/
store.go
108 lines (89 loc) · 2.27 KB
/
store.go
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package filter
import (
"context"
"errors"
"sync"
"time"
"github.com/google/uuid"
"golang.org/x/xerrors"
"github.com/filecoin-project/lotus/chain/types"
)
type Filter interface {
ID() types.FilterID
LastTaken() time.Time
SetSubChannel(chan<- interface{})
ClearSubChannel()
}
type FilterStore interface {
Add(context.Context, Filter) error
Get(context.Context, types.FilterID) (Filter, error)
Remove(context.Context, types.FilterID) error
NotTakenSince(when time.Time) []Filter // returns a list of filters that have not had their collected results taken
}
var (
ErrFilterAlreadyRegistered = errors.New("filter already registered")
ErrFilterNotFound = errors.New("filter not found")
ErrMaximumNumberOfFilters = errors.New("maximum number of filters registered")
)
func newFilterID() (types.FilterID, error) {
rawid, err := uuid.NewRandom()
if err != nil {
return types.FilterID{}, xerrors.Errorf("new uuid: %w", err)
}
id := types.FilterID{}
copy(id[:], rawid[:]) // uuid is 16 bytes, the last 16 bytes are zeroed
return id, nil
}
type memFilterStore struct {
max int
mu sync.Mutex
filters map[types.FilterID]Filter
}
var _ FilterStore = (*memFilterStore)(nil)
func NewMemFilterStore(maxFilters int) FilterStore {
return &memFilterStore{
max: maxFilters,
filters: make(map[types.FilterID]Filter),
}
}
func (m *memFilterStore) Add(_ context.Context, f Filter) error {
m.mu.Lock()
defer m.mu.Unlock()
if len(m.filters) >= m.max {
return ErrMaximumNumberOfFilters
}
if _, exists := m.filters[f.ID()]; exists {
return ErrFilterAlreadyRegistered
}
m.filters[f.ID()] = f
return nil
}
func (m *memFilterStore) Get(_ context.Context, id types.FilterID) (Filter, error) {
m.mu.Lock()
f, found := m.filters[id]
m.mu.Unlock()
if !found {
return nil, ErrFilterNotFound
}
return f, nil
}
func (m *memFilterStore) Remove(_ context.Context, id types.FilterID) error {
m.mu.Lock()
defer m.mu.Unlock()
if _, exists := m.filters[id]; !exists {
return ErrFilterNotFound
}
delete(m.filters, id)
return nil
}
func (m *memFilterStore) NotTakenSince(when time.Time) []Filter {
m.mu.Lock()
defer m.mu.Unlock()
var res []Filter
for _, f := range m.filters {
if f.LastTaken().Before(when) {
res = append(res, f)
}
}
return res
}