Initial commit

application/command/commands.go

@@ -0,0 +1,72 @@
+// Sshwifty - A Web SSH client
+//
+// Copyright (C) 2019 Rui NI <nirui@gmx.com>
+//
+// This program is free software: you can redistribute it and/or modify
+// it under the terms of the GNU Affero General Public License as
+// published by the Free Software Foundation, either version 3 of the
+// License, or (at your option) any later version.
+//
+// This program is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU Affero General Public License for more details.
+//
+// You should have received a copy of the GNU Affero General Public License
+// along with this program.  If not, see <https://www.gnu.org/licenses/>.
+
+package command
+
+import (
+	"errors"
+	"fmt"
+
+	"github.com/niruix/sshwifty/application/log"
+	"github.com/niruix/sshwifty/application/network"
+)
+
+// Consts
+const (
+	MaxCommandID = 0x0f
+)
+
+// Errors
+var (
+	ErrCommandRunUndefinedCommand = errors.New(
+		"Undefined Command")
+)
+
+// Command represents a command handler machine builder
+type Command func(l log.Logger, w StreamResponder, d network.Dial) FSMMachine
+
+// Commands contains data of all commands
+type Commands [MaxCommandID + 1]Command
+
+// Register registers a new command
+func (c *Commands) Register(id byte, cb Command) {
+	if id > MaxCommandID {
+		panic("Command ID must be not greater than MaxCommandID")
+	}
+
+	if (*c)[id] != nil {
+		panic(fmt.Sprintf("Command %d already been registered", id))
+	}
+
+	(*c)[id] = cb
+}
+
+// Run creates command executer
+func (c Commands) Run(
+	id byte, l log.Logger, w StreamResponder, dial network.Dial) (FSM, error) {
+	if id > MaxCommandID {
+		return FSM{}, ErrCommandRunUndefinedCommand
+	}
+
+	cc := c[id]
+
+	if cc == nil {
+		return FSM{}, ErrCommandRunUndefinedCommand
+	}
+
+	return newFSM(cc(l, w, dial)), nil
+}