cvar: remove from the hash table when deleting (`unset` command)

Fixes https://gitlab.com/xonotic/darkplaces/-/issues/400

Refactors Cvar_FindVarLink() to return a hash link pointer pointer
instead of a cvar pointer to avoid passing extra pointer pointers.

Signed-off-by: bones_was_here <bones_was_here@xonotic.au>

diff --git a/cvar.c b/cvar.c
index 83bf6f529c1b3d629a776d5c9baf36ed489ab487..10eda39d5783ebbe5a85300c28aaeece42f0801b 100644 (file)
--- a/cvar.c
+++ b/cvar.c
@@ -74,37 +74,44 @@ cvar_t *Cvar_FindVarAfter(cvar_state_t *cvars, const char *prev_var_name, int ne
        return var;
 }
 
-static cvar_t *Cvar_FindVarLink(cvar_state_t *cvars, const char *var_name, cvar_t **parent, cvar_t ***link, cvar_t **prev_alpha, int neededflags)
+/**
+ * Returns a pointer to the pointer stored in hashtable[] (or the one it links to)
+ * because we'll need to update that when deleting a cvar as other cvar(s) may share its hashindex.
+ */
+static cvar_hash_t **Cvar_FindVarLink(cvar_state_t *cvars, const char *var_name, cvar_t **parent, cvar_t ***link, cvar_t **prev_alpha, int neededflags)
 {
        int hashindex;
-       cvar_hash_t *hash;
+       cvar_t *cvar;
+       cvar_hash_t **hashlinkptr;
 
        // use hash lookup to minimize search time
        hashindex = CRC_Block((const unsigned char *)var_name, strlen(var_name)) % CVAR_HASHSIZE;
        if(parent) *parent = NULL;
        if(prev_alpha) *prev_alpha = NULL;
        if(link) *link = &cvars->hashtable[hashindex]->cvar;
-       for (hash = cvars->hashtable[hashindex];hash;hash = hash->next)
+       hashlinkptr = &cvars->hashtable[hashindex];
+       for (hashlinkptr = &cvars->hashtable[hashindex]; *hashlinkptr; hashlinkptr = &(*hashlinkptr)->next)
        {
-               if (!strcmp (var_name, hash->cvar->name) && (hash->cvar->flags & neededflags))
+               cvar = (*hashlinkptr)->cvar;
+               if (!strcmp (var_name, cvar->name) && (cvar->flags & neededflags))
                        goto match;
                else
-                       for (char **alias = hash->cvar->aliases; alias && *alias; alias++)
-                               if (!strcmp (var_name, *alias) && (hash->cvar->flags & neededflags))
+                       for (char **alias = cvar->aliases; alias && *alias; alias++)
+                               if (!strcmp (var_name, *alias) && (cvar->flags & neededflags))
                                        goto match;
-               if(parent) *parent = hash->cvar;
+               if(parent) *parent = cvar;
        }
        return NULL;
 match:
-       if(!prev_alpha || hash->cvar == cvars->vars)
-               return hash->cvar;
+       if(!prev_alpha || cvar == cvars->vars)
+               return hashlinkptr;
 
        *prev_alpha = cvars->vars;
        // if prev_alpha happens to become NULL then there has been some inconsistency elsewhere
        // already - should I still insert '*prev_alpha &&' in the loop?
-       while((*prev_alpha)->next != hash->cvar)
+       while((*prev_alpha)->next != cvar)
                *prev_alpha = (*prev_alpha)->next;
-       return hash->cvar;
+       return hashlinkptr;
 }
 
 /*
@@ -1095,10 +1102,10 @@ void Cvar_SetA_f(cmd_state_t *cmd)
 void Cvar_Del_f(cmd_state_t *cmd)
 {
        cvar_state_t *cvars = cmd->cvars;
-       int neededflags = ~0;
        int i;
        cvar_t *parent, **link;
        cvar_t *cvar, *prev;
+       cvar_hash_t **hashlinkptr, *oldhashlink;
 
        if(Cmd_Argc(cmd) < 2)
        {
@@ -1107,20 +1114,23 @@ void Cvar_Del_f(cmd_state_t *cmd)
        }
        for(i = 1; i < Cmd_Argc(cmd); ++i)
        {
-               cvar = Cvar_FindVarLink(cvars, Cmd_Argv(cmd, i), &parent, &link, &prev, neededflags);
+               hashlinkptr = Cvar_FindVarLink(cvars, Cmd_Argv(cmd, i), &parent, &link, &prev, ~0);
 
-               if(!cvar)
+               if(!hashlinkptr)
                {
                        Con_Printf("%s: %s is not defined\n", Cmd_Argv(cmd, 0), Cmd_Argv(cmd, i));
                        continue;
                }
+               cvar = (*hashlinkptr)->cvar;
+
                if(Cvar_Readonly(cvar, Cmd_Argv(cmd, 0)))
                        continue;
                if(!(cvar->flags & CF_ALLOCATED))
                {
-                       Con_Printf("%s: %s is static and cannot be deleted\n", Cmd_Argv(cmd, 0), cvar->name);
+                       Con_Printf(CON_WARN "%s: %s is static and cannot be deleted\n", Cmd_Argv(cmd, 0), cvar->name);
                        continue;
                }
+
                if(cvar == cvars->vars)
                {
                        cvars->vars = cvar->next;
@@ -1143,6 +1153,10 @@ void Cvar_Del_f(cmd_state_t *cmd)
                Z_Free((char *)cvar->string);
                Z_Free((char *)cvar->defstring);
                Z_Free(cvar);
+
+               oldhashlink = *hashlinkptr;
+               *hashlinkptr = (*hashlinkptr)->next;
+               Z_Free(oldhashlink);
        }
 }