File Loop app example

[Ophirr33]

This is a rough draft of the file loop example. I'd love some feedback on how to make it more concise. Right now there's a lot of boiler plate on iterating through the file system, and check parent paths. Though, the file system boilerplate could help make a better case for walkdir. @budziq , thanks for the tip on how to make a sym link loop. Fixes #207

[budziq]

Hi @Ophirr33 Thanks for the PR.

As you've discovered you are reimplementing part of walkdir I would suggest to avoid that 😄.

Here are some thoughts:
The original idea was to take a Path:

• split it into elements and just check each pair without any calls to fs::read_dir or need for a HashMap.
• please note that PathBuf already acts as a stack implementing pop and push operations
• I wouldn't worry about performance optimization here. We want to show the general concept and the reader would be perfectly capable of implementing their own caching scheme - so please skip the HashMap

So with this simplified assumptions this could be made into a 4-5 liner.

Also could you:

• run rustfmt on the code after it's ready
• squash the commits into one
• rebase the PR to latest master

[budziq]

Hi @Ophirr33 Thanks for the PR.

As you've discovered you are reimplementing part of walkdir I would suggest to avoid that 😄.

Here are some thoughts:
The original idea was to take a Path:

• split it into elements and just check each pair without any calls to fs::read_dir or need for a HashMap.
• please note that PathBuf already acts as a stack implementing pop and push operations
• I wouldn't worry about performance optimization here. We want to show the general concept and the reader would be perfectly capable of implementing their own caching scheme - so please skip the HashMap

So with this simplified assumptions this could be made into a 4-5 liner.

Also could you:

• run rustfmt on the code after it's ready
• squash the commits into one
• rebase the PR to latest master

[budziq]

no need to explicitly mention the std::path module.

[Ophirr33]

Hey @budziq, thanks for the feedback, I definitely misread what the example was going for.

[budziq]

Yeah lesson for me to be more explicit with descriptions.
Great work.

[budziq]

Yeah lesson for me to be more explicit with descriptions.
Great work.

[budziq]

• the contains_loop tests only if the whole path is pointing to one of its ancestors while we would like to find all loops. calling it repeatedly on poped path segments will do the trick
• How about returning the result with optional looped path segments? (this might not come out that clean so I'll leave it up to you)

[Ophirr33]

Not 100% sure if I'm following. Basically it should detect a loop even when you don't specify the looped directory, right?

[budziq]

we may use AsRef here as well to make it usable with &str

[Ophirr33]

@budziq It checks all paths and will return what paths it's looping between now. Let me know what else I can do

[budziq]

Excellent. One more tiny detail and we are good to merge

[budziq]

Excellent. One more tiny detail and we are good to merge

[budziq]

Please change the link same-file::is_same_file to same_file::is_same_file

[Ophirr33]

@budziq Done!

[budziq]

@Ophirr33 Well done!