libcamera: signal: Replace object.h inclusion with forward declatation

The signal.h header doesn't need to include object.h. Replace it with a
forward declaration, and instead include object.h in source files that
require it. It can speed up compilation a little bit, but more
importantly avoids unintended dependencies from the Signal class to the
Object class to be added later as the compiler will catch them.

Signed-off-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Reviewed-by: Milan Zamazal <mzamazal@redhat.com>

include/libcamera/base/signal.h

@@ -13,10 +13,11 @@
 #include <vector>
 
 #include <libcamera/base/bound_method.h>
-#include <libcamera/base/object.h>
 
 namespace libcamera {
 
+class Object;
+
 class SignalBase
 {
 public:

src/libcamera/base/bound_method.cpp

@@ -7,6 +7,7 @@
 
 #include <libcamera/base/bound_method.h>
 #include <libcamera/base/message.h>
+#include <libcamera/base/object.h>
 #include <libcamera/base/semaphore.h>
 #include <libcamera/base/thread.h>
 

src/libcamera/base/signal.cpp

@@ -8,6 +8,7 @@
 #include <libcamera/base/signal.h>
 
 #include <libcamera/base/mutex.h>
+#include <libcamera/base/object.h>
 
 /**
  * \file base/signal.h

src/libcamera/base/thread.cpp

@@ -18,6 +18,7 @@
 #include <libcamera/base/log.h>
 #include <libcamera/base/message.h>
 #include <libcamera/base/mutex.h>
+#include <libcamera/base/object.h>
 
 /**
  * \page thread Thread Support

test/event-thread.cpp

@@ -11,6 +11,7 @@
 #include <unistd.h>
 
 #include <libcamera/base/event_notifier.h>
+#include <libcamera/base/object.h>
 #include <libcamera/base/thread.h>
 #include <libcamera/base/timer.h>
 

test/ipa/ipa_interface_test.cpp

@@ -16,6 +16,7 @@
 
 #include <libcamera/base/event_dispatcher.h>
 #include <libcamera/base/event_notifier.h>
+#include <libcamera/base/object.h>
 #include <libcamera/base/thread.h>
 #include <libcamera/base/timer.h>
 

test/message.cpp

@@ -11,6 +11,7 @@
 #include <thread>
 
 #include <libcamera/base/message.h>
+#include <libcamera/base/object.h>
 #include <libcamera/base/thread.h>
 
 #include "test.h"

test/signal-threads.cpp

@@ -10,6 +10,7 @@
 #include <thread>
 
 #include <libcamera/base/message.h>
+#include <libcamera/base/object.h>
 #include <libcamera/base/thread.h>
 #include <libcamera/base/utils.h>
 

test/timer-thread.cpp

@@ -9,6 +9,7 @@
 #include <iostream>
 
 #include <libcamera/base/event_dispatcher.h>
+#include <libcamera/base/object.h>
 #include <libcamera/base/thread.h>
 #include <libcamera/base/timer.h>
 

utils/ipc/generators/libcamera_templates/module_ipa_proxy.h.tmpl

@@ -18,6 +18,7 @@
 #include <libcamera/ipa/ipa_interface.h>
 #include <libcamera/ipa/{{module_name}}_ipa_interface.h>
 
+#include <libcamera/base/object.h>
 #include <libcamera/base/thread.h>
 
 #include "libcamera/internal/control_serializer.h"