Bug 1338486: Support implied parentheses in CSS.supports; r=xidorn

MozReview-Commit-ID: CUo371Hvj4T

--HG--
extra : rebase_source : ee80540522e959bdf6d7ec5bd5a45081dbd9a384

layout/style/CSS.cpp

@@ -93,7 +93,8 @@ CSS::Supports(const GlobalObject& aGlobal,
 
   nsCSSParser parser;
   return parser.EvaluateSupportsCondition(aCondition, info.mDocURI,
-                                          info.mBaseURI, info.mPrincipal);
+                                          info.mBaseURI, info.mPrincipal,
+                                          css::SupportsParsingSettings::ImpliedParentheses);
 }
 
 /* static */ void

layout/style/nsCSSParser.cpp

@@ -263,7 +263,9 @@ public:
   bool EvaluateSupportsCondition(const nsAString& aCondition,
                                  nsIURI* aDocURL,
                                  nsIURI* aBaseURL,
-                                 nsIPrincipal* aDocPrincipal);
+                                 nsIPrincipal* aDocPrincipal,
+                                 SupportsParsingSettings aSettings
+                                  = SupportsParsingSettings::Normal);
 
   already_AddRefed<nsIAtom> ParseCounterStyleName(const nsAString& aBuffer,
                                                   nsIURI* aURL);
@@ -2414,7 +2416,8 @@ bool
 CSSParserImpl::EvaluateSupportsCondition(const nsAString& aDeclaration,
                                          nsIURI* aDocURL,
                                          nsIURI* aBaseURL,
-                                         nsIPrincipal* aDocPrincipal)
+                                         nsIPrincipal* aDocPrincipal,
+                                         SupportsParsingSettings aSettings)
 {
   nsCSSScanner scanner(aDeclaration, 0);
   css::ErrorReporter reporter(scanner, mSheet, mChildLoader, aDocURL);
@@ -2422,7 +2425,13 @@ CSSParserImpl::EvaluateSupportsCondition(const nsAString& aDeclaration,
   nsAutoSuppressErrors suppressErrors(this);
 
   bool conditionMet;
-  bool parsedOK = ParseSupportsCondition(conditionMet) && !GetToken(true);
+  bool parsedOK;
+
+  if (aSettings == SupportsParsingSettings::ImpliedParentheses) {
+    parsedOK = ParseSupportsConditionInParensInsideParens(conditionMet) && !GetToken(true);
+  } else {
+    parsedOK = ParseSupportsCondition(conditionMet) && !GetToken(true);
+  }
 
   CLEAR_ERROR();
   ReleaseScanner();
@@ -18155,10 +18164,12 @@ bool
 nsCSSParser::EvaluateSupportsCondition(const nsAString& aCondition,
                                        nsIURI* aDocURL,
                                        nsIURI* aBaseURL,
-                                       nsIPrincipal* aDocPrincipal)
+                                       nsIPrincipal* aDocPrincipal,
+                                       SupportsParsingSettings aSettings)
 {
   return static_cast<CSSParserImpl*>(mImpl)->
-    EvaluateSupportsCondition(aCondition, aDocURL, aBaseURL, aDocPrincipal);
+    EvaluateSupportsCondition(aCondition, aDocURL, aBaseURL,
+                              aDocPrincipal, aSettings);
 }
 
 bool

layout/style/nsCSSParser.h

@@ -34,6 +34,12 @@ namespace css {
 class Rule;
 class Declaration;
 class StyleRule;
+
+enum class SupportsParsingSettings {
+  Normal,
+  ImpliedParentheses
+};
+
 } // namespace css
 } // namespace mozilla
 
@@ -252,11 +258,17 @@ public:
   /**
    * Parse an @supports condition and returns the result of evaluating the
    * condition.
+   *
+   * The one-argument CSS.supports() allows for providing a parentheses-less
+   * @supports condition, i.e. the parentheses are "implied". In such a case,
+   * aSettings can be set to ImpliedParentheses.
    */
   bool EvaluateSupportsCondition(const nsAString& aCondition,
                                  nsIURI* aDocURL,
                                  nsIURI* aBaseURL,
-                                 nsIPrincipal* aDocPrincipal);
+                                 nsIPrincipal* aDocPrincipal,
+                                 mozilla::css::SupportsParsingSettings aSettings
+                                  = mozilla::css::SupportsParsingSettings::Normal);
 
   typedef void (*VariableEnumFunc)(const nsAString&, void*);
 

layout/style/test/stylo-failures.md

@@ -115,7 +115,7 @@ to mochitest command.
 * getComputedStyle style doesn't contain custom properties bug 1336891
   * test_variable_serialization_computed.html [35]
   * test_variables.html `custom property name` [2]
-* test_css_supports.html: issues around @supports syntax servo/servo#15482 [8]
+* test_css_supports.html: issues around @supports syntax servo/servo#15482 [7]
 * test_author_specified_style.html: support serializing color as author specified bug 1348165 [27]
 * browser_newtab_share_rule_processors.js: agent style sheet sharing [1]
 * :visited support (bug 1328509)

layout/style/test/test_css_supports.html

@@ -22,6 +22,7 @@ https://bugzilla.mozilla.org/show_bug.cgi?id=779917
 function runTest()
 {
   var passingConditions = [
+    "color: green",
     "(color: green)",
     "((color: green))",
     "(color: green !important)",
@@ -69,7 +70,6 @@ function runTest()
     "(color: green) or an-extension(that is [unbalanced)",
     "not(unknown: unknown)",
     "(color: green) or(color: blue)",
-    "color: green",
     "(color: green;)",
     "(font-family: 'Helvetica\n",
     "(font-family: 'Helvetica\n')",