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swarm/storage/feed/lookup: renamed step hint to 'last'

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This commit is contained in:
Javier Peletier 2019-04-24 22:31:03 +02:00
parent 1109b73603
commit f23b88a102
1 changed files with 9 additions and 7 deletions
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16
swarm/storage/feed/lookup/algorithm_longearth.go
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@ -38,9 +38,9 @@ func LongEarthAlgorithm(ctx context.Context, now uint64, hint Epoch, read ReadFu
var gerr error // in case of error, this variable will be set var gerr error // in case of error, this variable will be set
var step stepFunc // For efficiency, the algorithm step is defined as a closure var step stepFunc // For efficiency, the algorithm step is defined as a closure
step = func(ctxS context.Context, t uint64, hint Epoch) interface{} { step = func(ctxS context.Context, t uint64, last Epoch) interface{} {
stepID := atomic.AddInt32(&stepCounter, 1) // give an ID to this call instance stepID := atomic.AddInt32(&stepCounter, 1) // give an ID to this call instance
trace(stepID, "init: t=%d, hint=%s", t, hint.String()) trace(stepID, "init: t=%d, last=%s", t, last.String())
var valueA, valueB, valueR interface{} var valueA, valueB, valueR interface{}
// initialize the three read contexts // initialize the three read contexts
@ -48,7 +48,7 @@ func LongEarthAlgorithm(ctx context.Context, now uint64, hint Epoch, read ReadFu
ctxA, cancelA := context.WithCancel(ctxS) // will handle the lookahead path ctxA, cancelA := context.WithCancel(ctxS) // will handle the lookahead path
ctxB, cancelB := context.WithCancel(ctxS) // will handle the lookback path ctxB, cancelB := context.WithCancel(ctxS) // will handle the lookback path
epoch := GetNextEpoch(hint, t) // calculate the epoch to look up in this step instance epoch := GetNextEpoch(last, t) // calculate the epoch to look up in this step instance
// define the lookAhead function, which will follow the path as if R was successful // define the lookAhead function, which will follow the path as if R was successful
lookAhead := func() { lookAhead := func() {
@ -61,14 +61,14 @@ func LongEarthAlgorithm(ctx context.Context, now uint64, hint Epoch, read ReadFu
// define the lookBack function, which will follow the path as if R was unsuccessful // define the lookBack function, which will follow the path as if R was unsuccessful
lookBack := func() { lookBack := func() {
if epoch.Base() == hint.Base() { if epoch.Base() == last.Base() {
return return
} }
base := epoch.Base() base := epoch.Base()
if base == 0 { if base == 0 {
return return
} }
valueB = step(ctxB, base-1, hint) valueB = step(ctxB, base-1, last)
} }
go func() { //goroutine to read the current epoch (R) go func() { //goroutine to read the current epoch (R)
@ -89,8 +89,10 @@ func LongEarthAlgorithm(ctx context.Context, now uint64, hint Epoch, read ReadFu
go func() { // goroutine to give a headstart to R and then launch lookahead. go func() { // goroutine to give a headstart to R and then launch lookahead.
defer cancelA() defer cancelA()
// if we are at the lowest level or this is the hint, then we cannot lookahead // if we are at the lowest level or the epoch to look up equals the last one,
if epoch.Level == LowestLevel || epoch.Equals(hint) { // then we cannot lookahead (can't go lower or repeat the same lookup, this would
// cause an infinite loop)
if epoch.Level == LowestLevel || epoch.Equals(last) {
return return
} }