function test_is_empty()
{
$g = new SimpleGraph();
$this->assertTrue($g->is_empty());
$g->add_resource_triple('http://example.org/subj', 'http://example.org/pred1', 'http://example.org/obj1');
$this->assertFalse($g->is_empty());
}
function get_differences($query_results)
{
$res = $query_results;
$g_before = new SimpleGraph();
$g_after = new SimpleGraph();
$row_count = $res->num_rows();
$node_index = 0;
$diffs = array();
if ($row_count === 0) {
if ($this->_subject) {
$s = $this->_subject;
} else {
$s = "_:s";
}
$g_after = $this->get_data_as_graph($s);
$index = $g_after->get_index();
if (array_key_exists($s, $index)) {
$additions = $index[$s];
} else {
$additions = array();
}
$diffs[$s] = array('additions' => $additions, 'removals' => array());
} else {
$subjects = array();
for ($i = 0; $i < $row_count; $i++) {
$row = $res->row_array($i);
$rowdata = $res->rowdata($i);
if (array_key_exists('_uri', $row)) {
$s = $row['_uri'];
} else {
if ($this->_subject) {
$s = $this->_subject;
} else {
$s = "_:s";
}
}
$subjects[] = $s;
foreach ($this->_data as $field => $field_info) {
if (array_key_exists($field, $row)) {
$p = $this->_rmap[$field];
if ($rowdata[$field]['type'] === 'literal') {
$g_before->add_literal_triple($s, $p, $row[$field], $rowdata[$field]['lang'], $rowdata[$field]['datatype']);
} else {
if ($rowdata[$field]['type'] === 'uri') {
$g_before->add_resource_triple($s, $p, $row[$field]);
} else {
if ($rowdata[$field]['type'] === 'bnode') {
$g_before->add_resource_triple($s, $p, '_:' . $row[$field]);
}
}
}
}
}
}
if (count($subjects) > 0) {
$subjects = array_unique($subjects);
foreach ($subjects as $s) {
$g_after->add_graph($this->get_data_as_graph($s));
}
}
if ($g_after->is_empty()) {
$additions = array();
if ($g_before->is_empty()) {
$removals = array();
} else {
$removals = $g_before->get_index();
}
} else {
if ($g_before->is_empty()) {
$additions = $g_after->get_index();
$removals = array();
} else {
$removals = SimpleGraph::diff($g_before->get_index(), $g_after->get_index());
$additions = SimpleGraph::diff($g_after->get_index(), $g_before->get_index());
}
}
foreach ($subjects as $s) {
$diff = array('additions' => array(), 'removals' => array());
if (array_key_exists($s, $additions)) {
$diff['additions'] = $additions[$s];
}
if (array_key_exists($s, $removals)) {
$diff['removals'] = $removals[$s];
}
$diffs[$s] = $diff;
}
}
return $diffs;
}
