ev/pkg/driver/resolve-links/resolve-links.go

134 lines
2.7 KiB
Go

package resolvelinks
import (
"context"
"errors"
"go.sour.is/ev"
"go.sour.is/ev/pkg/driver"
"go.sour.is/ev/pkg/event"
"go.sour.is/pkg/lg"
)
type resolvelinks struct {
up driver.Driver
}
func New() *resolvelinks {
return &resolvelinks{}
}
func (r *resolvelinks) Apply(es *ev.EventStore) {
r.up = es.Driver
es.Driver = r
}
func (r *resolvelinks) Unwrap() driver.Driver {
return r.up
}
func (r *resolvelinks) Open(ctx context.Context, dsn string) (driver.Driver, error) {
ctx, span := lg.Span(ctx)
defer span.End()
return r.up.Open(ctx, dsn)
}
func (r *resolvelinks) EventLog(ctx context.Context, streamID string) (driver.EventLog, error) {
ctx, span := lg.Span(ctx)
defer span.End()
l, err := r.up.EventLog(ctx, streamID)
return &wrapper{l, r}, err
}
type wrapper struct {
up driver.EventLog
resolver *resolvelinks
}
func (r *wrapper) Unwrap() driver.EventLog {
return r.up
}
func (w *wrapper) Read(ctx context.Context, after int64, count int64) (event.Events, error) {
ctx, span := lg.Span(ctx)
defer span.End()
events, err := w.up.Read(ctx, after, count)
if err != nil {
return nil, err
}
err = w.resolvelinks(ctx, events)
return events, err
}
func (w *wrapper) ReadN(ctx context.Context, index ...uint64) (event.Events, error) {
ctx, span := lg.Span(ctx)
defer span.End()
events, err := w.up.ReadN(ctx, index...)
if err != nil {
return nil, err
}
err = w.resolvelinks(ctx, events)
return events, err
}
func (w *wrapper) Append(ctx context.Context, events event.Events, version uint64) (uint64, error) {
ctx, span := lg.Span(ctx)
defer span.End()
return w.up.Append(ctx, events, version)
}
func (w *wrapper) FirstIndex(ctx context.Context) (uint64, error) {
ctx, span := lg.Span(ctx)
defer span.End()
return w.up.FirstIndex(ctx)
}
func (w *wrapper) LastIndex(ctx context.Context) (uint64, error) {
ctx, span := lg.Span(ctx)
defer span.End()
return w.up.LastIndex(ctx)
}
func (w *wrapper) resolvelinks(ctx context.Context, events event.Events) error {
idx := make(map[string][]uint64)
ptrs := make(map[string][]int)
for i := range events {
e := events[i]
if e, ok := e.(*event.EventPtr); ok {
idx[e.StreamID] = append(idx[e.StreamID], e.Pos)
ptrs[e.StreamID] = append(ptrs[e.StreamID], i)
}
}
for streamID, ids := range idx {
d, err := w.resolver.EventLog(ctx, streamID)
if err != nil {
return err
}
ptr := ptrs[streamID]
lis, err := d.ReadN(ctx, ids...)
if err != nil && !errors.Is(err, ev.ErrNotFound) {
return err
}
for i := range lis {
meta := lis[i].EventMeta()
actual := events[ptr[i]].EventMeta()
meta.ActualPosition = actual.Position
meta.ActualStreamID = actual.ActualStreamID
lis[i].SetEventMeta(meta)
events[i] = lis[i]
}
}
return nil
}