Parity: XMLElement.normalizeAdjacentTextNodes…

 - Implement it like Darwin does.
 - Nodes representing CDATA sections now return .kind == .text, like on Darwin.
 - .setChildren() now correctly replaces all children, not just the first.
 - .childCount now returns correct results.

Fixes https://bugs.swift.org/browse/SR-10425

Author: millenomi

CoreFoundation/Parsing.subproj/CFXMLInterface.c

@@ -62,6 +62,7 @@ CFIndex _kCFXMLTypeAttribute = XML_ATTRIBUTE_NODE;
 CFIndex _kCFXMLTypeProcessingInstruction = XML_PI_NODE;
 CFIndex _kCFXMLTypeComment = XML_COMMENT_NODE;
 CFIndex _kCFXMLTypeText = XML_TEXT_NODE;
+CFIndex _kCFXMLTypeCDataSection = XML_CDATA_SECTION_NODE;
 CFIndex _kCFXMLTypeDTD = XML_DTD_NODE;
 CFIndex _kCFXMLDocTypeHTML = XML_DOC_HTML;
 CFIndex _kCFXMLTypeNamespace = 22; // libxml2 does not define namespaces as nodes, so we have to fake it

CoreFoundation/Parsing.subproj/CFXMLInterface.h

@@ -53,6 +53,7 @@ extern CFIndex _kCFXMLTypeAttribute;
 extern CFIndex _kCFXMLTypeProcessingInstruction;
 extern CFIndex _kCFXMLTypeComment;
 extern CFIndex _kCFXMLTypeText;
+extern CFIndex _kCFXMLTypeCDataSection;
 extern CFIndex _kCFXMLTypeDTD;
 extern CFIndex _kCFXMLDocTypeHTML;
 extern CFIndex _kCFXMLTypeNamespace;

Foundation/XMLDTD.swift

@@ -98,6 +98,10 @@ open class XMLDTD : XMLNode {
         }
     }
 
+    open override var childCount: Int {
+        return _CFXMLNodeGetElementChildCount(_xmlNode)
+    }
+    
     /*!
         @method insertChild:atIndex:
         @abstract Inserts a child at a particular index.

Foundation/XMLDocument.swift

@@ -267,6 +267,10 @@ open class XMLDocument : XMLNode {
 
         return XMLNode._objectNodeForNode(rootPtr) as? XMLElement
     }
+    
+    open override var childCount: Int {
+        return _CFXMLNodeGetElementChildCount(_xmlNode)
+    }
 
     /*!
         @method insertChild:atIndex:

Foundation/XMLElement.swift

@@ -323,7 +323,45 @@ open class XMLElement: XMLNode {
         @method normalizeAdjacentTextNodesPreservingCDATA:
         @abstract Adjacent text nodes are coalesced. If the node's value is the empty string, it is removed. This should be called with a value of NO before using XQuery or XPath.
     */
-    open func normalizeAdjacentTextNodesPreservingCDATA(_ preserve: Bool) { NSUnimplemented() }
+    open func normalizeAdjacentTextNodesPreservingCDATA(_ preserve: Bool) {
+        // Replicate Darwin behavior: no change occurs at all in this case.
+        guard childCount != 1 else { return }
+        
+        var text = ""
+        var index = 0
+        let count = childCount
+        var children: [XMLNode] = []
+        
+        while index < count {
+            let child = self.children![index]
+            let isText = child.kind == .text
+            let isCDataToPreserve = preserve ? (isText && child.isCData) : false
+                        
+            if isText && !isCDataToPreserve {
+                if let stringValue = child.stringValue {
+                    text.append(contentsOf: stringValue)
+                }
+            } else {
+                if !text.isEmpty {
+                    let mergedText = XMLNode.text(withStringValue: text) as! XMLNode
+                    children.append(mergedText)
+                    text = ""
+                }
+                if child.kind == .element, let child = child as? XMLElement {
+                    child.normalizeAdjacentTextNodesPreservingCDATA(preserve)
+                }
+                children.append(child)
+            }
+            
+            index += 1
+        }
+        
+        if !text.isEmpty {
+            children.append(XMLNode.text(withStringValue: text) as! XMLNode)
+        }
+        
+        self.setChildren(children)
+    }
 
     internal override class func _objectNodeForNode(_ node: _CFXMLNodePtr) -> XMLElement {
         precondition(_CFXMLNodeGetType(node) == _kCFXMLTypeElement)

Foundation/XMLNode.swift

@@ -315,6 +315,7 @@ open class XMLNode: NSObject, NSCopying {
         case _kCFXMLTypeComment:
             return .comment
 
+        case _kCFXMLTypeCDataSection: fallthrough
         case _kCFXMLTypeText:
             return .text
 
@@ -323,6 +324,10 @@ open class XMLNode: NSObject, NSCopying {
         }
     }
 
+    internal var isCData: Bool {
+        return _CFXMLNodeGetType(_xmlNode) == _kCFXMLTypeCDataSection
+    }
+    
     /*!
      @method name
      @abstract Sets the nodes name. Applicable for element, attribute, namespace, processing-instruction, document type declaration, element declaration, attribute declaration, entity declaration, and notation declaration.
@@ -446,8 +451,8 @@ open class XMLNode: NSObject, NSCopying {
     internal func _removeAllChildren() {
         var nextChild = _CFXMLNodeGetFirstChild(_xmlNode)
         while let child = nextChild {
-            _CFXMLUnlinkNode(child)
             nextChild = _CFXMLNodeGetNextSibling(child)
+            _CFXMLUnlinkNode(child)
         }
         _childNodes.removeAll(keepingCapacity: true)
     }
@@ -558,10 +563,10 @@ open class XMLNode: NSObject, NSCopying {
 
     /*!
      @method childCount
-     @abstract The amount of children, relevant for documents, elements, and document type declarations. Use this instead of [[self children] count].
+     @abstract The amount of children, relevant for documents, elements, and document type declarations.
      */
     open var childCount: Int {
-        return _CFXMLNodeGetElementChildCount(_xmlNode)
+        return self.children?.count ?? 0
     }
 
     /*!

TestFoundation/TestXMLDocument.swift

@@ -685,6 +685,42 @@ class TestXMLDocument : LoopbackServerTest {
         XCTAssertEqual(dtd.systemID, plistDTDUrl)
     }
 
+    func test_parsingCDataSections() throws {
+        let xmlString = """
+           <?xml version="1.0" encoding="utf-8" standalone="yes"?>
+           <content>some text <![CDATA[Some verbatim content! <br> Yep, it's HTML, what are you going to do]]> some more text</content>
+           """
+        
+        do {
+            let doc = try XMLDocument(xmlString: xmlString, options: [])
+            
+            let root = try XCTUnwrap(doc.rootElement())
+            XCTAssertEqual(root.childCount, 3)
+            
+            root.normalizeAdjacentTextNodesPreservingCDATA(false)
+            XCTAssertEqual(root.childCount, 1)
+            XCTAssertEqual(root.children?.first?.stringValue, "some text Some verbatim content! <br> Yep, it's HTML, what are you going to do some more text")
+        }
+        
+        do {
+            let doc = try XMLDocument(xmlString: xmlString, options: [])
+            
+            let root = try XCTUnwrap(doc.rootElement())
+            XCTAssertEqual(root.childCount, 3)
+            
+            let prefix = XMLNode.text(withStringValue: "prefix! ") as! XMLNode
+            root.insertChild(prefix, at: 0)
+            print(root.children!.map { (name: $0.name, kind: $0.kind, stringValue: $0.stringValue ?? "") }.map { String(describing: $0) }.joined(separator: "\n"))
+            
+            root.normalizeAdjacentTextNodesPreservingCDATA(true)
+            XCTAssertEqual(root.childCount, 3)
+            let children = try XCTUnwrap(root.children)
+            XCTAssertEqual(children[0].stringValue, "prefix! some text ")
+            XCTAssertEqual(children[1].stringValue, "Some verbatim content! <br> Yep, it's HTML, what are you going to do")
+            XCTAssertEqual(children[2].stringValue, " some more text")
+        }
+    }
+    
     static var allTests: [(String, (TestXMLDocument) -> () throws -> Void)] {
         return [
             ("test_basicCreation", test_basicCreation),
@@ -719,6 +755,7 @@ class TestXMLDocument : LoopbackServerTest {
             ("test_nodeNames", test_nodeNames),
             ("test_creatingAnEmptyDocumentAndNode", test_creatingAnEmptyDocumentAndNode),
             ("test_creatingAnEmptyDTD", test_creatingAnEmptyDTD),
+            ("test_parsingCDataSections", test_parsingCDataSections),
         ]
     }
 }