Add args options to VS code tasks

Closes eng/ide/ada_language_server#1113

Author: reznikmm

README.md

@@ -174,6 +174,28 @@ You can bind keyboard shortcuts to them by adding to the `keybindings.json` file
 
 [A demo for auto-detected tasks](https://github.com/AdaCore/ada_language_server/wiki/auto_detected_tasks.mp4)
 
+#### Task customization
+You can [customize autodetected tasks](https://code.visualstudio.com/docs/editor/tasks#_customizing-autodetected-tasks)
+by providing extra tool command line options via `args` property in the `tasks.json`:
+
+```json
+{
+	"version": "2.0.0",
+	"tasks": [
+		{
+			"type": "gnat",
+			"taskKind": "buildProject",
+			"problemMatcher": [
+				"$ada"
+			],
+			"group": "build",
+			"label": "ada: Build project",
+			"args": ["-gargs", "-vh"]
+		}
+	]
+}
+```
+
 ### Commands and shortcuts
 
 The extension contributes a few commands and corresponding key bindings.

integration/vscode/Code Samples/hello/.vscode/tasks.json

@@ -4,21 +4,14 @@
     "version": "2.0.0",
     "tasks": [
         {
-            "label": "build",
-            "type": "shell",
-            "command": "gprbuild",
-            "args": [
-                "-p",
-                "-P",
-                "${config:ada.projectFile}",
-                "-cargs",
-                "-gnatef"
+            "type": "gnat",
+            "taskKind": "buildProject",
+            "problemMatcher": [
+                "$ada"
             ],
-            "problemMatcher": ["$ada"],
-            "group": {
-                "kind": "build",
-                "isDefault": true
-            }
+            "group": "build",
+            "label": "ada: Build project",
+            "args": ["-gargs", "-q"]
         }
     ]
 }

integration/vscode/ada/package.json

@@ -379,6 +379,10 @@
                     "taskKind": {
                         "type": "string",
                         "description": "Tool and action kind"
+                    },
+                    "args": {
+                        "type": "array",
+                        "description": "Extra command arguments"
                     }
                 }
             }

integration/vscode/ada/src/gnatTaskProvider.ts

@@ -190,11 +190,14 @@ export default class GnatTaskProvider implements vscode.TaskProvider<vscode.Task
         // Check if the task in our known task
         if (definition.taskKind in knownTaskKinds) {
             const item: TaskProperties = knownTaskKinds[String(definition.taskKind)];
+            const extraArgs: string[] = Array.isArray(definition.args)
+                ? definition.args.map((x) => String(x))
+                : [];
             if (item.extra) {
                 // We have a callback, evaluate it to get an extra argument and
                 // wrap all args with getGnatArgs
                 return item.extra().then((extra) => {
-                    const args = getGnatArgs(item.args.concat(extra ? [extra] : []));
+                    const args = getGnatArgs(item.args.concat(extraArgs, extra ? [extra] : []));
                     const shell = new vscode.ShellExecution(item.tool, args);
                     return new vscode.Task(
                         definition,
@@ -206,7 +209,7 @@ export default class GnatTaskProvider implements vscode.TaskProvider<vscode.Task
                     );
                 });
             } else {
-                const shell = new vscode.ShellExecution(item.tool, item.args);
+                const shell = new vscode.ShellExecution(item.tool, item.args.concat(extraArgs));
                 return new vscode.Task(
                     definition,
                     vscode.TaskScope.Workspace, // scope