class FileResource

FileResourceTest.php in drupal/core/vendor/kriswallsmith/assetic/tests/Assetic/Test/Factory/Resource/FileResourceTest.php

FunctionCallsFormulaLoaderTest.php in drupal/core/vendor/kriswallsmith/assetic/tests/Assetic/Test/Factory/Loader/FunctionCallsFormulaLoaderTest.php

class FileResource implements ResourceInterface {
  private $path;

  /**
   * Constructor.
   *
   * @param string $path The path to a file
   */
  public function __construct($path) {
    $this->path = $path;
  }
  public function isFresh($timestamp) {
    return file_exists($this->path) && filemtime($this->path) <= $timestamp;
  }
  public function getContent() {
    return file_exists($this->path) ? file_get_contents($this->path) : '';
  }
  public function __toString() {
    return $this->path;
  }

}