have callback additions use a mutex

callback.go

@@ -50,12 +50,16 @@ func (c *Client) RunCallbacks(event *Event) {
 // AddCallbackHandler registers a callback (matching the Callback
 // interface) for the given command.
 func (c *Client) AddCallbackHandler(cmd string, callback Callback) {
+	c.cbMux.Lock()
 	c.callbacks[cmd] = append(c.callbacks[cmd], callback)
+	c.cbMux.Unlock()
 }
 
 // AddCallback registers the callback function for the given command.
 func (c *Client) AddCallback(cmd string, callback func(c *Client, e Event)) {
+	c.cbMux.Lock()
 	c.callbacks[cmd] = append(c.callbacks[cmd], CallbackFunc(callback))
+	c.cbMux.Unlock()
 }
 
 // AddBgCallback registers the callback function for the given command
@@ -63,7 +67,9 @@ func (c *Client) AddCallback(cmd string, callback func(c *Client, e Event)) {
 //
 // Runs after all other callbacks have been ran.
 func (c *Client) AddBgCallback(cmd string, callback func(c *Client, e Event)) {
+	c.cbMux.Lock()
 	c.callbacks["routine_"+cmd] = append(c.callbacks["routine_"+cmd], CallbackFunc(callback))
+	c.cbMux.Unlock()
 }
 
 // Callback is lower level implementation of Client.AddCallback().

main.go

@@ -24,6 +24,7 @@ import (
 	"io/ioutil"
 	"log"
 	"net"
+	"sync"
 	"time"
 )
 
@@ -37,12 +38,16 @@ type Client struct {
 	// Sender is a Sender{} interface implementation.
 	Sender Sender
 
-	// state represents the internal state
+	// state represents the throw-away state for the irc session.
 	state *state
 	// initTime represents the creation time of the client.
 	initTime time.Time
+
+	// cbLock is the internal locking mechanism for the callbacks map.
+	cbMux sync.Mutex
 	// callbacks is an internal mapping of COMMAND -> callback.
 	callbacks map[string][]Callback
+
 	// reader is the socket buffer reader from the IRC server.
 	reader *Decoder
 	// reader is the socket buffer write to the IRC server.