build/extracted-examples/guides/hack/06-classes/21-object-disposal/TextFile.hack

// WARNING: Contains some auto-generated boilerplate code, see:
// HHVM\UserDocumentation\MarkdownExt\ExtractedCodeBlocks\FilterBase::addBoilerplate

namespace HHVM\UserDocumentation\Guides\Hack\Classes\ObjectDisposal\TextFile;

class TextFile implements \IDisposable {
  private ?int $fileHandle = null;
  private bool $openFlag = false;
  private string $fileName;
  private string $openMode;

  public function __construct(string $fileName, string $openMode) {
    $this->fileHandle = 55; // open file somehow and store handle
    $this->openFlag = true; // file is open
    $this->fileName = $fileName;
    $this->openMode = $openMode;
  }

  public function close(): void {
    if ($this->openFlag === false) {
      return;
    }

    // ... somehow close the file
    $this->fileHandle = null;
    $this->openFlag = false;

    echo "Closed file $this->fileName\n";
  }

  public function __toString(): string {
    return 'fileName: '.
      $this->fileName.
      ', openMode: '.
      $this->openMode.
      ', fileHandle: '.
      (($this->fileHandle === null) ? "null" : $this->fileHandle).
      ', openFlag: '.
      (($this->openFlag) ? "True" : "False");
  }

  public function __dispose(): void {
    echo "Inside __dispose\n";
    $this->close();
  }

  <<__ReturnDisposable>>
  public static function open_TextFile(
    string $fileName,
    string $openMode,
  ): TextFile {
    return new TextFile($fileName, $openMode);
  }

  public function is_same_TextFile(<<__AcceptDisposable>> TextFile $t): bool {
    return $this->fileHandle === $t->fileHandle;
  }

  // other methods, such as read and write
}

<<__EntryPoint>>
function main(): void {
  \init_docs_autoloader();

  using ($f1 = new TextFile("file1.txt", "rw")) {
    //  echo "\$f1 is >" . $f1 . "<\n";  // usage not permitted
    echo "\$f1 is >".$f1->__toString()."<\n";
    // work with the file
    $f1->close(); // close explicitly
    $f1->close(); // try to close again
  } // dispose called here

  using ($f2 = new TextFile("file2.txt", "rw")) {
    echo "\$f2 is >".$f2->__toString()."<\n";
    // work with the file
    // no explicit close
  } // dispose called here

  using ($f3 = TextFile::open_TextFile("file3.txt", "rw")) {
    echo "\$f3 is >".$f3->__toString()."<\n";
    // work with the file
    // no explicit close
  } // dispose called here

  using $f4 = TextFile::open_TextFile("file4.txt", "rw");
  echo "\$f4 is >".$f4->__toString()."<\n";
  using $f5 = new TextFile("file5.txt", "rw");
  echo "\$f5 is >".$f5->__toString()."<\n";
  // work with both files
  // no explicit close
} // dispose called here for both $f4 and $f5