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[String] add LazyString to provide generic stringable objects
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Original file line number | Diff line number | Diff line change |
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@@ -0,0 +1,165 @@ | ||
<?php | ||
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/* | ||
* This file is part of the Symfony package. | ||
* | ||
* (c) Fabien Potencier <fabien@symfony.com> | ||
* | ||
* For the full copyright and license information, please view the LICENSE | ||
* file that was distributed with this source code. | ||
*/ | ||
|
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namespace Symfony\Component\String; | ||
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/** | ||
* A string whose value is computed lazily by a callback. | ||
* | ||
* @author Nicolas Grekas <p@tchwork.com> | ||
*/ | ||
class LazyString implements \JsonSerializable | ||
{ | ||
private $value; | ||
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/** | ||
* @param callable|array $callback A callable or a [Closure, method] lazy-callable | ||
* | ||
* @return static | ||
*/ | ||
public static function fromCallable($callback, ...$arguments): self | ||
{ | ||
if (!\is_callable($callback) && !(\is_array($callback) && isset($callback[0]) && $callback[0] instanceof \Closure && 2 >= \count($callback))) { | ||
throw new \TypeError(sprintf('Argument 1 passed to %s() must be a callable or a [Closure, method] lazy-callable, %s given.', __METHOD__, \gettype($callback))); | ||
} | ||
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$lazyString = new static(); | ||
$lazyString->value = static function () use (&$callback, &$arguments, &$value): string { | ||
if (null !== $arguments) { | ||
if (!\is_callable($callback)) { | ||
$callback[0] = $callback[0](); | ||
$callback[1] = $callback[1] ?? '__invoke'; | ||
} | ||
$value = $callback(...$arguments); | ||
$callback = self::getPrettyName($callback); | ||
$arguments = null; | ||
} | ||
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return $value ?? ''; | ||
}; | ||
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return $lazyString; | ||
} | ||
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/** | ||
* @param object|string|int|float|bool $value A scalar or an object that implements the __toString() magic method | ||
* | ||
* @return static | ||
*/ | ||
public static function fromStringable($value): self | ||
{ | ||
if (!self::isStringable($value)) { | ||
throw new \TypeError(sprintf('Argument 1 passed to %s() must be a scalar or an object that implements the __toString() magic method, %s given.', __METHOD__, \is_object($value) ? \get_class($value) : \gettype($value))); | ||
} | ||
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if (\is_object($value)) { | ||
return static::fromCallable([$value, '__toString']); | ||
} | ||
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$lazyString = new static(); | ||
$lazyString->value = (string) $value; | ||
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return $lazyString; | ||
} | ||
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/** | ||
* Tells whether the provided value can be cast to string. | ||
*/ | ||
final public static function isStringable($value): bool | ||
{ | ||
return \is_string($value) || $value instanceof self || (\is_object($value) ? \is_callable([$value, '__toString']) : is_scalar($value)); | ||
} | ||
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/** | ||
* Casts scalars and stringable objects to strings. | ||
* | ||
* @param object|string|int|float|bool $value | ||
* | ||
* @throws \TypeError When the provided value is not stringable | ||
*/ | ||
final public static function resolve($value): string | ||
{ | ||
return $value; | ||
} | ||
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public function __toString() | ||
{ | ||
if (\is_string($this->value)) { | ||
return $this->value; | ||
} | ||
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try { | ||
return $this->value = ($this->value)(); | ||
} catch (\Throwable $e) { | ||
if (\TypeError::class === \get_class($e) && __FILE__ === $e->getFile()) { | ||
$type = explode(', ', $e->getMessage()); | ||
$type = substr(array_pop($type), 0, -\strlen(' returned')); | ||
$r = new \ReflectionFunction($this->value); | ||
$callback = $r->getStaticVariables()['callback']; | ||
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$e = new \TypeError(sprintf('Return value of %s() passed to %s::fromCallable() must be of the type string, %s returned.', $callback, static::class, $type)); | ||
} | ||
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if (\PHP_VERSION_ID < 70400) { | ||
// leverage the ErrorHandler component with graceful fallback when it's not available | ||
return trigger_error($e, E_USER_ERROR); | ||
} | ||
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throw $e; | ||
} | ||
} | ||
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public function __sleep(): array | ||
{ | ||
$this->__toString(); | ||
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return ['value']; | ||
} | ||
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public function jsonSerialize(): string | ||
{ | ||
return $this->__toString(); | ||
} | ||
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private function __construct() | ||
{ | ||
} | ||
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private static function getPrettyName(callable $callback): string | ||
{ | ||
if (\is_string($callback)) { | ||
return $callback; | ||
} | ||
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if (\is_array($callback)) { | ||
$class = \is_object($callback[0]) ? \get_class($callback[0]) : $callback[0]; | ||
$method = $callback[1]; | ||
} elseif ($callback instanceof \Closure) { | ||
$r = new \ReflectionFunction($callback); | ||
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if (false !== strpos($r->name, '{closure}') || !$class = $r->getClosureScopeClass()) { | ||
return $r->name; | ||
} | ||
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$class = $class->name; | ||
$method = $r->name; | ||
} else { | ||
$class = \get_class($callback); | ||
$method = '__invoke'; | ||
} | ||
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if (isset($class[15]) && "\0" === $class[15] && 0 === strpos($class, "class@anonymous\x00")) { | ||
$class = (get_parent_class($class) ?: key(class_implements($class))).'@anonymous'; | ||
} | ||
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return $class.'::'.$method; | ||
} | ||
} |
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Original file line number | Diff line number | Diff line change |
---|---|---|
@@ -0,0 +1,112 @@ | ||
<?php | ||
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/* | ||
* This file is part of the Symfony package. | ||
* | ||
* (c) Fabien Potencier <fabien@symfony.com> | ||
* | ||
* For the full copyright and license information, please view the LICENSE | ||
* file that was distributed with this source code. | ||
*/ | ||
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namespace Symfony\Component\String\Tests; | ||
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use PHPUnit\Framework\TestCase; | ||
use Symfony\Component\ErrorHandler\ErrorHandler; | ||
use Symfony\Component\String\LazyString; | ||
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class LazyStringTest extends TestCase | ||
{ | ||
public function testLazyString() | ||
{ | ||
$count = 0; | ||
$s = LazyString::fromCallable(function () use (&$count) { | ||
return ++$count; | ||
}); | ||
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$this->assertSame(0, $count); | ||
$this->assertSame('1', (string) $s); | ||
$this->assertSame(1, $count); | ||
} | ||
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public function testLazyCallable() | ||
{ | ||
$count = 0; | ||
$s = LazyString::fromCallable([function () use (&$count) { | ||
return new class($count) { | ||
private $count; | ||
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public function __construct(int &$count) | ||
{ | ||
$this->count = &$count; | ||
} | ||
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public function __invoke() | ||
{ | ||
return ++$this->count; | ||
} | ||
}; | ||
}]); | ||
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$this->assertSame(0, $count); | ||
$this->assertSame('1', (string) $s); | ||
$this->assertSame(1, $count); | ||
$this->assertSame('1', (string) $s); // ensure the value is memoized | ||
$this->assertSame(1, $count); | ||
} | ||
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/** | ||
* @runInSeparateProcess | ||
*/ | ||
public function testReturnTypeError() | ||
{ | ||
ErrorHandler::register(); | ||
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$s = LazyString::fromCallable(function () { return []; }); | ||
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$this->expectException(\TypeError::class); | ||
$this->expectExceptionMessage('Return value of '.__NAMESPACE__.'\{closure}() passed to '.LazyString::class.'::fromCallable() must be of the type string, array returned.'); | ||
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(string) $s; | ||
} | ||
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public function testFromStringable() | ||
{ | ||
$this->assertInstanceOf(LazyString::class, LazyString::fromStringable('abc')); | ||
$this->assertSame('abc', (string) LazyString::fromStringable('abc')); | ||
$this->assertSame('1', (string) LazyString::fromStringable(true)); | ||
$this->assertSame('', (string) LazyString::fromStringable(false)); | ||
$this->assertSame('123', (string) LazyString::fromStringable(123)); | ||
$this->assertSame('123.456', (string) LazyString::fromStringable(123.456)); | ||
$this->assertStringContainsString('hello', (string) LazyString::fromStringable(new \Exception('hello'))); | ||
} | ||
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public function testResolve() | ||
{ | ||
$this->assertSame('abc', LazyString::resolve('abc')); | ||
$this->assertSame('1', LazyString::resolve(true)); | ||
$this->assertSame('', LazyString::resolve(false)); | ||
$this->assertSame('123', LazyString::resolve(123)); | ||
$this->assertSame('123.456', LazyString::resolve(123.456)); | ||
$this->assertStringContainsString('hello', LazyString::resolve(new \Exception('hello'))); | ||
} | ||
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public function testIsStringable() | ||
{ | ||
$this->assertTrue(LazyString::isStringable('abc')); | ||
$this->assertTrue(LazyString::isStringable(true)); | ||
$this->assertTrue(LazyString::isStringable(false)); | ||
$this->assertTrue(LazyString::isStringable(123)); | ||
$this->assertTrue(LazyString::isStringable(123.456)); | ||
$this->assertTrue(LazyString::isStringable(new \Exception('hello'))); | ||
} | ||
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public function testIsNotStringable() | ||
{ | ||
$this->assertFalse(LazyString::isStringable(null)); | ||
$this->assertFalse(LazyString::isStringable([])); | ||
$this->assertFalse(LazyString::isStringable(STDIN)); | ||
$this->assertFalse(LazyString::isStringable(new \StdClass())); | ||
$this->assertFalse(LazyString::isStringable(@eval('return new class() {private function __toString() {}};'))); | ||
} | ||
} |
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