70 lines
1.7 KiB
Go
70 lines
1.7 KiB
Go
// package driver defines interfaces to be used by driver implementations.
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package driver
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import (
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"context"
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"go.sour.is/ev/pkg/event"
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"go.sour.is/pkg/math"
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)
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type Driver interface {
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Open(ctx context.Context, dsn string) (Driver, error)
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EventLog(ctx context.Context, streamID string) (EventLog, error)
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}
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type EventLog interface {
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Read(ctx context.Context, after, count int64) (event.Events, error)
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ReadN(ctx context.Context, index ...uint64) (event.Events, error)
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Append(ctx context.Context, events event.Events, version uint64) (uint64, error)
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FirstIndex(context.Context) (uint64, error)
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LastIndex(context.Context) (uint64, error)
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}
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type EventLogWithTruncate interface {
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Truncate(context.Context, int64) error
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}
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type EventLogWithUpdate interface {
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LoadForUpdate(context.Context, event.Aggregate, func(context.Context, event.Aggregate) error) (uint64, error)
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}
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type Subscription interface {
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Recv(context.Context) <-chan bool
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Events(context.Context) (event.Events, error)
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Close(context.Context) error
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}
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type EventStream interface {
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Subscribe(ctx context.Context, streamID string, start int64) (Subscription, error)
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Send(ctx context.Context, streamID string, events event.Events) error
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}
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func GenerateStreamIDs(first, last uint64, after, count int64) ([]uint64, error) {
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// ---
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if first == 0 || last == 0 {
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return nil, nil
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}
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start, count := math.PagerBox(first, last, after, count)
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if count == 0 {
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return nil, nil
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}
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streamIDs := make([]uint64, math.Abs(count))
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for i := range streamIDs {
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streamIDs[i] = start
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if count > 0 {
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start += 1
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} else {
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start -= 1
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}
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if start < first || start > last {
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streamIDs = streamIDs[:i+1]
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break
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}
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}
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return streamIDs, nil
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}
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