github.com/mckael/restic@v0.8.3/internal/restic/idset.go (about)

     1  package restic
     2  
     3  import "sort"
     4  
     5  // IDSet is a set of IDs.
     6  type IDSet map[ID]struct{}
     7  
     8  // NewIDSet returns a new IDSet, populated with ids.
     9  func NewIDSet(ids ...ID) IDSet {
    10  	m := make(IDSet)
    11  	for _, id := range ids {
    12  		m[id] = struct{}{}
    13  	}
    14  
    15  	return m
    16  }
    17  
    18  // Has returns true iff id is contained in the set.
    19  func (s IDSet) Has(id ID) bool {
    20  	_, ok := s[id]
    21  	return ok
    22  }
    23  
    24  // Insert adds id to the set.
    25  func (s IDSet) Insert(id ID) {
    26  	s[id] = struct{}{}
    27  }
    28  
    29  // Delete removes id from the set.
    30  func (s IDSet) Delete(id ID) {
    31  	delete(s, id)
    32  }
    33  
    34  // List returns a slice of all IDs in the set.
    35  func (s IDSet) List() IDs {
    36  	list := make(IDs, 0, len(s))
    37  	for id := range s {
    38  		list = append(list, id)
    39  	}
    40  
    41  	sort.Sort(list)
    42  
    43  	return list
    44  }
    45  
    46  // Equals returns true iff s equals other.
    47  func (s IDSet) Equals(other IDSet) bool {
    48  	if len(s) != len(other) {
    49  		return false
    50  	}
    51  
    52  	for id := range s {
    53  		if _, ok := other[id]; !ok {
    54  			return false
    55  		}
    56  	}
    57  
    58  	// length + one-way comparison is sufficient implication of equality
    59  
    60  	return true
    61  }
    62  
    63  // Merge adds the blobs in other to the current set.
    64  func (s IDSet) Merge(other IDSet) {
    65  	for id := range other {
    66  		s.Insert(id)
    67  	}
    68  }
    69  
    70  // Intersect returns a new set containing the IDs that are present in both sets.
    71  func (s IDSet) Intersect(other IDSet) (result IDSet) {
    72  	result = NewIDSet()
    73  
    74  	set1 := s
    75  	set2 := other
    76  
    77  	// iterate over the smaller set
    78  	if len(set2) < len(set1) {
    79  		set1, set2 = set2, set1
    80  	}
    81  
    82  	for id := range set1 {
    83  		if set2.Has(id) {
    84  			result.Insert(id)
    85  		}
    86  	}
    87  
    88  	return result
    89  }
    90  
    91  // Sub returns a new set containing all IDs that are present in s but not in
    92  // other.
    93  func (s IDSet) Sub(other IDSet) (result IDSet) {
    94  	result = NewIDSet()
    95  	for id := range s {
    96  		if !other.Has(id) {
    97  			result.Insert(id)
    98  		}
    99  	}
   100  
   101  	return result
   102  }
   103  
   104  func (s IDSet) String() string {
   105  	str := s.List().String()
   106  	if len(str) < 2 {
   107  		return "{}"
   108  	}
   109  
   110  	return "{" + str[1:len(str)-1] + "}"
   111  }