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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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19
metadata/gc.go
View File

@@ -443,13 +443,10 @@ func (c *gcContext) references(ctx context.Context, tx *bolt.Tx, node gc.Node, f
return c.sendLabelRefs(node.Namespace, bkt, fn)
case ResourceSnapshot, resourceSnapshotFlat:
parts := strings.SplitN(node.Key, "/", 2)
if len(parts) != 2 {
ss, name, ok := strings.Cut(node.Key, "/")
if !ok {
return fmt.Errorf("invalid snapshot gc key %s", node.Key)
}
ss := parts[0]
name := parts[1]
bkt := getBucket(tx, bucketKeyVersion, []byte(node.Namespace), bucketKeyObjectSnapshots, []byte(ss), []byte(name))
if bkt == nil {
// Node may be created from dead edge
@@ -563,7 +560,7 @@ func (c *gcContext) scanAll(ctx context.Context, tx *bolt.Tx, fn func(ctx contex
}
c.all(func(n gc.Node) {
fn(ctx, n)
_ = fn(ctx, n)
})
return nil
@@ -598,14 +595,14 @@ func (c *gcContext) remove(ctx context.Context, tx *bolt.Tx, node gc.Node) error
case ResourceSnapshot:
sbkt := nsbkt.Bucket(bucketKeyObjectSnapshots)
if sbkt != nil {
parts := strings.SplitN(node.Key, "/", 2)
if len(parts) != 2 {
ss, key, ok := strings.Cut(node.Key, "/")
if !ok {
return fmt.Errorf("invalid snapshot gc key %s", node.Key)
}
ssbkt := sbkt.Bucket([]byte(parts[0]))
ssbkt := sbkt.Bucket([]byte(ss))
if ssbkt != nil {
log.G(ctx).WithField("key", parts[1]).WithField("snapshotter", parts[0]).Debug("remove snapshot")
return ssbkt.DeleteBucket([]byte(parts[1]))
log.G(ctx).WithField("key", key).WithField("snapshotter", ss).Debug("remove snapshot")
return ssbkt.DeleteBucket([]byte(key))
}
}
case ResourceLease: