/**
* Finds all @context URLs in the given JSON-LD input.
*
* @param mixed $input the JSON-LD input.
* @param stdClass $urls a map of URLs (url => false/@contexts).
* @param bool $replace true to replace the URLs in the given input with
* the @contexts from the urls map, false not to.
* @param string $base the base URL to resolve relative URLs with.
*/
protected function _findContextUrls($input, $urls, $replace, $base)
{
if (is_array($input)) {
foreach ($input as $e) {
$this->_findContextUrls($e, $urls, $replace, $base);
}
} else {
if (is_object($input)) {
foreach ($input as $k => &$v) {
if ($k !== '@context') {
$this->_findContextUrls($v, $urls, $replace, $base);
continue;
}
// array @context
if (is_array($v)) {
$length = count($v);
for ($i = 0; $i < $length; ++$i) {
if (is_string($v[$i])) {
$url = jsonld_prepend_base($base, $v[$i]);
// replace w/@context if requested
if ($replace) {
$ctx = $urls->{$url};
if (is_array($ctx)) {
// add flattened context
array_splice($v, $i, 1, $ctx);
$i += count($ctx);
$length += count($ctx);
} else {
$v[$i] = $ctx;
}
} else {
if (!property_exists($urls, $url)) {
$urls->{$url} = false;
}
}
}
}
} else {
if (is_string($v)) {
$v = jsonld_prepend_base($base, $v);
// replace w/@context if requested
if ($replace) {
$input->{$k} = $urls->{$v};
} else {
if (!property_exists($urls, $v)) {
$urls->{$v} = false;
}
}
}
}
}
}
}
}
/**
* Prepends a base IRI to the given relative IRI.
*
* @param string $base the base IRI.
* @param string $iri the relative IRI.
*
* @return string the absolute IRI.
*/
protected function _prependBase($base, $iri)
{
return jsonld_prepend_base($base, $iri);
}