Media file upload

Checklist | 检查清单

Before marking this merge request as Ready, the following must be done:

在把这个合并请求标记成就绪之前，这些东西必须完成：

• The code must compile. Preferably, each commit should compile.

  代码必须能编译。最好每个提交都能编译。

• Any added UI text must be translated via l10n.get(). The messages must be translated into every core language: en, cmn.

  任何添加的 UI 文字都要用 l10n.get() 翻译。 讯息必须翻译成所有核心语言：en，cmn。

  • The merge request creator must translate each message into one of the core languages. The others can be handled by others.

    开合并请求的人必须把每条讯息翻译成一种核心语言。 别的可以给别人做。

• If the merge request contains a user-visible change, it must have a changelog.

  如果这个合并请求包括对用户可见的更改，必须写个更改记录。

TODO

• Set msgtype according to mimetype.

  根据mimetype设置msgtype。

• When an error is encountered, show the reason.

  简单的错误原因提示。

已知的问题 | Known issues

• Switching back and forth between rooms causes the upload list to appear blank.

  在房间间来回切换会导致上传列表显示空白。

• After starting the download, switching back and forth between rooms causes the program to crash

  开始下载任务后，在房间间来回切换会导致程序崩溃

Tested features | 已测试的功能

• Simple upload/download. Start the upload/download task and wait for the task to complete to check whether it is successful and whether the relevant UI is displayed normally.

  简单上传/下载。开启上传/下载任务，等待任务完成，查看是否成功及相关 UI 是否正常显示。

• Upload/download with switch room operation. After the upload/download task is started, switch rooms, and the upload/download task should run normally in the background. After switching back to the room, the progress of the incomplete upload/download task should be updated in real time, and the completed task leaves a message representing the result at the location where the upload/download was started (no information if the upload is successful).

  带有切换房间操作的上传/下载。开启上传/下载任务后切换房间，上传/下载任务应在后台正常进行。切换回该房间后，未完成的上传/下载任务的进度应实时更新，已完成的任务在发起上传/下载的位置留下表征结果的信息（上传成功则无信息）。

• The UI is scalable depends on the size of the window (text should wrap automatically, and progress bars should be variable in length).

  UI 能够跟随应用尺寸伸缩（文字应做到自动折行，进度条应做到长度可变）。

• Error handling.Cancel the task when an error occurs and display a message where the task is started. Supported error messages are:

  错误处理。发生错误时取消任务并在开启任务的地方显示消息。已支持的错误信息有：

  • User canceled

    用户手动取消

  • Open file error.For example, an attempt was made to save a file to a file that exceeded permissions

    打开文件错误。例如试图将文件保存到一个超出用户权限的文件。

  • Write file error.

    写文件错误。

  • Internal error.It always a bug.

    内部错误，通常是一个 bug 。