1 files changed, 100 insertions, 0 deletions
diff --git a/vendor/open-telemetry/sdk/Trace/Sampler/ParentBased.php b/vendor/open-telemetry/sdk/Trace/Sampler/ParentBased.php
new file mode 100644
index 000000000..db801d3d8
--- /dev/null
+++ b/vendor/open-telemetry/sdk/Trace/Sampler/ParentBased.php
@@ -0,0 +1,100 @@
+<?php
+
+declare(strict_types=1);
+
+namespace OpenTelemetry\SDK\Trace\Sampler;
+
+use OpenTelemetry\Context\ContextInterface;
+use OpenTelemetry\SDK\Common\Attribute\AttributesInterface;
+use OpenTelemetry\SDK\Trace\SamplerInterface;
+use OpenTelemetry\SDK\Trace\SamplingResult;
+use OpenTelemetry\SDK\Trace\Span;
+
+/**
+ * Phan seems to struggle with the variadic arguments in the latest version
+ * @phan-file-suppress PhanParamTooFewUnpack
+ */
+
+/**
+ * This implementation of the SamplerInterface that respects parent context's sampling decision
+ * and delegates for the root span.
+ * Example:
+ * ```
+ * use OpenTelemetry\API\Trace\ParentBased;
+ * use OpenTelemetry\API\Trace\AlwaysOnSampler
+ *
+ * $rootSampler = new AlwaysOnSampler();
+ * $sampler = new ParentBased($rootSampler);
+ * ```
+ */
+class ParentBased implements SamplerInterface
+{
+    private SamplerInterface $root;
+
+    private SamplerInterface $remoteParentSampler;
+
+    private SamplerInterface $remoteParentNotSampler;
+
+    private SamplerInterface $localParentSampler;
+
+    private SamplerInterface $localParentNotSampler;
+
+    /**
+     * ParentBased sampler delegates the sampling decision based on the parent context.
+     *
+     * @param SamplerInterface $root Sampler called for the span with no parent (root span).
+     * @param SamplerInterface|null $remoteParentSampler Sampler called for the span with the remote sampled parent. When null, `AlwaysOnSampler` is used.
+     * @param SamplerInterface|null $remoteParentNotSampler Sampler called for the span with the remote not sampled parent. When null, `AlwaysOffSampler` is used.
+     * @param SamplerInterface|null $localParentSampler Sampler called for the span with local the sampled parent. When null, `AlwaysOnSampler` is used.
+     * @param SamplerInterface|null $localParentNotSampler Sampler called for the span with the local not sampled parent. When null, `AlwaysOffSampler` is used.
+     */
+    public function __construct(
+        SamplerInterface $root,
+        ?SamplerInterface $remoteParentSampler = null,
+        ?SamplerInterface $remoteParentNotSampler = null,
+        ?SamplerInterface $localParentSampler = null,
+        ?SamplerInterface $localParentNotSampler = null
+    ) {
+        $this->root = $root;
+        $this->remoteParentSampler = $remoteParentSampler ?? new AlwaysOnSampler();
+        $this->remoteParentNotSampler = $remoteParentNotSampler ?? new AlwaysOffSampler();
+        $this->localParentSampler = $localParentSampler ?? new AlwaysOnSampler();
+        $this->localParentNotSampler = $localParentNotSampler ?? new AlwaysOffSampler();
+    }
+
+    /**
+     * Invokes the respective delegate sampler when parent is set or uses root sampler for the root span.
+     * {@inheritdoc}
+     */
+    public function shouldSample(
+        ContextInterface $parentContext,
+        string $traceId,
+        string $spanName,
+        int $spanKind,
+        AttributesInterface $attributes,
+        array $links
+    ): SamplingResult {
+        $parentSpan = Span::fromContext($parentContext);
+        $parentSpanContext = $parentSpan->getContext();
+
+        // Invalid parent SpanContext indicates root span is being created
+        if (!$parentSpanContext->isValid()) {
+            return $this->root->shouldSample(...func_get_args());
+        }
+
+        if ($parentSpanContext->isRemote()) {
+            return $parentSpanContext->isSampled()
+                ? $this->remoteParentSampler->shouldSample(...func_get_args())
+                : $this->remoteParentNotSampler->shouldSample(...func_get_args());
+        }
+
+        return $parentSpanContext->isSampled()
+            ? $this->localParentSampler->shouldSample(...func_get_args())
+            : $this->localParentNotSampler->shouldSample(...func_get_args());
+    }
+
+    public function getDescription(): string
+    {
+        return 'ParentBased+' . $this->root->getDescription();
+    }
+}