-- card: 33586 from stack: in.5
-- bmap block id: 9152
-- flags: 0000
-- background id: 3858
-- name: FileExists
----- HyperTalk script -----
on HideObjects
  hide cd btn "Try It!"
end HideObjects

on ShowObjects
  show cd btn "Try It!"
end ShowObjects


-- part 2 (button)
-- low flags: 00
-- high flags: A002
-- rect: left=82 top=185 right=219 bottom=175
-- title width / last selected line: 0
-- icon id / first selected line: 0 / 0
-- text alignment: 1
-- font id: 0
-- text size: 12
-- style flags: 8192
-- line height: 16
-- part name: Try it!
----- HyperTalk script -----
on mouseUp
  global errGlobal
  ask "Enter some full path name"
  if it = empty then exit mouseUp
  put fileExists(it,"nodialog:errGlobal") into itIsThere
  if last char of it = ":" then put "folder" into type
  else put "file" into type
  if itIsThere = "true" then
    answer "Good guess!  That" && type && "exists!"
  else
    answer "Sorry, that" && type && "does not exist!"
  end if
end mouseUp




-- part contents for background part 38
----- text -----
16/50

-- part contents for background part 20
----- text -----
FileExists - An XFCN to test whether or not a file/folder exists on a mounted volume.

FileExists(pathname, «"noDialog:"errorGlobal»)

This XFCN returns TRUE or FALSE depending on whether or not the file/folder specified by  Pathname is on a mounted volume.  It is useful to check for things like preferences stacks which your stack needs to install.



-- part contents for background part 42
----- text -----
{ FileExits(pathname «,"nodialog":errGlobal»)                 }
{}
{ XFCN to determin whether or not the specified file/folder   }
{ exists.  Makes no modifications to the file/folder.           }
{ Returns TRUE if the file/folder exists and FALSE if it does     }
{ not.  Assumes a full pathName is give in the parameter       }
{ PathName.                                                        }
{}
{   Written by:      Anup Murarka         Eric Carlson         }
{               ALINK:  SKEPTIC       ALINK:  cyNic   }
{                                   CIS:  76004,3356         }
{}
{               We are part of the Support Tools Development Group,     }
{               Apple Computer, Inc.      }
{}
{               please DO NOT contack Mac DTS for support of this code!    }
{}
{               please DO contact the authors for support of this code!     }
{}
{               Send comments, bug reports, requests to any of the above   }
{               E-mail addresses or to:}
{}
{                           (one of us)                  }
{                           Apple Computer, Inc.          }
{                           900 E. Hamilton, Ave.          }
{                           Campbell, CA   95008      }
{                           M/S 72-L                     }
{}
{   Copyright:   © 1989, 1990 by Apple Computer, Inc., all rights reserved.     }
{}
{ written by    : Anup Murarka                                                                               }
{ AppleLink  : Skeptic                                                                                      }
{ modification history                                                                                        }
{          Date              Initials                                    Comments                               }
{          ----          ------          ------------------------------------------------------}
{       8/16/89           akm         first written                                                           }
{       5/22/90           ec            removed upper case converion for A/UX compatibility.       }
{                                           Changed version to 1.1                                          }
{}
unit FileExists;

interface

    uses
        HyperXCmd;

    procedure MAIN (paramPtr: XCmdPtr);

implementation

    procedure FileExists (paramPtr: XCmdPtr);
    FORWARD;

    procedure MAIN (paramPtr: XCmdPtr);
    begin
        FileExists(paramPtr);
    end;

    procedure reportToUser (paramPtr: XCmdPtr;
                                    msgStr: str255);
{}
{ report something back to the user.  }
{ the last parameter (optional) to an external may contain }
 { "noDialog" or "noDialog:GlobalName".  GlobalName is the name }
 { of a HyperTalk global variable into which error messages will be }
 { placed.  we've decided to use this approach to avoid confusing }
{ an error message with a valid result being returned from an XFCN. }
{}
        var
            tempStr: str255;
    begin
{check the last param to see if the user requested that}
{ we suppress the error dialog }
        ZeroToPas(paramPtr, paramPtr^.params[paramPtr^.paramCount]^, tempStr);
        UprString(tempStr, true);
        if pos('NODIALOG', tempStr) = 0 then
    { no special error handling specified, throw up a dialog and return the error message }
            begin
                SendCardMessage(paramPtr, concat('answer "', msgStr, '"'));
                paramPtr^.returnValue := PasToZero(paramPtr, msgStr);
            end
        else if (pos(':', tempStr) > 0) then
    { requested global AND noDialog so we fill in the global and return empty }
            begin
                tempStr := copy(tempStr, pos(':', tempStr) + 1, length(tempStr));
                                                        { get the name of the HC global  to fill }
                SetGlobal(paramPtr, tempStr, PasToZero(paramPtr, msgStr));
                                                        { and fill it }
                paramPtr^.returnValue := PasToZero(paramPtr, '');      { return empty }
            end
        else
    { requested noDialog only so we return the error condition as the result }
            paramPtr^.returnValue := PasToZero(paramPtr, msgStr);
    end;     { procedure }

    function AskedForHelp (paramPtr: XCmdPtr;
                                    syntaxMsg: Str255;
                                    copyrightMsg: Str255): boolean;
{   check to see if the user sent a '?' or a '!' as }
{ the only parameter. if so we will respond with }
{ the calling syntax or the copyright/version info }
{ for this external }
{}
        var
            firstStr: str255;
    begin
        askedForHelp := false;
        if paramPtr^.paramCount = 1 then
            begin
                ZeroToPas(paramPtr, paramPtr^.params[1]^, firstStr);
                    { what is the first param? }
                if firstStr = '?' then
                    begin
                        reportToUser(paramPtr, syntaxMsg);
                        askedForHelp := true
                    end  { asked for help }
                else if firstStr = '!' then
                    begin
                        reportToUser(paramPtr, copyRightMsg);
                        askedForHelp := true
                    end;     { asked for copyright info }
            end;     { one parameter passed }
    end;     { function }

    function getParams (paramPtr: XCmdPtr;
                                    var PathToFind: str255): boolean;
        var
            numParams: integer;
            inputCh, syntaxStr, copyRtStr: str255;

    begin
        getParams := true;
        syntaxStr := 'FileExists(pathname «, “noDialog”:errGlobal»)';
        copyRtStr := '© 1989,1990 Apple Computer, Inc., v.1.1, by Anup Murarka';
        if askedForHelp(paramPtr, syntaxStr, copyRtStr) then
            begin
                getParams := false;
                exit(getParams);
            end;

        numParams := paramPtr^.paramCount;
        if (numParams < 1) or (numParams > 2) then
            begin
                getParams := false;
                reportToUser(paramPtr, syntaxStr);
                exit(getParams);
            end;

        ZeroToPas(paramPtr, paramPtr^.Params[1]^, PathToFind);
    end;         {GetParams}

    procedure FileExists (paramPtr: XCmdPtr);
        var
            getParamsOK: boolean;
            PathToFind: str255;
            paramBlock: CInfoPBRec;
            errorCode: OSErr;

    begin
    { fetch and validate the passed parameters}
        getParamsOK := getParams(paramPtr, PathToFind);
        if not (getParamsOK) then
            exit(FileExists);

    { initialize parameter block.  Since PathToFind is a full pathname, no other field is needed}
        zeroBytes(paramPtr, @paramBlock, sizeOf(paramBlock));
        paramBlock.ioNamePtr := @PathToFind;

    { get file/folder info}
        errorCode := PBGetCatInfo(@paramBlock, FALSE);

        if errorCode = noErr then
            paramPtr^.returnValue := pasToZero(paramPtr, 'TRUE')
        else if (errorCode = dirNFErr) or (errorCode = fnfErr) then
            paramPtr^.returnValue := pasToZero(paramPtr, 'FALSE')
        else
            begin
                paramPtr^.returnValue := pasToZero(paramPtr, 'FALSE');
                reportToUser(paramPtr, 'Sorry, an unexpected error has occured');
            end;

    end;         { procedure FileExists}

end.     { unit FileExists}