CSS: Support omitting semicolon from last property (#14306)

Xamarin.Forms.Core.UnitTests/StyleSheets/StyleParserTests.cs

@@ -0,0 +1,24 @@
+using System.IO;
+using NUnit.Framework;
+
+namespace Xamarin.Forms.StyleSheets.UnitTests
+{
+	[TestFixture]
+	public class StyleParserTests
+	{
+		[TestCase("font-size: 10", 1)]
+		[TestCase("font-size: 10;", 1)]
+		[TestCase("font-size: 10 background-color: blue", 0)]
+		[TestCase("font-size: 10; background-color: blue", 2)]
+		[TestCase("font-size: 10; background-color: blue;", 2)]
+		public void TestCase(string css, int propertyCount)
+		{
+			using (var reader = new StringReader(css))
+			{
+				var parser = Style.Parse(new CssReader(reader));
+
+				Assert.AreEqual(propertyCount, parser.Declarations.Count);
+			}
+		}
+	}
+}

Xamarin.Forms.Core.UnitTests/Xamarin.Forms.Core.UnitTests.csproj

@@ -250,6 +250,7 @@
     <Compile Include="PathSegmentTests.cs" />
     <Compile Include="GeometryTests.cs" />
     <Compile Include="ShellParameterPassingTests.cs" />
+    <Compile Include="StyleSheets\StyleParserTests.cs" />
   </ItemGroup>
   <ItemGroup>
     <ProjectReference Include="..\Xamarin.Forms.Core\Xamarin.Forms.Core.csproj">

Xamarin.Forms.Core/StyleSheets/Style.cs

@@ -21,6 +21,13 @@ namespace Xamarin.Forms.StyleSheets
 			Style style = new Style();
 			string propertyName = null, propertyValue = null;
 
+			void AddAndClearLastDeclaration()
+			{
+				if (!string.IsNullOrEmpty(propertyName) && !string.IsNullOrEmpty(propertyValue))
+					style.Declarations.Add(propertyName, propertyValue);
+				propertyName = propertyValue = null;
+			}
+
 			int p;
 			reader.SkipWhiteSpaces();
 			bool readingName = true;
@@ -35,15 +42,17 @@ namespace Xamarin.Forms.StyleSheets
 						break;
 					case ';':
 						reader.Read();
-						if (!string.IsNullOrEmpty(propertyName) && !string.IsNullOrEmpty(propertyValue))
-							style.Declarations.Add(propertyName, propertyValue);
-						propertyName = propertyValue = null;
+						AddAndClearLastDeclaration();
 						readingName = true;
 						reader.SkipWhiteSpaces();
 						break;
 					default:
 						if ((char)p == stopChar)
+						{
+							AddAndClearLastDeclaration();
+
 							return style;
+						}
 
 						if (readingName)
 						{
@@ -52,10 +61,22 @@ namespace Xamarin.Forms.StyleSheets
 								throw new Exception();
 						}
 						else
-							propertyValue = reader.ReadUntil(stopChar, ';', ':');
+						{
+							propertyValue = reader.ReadUntil(out var limitedBy, stopChar, ';', ':');
+
+							if (limitedBy.HasValue && limitedBy == ':')
+							{
+								style.Declarations.Clear();
+								return style;
+							}
+						}
+
 						break;
 				}
 			}
+
+			AddAndClearLastDeclaration();
+
 			return style;
 		}
 

Xamarin.Forms.Core/StyleSheets/TextReaderExtensions.cs

@@ -55,15 +55,20 @@ namespace Xamarin.Forms.StyleSheets
 			return sb.ToString();
 		}
 
-		public static string ReadUntil(this TextReader reader, params char[] limit)
+		public static string ReadUntil(this TextReader reader, out char? limitedBy, params char[] limit)
 		{
+			limitedBy = null;
+
 			var sb = new StringBuilder();
 			int p;
 			while ((p = reader.Peek()) > 0)
 			{
 				var c = unchecked((char)p);
 				if (limit != null && limit.Contains(c))
+				{
+					limitedBy = c;
 					break;
+				}
 				reader.Read();
 				sb.Append(c);
 			}