Add 'Terminate Task' command

Fixes #5159

Added a new command `Terminate Task` which prompts users to select
a running task if available in order to terminate it.

Signed-off-by: Vincent Fugnitto <vincent.fugnitto@ericsson.com>

packages/task/src/browser/task-frontend-contribution.ts

@@ -27,7 +27,8 @@ import { TaskContribution, TaskResolverRegistry, TaskProviderRegistry } from './
 import { TaskService } from './task-service';
 import { TerminalMenus } from '@theia/terminal/lib/browser/terminal-frontend-contribution';
 import { TaskSchemaUpdater } from './task-schema-updater';
-import { TaskConfiguration } from '../common';
+import { TaskConfiguration, TaskInfo } from '../common';
+import { QuickPickItem, QuickPickService } from '@theia/core/lib/common/quick-pick-service';
 
 export namespace TaskCommands {
     const TASK_CATEGORY = 'Task';
@@ -66,6 +67,12 @@ export namespace TaskCommands {
         category: TASK_CATEGORY,
         label: 'Clear History'
     };
+
+    export const TASK_TERMINATE: Command = {
+        id: 'task.terminate',
+        category: TASK_CATEGORY,
+        label: 'Terminate Task'
+    };
 }
 
 const TASKS_STORAGE_KEY = 'tasks';
@@ -102,6 +109,9 @@ export class TaskFrontendContribution implements CommandContribution, MenuContri
     @inject(StorageService)
     protected readonly storageService: StorageService;
 
+    @inject(QuickPickService)
+    protected readonly quickPickService: QuickPickService;
+
     onStart(): void {
         this.contributionProvider.getContributions().forEach(contrib => {
             if (contrib.registerResolvers) {
@@ -172,6 +182,13 @@ export class TaskFrontendContribution implements CommandContribution, MenuContri
                 execute: () => this.taskService.clearRecentTasks()
             }
         );
+
+        registry.registerCommand(
+            TaskCommands.TASK_TERMINATE,
+            {
+                execute: () => this.terminateTask()
+            }
+        );
     }
 
     registerMenus(menus: MenuModelRegistry): void {
@@ -212,4 +229,31 @@ export class TaskFrontendContribution implements CommandContribution, MenuContri
         });
     }
 
+    /**
+     * Terminate a running task.
+     */
+    async terminateTask(): Promise<void> {
+        const task = await this.selectTask();
+        if (task) {
+            this.taskService.kill(task.taskId);
+        }
+    }
+
+    /**
+     * Prompt user to select a running task.
+     */
+    protected async selectTask(): Promise<TaskInfo | undefined> {
+        const runningTasks: TaskInfo[] = await this.taskService.getRunningTasks();
+        const items: QuickPickItem<TaskInfo>[] = [];
+        runningTasks.forEach(task => {
+            items.push({
+                label: task.config.label,
+                value: task,
+            });
+        });
+        return this.quickPickService.show(runningTasks.map(
+            ({ config }, index) => ({ label: config.label, value: runningTasks[index] })
+        ), { placeholder: 'Select task to terminate' });
+    }
+
 }