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@ -2,7 +2,11 @@ package util |
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// initial version comes from https://hackernoon.com/asyncawait-in-golang-an-introductory-guide-ol1e34sg
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// initial version comes from https://hackernoon.com/asyncawait-in-golang-an-introductory-guide-ol1e34sg
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import "context" |
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import ( |
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"container/list" |
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"context" |
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"sync" |
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) |
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type Future interface { |
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type Future interface { |
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Await() interface{} |
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Await() interface{} |
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@ -18,22 +22,26 @@ func (f future) Await() interface{} { |
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type LimitedAsyncExecutor struct { |
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type LimitedAsyncExecutor struct { |
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executor *LimitedConcurrentExecutor |
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executor *LimitedConcurrentExecutor |
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futureList *list.List |
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futureListCond *sync.Cond |
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} |
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} |
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func NewLimitedAsyncExecutor(limit int) *LimitedAsyncExecutor { |
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func NewLimitedAsyncExecutor(limit int) *LimitedAsyncExecutor { |
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return &LimitedAsyncExecutor{ |
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return &LimitedAsyncExecutor{ |
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executor: NewLimitedConcurrentExecutor(limit), |
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executor: NewLimitedConcurrentExecutor(limit), |
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futureList: list.New(), |
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futureListCond: sync.NewCond(&sync.Mutex{}), |
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} |
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} |
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} |
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} |
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func (ae *LimitedAsyncExecutor) Execute(job func() interface{}) Future { |
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func (ae *LimitedAsyncExecutor) Execute(job func() interface{}) { |
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var result interface{} |
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var result interface{} |
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c := make(chan struct{}) |
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c := make(chan struct{}) |
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ae.executor.Execute(func() { |
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ae.executor.Execute(func() { |
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defer close(c) |
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defer close(c) |
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result = job() |
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result = job() |
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}) |
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}) |
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return future{await: func(ctx context.Context) interface{} { |
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f := future{await: func(ctx context.Context) interface{} { |
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select { |
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select { |
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case <-ctx.Done(): |
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case <-ctx.Done(): |
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return ctx.Err() |
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return ctx.Err() |
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@ -41,4 +49,18 @@ func (ae *LimitedAsyncExecutor) Execute(job func() interface{}) Future { |
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return result |
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return result |
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} |
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} |
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}} |
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}} |
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ae.futureListCond.L.Lock() |
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ae.futureList.PushBack(f) |
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ae.futureListCond.Signal() |
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ae.futureListCond.L.Unlock() |
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} |
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func (ae *LimitedAsyncExecutor) NextFuture() Future { |
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ae.futureListCond.L.Lock() |
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for ae.futureList.Len() == 0 { |
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ae.futureListCond.Wait() |
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} |
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f := ae.futureList.Remove(ae.futureList.Front()) |
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ae.futureListCond.L.Unlock() |
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return f.(Future) |
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} |
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} |