[Summary view] [Print] [Text view]

   1  <?php
   2  
   3  /*
   4   * This file is part of the Symfony package.
   5   *
   6   * (c) Fabien Potencier <[email protected]>
   7   *
   8   * For the full copyright and license information, please view the LICENSE
   9   * file that was distributed with this source code.
  10   */
  11  
  12  namespace Symfony\Component\String;
  13  
  14  /**
  15   * A string whose value is computed lazily by a callback.
  16   *
  17   * @author Nicolas Grekas <[email protected]>
  18   */
  19  class LazyString implements \Stringable, \JsonSerializable
  20  {
  21      private $value;
  22  
  23      /**
  24       * @param callable|array $callback A callable or a [Closure, method] lazy-callable
  25       *
  26       * @return static
  27       */
  28      public static function fromCallable($callback, ...$arguments): self
  29      {
  30          if (!\is_callable($callback) && !(\is_array($callback) && isset($callback[0]) && $callback[0] instanceof \Closure && 2 >= \count($callback))) {
  31              throw new \TypeError(sprintf('Argument 1 passed to "%s()" must be a callable or a [Closure, method] lazy-callable, "%s" given.', __METHOD__, get_debug_type($callback)));
  32          }
  33  
  34          $lazyString = new static();
  35          $lazyString->value = static function () use (&$callback, &$arguments, &$value): string {
  36              if (null !== $arguments) {
  37                  if (!\is_callable($callback)) {
  38                      $callback[0] = $callback[0]();
  39                      $callback[1] = $callback[1] ?? '__invoke';
  40                  }
  41                  $value = $callback(...$arguments);
  42                  $callback = self::getPrettyName($callback);
  43                  $arguments = null;
  44              }
  45  
  46              return $value ?? '';
  47          };
  48  
  49          return $lazyString;
  50      }
  51  
  52      /**
  53       * @param string|int|float|bool|\Stringable $value
  54       *
  55       * @return static
  56       */
  57      public static function fromStringable($value): self
  58      {
  59          if (!self::isStringable($value)) {
  60              throw new \TypeError(sprintf('Argument 1 passed to "%s()" must be a scalar or a stringable object, "%s" given.', __METHOD__, get_debug_type($value)));
  61          }
  62  
  63          if (\is_object($value)) {
  64              return static::fromCallable([$value, '__toString']);
  65          }
  66  
  67          $lazyString = new static();
  68          $lazyString->value = (string) $value;
  69  
  70          return $lazyString;
  71      }
  72  
  73      /**
  74       * Tells whether the provided value can be cast to string.
  75       */
  76      final public static function isStringable($value): bool
  77      {
  78          return \is_string($value) || $value instanceof self || (\is_object($value) ? method_exists($value, '__toString') : is_scalar($value));
  79      }
  80  
  81      /**
  82       * Casts scalars and stringable objects to strings.
  83       *
  84       * @param object|string|int|float|bool $value
  85       *
  86       * @throws \TypeError When the provided value is not stringable
  87       */
  88      final public static function resolve($value): string
  89      {
  90          return $value;
  91      }
  92  
  93      /**
  94       * @return string
  95       */
  96      public function __toString()
  97      {
  98          if (\is_string($this->value)) {
  99              return $this->value;
 100          }
 101  
 102          try {
 103              return $this->value = ($this->value)();
 104          } catch (\Throwable $e) {
 105              if (\TypeError::class === \get_class($e) && __FILE__ === $e->getFile()) {
 106                  $type = explode(', ', $e->getMessage());
 107                  $type = substr(array_pop($type), 0, -\strlen(' returned'));
 108                  $r = new \ReflectionFunction($this->value);
 109                  $callback = $r->getStaticVariables()['callback'];
 110  
 111                  $e = new \TypeError(sprintf('Return value of %s() passed to %s::fromCallable() must be of the type string, %s returned.', $callback, static::class, $type));
 112              }
 113  
 114              if (\PHP_VERSION_ID < 70400) {
 115                  // leverage the ErrorHandler component with graceful fallback when it's not available
 116                  return trigger_error($e, \E_USER_ERROR);
 117              }
 118  
 119              throw $e;
 120          }
 121      }
 122  
 123      public function __sleep(): array
 124      {
 125          $this->__toString();
 126  
 127          return ['value'];
 128      }
 129  
 130      public function jsonSerialize(): string
 131      {
 132          return $this->__toString();
 133      }
 134  
 135      private function __construct()
 136      {
 137      }
 138  
 139      private static function getPrettyName(callable $callback): string
 140      {
 141          if (\is_string($callback)) {
 142              return $callback;
 143          }
 144  
 145          if (\is_array($callback)) {
 146              $class = \is_object($callback[0]) ? get_debug_type($callback[0]) : $callback[0];
 147              $method = $callback[1];
 148          } elseif ($callback instanceof \Closure) {
 149              $r = new \ReflectionFunction($callback);
 150  
 151              if (false !== strpos($r->name, '{closure}') || !$class = $r->getClosureScopeClass()) {
 152                  return $r->name;
 153              }
 154  
 155              $class = $class->name;
 156              $method = $r->name;
 157          } else {
 158              $class = get_debug_type($callback);
 159              $method = '__invoke';
 160          }
 161  
 162          return $class.'::'.$method;
 163      }
 164  }