github.com/filecoin-project/specs-actors/v4@v4.0.2/actors/util/adt/set.go (about)

     1  package adt
     2  
     3  import (
     4  	"github.com/filecoin-project/go-state-types/abi"
     5  	cid "github.com/ipfs/go-cid"
     6  )
     7  
     8  // Set interprets a Map as a set, storing keys (with empty values) in a HAMT.
     9  type Set struct {
    10  	m *Map
    11  }
    12  
    13  // AsSet interprets a store as a HAMT-based set with root `r`.
    14  // The HAMT is interpreted with branching factor 2^bitwidth.
    15  func AsSet(s Store, r cid.Cid, bitwidth int) (*Set, error) {
    16  	m, err := AsMap(s, r, bitwidth)
    17  	if err != nil {
    18  		return nil, err
    19  	}
    20  
    21  	return &Set{
    22  		m: m,
    23  	}, nil
    24  }
    25  
    26  // NewSet creates a new HAMT with root `r` and store `s`.
    27  // The HAMT has branching factor 2^bitwidth.
    28  func MakeEmptySet(s Store, bitwidth int) (*Set, error) {
    29  	m, err := MakeEmptyMap(s, bitwidth)
    30  	if err != nil {
    31  		return nil, err
    32  	}
    33  	return &Set{m}, nil
    34  }
    35  
    36  // Root return the root cid of HAMT.
    37  func (h *Set) Root() (cid.Cid, error) {
    38  	return h.m.Root()
    39  }
    40  
    41  // Put adds `k` to the set.
    42  func (h *Set) Put(k abi.Keyer) error {
    43  	return h.m.Put(k, nil)
    44  }
    45  
    46  // Has returns true iff `k` is in the set.
    47  func (h *Set) Has(k abi.Keyer) (bool, error) {
    48  	return h.m.Get(k, nil)
    49  }
    50  
    51  // Removes `k` from the set, if present.
    52  // Returns whether the key was previously present.
    53  func (h *Set) TryDelete(k abi.Keyer) (bool, error) {
    54  	return h.m.TryDelete(k)
    55  }
    56  
    57  // Removes `k` from the set, expecting it to be present.
    58  func (h *Set) Delete(k abi.Keyer) error {
    59  	return h.m.Delete(k)
    60  }
    61  
    62  // ForEach iterates over all values in the set, calling the callback for each value.
    63  // Returning error from the callback stops the iteration.
    64  func (h *Set) ForEach(cb func(k string) error) error {
    65  	return h.m.ForEach(nil, cb)
    66  }
    67  
    68  // Collects all the keys from the set into a slice of strings.
    69  func (h *Set) CollectKeys() (out []string, err error) {
    70  	return h.m.CollectKeys()
    71  }