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authorAndrew Gallant <jamslam@gmail.com>2013-08-11 19:33:56 -0400
committerPřemysl Janouch <p@janouch.name>2018-09-08 16:49:16 +0200
commit5d96993ee16d821b9448f4532328cb7caad223c9 (patch)
treec0ce43da366509d1c1573faf44d14c6f5155e68d /nexgb/xgb.go
parent3658686aeea7acc61621782c7c1e6dad66517479 (diff)
downloadhaven-5d96993ee16d821b9448f4532328cb7caad223c9.tar.gz
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Fixed a nasty bug where closing could cause ReadFull to crash
the program. Close #4.
Diffstat (limited to 'nexgb/xgb.go')
-rw-r--r--nexgb/xgb.go40
1 files changed, 29 insertions, 11 deletions
diff --git a/nexgb/xgb.go b/nexgb/xgb.go
index 3078c17..c894be1 100644
--- a/nexgb/xgb.go
+++ b/nexgb/xgb.go
@@ -61,6 +61,7 @@ type Conn struct {
xidChan chan xid
seqChan chan uint16
reqChan chan *request
+ closing chan chan struct{}
// Extensions is a map from extension name to major opcode. It should
// not be used. It is exported for use in the extension sub-packages.
@@ -100,6 +101,7 @@ func NewConnDisplay(display string) (*Conn, error) {
conn.seqChan = make(chan uint16, seqBuffer)
conn.reqChan = make(chan *request, reqBuffer)
conn.eventChan = make(chan eventOrError, eventBuffer)
+ conn.closing = make(chan chan struct{}, 1)
go conn.generateXIds()
go conn.generateSeqIds()
@@ -109,9 +111,9 @@ func NewConnDisplay(display string) (*Conn, error) {
return conn, nil
}
-// Close closes the connection to the X server.
+// Close gracefully closes the connection to the X server.
func (c *Conn) Close() {
- c.conn.Close()
+ close(c.reqChan)
}
// Event is an interface that can contain any of the events returned by the
@@ -292,7 +294,6 @@ func (c *Conn) NewRequest(buf []byte, cookie *Cookie) {
// the bytes to the wire and adds the cookie to the cookie queue.
// It is meant to be run as its own goroutine.
func (c *Conn) sendRequests() {
- defer close(c.reqChan)
defer close(c.cookieChan)
for req := range c.reqChan {
@@ -301,17 +302,27 @@ func (c *Conn) sendRequests() {
// Note that we circumvent the request channel, because we're *in*
// the request channel.
if len(c.cookieChan) == cookieBuffer-1 {
- cookie := c.NewCookie(true, true)
- cookie.Sequence = c.newSequenceId()
- c.cookieChan <- cookie
- c.writeBuffer(c.getInputFocusRequest())
- cookie.Reply() // wait for the buffer to clear
+ c.noop()
}
-
req.cookie.Sequence = c.newSequenceId()
c.cookieChan <- req.cookie
c.writeBuffer(req.buf)
}
+ response := make(chan struct{})
+ c.closing <- response
+ c.noop() // Flush the response reading goroutine.
+ <-response
+ c.conn.Close()
+}
+
+// noop circumvents the usual request sending goroutines and forces a round
+// trip request manually.
+func (c *Conn) noop() {
+ cookie := c.NewCookie(true, true)
+ cookie.Sequence = c.newSequenceId()
+ c.cookieChan <- cookie
+ c.writeBuffer(c.getInputFocusRequest())
+ cookie.Reply() // wait for the buffer to clear
}
// writeBuffer is a convenience function for writing a byte slice to the wire.
@@ -342,12 +353,19 @@ func (c *Conn) readResponses() {
)
for {
+ select {
+ case respond := <-c.closing:
+ respond <- struct{}{}
+ return
+ default:
+ }
+
buf := make([]byte, 32)
err, event, seq = nil, nil, 0
if _, err := io.ReadFull(c.conn, buf); err != nil {
- logger.Printf("Read error: %s", err)
- logger.Fatal("A read error is unrecoverable. Exiting...")
+ logger.Println("A read error is unrecoverable.")
+ panic(err)
}
switch buf[0] {