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GreenCoast/internal/index/index.go
2025-08-21 20:56:38 -04:00

124 lines
2.3 KiB
Go

package index
import (
"bufio"
"encoding/json"
"os"
"path/filepath"
"sort"
"sync"
"time"
)
type opType string
const (
OpPut opType = "put"
OpDel opType = "del"
)
type record struct {
Op opType `json:"op"`
Hash string `json:"hash"`
Bytes int64 `json:"bytes,omitempty"`
StoredAt time.Time `json:"stored_at,omitempty"`
Private bool `json:"private,omitempty"`
}
type Entry struct {
Hash string `json:"hash"`
Bytes int64 `json:"bytes"`
StoredAt time.Time `json:"stored_at"`
Private bool `json:"private"`
}
type Index struct {
path string
mu sync.Mutex
}
func New(baseDir string) *Index {
return &Index{path: filepath.Join(baseDir, "index.jsonl")}
}
func (i *Index) AppendPut(e Entry) error {
i.mu.Lock()
defer i.mu.Unlock()
return appendRec(i.path, record{
Op: OpPut,
Hash: e.Hash,
Bytes: e.Bytes,
StoredAt: e.StoredAt,
Private: e.Private,
})
}
func (i *Index) AppendDelete(hash string) error {
i.mu.Lock()
defer i.mu.Unlock()
return appendRec(i.path, record{Op: OpDel, Hash: hash})
}
func appendRec(path string, r record) error {
if err := os.MkdirAll(filepath.Dir(path), 0o755); err != nil {
return err
}
f, err := os.OpenFile(path, os.O_CREATE|os.O_WRONLY|os.O_APPEND, 0o644)
if err != nil {
return err
}
defer f.Close()
enc := json.NewEncoder(f)
return enc.Encode(r)
}
func (i *Index) Snapshot() ([]Entry, error) {
i.mu.Lock()
defer i.mu.Unlock()
f, err := os.Open(i.path)
if os.IsNotExist(err) {
return nil, nil
}
if err != nil {
return nil, err
}
defer f.Close()
sc := bufio.NewScanner(f)
sc.Buffer(make([]byte, 0, 64*1024), 4*1024*1024)
type state struct {
Entry Entry
Deleted bool
}
m := make(map[string]state)
for sc.Scan() {
var rec record
if err := json.Unmarshal(sc.Bytes(), &rec); err != nil {
continue
}
switch rec.Op {
case OpPut:
m[rec.Hash] = state{Entry: Entry{
Hash: rec.Hash, Bytes: rec.Bytes, StoredAt: rec.StoredAt, Private: rec.Private,
}}
case OpDel:
s := m[rec.Hash]
s.Deleted = true
m[rec.Hash] = s
}
}
if err := sc.Err(); err != nil {
return nil, err
}
var out []Entry
for _, s := range m {
if !s.Deleted && s.Entry.Hash != "" {
out = append(out, s.Entry)
}
}
sort.Slice(out, func(i, j int) bool { return out[i].StoredAt.After(out[j].StoredAt) })
return out, nil
}