title: VS Code extension - get full path
body: <p>I am writing a plugin for VS Code and I need to know the path of the file which is calling the extension, either if it was called from the editor context menu or explorer context menu or the user simply typed the extension command.</p>
  
  <pre><code>function activate(context){
      // get full path of the file somehow
  }
  </code></pre>
  
  <p>Thanks in advance!</p>