[8.x] Add File::lines($path) method

src/Illuminate/Filesystem/Filesystem.php

@@ -5,8 +5,10 @@
 use ErrorException;
 use FilesystemIterator;
 use Illuminate\Contracts\Filesystem\FileNotFoundException;
+use Illuminate\Support\LazyCollection;
 use Illuminate\Support\Traits\Macroable;
 use RuntimeException;
+use SplFileObject;
 use Symfony\Component\Filesystem\Filesystem as SymfonyFilesystem;
 use Symfony\Component\Finder\Finder;
 use Symfony\Component\Mime\MimeTypes;
@@ -84,6 +86,33 @@ public function sharedGet($path)
         return $contents;
     }
 
+    /**
+     * Get the contents of a file, one line at a time.
+     *
+     * @param  string  $path
+     * @return \Illuminate\Support\LazyCollection
+     *
+     * @throws \Illuminate\Contracts\Filesystem\FileNotFoundException
+     */
+    public function lines($path)
+    {
+        if (! $this->isFile($path)) {
+            throw new FileNotFoundException(
+                "File does not exist at path {$path}."
+            );
+        }
+
+        return LazyCollection::make(function () use ($path) {
+            $file = new SplFileObject($path);
+
+            $file->setFlags(SplFileObject::DROP_NEW_LINE);
+
+            while (! $file->eof()) {
+                yield $file->fgets();
+            }
+        });
+    }
+
     /**
      * Get the returned value of a file.
      *

tests/Filesystem/FilesystemTest.php

@@ -6,6 +6,7 @@
 use Illuminate\Filesystem\Filesystem;
 use Illuminate\Filesystem\FilesystemManager;
 use Illuminate\Foundation\Application;
+use Illuminate\Support\LazyCollection;
 use Illuminate\Testing\Assert;
 use Mockery as m;
 use PHPUnit\Framework\TestCase;
@@ -56,6 +57,27 @@ public function testPutStoresFiles()
         $this->assertStringEqualsFile(self::$tempDir.'/file.txt', 'Hello World');
     }
 
+    public function testLines()
+    {
+        $path = self::$tempDir.'/file.txt';
+
+        $contents = LazyCollection::times(3)
+            ->map(function ($number) {
+                return "line-{$number}";
+            })
+            ->join("\n");
+
+        file_put_contents($path, $contents);
+
+        $files = new Filesystem;
+        $this->assertInstanceOf(LazyCollection::class, $files->lines($path));
+
+        $this->assertSame(
+            ['line-1', 'line-2', 'line-3'],
+            $files->lines($path)->all()
+        );
+    }
+
     public function testReplaceCreatesFile()
     {
         $tempFile = self::$tempDir.'/file.txt';