patch: javap does not show SourceDebugExtension properly

[Jonathan Gibbons]

Dmytro,

Thank you for your suggestion.  Can you provide more details on why the 
existing code does not work. Presumably you get an exception -- what is 
it?  Alternative, can you provide a sample class file for which the 
existing code does not work, together with info on which version of 
which compiler generated the class file?

I agree that the change to visitSourceDebugExtension is probably desirable.

-- Jon


On 06/25/2013 11:32 AM, Dmytro Sheyko wrote:
> Hello,
>
> I was trying to get SourceDebugExtension for compiled jsp class using javap (1.7.0_25, 1.8.0-ea-b91) and it printed something like:
>
>    SourceFile: "x_jsp.java"
>    SourceDebugExtension: null
>    minor version: 0
>    major version: 50
>
> where expected output is following:
>
>    SourceFile: "x_jsp.java"
>    SourceDebugExtension:
>      SMAP
>      x_jsp.java
>      JSP
>      *S JSP
>      *F
>      + 0 x.jsp
>      x.jsp
>      *L
>      1,3:62
>      4:65,4
>      6,4:70
>      9,4:74
>      *E
>    minor version: 0
>    major version: 50
>
> Getting SourceDebugExtension using JDI works well (i.e. class file is correct).
>
> And I would like to propose a patch to fix this issue. Please review.
>
> diff -r b3458329d060 src/share/classes/com/sun/tools/classfile/SourceDebugExtension_attribute.java
> --- a/src/share/classes/com/sun/tools/classfile/SourceDebugExtension_attribute.java    Mon Jun 24 14:27:32 2013 -0700
> +++ b/src/share/classes/com/sun/tools/classfile/SourceDebugExtension_attribute.java    Tue Jun 25 20:22:06 2013 +0300
> @@ -25,9 +25,8 @@
>   
>   package com.sun.tools.classfile;
>   
> -import java.io.ByteArrayInputStream;
> -import java.io.DataInputStream;
>   import java.io.IOException;
> +import java.nio.charset.Charset;
>   
>   /**
>    * See JVMS, section 4.8.15.
> @@ -38,6 +37,8 @@
>    *  deletion without notice.</b>
>    */
>   public class SourceDebugExtension_attribute extends Attribute {
> +    private static final Charset UTF8 = Charset.forName("UTF-8");
> +
>       SourceDebugExtension_attribute(ClassReader cr, int name_index, int length) throws IOException {
>           super(name_index, length);
>           debug_extension = new byte[attribute_length];
> @@ -55,12 +56,7 @@
>       }
>   
>       public String getValue() {
> -        DataInputStream d  = new DataInputStream(new ByteArrayInputStream(debug_extension));
> -        try {
> -            return d.readUTF();
> -        } catch (IOException e) {
> -            return null;
> -        }
> +        return new String(debug_extension, UTF8);
>       }
>   
>       public <R, D> R accept(Visitor<R, D> visitor, D data) {
> diff -r b3458329d060 src/share/classes/com/sun/tools/javap/AttributeWriter.java
> --- a/src/share/classes/com/sun/tools/javap/AttributeWriter.java    Mon Jun 24 14:27:32 2013 -0700
> +++ b/src/share/classes/com/sun/tools/javap/AttributeWriter.java    Tue Jun 25 20:22:06 2013 +0300
> @@ -511,7 +511,10 @@
>       }
>   
>       public Void visitSourceDebugExtension(SourceDebugExtension_attribute attr, Void ignore) {
> -        println("SourceDebugExtension: " + attr.getValue());
> +        println("SourceDebugExtension:");
> +        indent(+1);
> +        print(attr.getValue());
> +        indent(-1);
>           return null;
>       }
>   
> Regards,
> Dmytro