Add caching to obsidian-list-all-files function

[kdmsnr]

This PR adds a caching mechanism to the obsidian-list-all-files function to improve its performance. The function now only scans the Obsidian directory once and subsequently uses the stored result. A new function, obsidian-clear-cache, is introduced to manually clear the cache when necessary.

ref. #39

[licht1stein]

Hey, thanks for the PR! One question, do you update the cache when creating new notes?

[kdmsnr]

Hi, thank you for your review! Based on your feedback, I've now adjusted the code so that the cache is also cleared when a note is saved. This ensures that the cache will always be updated when changes are made to the notes. I have committed this change. Please take a look!

[licht1stein]

Great! There's another case of new file being created, when following a link to a yet non existent file using obsidian-find-file, probably we should cover this case as well and invalidate cache if the file doesn't yet exist.

[licht1stein]

Does the hook that you add only work in obsidian-mode? Maybe instead of the hook we can just invalidate cache directly? The current way the hook will just stay there, wouldn't it?

[kdmsnr]

Based on your feedback, I've made adjustments to ensure the cache gets invalidated not only on note creation but also when following a link to a non-existent note etc.

I've also addressed the concern about the after-save-hook lingering by making it self-removing after it gets triggered once. This ensures that the cache is cleared only when a new note gets saved for the first time.

I've pushed these changes and updated the PR. Please take a look! I'm not fully versed in elisp, so I would really appreciate it if you could review this.

[kdmsnr]

Sorry for the confusion, I've reconsidered and understand now. This PR modifies obsidian-capture and obsidian-find-file to clear the cache before creating new files. This ensures that the cache is always up to date, without the need for hooks.

[licht1stein]

Great, thank you! I'll add a few final touches and bump the version :)

[licht1stein]

I broke down the logic into smaller pieces, please check that everything works :)