Fix inline code being rendered as blocks. (#5017)

* Fix inline code being rendered as blocks.

And make blocks non-greedy as well as only scrolling when needed.

* Rename the bubble layout priorities.

* Add an InlineCode attribute so that the builder also strips links from these too.

* Split up the snapshot tests into individual cases.

This should make it much easier to see *what* has changed when regenerating.

ElementX/Sources/Other/HTMLParsing/AttributedStringBuilder.swift

@@ -32,6 +32,7 @@ extension NSAttributedString.Key {
     static let MatrixEventOnRoomAlias: NSAttributedString.Key = .init(rawValue: EventOnRoomAliasAttribute.name)
     static let MatrixAllUsersMention: NSAttributedString.Key = .init(rawValue: AllUsersMentionAttribute.name)
     static let CodeBlock: NSAttributedString.Key = .init(rawValue: CodeBlockAttribute.name)
+    static let InlineCode: NSAttributedString.Key = .init(rawValue: InlineCodeAttribute.name)
 }
 
 struct AttributedStringBuilder: AttributedStringBuilderProtocol {
@@ -197,15 +198,24 @@ struct AttributedStringBuilder: AttributedStringBuilderProtocol {
                 content.addAttribute(.MatrixBlockquote, value: true, range: NSRange(location: 0, length: content.length))
                 
             case "code", "pre":
-                let preserveFormatting = preserveFormatting || tag == "pre"
+                let isCodeBlock = tag == "pre"
+                
+                let preserveFormatting = preserveFormatting || isCodeBlock
                 content = attributedString(element: childElement, documentBody: documentBody, preserveFormatting: preserveFormatting, listTag: listTag, listIndex: &childIndex, indentLevel: indentLevel)
                 
                 let fontPointSize = fontPointSize * 0.9 // Intentionally shrink code blocks by 10%
                 content.setFontPreservingSymbolicTraits(UIFont.monospacedSystemFont(ofSize: fontPointSize, weight: .regular))
                 
-                content.addAttribute(.CodeBlock, value: true, range: NSRange(location: 0, length: content.length))
+                if isCodeBlock {
+                    content.addAttribute(.CodeBlock, value: true, range: NSRange(location: 0, length: content.length))
+                    // The scroll view provides the background colour for code blocks.
+                } else {
+                    content.addAttribute(.InlineCode, value: true, range: NSRange(location: 0, length: content.length))
+                    // But inline code is (obviously) inline so it's much easier to set the background colour here.
+                    content.addAttribute(.backgroundColor, value: UIColor.compound._bgCodeBlock as Any, range: NSRange(location: 0, length: content.length))
+                }
                 
-                // Don't allow identifiers or links in code blocks
+                // Don't allow identifiers or links in code.
                 content.removeAttribute(.MatrixRoomID, range: NSRange(location: 0, length: content.length))
                 content.removeAttribute(.MatrixRoomAlias, range: NSRange(location: 0, length: content.length))
                 content.removeAttribute(.MatrixUserID, range: NSRange(location: 0, length: content.length))
@@ -353,14 +363,15 @@ struct AttributedStringBuilder: AttributedStringBuilderProtocol {
         // Sort the links by length so the longest one always takes priority
         matches.sorted { $0.range.length > $1.range.length }.forEach { [attributedString] match in
             // Don't highlight links within codeblocks
-            let isInCodeBlock = attributedString.attribute(.CodeBlock, at: match.range.location, effectiveRange: nil) != nil
-            if isInCodeBlock {
+            let isCode = attributedString.attribute(.CodeBlock, at: match.range.location, effectiveRange: nil) != nil
+                || attributedString.attribute(.InlineCode, at: match.range.location, effectiveRange: nil) != nil
+            if isCode {
                 return
             }
             
             var hasLink = false
             attributedString.enumerateAttribute(.link, in: match.range, options: []) { value, _, stop in
-                if value != nil, !isInCodeBlock {
+                if value != nil, !isCode {
                     hasLink = true
                     stop.pointee = true
                 }

ElementX/Sources/Other/HTMLParsing/ElementXAttributeScope.swift

@@ -68,6 +68,11 @@ enum CodeBlockAttribute: AttributedStringKey {
     static let name = "MXCodeBlockAttribute"
 }
 
+enum InlineCodeAttribute: AttributedStringKey {
+    typealias Value = Bool
+    static let name = "MXInlineCodeAttribute"
+}
+
 // periphery: ignore - required to make NSAttributedString to AttributedString conversion even if not used directly
 extension AttributeScopes {
     struct ElementXAttributes: AttributeScope {
@@ -84,6 +89,7 @@ extension AttributeScopes {
         let allUsersMention: AllUsersMentionAttribute
         
         let codeBlock: CodeBlockAttribute
+        let inlineCode: InlineCodeAttribute
         
         let swiftUI: SwiftUIAttributes
         let uiKit: UIKitAttributes

ElementX/Sources/Other/HTMLParsing/HTMLFixtures.swift

@@ -15,7 +15,8 @@ enum HTMLFixtures: String, CaseIterable {
     case textFormatting
     case groupedBlockQuotes
     case separatedBlockQuotes
-    case codeBlocks
+    case code
+    case wideCodeBlock
     case unorderedList
     case orderedList
     
@@ -74,9 +75,9 @@ enum HTMLFixtures: String, CaseIterable {
             <blockquote>Some other blockquote</blockquote>\
             Text after second blockquote
             """
-        case .codeBlocks:
+        case .code:
             """
-            <pre>A preformatted code block
+            <pre>A pre-formatted code block
             <code>struct ContentView: View {
                 var body: some View {
                     VStack {
@@ -88,11 +89,17 @@ enum HTMLFixtures: String, CaseIterable {
                     .padding()
                 }
             }</code></pre></br>
-            Followed by some plain code blocks</br>
-            <code>Hello, world!</code>
-            <code><b>Hello</b>, <i>world!</i></code>
-            <code><a href="https://www.matrix.org">This link should not be interpreted as such</a></code>
-            <code>And this https://www.matrix.org should be not highlighted</code>
+            Followed by some inline code</br>
+            <p>Plain text <code>code here</code> more text</p>
+            <p><code>Hello, world!</code></p>
+            <p><code><b>Hello</b>, <i>world!</i></code></p>
+            <p><code>&lt;b&gt;Hello&lt;/b&gt;, &lt;i&gt;world!&lt;/i&gt;</code></p>
+            <p><code><a href="https://www.matrix.org">This link should not be interpreted as such</a></code></p>
+            <p><code>And this https://www.matrix.org should be not highlighted</code></p>
+            """
+        case .wideCodeBlock:
+            """
+            <pre><code>CHHapticPattern.mm:487   +[CHHapticPattern patternForKey:error:]: Failed to read pattern library data: Error Domain=NSCocoaErrorDomain Code=260 "The file “hapticpatternlibrary.plist” couldn’t be opened because there is no such file." UserInfo={NSFilePath=/Library/Audio/Tunings/Generic/Haptics/Library/hapticpatternlibrary.plist, NSURL=file:///Library/Audio/Tunings/Generic/Haptics/Library/hapticpatternlibrary.plist, NSUnderlyingError=0x600000da69d0 {Error Domain=NSPOSIXErrorDomain Code=2 "No such file or directory"}}</code></pre>
             """
         case .unorderedList:
             """