V119-052: pass custom env variables to the ALS

Use the already existing VS Code preferences to control
the environment variables and pass them to all the child
processes launched by the extension, including the ALS.

This allows to set a custom PATH or GPR_PROJECT_PATH in a
workspace file for a given project for instance, or control
the scenario variables directly from the environment.

Author: AnthonyLeonardoGracio

integration/vscode/ada/src/extension.ts

@@ -22,7 +22,9 @@ import {
     LanguageClientOptions,
     Middleware,
     ServerOptions,
+    ExecutableOptions
 } from 'vscode-languageclient/node';
+import { platform } from 'os';
 import * as process from 'process';
 import GPRTaskProvider from './gprTaskProvider';
 import cleanTaskProvider from './cleanTaskProvider';
@@ -91,10 +93,34 @@ export function activate(context: vscode.ExtensionContext): void {
         // let debugOptions = { execArgv: [] };
         // If the extension is launched in debug mode then the debug server options are used
         // Otherwise the run options are used
+
+        // Retrieve the user's custom environment variables if specified in their
+        // settings/workspace: we'll then launch any child process with this custom
+        // environment
+        var user_platform = platform();
+        var env_config_name: string = "terminal.integrated.env.linux";
+
+        switch (user_platform) {
+            case 'darwin': env_config_name = "terminal.integrated.env.osx"
+                break;
+            case 'win32': env_config_name = "terminal.integrated.env.windows";
+                break;
+            default: env_config_name = "terminal.integrated.env.linux";
+        }
+
+        const custom_env = vscode.workspace.getConfiguration().get(
+            env_config_name) ?? Object.create(null)
+
+        for (let var_name in custom_env) {
+            process.env[var_name] = custom_env[var_name];
+        }
+
+        // Options to control the server
         const serverOptions: ServerOptions = {
             run: { command: serverModule, args: extra },
-            debug: { command: serverModule, args: extra },
+            debug: { command: serverModule, args: extra }
         };
+
         // Options to control the language client
         const clientOptions: LanguageClientOptions = {
             // Register the server for ada sources documents