Don't lose acquirement if you disconnect at the prompt.

People are quite likely to stop and think, consult ##crawl, etc.  And
thinking is tiresome, folks get distracted...  and then it's a time-out,
they turn the computer without thinking and go to sleep, etc.

This adds a new mechanism: "uncancellables", which allows an action to
restart when the game is loaded back.

1 files changed, 42 insertions, 0 deletions

diff --git a/crawl-ref/source/uncancel.cc b/crawl-ref/source/uncancel.cc
new file mode 100644
index 0000000000..3a0eaff3bb
--- /dev/null
+++ b/crawl-ref/source/uncancel.cc
@@ -0,0 +1,42 @@
+/**
+ * @file
+ * @brief User interactions that need to be restarted if the game is forcibly
+ *        saved (via SIGHUP/window close).
+**/
+
+#include "AppHdr.h"
+#include "acquire.h"
+#include "libutil.h"
+#include "player.h"
+#include "state.h"
+#include "uncancel.h"
+
+void add_uncancel(uncancellable_type kind, int arg)
+{
+    you.uncancel.push_back(pair<uncancellable_type, int>(kind, arg));
+}
+
+void run_uncancels()
+{
+    while (!you.uncancel.empty() && !crawl_state.seen_hups)
+    {
+        // changed to -1 if we pop prematurely
+        int act = you.uncancel.size() - 1;
+
+        // Beware of race conditions: it is not enough to check seen_hups,
+        // the action must actually fail as well!  And if it fails but there
+        // was no HUP, it's due to some other reason.
+
+        int arg = you.uncancel[act].second;
+
+        switch (you.uncancel[act].first)
+        {
+        case UNC_ACQUIREMENT:
+            if (!acquirement(OBJ_RANDOM, arg) && crawl_state.seen_hups)
+                return;
+        }
+
+        if (act != -1)
+            erase_any(you.uncancel, act);
+    }
+}