[PM]

Hello!

Today I've added support for functions which return references. This is almost completly transparent ie. you use SH_DECL_HOOK* normally, then you use SH_ADD_HOOK_* normally, etc.

If you want to use it, you only need to download the newest sourcehook.h from svn.

I've tested it with const and non-const references, many hooks, recalls, even callclasses and META_RESULT_ORIG_RET and META_RESULT_OVERRIDE_RET work (see testrefret.cpp in svn).

There's one special new thing:
If you want to return MRES_IGNORED or MRES_HANDLED from a hook handler for a function returning a reference, you'd have to use RETURN_META_VALUE normally; the return value gets ignored so you can pass in anything, but you usually don't have a spare variable lying around to return. So you can (=should) use RETURN_META_NOREF instead:
RETURN_META_NOREF(MRES_IGNORED, int&); works like RETURN_META_VALUE but returns some garbage which you don't have to care about

If you're interested in how I implemented all this (you might have heard that I was planning a separate SH_DECL_* macro set; luckily I didn't have to go that far), read sourcehook.hxx around line 307. Actually, if you're too lazy to look it up, I'll copy it here:

// How it works: // SH_SETUPCALLS doesn't use plain rettype to store the temporary return values (plugin ret, orig ret, // override ret) anymore; instead, it uses SourceHook::ReferenceCarrier<rettype>::type // this is typedefed to the original rettype normally, but if the rettype is a reference, it's a special class // which stores the reference as a pointer, and implements constructors, operator= and a conversion operator. // special cases were needed for getoverrideret / getorigret; these are implemented through the // SourceHook::MacroRefHelpers structs. // Furthermore, SetOverrideRet had to be changed a bit; see SourceHook::OverrideFunctor somewhere down in this file.

Anyway, maybe you want to see an example:

    struct MyTest
    {
        int m_Var;
 
        virtual int & Func(int hello)
        {
            m_Var = hello;
            return m_Var;
        }
    };
 
    int &MyPostHook(int a)
    {
        static int m_MyVar_ThreeExclamationMarks = 50;
 
        // increment the orig ret twice
        META_RESULT_ORIG_RET(int&) += 2;
 
        // override with myvar
        RETURN_META_VALUE(MRES_OVERRIDE, m_MyVar_ThreeExclamationMarks);
    }
 
    SH_DECL_HOOK1(MyTest, Func, SH_NOATTRIB, 0, int&, int);
 
    void TheTest()
    {
        MyTest test;
 
        // call through a pointer so that the compiler doesn't remove the virtal function lookup
        MyTest *pTest = &test;
 
        int &hello1 = pTest->Func(100);
        printf("without hook: test.m_Var is %d  --- hello is %d\n", test.m_Var, hello1);
 
        SH_ADD_HOOK_STATICFUNC(MyTest, Func, pTest, MyPostHook, true);
 
        int &hello2 = pTest->Func(100);
        printf("with hook: test.m_Var is %d  --- hello is %d\n", test.m_Var, hello2);
    }

I've just run it and this is the output:

without hook: test.m_Var is 100 --- hello is 100 with hook: test.m_Var is 102 --- hello is 50

So, as you can see, it seems to work!

What still needs to be done:
-- Someone add it to the wiki XD

So, have fun with it!

PS: I'm leaving for vacation for 2 weeks so if something doesn't work, complain here, I'll fix it when I'm back XD (though I've tested it pretty extensively on both MSVC and GCC). Merci.

[BAILOPAN]

Thanks for this addition, PM. Have fun on vacation!

[L. Duke]

Thanks PM!

...now if I could only remember what I was trying to hook that was returning a reference...

PS: nice 1337 karma

[c0ldfyr3]

Vacation again? You bumb :\

Thanks for the update as always =)