support function in custom paint input arguments

third_party/WebKit/Source/core/css/parser/CSSPropertyParserHelpers.cpp

Index: third_party/WebKit/Source/core/css/parser/CSSPropertyParserHelpers.cpp
diff --git a/third_party/WebKit/Source/core/css/parser/CSSPropertyParserHelpers.cpp b/third_party/WebKit/Source/core/css/parser/CSSPropertyParserHelpers.cpp
index ed502005d576616f98a37ef741888b1540a603e0..7562bfc98f6b48a09134d25594df430cb66d97b0 100644
--- a/third_party/WebKit/Source/core/css/parser/CSSPropertyParserHelpers.cpp
+++ b/third_party/WebKit/Source/core/css/parser/CSSPropertyParserHelpers.cpp
@@ -41,6 +41,26 @@ bool addCSSPaintArgument(const Vector<CSSParserToken>& tokens,
   return false;
 }
 
+// Consume input arguments, if encounter function, will return the function
+// block as a Vector of CSSParserToken, otherwise, will just return a Vector of
+// a single CSSParserToken.
+Vector<CSSParserToken> consumeFunctionArgsOrNot(CSSParserTokenRange& args) {
+  Vector<CSSParserToken> argumentTokens;
+  if (args.peek().getBlockType() != CSSParserToken::BlockStart) {

[meade_UTC10, 2017/02/17 06:40:04]

Let's flip the if statement order - It's usually clearer to do

if (condition) {
  // conditionalFoo
} else {
  // notConditonalFoo
}

than

if (!condition) {
  // NotConditionalFoo
} else {
  // conditionalFoo
}

[renjieliu1, 2017/02/19 04:57:58]

Done.

+    argumentTokens.push_back(args.consumeIncludingWhitespace());
+  } else {
+    // Encounter function block.

[meade_UTC10, 2017/02/17 06:40:04]

Incidentally, what does it mean to have got here, but not be encountering a
function block?

[renjieliu1, 2017/02/19 04:57:58]

I think if it is not a function but got here, in the variable resolving phase,
it will fail, but since we don't have knowledge about the argument types here,
we can't check anything here

[meade_UTC10, 2017/02/22 06:56:22]

Could you please add that as a comment? It still seems a bit mysterious if
you're just reading the code :)

+    argumentTokens.push_back(args.peek());

[meade_UTC10, 2017/02/17 06:40:04]

Perhaps, then, a comment to explain this?

if (args.peek().getBlockType() == CSSParserToken::BlockStart) {
  // Function block.
  // Push the function name and initial brace.
  argumentTokens.push_back(args.peek());
  CSSParserTokenRange contents = args.consumeBlock();
  while (!contents.atEnd()) {
     // Push function arguments
     argumentTokens.push_back(contents.consume());
  }
  argumentTokens.push_back(
      CSSParserToken(RightParenthesisToken, CSSParserToken::BlockEnd));
} else {
...
}

[renjieliu1, 2017/02/19 04:57:58]

thank you for the suggestion!

+    CSSParserTokenRange contents = args.consumeBlock();
+    while (!contents.atEnd()) {
+      argumentTokens.push_back(contents.consume());
+    }
+    argumentTokens.push_back(
+        CSSParserToken(RightParenthesisToken, CSSParserToken::BlockEnd));
+  }
+  return argumentTokens;
+}
+
 }  // namespace
 
 void complete4Sides(CSSValue* side[4]) {
@@ -1165,15 +1185,14 @@ static CSSValue* consumePaint(CSSParserTokenRange& args,
   if (!consumeCommaIncludingWhitespace(args))
     return nullptr;
 
-  // Consume arguments. Currently does not support complicated arguments
-  // like function calls.
+  // Consume arguments.
   // TODO(renjieliu): We may want to optimize the implementation by resolve
   // variables early if paint function is registered.
   Vector<CSSParserToken> argumentTokens;
   Vector<RefPtr<CSSVariableData>> variableData;
   while (!args.atEnd()) {
     if (args.peek().type() != CommaToken) {
-      argumentTokens.push_back(args.consumeIncludingWhitespace());
+      argumentTokens.appendVector(consumeFunctionArgsOrNot(args));
     } else {
       if (!addCSSPaintArgument(argumentTokens, &variableData))
         return nullptr;