Commands.h

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// Copyright Epic Games, Inc. All Rights Reserved.
 
#pragma once
 
#include "CoreMinimal.h"
#include "Framework/Commands/UICommandInfo.h"
#include "Framework/Commands/InputBindingManager.h"
 
//
// COMMAND DECLARATION
//
 
#define LOC_DEFINE_REGION
 
SLATE_API void MakeUICommand_InternalUseOnly(FBindingContext* This, TSharedPtr< FUICommandInfo >& OutCommand, const TCHAR* InSubNamespace, const TCHAR* InCommandName, const TCHAR* InCommandNameUnderscoreTooltip, const ANSICHAR* DotCommandName, const TCHAR* FriendlyName, const TCHAR* InDescription, const EUserInterfaceActionType CommandType, const FInputChord& InDefaultChord, const FInputChord& InAlternateDefaultChord = FInputChord());
 
// This macro requires LOCTEXT_NAMESPACE to be defined. If you don't want the command to be placed under a sub namespace, provide "" as the namespace.
#define UI_COMMAND_EXT( BindingContext, OutUICommandInfo, CommandIdName, FriendlyName, InDescription, CommandType, InDefaultChord, ... ) \
    MakeUICommand_InternalUseOnly( BindingContext, OutUICommandInfo, TEXT(LOCTEXT_NAMESPACE), TEXT(CommandIdName), TEXT(CommandIdName) TEXT("_ToolTip"), "." CommandIdName, TEXT(FriendlyName), TEXT(InDescription), CommandType, InDefaultChord, ## __VA_ARGS__ );
 
#define UI_COMMAND( CommandId, FriendlyName, InDescription, CommandType, InDefaultChord, ... ) \
    MakeUICommand_InternalUseOnly( this, CommandId, TEXT(LOCTEXT_NAMESPACE), TEXT(#CommandId), TEXT(#CommandId) TEXT("_ToolTip"), "." #CommandId, TEXT(FriendlyName), TEXT(InDescription), CommandType, InDefaultChord, ## __VA_ARGS__ );
 
#undef LOC_DEFINE_REGION
 
#define UE_DECLARE_TCOMMANDS(Type, Api) template<> Api TWeakPtr<Type>& TCommands<Type>::GetInstance();
#define UE_DEFINE_TCOMMANDS(Type) template<> TWeakPtr<Type>& TCommands<Type>::GetInstance() { static TWeakPtr<Type> Inst; return Inst; }
 
template<typename CommandContextType>
class TCommands : public FBindingContext
{
public:
    
 
    inline static void Register()
    {
        TWeakPtr<CommandContextType>& Instance = GetInstance();
        if ( !Instance.IsValid() )
        {
            // We store the singleton instances in the FInputBindingManager in order to prevent
            // different modules from instantiating their own version of TCommands<CommandContextType>.
            TSharedRef<CommandContextType> NewInstance = MakeShareable( new CommandContextType() );
 
            TSharedPtr<FBindingContext> ExistingBindingContext = FInputBindingManager::Get().GetContextByName( NewInstance->GetContextName() );
            if (ExistingBindingContext.IsValid())
            {
                // Someone already made this set of commands, and registered it.
                Instance = StaticCastSharedPtr<CommandContextType>(ExistingBindingContext);
            }
            else
            {
                // Make a new set of commands and register it.
                Instance = NewInstance;
 
                // Registering the first command will add the NewInstance into the Binding Manager, who holds on to it.
                NewInstance->RegisterCommands();
 
                // Notify that new commands have been registered
                CommandsChanged.Broadcast(*NewInstance);
            }
        }
    }
 
    inline static bool IsRegistered()
    {
        return GetInstance().IsValid();
    }
 
    inline static CommandContextType& Get()
    {
        // If you get a crash here, then either your commands object wasn't registered, or it was not kept
        //  alive. The latter could happen if your RegisterCommands() function does not actually register 
        //  any FUICommandInfo objects that use your TCommands object, so nothing keeps it alive.
        return *( GetInstance().Pin() );
    }
 
    inline static void Unregister()
    {
        TWeakPtr<CommandContextType>& Instance = GetInstance();
        // The instance may not be valid if it was never used.
        if( Instance.IsValid() )
        {
            auto InstancePtr = Instance.Pin();
            FInputBindingManager::Get().RemoveContextByName(InstancePtr->GetContextName());
            
            // Notify that new commands have been unregistered
            CommandsChanged.Broadcast(*InstancePtr);
 
            check(InstancePtr.IsUnique());
            InstancePtr.Reset();
        }
    }
 
    inline static const FBindingContext& GetContext()
    {
        TWeakPtr<CommandContextType>& Instance = GetInstance();
        check( Instance.IsValid() );
        return *(Instance.Pin());
    }
    
protected:
    
    TCommands( const FName InContextName, const FText& InContextDesc, const FName InContextParent, const FName InStyleSetName )
        : FBindingContext( InContextName, InContextDesc, InContextParent, InStyleSetName )
    {
    }
    virtual ~TCommands()
    {
    }
 
#if PLATFORM_UNIX || PLATFORM_APPLE
    static SLATE_API TWeakPtr<CommandContextType>& GetInstance()
    {
        static TWeakPtr<CommandContextType> Inst;
        return Inst;
    }
#else
    static TWeakPtr<CommandContextType>& GetInstance()
    {
        static TWeakPtr<CommandContextType> Inst;
        return Inst;
    }
#endif
 
    virtual void RegisterCommands() = 0;
 
};