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  • How to get File Summary Info

    Author: 2007-09-05 08:46:16 From:

    On Windows 2000 you can right-click in Explorer to get the file properties on any file and can associate summary information to any type of files, including even text files.

    For Word or Excel documents (compound files) the summary information is a part of document itself. For other files the way of storing additional information are different. This feature are only available on volumes formatted with NTFS. The NTFS implementation stores property sets in alternate streams of an NTFS file. The alternate streams must be copied when the main file is copied. However, not all file systems support such streams. For example, if an NTFS file with property sets is copied to a FAT volume, only the data in the file is copied; the property set is lost.

    First thing you probably want do is to detect whether the current volume is NTFS:

    // IsNTFS() - Verifies whether the file's volume is NTFS
    function IsNTFS(AFileName : string) : boolean;
    var
    fso, drv : OleVariant;
    begin
    IsNTFS := False;
    fso := CreateOleObject('Scripting.FileSystemObject');
    drv := fso.GetDrive(fso.GetDriveName(AFileName));
     if drv.FileSystem = 'NTFS' then
      IsNTFS := True;
    end;
    

    But how to read these properties? Is it really nessesary to work with a streams? No, NTFS file system 5.0 provides an implementation of IPropertySetStorage interface for files on an NTFS volume when the files themselves are not compound files. To get a pointer to the NTFS implementation of IPropertySetStorage, we have to call the StgCreateStorageEx function:

    function StgOpenStorageEx (
     const pwcsName : POleStr;  //Pointer to the path of the
                                //file containing storage object
     grfMode : LongInt;         //Specifies the access mode for the object
     stgfmt : DWORD;            //Specifies the storage file format
     grfAttrs : DWORD;          //Reserved; must be zero
     pStgOptions : Pointer;     //Address of STGOPTIONS pointer
     reserved2 : Pointer;       //Reserved; must be zero
     riid : PGUID;              //Specifies the GUID of the interface pointer
     out stgOpen :              //Address of an interface pointer
     IStorage ) : HResult; stdcall; external 'ole32.dll';

    All Microsoft Windows 2000 applications should use this new function, StgOpenStorageEx, instead of StgOpenStorage, to take advantage of the enhanced Windows 2000 Structured Storage features.

    The implementation of IPropertySetStorage on NTFS file system is similar with compound file implementation and available only on Windows 2000. Windows 95 and Windows NT 4.0 and earlier versions cannot access this interface. However, you cannot obtain the NTFS implementation of IPropertySetStorage for a compound file. When opening a compound file with StgOpenStorage, specifying the STGFMT_FILE enumeration value results in an error.

    The next function dumps all properties of the specific file. By changing the STGFMT_FILE flag in the StgOpenStorageEx call to STGMT_ANY you can open a Structured Storage property set or an NTFS file system property set.

    function GetFileSummaryInfo(const FileName: WideString): String;
    
    const
    FmtID_SummaryInformation: TGUID =     '{F29F85E0-4FF9-1068-AB91-08002B27B3D9}';
    FMTID_DocSummaryInformation : TGUID = '{D5CDD502-2E9C-101B-9397-08002B2CF9AE}';
    FMTID_UserDefinedProperties : TGUID = '{D5CDD505-2E9C-101B-9397-08002B2CF9AE}';
    IID_IPropertySetStorage : TGUID =     '{0000013A-0000-0000-C000-000000000046}';
    
    const
    STGFMT_FILE = 3; //Indicates that the file must not be a compound file.
                     //This element is only valid when using the StgCreateStorageEx
                     //or StgOpenStorageEx functions to access the NTFS file system
                     //implementation of the IPropertySetStorage interface.
                     //Therefore, these functions return an error if the riid
                     //parameter does not specify the IPropertySetStorage interface,
                     //or if the specified file is not located on an NTFS file system
                     //volume.
    
    STGFMT_ANY = 4; //Indicates that the system will determine the file type and
                    //use the appropriate structured storage or property set
                    //implementation.
                    //This value cannot be used with the StgCreateStorageEx function.
    
    
    // Summary Information
     PID_TITLE        = 2;
     PID_SUBJECT      = 3;
     PID_AUTHOR       = 4;
     PID_KEYWORDS     = 5;
     PID_COMMENTS     = 6;
     PID_TEMPLATE     = 7;
     PID_LASTAUTHOR   = 8;
     PID_REVNUMBER    = 9;
     PID_EDITTIME     = 10;
     PID_LASTPRINTED  = 11;
     PID_CREATE_DTM   = 12;
     PID_LASTSAVE_DTM = 13;
     PID_PAGECOUNT    = 14;
     PID_WORDCOUNT    = 15;
     PID_CHARCOUNT    = 16;
     PID_THUMBNAIL    = 17;
     PID_APPNAME      = 18;
     PID_SECURITY     = 19;
    
     // Document Summary Information
     PID_CATEGORY     = 2;
     PID_PRESFORMAT   = 3;
     PID_BYTECOUNT    = 4;
     PID_LINECOUNT    = 5;
     PID_PARCOUNT     = 6;
     PID_SLIDECOUNT   = 7;
     PID_NOTECOUNT    = 8;
     PID_HIDDENCOUNT  = 9;
     PID_MMCLIPCOUNT  = 10;
     PID_SCALE        = 11;
     PID_HEADINGPAIR  = 12;
     PID_DOCPARTS     = 13;
     PID_MANAGER      = 14;
     PID_COMPANY      = 15;
     PID_LINKSDIRTY   = 16;
     PID_CHARCOUNT2   = 17;
    
    var
     I: Integer;
     PropSetStg: IPropertySetStorage;
     PropSpec: array of TPropSpec;
     PropStg: IPropertyStorage;
     PropVariant: array of TPropVariant;
     Rslt: HResult;
     S: String;
     Stg: IStorage;
     PropEnum: IEnumSTATPROPSTG;
     HR : HResult;
     PropStat: STATPROPSTG;
     k : integer;
    
    function PropertyPIDToCaption(const ePID: Cardinal): string;
    begin
     case ePID of
       PID_TITLE:
         Result := 'Title';
       PID_SUBJECT:
         Result := 'Subject';
       PID_AUTHOR:
         Result := 'Author';
       PID_KEYWORDS:
         Result := 'Keywords';
       PID_COMMENTS:
         Result := 'Comments';
       PID_TEMPLATE:
         Result := 'Template';
       PID_LASTAUTHOR:
         Result := 'Last Saved By';
       PID_REVNUMBER:
         Result := 'Revision Number';
       PID_EDITTIME:
         Result := 'Total Editing Time';
       PID_LASTPRINTED:
         Result := 'Last Printed';
       PID_CREATE_DTM:
         Result := 'Create Time/Date';
       PID_LASTSAVE_DTM:
         Result := 'Last Saved Time/Date';
       PID_PAGECOUNT:
         Result := 'Number of Pages';
       PID_WORDCOUNT:
         Result := 'Number of Words';
       PID_CHARCOUNT:
         Result := 'Number of Characters';
       PID_THUMBNAIL:
         Result := 'Thumbnail';
       PID_APPNAME:
         Result := 'Creating Application';
       PID_SECURITY:
         Result := 'Security';
       else
         Result := '$' + IntToHex(ePID, 8);
       end
    end;
    
    begin
     Result := '';
    try
     OleCheck(StgOpenStorageEx(PWideChar(FileName),
     STGM_READ or STGM_SHARE_DENY_WRITE,
     STGFMT_FILE,
     0, nil,  nil, @IID_IPropertySetStorage, stg));
    
     PropSetStg := Stg as IPropertySetStorage;
    
     OleCheck(PropSetStg.Open(FmtID_SummaryInformation,
        STGM_READ or STGM_SHARE_EXCLUSIVE, PropStg));
    
     OleCheck(PropStg.Enum(PropEnum));
     I := 0;
    
     hr := PropEnum.Next(1, PropStat, nil);
      while hr = S_OK do
      begin
        inc(I);
        SetLength(PropSpec,I);
        PropSpec[i-1].ulKind := PRSPEC_PROPID;
        PropSpec[i-1].propid := PropStat.propid;
        hr := PropEnum.Next(1, PropStat, nil);
     end;
    
     SetLength(PropVariant,i);
     Rslt := PropStg.ReadMultiple(i, @PropSpec[0], @PropVariant[0]);
    
     if Rslt =  S_FALSE then Exit;
    
     for k := 0 to i -1 do
      begin
        S := '';
        if PropVariant[k].vt = VT_LPSTR then
          if Assigned(PropVariant[k].pszVal) then
           S := PropVariant[k].pszVal;
    
        S := Format(PropertyPIDToCaption(PropSpec[k].Propid)+ ' %s',[s]);
       if S <> '' then Result := Result + S + #13;
     end;
     finally
     end;
    end;
    

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