Add AndroidSdkInfo.DetectAndSetPreferredJavaSdkPathToLatest() (#35)

Context: https://paper.dropbox.com/doc/OpenJDK-and-You--AH1yWKdVXgno~uXYfmcUAZTwAg-NoECAe2XkBQeoxFfGL6ea

Add `AndroidSdkInfo.DetectAndSetPreferredJavaSdkPathToLatest()`.

Author: jonpryor

src/Xamarin.Android.Tools.AndroidSdk/AndroidSdkInfo.cs

@@ -171,5 +171,20 @@ public static void SetPreferredJavaSdkPath (string path, Action<TraceLevel, stri
 			var sdk = CreateSdk (logger);
 			sdk.SetPreferredJavaSdkPath (path);
 		}
+
+		public static void DetectAndSetPreferredJavaSdkPathToLatest (Action<TraceLevel, string> logger = null)
+		{
+			if (OS.IsWindows)
+				throw new NotImplementedException ("Windows is not supported at this time.");
+
+			logger          = logger ?? DefaultConsoleLogger;
+
+			var latestJdk   = JdkInfo.GetMacOSMicrosoftJdks (logger).FirstOrDefault ();
+			if (latestJdk == null)
+				throw new NotSupportedException ("No Microsoft OpenJDK could be found.  Please re-run the Visual Studio installer or manually specify the JDK path in settings.");
+
+			var sdk = CreateSdk (logger);
+			sdk.SetPreferredJavaSdkPath (latestJdk.HomePath);
+		}
 	}
 }

src/Xamarin.Android.Tools.AndroidSdk/JdkInfo.cs

@@ -236,7 +236,7 @@ static IEnumerable<string> GetConfiguredJdkPaths (Action<TraceLevel, string> log
 			}
 		}
 
-		static IEnumerable<JdkInfo> GetMacOSMicrosoftJdks (Action<TraceLevel, string> logger)
+		internal static IEnumerable<JdkInfo> GetMacOSMicrosoftJdks (Action<TraceLevel, string> logger)
 		{
 			return GetMacOSMicrosoftJdkPaths ()
 				.Select (p => TryGetJdkInfo (p, logger))
@@ -246,8 +246,12 @@ static IEnumerable<JdkInfo> GetMacOSMicrosoftJdks (Action<TraceLevel, string> lo
 
 		static IEnumerable<string> GetMacOSMicrosoftJdkPaths ()
 		{
-			var home    = Environment.GetFolderPath (Environment.SpecialFolder.Personal);
-			var jdks    = Path.Combine (home, "Library", "Developer", "Xamarin", "jdk");
+			var jdks    = AppDomain.CurrentDomain.GetData ($"GetMacOSMicrosoftJdkPaths jdks override! {typeof (JdkInfo).AssemblyQualifiedName}")
+				?.ToString ();
+			if (jdks == null) {
+				var home    = Environment.GetFolderPath (Environment.SpecialFolder.Personal);
+				jdks        = Path.Combine (home, "Library", "Developer", "Xamarin", "jdk");
+			}
 			if (!Directory.Exists (jdks))
 				return Enumerable.Empty <string> ();
 

src/Xamarin.Android.Tools.AndroidSdk/Tests/AndroidSdkInfoTests.cs

@@ -3,6 +3,7 @@
 using System.Diagnostics;
 using System.IO;
 using System.Text;
+using System.Xml.Linq;
 
 using NUnit.Framework;
 
@@ -160,5 +161,56 @@ protected void Exec (string exe, string args)
 				proc.WaitForExit ();
 			}
 		}
+
+		[Test]
+		public void DetectAndSetPreferredJavaSdkPathToLatest ()
+		{
+			Action<TraceLevel, string> logger = (level, message) => {
+				Console.WriteLine ($"[{level}] {message}");
+			};
+			var jdks    = Path.GetTempFileName ();
+			File.Delete (jdks);
+			Directory.CreateDirectory (jdks);
+			AppDomain.CurrentDomain.SetData ($"GetMacOSMicrosoftJdkPaths jdks override! {typeof (JdkInfo).AssemblyQualifiedName}", jdks);
+
+			var backupConfig    = UnixConfigPath + "." + Path.GetRandomFileName ();
+			try {
+				if (OS.IsWindows) {
+					Assert.Throws<NotImplementedException>(() => AndroidSdkInfo.DetectAndSetPreferredJavaSdkPathToLatest (logger));
+					return;
+				}
+				Assert.Throws<NotSupportedException>(() => AndroidSdkInfo.DetectAndSetPreferredJavaSdkPathToLatest (logger));
+				var newJdkPath  = Path.Combine (jdks, "microsoft_dist_openjdk_1.8.999");
+				JdkInfoTests.CreateFauxJdk (newJdkPath, "1.8.999");
+
+				if (File.Exists (UnixConfigPath))
+					File.Move (UnixConfigPath, backupConfig);
+
+				AndroidSdkInfo.DetectAndSetPreferredJavaSdkPathToLatest (logger);
+				AssertJdkPath (newJdkPath);
+			}
+			finally {
+				AppDomain.CurrentDomain.SetData ($"GetMacOSMicrosoftJdkPaths jdks override! {typeof (JdkInfo).AssemblyQualifiedName}", null);
+				Directory.Delete (jdks, recursive: true);
+				if (File.Exists (backupConfig))
+					File.Move (backupConfig, UnixConfigPath);
+			}
+		}
+
+		static void AssertJdkPath (string expectedJdkPath)
+		{
+			var config_file     = XDocument.Load (UnixConfigPath);
+			var javaEl          = config_file.Root.Element ("java-sdk");
+			var actualJdkPath   = (string) javaEl.Attribute ("path");
+
+			Assert.AreEqual (expectedJdkPath, actualJdkPath);
+		}
+
+		static string UnixConfigPath {
+			get {
+				var p = Environment.GetFolderPath (Environment.SpecialFolder.ApplicationData);
+				return Path.Combine (Path.Combine (p, "xbuild"), "monodroid-config.xml");
+			}
+		}
 	}
 }

src/Xamarin.Android.Tools.AndroidSdk/Tests/JdkInfoTests.cs

@@ -34,10 +34,18 @@ public void CreateFauxJdk ()
 		{
 			var dir = Path.GetTempFileName();
 			File.Delete (dir);
+
+			CreateFauxJdk (dir, "1.2.3.4");
+
+			FauxJdkDir = dir;
+		}
+
+		internal static void CreateFauxJdk (string dir, string version)
+		{
 			Directory.CreateDirectory (dir);
 
 			using (var release = new StreamWriter (Path.Combine (dir, "release"))) {
-				release.WriteLine ("JAVA_VERSION=\"1.2.3.4\"");
+				release.WriteLine ($"JAVA_VERSION=\"{version}\"");
 			}
 
 			var bin = Path.Combine (dir, "bin");
@@ -56,8 +64,6 @@ public void CreateFauxJdk ()
 			CreateShellScript (Path.Combine (dir, "jli", "libjli.dylib"), "");
 			CreateShellScript (Path.Combine (jre, "libjvm.so"), "");
 			CreateShellScript (Path.Combine (jre, "jvm.dll"), "");
-
-			FauxJdkDir = dir;
 		}
 
 		[OneTimeTearDown]