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package commitquery
import "slices"
// MergeBases computes fully reduced merge bases using one query context.
func MergeBases(ctx *Context, left, right NodeIndex) ([]NodeIndex, error) {
if left == right {
return []NodeIndex{left}, nil
}
err := paintDownToCommon(ctx, left, []NodeIndex{right}, 0)
if err != nil {
return nil, err
}
candidates := collectMarkedResults(ctx)
if len(candidates) <= 1 {
slices.SortFunc(candidates, ctx.Compare)
return candidates, nil
}
ctx.ClearTouchedMarks(allMarks)
reduced, err := removeRedundant(ctx, candidates)
if err != nil {
return nil, err
}
slices.SortFunc(reduced, ctx.Compare)
return reduced, nil
}
func paintDownToCommon(ctx *Context, left NodeIndex, rights []NodeIndex, minGeneration uint64) error {
ctx.BeginMarkPhase()
ctx.SetMarks(left, markLeft)
if len(rights) == 0 {
ctx.SetMarks(left, markResult)
return nil
}
queue := newPriorityQueue(ctx)
queue.PushNode(left)
for _, right := range rights {
ctx.SetMarks(right, markRight)
queue.PushNode(right)
}
lastGeneration := generationInfinity
for queueHasNonStale(ctx, queue) {
idx := queue.PopNode()
generation := ctx.EffectiveGeneration(idx)
if generation > lastGeneration {
return errBadGenerationOrder
}
lastGeneration = generation
if generation < minGeneration {
break
}
flags := ctx.Marks(idx) & (markLeft | markRight | markStale)
if flags == (markLeft | markRight) {
ctx.SetMarks(idx, markResult)
flags |= markStale
}
for _, parent := range ctx.Parents(idx) {
if ctx.HasAllMarks(parent, flags) {
continue
}
ctx.SetMarks(parent, flags)
queue.PushNode(parent)
}
}
return nil
}
func queueHasNonStale(ctx *Context, queue *priorityQueue) bool {
for _, idx := range queue.items {
if !ctx.HasAnyMarks(idx, markStale) {
return true
}
}
return false
}
func collectMarkedResults(ctx *Context) []NodeIndex {
out := make([]NodeIndex, 0, 4)
for _, idx := range ctx.touched {
if !ctx.HasAnyMarks(idx, markResult) {
continue
}
if ctx.HasAnyMarks(idx, markStale) {
continue
}
out = append(out, idx)
}
return out
}
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