1160109 - Handling OSFile errors is unnecessarily complex due to different error types across platforms

Status: RESOLVED WORKSFORME

(Toolkit Graveyard :: OS.File, defect)

Description

[Mark Banner (:standard8)]

OSFile's error handling causes really complex code. For some code I'm writing in Loop, I need to attempt to read a file, and then only log an error if the error is not "file not found".

Currently OSFile gives a custom error, and its different across platforms, so I have to do:

if ((OS.Constants.libc && error.unixErrno != OS.Constants.libc.ENOENT) ||
    (OS.Constants.Win && error.winLastError != OS.Constants.Win.ERROR_FILE_NOT_FOUND)) {
  ...etc

Really this should be something like:

if (error.errno == Cr.NS_ERROR_FILE_NOT_FOUND) {

which would be much simpler and less prone to errors.

Comment 1

[David Teller [:Yoric] - still alive but not very active]

Actually, XPCOM errors are very bad at matching file errors. In many cases, there is no XPCOM error for a given file error, and in some cases there are several. However, OS.File defines a number of `becauseXXX` helpers to help with this purpose:

Here, your code should look like

`if (error.becauseNoSuchFile) {
}`

Which I believe is even better than what you request. If you find missing `becauseXXX` getters, don't hesitate to file bugs.

Comment 2

[David Teller [:Yoric] - still alive but not very active]

In the absence of response, I'm WONTFIXing this. Please reopen if you feel I have missed something.