[Xamarin.Android.Tools.AndroidSdk] Probe for Zulu JDK (#114)

Context: https://www.azul.com/downloads/zulu-community/
Commit 237642c removed support for the ancient
`microsoft_dist_openjdk_*` versions, replacing it with the newer
[Microsoft OpenJDK][0].
One problem with this change is one of *compatibility*:
`microsoft_dist_openjdk_` was a build of JDK 1.8, while
Microsoft OpenJDK only provides builds for JDK 11 and later.
This is a problem, as the [Visual Studio Android Designer][1]
currently requires JDK 1.8, and is not yet compatible with JDK 11.
Add support to probe for for [Azul Zulu OpenJDK][2] installation
directories, as Zulu provides updated JDK 1.8 installers.
Additionally, refactor and centralize the JDK Location logic.
Previously, `JdkInfo.GetKnownSystemJdkInfos()` would return all of
the Windows installation locations before the macOS/Linux/etc.
locations, which made it possible for Windows and non-Windows
platforms to return paths in an inconsistent order. Introduce a new
`JdkLocations` helper, and add new subclasses for each specific JDK
location, so that `JdkInfo.GetKnownSystemJdkInfos()` can be *unified*
across macOS/Linux & Windows, increasing consistency.
Add a new `tools/ls-jdks` tool, to make it easier to print all probed
JDK locations.
[0]: https://www.microsoft.com/openjdk
[1]: https://docs.microsoft.com/en-us/xamarin/android/user-interface/android-designer/designer-walkthrough?tabs=windows
[2]: https://www.azul.com/downloads/zulu-community/?package=jdk

Author: jonpryor

Xamarin.Android.Tools.sln

@@ -1,4 +1,4 @@
-Microsoft Visual Studio Solution File, Format Version 12.00
+Microsoft Visual Studio Solution File, Format Version 12.00
 # Visual Studio Version 16
 VisualStudioVersion =16.0.30709.64
 MinimumVisualStudioVersion =10.0.40219.1
@@ -10,6 +10,10 @@ Project("{9A19103F-16F7-4668-BE54-9A1E7A4F7556}") = "Microsoft.Android.Build.Bas
 EndProject
 Project("{FAE04EC0-301F-11D3-BF4B-00C04F79EFBC}") = "Microsoft.Android.Build.BaseTasks-Tests", "tests\Microsoft.Android.Build.BaseTasks-Tests\Microsoft.Android.Build.BaseTasks-Tests.csproj", "{4F5FD01C-B5A6-4F9F-91CE-3E78B3F942AC}"
 EndProject
+Project("{2150E333-8FDC-42A3-9474-1A3956D46DE8}") = "tools", "tools", "{19FE1B44-DB71-4F97-A07E-085888690DAE}"
+EndProject
+Project("{FAE04EC0-301F-11D3-BF4B-00C04F79EFBC}") = "ls-jdks", "tools\ls-jdks\ls-jdks.csproj", "{3D2ADF77-62C7-4E0E-AB29-BDD266B7D56D}"
+EndProject
 Global
 GlobalSection(SolutionConfigurationPlatforms) = preSolution
 Debug|Any CPU = Debug|Any CPU
@@ -32,11 +36,18 @@ Global
 {4F5FD01C-B5A6-4F9F-91CE-3E78B3F942AC}.Debug|Any CPU.Build.0 = Debug|Any CPU
 {4F5FD01C-B5A6-4F9F-91CE-3E78B3F942AC}.Release|Any CPU.ActiveCfg = Release|Any CPU
 {4F5FD01C-B5A6-4F9F-91CE-3E78B3F942AC}.Release|Any CPU.Build.0 = Release|Any CPU
+{3D2ADF77-62C7-4E0E-AB29-BDD266B7D56D}.Debug|Any CPU.ActiveCfg = Debug|Any CPU
+{3D2ADF77-62C7-4E0E-AB29-BDD266B7D56D}.Debug|Any CPU.Build.0 = Debug|Any CPU
+{3D2ADF77-62C7-4E0E-AB29-BDD266B7D56D}.Release|Any CPU.ActiveCfg = Release|Any CPU
+{3D2ADF77-62C7-4E0E-AB29-BDD266B7D56D}.Release|Any CPU.Build.0 = Release|Any CPU
 EndGlobalSection
 GlobalSection(SolutionProperties) = preSolution
 HideSolutionNode =FALSE
 EndGlobalSection
 GlobalSection(ExtensibilityGlobals) = postSolution
 SolutionGuid ={BA1CD771-F00B-4DE8-93EE-7690D81F6A5A}
 EndGlobalSection
+GlobalSection(NestedProjects) = preSolution
+{3D2ADF77-62C7-4E0E-AB29-BDD266B7D56D} = {19FE1B44-DB71-4F97-A07E-085888690DAE}
+EndGlobalSection
 EndGlobal

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

@@ -185,7 +185,7 @@ public static void DetectAndSetPreferredJavaSdkPathToLatest (Action<TraceLevel,
 
 logger=logger??DefaultConsoleLogger;
 
-varlatestJdk=JdkInfo.GetMicrosoftOpenJdks(logger).FirstOrDefault();
+varlatestJdk=MicrosoftOpenJdkLocations.GetMicrosoftOpenJdks(logger).FirstOrDefault();
 if(latestJdk==null)
 thrownewNotSupportedException("No Microsoft OpenJDK could be found. Please re-run the Visual Studio installer or manually specify the JDK path in settings.");
 

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

@@ -285,78 +285,20 @@ public static IEnumerable<JdkInfo> GetKnownSystemJdkInfos (Action<TraceLevel, st
 logger=logger??AndroidSdkInfo.DefaultConsoleLogger;
 
 returnGetEnvironmentVariableJdks("JI_JAVA_HOME",logger)
-.Concat(GetWindowsJdks(logger))
-.Concat(GetConfiguredJdks(logger))
-.Concat(GetMacOSMicrosoftOpenJdks(logger))
+.Concat(JdkLocations.GetPreferredJdks(logger))
+.Concat(XAPrepareJdkLocations.GetXAPrepareJdks(logger))
+.Concat(MicrosoftOpenJdkLocations.GetMicrosoftOpenJdks(logger))
+.Concat(AzulJdkLocations.GetAzulJdks(logger))
+.Concat(OracleJdkLocations.GetOracleJdks(logger))
+.Concat(VSAndroidJdkLocations.GetVSAndroidJdks(logger))
 .Concat(GetEnvironmentVariableJdks("JAVA_HOME",logger))
 .Concat(GetPathEnvironmentJdks(logger))
 .Concat(GetLibexecJdks(logger))
 .Concat(GetJavaAlternativesJdks(logger))
 ;
 }
 
-staticIEnumerable<JdkInfo>GetConfiguredJdks(Action<TraceLevel,string>logger)
-{
-returnGetConfiguredJdkPaths(logger)
-.Select(p =>TryGetJdkInfo(p,logger,"monodroid-config.xml"))
-.Where(jdk =>jdk!=null)
-.Select(jdk =>jdk!)
-.OrderByDescending(jdk =>jdk,JdkInfoVersionComparer.Default);
-}
-
-staticIEnumerable<string>GetConfiguredJdkPaths(Action<TraceLevel,string>logger)
-{
-varconfig=AndroidSdkUnix.GetUnixConfigFile(logger);
-foreach(varjava_sdkinconfig.Root.Elements("java-sdk")){
-varpath=(string)java_sdk.Attribute("path");
-yieldreturnpath;
-}
-}
-
-internalstaticIEnumerable<JdkInfo>GetMicrosoftOpenJdks(Action<TraceLevel,string>logger)
-{
-foreach(vardirinGetMacOSMicrosoftOpenJdks(logger))
-yieldreturndir;
-if(Path.DirectorySeparatorChar!='\\')
-yieldbreak;
-foreach(vardirinAndroidSdkWindows.GetJdkInfos(logger)){
-yieldreturndir;
-}
-}
-
-staticIEnumerable<JdkInfo>GetMacOSMicrosoftOpenJdks(Action<TraceLevel,string>logger)
-{
-returnGetMacOSMicrosoftOpenJdkPaths()
-.Select(p =>TryGetJdkInfo(p,logger,"/Library/Java/JavaVirtualMachines/microsoft-*.jdk"))
-.Where(jdk =>jdk!=null)
-.Select(jdk =>jdk!)
-.OrderByDescending(jdk =>jdk,JdkInfoVersionComparer.Default);
-}
-
-staticIEnumerable<string>GetMacOSMicrosoftOpenJdkPaths()
-{
-varroot="/Library/Java/JavaVirtualMachines";
-varpattern="microsoft-*.jdk";
-vartoHome=Path.Combine("Contents","Home");
-varjdks=AppDomain.CurrentDomain.GetData($"GetMacOSMicrosoftJdkPaths jdks override! {typeof(JdkInfo).AssemblyQualifiedName}")
-?.ToString();
-if(jdks!=null){
-root=jdks;
-toHome="";
-pattern="*";
-}
-if(!Directory.Exists(root)){
-yieldbreak;
-}
-foreach(vardirinDirectory.EnumerateDirectories(root,pattern)){
-varhome=Path.Combine(dir,toHome);
-if(!Directory.Exists(home))
-continue;
-yieldreturnhome;
-}
-}
-
-staticJdkInfo?TryGetJdkInfo(stringpath,Action<TraceLevel,string>logger,stringlocator)
+internalstaticJdkInfo?TryGetJdkInfo(stringpath,Action<TraceLevel,string>logger,stringlocator)
 {
 JdkInfo?jdk=null;
 try{
@@ -369,13 +311,6 @@ static IEnumerable<string> GetMacOSMicrosoftOpenJdkPaths ()
 returnjdk;
 }
 
-staticIEnumerable<JdkInfo>GetWindowsJdks(Action<TraceLevel,string>logger)
-{
-if(!OS.IsWindows)
-returnEnumerable.Empty<JdkInfo>();
-returnAndroidSdkWindows.GetJdkInfos(logger);
-}
-
 staticIEnumerable<JdkInfo>GetEnvironmentVariableJdks(stringenvVar,Action<TraceLevel,string>logger)
 {
 varjava_home=Environment.GetEnvironmentVariable(envVar);

src/Xamarin.Android.Tools.AndroidSdk/Jdks/AzulJdkLocations.cs

@@ -0,0 +1,20 @@
+usingSystem;
+usingSystem.Collections.Generic;
+usingSystem.Diagnostics;
+usingSystem.IO;
+usingSystem.Linq;
+usingSystem.Text;
+
+namespaceXamarin.Android.Tools{
+
+classAzulJdkLocations:JdkLocations{
+
+internalstaticIEnumerable<JdkInfo>GetAzulJdks(Action<TraceLevel,string>logger)
+{
+returnGetMacOSSystemJdks("zulu-*.jdk",logger)
+.Concat(GetWindowsFileSystemJdks(Path.Combine("Zulu","zulu-*"),logger))
+.Concat(GetWindowsRegistryJdks(logger,@"SOFTWARE\Azul Systems\Zulu","zulu-*",null,"InstallationPath"))
+.OrderByDescending(jdk =>jdk,JdkInfoVersionComparer.Default);
+}
+}
+}

src/Xamarin.Android.Tools.AndroidSdk/Jdks/JdkLocations.MacOS.cs

@@ -0,0 +1,62 @@
+usingSystem;
+usingSystem.Collections.Generic;
+usingSystem.Diagnostics;
+usingSystem.IO;
+usingSystem.Linq;
+
+namespaceXamarin.Android.Tools{
+
+partialclassJdkLocations{
+
+staticIEnumerable<JdkInfo>GetUnixPreferredJdks(Action<TraceLevel,string>logger)
+{
+returnGetUnixConfiguredJdkPaths(logger)
+.Select(p =>JdkInfo.TryGetJdkInfo(p,logger,"monodroid-config.xml"))
+.Where(jdk =>jdk!=null)
+.Select(jdk =>jdk!)
+.OrderByDescending(jdk =>jdk,JdkInfoVersionComparer.Default);
+}
+
+staticIEnumerable<string>GetUnixConfiguredJdkPaths(Action<TraceLevel,string>logger)
+{
+varconfig=AndroidSdkUnix.GetUnixConfigFile(logger);
+foreach(varjava_sdkinconfig.Root.Elements("java-sdk")){
+varpath=(string)java_sdk.Attribute("path");
+yieldreturnpath;
+}
+}
+
+conststringMacOSJavaVirtualMachinesRoot="/Library/Java/JavaVirtualMachines";
+
+protectedstaticIEnumerable<JdkInfo>GetMacOSSystemJdks(stringpattern,Action<TraceLevel,string>logger,string?locator=null)
+{
+if(!OS.IsMac){
+returnArray.Empty<JdkInfo>();
+}
+locator=locator??Path.Combine(MacOSJavaVirtualMachinesRoot,pattern);
+returnFromPaths(GetMacOSSystemJvmPaths(pattern),logger,locator);
+}
+
+staticIEnumerable<string>GetMacOSSystemJvmPaths(stringpattern)
+{
+varroot=MacOSJavaVirtualMachinesRoot;
+vartoHome=Path.Combine("Contents","Home");
+varjdks=AppDomain.CurrentDomain.GetData($"GetMacOSMicrosoftJdkPaths jdks override! {typeof(JdkInfo).AssemblyQualifiedName}")
+?.ToString();
+if(jdks!=null){
+root=jdks;
+toHome="";
+pattern="*";
+}
+if(!Directory.Exists(root)){
+yieldbreak;
+}
+foreach(vardirinDirectory.EnumerateDirectories(root,pattern)){
+varhome=Path.Combine(dir,toHome);
+if(!Directory.Exists(home))
+continue;
+yieldreturnhome;
+}
+}
+}
+}

src/Xamarin.Android.Tools.AndroidSdk/Jdks/JdkLocations.Windows.cs

@@ -0,0 +1,113 @@
+usingSystem;
+usingSystem.Collections.Generic;
+usingSystem.Diagnostics;
+usingSystem.IO;
+usingSystem.Linq;
+usingSystem.Text;
+usingSystem.Text.RegularExpressions;
+
+namespaceXamarin.Android.Tools{
+
+partialclassJdkLocations{
+
+internalstaticstring?GetWindowsPreferredJdkPath()
+{
+varwow=RegistryEx.Wow64.Key32;
+varregKey=AndroidSdkWindows.GetMDRegistryKey();
+if(RegistryEx.CheckRegistryKeyForExecutable(RegistryEx.CurrentUser,regKey,AndroidSdkWindows.MDREG_JAVA_SDK,wow,"bin","java.exe"))
+returnRegistryEx.GetValueString(RegistryEx.CurrentUser,regKey,AndroidSdkWindows.MDREG_JAVA_SDK,wow);
+returnnull;
+
+}
+
+protectedstaticIEnumerable<JdkInfo>GetWindowsFileSystemJdks(stringpattern,Action<TraceLevel,string>logger,string?locator=null)
+{
+if(!OS.IsWindows){
+yieldbreak;
+}
+
+varroots=newList<string>(){
+// "Compatibility" with existing codebases; should probably be avoided…
+Environment.ExpandEnvironmentVariables("%ProgramW6432%"),
+Environment.GetFolderPath(Environment.SpecialFolder.ProgramFiles),
+Environment.GetFolderPath(Environment.SpecialFolder.ProgramFilesX86),
+};
+foreach(varrootinroots){
+if(!Directory.Exists(root))
+continue;
+IEnumerable<string>homes;
+try{
+homes=Directory.EnumerateDirectories(root,pattern);
+}
+catch(IOExceptione){
+continue;
+}
+foreach(varhomeinhomes){
+if(!File.Exists(Path.Combine(home,"bin","java.exe")))
+continue;
+varloc=locator??$"{pattern} via {root}";
+varjdk=JdkInfo.TryGetJdkInfo(home,logger,loc);
+if(jdk==null)
+continue;
+yieldreturnjdk;
+}
+}
+}
+
+protectedstaticIEnumerable<JdkInfo>GetWindowsRegistryJdks(
+Action<TraceLevel,string>logger,
+stringparentKey,
+stringchildKeyGlob,
+string?grandChildKey,
+stringvalueName,
+string?locator=null)
+{
+if(!OS.IsWindows){
+yieldbreak;
+}
+
+varregex=ToRegex(childKeyGlob);
+varpaths=newList<(Versionversion,stringpath)>();
+varroots=new[]{RegistryEx.CurrentUser,RegistryEx.LocalMachine};
+varwows=new[]{RegistryEx.Wow64.Key32,RegistryEx.Wow64.Key64};
+foreach(varrootinroots)
+foreach(varwowinwows){
+foreach(varsubkeyNameinRegistryEx.EnumerateSubkeys(root,parentKey,wow)){
+if(!regex.Match(subkeyName).Success){
+continue;
+}
+varkey=$@"{parentKey}\{subkeyName}"+
+(grandChildKey==null?"":"\\"+grandChildKey);
+varpath=RegistryEx.GetValueString(root,key,valueName,wow);
+if(path==null){
+continue;
+}
+varjdk=JdkInfo.TryGetJdkInfo(path,logger,locator??$"Windows Registry @ {parentKey}");
+if(jdk==null){
+continue;
+}
+yieldreturnjdk;
+}
+}
+}
+
+staticRegexToRegex(stringglob)
+{
+varr=newStringBuilder();
+foreach(charcinglob){
+switch(c){
+case'*':
+r.Append(".*");
+break;
+case'?':
+r.Append(".");
+break;
+default:
+r.Append(Regex.Escape(c.ToString()));
+break;
+}
+}
+returnnewRegex(r.ToString(),RegexOptions.CultureInvariant|RegexOptions.IgnoreCase);
+}
+}
+}

src/Xamarin.Android.Tools.AndroidSdk/Jdks/JdkLocations.cs

@@ -0,0 +1,32 @@
+usingSystem;
+usingSystem.Collections.Generic;
+usingSystem.Diagnostics;
+usingSystem.IO;
+usingSystem.Linq;
+
+namespaceXamarin.Android.Tools{
+
+partialclassJdkLocations{
+
+internalstaticIEnumerable<JdkInfo>GetPreferredJdks(Action<TraceLevel,string>logger)
+{
+if(OS.IsWindows){
+varpath=GetWindowsPreferredJdkPath();
+varjdk=path==null?null:JdkInfo.TryGetJdkInfo(path,logger,"Windows Registry");
+if(jdk!=null)
+yieldreturnjdk;
+}
+foreach(varjdkinGetUnixPreferredJdks(logger)){
+yieldreturnjdk;
+}
+}
+
+protectedstaticIEnumerable<JdkInfo>FromPaths(IEnumerable<string>paths,Action<TraceLevel,string>logger,stringlocator)
+{
+returnpaths
+.Select(p =>JdkInfo.TryGetJdkInfo(p,logger,locator))
+.Where(jdk =>jdk!=null)
+.Select(jdk =>jdk!);
+}
+}
+}

src/Xamarin.Android.Tools.AndroidSdk/Jdks/MicrosoftOpenJdkLocations.cs

@@ -0,0 +1,20 @@
+usingSystem;
+usingSystem.Collections.Generic;
+usingSystem.Diagnostics;
+usingSystem.IO;
+usingSystem.Linq;
+usingSystem.Text;
+
+namespaceXamarin.Android.Tools{
+
+classMicrosoftOpenJdkLocations:JdkLocations{
+
+internalstaticIEnumerable<JdkInfo>GetMicrosoftOpenJdks(Action<TraceLevel,string>logger)
+{
+returnGetMacOSSystemJdks("microsoft-*.jdk",logger)
+.Concat(GetWindowsFileSystemJdks(Path.Combine("Microsoft","jdk-*"),logger))
+.Concat(GetWindowsRegistryJdks(logger,@"SOFTWARE\Microsoft\JDK","*",@"hotspot\MSI","Path"))
+.OrderByDescending(jdk =>jdk,JdkInfoVersionComparer.Default);
+}
+}
+}