getNextFileName: Get info wether filename is a file or directory

[tueddy]

Hi Arduino-ESP32 team,

the FS function getNextFilename() has been merged since 2.0.6 and speeds-up directory listing by factor >20 (many files on SD-card).
Thank's for this improvement!

Unfortunately, this function can only be used to a limited extent because it is not possible to distinguish whether the returned name is a file or a directory. This may have been overlooked in PR #7229 , see discussion.
A concrete use case is an SD card web server that delivers a JSON file/directory structure for given path.

I have overloaded the function with a new return parameter isDir. This returns true if it is a directory:

    String getNextFileName(void);
    String getNextFileName(boolean *isDir);

Changes are minimal & this PR should be fully backwards compatible.

Thank's
Dirk

Directory listing in the browser with openNextFile(). Loading one directory-level takes 2s:

Directory listing in the browser with getNextFileName(boolean *isDir). Loading one directory-level takes 20ms:

[CLAassistant]

Thank you for your submission! We really appreciate it. Like many open source projects, we ask that you sign our Contributor License Agreement before we can accept your contribution.

---

tueddy seems not to be a GitHub user. You need a GitHub account to be able to sign the CLA. If you have already a GitHub account, please add the email address used for this commit to your account.
_{You have signed the CLA already but the status is still pending? Let us recheck it.}

[P-R-O-C-H-Y]

Looks great! Thanks for contribution @tueddy :)
Please submit the CLA to be able to merge this.

[tueddy]

@P-R-O-C-H-Y Thank's for approving!
I had problems signing the CLA beacause my email was missing in first commit.
I have commited a small enhancement, checking for isDir != NULL to avoid a crash.
With this commit i hope the CLA signing was successful now..

[P-R-O-C-H-Y]

That check is good for sure. Can you just remove the spaces before the part so its aligned with other code?

[P-R-O-C-H-Y]

@tueddy Seems that CLA is still not signed yet.

[tueddy]

Don't know what's wrong with signing:

[P-R-O-C-H-Y]

Seems that the first commit doesn't know your GITHUB, and that's why this is happening..

[fschrempf]

Don't know what's wrong with signing:

I suspect it's because the first of your three commits still has the wrong author/e-mail. You should probably squash the commits into one and fix the authorship.

[P-R-O-C-H-Y]

Don't know what's wrong with signing:

I suspect it's because the first of your three commits still has the wrong author/e-mail. You should probably squash the commits into one and fix the authorship.

That should help. You can do squash yourself on your branch so you will still be the author :)

[P-R-O-C-H-Y]

@tueddy If there is still a problem, it will be faster to close this PR, create new branch and copy the changes there. After that open new PR and ping me to comment and I will approve it ASAP :)

[tueddy]

I will close here & open a new PR..