diff options
Diffstat (limited to 'src/con_.h')
| -rw-r--r-- | src/con_.h | 60 |
1 files changed, 60 insertions, 0 deletions
@@ -361,6 +361,66 @@ extern struct _con_vtab_iconvar_wrap { #define DEF_CCMD_PLUSMINUS_UNREG DEF_CCMD_PLUSMINUS /* + * Defines a hook function in-place to hook a command callback, factoring in + * different callback ABIs used by different commands and/or different engine + * branches. Defines a hook_##name##_cb function to install the hook and an + * unhook_##name##_cb function to remove it. + * + * The hook function has the implicit arguments argc and argv, just like a + * command handler defined with DEF_CCMD_HERE. Calling the original command + * handler can be done using orig_##name##_cb, passing through argc and argv. + * + * Note that argc and argv MUST remain unmodified, as not all callback + * interfaces pass arguments through the callback and so attempting to change + * these parameters could cause unexpected or inconsistent behaviour across + * engine versions. + * + * In some cases, a command will be defined to take no arguments, in which case + * argc will be zero and argv will be null. In these cases, the parameters + * should still be passed through to the orig_ function, as this ensures + * compatibility with other game/engine versions. + */ +#define DEF_CCMD_COMPAT_HOOK(name) \ + static union { \ + con_cmdcbv1 v1; \ + con_cmdcbv2 v2; \ + } _orig_##name##_cb; \ + static void _orig_##name##_cbv1(int argc, const char *const *argv) { \ + _orig_##name##_cb.v1(); \ + } \ + static void _orig_##name##_cbv2(int argc, const char *const *argv) { \ + struct con_cmdargs args; \ + args.argc = argc; \ + /* XXX: having to copy argv sucks, but can't see how to avoid without + ruining the interface? */ \ + for (int i = 0; i < argc; ++i) args.argv[i] = argv[i]; \ + _orig_##name##_cb.v2(&args); \ + } \ + static void (*orig_##name##_cb)(int argc, const char *const *argv); \ + static void _hook_##name##_cb(int argc, const char *const *argv); \ + static void _hook_##name##_cbv1() { \ + _hook_##name##_cb(0, 0); /* XXX: ??? */ \ + } \ + static void _hook_##name##_cbv2(const struct con_cmdargs *args) { \ + _hook_##name##_cb(args->argc, args->argv); \ + } \ + static void hook_##name##_cb(struct con_cmd *cmd) { \ + _orig_##name##_cb.v1 = cmd->cb_v1; \ + if (cmd->use_newcb) { \ + cmd->cb_v2 = &_hook_##name##_cbv2; \ + orig_##name##_cb = &_orig_##name##_cbv2; \ + } \ + else { \ + cmd->cb_v1 = _hook_##name##_cbv1; \ + orig_##name##_cb = &_orig_##name##_cbv1; \ + } \ + } \ + static void unhook_##name##_cb(struct con_cmd *cmd) { \ + cmd->cb_v1 = _orig_##name##_cb.v1; \ + } \ + static void _hook_##name##_cb(int argc, const char *const *argv) /* ... */ + +/* * These functions register a command or variable, respectively, defined with * the _UNREG variants of the above macros. These can be used to conditionally * register things. Wherever possible, it is advised to use the DEF_FEAT_* |