diff options
Diffstat (limited to 'nexgb/xgb.go')
| -rw-r--r-- | nexgb/xgb.go | 102 |
1 files changed, 79 insertions, 23 deletions
diff --git a/nexgb/xgb.go b/nexgb/xgb.go index b453427..26c0138 100644 --- a/nexgb/xgb.go +++ b/nexgb/xgb.go @@ -17,6 +17,11 @@ import ( ) const ( + // cookieBuffer represents the queue size of cookies existing at any + // point in time. The size of the buffer is really only important when + // there are many requests without replies made in sequence. Once the + // buffer fills, a round trip request is made to clear the buffer. + cookieBuffer = 1000 readBuffer = 100 writeBuffer = 100 ) @@ -32,7 +37,7 @@ type Conn struct { extensions map[string]byte eventChan chan eventOrError - cookieChan chan cookie + cookieChan chan *cookie xidChan chan xid seqChan chan uint16 reqChan chan *request @@ -68,7 +73,7 @@ func NewConnDisplay(display string) (*Conn, error) { conn.extensions = make(map[string]byte) - conn.cookieChan = make(chan cookie, 100) + conn.cookieChan = make(chan *cookie, cookieBuffer) conn.xidChan = make(chan xid, 5) conn.seqChan = make(chan uint16, 20) conn.reqChan = make(chan *request, 100) @@ -87,6 +92,12 @@ func (c *Conn) Close() { c.conn.Close() } +// DefaultScreen returns the Screen info for the default screen, which is +// 0 or the one given in the display argument to Dial. +func (c *Conn) DefaultScreen() *ScreenInfo { + return &c.Setup.Roots[c.defaultScreen] +} + // Id is used for all X identifiers, such as windows, pixmaps, and GCs. type Id uint32 @@ -95,6 +106,7 @@ type Id uint32 type Event interface { ImplementsEvent() Bytes() []byte + String() string } // newEventFuncs is a map from event numbers to functions that create @@ -188,7 +200,8 @@ func (c *Conn) newSequenceId() uint16 { // to match up replies with requests. // Since sequence ids can only be 16 bit integers we start over at zero when it // comes time to wrap. -// FIXME: 65,536 requests without replies cannot be made in a single sequence. +// N.B. As long as the cookie buffer is less than 2^16, there are no limitations +// on the number (or kind) of requests made in sequence. func (c *Conn) generateSeqIds() { seqid := uint16(1) for { @@ -206,13 +219,14 @@ func (c *Conn) generateSeqIds() { // The cookie is used to match up the reply/error. type request struct { buf []byte - cookie cookie + cookie *cookie } // newRequest takes the bytes an a cookie, constructs a request type, -// and sends it over the Conn.reqChan channel. It then returns the cookie -// (for convenience). -func (c *Conn) newRequest(buf []byte, cookie cookie) { +// and sends it over the Conn.reqChan channel. +// Note that the sequence number is added to the cookie after it is sent +// over the request channel. +func (c *Conn) newRequest(buf []byte, cookie *cookie) { c.reqChan <- &request{buf: buf, cookie: cookie} } @@ -220,15 +234,38 @@ func (c *Conn) newRequest(buf []byte, cookie cookie) { // the bytes to the wire and adds the cookie to the cookie queue. func (c *Conn) sendRequests() { for req := range c.reqChan { + // ho there! if the cookie channel is nearly full, force a round + // trip to clear out the cookie buffer. + // 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 + if !c.writeBuffer(c.getInputFocusRequest()) { + return + } + GetInputFocusCookie{cookie}.Reply() // wait for the buffer to clear + } + + req.cookie.Sequence = c.newSequenceId() c.cookieChan <- req.cookie - if _, err := c.conn.Write(req.buf); err != nil { - fmt.Fprintf(os.Stderr, "x protocol write error: %s\n", err) - close(c.reqChan) + if !c.writeBuffer(req.buf) { return } } } +// writeBuffer is a convenience function for writing a byte slice to the wire. +func (c *Conn) writeBuffer(buf []byte) bool { + if _, err := c.conn.Write(buf); err != nil { + fmt.Fprintf(os.Stderr, "x protocol write error: %s\n", err) + close(c.reqChan) + return false + } + return true +} + // readResponses is a goroutine that reads events, errors and // replies off the wire. // When an event is read, it is always added to the event channel. @@ -260,7 +297,15 @@ func (c *Conn) readResponses() { case 0: // This is an error // Use the constructor function for this error (that is auto // generated) by looking it up by the error number. - err = newErrorFuncs[int(buf[1])](buf) + newErrFun, ok := newErrorFuncs[int(buf[1])] + if !ok { + fmt.Fprintf(os.Stderr, + "BUG: " + + "Could not find error constructor function for error " + + "with number %d.", buf[1]) + continue + } + err = newErrFun(buf) seq = err.SequenceId() // This error is either sent to the event channel or a specific @@ -291,22 +336,23 @@ func (c *Conn) readResponses() { // Note that we AND the event number with 127 so that we ignore // the most significant bit (which is set when it was sent from // a SendEvent request). - event = newEventFuncs[int(buf[0] & 127)](buf) - // seq = event.SequenceId() // 0 for KeymapNotify + evNum := int(buf[0] & 127) + newEventFun, ok := newEventFuncs[evNum] + if !ok { + fmt.Fprintf(os.Stderr, + "BUG: " + + "Could not find event constructor function for event " + + "with number %d.", evNum) + continue + } + + event = newEventFun(buf) // Put the event into the queue. c.eventChan <- event // No more processing for events. continue - - // If this was a KeymapNotify event, then we don't do any more - // processing since we don't have any sequence id. - // if event != nil { - // if _, ok := event.(KeymapNotifyEvent); ok { - // continue - // } - // } } // At this point, we have a sequence number and we're either @@ -326,12 +372,17 @@ func (c *Conn) readResponses() { cookie.errorChan <- err } else { // asynchronous processing c.eventChan <- err + // if this is an unchecked reply, ping the cookie too + if cookie.pingChan != nil { + cookie.pingChan <- true + } } } else { // this is a reply if cookie.replyChan == nil { fmt.Fprintf(os.Stderr, "Reply with sequence id %d does not have a " + "cookie with a valid reply channel.\n", seq) + continue } else { cookie.replyChan <- replyBytes } @@ -344,10 +395,14 @@ func (c *Conn) readResponses() { case cookie.replyChan != nil && cookie.errorChan != nil: fmt.Fprintf(os.Stderr, "Found cookie with sequence id %d that is expecting a " + - "reply but will never get it.\n", cookie.Sequence) + "reply but will never get it. Currently on sequence " + + "number %d\n", cookie.Sequence, seq) // Unchecked requests with replies case cookie.replyChan != nil && cookie.pingChan != nil: - cookie.pingChan <- true + fmt.Fprintf(os.Stderr, + "Found cookie with sequence id %d that is expecting a " + + "reply (and not an error) but will never get it. " + + "Currently on sequence number %d\n", cookie.Sequence, seq) // Checked requests without replies case cookie.pingChan != nil && cookie.errorChan != nil: cookie.pingChan <- true @@ -368,6 +423,7 @@ func processEventOrError(everr eventOrError) (Event, Error) { return nil, ee default: fmt.Fprintf(os.Stderr, "Invalid event/error type: %T\n", everr) + return nil, nil } panic("unreachable") } |