file path portability

Question

I have a program that I need to run under *nix and windows. because the program takes file paths from files the issue is what to do about the \ vs / issue.

My current thought is to put in a regex that converts the wrong one to the right one depending on what system I'm on. This will have the effect of letting either type work on either system. Aside from the fact that now I have two problems, does anyone see any other problems?

(Other better solutions are more than welcome)

Edit: the primary issue is getting windows paths to work on unix rather than the other way around.

Answer 1

The / is fully supported in win32 too.

Also see this related question

Answer 2

Windows will generally accept either \ or /,so standardizing on / may make your problem simpler as long as you have complete control over the filenames.

Answer 3

Have you considered creating a "file manager" class that will handle all of the file pathing issues for you? That way in your mail application, when you're loading a data file, you can call something like this.

LoadApplicationData(FileManager.GetDataFilePath)

Then your file manager will detect the environment that it is in and return the proper file path option. That way you can also accomodate for Win32 vs. Unix locatio standards (like Program Files vs /usr or whatever) as well.

Answer 4

Note that Win32 paths are complex when you consider drive letters (no analog on Unix) and the special 'forks' (MacOS pre-X term - likewise no analog on Unix in general, though MacOS X has them - surprise, surprise) that can be provided. Be careful.

Answer 5

Create a parser for your input to create a tree structure of nodes representing directories. Then you can 'save' by walking the tree and writing whatever delimiters you want or optionally doing different things, like checking if the directory exists or writing meta files. This is actually something that I am just now thinking would be useful for my own application :-)

Answer 6

You didn't say what language you are using, so I'm going to selfishly assume c/c++. boost, if you are willing to use it, has a filesystem library. Of course, if you are using a dynamic language, FS abstraction libraries probably already exist there too (e.g. in perl, File::Spec is quite standard).

Answer 7

You haven't told us what sort of files you are reading paths in from. I am going to assume that they are config files. In which case, there are many ways, IMHO the correct answer is to design your program to avoid manipulating paths, if possible. I posted an answer here: https://stackoverflow.com/a/40980510/2345997 which is relevant.

ways:

1. Add a command line option which allows a user to specify the path in question instead of reading it from a config file.
2. Add a command line option so that the user can specify a base path. Paths in the config file will be interpreted as located under this base path.
3. Split your config file into three. One file will have cross platform configuration, another file will have windows only configuration and a final file will have Linux only configuration. Then the user can specify the correct path for both Windows and Linux. On windows your program will read the cross-platform config file and the windows only config file. On Linux it will read the cross-platform file and the Linux only config file.
4. Add preprocessing to your config file parsing. This will allow you to have one config file where the user can make your program ignore some of the lines in the file depending on which OS the program is running on. Therefore, the user will be able to specify the path to the file twice. Once for Linux, and once for Windows.
5. Change the design so that the files are always located in the same directory as your executable - then the user only specifies file names in the config file rather than paths to files.
6. Use a simple function that switches "/" to "\". Then document to the user that they must specify paths as Linux paths and this transformation will be applied for windows.
7. Create your own path mini-language for this and document it to the user. E.g: "/" - specifies a directory separator, {root} - expands to the root of the filesystem, {cwd} - expands to the current directory, {app} - expands to the path to your application etc... Then the user can specify file paths like: {root}/myfiles/bob.txt on both platforms.
8. Some paths will work on both platforms. E.g: relative paths like ../my files/bill.txt. Restrict your application to only work with these paths. Document this limitation and how your application handles paths to the user.