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WordPress

SMTP::parseHelloFields( string $type )

Source
wp-includes/PHPMailer/SMTP.php:944
Parse a reply to HELO/EHLO command to discover server extensions.

Description

In case of HELO, the only parameter that can be discovered is a server name.

Compatibility

WordPress
core
PHP
7.4–8.6-dev
  • 6.7.7
  • 6.8.8
  • 6.9.7
  • 7.0.4
  • 7.1.0

Present in every tracked release (6.7.7 to 7.1.0), and compiles on PHP 7.4 through 8.6-dev.

Parameters

$typestring
HELO or EHLO

Performance profile

How much work a call to SMTP::parseHelloFields() does, and what it touches: the algorithmic scaling, the Zend instruction count per call across PHP versions, the hooks it hands control to, and the core code that calls it. Measured from the compiled opcodes, not a stopwatch, so every number is identical on any machine running the same PHP version, and every function in core is ranked by cost.

Cost class
Trivial

Touches nothing outside its own arguments.

Scaling
Scales with input

The body loops, so the work grows with what you pass in.

Instructions
12–13

Executed per call on PHP 8.5, depending on the branch taken. The body compiles to 55.

Plugin surface
None

Nothing here hands control to plugin code.

Called by
0

Nothing in core calls this; the cost is only what you spend yourself.

What one call costs · 1 distinct outcome

One number would be a lie: the work depends on which branch runs. These are every distinct cost SMTP::parseHelloFields() can have, taken from its control-flow graph on PHP 8.5.

WhenInstructionsCalls it makes
always12–13explode()

Across PHP versions

PHPCompiledExecutedBranchesNotes
8.6-dev5512–1310
8.55512–1310
8.45512–13105 fewer instructions than PHP 8.3
8.36012–1310
8.26012–13101 more instruction than PHP 8.1
8.15912–13101 fewer instruction than PHP 7.4
7.46012–1310

An instruction is not a fixed amount of time, so a matching count is not necessarily the same speed; what it rules out is a difference in the work itself.

Source code

    protected function parseHelloFields($type)    {        $this->server_caps = [];        $lines = explode("\n", $this->helo_rply);         foreach ($lines as $n => $s) {            //First 4 chars contain response code followed by - or space            $s = trim(substr($s, 4));            if (empty($s)) {                continue;            }            $fields = explode(' ', $s);            if (!empty($fields)) {                if (!$n) {                    $name = $type;                    $fields = $fields[0];                } else {                    $name = array_shift($fields);                    switch ($name) {                        case 'SIZE':                            $fields = ($fields ? $fields[0] : 0);                            break;                        case 'AUTH':                            if (!is_array($fields)) {                                $fields = [];                            }                            break;                        default:                            $fields = true;                    }                }                $this->server_caps[$name] = $fields;            }        }    }

Changelog

Unchanged from 6.7.7 through 7.1.0.

  1. 6.7.7
  2. 6.8.8
  3. 6.9.7
  4. 7.0.4
  5. 7.1.0

Signature, return type and hooks compared across 5 parsed releases.

About this page

Parsed data
Generated from the wordpress-develop 7.1.0 tag, from src/wp-includes/PHPMailer/SMTP.php, and regenerated for each WordPress release so it tracks the code rather than a snapshot of it.
Corrections
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