SetIfAbsent #77
SetIfAbsent #77
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Looking good, needs tests.
The boolean constants now flying around can be a little hard to follow. Consider adding two new boolean type wrappers for N/OVERWRITE for the parameter and UN/MODIFIED for the return value, so their meaning is transparent wherever they are used.
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I had a bit of a go of extending this but pushing the |
hamt.go
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| @@ -19,6 +19,26 @@ import ( | |||
| const bucketSize = 3 | |||
| const defaultBitWidth = 8 | |||
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| //----------------------------------------------------------------------------- | |||
| // Boolean constants | |||
| type overwrite = bool | |||
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For the compiler to help us use these correctly, could you remove the = here and define the consts like OVERWRITE = overwrite(false)?
hamt.go
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| // SetIfAbsent sets key k to value v only if k is not already set to some value. | ||
| // Returns true if the value mapped to k is changed by this operation | ||
| // is set, false otherwise. |
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| // is set, false otherwise. | |
| // false otherwise. |
hamt.go
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| @@ -575,17 +625,17 @@ func (n *Node) cleanChild(chnd *Node, cindex byte) error { | |||
| // cleanNode()). Recursive calls use the same arguments on child nodes but | |||
| // note that `hv.Next()` is not idempotent. Each call will increment the number | |||
| // of bits chomped off the hash digest for this key. | |||
| func (n *Node) modifyValue(ctx context.Context, hv *hashBits, k []byte, v *cbg.Deferred) error { | |||
| func (n *Node) modifyValue(ctx context.Context, hv *hashBits, k []byte, v *cbg.Deferred, overwrite bool) (modified, error) { | |||
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| func (n *Node) modifyValue(ctx context.Context, hv *hashBits, k []byte, v *cbg.Deferred, overwrite bool) (modified, error) { | |
| func (n *Node) modifyValue(ctx context.Context, hv *hashBits, k []byte, v *cbg.Deferred, replace overwrite) (modified, error) { |
hamt.go
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| } | ||
| } | ||
| return ErrNotFound | ||
| return false, ErrNotFound |
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| return false, ErrNotFound | |
| return UNMODIFIED, ErrNotFound |
hamt_test.go
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| val1 := []byte("owl bear") | ||
| key := "favorite-animal" | ||
| success, err := begn.SetIfAbsent(ctx, key, val1) | ||
| if err != nil { |
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We depend on testify already, so require.NoError(err).
Closes #75 with the
SetIfAbsentapproachmodifyValuenow returns a boolean indicating whether or not it has changed the subtreemodifyValuenow takes in an overwrite boolean which only allows overwriting existing keys when trueSetIfAbsentexported functionTests still needed