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Message-ID: <64F0D442-F781-4895-BAD4-9ED74DF96E73@saxonica.com>
Date: Mon, 18 Nov 2019 14:55:26 +0000
To: PHP internals <internals@lists.php.net>
Subject: Saxon/C - PHP C++ extension threading issues
From: oneil@saxonica.com (O'Neil Delpratt)

Hi,

Consultancy help:

I have written an PHP 7.X extension to my Saxon/C C++ API. My C++ =
program has an Excelsior JET JNI environment which is created as a =
static variable at the start of the program and released at the end.

The threads are created by the JET Runtime, e.g. GC thread, weak =
reference handler thread, finalizers thread, etc. Initially I thought =
best to create the Jet runtime for each request, but this did not work. =
So I tried to keep the Jet runtime alive for the lifetime of the =
extension, which could be reused between requests.

I create the JET runtime (which has several threads) in the =
PHP_MINIT_FUNCTION(saxonc)

To make sure the clean up of the JET threads happens I have added a =
release method in the MSHUTDOWN_FUNCTION of the PHP extension.

The problem is when I run the PHP extension in the browser it just =
hangs. If I remove the code to manage the JET threads the PHP scripts =
run, but does not kill the JET threads. The only way to kill the =
threads.

How can I manage these resources between requests? Is there a way to =
keep a global variable to the JET resources that maintains the static =
variable from the C++ code between requests?
Somehow I think the management via globals as discussed in your blog: =
http://blog.jpauli.tech/2017-01-12-threads-and-php-html/ is relevant and =
I have tried to follow through with this in some test code to get things =
working, but still not resolved the issue.

Here is snippet of the my C++ code for the PHP extension:

void php_saxonc_initialize(void){

  =20
if(SaxonProcessor::jvmCreatedCPP =3D=3D 0){

   =20
SaxonProcessor::jvmCreatedCPP=3D1;


   =20
SaxonProcessor::sxn_environ=3D (sxnc_environment =
*)malloc(sizeof(sxnc_environment));


   =20
/*
     * First of all, load required component.
     * By the time of JET initialization, all components should be =
loaded.
     */


   =20
SaxonProcessor::sxn_environ->myDllHandle =3D loadDefaultDll ();


   =20
/*
     * Initialize JET run-time.
     * The handle of loaded component is used to retrieve Invocation =
API.
     */

    initDefaultJavaRT=20
(SaxonProcessor::sxn_environ);
=20
   =20
}
}



PHP_MINIT_FUNCTION
(saxon)
{



    php_saxonc_initialize
();


    zend_class_entry ce
;

    INIT_CLASS_ENTRY
(ce, "SaxonProcessor", SaxonProcessor_methods);

   =20
....


In a different approach I tried calling the php_saxonc_initialize() =
method in the 'static PHP_GINIT_FUNCTION(saxon)=E2=80=99 but still did =
not get it to work.

This is linked to this bug issue: https://saxonica.plan.io/issues/2055

Full source code for the PHP extension Saxon/C: =
https://dev.saxonica.com/repos/archive/opensource/latest9.9/hec/Saxon.C.AP=
I/php7_saxon.cpp

=
https://dev.saxonica.com/repos/archive/opensource/latest9.9/hec/Saxon.C.AP=
I/php_saxon.h

I am wondering if someone could assist me and collaborate to resolve it. =
We are willing to pay for the consultancy work.

kind regards,

O'Neil=