Date: Tue, 08 Feb 2000 09:01:45 -0700
From: Zwirch
Subject: H_MODIFY_OUTPUT
Type: Feature
State: New


From:    Zwirch@PK-Mud
Cc:
Subject: H_MODIFY_OUTPUT-driverhook
Date:    Tue Feb  8 14:15:20 2000

Du kannst das Diff zu LDMud-dev164 im PK-Mud-Ftp ziehen (ftp pk.mud.de 4713,
anonymous login, Software/Driver/diff-dev164-outputhook).
Folgendes macht der Hook:
---------------------------------------------------------------------------
        H_MODIFY_OUTPUT
          Optional hook to modify every output that is send to an
          interactive user (except prompts or binary_message()).

          Hook setting can be an closure or the name of the function
          to call in the object.
=== More: (38%) Page 1, 1..16 [CR,u,f,l,q,/<regexp>,<page>,?]

          If the hook is a closure, it is called as

            string <closure>(string output, object player)

          with the output as first, and the receiving player as
          second argument.

          If the hook is a string, it is used as the name of an lfun
          in the command giving player, which is called as

            string <name>(string output)

          If the result is a string it is the new output, which will be
          sent to the player, otherwise the original output is sent.
----------------------------------------------------------------------
-----
Getestet hab ichs mit dem Hook als string und als unbound-lambda oder
lfun-closure im Master.
Ich hab auch mal Laufzeitfehler im Hook erzeugt bzw. vom Hook selber
Textausgaben gemacht (ergibt too-deep-recursion). Beides hat 
zumindest mal
nicht gecrasht.
                                                        Ciao, Zwirch
PS: ich schick die Diffs auch noch an lars@bearnip
----------diffs-------------
--- ldmud-164/src/comm.c	Sat Dec 18 01:43:46 1999
+++ ldmud-164-outputhook/src/comm.c	Tue Feb  8 12:42:57 2000
@@ -823,6 +823,61 @@
 }
 
 /*-------------------------------------------------------------------------*/
+
+char *
+call_modify_output(char *buff)
+/* Calls the H_MODIFY_OUTPUT-driverhook (if there is one).
+ * Returns an xalloced copy of the modified string or
+ * NULL if there was no hook.
+ * (The inputstring itself cannot be modified)
+ */
+{
+    svalue_t *svp;
+    char *output;
+    
+    svp = NULL;
+    output=NULL;
+
+    if (closure_hook[H_MODIFY_OUTPUT].type == T_CLOSURE)
+    {
+        lambda_t *l;
+
+        l = closure_hook[H_MODIFY_OUTPUT].u.lambda;
+        if (closure_hook[H_MODIFY_OUTPUT].x.closure_type == CLOSURE_LAMBDA)
+            l->ob = command_giver;
+        push_volatile_string(buff);
+        push_object(command_giver);
+        call_lambda(&closure_hook[H_MODIFY_OUTPUT], 2);
+        transfer_svalue(svp = &apply_return_value, inter_sp--);
+        if (!command_giver)
+            return NULL;
+    }    
+    else if (closure_hook[H_MODIFY_OUTPUT].type == T_STRING
+        && !(O_DESTRUCTED & command_giver->flags))
+    {
+        push_volatile_string(buff);
+        svp =
+          sapply(closure_hook[H_MODIFY_OUTPUT].u.string, command_giver, 1);
+        if (!command_giver)
+            return NULL;
+    }
+
+    /* If svp is not NULL, it contains the new, modified output.
+     */
+    if (svp && svp->type == T_STRING) 
+    {
+        output=xalloc(svalue_strlen(svp)+1);
+        if(!output)
+        {
+            error("Out of memory.\n");
+            /* NOTREACHED */
+            return NULL;
+        }
+        strcpy(output, svp->u.string);
+    } 
+    return output;
+} 
+
 void
 add_message (char *fmt, ...)
 
@@ -870,6 +925,7 @@
        * TODO: Actually, it is used just as a flag for flush/non-flush.
        */
     int   old_message_length;  /* accumulated message length so far */
+    char *tmp;
     char *source;              /* Pointer to the final message to add */
     char *end;                 /* One char past the end of .message_buf[] */
     char *dest;                /* First free char in .message_buf[] */
@@ -878,6 +934,7 @@
     object_t      *snooper;  /* Snooper of <ip> */
     int   n;
 
+    tmp=NULL;
     va_start(va, fmt);
 
     /* Test if the command_giver is a real, living, undestructed user,
@@ -950,7 +1007,6 @@
 
         if (!sending_telnet_command)
         {
-
             /* If there's a shadow successfully handling the
              * message, return.
              * This may cause a recursive call to add_message()!.
@@ -959,6 +1015,13 @@
             if (shadow_catch_message(command_giver, source))
                 return;
 
+            /* call the H_MODIFY_OUTPUT-hook
+             * If the hook modified the output we continue with
+             * the modified string
+             */
+            if(tmp=call_modify_output(source))
+                source=tmp;
+
             /* If there's a snooper, send it the new message prepended
              * with a '%'.
              * For interactive snoopers this means a recursion with
@@ -1118,6 +1181,7 @@
                   "%s comm: write EINTR. Message discarded.\n", time_stamp());
                 if (old_message_length)
                     remove_flush_entry(ip);
+                if(tmp) xfree(tmp);
                 return;
 
               case EWOULDBLOCK:
@@ -1125,10 +1189,12 @@
                   "%s comm: write EWOULDBLOCK. Message discarded.\n", time_stamp());
                 if (old_message_length)
                     remove_flush_entry(ip);
+                if(tmp) xfree(tmp);
                 return;
 
               case EMSGSIZE:
                 fprintf(stderr, "%s comm: write EMSGSIZE.\n", time_stamp());
+                if(tmp) xfree(tmp);
                 return;
 
               case EINVAL:
@@ -1158,6 +1224,7 @@
             if (old_message_length)
                 remove_flush_entry(ip);
             ip->do_close = FLAG_DO_CLOSE;
+            if(tmp) xfree(tmp);
             return;
 
         } /* for (retries) */
@@ -1177,7 +1244,8 @@
     } while (*source);
 
     /* --- Final touches --- */
-
+    if(tmp) xfree(tmp);
+  
     ip->message_length = length = dest - ip->message_buf;
 
     /* Update the ring of interactives with pending data */
--- ldmud-164/src/make_func.y	Mon Dec  6 18:41:06 1999
+++ ldmud-164-outputhook/src/make_func.y	Tue Feb  1 15:10:34 2000
@@ -1284,6 +1284,8 @@
         return H_MODIFY_COMMAND_FNAME;
     if ( !strcmp(name, "COMMAND") )
         return H_COMMAND;
+    if ( !strcmp(name, "MODIFY_OUTPUT") )
+        return H_MODIFY_OUTPUT;
     return -1;
 }
 
--- ldmud-164/src/prolang.y	Fri Dec 17 02:05:54 1999
+++ ldmud-164-outputhook/src/prolang.y	Tue Feb  1 14:40:42 2000
@@ -180,7 +180,7 @@
     H_ERQ_STOP:       SH(T_CLOSURE), \
     H_MODIFY_COMMAND_FNAME: SH(T_STRING), \
     H_COMMAND:        SH(T_CLOSURE) SH(T_STRING), \
-
+    H_MODIFY_OUTPUT:  SH(T_CLOSURE) SH(T_STRING), \
 #undef SH
 
 /*-------------------------------------------------------------------------*/
--- ldmud-164/mudlib/sys/driver_hook.h	Tue Sep 28 23:11:40 1999
+++ ldmud-164-outputhook/mudlib/sys/driver_hook.h	Tue Feb  1 14:39:25 2000
@@ -22,8 +22,9 @@
 #define H_ERQ_STOP              15
 #define H_MODIFY_COMMAND_FNAME  16
 #define H_COMMAND               17
+#define H_MODIFY_OUTPUT         18
 
-#define NUM_CLOSURE_HOOKS       18  /* Number of hooks */
+#define NUM_CLOSURE_HOOKS       19  /* Number of hooks */
 
 #endif /* _DRIVER_HOOK_ */
 

---------------------------