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replace strings.Split(N) for strings.Cut() or alternatives

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Go 1.18 and up now provides a strings.Cut() which is better suited for
splitting key/value pairs (and similar constructs), and performs better:

```go
func BenchmarkSplit(b *testing.B) {
        b.ReportAllocs()
        data := []string{"12hello=world", "12hello=", "12=hello", "12hello"}
        for i := 0; i < b.N; i++ {
                for _, s := range data {
                        _ = strings.SplitN(s, "=", 2)[0]
                }
        }
}

func BenchmarkCut(b *testing.B) {
        b.ReportAllocs()
        data := []string{"12hello=world", "12hello=", "12=hello", "12hello"}
        for i := 0; i < b.N; i++ {
                for _, s := range data {
                        _, _, _ = strings.Cut(s, "=")
                }
        }
}
```

    BenchmarkSplit
    BenchmarkSplit-10            8244206               128.0 ns/op           128 B/op          4 allocs/op
    BenchmarkCut
    BenchmarkCut-10             54411998                21.80 ns/op            0 B/op          0 allocs/op

While looking at occurrences of `strings.Split()`, I also updated some for alternatives,
or added some constraints; for cases where an specific number of items is expected, I used `strings.SplitN()`
with a suitable limit. This prevents (theoretical) unlimited splits.

Signed-off-by: Sebastiaan van Stijn <github@gone.nl>
This commit is contained in:
Sebastiaan van Stijn
2022-11-04 09:05:39 +01:00
parent f90219d472
commit eaedadbed0
19 changed files with 96 additions and 106 deletions
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8
pkg/cri/opts/spec_windows.go
View File

@@ -243,15 +243,15 @@ func WithDevices(config *runtime.ContainerConfig) oci.SpecOpts {
hostPath := device.HostPath
if strings.HasPrefix(hostPath, "class/") {
hostPath = strings.Replace(hostPath, "class/", "class://", 1)
hostPath = "class://" + strings.TrimPrefix(hostPath, "class/")
}
splitParts := strings.SplitN(hostPath, "://", 2)
if len(splitParts) != 2 {
idType, id, ok := strings.Cut(hostPath, "://")
if !ok {
return fmt.Errorf("unrecognised HostPath format %v, must match IDType://ID", device.HostPath)
}
o := oci.WithWindowsDevice(splitParts[0], splitParts[1])
o := oci.WithWindowsDevice(idType, id)
if err := o(ctx, client, c, s); err != nil {
return fmt.Errorf("failed adding device with HostPath %v: %w", device.HostPath, err)
}