Issue #3443939 by mfb: Refactor file hashing for code readability

src/Algorithm.php

@@ -98,42 +98,10 @@ enum Algorithm: string implements AlgorithmInterface {
   /**
    * {@inheritdoc}
    */
-  public function hashInit(): \HashContext|string|NULL {
+  public function getStateMachine(): ?StateMachineInterface {
     return match ($this->getMechanism()) {
-      Mechanism::Hash => ($algo = $this->getHashAlgo()) ? hash_init($algo) : NULL,
-      Mechanism::Sodium => function_exists('sodium_crypto_generichash_init') ? sodium_crypto_generichash_init('', $this->getByteLength()) : NULL,
-    };
-  }
-
-  /**
-   * {@inheritdoc}
-   */
-  public function hashUpdate(\HashContext|string &$state, string $data): bool {
-    return match ($this->getMechanism()) {
-      Mechanism::Hash => (function () use (&$state, $data): bool {
-        assert($state instanceof \HashContext);
-        return hash_update($state, $data);
-      })(),
-      Mechanism::Sodium => (function () use (&$state, $data): bool {
-        assert(is_string($state) && '' !== $state && is_string($data) && '' !== $data);
-        return sodium_crypto_generichash_update($state, $data);
-      })(),
-    };
-  }
-
-  /**
-   * {@inheritdoc}
-   */
-  public function hashFinal(\HashContext|string &$state): string {
-    return match ($this->getMechanism()) {
-      Mechanism::Hash => (function () use (&$state): string {
-        assert($state instanceof \HashContext);
-        return hash_final($state);
-      })(),
-      Mechanism::Sodium => (function () use (&$state): string {
-        assert(is_string($state) && '' !== $state);
-        return bin2hex(sodium_crypto_generichash_final($state, $this->getByteLength()));
-      })(),
+      Mechanism::Hash => ($algo = $this->getHashAlgo()) ? new HashStateMachine($algo) : NULL,
+      Mechanism::Sodium => function_exists('sodium_crypto_generichash_init') ? new SodiumStateMachine($this->getByteLength()) : NULL,
     };
   }
 

src/AlgorithmInterface.php

@@ -37,18 +37,8 @@ interface AlgorithmInterface {
   public function getMechanism(): Mechanism;
 
   /**
-   * Initialize a hash for streaming.
+   * Returns a new hashing state machine for this algorithm, or NULL.
    */
-  public function hashInit(): \HashContext|string|NULL;
-
-  /**
-   * Complete the hash.
-   */
-  public function hashUpdate(\HashContext|string &$state, string $data): bool;
-
-  /**
-   * Finalize an incremental hash and return resulting digest.
-   */
-  public function hashFinal(\HashContext|string &$state): string;
+  public function getStateMachine(): ?StateMachineInterface;
 
 }

src/FileHash.php

@@ -200,7 +200,7 @@ class FileHash implements FileHashInterface {
       return;
     }
     foreach ($algorithms as $algorithm) {
-      if ($state = static::getAlgorithm($algorithm)->hashInit()) {
+      if ($state = static::getAlgorithm($algorithm)->getStateMachine()) {
         $states[$algorithm] = $state;
       }
     }
@@ -213,8 +213,8 @@ class FileHash implements FileHashInterface {
         $setFileHashes();
         return;
       }
-      foreach ($states as $algorithm => &$state) {
-        static::getAlgorithm($algorithm)->hashUpdate($state, $data);
+      foreach ($states as $state) {
+        $state->update($data);
       }
     }
     if (!feof($handle)) {
@@ -222,8 +222,8 @@ class FileHash implements FileHashInterface {
       return;
     }
     fclose($handle);
-    foreach ($states as $algorithm => &$state) {
-      $state = static::getAlgorithm($algorithm)->hashFinal($state);
+    foreach ($states as &$state) {
+      $state = $state->final();
     }
     $setFileHashes($states);
   }

src/HashStateMachine.php

+<?php
+
+namespace Drupal\filehash;
+
+/**
+ * State machine for the Hash PHP extension.
+ */
+class HashStateMachine implements StateMachineInterface {
+
+  /**
+   * The hash state.
+   */
+  protected \HashContext $state;
+
+  public function __construct(string $algo) {
+    $this->state = hash_init($algo);
+  }
+
+  /**
+   * {@inheritdoc}
+   */
+  public function update(string $data): void {
+    hash_update($this->state, $data);
+  }
+
+  /**
+   * {@inheritdoc}
+   */
+  public function final(): string {
+    return hash_final($this->state);
+  }
+
+}

src/SodiumStateMachine.php

+<?php
+
+namespace Drupal\filehash;
+
+/**
+ * State machine for the Sodium PHP extension.
+ */
+class SodiumStateMachine implements StateMachineInterface {
+
+  /**
+   * The hash state.
+   *
+   * @var non-empty-string
+   */
+  protected string $state;
+
+  public function __construct(protected int $length) {
+    $this->state = sodium_crypto_generichash_init('', $length);
+  }
+
+  /**
+   * {@inheritdoc}
+   */
+  public function update(string $data): void {
+    sodium_crypto_generichash_update($this->state, $data);
+  }
+
+  /**
+   * {@inheritdoc}
+   */
+  public function final(): string {
+    return bin2hex(sodium_crypto_generichash_final($this->state, $this->length));
+  }
+
+}

src/StateMachineInterface.php

+<?php
+
+namespace Drupal\filehash;
+
+/**
+ * Defines the state machine interface.
+ */
+interface StateMachineInterface {
+
+  /**
+   * Updates the state with some data.
+   */
+  public function update(string $data): void;
+
+  /**
+   * Returns the computed output.
+   */
+  public function final(): string;
+
+}