When I run the prog below, the result value of the stgOpenStorage is STG_E_SHAREVIOLATION. How should I close the IStorage to get it unlocked?

procedure TForm1.btnSaveClick(Sender: TObject);
var
  fileName : string;
  streamName : string;

  procedure storeTextIntoStorageStream( text_ : string );
  var
    documentStorage : IStorage;
    levelIStream : IStream;
    i, j : integer;
  begin
    if ( fileExists( fileName ) ) then
      deleteFile( fileName );
    stgCreateDocfile( @fileName[1], STGM_WRITE or STGM_SHARE_EXCLUSIVE or STGM_DIRECT or STGM_CREATE, 0, documentStorage );
    try
      documentStorage.CreateStream( @streamName[1], STGM_WRITE or STGM_SHARE_EXCLUSIVE or STGM_DIRECT, 0, 0, levelIStream );
      try
        i := length( text_ );
        levelIStream.write( @i, sizeOf( integer ), @j );
        levelIStream.write( @text_[1], i*sizeOf( char ), @j );
      finally
        levelIStream.Commit( 0 );
        levelIStream := NIL;
      end;
    finally
      documentStorage.Commit( 0 );
      documentStorage := NIL;
    end;
  end;

  function readTextFromStorageStream : string;
  var
    documentStorage : IStorage;
    levelIStream : IStream;
    i, j : integer;
  begin
    i := stgOpenStorage( @fileName[1], NIL, STGM_READ or STGM_SHARE_EXCLUSIVE or STGM_DIRECT, NIL, 0, documentStorage );
    try
      documentStorage.OpenStream( @streamName[1], NIL, STGM_READ or STGM_SHARE_EXCLUSIVE or STGM_DIRECT, 0, levelIStream );
      try
        levelIStream.read( @i, sizeOf( integer ), @j );
        setLength( result, i );
        levelIStream.read( @result[1], i*sizeOf( char ), @j );
      finally
        levelIStream := NIL;
      end;
    finally
      documentStorage := NIL;
    end;
  end;

begin
  fileName := 'c:\temp\test.stg';
  streamName := 'Stream-0';
  storeTextIntoStorageStream( memo1.Lines.DelimitedText );
  memo1.Lines.DelimitedText := readTextFromStorageStream;
end;

And how could I set the IStorage/IStream default size / size step? Because my test 1.6K byte content stored in 16K.

CodePudding user response：

It is not enough to set the references to NIL. Call the Release methods on the interfaces:

levelIStream.Release;
levelIStream := NIL

documentIStorage.Release;
documentIStorage := NIL