Implement virtualenv detection for Windows. Refactoring along the way.

Fixes #69

Author: segevfiner

lib/main.js

@@ -7,6 +7,9 @@ const { Directory } = require("atom");
 // adapted from http://stackoverflow.com/q/5474008
 const PYTHON_REGEX = /(([^\d\W]|[\u00A0-\uFFFF])[\w.\u00A0-\uFFFF]*)|\.$/;
 
+const VIRTUAL_ENV_BIN_DIRS = ["bin", "Scripts"];
+const VIRTUAL_ENV_EXECUTABLES = ["python", "python.exe"];
+
 class PythonLanguageClient extends AutoLanguageClient {
   getGrammarScopes() {
     return ["source.python"];
@@ -28,11 +31,9 @@ class PythonLanguageClient extends AutoLanguageClient {
     return { pyls: { plugins: configuration } }
   }
 
-  async startServerProcess(projectPath) {
-    await new Promise(resolve => atom.whenShellEnvironmentLoaded(resolve));
-
+  async detectVirtualEnv(path) {
     const entries = await new Promise(resolve =>
-      new Directory(projectPath).getEntries((error, entries) => {
+      new Directory(path).getEntries((error, entries) => {
         if (error === null) {
           resolve(entries);
         } else {
@@ -41,31 +42,38 @@ class PythonLanguageClient extends AutoLanguageClient {
       })
     );
 
-    let venvPath = null;
-
     if (entries) {
       for (let entry of entries) {
         if (entry.isDirectory()) {
-          if (
-            entry.getBaseName() === "bin" &&
-            (await entry.getFile("python").exists())
-          ) {
-            venvPath = projectPath;
-            break;
+          if (VIRTUAL_ENV_BIN_DIRS.indexOf(entry.getBaseName()) !== -1) {
+            for (let executable of VIRTUAL_ENV_EXECUTABLES) {
+              if (await entry.getFile(executable).exists()) {
+                return path;
+              }
+            }
           } else {
-            if (
-              await entry
-                .getSubdirectory("bin")
-                .getFile("python")
-                .exists()
-            ) {
-              venvPath = entry.getPath();
-              break;
+            for (let dir_name of VIRTUAL_ENV_BIN_DIRS) {
+              for (let executable of VIRTUAL_ENV_EXECUTABLES) {
+                if (
+                  await entry
+                    .getSubdirectory(dir_name)
+                    .getFile(executable)
+                    .exists()
+                ) {
+                  return entry.getPath();
+                }
+              }
             }
           }
         }
       }
     }
+  }
+
+  async startServerProcess(projectPath) {
+    await new Promise(resolve => atom.whenShellEnvironmentLoaded(resolve));
+
+    let venvPath = await this.detectVirtualEnv(projectPath)
 
     const pylsEnvironment = Object.assign({}, process.env);