repository.go

Documentation: github.com/launchdarkly/eventsource

     1  package eventsource
     2  
     3  import (
     4  	"sort"
     5  	"sync"
     6  )
     7  
     8  // SliceRepository is an example repository that uses a slice as storage for past events.
     9  type SliceRepository struct {
    10  	events map[string][]Event
    11  	lock   *sync.RWMutex
    12  }
    13  
    14  // NewSliceRepository creates a SliceRepository.
    15  func NewSliceRepository() *SliceRepository {
    16  	return &SliceRepository{
    17  		events: make(map[string][]Event),
    18  		lock:   &sync.RWMutex{},
    19  	}
    20  }
    21  
    22  func (repo SliceRepository) indexOfEvent(channel, id string) int {
    23  	return sort.Search(len(repo.events[channel]), func(i int) bool {
    24  		return repo.events[channel][i].Id() >= id
    25  	})
    26  }
    27  
    28  // Replay implements the event replay logic for the Repository interface.
    29  func (repo SliceRepository) Replay(channel, id string) (out chan Event) {
    30  	out = make(chan Event)
    31  	go func() {
    32  		defer close(out)
    33  		repo.lock.RLock()
    34  		defer repo.lock.RUnlock()
    35  		events := repo.events[channel][repo.indexOfEvent(channel, id):]
    36  		for i := range events {
    37  			out <- events[i]
    38  		}
    39  	}()
    40  	return
    41  }
    42  
    43  // Add adds an event to the repository history.
    44  func (repo *SliceRepository) Add(channel string, event Event) {
    45  	repo.lock.Lock()
    46  	defer repo.lock.Unlock()
    47  	i := repo.indexOfEvent(channel, event.Id())
    48  	if i < len(repo.events[channel]) && repo.events[channel][i].Id() == event.Id() {
    49  		repo.events[channel][i] = event
    50  	} else {
    51  		repo.events[channel] = append(repo.events[channel][:i], append([]Event{event}, repo.events[channel][i:]...)...)
    52  	}
    53  }
    54
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