108374 - Poor API for wrapping/unwrapping Java/JavaScript objects

Status: RESOLVED INCOMPLETE

(Core Graveyard :: Java: Live Connect, defect)

Description

[Timothy J. Wood]

jsjava.h declares two functions:

JSJ_ConvertJavaObjectToJSValue
JSJ_ConvertJSValueToJavaObject

Despite the mirror nature of the names of these functions, these functions 
are not mirrors.

The first is a wrapper for jsj_ConvertJavaObjectToJSValue which 
CREATES a new JSValue to wrap the Java object.

The second takes an existing JS wrapper and unwraps it to expose the 
Java object is is wrapping.

There is currently NO function to take a JS object and CREATE a wrapper 
Java object (i.e., there is no public wrapper for the private 
jsj_ConvertJSValueToJavaObject function).

Likewise, there is no function for exposing the wrapped Java object in a 
JSValue.

These need implemented so that (for example) one can fully implement 
the Netscape plugin API which requires that you be able to create a Java 
peer to a plugin and set the 'window' field of the netscape.plugin.Plugin 
instance to a netscape.javascript.JSObject that wraps the Window 
containing the plugin.

There are probably other reasons that these should be exposed.

So, my recommendation would be this:

Get rid of the old public function names and instead create new functions 
with names that state what the functions actually do and provide the full 
compliment of functions:

JSJ_CreateJavaWrapperForJSValue
JSJ_GetJSValueFromJavaWrapper

JSJ_CreateJSWrapperForJavaObject
JSJ_GetJavaObjectFromJSWrapper

I'll be working on a patch and will submit it when ready.  Feel free to 
supply comments on this general approach, though.

Comment 1

[Timothy J. Wood]

Ok, so  there are some issues with preserving object identity that may 
make it worthwhile to have 'convert' API in addition to just wrap/unwrap 
API.  Still, there needs to be more public API in this area.

Comment 2

[Timothy J. Wood]

OK, so keeping the same functions is fine (and necessary for preserving object identity, it looks like).  I've updated the comments in jsjava.h to better indicate what the functions should do and updated JSJ_ConvertJSValueToJavaObject() to actually create a netscape.javascript.JSObject wrapper for a JavaScript value if no such wrapper already exists.

Patch to be attached next.

Comment 3

[Timothy J. Wood]

Attachment: Suggested patch

Comment 4

[Phil Schwartau]

Reassigning to Patrick for consideration of this patch - 

Comment 5

[Bob Clary [:bc] (inactive)]

-> default assignee for old netscape assigned bugs.

Comment 6

[Benjamin Smedberg]

Firefox code moved from custom Liveconnect code to the NPAPI/NPRuntime bridge a while back. Mass-closing the bugs in the liveconnect component which are likely invalid. If you believe that this bug is still relevant to modern versions of Firefox, please reopen it and move it the "Core" product, component "Plug-Ins".