Move to static trampolines and type-safe hooks

For some reason the DLL got a tiny little bit bigger again but that's
fine. This will make orig_ calls more efficient in the inline case, and
also make it harder to screw up and hook the wrong thing by mistake.

Self-explanatory-ish, apart from the fact it's a fairly large API change
of course. And it relies on some more bonkers assembler directive
hackery.

But it works!

The only complaint one might have is that the featsetup functions no
longer take an explicit string which occasionally yields slightly less
perfect error messages, but I've decided this isn't really a problem and
makes the API nicer to use. It's a tradeoff, innit.

1 files changed, 11 insertions, 15 deletions

diff --git a/src/fov.c b/src/fov.c
index b7a278c..07e9367 100644
--- a/src/fov.c
+++ b/src/fov.c
@@ -46,26 +46,23 @@ DEF_CVAR_MINMAX_UNREG(fov_desired,
 static struct con_var *real_fov_desired; // engine's if it has it, or ours
 
 typedef void (*VCALLCONV SetDefaultFOV_func)(void *, int);
-static SetDefaultFOV_func orig_SetDefaultFOV;
-static void VCALLCONV hook_SetDefaultFOV(void *this, int fov) {
+DEF_INLINE_HOOK(SetDefaultFOV_func, SetDefaultFOV)
+static void VCALLCONV hookdest_SetDefaultFOV(void *this, int fov) {
 	// disregard server-side clamped value and force our own value instead
 	orig_SetDefaultFOV(this, con_getvari(real_fov_desired));
 }
 
-static bool find_SetDefaultFOV(struct con_cmd *fov) {
-	const uchar *insns = (const uchar *)fov->cb;
+static SetDefaultFOV_func find_SetDefaultFOV(const uchar *insns) {
 	int callcnt = 0;
 	for (const uchar *p = insns; p - insns < 96;) {
 		// The fov command calls 4 functions, one of them virtual. Of the 3
 		// direct calls, SetDefaultFOV() is the third.
 		if (p[0] == X86_CALL && ++callcnt == 3) {
-			orig_SetDefaultFOV = (SetDefaultFOV_func)(p + 5 +
-					mem_loads32(p + 1));
-			return true;
+			return (SetDefaultFOV_func)(p + 5 + mem_loads32(p + 1));
 		}
 		NEXT_INSN(p, "SetDefaultFOV function");
 	}
-	return false;
+	return 0;
 }
 
 // replacement cvar needs to actively set player fov if in a map
@@ -98,16 +95,15 @@ INIT {
 		con_regvar(fov_desired);
 		real_fov_desired = fov_desired;
 	}
-	if_cold (!find_SetDefaultFOV(cmd_fov)) {
+	SetDefaultFOV_func SetDefaultFOV = find_SetDefaultFOV(cmd_fov->cb_insns);
+	if_cold (!SetDefaultFOV) {
 		errmsg_errorx("couldn't find SetDefaultFOV function");
 		return FEAT_INCOMPAT;
 	}
-
-	struct hook_inline_featsetup_ret h = hook_inline_featsetup(
-			(void *)orig_SetDefaultFOV, (void **)&orig_SetDefaultFOV,
-			"SetDefaultFov");
+	struct hook_featsetup_ret_SetDefaultFOV h =
+			hook_featsetup_SetDefaultFOV(SetDefaultFOV);
 	if_cold (h.err) return h.err;
-	hook_inline_commit(h.prologue, (void *)&hook_SetDefaultFOV);
+	hook_commit_SetDefaultFOV(h.hookpos, &hookdest_SetDefaultFOV);
 
 	// we might not be using our cvar but simpler to do this unconditionally
 	fov_desired->cb = &fovcb;
@@ -130,7 +126,7 @@ END {
 		void *player = ent_get(1); // also singleplayer only
 		if (player) orig_SetDefaultFOV(player, 75);
 	}
-	unhook_inline((void *)orig_SetDefaultFOV);
+	unhook_SetDefaultFOV();
 	cmd_fov->base.flags &= ~_CON_NE_DEVONLY;
 }