DISK I/O
Read the comments of a file
I had this same question a couple of years ago. Rick Brown was kind enough to put this demo together. Thanks again Rick. This has been very helpful to me.
Joe:
In response to your message to the FutureBASIC mailing list, here's a short demo illustrating the use of those PBDT* functions.
'=======================
I re-visited this demo since Forrest posted his request, and I found that it doesn't quite work as written on my new (G3, OS 8.0) Mac. (Specifically, it seems to _set_ comments ok but doesn't _get_ them). Iplayed around with it and found that if I set dtpb.ioDTReqCount& to 200 before calling FN PBDTGetCommentSync, then it seems to work ok again. Inside Mac does not mention this as a required input parameter. Maybe this is something new with OS 8.x? At any rate, the version of the demo that I just uploaded to the FB webring has this fix in it.
' This is a simple demo which illustrates the
' use of routines which read & set Finder comments.
' Because this demo uses a simple "File Open" dialog
' to let the user select the file, it won't currently
' handle comments for alias files, folders nor volumes.
'=======================
COMPILE 0, _caseInsensitive
'========= constants =======
_ioDTRefNum = 24
_ioDTBuffer = 32
_ioDTReqCount = 36
_ioDTActCount = 40
'========= globals ======
DIM gAction
END GLOBALS
'========= functions =======
LOCAL FN PBDTGetPath(pBlkPtr&)
` move.l ^pBlkPtr&,a0 ;pblock
` moveq #$20,d0 ;selector
` dc.w $a260 ;HFSdispatch
` ext.l d0 ;result comes back in DO.w
END FN
'---------------------------------
LOCAL FN PBDTGetCommentSync(pBlkPtr&)
` move.l ^pBlkPtr&,a0 ;pblock
` moveq #$2a,d0 ;selector
` dc.w $a260 ;HFSdispatch
` ext.l d0 ;result comes back in DO.w
END FN
'---------------------------------
LOCAL FN PBDTSetCommentSync(pBlkPtr&)
` move.l ^pBlkPtr&,a0 ;pblock
` moveq #$28,d0 ;selector
` dc.w $a260 ;HFSdispatch
` ext.l d0 ;result comes back in DO.w
END FN
'---------------------------------
LOCAL FN PBDTFlush(pBlkPtr&, async)
LONG IF async
` move.l ^pBlkPtr&,a0
` moveq #$2b,d0
` dc.w $a660 ;async version of HFSdispatch
` move.w d0,^OSErr
XELSE
` move.l ^pBlkPtr&,a0
` moveq #$2b,d0
` dc.w $a260
` move.w d0,^OSErr
END IF
END FN = OSErr
'---------------------------------
LOCAL FN DoDialog
evnt = DIALOG(0)
id = DIALOG(evnt)
SELECT CASE evnt
CASE _btnClick
SELECT CASE id
CASE 1: gAction = 1 '(set comment)
CASE 2: gAction = 2 '(cancel)
END SELECT
END SELECT
END FN
'========= main =======
DIM dtpb.104, commentBuffer.200, wdpb.52
WINDOW OFF
WINDOW 1, "Comment Demo", (0,0)-(250,150), _docNoGrow+_noGoAway
TEXT _monaco, 9
EDIT FIELD 1, "", (10,30)-(240,120), _framed
TEXT _geneva, 12
BUTTON 1, _enable, "Set Comments", (140,130)-(240,146)
BUTTON 2, _enable, "Cancel", (10,130)-(100,146)
ON DIALOG FN DoDialog
DO
filename$ = FILES$(_fOpen, "",, vRefNum)
LONG IF filename$ <> ""
OSErr = 0
CLS
dtpb.ioCompletion& = _nil
dtpb.ioNamePtr& = _nil
dtpb.ioVRefNum% = vRefNum
OSErr = FN PBDTGetPath(@dtpb) '(to fill in the ioDTRefNum field)
LONG IF OSErr = _noErr
dtpb.ioNamePtr& = @filename$
dtpb.ioDTBuffer& = @commentBuffer
'Get the DirID corresponding to vRefNum:
wdpb.ioCompletion& = _nil
wdpb.ioNamePtr& = _nil
wdpb.ioVRefNum% = vRefNum
wdpb.ioWDIndex% = 0
wdpb.ioWDProcID& = _nil
wdpb.ioWDVRefNum% = 0 '(I.M. fails to explain why this is input!)
OSErr = FN GETWDINFO(@wdpb)
LONG IF OSErr = _noErr
dtpb.ioDirID& = wdpb.ioWDDirID&
dtpb.ioDTReqCount& = 200 ' Rick's fix
OSErr = FN PBDTGetCommentSync(@dtpb)
SELECT CASE OSErr
CASE _noErr
charCount = dtpb.ioDTActCount&
POKE @theComment$, charCount
BLOCKMOVE @commentBuffer, @theComment$+1, charCount
EDIT$(1) = theComment$
CASE _afpItemNotFound
EDIT$(1) = "" '(no comment)
OSErr = _noErr
CASE ELSE
BEEP: PRINT "PBDTGetCommentSync OSErr: "; OSErr
END SELECT
XELSE
BEEP: PRINT "GetWDInfo OSErr: "; OSErr
END IF
XELSE
BEEP: PRINT "PBDTGetPath OSErr: "; OSErr
END IF
gAction = 0
DO
HANDLEEVENTS
UNTIL gAction <> 0
LONG IF gAction = 1 AND OSErr = _noErr
'Set Comments:
theComment$ = LEFT$(EDIT$(1),200)
IF LEN(theComment$) > 0 THEN BLOCKMOVE @theComment$+1, @commentBuffer, LEN(theComment$)
dtpb.ioDTReqCount& = LEN(theComment$)
'(all the other required fields in dtpb are already filled in
'from above calls to PBDTGetPath and PBDTGetCommentSync. In
'general, the following fields must be filled in, before calling
'PBDTSetCommentSync: ioCompletion&, ioNamePtr&, ioDTRefNum%,
'ioDTBuffer&, ioDTReqCount&, and ioDirID&.)
OSErr = FN PBDTSetCommentSync(@dtpb)
LONG IF OSErr = _noErr
OSErr = FN PBDTFlush(@dtpb, _false)
LONG IF OSErr
BEEP: PRINT "PBDTFlush OSErr: "; OSErr
DELAY 3000
END IF
XELSE
BEEP: PRINT "PBDTSetComment OSErr: "; OSErr
DELAY 3000
END IF
END IF
END IF
UNTIL filename$ = ""
Rick