feat(cache): implement Delete

internal/btree/btree.go

@@ -498,6 +498,27 @@ func (d *DB) Get(hash *byte) []byte {
 }
 
 // Delete remove item with the given key 'hash' from the database file.
-func (d *DB) Delete(sha1 *byte) error {
-	return errors.New("impl me")
+func (d *DB) Delete(hash *byte) error {
+	var h [hashSize]byte
+	copyhash(&h[0], hash)
+
+	off := d.delete(d.top, &h[0])
+	if off == 0 {
+		return nil // not found key
+	}
+
+	d.top = collapse(d, d.top)
+	freeQueued(d)
+	d.flushSuper()
+
+	d.fd.Seek(off, io.SeekStart)
+	length, err := read32(d.fd) // len: 0
+	if err != nil {
+		return errors.Wrap(err, "btree I/O error")
+	}
+
+	d.freeChunk(off, int(length+4))
+	freeQueued(d)
+	d.flushSuper()
+	return nil
 }

internal/btree/btree_test.go

@@ -9,7 +9,7 @@ import (
 )
 
 func tempfile(t *testing.T) string {
-	temp, err := os.CreateTemp("", "temp.*.db")
+	temp, err := os.CreateTemp(".", "temp.*.db")
 	assert2.NoError(t, temp.Close())
 	assert2.NoError(t, err)
 	return temp.Name()
@@ -48,9 +48,14 @@ func TestBtree(t *testing.T) {
 	for i, tt := range tests {
 		assert2.Equal(t, []byte(tt), bt.Get(sha[i]))
 	}
-	assert2.NoError(t, bt.Close())
+
+	for i := range tests {
+		assert2.NoError(t, bt.Delete(sha[i]))
 	}
 
-func TestOpen(t *testing.T) {
-	println(tableSize)
+	for i := range tests {
+		assert2.Equal(t, []byte(nil), bt.Get(sha[i]))
+	}
+
+	assert2.NoError(t, bt.Close())
 }

internal/cache/cache.go

@@ -50,6 +50,16 @@ func (c *Cache) Get(md5 []byte) []byte {
 	return c.db.Get(&hash[0])
 }
 
+// Delete 删除指定缓存
+func (c *Cache) Delete(md5 []byte) {
+	c.lock.Lock()
+	defer c.lock.Unlock()
+
+	var hash [16]byte
+	copy(hash[:], md5)
+	_ = c.db.Delete(&hash[0])
+}
+
 // Init 初始化 Cache
 func Init() {
 	node, ok := base.Database["cache"]