37 lines
982 B
Go
37 lines
982 B
Go
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// +build linux darwin freebsd solaris
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package continuity
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import (
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"fmt"
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"os"
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"syscall"
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)
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// hardlinkKey provides a tuple-key for managing hardlinks. This is system-
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// specific.
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type hardlinkKey struct {
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dev uint64
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inode uint64
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}
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// newHardlinkKey returns a hardlink key for the provided file info. If the
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// resource does not represent a possible hardlink, errNotAHardLink will be
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// returned.
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func newHardlinkKey(fi os.FileInfo) (hardlinkKey, error) {
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sys, ok := fi.Sys().(*syscall.Stat_t)
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if !ok {
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return hardlinkKey{}, fmt.Errorf("cannot resolve (*syscall.Stat_t) from os.FileInfo")
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}
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if sys.Nlink < 2 {
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// NOTE(stevvooe): This is not always true for all filesystems. We
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// should somehow detect this and provided a slow "polyfill" that
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// leverages os.SameFile if we detect a filesystem where link counts
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// is not really supported.
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return hardlinkKey{}, errNotAHardLink
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}
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return hardlinkKey{dev: uint64(sys.Dev), inode: uint64(sys.Ino)}, nil
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}
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