1 package xmpp

     2 

     3 // Manages the stack of filters that can read and modify stanzas on

     4 // their way from the remote to the application.

     5 

     6 // Receive new filters on filterAdd; those new filters get added to

     7 // the top of the stack. Receive stanzas at the bottom of the stack on

     8 // input. Send stanzas out the top of the stack on output.

     9 func filterMgr(filterAdd <-chan Filter, input <-chan Stanza, output chan<- Stanza) {

    10 	botFiltIn := output

    11 	topFiltOut := input

    12 

    13 loop:

    14 	for {

    15 		select {

    16 		case stan, ok := <-input:

    17 			if !ok {

    18 				break loop

    19 			}

    20 			botFiltIn <- stan

    21 

    22 		case stan, ok := <-topFiltOut:

    23 			if !ok {

    24 				break loop

    25 			}

    26 			output <- stan

    27 

    28 		case filt := <-filterAdd:

    29 			newTop := make(chan Stanza)

    30 			go filt(topFiltOut, newTop)

    31 			topFiltOut = newTop

    32 		}

    33 	}

    34 	close(botFiltIn)

    35 }

    36 

    37 // Starts the filter chain. Filters will all interpose themselves

    38 // between srvIn and cliOut.

    39 func (cl *Client) startFilters(srvIn, cliIn <-chan Stanza) (<-chan Stanza, <-chan Stanza) {

    40 	cliOut := make(chan Stanza)

    41 	srvOut := make(chan Stanza)

    42 	go filterMgr(cl.sendFilterAdd, srvIn, cliOut)

    43 	go filterMgr(cl.recvFilterAdd, cliIn, srvOut)

    44 	return cliOut, srvOut

    45 }

    46 

    47 // AddRecvFilter adds a new filter to the top of the stack through which

    48 // incoming stanzas travel on their way up to the client.

    49 func (cl *Client) AddRecvFilter(filt Filter) {

    50 	if filt == nil {

    51 		return

    52 	}

    53 	cl.recvFilterAdd <- filt

    54 }

    55 

    56 // AddSendFilter adds a new filter to the top of the stack through

    57 // which outgoing stanzas travel on their way down from the client to

    58 // the network.

    59 func (cl *Client) AddSendFilter(filt Filter) {

    60 	if filt == nil {

    61 		return

    62 	}

    63 	cl.sendFilterAdd <- filt

    64 }