From fbcde2f322963d393b5e88707242168ce59b53eb Mon Sep 17 00:00:00 2001
From: lash <dev@holbrook.no>
Date: Wed, 2 Oct 2024 22:06:43 +0100
Subject: [PATCH] Implement timed data row db

---
 internal/storage/db.go         |  4 ++
 internal/storage/gdbm.go       |  1 +
 internal/storage/timed.go      | 75 ++++++++++++++++++++++++++++++++++
 internal/storage/timed_test.go | 35 ++++++++++++++++
 4 files changed, 115 insertions(+)
 create mode 100644 internal/storage/timed.go
 create mode 100644 internal/storage/timed_test.go

diff --git a/internal/storage/db.go b/internal/storage/db.go
index b2ac6a9..d53a765 100644
--- a/internal/storage/db.go
+++ b/internal/storage/db.go
@@ -10,6 +10,10 @@ const (
 	DATATYPE_USERSUB = 64
 )
 
+const (
+	SUBPREFIX_TIME = uint16(1)
+)
+
 type SubPrefixDb struct {
 	store db.Db
 	pfx []byte
diff --git a/internal/storage/gdbm.go b/internal/storage/gdbm.go
index eb959cf..61d53fc 100644
--- a/internal/storage/gdbm.go
+++ b/internal/storage/gdbm.go
@@ -12,6 +12,7 @@ var (
 	dbC map[string]chan db.Db
 )
 
+
 type ThreadGdbmDb struct {
 	db db.Db
 	connStr string
diff --git a/internal/storage/timed.go b/internal/storage/timed.go
new file mode 100644
index 0000000..2dce6b2
--- /dev/null
+++ b/internal/storage/timed.go
@@ -0,0 +1,75 @@
+package storage
+
+import (
+	"context"
+	"time"
+	"encoding/binary"
+
+	"git.defalsify.org/vise.git/db"
+)
+
+type TimedDb struct {
+	db.Db
+	tdb *SubPrefixDb
+	ttl time.Duration
+	parentPfx uint8
+}
+
+
+func NewTimedDb(db db.Db, ttl time.Duration) *TimedDb {
+	var b [2]byte
+	binary.BigEndian.PutUint16(b[:], SUBPREFIX_TIME)
+	sdb := NewSubPrefixDb(db, b[:])
+	return &TimedDb{
+		Db: db,
+		tdb: sdb,
+		ttl: ttl,
+	}
+}
+
+func(tib *TimedDb) SetPrefix(pfx uint8) {
+	tib.Db.SetPrefix(pfx)
+	tib.parentPfx = pfx
+}
+
+func(tib *TimedDb) Put(ctx context.Context, key []byte, val []byte) error {
+	t := time.Now()	
+	b, err := t.MarshalBinary()
+	if err != nil {
+		return err
+	}
+	err = tib.Db.Put(ctx, key, val)
+	if err != nil {
+		return err
+	}
+	k := append([]byte{tib.parentPfx}, key...)
+	defer func() {
+		tib.parentPfx = 0
+	}()
+	err = tib.tdb.Put(ctx, k, b)
+	if err != nil {
+		logg.ErrorCtxf(ctx, "failed to update timestamp of record", err)
+	}
+	return nil
+}
+
+func(tib *TimedDb) Get(ctx context.Context, key []byte) ([]byte, error) {
+	v, err := tib.Db.Get(ctx, key)
+	return v, err
+}
+
+func(tib *TimedDb) Stale(ctx context.Context, pfx uint8, key []byte) bool {
+	b := append([]byte{pfx}, key...)
+	v, err := tib.tdb.Get(ctx, b)
+	if err != nil {
+		logg.ErrorCtxf(ctx, "no time entry", "key", key)
+		return false
+	}
+	t_now := time.Now()	
+	t_then := time.Time{}
+	err = t_then.UnmarshalBinary(v)
+	if err != nil {
+		return false
+	}
+	return t_now.After(t_then.Add(tib.ttl))
+}
diff --git a/internal/storage/timed_test.go b/internal/storage/timed_test.go
new file mode 100644
index 0000000..391d351
--- /dev/null
+++ b/internal/storage/timed_test.go
@@ -0,0 +1,35 @@
+package storage
+
+import (
+	"context"
+	"testing"
+	"time"
+
+	"git.defalsify.org/vise.git/db"
+	memdb "git.defalsify.org/vise.git/db/mem"
+)
+
+func TestStaleDb(t *testing.T) {
+	ctx := context.Background()
+	mdb := memdb.NewMemDb()
+	err := mdb.Connect(ctx, "")
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	tdb := NewTimedDb(mdb, time.Duration(time.Millisecond))
+	tdb.SetPrefix(db.DATATYPE_USERDATA)
+	k := []byte("foo")
+	err = tdb.Put(ctx, k, []byte("bar"))
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	if tdb.Stale(ctx, db.DATATYPE_USERDATA, k) {
+		t.Fatal("expected not stale")
+	}
+	time.Sleep(time.Millisecond)
+	if !tdb.Stale(ctx, db.DATATYPE_USERDATA, k) {
+		t.Fatal("expected stale")
+	}
+}