Improve CSS parsing: tag/id selector support, fix few issues

Source/svg/CSSParser.swift

@@ -0,0 +1,136 @@
+//
+//  CSSParser.swift
+//  Macaw
+//
+//  Created by Yuri Strot on 10/26/18.
+//
+
+import Foundation
+
+#if !CARTHAGE
+import SWXMLHash
+#endif
+
+enum Selector {
+    case byId(String)
+    case byClass(String)
+    case byTag(String)
+}
+
+class CSSParser {
+
+    fileprivate var stylesByClass: [String: [String: String]] = [:]
+    fileprivate var stylesById: [String: [String: String]] = [:]
+    fileprivate var stylesByTag: [String: [String: String]] = [:]
+
+    func parse(content: String) {
+        let parts = content.components(separatedBy: .whitespacesAndNewlines).joined().split(separator: "{")
+
+        var separatedParts = [String.SubSequence]()
+
+        parts.forEach { substring in
+            separatedParts.append(contentsOf: substring.split(separator: "}"))
+        }
+
+        if separatedParts.count % 2 == 0 {
+
+            let headers = stride(from: 0, to: separatedParts.count, by: 2).map { String(separatedParts[$0]) }
+            let bodies = stride(from: 1, to: separatedParts.count, by: 2).map { separatedParts[$0] }
+
+            for (index, header) in headers.enumerated() {
+                for headerPart in header.split(separator: ",") {
+                    if headerPart.count > 1 {
+                        let selector = parseSelector(text: String(headerPart))
+                        var currentStyles = getStyles(selector: selector)
+                        if (currentStyles == nil) {
+                            currentStyles = [String:String]()
+                        }
+                        let style = String(bodies[index])
+                        let styleParts = style.components(separatedBy: ";")
+                        styleParts.forEach { styleAttribute in
+                            if !styleAttribute.isEmpty {
+                                let currentStyle = styleAttribute.components(separatedBy: ":")
+                                if currentStyle.count == 2 {
+                                    currentStyles![currentStyle[0]] = currentStyle[1]
+                                }
+                            }
+                        }
+                        setStyles(selector: selector, styles: currentStyles!)
+                    }
+                }
+            }
+        }
+    }
+
+    func parseSelector(text: String) -> Selector {
+        if text.first == "#" {
+            return .byId(String(text.dropFirst()))
+        } else if text.first == "." {
+            return .byClass(String(text.dropFirst()))
+        }
+        return .byTag(text)
+    }
+
+    func getStyles(element: SWXMLHash.XMLElement) -> [String: String] {
+        var styleAttributes = [String: String]()
+
+        if let styles = stylesByTag[element.name] {
+            for (att, val) in styles {
+                if styleAttributes.index(forKey: att) == nil {
+                    styleAttributes.updateValue(val, forKey: att)
+                }
+            }
+        }
+
+        if let classNamesString = element.allAttributes["class"]?.text {
+            let classNames = classNamesString.split(separator: " ")
+
+            classNames.forEach { className in
+                let classString = String(className)
+
+                if let styleAttributesFromTable = stylesByClass[classString] {
+                    for (att, val) in styleAttributesFromTable {
+                        if styleAttributes.index(forKey: att) == nil {
+                            styleAttributes.updateValue(val, forKey: att)
+                        }
+                    }
+                }
+            }
+        }
+
+        if let idString = element.allAttributes["id"]?.text {
+            if let styleAttributesFromTable = stylesById[idString] {
+                for (att, val) in styleAttributesFromTable {
+                    if styleAttributes.index(forKey: att) == nil {
+                        styleAttributes.updateValue(val, forKey: att)
+                    }
+                }
+            }
+        }
+
+        return styleAttributes
+    }
+
+    fileprivate func getStyles(selector: Selector) -> [String:String]? {
+        switch selector {
+        case .byId(let id):
+            return stylesById[id]
+        case .byTag(let tag):
+            return stylesByTag[tag]
+        case .byClass(let name):
+            return stylesByClass[name]
+        }
+    }
+
+    fileprivate func setStyles(selector: Selector, styles: [String:String]) {
+        switch selector {
+        case .byId(let id):
+            stylesById[id] = styles
+        case .byTag(let tag):
+            stylesByTag[tag] = styles
+        case .byClass(let name):
+            stylesByClass[name] = styles
+        }
+    }
+
+}

Source/svg/SVGParser.swift

@@ -93,6 +93,8 @@ open class SVGParser {
     fileprivate var defClip = [String: UserSpaceLocus]()
     fileprivate var defEffects = [String: Effect]()
 
+    fileprivate var styles = CSSParser()
+
     fileprivate enum PathCommandType {
         case moveTo
         case lineTo
@@ -234,41 +236,9 @@ open class SVGParser {
         return result
     }
 
-    fileprivate var styleTable: [String: [String: String]] = [:]
-
     fileprivate func parseStyle(_ styleNode: XMLIndexer) {
         if let rawStyle = styleNode.element?.text {
-            let parts = rawStyle.components(separatedBy: .whitespacesAndNewlines).joined().split(separator: "{")
-
-            var separatedParts = [String.SubSequence]()
-
-            parts.forEach { substring in
-                separatedParts.append(contentsOf: substring.split(separator: "}"))
-            }
-
-            if separatedParts.count % 2 == 0 {
-
-                let headers = stride(from: 0, to: separatedParts.count, by: 2).map { String(separatedParts[$0]) }
-                let styles = stride(from: 1, to: separatedParts.count, by: 2).map { separatedParts[$0] }
-
-                for (index, header) in headers.enumerated() {
-                    for headerPart in header.split(separator: ",") {
-                        if headerPart.count > 1 {
-                            let className = String(headerPart.dropFirst())
-                            var classStyles = styleTable[className] != nil ? styleTable[className]! : [String:String]()
-                            let style = String(styles[index].dropLast())
-                            let styleParts = style.components(separatedBy: ";")
-                            styleParts.forEach { styleAttribute in
-                                let currentStyle = styleAttribute.components(separatedBy: ":")
-                                if currentStyle.count == 2 {
-                                    classStyles[currentStyle[0]] = currentStyle[1]
-                                }
-                            }
-                            styleTable[className] = classStyles
-                        }
-                    }
-                }
-            }
+            styles.parse(content: rawStyle)
         }
     }
 
@@ -582,19 +552,9 @@ open class SVGParser {
     fileprivate func getStyleAttributes(_ groupAttributes: [String: String], element: SWXMLHash.XMLElement) -> [String: String] {
         var styleAttributes: [String: String] = groupAttributes
 
-        if let classNamesString = element.allAttributes["class"]?.text {
-            let classNames = classNamesString.split(separator: " ")
-
-            classNames.forEach { className in
-                let classString = String(className)
-
-                if let styleAttributesFromTable = styleTable[classString] {
-                    for (att, val) in styleAttributesFromTable {
-                        if styleAttributes.index(forKey: att) == nil {
-                            styleAttributes.updateValue(val, forKey: att)
-                        }
-                    }
-                }
+        for (att, val) in styles.getStyles(element: element) {
+            if styleAttributes.index(forKey: att) == nil {
+                styleAttributes.updateValue(val, forKey: att)
             }
         }