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writing extensions best practice, pass an object as parameter

php.internals

Torsten Rosenberger

9 years ago

Hello List

I'm new to C and writing extensions
I hope this ist the right list.

I want to port the PEAR HTML_Template_Sigma Class to an PHP
extension. I startet with the old book 'Building custom PHP Extensions'
found now newer one.

At the moment i have some class functions in my extension as they are in
the PHP Class.

in the PHP Class are some callback functions registert

$this->setCallbackFunction('e', array(&$this, '_htmlentities'));
$this->setCallbackFunction('u', 'urlencode');

the easier callback's to a php function i managed with this code

zval tplFunction;
ZVAL_STRING(&tplFunction,"u");
zval callback;
ZVAL_STRING(&callback,"urlencode");

zend_call_method_with_2_params ( obj,Template_Sigma, NULL,
"setcallbackfunction", NULL, &tplFunction, &callback);

but how can i pass the object from a private method of the PHP extension
class to the  setcallbackfunction as it is down in PHP with

array(&$this, '_htmlentities')

So i try doing some bench :(
Testing with php7.

i call the class constructor from the extension 1000 times and also the
same with the PHP class.

$x = new HTML_Template_Sigma("dir","dir_cache");

so the PHP Class with opcache ist equal faste as my extension.
My goal was to write the class as an extension to get faster.

The last question should I use call_user_function or write this function
in C.

for example
the private methode _jsEscape uses the PHP strtr and the second
parameter is an array so the internal php_strtr_array function is
called. Should I instead call the php_strtr function multiple times ?

Best Regards
Torsten

Adam Baratz

9 years ago

>
> but how can i pass the object from a private method of the PHP extension
>

class to the  setcallbackfunction as it is down in PHP with

>
> array(&$this, '_htmlentities')
>

I usually find reading the source for standard library functions to be
helpful for learning how to do things. array_map could help with capturing
a callable and then doing something with it:
https://github.com/php/php-src/blob/master/ext/standard/array.c#L6005

so the PHP Class with opcache ist equal faste as my extension.

> My goal was to write the class as an extension to get faster.
>

Is the constructor where the bulk of the computation happens? Given that
this is a templating tool, it's probably during render. My guess of what
you'd get out of rewriting in C is greater control over string manipulation
and related memory allocation.

That said, if you're hitting performance issues, I might suggest looking
into another templating tool that's more actively maintained. Extensions
are generally harder to maintain than userland code. If you succeed in
writing a faster version of this tool, this could turn into a "now you have
two problems" situation[1]. If at all possible, it'd be better to let an
existing community solve performance issues for you.

The last question should I use call_user_function or write this function

> in C.
>

Call the internal function directly for less overhead.

Hope this helps!

Adam

---
[1] http://regex.info/blog/2006-09-15/247

Johannes Schlueter

9 years ago

On Wed, 2017-01-18 at 09:17 +0100, Torsten Rosenberger wrote:

> Hello List
>
> I'm new to C and writing extensions
> I hope this ist the right list.
>
> I want to port the PEAR HTML_Template_Sigma Class to an PHP
> extension. I startet with the old book 'Building custom PHP Extensions'
> found now newer one.
>
> At the moment i have some class functions in my extension as they are in
> the PHP Class.
>
> in the PHP Class are some callback functions registert
>
> $this->setCallbackFunction('e', array(&$this, '_htmlentities'));

Using a reference here is useless. Just put $this in the aray.

> $this->setCallbackFunction('u', 'urlencode');
>
> the easier callback's to a php function i managed with this code
>
>
>  zval tplFunction;
>  ZVAL_STRING(&tplFunction,"u");
>  zval callback;
>  ZVAL_STRING(&callback,"urlencode");
>
>  zend_call_method_with_2_params ( obj,Template_Sigma, NULL,
> "setcallbackfunction", NULL, &tplFunction, &callback);
>
>
> but how can i pass the object from a private method of the PHP extension
> class to the  setcallbackfunction as it is down in PHP with
>
> array(&$this, '_htmlentities')
>
>
>
> So i try doing some bench :(
> Testing with php7.
>
> i call the class constructor from the extension 1000 times and also the
> same with the PHP class.
>
> $x = new HTML_Template_Sigma("dir","dir_cache");

I don't fully understand what exactly you want to do. If you want to
pass an array with two values to zend_call_method you have to build the
array (array_init, add_next_index_zval, add_next_index_stringl etc.) and
eventually free this again.

For a private member you of course have to mind the context which is
given as class entry via the second argument to
zend_call_method_with_2_params

If you want to receive a callback from a user see the "f" modifier for
zend_parse_paramters, when storing this you probably have to increase a
reference count on some object. In
https://github.com/php-test-helpers/php-test-helpers/blob/master/test_helpers.c#L396 I did this, while that code might not work in PHP 7.

> so the PHP Class with opcache ist equal faste as my extension.
> My goal was to write the class as an extension to get faster.
>
>
>
>
> The last question should I use call_user_function or write this function
> in C.
>
> for example
> the private methode _jsEscape uses the PHP strtr and the second
> parameter is an array so the internal php_strtr_array function is
> called. Should I instead call the php_strtr function multiple times ?

If the extension primarily is just calling userspace-exported functions
there's not much performance gain to win. If you can do more complex
operations in C there can be some gain, though.

johannes