Add ->moveToAsync()

Fixes #29
Will add to the interface in h-h-r-r-i shortly.

Author: lexidor

.hhconfig

@@ -37,5 +37,5 @@ safe_vector_array = true
 typecheck_xhp_cvars = true
 unsafe_rx = false
 allowed_decl_fixme_codes=2053,4047
-allowed_fixme_codes_strict=2011,2049,2050,2053,4026,4027,4047,4053,4104,4107,4108,4110,4128,4135,4188,4200,4240,4248,4323
+allowed_fixme_codes_strict=2011,2049,2050,2053,4026,4027,4047,4053,4104,4107,4108,4110,4128,4135,4188,4200,4240,4248,4323,4390
 ignored_paths = [ "vendor/.+/tests/.+" ]

src/UploadedFile.hack

@@ -10,7 +10,7 @@
 namespace Usox\HackTTP;
 
 use namespace Facebook\Experimental\Http\Message;
-use namespace HH\Lib\{File, IO, Str};
+use namespace HH\Lib\{File, IO};
 
 final class UploadedFile implements Message\UploadedFileInterface {
 
@@ -38,14 +38,22 @@ final class UploadedFile implements Message\UploadedFileInterface {
     }
   }
 
+  /**
+   * @deprecated HH\Asio\join() is bad for performance and could stall forever.
+   */
+  <<__Deprecated('Use moveToAsync instead')>>
   public function moveTo(string $target_path): void {
+    \HH\Asio\join($this->moveToAsync($target_path));
+  }
+
+  public async function moveToAsync(string $target_path): Awaitable<void> {
     $this->validateActive();
-    if (Str\length($target_path) === 0) {
+    if ($target_path === '') {
       throw new \InvalidArgumentException(
         'Invalid path provided for move operation; must be a non-empty string',
       );
     }
-    \HH\Asio\join($this->writeAsync($target_path));
+    await $this->writeAsync($target_path);
 
     $this->moved = true;
   }

tests/UploadedFileTest.hack

@@ -78,7 +78,7 @@ class UploadedFileTest extends HackTest {
       Message\UploadedFileError::ERROR_CANCELED_BY_EXTENSION
     );
 
-    expect(() ==> $file->moveTo('/dev/null'))
+    expect(async () ==> await $file->moveToAsync('/dev/null'))
       ->toThrow(
         \RuntimeException::class,
         'Cannot retrieve stream due to upload error',
@@ -97,7 +97,7 @@ class UploadedFileTest extends HackTest {
       666
     );
 
-    $file->moveTo($filename);
+    await $file->moveToAsync($filename);
     $ex = expect(() ==> $read_handle->close())->toThrow(
       OS\ErrnoException::class,
     );
@@ -110,7 +110,7 @@ class UploadedFileTest extends HackTest {
 
     // after moving the file, the readhandle becomes invalid
 
-    expect(() ==> $file->moveTo('/dev/null'))
+    expect(async () ==> await $file->moveToAsync('/dev/null'))
       ->toThrow(
         \RuntimeException::class,
         'Cannot retrieve stream after it has already been moved',