HyperAppleTalk 4
Volume Number: | | 5
|
Issue Number: | | 4
|
Column Tag: | | HyperChat
|
Related Info: AppleTalk Mgr
XCMD Corner: HyperAppleTalk IV
By Donald Koscheka, Arthur Young & Co., MacTutor Contributing Editor
Note: Source code files accompanying article are located on MacTech CD-ROM or source code disks.
I sometimes think that, to most programmers, the network is best left to the handful of specialists that ply their craft on this arcane art.
Think of the network as adding a new dimension to your programs, much as perspective enabled medieval artists to add depth and realism to their paintings. While many artists may have scoffed at perspective, I have no trouble believing that the populace was awed by its discovery. Perhaps networking will shine the same light as we enter the renaissance of computer programming.
If youve been following this column over the last three months, you may be asking yourself, Are we there yet? This month, we tie the pieces together by introducing the rest of AppleTalk XCMDs. I apologize for publishing listings last month that you cant really use until this month. I hope this issue makes up for it and in the future I will do my best to provide soup to nuts code in each issue.
Conceptually, an AppleTalk interface can be reduced to the six steps: (1) Open access to the transaction protocol and allocate any memory that will be needed to interface to it. I chose the AppleTalk Data Stream Protocol(ADSP). ADSPOpen hooks us up to ADSP, establishes a connection listener and returns the connection listeners socket address to Hypercard. NBPOpen initializes a data structure that we use to interface to NBP. The January 89 issue of this column provides the code for these XCMDs.
(2) Given the address of the connection listener, register a name and type with the network using the name binding protocol. Once registered, our entitys name and address will be listed in the directory.
(3) If we want to be able to dial up other entities, we next perform a lookup which returns all current names in the lookup table which acts just like a directory. The names are returned as a list of items to Hypercard without their addresses. This step is optional, if all you expect to do is respond to requests (as in the case of a server), then you dont need to know the names of the requesting entities.
(4) To call another entity, invoke the ADSPCall XCMD with the entitys name. ADSPCall extracts the network address from the lookup table using the routine NBPGetAddress. This technique allows us to de-couple names and addresses; your stacks need never be concerned with the address of an entity, the name is sufficient at the Hypercard script level.
(5) Once a connection is established with another entity (called the remote end), you send information to that entity using ADSPTalk. You receive information from the remote end using ADSPListen. ADSPListen is the heart of the interface, in addition to checking for incoming messages, it also monitors the status of all open connections.
(6) When the session completes, remove your name from the names table using the NBPUnregister XFCN. Once unregistered, close down the interface to ADSP with the ADSPClose and then close down your NBP interface with NBPClose.
--The XCMDS--
While the process is conceptually quite simple, the amount of code needed to implement this interface may seem overwhelming. The rest of this article focuses on ADSPCall, ADSPTalk, ADSPListen and ADSPHangup. Information on both NBP and the open and close xcmds are available in that last two installments of this column as well as in recently published literature from APDA.
(1) ADSPCall
ADSPCall (listing 1) first extracts the address of the entity from the lookup table using NBPGetAddress. If you pass it the name of a currently visible entity, you have a reasonable assurance that the call will complete.
Upon retrieving the address, adspcall walks the connection list checking to see if a connection already exists with the remote end. If not, it creates a connection by calling DSPCreate.
Outgoing calls are placed asynchronously, control is passed back to Hypercard while the call completes in the background. Asynchronous communications pays big dividends, adspcall attempts to establish the connection as many times as you request in the retry field. Waiting for a call to complete can hang the system, a particularly uncomfortable state for the user. If for any reason, the remote end has gone off line, Hypercard wont be stuck with an unbearable delay waiting for the call to timeout.
Outgoing calls, like all other transactions on the network, must be monitored by the listener. ADSPListen detects when the remote end picks up the phone.
To invoke ADSPCall from your script, use the following command line:
--1
-- get the name of the entity from the lookup table.
-- We let HyperAppleTalk handle the defaults for
-- retry, interval and buffer size.
--
-- The two above globals will have been initialized by
-- NBPOpen and ADSPOpen respectively.
--
global globalNBPData, globalADSPData
ADSPCall theEntity
(2) ADSPTalk
Once a connection is established with a remote end, we can send messages to that entity. Like ADSPCall, ADSPTalk uses NBPGetAddress to get the address given a name. Because NBPGetAddress returns 0 if the name had no corresponding address in the lookup table, we can determine whether we have a connection to the remote end. ADSPTalk scans the connection list to match the address with that of an entity in our connection list (pointed to bey adsp^.ends). AdspTalk calls DSPTalk (covered last month) to send the information. Outgoing messages are also sent asynchronously so that the user is not made to suffer any delays while the transmission completes.
Like ADSPCall, the method of invoking ADSPTalk is straightforward:
--2
-- theEntity is the name of the remote end that you
-- called using ADSPCall and the card field contains the
-- data that you wish to send to the remote end.
--
global globalNBPData, globalADSPData
ADSPTalk theEntity, card field outgoing message
(3) ADSPListen
The quality of any conversation depends more on the skill of the listener than that of the talker. This is no less true for the network - talking is the easy part, the listener does the hard part. Like any good listener, ADSPListen must perform several tasks at once -- (1) Answer incoming calls, (2) Monitor the status of outgoing calls, (3) Receive incoming messages and (4) periodically check the status of each connection.
Putting ADSPListen in the idle method of a card or stack provides a method for periodically checking up on each connection.
For each established connection an entry exists in our adsp^.ends list. While most of the data stored in the connection (cn) block is for our own use, the network keeps us apprised of the connections status via two records: the parameter block (pb) and the connection control block (ccb). The parameter block behaves as it would for any low-level I/O on the Macintosh, it is the interface to the ADSP device driver. The connection block is used by adsp to keep us up to date on the status of each connection. In essence, we relinquish control of the parameter block and the connection control block to ADSP. The rest of the structures in the connection data are for our own use.
To determine what is going on in any connection, we check the state field in the connection control block. The following states are currently supported (see listing 2 for the corresponding code):
sClosed: The connection went down for some reason or other. At this point, we have no choice but to Hang up.
sOpen: A connection opens in stages. When we first create or detect an opening connection, we set the mode to NOP indicating the connection is only half open. A half open connection is one in which only one of the two ends is ready. Receiving the sOpen state from the remote end informs us that our connection is now open.
A connection that is already open signals that its closing with the eClosed message. If a connection is closing, hang up on it.
The next two tasks, talking and listening, are monitored by Checkmessages. Recall that ADSPTalk queues outgoing calls; they complete some time in the future. Similarly, incoming messages can complete at any time. To determine whether any incoming or outgoing messages need attention, we issue a Status call to adsp. The ioCrefNum field of the dspParamBlock in checkMessages gets the driver number of the adsp driver. The ccbRefnum field gets the connection number of the connection we are checking.
The status call is issued synchronously, we must wait for it to complete before testing the status of a connection. If recvQPending is not 0, we have an incoming block of data. On input, we call ReadADSPData which will accumulate the data into the connections input buffer until ADSP signals that there is no more data with the end-of-message flag (eom).
ReadADSPData will read data from the connections input buffer into the handle we stored in conn^.inbuf (see listing 3). Accumulating data is a simple task : resize the handle by the number of bytes that we need to read in (given to us by adsp in recvQpending. If recvQpending is 0, there are no bytes to read). Once the handle is resized, point to the old end of the handle, and read the data directly into that are in memory. The read returns the exact number of bytes read in. If that number differs from recvQPending (under ordinary circumstances this wont happen), then resize the handle to reflect the actual number of bytes read in.
After reading the data, we check the end-of-message flag (eom) which ADSP sets only after it sends the last block of the message down stream. If eom is set, there is no more data to read. We can now send the data back to hypercard. If we know the name of the connection, we send it back to hypercard via the ADSPCaller global container. This gives your stack a way of determining who sent the input data. The data itself is put in the hypercard container, HyperADSPData. Once the data and name have been reported to Hypercard, we can optionally send a message back, perhaps to invoke some special input processing. If the connection stored a message in its callme field, we now invoke that message via a callback.
Monitoring outgoing calls is a bit simpler. If the connections sendQPending field is not 0, we still have outgoing data in the output buffer. In this case, dont do anything. If on the other hand, the send queue has emptied out and there was data in it (the connection outbuf field is not nil), then dispose the memory currently occupied by the output data.
The last task that ADSPListen must handle is responding to incoming calls. It does this by calling its respondtoListen Procedure. If a connection request is pending, the connection listeners ioResult will be set to noErr (a negative result means an error occurred, a positive result means that no connection requests are pending, the listener still has its ears to the wall).
If a connection request is pending, we can open up a connection to the remote end whose address is passed in the remoteCID field. Once the connection is established,we can try to discover its name by issuing a call to NBPGetName with the pending connections name. Knowing the name of an incoming caller is optional so we dont take extraordinary efforts to discover the name. If however, you needed the entities name (as in the case of a game), then you can do a lookup if NBPGetName turns up empty-handed. This is an advanced feature and, in the interest of space, Ive omitted it. If you absolutely need this capability, drop me a line.
Once the pending request is serviced, the connection listener can put its ear back to the wall by requeuing the connection listener call. The information needed to queue a listening request is already stored in the connection listeners parameter block (adsp^.pb). Requeuing the request becomes a simple call to PBControl with the connections parameter block.
The following script, added to your card, will do the trick:
--3
on idle
global globalNBPdata, globalADSPData
global adspCaller-- name of the caller global HyperADSPData
-- where incoming data goes
--
ADSPListen ShowData
end idle
-- Show data is the method to invoke to handle
-- incoming data. Assuming that we have a card field
-- named show me, the following method will display the
-- incoming message:
--
on ShowData
global HyperADSPData
put HyperAdspData into card field show me
end showdata
(4) ADSPHangup
Weve already seen how to detect and respond to a connection hanging up on us. Use ADSPHangup (listing 4) to inform the remote end that the connection is going down. Once again, the drill is the same: get the address from the lookup table, check to see that a connection exists with this entity and call DSPHangup to inform the entity that the connection is going down. We dont remove the connection from the connection list at this point because we have to wait for the remote end to acknowledge our disconnection request. ADSPListen receives this acknowledgement in the form of an eClosed message. Once closed, we can tear down the connection and deallocate its memory (dspRemove).
--4
--
-- A simple script for hanging up a connection
--
on Disconnect
global HyperADSPData, globalNBPData
ADSPHangup theEntity
End Disconnect
You now have a reasonably complete interface to AppleTalk. ADSP and NBP both offer more features than Ive been able to show you in a short time. Notably, the out of stream and forward reset features of ADSP enable some very powerful enhancements to the basic protocol. I chose not to discuss these features in this series because the average application can get by quite well without them. If, however, you are writing a network server in Hypercard, you may want to explore these features in more detail. I will be happy to present the code for a full implementation of ADSP. In keeping with the spirit of MacTutor, contact me immediately to report any bugs in the code. I can be reached through this Magazine or on AppleLink (N0735) or MacNet.
Next month, Im going to switch gears back into low and explore the file manager from within Hypercard.
Listing 1: ADSPCall.p
(********************************)
(* file: ADSPCall.p *)
(* *)
(* Establish a connection with*)
(* the entity whose name is *)
(* passed as a parameter. *)
(* *)
(* params[1] = Name of entity *)
(* params[2] = listen message *)
(* params[3] = number of retries*)
(* params[4] = retry interval *)
(* params[5] = Input buffer siz *)
(* params[6] = Output buffer siz*)
(* *)
(* If already connected, just*)
(* return with noErr *)
(* *)
(* Defaults:*)
(* Input Buffer = 578 *)
(* Output Buffer = 578 *)
(* Retry count = 0 *)
(* Retry interval= 0 *)
(* Out: the Result ::= error *)
(* message, empty if none.*)
(* *)
(* ---------------------------- *)
(* By: Donald Koscheka *)
(* Date:9-Jan-89 *)
(* All Rights Reserved *)
(* *)
(********************************)
(********************************
Build Sequence
pascal ADSPCall.p -o ADSPCall.p.o
link -m ENTRYPOINT -rt XCMD=1302 -sn Main=ADSPCall
ADSPCall.p.o
{libraries}Interface.o
-o YourStackNameHere
*********************************)
{$R-}
{$S ADSPCall}
UNIT Koscheka;
(*********************************)
INTERFACE
(*********************************)
Uses MemTypes, QuickDraw, OSIntf,
ToolIntf, PackIntf, HyperXCmd,
AppleTalk, ADSP, adspxcmd;
Procedure EntryPoint( paramPtr : XCmdPtr );
(*********************************)
IMPLEMENTATION
(*********************************)
TYPE Str31 = String[31];
PROCEDURE ADSPCall( paramPtr: XCmdPtr ); FORWARD;
Procedure EntryPoint( paramPtr : XCmdPtr );
Begin
ADSPCall( paramPtr );
End;
Procedure ADSPCall( paramPtr : XCmdPtr );
VAR
adsp : ADSPPtr;
error, terr: OSErr;
inBufSiz : Integer;
outBufSiz: Integer;
retry : Integer;
interval : Integer;
eAddr : AddrBlock;
cn: CBPtr;
nbp : NBPPtr;
found : BOOLEAN;
{$I XCmdGlue.inc }
{$I XCMDADSP.inc }
(*********************************)
BEGIN
error := noErr;
found := TRUE; {*** true if already established ***}
WITH paramPtr^ DO
BEGIN
IF (paramCount <> 0) AND (params[1]^ <> NIL) THEN
BEGIN
adsp := ADSPPtr(RetrieveData( GLOBALDSPDATA ));
IF adsp <> NIL THEN
BEGIN
adsp^.checkPoint := RECEIVING;
{**** Before we go too far, lets ***}
{*** look at some of the settings ***}
{*** set the retransmit count***}
IF params[3] <> NIL THEN
retry := StringToSHort( params[3]^ )
ELSE
retry := 0;
{*** Set the retransmit interval ***}
IF params[4] <> NIL THEN
interval := StringToSHort( params[4]^ )
ELSE
interval := 0;
{*** Set the input buffer size ***}
IF params[5] <> NIL THEN
inBufSiz := StringToSHort( params[5]^ )
ELSE
inBufSiz := ATPBSIZE;
{*** Set the output buffer size ***}
IF params[6] <> NIL THEN
outBufSiz := StringToSHort( params[6]^ )
ELSE
outBufSiz:= ATPBSIZE;
{*** (1) Get the entitys address ***}
HLock( Handle( params[1]) );
eAddr := NBPGetAddress( params[1]^ );
HUnlock( Handle( params[1] ) );
{*** Walk through the connection ***}
{*** list to see if the connection***}
{*** already exists.***}
IF LongInt(eAddr) <> 0 THEN
BEGIN
cn := adsp^.ends;
found := FALSE;
WHILE (NOT found) DO
IF cn = NIL THEN
found := TRUE
ELSE
IF LongInt( eAddr ) = LongInt( cn^.adr ) THEN
found := TRUE
ELSE
cn := cn^.next;
{*** If connection already exists ***}
{*** cn will not be NIL so we wont ***}
{*** have to reconnect the two ends,***}
{*** just fall out, otherwise, try to***}
{*** make the connection.***}
IF cn = NIL THEN {*** establish connection ***}
BEGIN
cn^.remName:= NBPGetName( eAddr );
cn := DSPCreate(eAddr,inBufSiz,
outBufSiz,retry,interval,params[2] );
IF cn <> NIL THEN
BEGIN
cn^.remName := NBPGetName( eAddr );
{*** try to discover the name ***}
IF cn^.remName = NIL THEN
BEGIN
nbp := NBPPtr(RetrieveData(GLOBALNBPDATA));
IF nbp <> NIL THEN
BEGIN
SendCardMessage(DoALookUp);
cn^.remName := NBPGetName( eAddr );
END;
END;
{*** Now dial for dollars***}
WITH cn^.dspPB DO
BEGIN
ioCRefNum := adsp^.dspRefNum;
ccbRefNum:= cn^.ccbRef;
csCode := dspOpen;
ocMode := ocRequest;
ioCompletion:= NIL;
remoteCID:= 0;{*** dont know this yet***}
localCID := 0;{*** adsp allocates id***}
remoteAddress:= eAddr;
filterAddress.aNet:= 0;
filterAddress.aNode := 0;
filterAddress.aSocket:= 0;
SendSeq:= 0;
RecvSeq:= 0;
SendWindow := 0;
attnSendSeq:= 0;
attnRecvSeq:= 0;
ocInterval := INTERVAL;
ocMaximum:= RETRY;
error := PBControl( @cn^.dspPB, ASYNC );
END;
END;
END;
END; {(LongInt(eAddr) <> 0) }
adsp^.checkPoint := CLOSE_OK;
END;
END;
returnValue := PasToZero( NumToStr( LongInt(error) ) );
END; {*** with paramPtr^ ***}
END;
end.
Listing 2: ADSPTalk.p
(****************************)
(* file: ADSPTalk.p *)
(* *)
(* Send information to an *)
(* established connection. *)
(* The connection must be *)
(* been established via the *)
(* ADSPCALL xcmd.*)
(* *)
(* In: *)
(* params[1] = entity name*)
(* of the remote end.*)
(* *)
(* ------------------------ *)
(* By: Donald Koscheka *)
(* Date:2-Mar-89 *)
(* All Rights Reserved *)
(* *)
(* ------------------------ *)
(****************************)
(*****************************
Build Sequence
pascal -o ADSPTalk.p.o ADSPTalk.p
link -m ENTRYPOINT -rt XCMD=1305 -sn Main=ADSPTalk
ADSPTalk.p.o
{libraries}Interface.o
-o YourStackNameHere
*****************************)
{$R-}
{$S ADSPTalk}
UNIT DummyUnit;
(****************************)
INTERFACE
(****************************)
Uses MemTypes, QuickDraw, OSIntf,
ToolIntf, PackIntf, HyperXCmd,
AppleTalk, ADSP, adspxcmd;
Procedure EntryPoint( paramPtr : XCmdPtr );
(****************************)
IMPLEMENTATION
(****************************)
TYPE Str31 = String[31];
PROCEDURE ADSPTalk( paramPtr: XCmdPtr ); FORWARD;
Procedure EntryPoint( paramPtr : XCmdPtr );
Begin
ADSPTalk( paramPtr );
End;
Procedure ADSPTalk( paramPtr : XCmdPtr );
VAR
adsp : ADSPPtr;
error : OSErr;
eAddr : AddrBlock;
cb: cbPtr;
{$I XCmdGlue.inc }
{$I XCMDADSP.inc }
BEGIN
error := noErr;
adsp := ADSPPtr(RetrieveData( GLOBALDSPDATA ));
IF(adsp <> NIL)
AND (paramPtr^.params[1] <> NIL)
AND (paramPtr^.params[2] <> NIL) THEN
BEGIN
adsp^.checkPoint := RECEIVING;
{*** (1) Get the entitys address ***}
HLock( paramPtr^.params[1] );
eAddr := NBPGetAddress( paramPtr^.params[1]^ );
cb := adsp^.ends;
{*** (2) Find entity in connection list***}
IF LongInt( eAddr ) <> 0 THEN
WHILE cb <> NIL DO
IF (LongInt(cb^.adr)=LongInt(eAddr))
AND (cb^.ccb.state=sOpen) THEN
BEGIN
error := DSPTalk(cb, paramPtr^.params[2] );
cb := NIL;
END
ELSE
cb := cb^.next;
adsp^.checkPoint := CLOSE_OK;
HUnlock( Handle(paramPtr^.params[1]) );
END;
paramPtr^.returnValue := PasToZero( NumToStr( LongInt(error) ) );
END;
end.
Listing 3: ADSPListen.p
(****************************)
(* file: ADSPListen.p *)
(* *)
(* Perform the following: *)
(* (1) Listen for incoming*)
(* calls on the connection*)
(* listener *)
(* (2) Check to see if any*)
(* outgoing calls have been*)
(* answered *)
(* (3) Check connections *)
(* for incoming data *)
(* (4) Check connections for*)
(* attention messages*)
(* *)
(* In: *)
(* params[1] = name of *)
(* message to call hypercard*)
(* with on incoming data *)
(* *)
(* Defaults:*)
(* container = HyperADSPData*)
(* message = none.*)
(* *)
(* ---------------------- *)
(* All Rights Reserved *)
(* *)
(* ------------------------ *)
(* By: Donald Koscheka *)
(* Date:2-Mar-89 *)
(* All Rights Reserved *)
(* *)
(* ------------------------ *)
(****************************)
(*****************************
Build Sequence
pascal -o {hpo}ADSPListen.p.o {adsp}ADSPListen.p
link -m ENTRYPOINT -rt XCMD=1303 -sn Main=ADSPListen
ADSPListen.p.o
{libraries}Interface.o
-o YourStackNameHere
******************************)
{$R-}
{$S ADSPListen}
UNIT Koscheka;
(****************************)
INTERFACE
(****************************)
Uses MemTypes, QuickDraw, OSIntf, ToolIntf, PackIntf, HyperXCmd, AppleTalk,
ADSP, adspxcmd;
Procedure EntryPoint( paramPtr : XCmdPtr );
(****************************)
IMPLEMENTATION
(****************************)
TYPE Str31 = String[31];
PROCEDURE ADSPListen( paramPtr: XCmdPtr ); FORWARD;
Procedure EntryPoint( paramPtr : XCmdPtr );
Begin
ADSPListen( paramPtr );
End;
Procedure ADSPListen( paramPtr : XCmdPtr );
VAR
myFlags: SignedByte;
{ flags from incoming unsolicited message }
adsp : ADSPPtr; { pointer to ADSP Control block}
error : OSErr;
err : OSErr;
cn,nn : cbPtr; { pointers to established conections}
nbp : NBPPtr;{ pointer to the memory NBP interface}
mybPtr : Ptr; { used for getting and setting flags}
{$I XCmdGlue.inc }
{$I XCMDADSP.inc }
PROCEDURE RespondToListen;
(********************************)
(* If the connection listener *)
(* has completed, then someone*)
(* is trying to call. If we can *)
(* initialize a connection, *)
(* acknowledge receipt of call.*)
(********************************)
VAR
err : Integer;
conn : CBPtr;
tH: Handle;
BEGIN
IF adsp^.pb.ioResult = noErr THEN
BEGIN {*** We Have an incoming call.***}
{*** Create a connection end to***}
{*** the caller and set the***}
{*** state to active indicating ***}
{*** the connection is accepted ***}
conn := DSPCreate(adsp^.pb.remoteAddress,
ATPBSIZE,ATPBSIZE,RETRY,INTERVAL,NIL );
IF conn <> NIL THEN
WITH conn^.dspPB DO
BEGIN {*** accept the connection request***}
ioCRefNum := adsp^.dspRefNum;
ioCompletion := NIL;
csCode := dspOpen;
ocMode := ocAccept;
ccbRefNum:= conn^.ccbRef;
remoteCID:= adsp^.pb.remoteCID;
localCID := 0;
remoteAddress := adsp^.pb.remoteAddress;
filterAddress.aNet:= 0;
filterAddress.aNode := 0;
filterAddress.aSocket := 0;
RecvSeq:= 0;
attnRecvSeq:= 0;
SendSeq:= adsp^.pb.SendSeq;
attnSendSeq:= adsp^.pb.attnSendSeq;
SendWindow := adsp^.pb.SendWindow;
ocInterval := INTERVAL;
ocMaximum:= RETRY;
err := PBControl( @conn^.dspPB, ASYNC );
{*** Call back Hypercard to inform ***}
{***it of an incoming call.***}
conn^.remName := NBPGetName( adsp^.pb.remoteAddress );
END;
{*** Reset connection listener to ***}
{*** wait for more calls ***}
err := PBControl( @adsp^.pb, ASYNC );
END
END;
PROCEDURE ReadADSPData( conn:CBPtr; cnt:Integer; callMe:Handle );
(********************************)
(* Poll the connection to *)
(* determine whether any *)
(* data is pending. If so, *)
(* read it and pass it back to *)
(* hypercard via the callback *)
(* mechanism. *)
(* *)
(* IN: *)
(* conn : pointer to connection *)
(* cnt : num. of bytes to read *)
(* callMe : callback method *)
(********************************)
VAR
Tempb : dspParamBlock;
err : Integer;
temp : LongInt;
inSize : LongInt;
globName: Str255;
tp: Ptr;
tH: Handle;
BEGIN
globName:= HyperADSPData;
WITH conn^ DO
BEGIN {*** read the data ***}
IF inBuf = NIL THEN
BEGIN
inBuf := NewHandle( LongInt(cnt) );
MoveHHi( inBuf );
HLock( inBuf );
tp:= inBuf^;
END
ELSE {*** inBuf already allocated, add to end of it***}
BEGIN
HUnlock( inBuf );
inSize := GetHandleSize(inBuf);
temp := inSize;
inSize := inSize + LongInt( cnt );
SetHandleSize( inBuf, inSize );
MoveHHi( inBuf );
HLock( inBuf );
temp := temp + Ord4( inBuf^ );
tp:= Pointer(temp);
END;
WITH Tempb DO {*** now read the data ***}
BEGIN
ioCRefNum := adsp^.dspRefNum;
ccbRefNum := conn^.ccbRef;
csCode := dspRead;
reqCount := cnt;
dataPtr := tp;
END;
err := PBControl( @Tempb, SYNC );
HUnlock( inBuf );
IF err=noErr THEN
BEGIN
inSize := GetHandleSize( inBuf );
inSize := inSize - (cnt-Tempb.actCount);
SetHandleSize( inBuf, inSize );
END;
IF (err=noErr) AND (Tempb.eom=1) THEN
BEGIN
IF inBuf <> NIL THEN {***Call back with data***}
BEGIN
IF remName <> NIL THEN
SetGlobal( ADSPCaller, remName );
tp := Pointer( Ord4( inBuf^ ) + LongInt(inSize) );
tp^ := 0;
SetGlobal( globName, inbuf );
DisposHandle( inbuf );
inbuf := NIL;
END;
IF callMe <> NIL THEN {***Set remote-end name***}
BEGIN
HLock( callMe );
ZeroToPas( Pointer( callMe^ ), globName );
HUnlock( callMe );
SendCardMessage( globName );
END;
END;
END;{*** read the data ***}
END;
Function CheckMessages( cb : cbPtr ): OSErr;
(************************************)
(* check this connection for: *)
(* (1) Completed Incoming Messages *)
(* (2) Completed Outgoing Messages *)
(************************************)
VAR
myErr : OSErr;
tpb : dspParamBlock;
BEGIN
WITH tpb DO
BEGIN
csCode := dspStatus;
ioCRefNum:= adsp^.dspRefNum;
ccbRefNum:= cn^.ccbRef;
END;
myErr := PBControl( @tpb, SYNC );
IF myErr = noErr THEN
BEGIN
{*** (3) Check for pending incoming data ***}
IF tpb.recvQPending <> 0 THEN
ReadADSPData( cn, tpb.recvQPending, paramPtr^.params[1] );
{***(4) See if any write operations have completed***}
IF (tpb.SendQPending = 0) AND (cn^.OutBuf <> NIL ) THEN
BEGIN
HUnlock( cn^.outBuf );
DisposHandle( cn^.outBuf );
cn^.outBuf := NIL;
END;
END; { myErr <> noErr }
CheckMessages := myErr;
END;
(**********************************)
(* ADSPListen *)
(**********************************)
BEGIN
error := noErr;
adsp := ADSPPtr(RetrieveData( GLOBALDSPDATA ));
IF adsp <> NIL THEN
BEGIN
adsp^.checkPoint := RECEIVING;
cn := adsp^.ends;
{***(2) Monitor status on all connections***}
WHILE cn <> NIL DO WITH cn^ DO
BEGIN
nn := next;
err := noErr;
CASE ccb.state OF { connection states }
sClosed: err := DSPHangUp( cn );
sOpen:
BEGIN
IF mode = NOP THEN {***connection is opening ***}
BEGIN {***inform Hypercard of connection***}
SetGlobal( ADSPCaller, remName );
SendCardMessage( ConnectionMade );
mode := EST;
END
ELSE
BEGIN {*** Check an established connection ***}
myBPtr := @cn^.ccb.userFlags;
IF BAND(myBPtr^, eClosed)=eClosed THEN
err := DSPHangUp( cn )
ELSE
BEGIN
err := CheckMessages( cn );
myBPtr^ := 0; { clear user flags}
END;
END;
END;
END; { case of connection states }
IF err <> noErr THEN error := err;
cn := nn;
END;
RespondToListen;{*** check for opening calls ***}
adsp^.checkPoint := CLOSE_OK;
END; {*** IF adsp <> NIL ***}
paramPtr^.returnValue := PasToZero( NumToStr( LongInt(err) ) );;
END;
end.
Listing 4: ADSPHangUp.p
(****************************)
(* file: ADSPHangUp.p *)
(* *)
(* Disconnect an established*)
(* connection and deallocate*)
(* the data associated with*)
(* the connection. *)
(* *)
(* In: params[1] Name of *)
(* the entity to hangup on*)
(* *)
(* Out: error message, *)
(* empty if none.*)
(* *)
(* ------------------------ *)
(* By: Donald Koscheka *)
(* Date:2-Mar-89 *)
(* All Rights Reserved *)
(* *)
(* ------------------------ *)
(****************************)
(*****************************
Build Sequence
pascal -o ADSPHangUp.p.o ADSPHangUp.p
link -m ENTRYPOINT -rt XCMD=1304 -sn Main=ADSPHangUp
ADSPHangUp.p.o
{libraries}Interface.o
-o YourStackNameHere
******************************)
{$R-}
{$S ADSPHangUp}
UNIT DummyUnit;
(****************************)
INTERFACE
(****************************)
Uses MemTypes, QuickDraw, OSIntf,
ToolIntf, PackIntf, HyperXCmd,
AppleTalk, ADSP, adspxcmd;
Procedure EntryPoint( paramPtr : XCmdPtr );
(****************************)
IMPLEMENTATION
(****************************)
TYPE Str31 = String[31];
PROCEDURE ADSPHangUp( paramPtr: XCmdPtr ); FORWARD;
Procedure EntryPoint( paramPtr : XCmdPtr );
Begin
ADSPHangUp( paramPtr );
End;
Procedure ADSPHangUp( paramPtr : XCmdPtr );
VAR
adsp : ADSPPtr;
error : OSErr;
pb: DSPParamBlock;
eAddr : AddrBlock;
cb: CBPtr;
{$I XCmdGlue.inc }
{$I XCMDADSP.inc }
(****************************)
BEGIN
error := noErr;
IF ( paramPtr^.paramCount > 0 )
AND ( paramPtr^.params[1] <> NIL ) THEN
BEGIN
adsp := ADSPPtr(RetrieveData( GLOBALDSPDATA ));
IF adsp <> NIL THEN
BEGIN
adsp^.checkPoint := RECEIVING;
{*** (1) Get the entitys address ***}
HLock( Handle(paramPtr^.params[1]) );
eAddr := NBPGetAddress( paramPtr^.params[1]^ );
cb := adsp^.ends;
{*** match the entity to the list ***}
IF LongInt(eAddr) <> 0 THEN
WHILE cb <> NIL DO
IF LongInt(cb^.adr ) = LongInt( eAddr ) THEN
BEGIN
error := DSPHangUp( cb );
cb := NIL;
END
ELSE
cb := cb^.next;
HUnlock( Handle(paramPtr^.params[1]) );
adsp^.checkPoint := CLOSE_OK;
END
END;
paramPtr^.returnValue := PasToZero( NumToStr( LongInt(error) ) );
END;
end.