Add 'executable' file type

[sharkdp]

Add a new executable/x filetype for --type/-t filtering that only shows files with the executable bit.

For Windows, we could either disable this feature completely or search for files with exe/bat/com/cmd/msi.. file extensions.

[sharkdp]

Note: we already have an is_executable function in output.rs which could be re-used for this. Currently, it always returns false on Windows.

[PramodBisht]

@sharkdp I want to pick this up if nobody is working on that.

[sharkdp]

@PramodBisht Sounds great!

[PramodBisht]

@sharkdp in PramodBisht@8f796e3 commit I have added changeset to show only executable, but I could not get running, maybe I am missing something. Could you give me some pointer what I am doing wrong?

[sharkdp]

These changes look good to me. How did you test this? Which OS are you on?

[PramodBisht]

@sharkdp I am using ubuntu 14.04. I executed target/debug/fd --type executable <some executable file name> I could not see any file list.

[sharkdp]

I just got a closer look. There is indeed a logical error in that code. Let's take a look at these lines in walk.rs:

if (entry_type.is_file() && !file_types.files)
    || (entry_type.is_dir() && !file_types.directories)
    || (entry_type.is_symlink() && !file_types.symlinks)
    || (output::is_executable(&entry.metadata().unwrap()) && !file_types.executables)
{
    return ignore::WalkState::Continue;
}

The way this works is that certain filesystem entries are skipped if one (or more) of the statements like entry_type.is_file() && !file_types.files are fulfilled.

If you specify --type executable (and no other --type arguments), then currently file_types.executables = true but all other file_types.* fields are set to false. This means that all files, directories and symlinks will be skipped (whether or not they are executable).

It looks like the executable flag should actually work a little different than the other three. What we want to see is files that are executable (directories and symlinks also have an executable flag, but we are typically not that interested in them). So I think we should rename file_types.executables to file_types.executables_only and set both files and executables_only to true if --type executable has been specified. Then, we can modify the above to:

if (entry_type.is_file() && !file_types.files)
    || (entry_type.is_dir() && !file_types.directories)
    || (entry_type.is_symlink() && !file_types.symlinks)
    || (!output::is_executable(&entry.metadata().unwrap()) && file_types.executables_only)
{
    return ignore::WalkState::Continue;
}

This would also allow us to specify --type executable in combination with --type directory and --type symlink.