From a236223eac3f32b1b9eb980fab5e9d74d7d34c34 Mon Sep 17 00:00:00 2001
From: Aaron Piotrowski <aaron@trowski.com>
Date: Fri, 3 Sep 2021 18:00:25 -0500
Subject: [PATCH] Combine Future/Suspension arrays

---
 lib/Internal/EmitSource.php | 56 +++++++++++++++----------------------
 psalm.examples.xml          | 16 -----------
 2 files changed, 22 insertions(+), 50 deletions(-)
 delete mode 100644 psalm.examples.xml

diff --git a/lib/Internal/EmitSource.php b/lib/Internal/EmitSource.php
index 69c36fb..6c2de94 100644
--- a/lib/Internal/EmitSource.php
+++ b/lib/Internal/EmitSource.php
@@ -22,20 +22,17 @@ final class EmitSource
 {
     private bool $completed = false;
 
-    private \Throwable $exception;
+    private ?\Throwable $exception = null;
 
-    /** @var mixed[] */
+    /** @var array<int, mixed> */
     private array $emittedValues = [];
 
-    /** @var [?\Throwable, mixed][] */
+    /** @var array<int, array{?\Throwable, mixed}> */
     private array $sendValues = [];
 
-    /** @var Deferred[] */
+    /** @var array<int, Deferred|Suspension> */
     private array $backPressure = [];
 
-    /** @var Suspension[] */
-    private array $yielding = [];
-
     /** @var Suspension[] */
     private array $waiting = [];
 
@@ -94,21 +91,17 @@ final class EmitSource
         $position = $this->consumePosition++ - 1;
 
         // Relieve backpressure from prior emit.
-        if (isset($this->yielding[$position])) {
-            $suspension = $this->yielding[$position];
-            unset($this->yielding[$position]);
-            if ($exception) {
-                $suspension->throw($exception);
-            } else {
-                $suspension->resume($value);
-            }
-        } elseif (isset($this->backPressure[$position])) {
-            $deferred = $this->backPressure[$position];
+        if (isset($this->backPressure[$position])) {
+            $placeholder = $this->backPressure[$position];
             unset($this->backPressure[$position]);
             if ($exception) {
-                $deferred->error($exception);
+                $placeholder instanceof Suspension
+                    ? $placeholder->throw($exception)
+                    : $placeholder->error($exception);
             } else {
-                $deferred->complete($value);
+                $placeholder instanceof Suspension
+                    ? $placeholder->resume($value)
+                    : $placeholder->complete($value);
             }
         } elseif ($position >= 0) {
             // Send-values are indexed as $this->consumePosition - 1.
@@ -124,7 +117,7 @@ final class EmitSource
         }
 
         if ($this->completed || $this->disposed) {
-            if (isset($this->exception)) {
+            if ($this->exception) {
                 throw $this->exception;
             }
             return null;
@@ -294,7 +287,7 @@ final class EmitSource
         ++$this->emitPosition;
 
         if ($pair === null) {
-            $this->yielding[$position] = $suspension = Loop::createSuspension();
+            $this->backPressure[$position] = $suspension = Loop::createSuspension();
             return $suspension->suspend();
         }
 
@@ -408,27 +401,22 @@ final class EmitSource
      */
     private function resolvePending(): void
     {
-        $backPressure = \array_merge($this->backPressure, $this->yielding);
+        $backPressure = $this->backPressure;
         $waiting = $this->waiting;
 
-        unset($this->waiting, $this->backPressure, $this->yielding);
+        unset($this->waiting, $this->backPressure);
 
         $exception = $this->exception ?? null;
 
         foreach ($backPressure as $placeholder) {
-            if ($placeholder instanceof Deferred) {
-                if ($exception) {
-                    $placeholder->error($this->exception);
-                } else {
-                    $placeholder->complete(null);
-                }
-                continue;
-            }
-
             if ($exception) {
-                $placeholder->throw($exception);
+                $placeholder instanceof Suspension
+                    ? $placeholder->throw($exception)
+                    : $placeholder->error($exception);
             } else {
-                $placeholder->resume(null);
+                $placeholder instanceof Suspension
+                    ? $placeholder->resume(null)
+                    : $placeholder->complete(null);
             }
         }
 
diff --git a/psalm.examples.xml b/psalm.examples.xml
deleted file mode 100644
index 2ac9d74..0000000
--- a/psalm.examples.xml
+++ /dev/null
@@ -1,16 +0,0 @@
-<?xml version="1.0"?>
-<psalm
-        totallyTyped="true"
-        phpVersion="7.0"
-        resolveFromConfigFile="true"
-        xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
-        xmlns="https://getpsalm.org/schema/config"
-        xsi:schemaLocation="https://getpsalm.org/schema/config vendor/vimeo/psalm/config.xsd"
->
-    <projectFiles>
-        <directory name="examples/psalm"/>
-        <ignoreFiles>
-            <directory name="vendor"/>
-        </ignoreFiles>
-    </projectFiles>
-</psalm>