placeholder_base = 'w3tc_lazyload_' . md5(
isset( $_SERVER['REQUEST_TIME'] ) ? sanitize_text_field( wp_unslash( $_SERVER['REQUEST_TIME'] ) ) : ''
) . '_';
}
/**
* Replaces unmutable content (e.g., scripts and styles) in the provided buffer with placeholders.
*
* This method identifies `~is',
array( $this, 'placeholder' ),
$buffer
);
// styles.
$buffer = preg_replace_callback(
'~\s*]*)>(.*?)~is',
array( $this, 'placeholder' ),
$buffer
);
return $buffer;
}
/**
* Restores unmutable content in the provided buffer by replacing placeholders with their original content.
*
* This method replaces previously added placeholders with their associated content stored in `$placeholders`.
*
* @param string $buffer The HTML content buffer containing placeholders.
*
* @return string The restored buffer with original unmutable content.
*/
public function restore_unmutable( $buffer ) {
return str_replace(
array_keys( $this->placeholders ),
array_values( $this->placeholders ),
$buffer
);
}
/**
* Generates a unique placeholder for a matched piece of unmutable content and stores it.
*
* This method is called internally by `remove_unmutable` to replace matches (e.g., scripts and styles)
* with unique placeholders. The original content is stored in `$placeholders`.
*
* @param array $matches The matches found by the `preg_replace_callback` function,
* where the full match is at index 0.
*
* @return string The generated placeholder key.
*/
public function placeholder( $matches ) {
$key = '{' . $this->placeholder_base . count( $this->placeholders ) . '}';
$this->placeholders[ $key ] = $matches[0];
return $key;
}
}