Use minimal powershell script to extract VS2017 location and version via COM*

Work with all flavors of VS2017, even the minimal "C++ Build Tools"
*https://blogs.msdn.microsoft.com/heaths/2016/09/15/changes-to-visual-studio-15-setup/

Author: refack

lib/find-vs2017.js

@@ -1,138 +1,74 @@
 module.exports = {
   locateMsbuild: locateMsbuild,
-  locateVS2017: locateVS2017,
-  getVS2017WinSDKVersion: getVS2017WinSDKVersion,
   setGypVS2017Env: setGypVS2017Env
 }
 
 var log = require('npmlog')
   , fs = require('fs')
   , path = require('path')
   , cp = require('child_process')
-  , win = process.platform == 'win32'
-  , msgFormat = require('util').format
-  , findPython = require('./find-python')
 
-var vs2017_install_path
-  , vs2017_win_sdk_ver
-
-function run_locate(gyp, callback) {
-  if (!win) {
-    return callback(null, '', '')
+var vs2017Setup
+
+function tryVS7_COM (gyp) {
+  if (vs2017Setup) return vs2017Setup;
+  try {
+    const csFile = path.join(__dirname, '..', 'tools', 'Get-VS7.cs');
+    const cmd = 'powershell -ExecutionPolicy Unrestricted -Command ' +
+      '"&{ Add-Type -Path \'' + csFile + '\'; [VisualStudioConfiguration.Main]::Query()}"'
+    const vsSetupRaw = cp.execSync(cmd).toString();
+    if (!vsSetupRaw) return;
+    const vsSetup = vsSetupRaw.split(/[\r|\n]/g).reduce((s, l) => {
+      const lParts = l.split(': ');
+      if (lParts.length > 1) s[lParts[0]] = lParts[1];
+      return s;
+    }, {});
+    return vs2017Setup = vsSetup;
+  } catch (e) {
+    gyp.log.verbose('try VS7', 'Couldn\'t find VS2017 :(');
   }
+}
 
-  if (vs2017_install_path || vs2017_install_path === '') {
-    return callback(null, vs2017_install_path, vs2017_win_sdk_ver)
-  } 
-
-  var python = gyp.opts.python || process.env.PYTHON || 'python2'
-    , findvc_path = path.join(__dirname, '..', 'find_vs2017.py')
-
-  findPython(python, locate_vc);    
-
-  function locate_vc(err, python_bin) {
-    if (err) {
-      return callback(err)
-    }
-
-    log.verbose('find vs2017', 'obtaining vs2017 install path using script %s',
-                findvc_path)
-    cp.execFile(python_bin, [findvc_path], function(err, stdout, stderr) {
-      if (err) {
-        return callback(err)
-      }
-      if (stdout) {
-        vs2017_install_path = stdout.split('\r\n')[0]
-        log.verbose('find vs2017', 'found Visual Studio 2017 in %s', vs2017_install_path)
-        get_sdk_version(python_bin)
-      } else {
-        log.verbose('find vs2017',
-                    'no valid Visual Studio 2017 installation found')
-        vs2017_install_path = ''
-        vs2017_win_sdk_ver = ''
-      }
-    })
+function tryVS7_registry(gyp) {
+  const magicKey = String.raw`HKLM\Software\Microsoft\VisualStudio\SxS\VS7`;
+  const magicQuery = `reg query ${magicKey} /reg:32`;
+  const qRet = cp.execSync(magicQuery).toString().trim();
+  if (qRet.includes('ERROR')) {
+    gyp.bindings.log('Couldn\'t find VS7 in registry:(');
+    return;
   }
-
-  function get_sdk_version(python_bin) {
-    log.verbose('find vs2017', 'obtaining installed Windows SDKs')
-    cp.execFile(python_bin, [findvc_path, vs2017_install_path],
-                function(err, stdout, stderr) {
-      if (err) {
-        return callback(err)
-      }              
-      if (stdout) {
-        vs2017_win_sdk_ver = stdout.split('\r\n')[0]
-        log.verbose('find vs2017', 'found VS2017 WinSDK %s', vs2017_win_sdk_ver)
-      } else {
-        log.verbose('find vs2017', 'no installed sdks found')
-      }
-
-      callback(null, vs2017_install_path, vs2017_win_sdk_ver)
-    })
+  const values = qRet.split(/[\r|\n]+/g).slice(1);
+  const ret = values.map(v => {
+    const parts = v.trim().replace(/\s+/g, ' ').split(' ');
+    return [Number(parts[0]), parts[2]];
+  });
+  if (!ret.length) {
+    gyp.bindings.log('Couldn\'t find VS7 in registry');
+    return;
   }
-
+  const maxVer = Math.max.apply(Math, ret.map(v => v[0]));
+  return ret.find(v => v[0] === maxVer)[1];
 }
 
 function locateMsbuild(gyp, callback) {
-  run_locate(gyp, function(err, vs_path, sdk) {
-    if (err) {
-      return callback(err)
-    }
-    if (vs_path === '') {
-      return callback()
-    }    
-    var msbuild_location = path.join(vs_path, 'MSBuild',
-                                     '15.0', 'Bin', 'MSBuild.exe')
-    log.verbose('find vs2017', 'looking for msbuild in %s', msbuild_location)
-    fs.access(msbuild_location, function(err) {
-      callback(null, err ? null : msbuild_location)
-    })
-  })
-}
+  const vsSetup = tryVS7_COM(gyp) || tryVS7_registry(gyp);
+  if (!vsSetup)return callback()
 
-function locateVS2017(gyp, callback) {
-  run_locate(gyp, function(err, vs_path, sdk) {
-    if (err) {
-      callback(err)
-    } else {
-      callback(null, vs_path === '' ? null : vs_path)
-    }
+  const msbuild_location = path.join(vsSetup.InstallationPath, 'MSBuild',
+                                     '15.0', 'Bin', 'MSBuild.exe')
+  log.verbose('find vs2017', 'looking for msbuild in %s', msbuild_location)
+  fs.access(msbuild_location, function(err) {
+    callback(null, err ? null : msbuild_location)
   })
 }
 
-function getVS2017WinSDKVersion(gyp, callback) {
-  run_locate(gyp, function(err, vs_path, sdk) {
-    if (err) {
-      callback(err)
-    } else {
-      callback(null, sdk === '' ? null : sdk)
-    }
-  })
-}
 
 function setGypVS2017Env(gyp, callback) {
-  locateVS2017(gyp, setPath)
-    
-  function setPath(err, vs_path) {
-    if (err) {
-      return callback(err)
-    }
-    if (vs_path) {
-      process.env['vs2017_install'] = vs_path
-      getVS2017WinSDKVersion(gyp, setSDK)
-    } else {
-      callback()
-    }
-  }
+  const vsSetup = tryVS7_COM(gyp) || tryVS7_registry(gyp);
+  if (!vsSetup)return callback()
 
-  function setSDK(err, sdk) {
-    if (err) {
-      return callback(err)
-    }
-    if (sdk) {
-      process.env['vs2017_sdk'] = sdk
-    }
-    callback()
-  }
+  gyp.opts.msvs_version = '2017';
+  process.env['vs2017_install'] = vsSetup.InstallationPath;
+  if (vsSetup.SDK) process.env['vs2017_sdk'] = vsSetup.SDK.replace(/\d+$/, '0')
+  callback();
 }