Code tidy

- Diff::render() has the same $old==$new check
- AbstractRenderer::getIdenticalResult() would be more flexible than using a constant

Signed-off-by: Jack Cherng <jfcherng@gmail.com>

Author: jfcherng

src/Diff.php

@@ -216,9 +216,9 @@ public function render(AbstractRenderer $renderer): string
 
         // the "no difference" situation may happen frequently
         // let's save some calculation if possible
-        return $this->a !== $this->b
-            ? $renderer->render()
-            : $renderer::IDENTICAL_RESULT;
+        return $this->a === $this->b
+            ? $renderer::getIdenticalResult()
+            : $renderer->render();
     }
 
     /**
@@ -232,10 +232,8 @@ public function render(AbstractRenderer $renderer): string
      */
     private function getText(array $lines, int $start = 0, ?int $end = null): array
     {
-        if ($start === 0 && (!isset($end) || $end === \count($lines))) {
-            return $lines;
-        }
-
-        return \array_slice($lines, $start, isset($end) ? $end - $start : 1);
+        return $start === 0 && (!isset($end) || $end === \count($lines))
+            ? $lines
+            : \array_slice($lines, $start, isset($end) ? $end - $start : 1);
     }
 }

src/DiffHelper.php

@@ -90,12 +90,6 @@ public static function calculate($old, $new, string $template = 'Unified', array
         \is_string($old) && ($old = \explode("\n", $old));
         \is_string($new) && ($new = \explode("\n", $new));
 
-        // the "no difference" situation may happen frequently
-        // let's save some calculation if possible
-        if ($old === $new) {
-            return RendererFactory::resolveTemplate($template)::IDENTICAL_RESULT;
-        }
-
         return Diff::getInstance()
             ->setAB($old, $new)
             ->setOptions($diffOptions)

src/Renderer/AbstractRenderer.php

@@ -24,11 +24,6 @@ abstract class AbstractRenderer implements RendererInterface
      */
     const IS_HTML_TEMPLATE = true;
 
-    /**
-     * @var string the output result when the old and the new are the same
-     */
-    const IDENTICAL_RESULT = '';
-
     /**
      * @var Diff the instance of the diff class that this renderer is generating the rendered diff for
      */
@@ -127,6 +122,16 @@ public function getOptions(): array
         return $this->options;
     }
 
+    /**
+     * Get the renderer result when the old and the new are the same.
+     *
+     * @return string
+     */
+    public static function getIdenticalResult(): string
+    {
+        return '';
+    }
+
     /**
      * Update the Language object.
      *

src/Renderer/Html/Inline.php

@@ -26,7 +26,7 @@ public function render(): string
         $changes = $this->getChanges();
 
         if (empty($changes)) {
-            return self::IDENTICAL_RESULT;
+            return self::getIdenticalResult();
         }
 
         $html = '<table class="diff diff-html diff-inline">';

src/Renderer/Html/Json.php

@@ -23,11 +23,6 @@ final class Json extends AbstractHtml
      */
     const IS_TEXT_TEMPLATE = true;
 
-    /**
-     * {@inheritdoc}
-     */
-    const IDENTICAL_RESULT = '[]';
-
     /**
      * {@inheritdoc}
      */

src/Renderer/Html/SideBySide.php

@@ -26,7 +26,7 @@ public function render(): string
         $changes = $this->getChanges();
 
         if (empty($changes)) {
-            return self::IDENTICAL_RESULT;
+            return self::getIdenticalResult();
         }
 
         $html = '<table class="diff diff-html diff-side-by-side">';