Add existsmissedtickets support.

extensions.go

@@ -226,6 +226,46 @@ func (c *Client) ExistsAddresses(addresses []dcrutil.Address) (string, error) {
 	return c.ExistsAddressesAsync(addresses).Receive()
 }
 
+// FutureExistsMissedTicketsResult is a future promise to deliver the result of
+// an ExistsMissedTicketsAsync RPC invocation (or an applicable error).
+type FutureExistsMissedTicketsResult chan *response
+
+// Receive waits for the response promised by the future and returns whether
+// or not the ticket exists in the missed ticket database.
+func (r FutureExistsMissedTicketsResult) Receive() (string, error) {
+	res, err := receiveFuture(r)
+	if err != nil {
+		return "", err
+	}
+
+	// Unmarshal the result as a string.
+	var exists string
+	err = json.Unmarshal(res, &exists)
+	if err != nil {
+		return "", err
+	}
+	return exists, nil
+}
+
+// ExistsMissedTicketsAsync returns an instance of a type that can be used to
+// get the result of the RPC at some future time by invoking the Receive
+// function on the returned instance.
+func (c *Client) ExistsMissedTicketsAsync(hashes []*chainhash.Hash) FutureExistsMissedTicketsResult {
+	hashBlob := make([]byte, len(hashes)*chainhash.HashSize)
+	for i, hash := range hashes {
+		copy(hashBlob[i*chainhash.HashSize:(i+1)*chainhash.HashSize],
+			hash[:])
+	}
+	cmd := dcrjson.NewExistsMissedTicketsCmd(hex.EncodeToString(hashBlob))
+	return c.sendCmd(cmd)
+}
+
+// ExistsMissedTickets returns a hex-encoded bitset describing whether or not
+// ticket hashes exists in the missed ticket database.
+func (c *Client) ExistsMissedTickets(hashes []*chainhash.Hash) (string, error) {
+	return c.ExistsMissedTicketsAsync(hashes).Receive()
+}
+
 // FutureExistsExpiredTicketsResult is a future promise to deliver the result
 // of a FutureExistsExpiredTicketsResultAsync RPC invocation (or an
 // applicable error).