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package internal
import (
"encoding/binary"
"fmt"
"time"
)
type EventType int
const (
ChldProcStart = iota
ChldProcDone
ChldProcFailed
ChldProcHurt
ChldProcHealing
ChldProcHealed
ChldProcTimedOut
)
var eventName = map[EventType]string{
ChldProcStart: "child_start",
ChldProcDone: "child_done",
ChldProcFailed: "child_failed",
ChldProcHurt: "child_hurt",
ChldProcHealing: "child_healing",
ChldProcHealed: "child_healed",
ChldProcTimedOut: "child_timedout",
}
func (et EventType) String() string {
return eventName[et]
}
// SysLurchEventT mirrors the on-disk slot layout (32-byte header + payload).
type SysLurchEventT struct {
EventTime int64
EventID int64
EventKind EventType
Data1 int32
Data2 int32
PayloadLen uint32
Payload []byte
}
// EncodeEvent serializes ev into buf (must be >= SlotSize).
// Payload is truncated to fit if it exceeds the slot's payload capacity.
func EncodeEvent(buf []byte, ev SysLurchEventT) error {
if len(buf) < SlotSize {
return fmt.Errorf("encode event: buffer too small: %d < %d", len(buf), SlotSize)
}
payloadCap := SlotSize - SlotHeaderSize
payload := ev.Payload
if len(payload) > payloadCap {
payload = payload[:payloadCap]
}
binary.LittleEndian.PutUint64(buf[0:8], uint64(ev.EventTime))
binary.LittleEndian.PutUint64(buf[8:16], uint64(ev.EventID))
binary.LittleEndian.PutUint32(buf[16:20], uint32(ev.EventKind))
binary.LittleEndian.PutUint32(buf[20:24], uint32(ev.Data1))
binary.LittleEndian.PutUint32(buf[24:28], uint32(ev.Data2))
binary.LittleEndian.PutUint32(buf[28:32], uint32(len(payload)))
copy(buf[SlotHeaderSize:], payload)
// zero any leftover bytes from a previous longer write at this slot
for i := SlotHeaderSize + len(payload); i < SlotSize; i++ {
buf[i] = 0
}
return nil
}
// DecodeEvent deserializes a SysLurchEvent_t from buf (must be >= SlotSize).
func DecodeEvent(buf []byte) (SysLurchEventT, error) {
var ev SysLurchEventT
if len(buf) < SlotSize {
return ev, fmt.Errorf("decode event: buffer too small: %d < %d", len(buf), SlotSize)
}
ev.EventTime = int64(binary.LittleEndian.Uint64(buf[0:8]))
ev.EventID = int64(binary.LittleEndian.Uint64(buf[8:16]))
ev.EventKind = EventType(binary.LittleEndian.Uint32(buf[16:20]))
ev.Data1 = int32(binary.LittleEndian.Uint32(buf[20:24]))
ev.Data2 = int32(binary.LittleEndian.Uint32(buf[24:28]))
ev.PayloadLen = binary.LittleEndian.Uint32(buf[28:32])
if ev.PayloadLen > uint32(SlotSize-SlotHeaderSize) {
return ev, fmt.Errorf("decode event: invalid payload length %d", ev.PayloadLen)
}
payload := make([]byte, ev.PayloadLen)
copy(payload, buf[SlotHeaderSize:SlotHeaderSize+ev.PayloadLen])
ev.Payload = payload
return ev, nil
}
type pendingEntry struct {
deadline time.Time
}
// WatchMen is the in-process consumer view over a SharedRing.
type WatchMen struct {
ring *SharedRing
pending map[uint64]pendingEntry
}
func (w *WatchMen) MarkPending(slotIdx uint64, deadline time.Time) {
w.pending[slotIdx] = pendingEntry{deadline: deadline}
}
func NewWatchMen(ring *SharedRing) *WatchMen {
return &WatchMen{
ring: ring,
pending: make(map[uint64]pendingEntry),
}
}
// Ingest reads all unread events from the ring, advances ReadIndex, and
// returns them in order. Returns an error if the consumer has fallen behind
// and data has been overwritten (overflow).
func (w *WatchMen) Ingest() ([]SysLurchEventT, error) {
writeIdx := w.ring.WriteIndex()
readIdx := w.ring.ReadIndex()
if writeIdx < readIdx {
return nil, fmt.Errorf("ingest: corrupt indices: write %d < read %d", writeIdx, readIdx)
}
total := writeIdx - readIdx
if total == 0 {
return nil, nil
}
if total > uint64(MaxSlots) {
skipped := total - uint64(MaxSlots)
for s := readIdx; s < readIdx+skipped; s++ {
delete(w.pending, s)
}
readIdx += skipped
total = uint64(MaxSlots)
// TODO: caller needs to log skipped as dropped events
}
events := make([]SysLurchEventT, 0, total)
resolved := make(map[uint64]bool, total)
// first pass is decoding every slot in range, collect the resolved ones
for i := uint64(0); i < total; i++ {
slotIdx := readIdx + i
buf, err := w.ring.SlotBytes(slotIdx)
if err != nil {
return events, fmt.Errorf("ingest: read slot %d: %v", slotIdx, err)
}
ev, err := DecodeEvent(buf)
if err != nil {
return events, fmt.Errorf("ingest: decode slot %d: %v", slotIdx, err)
}
if ev.PayloadLen == 0 {
entry, tracked := w.pending[slotIdx]
if tracked && time.Now().After(entry.deadline) {
// means that this is still pending; worker is not done yet
// or it has timed out
delete(w.pending, slotIdx)
resolved[slotIdx] = true
ev.EventKind = ChldProcTimedOut
events = append(events, ev)
continue
}
w.pending[slotIdx] = entry // keeps tracking; deadline unchanged
continue
}
// rdy
delete(w.pending, slotIdx)
resolved[slotIdx] = true
events = append(events, ev)
}
// second pass advances the ReadIndex past the longest resolved
// prefix starting at readIdx
advanceTo := readIdx
for resolved[advanceTo] {
advanceTo++
}
if advanceTo > readIdx {
w.ring.SetReadIndex(advanceTo)
}
return events, nil
}
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