Implement querySelectorAll for element selection

include/lunasvg.h

@@ -649,6 +649,8 @@ class LUNASVG_API Element : public Node {
     friend class Document;
 };
 
+using ElementList = std::vector<Element>;
+
 class SVGRootElement;
 
 class LUNASVG_API Document {
@@ -688,6 +690,13 @@ class LUNASVG_API Document {
      */
     void applyStyleSheet(const std::string& content);
 
+    /**
+     * @brief Selects all elements that match the given CSS selector(s).
+     * @param content A string containing the CSS selector(s) to match elements.
+     * @return A list of elements matching the selector(s).
+     */
+    ElementList querySelectorAll(const std::string& content) const;
+
     /**
      * @brief Returns the intrinsic width of the document in pixels.
      * @return The width of the document.

source/svgparser.cpp

@@ -461,11 +461,11 @@ static bool parseCombinator(std::string_view& input, SimpleSelector::Combinator&
         input.remove_prefix(1);
     }
 
-    if(skipDelimiter(input, '>'))
+    if(skipDelimiterAndOptionalSpaces(input, '>'))
         combinator = SimpleSelector::Combinator::Child;
-    else if(skipDelimiter(input, '+'))
+    else if(skipDelimiterAndOptionalSpaces(input, '+'))
         combinator = SimpleSelector::Combinator::DirectAdjacent;
-    else if(skipDelimiter(input, '~'))
+    else if(skipDelimiterAndOptionalSpaces(input, '~'))
         combinator = SimpleSelector::Combinator::InDirectAdjacent;
     return combinator != SimpleSelector::Combinator::None;
 }
@@ -479,7 +479,7 @@ static bool parseSelector(std::string_view& input, Selector& selector)
         if(!parseSimpleSelector(input, simpleSelector, failed))
             return !failed && (combinator == SimpleSelector::Combinator::Descendant);
         selector.push_back(std::move(simpleSelector));
-    } while(parseCombinator(input, combinator) && skipOptionalSpaces(input));
+    } while(parseCombinator(input, combinator));
     return true;
 }
 
@@ -490,7 +490,7 @@ static bool parseSelectors(std::string_view& input, SelectorList& selectors)
         if(!parseSelector(input, selector))
             return false;
         selectors.push_back(std::move(selector));
-    } while(skipDelimiter(input, ',') && skipOptionalSpaces(input));
+    } while(skipDelimiterAndOptionalSpaces(input, ','));
     return true;
 }
 
@@ -580,6 +580,18 @@ static RuleDataList parseStyleSheet(std::string_view input)
     return rules;
 }
 
+static SelectorList parseQuerySelectors(std::string_view input)
+{
+    SelectorList selectors;
+    stripLeadingAndTrailingSpaces(input);
+    if(!parseSelectors(input, selectors)
+        || !input.empty()) {
+        return SelectorList();
+    }
+
+    return selectors;
+}
+
 inline void parseInlineStyle(std::string_view input, SVGElement* element)
 {
     std::string name;
@@ -909,4 +921,22 @@ void Document::applyStyleSheet(const std::string& content)
     }
 }
 
+ElementList Document::querySelectorAll(const std::string& content) const
+{
+    auto selectors = parseQuerySelectors(content);
+    if(selectors.empty())
+        return ElementList();
+    ElementList elements;
+    m_rootElement->transverse([&](SVGElement* element) {
+        for(const auto& selector : selectors) {
+            if(matchSelector(selector, element)) {
+                elements.push_back(element);
+                break;
+            }
+        }
+    });
+
+    return elements;
+}
+
 } // namespace lunasvg

source/svgparserutils.h

@@ -57,6 +57,17 @@ constexpr bool skipOptionalSpacesOrComma(std::string_view& input)
     return skipOptionalSpacesOrDelimiter(input, ',');
 }
 
+constexpr bool skipDelimiterAndOptionalSpaces(std::string_view& input, char delimiter)
+{
+    if(!input.empty() && input.front() == delimiter) {
+        input.remove_prefix(1);
+        skipOptionalSpaces(input);
+        return true;
+    }
+
+    return false;
+}
+
 constexpr bool skipDelimiter(std::string_view& input, char delimiter)
 {
     if(!input.empty() && input.front() == delimiter) {