VS: Extract instance version from VS Installer

Source/cmGlobalVisualStudioVersionedGenerator.cxx

@@ -366,6 +366,12 @@ bool cmGlobalVisualStudioVersionedGenerator::GetVSInstance(
   return vsSetupAPIHelper.GetVSInstanceInfo(dir);
 }
 
+bool cmGlobalVisualStudioVersionedGenerator::GetVSInstanceVersion(
+  unsigned long long& vsInstanceVersion) const
+{
+  return vsSetupAPIHelper.GetVSInstanceVersion(vsInstanceVersion);
+}
+
 bool cmGlobalVisualStudioVersionedGenerator::IsDefaultToolset(
   const std::string& version) const
 {

Source/cmGlobalVisualStudioVersionedGenerator.h

@@ -29,6 +29,8 @@ public:
 
   bool GetVSInstance(std::string& dir) const;
 
+  bool GetVSInstanceVersion(unsigned long long& vsInstanceVersion) const;
+
   bool IsDefaultToolset(const std::string& version) const override;
   std::string GetAuxiliaryToolset() const override;
 

Source/cmVSSetupHelper.cxx

@@ -258,6 +258,20 @@ bool cmVSSetupAPIHelper::GetVSInstanceInfo(std::string& vsInstallLocation)
   return isInstalled;
 }
 
+bool cmVSSetupAPIHelper::GetVSInstanceVersion(
+  unsigned long long& vsInstanceVersion)
+{
+  vsInstanceVersion = 0;
+  bool isInstalled = this->EnumerateAndChooseVSInstance();
+
+  if (isInstalled) {
+    vsInstanceVersion =
+      static_cast<unsigned long long>(chosenInstanceInfo.ullVersion);
+  }
+
+  return isInstalled;
+}
+
 bool cmVSSetupAPIHelper::GetVCToolsetVersion(std::string& vsToolsetVersion)
 {
   vsToolsetVersion.clear();

Source/cmVSSetupHelper.h

@@ -106,6 +106,7 @@ public:
 
   bool IsVSInstalled();
   bool GetVSInstanceInfo(std::string& vsInstallLocation);
+  bool GetVSInstanceVersion(unsigned long long& vsInstanceVersion);
   bool GetVCToolsetVersion(std::string& vsToolsetVersion);
   bool IsWin10SDKInstalled();
   bool IsWin81SDKInstalled();