restic/internal/restorer/packheap.go

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package restorer
// packHeap is a heap of packInfo references
// @see https://golang.org/pkg/container/heap/
// @see https://en.wikipedia.org/wiki/Heap_(data_structure)
type packHeap struct {
elements []*packInfo
// returns true if download of any of the files is in progress
inprogress func(files map[*fileInfo]struct{}) bool
}
func (pq *packHeap) Len() int { return len(pq.elements) }
func (pq *packHeap) Less(a, b int) bool {
packA, packB := pq.elements[a], pq.elements[b]
ap := pq.inprogress(packA.files)
bp := pq.inprogress(packB.files)
if ap && !bp {
return true
}
if packA.cost < packB.cost {
return true
}
return false
}
func (pq *packHeap) Swap(i, j int) {
pq.elements[i], pq.elements[j] = pq.elements[j], pq.elements[i]
pq.elements[i].index = i
pq.elements[j].index = j
}
func (pq *packHeap) Push(x interface{}) {
n := len(pq.elements)
item := x.(*packInfo)
item.index = n
pq.elements = append(pq.elements, item)
}
func (pq *packHeap) Pop() interface{} {
old := pq.elements
n := len(old)
item := old[n-1]
item.index = -1 // for safety
pq.elements = old[0 : n-1]
return item
}