fixup! add control-c-handler to rsutils

third-party/rsutils/include/rsutils/concurrency/control-c-handler.h

@@ -7,16 +7,24 @@ namespace rsutils {
 namespace concurrency {
 
 
-// A Python Event-like implementation, simplifying condition-variable and mutex access
+// A handler for catching Control-C input from the user
+// 
+// NOTE: only a single instance should be in use: using more than one has undefined behavior
 //
 class control_c_handler
 {
 public:
     control_c_handler();
     ~control_c_handler();
 
+    // Return true if a Control-C happened
     bool was_pressed() const;
 
+    // Make was_pressed() return false
+    void reset();
+
+    // Block until a Control-C happens
+    // If already was_pressed(), the state is cleared and a new Control-C is waited on
     void wait();
 };
 

third-party/rsutils/src/control-c-handler.cpp

@@ -1,75 +1,86 @@
-// License: Apache 2.0. See LICENSE file in root directory.
-// Copyright(c) 2024 Intel Corporation. All Rights Reserved.
-#include <rsutils/concurrency/control-c-handler.h>
-#include <rsutils/concurrency/event.h>
-#include <rsutils/easylogging/easyloggingpp.h>
-
-#include <signal.h>
-
-
-namespace rsutils {
-namespace concurrency {
-
-
-namespace {
-
-event sigint_ev;
-
-
-void handle_signal( int signal )
-{
-    switch( signal )
-    {
-    case SIGINT:
-        sigint_ev.set();
-        break;
-    }
-}
-
-}  // namespace
-
-
-control_c_handler::control_c_handler()
-{
-#ifdef _WIN32
-    signal( SIGINT, handle_signal );
-#else
-    struct sigaction sa;
-    sa.sa_handler = &handle_signal;
-    sa.sa_flags = SA_RESTART;
-    sigfillset( &sa.sa_mask );
-    if( sigaction( SIGINT, &sa, NULL ) == -1 )
-        LOG_ERROR( "Cannot install SIGINT handler" );
-#endif
-}
-
-
-control_c_handler::~control_c_handler()
-{
-#ifdef _WIN32
-    signal( SIGINT, SIG_DFL );
-#else
-    struct sigaction sa;
-    sa.sa_handler = SIG_DFL;
-    sa.sa_flags = SA_RESTART;
-    sigfillset( &sa.sa_mask );
-    if( sigaction( SIGINT, &sa, NULL ) == -1 )
-        LOG_DEBUG( "cannot uninstall SIGINT handler" );
-#endif
-}
-
-
-bool control_c_handler::was_pressed() const
-{
-    return sigint_ev.is_set();
-}
-
-
-void control_c_handler::wait()
-{
-    sigint_ev.clear_and_wait();
-}
-
-
-}  // namespace concurrency
-}  // namespace rsutils
+// License: Apache 2.0. See LICENSE file in root directory.
+// Copyright(c) 2024 Intel Corporation. All Rights Reserved.
+#include <rsutils/concurrency/control-c-handler.h>
+#include <rsutils/concurrency/event.h>
+#include <rsutils/easylogging/easyloggingpp.h>
+
+#include <signal.h>
+#include <atomic>
+
+
+namespace rsutils {
+namespace concurrency {
+
+
+namespace {
+
+event sigint_ev;
+std::atomic_bool in_use( false );
+
+
+void handle_signal( int signal )
+{
+    switch( signal )
+    {
+    case SIGINT:
+        sigint_ev.set();
+        break;
+    }
+}
+
+}  // namespace
+
+
+control_c_handler::control_c_handler()
+{
+    if( in_use.exchange( true ) )
+        throw std::runtime_error( "a Control-C handler is already in effect" );
+#ifdef _WIN32
+    signal( SIGINT, handle_signal );
+#else
+    struct sigaction sa;
+    sa.sa_handler = &handle_signal;
+    sa.sa_flags = SA_RESTART;
+    sigfillset( &sa.sa_mask );
+    if( sigaction( SIGINT, &sa, NULL ) == -1 )
+        LOG_ERROR( "Cannot install SIGINT handler" );
+#endif
+}
+
+
+control_c_handler::~control_c_handler()
+{
+#ifdef _WIN32
+    signal( SIGINT, SIG_DFL );
+#else
+    struct sigaction sa;
+    sa.sa_handler = SIG_DFL;
+    sa.sa_flags = SA_RESTART;
+    sigfillset( &sa.sa_mask );
+    if( sigaction( SIGINT, &sa, NULL ) == -1 )
+        LOG_DEBUG( "cannot uninstall SIGINT handler" );
+#endif
+    in_use = false;
+}
+
+
+bool control_c_handler::was_pressed() const
+{
+    return sigint_ev.is_set();
+}
+
+
+void control_c_handler::reset()
+{
+    sigint_ev.clear();
+}
+
+
+void control_c_handler::wait()
+{
+    sigint_ev.clear_and_wait();
+}
+
+
+}  // namespace concurrency
+}  // namespace rsutils