[Xamarin.Android.Tools.AndroidSdk] Probe for Microsoft OpenJDK dirs

Author: jonpryor

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

@@ -287,6 +287,7 @@ public static IEnumerable<JdkInfo> GetKnownSystemJdkInfos (Action<TraceLevel, st
 			return GetEnvironmentVariableJdks ("JI_JAVA_HOME", logger)
 				.Concat (GetWindowsJdks (logger))
 				.Concat (GetConfiguredJdks (logger))
+				.Concat (GetMacOSMicrosoftOpenJdks (logger))
 				.Concat (GetMacOSMicrosoftJdks (logger))
 				.Concat (GetEnvironmentVariableJdks ("JAVA_HOME", logger))
 				.Concat (GetPathEnvironmentJdks (logger))
@@ -313,6 +314,32 @@ static IEnumerable<string> GetConfiguredJdkPaths (Action<TraceLevel, string> log
 			}
 		}
 
+		internal static IEnumerable<JdkInfo> GetMacOSMicrosoftOpenJdks (Action<TraceLevel, string> logger)
+		{
+			return GetMacOSMicrosoftOpenJdkPaths ()
+				.Select (p => TryGetJdkInfo (p, logger, "/Library/Java/JavaVirtualMachines/microsoft-*.jdk"))
+				.Where (jdk => jdk != null)
+				.Select (jdk => jdk!)
+				.OrderByDescending (jdk => jdk, JdkInfoVersionComparer.Default);
+		}
+
+		static IEnumerable<string> GetMacOSMicrosoftOpenJdkPaths ()
+		{
+			var jdk     = AppDomain.CurrentDomain.GetData ($"GetMacOSMicrosoftOpenJdkPath override! {typeof (JdkInfo).AssemblyQualifiedName}")
+				?.ToString ();
+			if (jdk != null) {
+				yield return jdk;
+				yield break;
+			}
+			const string JVMs = "/Library/Java/JavaVirtualMachines";
+			foreach (var dir in Directory.EnumerateDirectories (JVMs, "microsoft-*.jdk")) {
+				var home = Path.Combine (dir, "Contents", "Home");
+				if (!Directory.Exists (home))
+					continue;
+				yield return home;
+			}
+		}
+
 		internal static IEnumerable<JdkInfo> GetMacOSMicrosoftJdks (Action<TraceLevel, string> logger)
 		{
 			return GetMacOSMicrosoftJdkPaths ()

src/Xamarin.Android.Tools.AndroidSdk/Sdks/AndroidSdkWindows.cs

@@ -131,7 +131,8 @@ IEnumerable<JdkInfo> ToJdkInfos (IEnumerable<string> paths, string locator)
 			}
 
 			return ToJdkInfos (GetPreferredJdkPaths (), "Preferred Registry")
-				.Concat (ToJdkInfos (GetOpenJdkPaths (), "OpenJDK"))
+				.Concat (ToJdkInfos (GetMicrosoftOpenJdkPaths (), "Microsoft OpenJDK"))
+				.Concat (ToJdkInfos (GetVSAndroidJdkPaths (), @"HKLM\SOFTWARE\Microsoft\VisualStudio\Android@JavaHome"))
 				.Concat (ToJdkInfos (GetKnownOpenJdkPaths (), "Well-known OpenJDK paths"))
 				.Concat (ToJdkInfos (GetOracleJdkPaths (), "Oracle JDK"))
 				;
@@ -150,7 +151,7 @@ private static IEnumerable<string> GetPreferredJdkPaths ()
 			}
 		}
 
-		private static IEnumerable<string> GetOpenJdkPaths ()
+		private static IEnumerable<string> GetVSAndroidJdkPaths ()
 		{
 			var root = RegistryEx.LocalMachine;
 			var wows = new[] { RegistryEx.Wow64.Key32, RegistryEx.Wow64.Key64 };
@@ -162,6 +163,54 @@ private static IEnumerable<string> GetOpenJdkPaths ()
 					yield return RegistryEx.GetValueString (root, subKey, valueName, wow) ?? "";
 			}
 		}
+		private static IEnumerable<string> GetMicrosoftOpenJdkPaths ()
+		{
+			const string JdkFolderNamePrefix = "jdk-";
+
+			var paths = new List<Tuple<string, Version>> ();
+			var rootPaths = new List<string> {
+				Path.Combine (Environment.ExpandEnvironmentVariables ("%ProgramW6432%"), "Microsoft"),
+				Path.Combine (Environment.GetFolderPath (Environment.SpecialFolder.ProgramFilesX86), "Android", "jdk"),
+			};
+
+			foreach (var rootPath in rootPaths) {
+				if (!Directory.Exists (rootPath))
+					continue;
+				foreach (var directoryName in Directory.EnumerateDirectories (rootPath, $"{JdkFolderNamePrefix}*").ToList ()) {
+					var version = ExtractVersion (directoryName, JdkFolderNamePrefix);
+					if (version == null)
+						continue;
+					paths.Add (Tuple.Create (directoryName, version));
+				}
+			}
+
+			return paths.OrderByDescending (v => v.Item2)
+				.Where (openJdk => ProcessUtils.FindExecutablesInDirectory (Path.Combine (openJdk.Item1, "bin"), _JarSigner).Any ())
+				.Select (openJdk => openJdk.Item1);
+		}
+
+		static Version? ExtractVersion (string path, string prefix)
+		{
+			var name = Path.GetFileName (path);
+			if (name.Length <= prefix.Length)
+				return null;
+			if (!name.StartsWith (prefix, StringComparison.OrdinalIgnoreCase))
+				return null;
+
+			name    = name.Substring (prefix.Length);
+			int end = 0;
+			while (end < name.Length &&
+					(char.IsDigit (name [end]) || name [end] == '.'))
+				end++;
+
+			do {
+				if (Version.TryParse (name.Substring (0, end), out var v))
+					return v;
+				end = name.LastIndexOf ('.', end);
+			} while (end > 0);
+
+			return null;
+		}
 
 		/// <summary>
 		/// Locate OpenJDK installations by well known path.