primo commit

libraries/vendor/guzzlehttp/promises/src/EachPromise.php

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+<?php
+
+namespace GuzzleHttp\Promise;
+
+/**
+ * Represents a promise that iterates over many promises and invokes
+ * side-effect functions in the process.
+ */
+class EachPromise implements PromisorInterface
+{
+    private $pending = [];
+
+    private $nextPendingIndex = 0;
+
+    /** @var \Iterator|null */
+    private $iterable;
+
+    /** @var callable|int|null */
+    private $concurrency;
+
+    /** @var callable|null */
+    private $onFulfilled;
+
+    /** @var callable|null */
+    private $onRejected;
+
+    /** @var Promise|null */
+    private $aggregate;
+
+    /** @var bool|null */
+    private $mutex;
+
+    /**
+     * Configuration hash can include the following key value pairs:
+     *
+     * - fulfilled: (callable) Invoked when a promise fulfills. The function
+     *   is invoked with three arguments: the fulfillment value, the index
+     *   position from the iterable list of the promise, and the aggregate
+     *   promise that manages all of the promises. The aggregate promise may
+     *   be resolved from within the callback to short-circuit the promise.
+     * - rejected: (callable) Invoked when a promise is rejected. The
+     *   function is invoked with three arguments: the rejection reason, the
+     *   index position from the iterable list of the promise, and the
+     *   aggregate promise that manages all of the promises. The aggregate
+     *   promise may be resolved from within the callback to short-circuit
+     *   the promise.
+     * - concurrency: (integer) Pass this configuration option to limit the
+     *   allowed number of outstanding concurrently executing promises,
+     *   creating a capped pool of promises. There is no limit by default.
+     *
+     * @param mixed $iterable Promises or values to iterate.
+     * @param array $config   Configuration options
+     */
+    public function __construct($iterable, array $config = [])
+    {
+        $this->iterable = Create::iterFor($iterable);
+
+        if (isset($config['concurrency'])) {
+            $this->concurrency = $config['concurrency'];
+        }
+
+        if (isset($config['fulfilled'])) {
+            $this->onFulfilled = $config['fulfilled'];
+        }
+
+        if (isset($config['rejected'])) {
+            $this->onRejected = $config['rejected'];
+        }
+    }
+
+    /** @psalm-suppress InvalidNullableReturnType */
+    public function promise()
+    {
+        if ($this->aggregate) {
+            return $this->aggregate;
+        }
+
+        try {
+            $this->createPromise();
+            /** @psalm-assert Promise $this->aggregate */
+            $this->iterable->rewind();
+            $this->refillPending();
+        } catch (\Throwable $e) {
+            $this->aggregate->reject($e);
+        } catch (\Exception $e) {
+            $this->aggregate->reject($e);
+        }
+
+        /**
+         * @psalm-suppress NullableReturnStatement
+         * @phpstan-ignore-next-line
+         */
+        return $this->aggregate;
+    }
+
+    private function createPromise()
+    {
+        $this->mutex = false;
+        $this->aggregate = new Promise(function () {
+            if ($this->checkIfFinished()) {
+                return;
+            }
+            reset($this->pending);
+            // Consume a potentially fluctuating list of promises while
+            // ensuring that indexes are maintained (precluding array_shift).
+            while ($promise = current($this->pending)) {
+                next($this->pending);
+                $promise->wait();
+                if (Is::settled($this->aggregate)) {
+                    return;
+                }
+            }
+        });
+
+        // Clear the references when the promise is resolved.
+        $clearFn = function () {
+            $this->iterable = $this->concurrency = $this->pending = null;
+            $this->onFulfilled = $this->onRejected = null;
+            $this->nextPendingIndex = 0;
+        };
+
+        $this->aggregate->then($clearFn, $clearFn);
+    }
+
+    private function refillPending()
+    {
+        if (!$this->concurrency) {
+            // Add all pending promises.
+            while ($this->addPending() && $this->advanceIterator());
+            return;
+        }
+
+        // Add only up to N pending promises.
+        $concurrency = is_callable($this->concurrency)
+            ? call_user_func($this->concurrency, count($this->pending))
+            : $this->concurrency;
+        $concurrency = max($concurrency - count($this->pending), 0);
+        // Concurrency may be set to 0 to disallow new promises.
+        if (!$concurrency) {
+            return;
+        }
+        // Add the first pending promise.
+        $this->addPending();
+        // Note this is special handling for concurrency=1 so that we do
+        // not advance the iterator after adding the first promise. This
+        // helps work around issues with generators that might not have the
+        // next value to yield until promise callbacks are called.
+        while (--$concurrency
+            && $this->advanceIterator()
+            && $this->addPending());
+    }
+
+    private function addPending()
+    {
+        if (!$this->iterable || !$this->iterable->valid()) {
+            return false;
+        }
+
+        $promise = Create::promiseFor($this->iterable->current());
+        $key = $this->iterable->key();
+
+        // Iterable keys may not be unique, so we use a counter to
+        // guarantee uniqueness
+        $idx = $this->nextPendingIndex++;
+
+        $this->pending[$idx] = $promise->then(
+            function ($value) use ($idx, $key) {
+                if ($this->onFulfilled) {
+                    call_user_func(
+                        $this->onFulfilled,
+                        $value,
+                        $key,
+                        $this->aggregate
+                    );
+                }
+                $this->step($idx);
+            },
+            function ($reason) use ($idx, $key) {
+                if ($this->onRejected) {
+                    call_user_func(
+                        $this->onRejected,
+                        $reason,
+                        $key,
+                        $this->aggregate
+                    );
+                }
+                $this->step($idx);
+            }
+        );
+
+        return true;
+    }
+
+    private function advanceIterator()
+    {
+        // Place a lock on the iterator so that we ensure to not recurse,
+        // preventing fatal generator errors.
+        if ($this->mutex) {
+            return false;
+        }
+
+        $this->mutex = true;
+
+        try {
+            $this->iterable->next();
+            $this->mutex = false;
+            return true;
+        } catch (\Throwable $e) {
+            $this->aggregate->reject($e);
+            $this->mutex = false;
+            return false;
+        } catch (\Exception $e) {
+            $this->aggregate->reject($e);
+            $this->mutex = false;
+            return false;
+        }
+    }
+
+    private function step($idx)
+    {
+        // If the promise was already resolved, then ignore this step.
+        if (Is::settled($this->aggregate)) {
+            return;
+        }
+
+        unset($this->pending[$idx]);
+
+        // Only refill pending promises if we are not locked, preventing the
+        // EachPromise to recursively invoke the provided iterator, which
+        // cause a fatal error: "Cannot resume an already running generator"
+        if ($this->advanceIterator() && !$this->checkIfFinished()) {
+            // Add more pending promises if possible.
+            $this->refillPending();
+        }
+    }
+
+    private function checkIfFinished()
+    {
+        if (!$this->pending && !$this->iterable->valid()) {
+            // Resolve the promise if there's nothing left to do.
+            $this->aggregate->resolve(null);
+            return true;
+        }
+
+        return false;
+    }
+}