1 files changed, 110 insertions, 0 deletions
diff --git a/vendor/open-telemetry/sdk/Metrics/Stream/DeltaStorage.php b/vendor/open-telemetry/sdk/Metrics/Stream/DeltaStorage.php
new file mode 100644
index 000000000..b46a28d65
--- /dev/null
+++ b/vendor/open-telemetry/sdk/Metrics/Stream/DeltaStorage.php
@@ -0,0 +1,110 @@
+<?php
+
+declare(strict_types=1);
+
+namespace OpenTelemetry\SDK\Metrics\Stream;
+
+use function assert;
+use GMP;
+use OpenTelemetry\SDK\Metrics\AggregationInterface;
+
+/**
+ * @internal
+ */
+final class DeltaStorage
+{
+    private AggregationInterface $aggregation;
+    private Delta $head;
+
+    public function __construct(AggregationInterface $aggregation)
+    {
+        $this->aggregation = $aggregation;
+        $this->head = new Delta(new Metric([], [], 0), 0);
+
+        /** @phan-suppress-next-line PhanTypeObjectUnsetDeclaredProperty */
+        unset($this->head->metric);
+    }
+
+    /**
+     * @psalm-suppress UndefinedDocblockClass
+     * @phan-suppress PhanUndeclaredTypeParameter
+     * @param int|GMP $readers
+     */
+    public function add(Metric $metric, $readers): void
+    {
+        /** @phpstan-ignore-next-line */
+        if ($readers == 0) {
+            return;
+        }
+
+        if (($this->head->prev->readers ?? null) != $readers) {
+            $this->head->prev = new Delta($metric, $readers, $this->head->prev);
+        } else {
+            assert($this->head->prev !== null);
+            $this->mergeInto($this->head->prev->metric, $metric);
+        }
+    }
+
+    public function collect(int $reader, bool $retain = false): ?Metric
+    {
+        $n = null;
+        for ($d = $this->head; $d->prev; $d = $d->prev) {
+            if (($d->prev->readers >> $reader & 1) != 0) {
+                if ($n !== null) {
+                    assert($n->prev !== null);
+                    $n->prev->readers ^= $d->prev->readers;
+                    $this->mergeInto($d->prev->metric, $n->prev->metric);
+                    $this->tryUnlink($n);
+
+                    if ($n->prev === $d->prev) {
+                        continue;
+                    }
+                }
+
+                $n = $d;
+            }
+        }
+
+        $metric = $n->prev->metric ?? null;
+
+        if (!$retain && $n) {
+            assert($n->prev !== null);
+            $n->prev->readers ^= ($n->prev->readers & 1 | 1) << $reader;
+            $this->tryUnlink($n);
+        }
+
+        return $metric;
+    }
+
+    private function tryUnlink(Delta $n): void
+    {
+        assert($n->prev !== null);
+        /** @phpstan-ignore-next-line */
+        if ($n->prev->readers == 0) {
+            $n->prev = $n->prev->prev;
+
+            return;
+        }
+
+        for ($c = $n->prev->prev;
+             $c && ($n->prev->readers & $c->readers) == 0;
+             $c = $c->prev) {
+        }
+
+        if ($c && $n->prev->readers === $c->readers) {
+            $this->mergeInto($c->metric, $n->prev->metric);
+            $n->prev = $n->prev->prev;
+        }
+    }
+
+    private function mergeInto(Metric $into, Metric $metric): void
+    {
+        foreach ($metric->summaries as $k => $summary) {
+            $into->attributes[$k] ??= $metric->attributes[$k];
+            $into->summaries[$k] = isset($into->summaries[$k])
+                ? $this->aggregation->merge($into->summaries[$k], $summary)
+                : $summary;
+        }
+        $into->exemplars += $metric->exemplars;
+    }
+}