_funcs {
     }
 }
 
+macro_rules! impl_group_rule_funcs {
+    { ($name:ident, $rule_type:ty, $raw_type:ty),
+      get_rules: $get_rules:ident,
+      $($basic:tt)+
+    } => {
+        impl_basic_rule_funcs! { ($name, $rule_type, $raw_type), $($basic)+ }
+
+        #[no_mangle]
+        pub extern "C" fn $get_rules(rule: &$raw_type) -> ServoCssRulesStrong {
+            read_locked_arc(rule, |rule: &$rule_type| {
+                rule.rules.clone().into_strong()
+            })
+        }
+    }
+}
+
 impl_basic_rule_funcs! { (Style, StyleRule, RawServoStyleRule),
     getter: Servo_CssRules_GetStyleRuleAt,
     debug: Servo_StyleRule_Debug,
     to_css: Servo_StyleRule_GetCssText,
 }
 
-impl_basic_rule_funcs! { (Media, MediaRule, RawServoMediaRule),
+impl_group_rule_funcs! { (Media, MediaRule, RawServoMediaRule),
+    get_rules: Servo_MediaRule_GetRules,
     getter: Servo_CssRules_GetMediaRuleAt,
     debug: Servo_MediaRule_Debug,
     to_css: Servo_MediaRule_GetCssText,
@@ -804,6 +822,13 @@ impl_basic_rule_funcs! { (Page, PageRule, RawServoPageRule),
     to_css: Servo_PageRule_GetCssText,
 }
 
+impl_group_rule_funcs! { (Supports, SupportsRule, RawServoSupportsRule),
+    get_rules: Servo_SupportsRule_GetRules,
+    getter: Servo_CssRules_GetSupportsRuleAt,
+    debug: Servo_SupportsRule_Debug,
+    to_css: Servo_SupportsRule_GetCssText,
+}
+
 #[no_mangle]
 pub extern "C" fn Servo_CssRules_GetFontFaceRuleAt(rules: ServoCssRulesBorrowed, index: u32)
                                                    -> *mut nsCSSFontFaceRule
@@ -847,13 +872,6 @@ pub extern "C" fn Servo_MediaRule_GetMedia(rule: RawServoMediaRuleBorrowed) -> R
     })
 }
 
-#[no_mangle]
-pub extern "C" fn Servo_MediaRule_GetRules(rule: RawServoMediaRuleBorrowed) -> ServoCssRulesStrong {
-    read_locked_arc(rule, |rule: &MediaRule| {
-        rule.rules.clone().into_strong()
-    })
-}
-
 #[no_mangle]
 pub extern "C" fn Servo_NamespaceRule_GetPrefix(rule: RawServoNamespaceRuleBorrowed) -> *mut nsIAtom {
     read_locked_arc(rule, |rule: &NamespaceRule| {
@@ -882,6 +900,14 @@ pub extern "C" fn Servo_PageRule_SetStyle(rule: RawServoPageRuleBorrowed,
     })
 }
 
+#[no_mangle]
+pub extern "C" fn Servo_SupportsRule_GetConditionText(rule: RawServoSupportsRuleBorrowed,
+                                                      result: *mut nsAString) {
+    read_locked_arc(rule, |rule: &SupportsRule| {
+        rule.condition.to_css(unsafe { result.as_mut().unwrap() }).unwrap();
+    })
+}
+
 #[no_mangle]
 pub extern "C" fn Servo_ComputedValues_GetForAnonymousBox(parent_style_or_null: ServoComputedValuesBorrowedOrNull,
                                                           pseudo_tag: *mut nsIAtom,