perf: sync protocol and core hardening updates

internal/store/redisstore/code_cas.go

@@ -0,0 +1,147 @@
+package redisstore
+
+import (
+	"context"
+	"encoding/json"
+	"errors"
+	"fmt"
+
+	"github.com/redis/go-redis/v9"
+
+	"telesrv/internal/store"
+)
+
+const getPhoneCodeSnapshotScript = `
+local raw = redis.call('GET', KEYS[1])
+if not raw then
+  return ''
+end
+local decoded, record = pcall(cjson.decode, raw)
+if not decoded or type(record) ~= 'table'
+    or tonumber(record.Version or 0) ~= tonumber(ARGV[1])
+    or (record.Revision or '') == '' then
+  redis.call('DEL', KEYS[1])
+  return ''
+end
+return raw
+`
+
+const compareAndUpdatePhoneCodeScript = `
+local raw = redis.call('GET', KEYS[1])
+if not raw then
+  return 0
+end
+local decoded, record = pcall(cjson.decode, raw)
+if not decoded or type(record) ~= 'table'
+    or tonumber(record.Version or 0) ~= tonumber(ARGV[1])
+    or (record.Revision or '') == '' then
+  redis.call('DEL', KEYS[1])
+  return 0
+end
+if (record.Purpose or '') ~= '' or record.Revision ~= ARGV[2] then
+  return 0
+end
+redis.call('SET', KEYS[1], ARGV[3], 'KEEPTTL')
+return 1
+`
+
+const compareAndDeletePhoneCodeScript = `
+local raw = redis.call('GET', KEYS[1])
+if not raw then
+  return 0
+end
+local decoded, record = pcall(cjson.decode, raw)
+if not decoded or type(record) ~= 'table'
+    or tonumber(record.Version or 0) ~= tonumber(ARGV[1])
+    or (record.Revision or '') == '' then
+  redis.call('DEL', KEYS[1])
+  return 0
+end
+if (record.Purpose or '') ~= '' or record.Revision ~= ARGV[2] then
+  return 0
+end
+redis.call('DEL', KEYS[1])
+return 1
+`
+
+func (s *CodeStore) GetSnapshot(ctx context.Context, hash string) (store.PhoneCodeSnapshot, bool, error) {
+	value, err := s.c.Eval(
+		ctx,
+		getPhoneCodeSnapshotScript,
+		[]string{codeKey(hash)},
+		store.PhoneCodeVersionCurrent,
+	).Result()
+	if err != nil {
+		if errors.Is(err, redis.Nil) {
+			return store.PhoneCodeSnapshot{}, false, nil
+		}
+		return store.PhoneCodeSnapshot{}, false, fmt.Errorf("redis get phone code snapshot: %w", err)
+	}
+	raw, ok := value.(string)
+	if !ok {
+		return store.PhoneCodeSnapshot{}, false, fmt.Errorf("redis get phone code snapshot: unexpected result %T", value)
+	}
+	if raw == "" {
+		return store.PhoneCodeSnapshot{}, false, nil
+	}
+	var record store.PhoneCode
+	if err := json.Unmarshal([]byte(raw), &record); err != nil {
+		return store.PhoneCodeSnapshot{}, false, fmt.Errorf("redis get phone code snapshot decode: %w", err)
+	}
+	if record.Version != store.PhoneCodeVersionCurrent || record.Revision == "" {
+		return store.PhoneCodeSnapshot{}, false, fmt.Errorf("redis get phone code snapshot returned invalid version/revision")
+	}
+	return store.PhoneCodeSnapshot{Record: record, Revision: record.Revision}, true, nil
+}
+
+func (s *CodeStore) CompareAndUpdate(ctx context.Context, hash, expectedRevision string, next store.PhoneCode) (bool, error) {
+	if expectedRevision == "" || next.Version != store.PhoneCodeVersionCurrent || next.Purpose != "" {
+		return false, nil
+	}
+	revision, err := store.NewPhoneCodeRevisionToken()
+	if err != nil {
+		return false, err
+	}
+	next.Revision = revision
+	raw, err := json.Marshal(next)
+	if err != nil {
+		return false, fmt.Errorf("marshal compare-and-update phone code: %w", err)
+	}
+	value, err := s.c.Eval(
+		ctx,
+		compareAndUpdatePhoneCodeScript,
+		[]string{codeKey(hash)},
+		store.PhoneCodeVersionCurrent,
+		expectedRevision,
+		string(raw),
+	).Result()
+	if err != nil {
+		return false, fmt.Errorf("redis compare-and-update phone code: %w", err)
+	}
+	return redisCASApplied(value, "compare-and-update phone code")
+}
+
+func (s *CodeStore) CompareAndDelete(ctx context.Context, hash, expectedRevision string) (bool, error) {
+	if expectedRevision == "" {
+		return false, nil
+	}
+	value, err := s.c.Eval(
+		ctx,
+		compareAndDeletePhoneCodeScript,
+		[]string{codeKey(hash)},
+		store.PhoneCodeVersionCurrent,
+		expectedRevision,
+	).Result()
+	if err != nil {
+		return false, fmt.Errorf("redis compare-and-delete phone code: %w", err)
+	}
+	return redisCASApplied(value, "compare-and-delete phone code")
+}
+
+func redisCASApplied(value any, operation string) (bool, error) {
+	number, ok := value.(int64)
+	if !ok || (number != 0 && number != 1) {
+		return false, fmt.Errorf("redis %s: unexpected result %v (%T)", operation, value, value)
+	}
+	return number == 1, nil
+}