refactor(macos): drop the C++ wait helper, keep the minimal GCD fix

The deadlock was caused solely by dispatch_async'ing the permission request onto
the main queue, which never runs when no run loop services it. The fix is just to
delete that bounce and call requestAccessForMediaType: directly on the calling
thread, keeping the original dispatch_semaphore wait.

The earlier ccap_apple_async.h helper (std::mutex/condition_variable) and its unit
test were introduced only to make the path portable-C++-testable, but the file was
macOS-only (portability was moot), the cv-on-the-stack rewrite introduced its own
destroy-after-notify UAF, and the test never exercised ProviderApple::open() -- it
tested the invented helper, not the real code path. GCD's dispatch_semaphore is
simpler and, because the completion block retains the semaphore, has no destroy race.

Removes src/ccap_apple_async.h and tests/test_apple_permission.cpp.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

Author: wysaid

src/ccap_apple_async.h

@@ -11,7 +11,6 @@
 #include "ccap_imp_apple.h"
 #include "ccap_file_reader_apple.h"
 
-#include "ccap_apple_async.h"
 #include "ccap_convert.h"
 #include "ccap_convert_frame.h"
 
@@ -20,7 +19,6 @@
 #import <Foundation/Foundation.h>
 #include <cassert>
 #include <cmath>
-#include <functional>
 
 #if _CCAP_LOG_ENABLED_
 #include <deque>
@@ -257,22 +255,19 @@ - (instancetype)initWithProvider:(ProviderApple*)provider {
 - (BOOL)open {
     AVAuthorizationStatus authStatus = [AVCaptureDevice authorizationStatusForMediaType:AVMediaTypeVideo];
     if (authStatus == AVAuthorizationStatusNotDetermined) {
+        dispatch_semaphore_t sema = dispatch_semaphore_create(0);
         CCAP_NSLOG_I(@"ccap: Waiting for camera access permission...");
-        // Request authorization on the calling thread and block until the system's
-        // completion handler fires. We deliberately do NOT dispatch the request onto the
-        // main queue: requestAccessForMediaType: may be called from any thread and
-        // delivers its completion on an internal queue, so bouncing to the main queue
-        // would deadlock whenever no run loop is servicing it (e.g. a ccap::Provider
-        // opened from a worker thread in a process without a CFRunLoop). See
-        // tests/test_apple_permission.cpp.
-        ccap::runBlockingAsyncRequest([](const std::function<void()>& done) {
-            std::function<void()> notifyDone = done; // outlive the async completion
-            [AVCaptureDevice requestAccessForMediaType:AVMediaTypeVideo
-                                     completionHandler:^(BOOL granted) {
-                                         CCAP_NSLOG_I(@"ccap: Camera access %@", granted ? @"granted" : @"denied");
-                                         notifyDone();
-                                     }];
-        });
+        // Request authorization on the calling thread. requestAccessForMediaType: may be
+        // called from any thread and delivers its completion on an internal queue, so we
+        // do NOT bounce the request onto the main queue: that deadlocks whenever no run
+        // loop is servicing the main queue (e.g. a ccap::Provider opened from a worker
+        // thread in a process without a CFRunLoop, such as a Node.js/Electron addon).
+        [AVCaptureDevice requestAccessForMediaType:AVMediaTypeVideo
+                                 completionHandler:^(BOOL granted) {
+                                     CCAP_NSLOG_I(@"ccap: Camera access %@", granted ? @"granted" : @"denied");
+                                     dispatch_semaphore_signal(sema);
+                                 }];
+        dispatch_semaphore_wait(sema, DISPATCH_TIME_FOREVER);
         authStatus = [AVCaptureDevice authorizationStatusForMediaType:AVMediaTypeVideo];
     }
 

src/ccap_imp_apple.mm

@@ -203,7 +203,6 @@ add_executable(
         test_frame_conversions.cpp
         test_boundary_conditions.cpp
         test_grab_timeout.cpp
-        test_apple_permission.cpp  # macOS camera-permission deadlock regression (empty TU elsewhere)
 )
 
 target_link_libraries(