curses: save/restore message history

Have the curses interface save and restore message history for use
by ^P.  It doesn't spit the saved messages out into the visible
message window after restore; that's too distracting.

doc/fixes36.2

@@ -1,4 +1,4 @@
-$NHDT-Branch: NetHack-3.6.2-beta01 $:$NHDT-Revision: 1.289 $ $NHDT-Date: 1553895318 2019/03/29 21:35:18 $
+$NHDT-Branch: NetHack-3.6.2-beta01 $:$NHDT-Revision: 1.290 $ $NHDT-Date: 1553904170 2019/03/30 00:02:50 $
 
 This fixes36.2 file is here to capture information about updates in the 3.6.x
 lineage following the release of 3.6.1 in April 2018. Please note, however,
@@ -523,6 +523,7 @@ curses: the memory deallocation was releasing previous messages when curses
 curses: popup window to show ^P output was removed from screen but never
 	deleted; further ^P's repeated that cycle; likewise for help which
 	displays an external text file
+curses: preserve ^P message history across save/restore
 vms: add compile of isaac64.c to Makefile.src and vmsbuild.com
 vms+curses: add compile support but it is known to fail to build
 

include/wincurs.h

@@ -222,6 +222,8 @@ extern void curses_init_mesg_history(void);
 extern void curses_teardown_messages(void);
 extern void curses_prev_mesg(void);
 extern void curses_count_window(const char *count_text);
+char *curses_getmsghistory(BOOLEAN_P);
+void curses_putmsghistory(const char *, BOOLEAN_P);
 
 #endif  /* WINCURS_H */
 

win/curses/cursmain.c

@@ -72,8 +72,8 @@ struct window_procs curses_procs = {
     curses_end_screen,
     genl_outrip,
     curses_preference_update,
-    genl_getmsghistory,
-    genl_putmsghistory,
+    curses_getmsghistory,
+    curses_putmsghistory,
     curses_status_init,
     curses_status_finish,
     genl_status_enablefield,

win/curses/cursmesg.c

@@ -693,4 +693,99 @@ get_msg_line(boolean reverse, int mindex)
     return current_mesg;
 }
 
+/* save/restore code retrieves one ^P message at a time during save and
+   puts it into save file; if any new messages are added to the list while
+   that is taking place, the results are likely to be scrambled */
+char *
+curses_getmsghistory(init)
+boolean init;
+{
+    static int nxtidx;
+    nhprev_mesg *mesg;
+
+    if (init)
+        nxtidx = 0;
+    else
+        ++nxtidx;
+
+    if (nxtidx < num_messages) {
+        /* we could encode mesg->turn with the text of the message,
+           but then that text might need to be truncated, and more
+           significantly, restoring the save file with another
+           interface wouldn't know how find and decode or remove it;
+           likewise, restoring another interface's save file with
+           curses wouldn't find the expected turn info;
+           so, we live without that */
+        mesg = get_msg_line(FALSE, nxtidx);
+    } else
+        mesg = (nhprev_mesg *) 0;
+
+    return mesg ? mesg->str : (char *) 0;
+}
+
+/*
+ * This is called by the core savefile restore routines.
+ * Each time we are called, we stuff the string into our message
+ * history recall buffer. The core will send the oldest message
+ * first (actually it sends them in the order they exist in the
+ * save file, but that is supposed to be the oldest first).
+ * These messages get pushed behind any which have been issued
+ * during this session since they come from a previous session
+ * and logically precede anything (like "Restoring save file...")
+ * that's happened now.
+ *
+ * Called with a null pointer to finish up restoration.
+ *
+ * It's also called by the quest pager code when a block message
+ * has a one-line summary specified.  We put that line directly
+ * into message history for ^P recall without having displayed it.
+ */
+void
+curses_putmsghistory(msg, restoring_msghist)
+const char *msg;
+boolean restoring_msghist;
+{
+    static boolean initd = FALSE;
+    static int stash_count;
+    static nhprev_mesg *stash_head = 0;
+
+    if (restoring_msghist && !initd) {
+        /* hide any messages we've gathered since starting current session
+           so that the ^P data will start out empty as we add ones being
+           restored from save file; we'll put these back after that's done */
+        stash_count = num_messages, num_messages = 0;
+        stash_head = first_mesg, first_mesg = (nhprev_mesg *) 0;
+        last_mesg = (nhprev_mesg *) 0; /* no need to remember the tail */
+        initd = TRUE;
+    }
+
+    if (msg) {
+        mesg_add_line(msg);
+        /* treat all saved and restored messages as turn #1 */
+        last_mesg->turn = 1L;
+    } else if (stash_count) {
+        nhprev_mesg *mesg;
+        long mesg_turn;
+
+        /* put any messages generated during the beginning of the current
+           session back; they logically follow any from the previous
+           session's save file */
+        while (stash_count > 0) {
+            /* we could manipulate the linked list directly but treating
+               stashed messages as newly occurring ones is much simpler;
+               we ignore the backlinks because the list is destroyed as it
+               gets processed hence there can't be any other traversals */
+            mesg = stash_head;
+            stash_head = mesg->next_mesg;
+            --stash_count;
+            mesg_turn = mesg->turn;
+            mesg_add_line(mesg->str);
+            last_mesg->turn = mesg_turn;
+            free((genericptr_t) mesg->str);
+            free((genericptr_t) mesg);
+        }
+        initd = FALSE; /* reset */
+    }
+}
+
 /*cursmesg.c*/

win/curses/cursmesg.h

@@ -18,5 +18,7 @@ void curses_last_messages(void);
 void curses_init_mesg_history(void);
 void curses_prev_mesg(void);
 void curses_count_window(const char *count_text);
+char *curses_getmsghistory(BOOLEAN_P);
+void curses_putmsghistory(const char *, BOOLEAN_P);
 
 #endif /* CURSMESG_H */