MAINT-5232: Extract LLInitClass, LLDestroyClass from llui/llui.h

to a new llcommon/llinitdestroyclass.h.
This mechanism is so general -- but has so many related moving parts -- that
(a) it deserves to be in a header file all its own, instead of conflated with
llui.h, and (b) it should be in llcommon where anyone can use it. It has no
dependencies whatsoever on llui or anything viewer-specific.
In this very changeset we changed one #include "llui.h" whose comment admits
that it was only dragged in for LLDestroyClass.

13 files changed, 145 insertions, 90 deletions

diff --git a/indra/llcommon/CMakeLists.txt b/indra/llcommon/CMakeLists.txt
index d2d507d676..de5aa0fde4 100755
--- a/indra/llcommon/CMakeLists.txt
+++ b/indra/llcommon/CMakeLists.txt
@@ -162,6 +162,7 @@ set(llcommon_HEADER_FILES
     llhash.h
     llheartbeat.h
     llindexedvector.h
+    llinitdestroyclass.h
     llinitparam.h
     llinstancetracker.h
     llkeythrottle.h
diff --git a/indra/llcommon/llinitdestroyclass.h b/indra/llcommon/llinitdestroyclass.h
new file mode 100644
index 0000000000..ca5c3f07de
--- /dev/null
+++ b/indra/llcommon/llinitdestroyclass.h
@@ -0,0 +1,134 @@
+/**
+ * @file   llinitdestroyclass.h
+ * @author Nat Goodspeed
+ * @date   2015-05-27
+ * @brief  LLInitClass / LLDestroyClass mechanism
+ *
+ * The LLInitClass template, extracted from llui.h, ensures that control will
+ * reach a static initClass() method. LLDestroyClass does the same for a
+ * static destroyClass() method.
+ *
+ * The distinguishing characteristics of these templates are:
+ *
+ * - All LLInitClass<T>::initClass() methods are triggered by an explicit call
+ *   to LLInitClassList::instance().fireCallbacks(). Presumably this call
+ *   happens sometime after all static objects in the program have been
+ *   initialized. In other words, each LLInitClass<T>::initClass() method
+ *   should be able to make some assumptions about global program state.
+ *
+ * - Similarly, LLDestroyClass<T>::destroyClass() methods are triggered by
+ *   LLDestroyClassList::instance().fireCallbacks(). Again, presumably this
+ *   happens at a well-defined moment in the program's shutdown sequence.
+ *
+ * - The initClass() calls happen in an unspecified sequence. You may not rely
+ *   on the relative ordering of LLInitClass<T>::initClass() versus another
+ *   LLInitClass<U>::initClass() method. If you need such a guarantee, use
+ *   LLSingleton instead and make the dependency explicit.
+ *
+ * - Similarly, LLDestroyClass<T>::destroyClass() may happen either before or
+ *   after LLDestroyClass<U>::destroyClass(). You cannot rely on that order.
+ *
+ * $LicenseInfo:firstyear=2015&license=viewerlgpl$
+ * Copyright (c) 2015, Linden Research, Inc.
+ * $/LicenseInfo$
+ */
+
+#if ! defined(LL_LLINITDESTROYCLASS_H)
+#define LL_LLINITDESTROYCLASS_H
+
+#include "llerror.h"
+#include "llsingleton.h"
+#include <boost/function.hpp>
+#include <boost/signals2/signal.hpp>
+#include <typeinfo>
+
+class LLCallbackRegistry
+{
+public:
+	typedef boost::signals2::signal<void()> callback_signal_t;
+	
+	void registerCallback(const callback_signal_t::slot_type& slot)
+	{
+		mCallbacks.connect(slot);
+	}
+
+	void fireCallbacks()
+	{
+		mCallbacks();
+	}
+
+private:
+	callback_signal_t mCallbacks;
+};
+
+class LLInitClassList : 
+	public LLCallbackRegistry, 
+	public LLSingleton<LLInitClassList>
+{
+	friend class LLSingleton<LLInitClassList>;
+private:
+	LLInitClassList() {}
+};
+
+class LLDestroyClassList : 
+	public LLCallbackRegistry, 
+	public LLSingleton<LLDestroyClassList>
+{
+	friend class LLSingleton<LLDestroyClassList>;
+private:
+	LLDestroyClassList() {}
+};
+
+template<typename T>
+class LLRegisterWith
+{
+public:
+	LLRegisterWith(boost::function<void ()> func)
+	{
+		T::instance().registerCallback(func);
+	}
+
+	// this avoids a MSVC bug where non-referenced static members are "optimized" away
+	// even if their constructors have side effects
+	S32 reference()
+	{
+		S32 dummy;
+		dummy = 0;
+		return dummy;
+	}
+};
+
+template<typename T>
+class LLInitClass
+{
+public:
+	LLInitClass() { sRegister.reference(); }
+
+	static LLRegisterWith<LLInitClassList> sRegister;
+private:
+
+	static void initClass()
+	{
+		LL_ERRS() << "No static initClass() method defined for " << typeid(T).name() << LL_ENDL;
+	}
+};
+
+template<typename T>
+class LLDestroyClass
+{
+public:
+	LLDestroyClass() { sRegister.reference(); }
+
+	static LLRegisterWith<LLDestroyClassList> sRegister;
+private:
+
+	static void destroyClass()
+	{
+		LL_ERRS() << "No static destroyClass() method defined for " << typeid(T).name() << LL_ENDL;
+	}
+};
+
+template <typename T> LLRegisterWith<LLInitClassList> LLInitClass<T>::sRegister(&T::initClass);
+template <typename T> LLRegisterWith<LLDestroyClassList> LLDestroyClass<T>::sRegister(&T::destroyClass);
+
+#endif /* ! defined(LL_LLINITDESTROYCLASS_H) */
diff --git a/indra/llui/llspellcheck.h b/indra/llui/llspellcheck.h
index 4ab80195ea..5ecc9aa110 100755
--- a/indra/llui/llspellcheck.h
+++ b/indra/llui/llspellcheck.h
@@ -29,6 +29,7 @@
 
 #include "llsingleton.h"
 #include "llui.h"
+#include "llinitdestroyclass.h"
 #include <boost/signals2.hpp>
 
 class Hunspell;
diff --git a/indra/llui/llui.h b/indra/llui/llui.h
index c727f75c4f..d7151dbee9 100755
--- a/indra/llui/llui.h
+++ b/indra/llui/llui.h
@@ -344,95 +344,6 @@ private:
 
 // Moved LLLocalClipRect to lllocalcliprect.h
 
-class LLCallbackRegistry
-{
-public:
-	typedef boost::signals2::signal<void()> callback_signal_t;
-	
-	void registerCallback(const callback_signal_t::slot_type& slot)
-	{
-		mCallbacks.connect(slot);
-	}
-
-	void fireCallbacks()
-	{
-		mCallbacks();
-	}
-
-private:
-	callback_signal_t mCallbacks;
-};
-
-class LLInitClassList : 
-	public LLCallbackRegistry, 
-	public LLSingleton<LLInitClassList>
-{
-	friend class LLSingleton<LLInitClassList>;
-private:
-	LLInitClassList() {}
-};
-
-class LLDestroyClassList : 
-	public LLCallbackRegistry, 
-	public LLSingleton<LLDestroyClassList>
-{
-	friend class LLSingleton<LLDestroyClassList>;
-private:
-	LLDestroyClassList() {}
-};
-
-template<typename T>
-class LLRegisterWith
-{
-public:
-	LLRegisterWith(boost::function<void ()> func)
-	{
-		T::instance().registerCallback(func);
-	}
-
-	// this avoids a MSVC bug where non-referenced static members are "optimized" away
-	// even if their constructors have side effects
-	S32 reference()
-	{
-		S32 dummy;
-		dummy = 0;
-		return dummy;
-	}
-};
-
-template<typename T>
-class LLInitClass
-{
-public:
-	LLInitClass() { sRegister.reference(); }
-
-	static LLRegisterWith<LLInitClassList> sRegister;
-private:
-
-	static void initClass()
-	{
-		LL_ERRS() << "No static initClass() method defined for " << typeid(T).name() << LL_ENDL;
-	}
-};
-
-template<typename T>
-class LLDestroyClass
-{
-public:
-	LLDestroyClass() { sRegister.reference(); }
-
-	static LLRegisterWith<LLDestroyClassList> sRegister;
-private:
-
-	static void destroyClass()
-	{
-		LL_ERRS() << "No static destroyClass() method defined for " << typeid(T).name() << LL_ENDL;
-	}
-};
-
-template <typename T> LLRegisterWith<LLInitClassList> LLInitClass<T>::sRegister(&T::initClass);
-template <typename T> LLRegisterWith<LLDestroyClassList> LLDestroyClass<T>::sRegister(&T::destroyClass);
-
 // useful parameter blocks
 struct TimeIntervalParam : public LLInitParam::ChoiceBlock<TimeIntervalParam>
 {
diff --git a/indra/newview/llagentwearables.h b/indra/newview/llagentwearables.h
index 1004482020..7dc23c6402 100755
--- a/indra/newview/llagentwearables.h
+++ b/indra/newview/llagentwearables.h
@@ -38,6 +38,7 @@
 #include "llviewerinventory.h"
 #include "llavatarappearancedefines.h"
 #include "llwearabledata.h"
+#include "llinitdestroyclass.h"
 
 class LLInventoryItem;
 class LLVOAvatarSelf;
diff --git a/indra/newview/llfavoritesbar.h b/indra/newview/llfavoritesbar.h
index a370724947..574617fa63 100755
--- a/indra/newview/llfavoritesbar.h
+++ b/indra/newview/llfavoritesbar.h
@@ -34,6 +34,7 @@
 #include "llinventoryobserver.h"
 #include "llinventorymodel.h"
 #include "llviewerinventory.h"
+#include "llinitdestroyclass.h"
 
 class LLMenuItemCallGL;
 class LLToggleableMenu;
diff --git a/indra/newview/llhints.h b/indra/newview/llhints.h
index ebffe561b9..dd6195a9ce 100755
--- a/indra/newview/llhints.h
+++ b/indra/newview/llhints.h
@@ -29,6 +29,7 @@
 
 #include "llpanel.h"
 #include "llnotifications.h"
+#include "llinitdestroyclass.h"
 
 
 class LLHints :  public LLInitClass<LLHints>
diff --git a/indra/newview/llimview.h b/indra/newview/llimview.h
index f92eff4845..79be6fd9d3 100755
--- a/indra/newview/llimview.h
+++ b/indra/newview/llimview.h
@@ -33,6 +33,7 @@
 
 #include "lllogchat.h"
 #include "llvoicechannel.h"
+#include "llinitdestroyclass.h"
 
 class LLAvatarName;
 class LLFriendObserver;
diff --git a/indra/newview/llnavigationbar.h b/indra/newview/llnavigationbar.h
index 7878bab24e..de12a39547 100755
--- a/indra/newview/llnavigationbar.h
+++ b/indra/newview/llnavigationbar.h
@@ -29,6 +29,7 @@
 
 #include "llpanel.h"
 #include "llbutton.h"
+#include "llinitdestroyclass.h"
 
 class LLLocationInputCtrl;
 class LLMenuGL;
diff --git a/indra/newview/llpaneltopinfobar.h b/indra/newview/llpaneltopinfobar.h
index f37bd9c048..274d70c6f9 100755
--- a/indra/newview/llpaneltopinfobar.h
+++ b/indra/newview/llpaneltopinfobar.h
@@ -28,6 +28,7 @@
 #define LLPANELTOPINFOBAR_H_
 
 #include "llpanel.h"
+#include "llinitdestroyclass.h"
 
 class LLButton;
 class LLTextBox;
diff --git a/indra/newview/llsearchhistory.h b/indra/newview/llsearchhistory.h
index 3309a8fcac..ade81675c2 100755
--- a/indra/newview/llsearchhistory.h
+++ b/indra/newview/llsearchhistory.h
@@ -28,6 +28,7 @@
 #define LL_LLSEARCHHISTORY_H
 
 #include "llsingleton.h"
+#include "llinitdestroyclass.h"
 #include "llui.h"
 
 /**
diff --git a/indra/newview/llsyswellwindow.h b/indra/newview/llsyswellwindow.h
index 71b41476f5..cff3711bb9 100755
--- a/indra/newview/llsyswellwindow.h
+++ b/indra/newview/llsyswellwindow.h
@@ -32,6 +32,7 @@
 #include "llscreenchannel.h"
 #include "llsyswellitem.h"
 #include "lltransientdockablefloater.h"
+#include "llinitdestroyclass.h"
 
 class LLAvatarName;
 class LLChiclet;
diff --git a/indra/newview/llviewerinventory.h b/indra/newview/llviewerinventory.h
index ca92565600..78b61d4fbc 100755
--- a/indra/newview/llviewerinventory.h
+++ b/indra/newview/llviewerinventory.h
@@ -30,7 +30,7 @@
 #include "llinventory.h"
 #include "llframetimer.h"
 #include "llwearable.h"
-#include "llui.h" //for LLDestroyClass
+#include "llinitdestroyclass.h" //for LLDestroyClass
 
 #include <boost/signals2.hpp>	// boost::signals2::trackable