Research: Drag and Drop from Finder

Overview

Mac does not provide a set of simple APIs to handle dropping files from Finder. So we need to find a solution either by updating CEF and/or implementing our own handling of drag-and-drop events. We need to handle at least two main events.

• OnDragEnter event -- need this event to get the file paths of all the dragged files and folders.
• OnDrop -- need this event to open all the dropped files.

Findings

• We need CefDragHandler introduced in CEF version 3.1453.1279 so that we can get the file paths of the dragged files and folders.
• We can use onDrop event in JavaScript to trigger the opening of the dropped files.
• Although we already have native shell implementation of drag-and-drop from Windows Explorer, it is also preventing us from enabling drag-and-drop in CodeMirror (ie. dragging text within the document). By switching to onDrop event in JavaScript we can also enable drag-and-drop of text inside a document.