Null notifier to support fishd synchronization, so we can select the

synchronization mechanism at runtime

env_universal.cpp

@@ -526,13 +526,3 @@ void env_universal_get_names(wcstring_list_t &lst,
                                    show_unexported);
 }
 
-
-bool synchronizes_via_fishd()
-{
-    if (program_name && ! wcscmp(program_name, L"fishd"))
-    {
-        /* fishd always wants to use fishd */
-        return true;
-    }
-    return false;
-}

env_universal.h

@@ -70,7 +70,4 @@ void env_universal_get_names(wcstring_list_t &list,
 */
 void env_universal_barrier();
 
-/* Temporary */
-bool synchronizes_via_fishd();
-
 #endif

env_universal_common.cpp

@@ -1900,8 +1900,18 @@ class universal_notifier_named_pipe_t : public universal_notifier_t
     }
 };
 
+class universal_notifier_null_t : public universal_notifier_t
+{
+    /* Does nothing! */
+};
+
 static universal_notifier_t::notifier_strategy_t fetch_default_strategy_from_environment()
 {
+    if (! synchronizes_via_fishd())
+    {
+        return universal_notifier_t::strategy_null;
+    }
+    
     universal_notifier_t::notifier_strategy_t result = universal_notifier_t::strategy_default;
 
     const struct
@@ -1983,6 +1993,9 @@ universal_notifier_t *universal_notifier_t::new_notifier_for_strategy(universal_
             
         case strategy_named_pipe:
             return new universal_notifier_named_pipe_t(test_path);
+            
+        case strategy_null:
+            return new universal_notifier_null_t();
         
         default:
             fprintf(stderr, "Unsupported strategy %d\n", strat);
@@ -2022,3 +2035,23 @@ bool universal_notifier_t::notification_fd_became_readable(int fd)
 {
     return false;
 }
+
+static bool initialize_synchronizes_via_fishd()
+{
+    const char *tmp = getenv("fish_use_fishd");
+    return tmp != NULL && from_string<bool>(tmp);
+}
+
+bool synchronizes_via_fishd()
+{
+    if (program_name && ! wcscmp(program_name, L"fishd"))
+    {
+        /* fishd always wants to use fishd */
+        return true;
+    }
+    
+    /* Note that in general we can't change this once it's been set, so we only load it once */
+    static bool result = initialize_synchronizes_via_fishd();
+    return result;
+}
+

env_universal_common.h

@@ -302,7 +302,10 @@ class universal_notifier_t
         strategy_inotify,
         
         // Strategy that uses notify(3). Simple and efficient, but OS X only.
-        strategy_notifyd
+        strategy_notifyd,
+        
+        // Null notifier, does nothing
+        strategy_null
     };
 
     protected:
@@ -343,6 +346,9 @@ class universal_notifier_t
 std::string get_machine_identifier();
 bool get_hostname_identifier(std::string *result);
 
+/* Temporary */
+bool synchronizes_via_fishd();
+
 /* Environment variable for requesting a particular universal notifier. See fetch_default_strategy_from_environment for names. */
 #define UNIVERSAL_NOTIFIER_ENV_NAME "fish_universal_notifier"
 

input_common.cpp

@@ -124,7 +124,7 @@ static wint_t readb()
             fd_max = maxi(fd_max, notifier_fd);
         }
         
-        /* Get the suggested delay (possibly none) */
+        /* Get its suggested delay (possibly none) */
         struct timeval tv = {};
         const unsigned long usecs_delay = notifier.usec_delay_between_polls();
         if (usecs_delay > 0)