[DOXIATOOLS-45] An incomplete fix for the resource leak bugs in LatexBookRenderer.java

• Type: Bug
• Status: Closed
• Priority: Critical
• Resolution: Auto Closed
• Component/s: Doxia Book Renderer
• Assignee: Unassigned
• Reporter: Guangtai Liang
• Created: 22/Feb/12 06:40
• Updated: 16/Mar/18 22:40
• Resolved: 16/Mar/18 22:40

Description

The fix revision 740164 was aimed to remove resource leak bugs on the FileWriter object "writer"(created in line 204) and the FileReader object "reader" (created in line 219) in the method "writeSection()"of the file " /maven/doxia/doxia/trunk/doxia-book/src/main/java/org/apache/maven/doxia/book/services/renderer/LatexBookRenderer.java" , but it is incomplete.

There are some problems:
1. the LatexBookSink object "sink" is not closed.
2. when the statements at lines 206-215 throw some exception, "writer" will be leaked.

The best way to close such resource objects is putting such close operations for all resource objects in the finaly block of a try-catch-finally structure.

Although a later fix (rev1003021) try to close "sink", the problems still exists in the head revision. The buggy code is copied as bellows ("sink" and "writer" will be leaked when the statements at lines 202-207 throw some exception):

   private SectionInfo writeSection( Section section, BookContext context )
        throws IOException, BookDoxiaException
    {
        File file = new File( context.getOutputDirectory(), ( section.getId() + ".tex" ) );

198        Writer writer = WriterFactory.newWriter( file, context.getOutputEncoding() );

200        LatexBookSink sink = new LatexBookSink( writer );

        BookContext.BookFile bookFile = (BookContext.BookFile) context.getFiles().get( section.getId() );

        if ( bookFile == null )
        {
            throw new BookDoxiaException( "No document that matches section with id="
                        + section.getId() + "." );
        }

        Reader reader = null;
        try
        {
            reader = ReaderFactory.newReader( bookFile.getFile(), context.getInputEncoding() );
            doxia.parse( reader, bookFile.getParserId(), sink );
        }
        catch ( ParserNotFoundException e )
        {
            throw new BookDoxiaException( "Parser not found: "
                        + bookFile.getParserId() + ".", e );
        }
        catch ( ParseException e )
        {
            throw new BookDoxiaException( "Error while parsing document: "
                        + bookFile.getFile().getAbsolutePath() + ".", e );
        }
        catch ( FileNotFoundException e )
        {
            throw new BookDoxiaException( "Could not find document: "
                        + bookFile.getFile().getAbsolutePath() + ".", e );
        }
        finally
        {
233            sink.flush();
234            sink.close();

236            IOUtil.close( reader );
237            IOUtil.close( writer );
        }

        SectionInfo info = new SectionInfo();
        info.id = section.getId();
        info.title = sink.getTitle();

        return info;
    }