[Xamarin.Android.Tools.AndroidSdk] JdkInfo + JDK11 + Windows (#88)

Context: dotnet/android#4567
Commit 36d7fee added support for JetBrains OpenJDK 11 detection on
macOS and Linux.
Lacking was *Windows* support for JetBrains OpenJDK 11, because of
course it has to be different.
In particular, OpenJDK 11 *moves the `jvm` library* for Windows.
We checked for it in `{HomePath}\jre\**\jvm.dll` or
`{HomePath}\lib\**\jvm.dll`, but neither of those exist. Instead,
OpenJDK 11 has `jvm.dll` in `{HomePath}\bin\server\jvm.dll`, which is
also the only `.dll` file in the `.tar.gz` which exports the symbol
`JNI_CreateJavaVM`.
Update `JdkInfo` so that it looks for `{HomePath}\bin\server\jvm.dll`
to populate `JdkInfo.JdkJvmPath`.

Author: jonpryor

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

@@ -14,10 +14,6 @@
 namespaceXamarin.Android.Tools
 {
 publicclassJdkInfo{
-staticreadonlystring[]JdkLibraryTopDirs={
-"jre",
-"lib",
-};
 
 publicstringHomePath{get;}
 
@@ -58,27 +54,14 @@ public JdkInfo (string homePath)
 JavaPath=ProcessUtils.FindExecutablesInDirectory(binPath,"java").FirstOrDefault();
 JavacPath=ProcessUtils.FindExecutablesInDirectory(binPath,"javac").FirstOrDefault();
 
-string?topDir=null;
-foreach(stringdirinJdkLibraryTopDirs){
-topDir=Path.Combine(HomePath,dir);
-if(!Directory.Exists(topDir)){
-topDir=null;
-continue;
-}
-break;
-}
-
-if(String.IsNullOrEmpty(topDir))
-topDir=Path.Combine(HomePath,JdkLibraryTopDirs[0]);
-
-JdkJvmPath=OS.IsMac
-?FindLibrariesInDirectory(topDir!,"jli").FirstOrDefault()
-:FindLibrariesInDirectory(topDir!,"jvm").FirstOrDefault();
+string?jdkJvmPath=GetJdkJvmPath();
 
 ValidateFile("jar",JarPath);
 ValidateFile("java",JavaPath);
 ValidateFile("javac",JavacPath);
-ValidateFile("jvm",JdkJvmPath);
+ValidateFile("jvm",jdkJvmPath);
+
+JdkJvmPath=jdkJvmPath!;
 
 varincludes=newList<string>();
 varjdkInclude=Path.Combine(HomePath,"include");
@@ -132,6 +115,24 @@ public bool GetJavaSettingsPropertyValue (string key, [NotNullWhen (true)] out s
 returnfalse;
 }
 
+string?GetJdkJvmPath()
+{
+stringjreDir=Path.Combine(HomePath,"jre");
+stringlibDir=Path.Combine(HomePath,"lib");
+
+if(OS.IsMac){
+returnFindLibrariesInDirectory(jreDir,"jli").FirstOrDefault()??
+FindLibrariesInDirectory(libDir,"jli").FirstOrDefault();
+}
+if(OS.IsWindows){
+stringbinServerDir=Path.Combine(HomePath,"bin","server");
+returnFindLibrariesInDirectory(jreDir,"jvm").FirstOrDefault()??
+FindLibrariesInDirectory(binServerDir,"jvm").FirstOrDefault();
+}
+returnFindLibrariesInDirectory(jreDir,"jvm").FirstOrDefault()??
+FindLibrariesInDirectory(libDir,"jvm").FirstOrDefault();
+}
+
 staticIEnumerable<string>FindLibrariesInDirectory(stringdir,stringlibraryName)
 {
 if(!Directory.Exists(dir))
@@ -140,7 +141,7 @@ static IEnumerable<string> FindLibrariesInDirectory (string dir, string libraryN
 returnDirectory.EnumerateFiles(dir,library,SearchOption.AllDirectories);
 }
 
-voidValidateFile(stringname,stringpath)
+voidValidateFile(stringname,string?path)
 {
 if(path==null||!File.Exists(path))
 thrownewArgumentException($"Could not find required file `{name}` within `{HomePath}`; is this a valid JDK?","homePath");