Ensure no file handles remain open during in-place persist (closes #292).

[fgimian]

Hey there, here's the fix for persisting files using the in-place option on Windows. This will ensure that the file handle used for processing of the file will be released before persisting to disk from the temp directory.

See output below:

~\source\jaq on  avoid-open-handles-during-persist [?] via 🦀 v1.88.0 took 3s
🕙 [ 09:48:19 AM ] ❯ git co main
Switched to branch 'main'
Your branch is up to date with 'origin/main'.

~\source\jaq on  main [?] via 🦀 v1.88.0
🕙 [ 09:48:26 AM ] ❯ cp ..\firefox-settings\bookmarks.json .

~\source\jaq on  main [?] via 🦀 v1.88.0
🕙 [ 09:48:31 AM ] ❯ cargo run -- -i . bookmarks.json
   Compiling jaq v2.2.0 (C:\Users\Fots\source\jaq\jaq)
    Finished `dev` profile [unoptimized + debuginfo] target(s) in 2.30s
     Running `target\debug\jaq.exe -i . bookmarks.json`
Error: failed to persist temporary file: Access is denied. (os error 5)
error: process didn't exit successfully: `target\debug\jaq.exe -i . bookmarks.json` (exit code: 2)

~\source\jaq on  main [?] via 🦀 v1.88.0 took 4s
🕙 [ 09:48:38 AM ] ❯ git co avoid-open-handles-during-persist
Switched to branch 'avoid-open-handles-during-persist'
Your branch is up to date with 'origin/avoid-open-handles-during-persist'.

~\source\jaq on  avoid-open-handles-during-persist [?] via 🦀 v1.88.0
🕙 [ 09:48:40 AM ] ❯ cp ..\firefox-settings\bookmarks.json .

~\source\jaq on  avoid-open-handles-during-persist [?] via 🦀 v1.88.0
🕙 [ 09:48:43 AM ] ❯ cargo run -- -i . bookmarks.json
   Compiling jaq v2.2.0 (C:\Users\Fots\source\jaq\jaq)
    Finished `dev` profile [unoptimized + debuginfo] target(s) in 2.20s
     Running `target\debug\jaq.exe -i . bookmarks.json`

Unfortunately, this does lead to a tiny bit of repeated code, but I think this is somewhat unavoidable.

Cheers
Fotis

[01mf02]

Hi @fgimian, thanks for diagnosing this problem! I find the code repetition to be a bit problematic, though; wouldn't it suffice to run std::mem::drop(file); just before let perms = ...?

[fgimian]

Hi @fgimian, thanks for diagnosing this problem! I find the code repetition to be a bit problematic, though; wouldn't it suffice to run std::mem::drop(file); just before let perms = ...?

Good idea, I'll give it a try tomorrow and let you know how it goes.

Cheers
Fotis

[fgimian]

@01mf02 Thanks again for your help, I've tested your idea and it indeed does work as expected. I've updated the PR with the change discussed so it should be ready for review again.

Cheers
Fotis

[01mf02]

Excellent! Thanks for your confirmation and for your help with diagnosing this issue!