cap-primitives 0.26.0-patch1

Capability-based primitives
Documentation 
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use crate::fs::{FollowSymlinks, OpenOptions};
use std::fs;
use std::os::windows::fs::OpenOptionsExt;
use windows_sys::Win32::Storage::FileSystem::{
    FILE_FLAG_BACKUP_SEMANTICS, FILE_FLAG_OPEN_REPARSE_POINT,
};

/// Translate the given `cap_std` into `std` options. Also return a bool
/// indicating that the `trunc` flag was requested but could not be set,
/// so the file should be truncated manually after opening.
pub(in super::super) fn open_options_to_std(opts: &OpenOptions) -> (fs::OpenOptions, bool) {
    let mut trunc = opts.truncate;
    let mut manually_trunc = false;

    let mut custom_flags = match opts.follow {
        FollowSymlinks::Yes => opts.ext.custom_flags,
        FollowSymlinks::No => {
            if trunc && !opts.create_new && !opts.append && opts.write {
                // On Windows, truncating overwrites a symlink with a
                // non-symlink.
                manually_trunc = true;
                trunc = false;
            }
            opts.ext.custom_flags | FILE_FLAG_OPEN_REPARSE_POINT
        }
    };
    if opts.maybe_dir {
        custom_flags |= FILE_FLAG_BACKUP_SEMANTICS;
    }
    let mut std_opts = fs::OpenOptions::new();
    std_opts
        .read(opts.read)
        .write(opts.write)
        .append(opts.append)
        .truncate(trunc)
        .create(opts.create)
        .create_new(opts.create_new)
        .share_mode(opts.ext.share_mode)
        .custom_flags(custom_flags)
        .attributes(opts.ext.attributes);

    // Calling `sequence_qos_flags` with a value of 0 has the side effect
    // of setting `SECURITY_SQOS_PRESENT`, so don't call it if we don't
    // have any flags.
    if opts.ext.security_qos_flags != 0 {
        std_opts.security_qos_flags(opts.ext.security_qos_flags);
    }

    if let Some(access_mode) = opts.ext.access_mode {
        std_opts.access_mode(access_mode);
    }

    (std_opts, manually_trunc)
}