Implement info method on Hasher

`Illuminate\Contracts\Hashing\Hasher` added `info` method on Laravel 5.6.
This commit implements this method by returning an array of algorithms for the given integrity hash.

Fixes #5

src/Hasher.php

@@ -12,22 +12,33 @@ class Hasher implements HasherContract
     protected $options = [];
 
     /**
-     * @var array
+     * @var string[]
      */
     protected $supportedAlgorithms = [];
 
     /**
      * Constructor.
      *
-     * @param array $supportedAlgorithms
-     * @param array $options
+     * @param string[] $supportedAlgorithms
+     * @param array    $options
      */
     public function __construct(array $supportedAlgorithms, array $options)
     {
         $this->supportedAlgorithms = $supportedAlgorithms;
         $this->options = $options;
     }
 
+    /**
+     * Get information about the given hashed value.
+     *
+     * @param  string  $integrity
+     * @return array
+     */
+    public function info($integrity)
+    {
+        return $this->extractAlgorithms($integrity, $this->options);
+    }
+
     /**
      * Hash the given file.
      *
@@ -72,12 +83,8 @@ public function needsRehash($integrity, array $options = [])
     {
         $options = $this->getOptions($options);
 
-        $algorithms = collect(explode($options['delimiter'], $integrity))
-            ->map(function ($hash) {
-                return head(explode('-', $hash));
-            });
-
-        return $this->getAlgorithms($options) != $algorithms->all();
+        return $this->extractAlgorithms($integrity, $options)
+            != $this->getAlgorithms($options);
     }
 
     /**
@@ -94,8 +101,8 @@ protected function getOptions(array $options)
     /**
      * Get the hashing algorithms from the options.
      *
-     * @param  array  $options
-     * @return array
+     * @param  array    $options
+     * @return string[]
      * @throws \InvalidArgumentException
      */
     protected function getAlgorithms(array $options)
@@ -115,4 +122,18 @@ protected function getAlgorithms(array $options)
 
         return $options['algorithms'];
     }
+
+    /**
+     * Extract the algorithms from the integrity.
+     *
+     * @param  string   $integrity
+     * @param  array    $options
+     * @return string[]
+     */
+    protected function extractAlgorithms($integrity, array $options)
+    {
+        return array_map(function ($hash) {
+            return head(explode('-', $hash));
+        }, explode($options['delimiter'], $integrity));
+    }
 }

tests/HasherTest.php

@@ -6,6 +6,26 @@
 
 class HasherTest extends TestCase
 {
+    /**
+     * @test
+     */
+    public function it_gets_information_about_a_given_integrity()
+    {
+        // arrange
+
+        $this->app['config']->set('sri.delimiter', '_');
+
+        $hasher = $this->app->make(Hasher::class);
+
+        // act
+
+        $info = $hasher->info('sha256-foo_sha384-bar');
+
+        // assert
+
+        $this->assertEquals(['sha256', 'sha384'], $info);
+    }
+
     /**
      * @test
      */