Merge pull request #46 from jaynel/cache-refresh-item

TS-1178 Cache refresh item with no_value_available

Author: jaynel

example/cxy_synch_trace.erl

@@ -1,7 +1,7 @@
 %%%------------------------------------------------------------------------------
-%%% @copyright (c) 2014, DuoMark International, Inc.
+%%% @copyright (c) 2014-2015, DuoMark International, Inc.
 %%% @author Jay Nelson <jay@duomark.com> [http://duomark.com/]
-%%% @reference 2013 Development sponsored by TigerText, Inc. [http://tigertext.com/]
+%%% @reference 2014-2015 Development sponsored by TigerText, Inc. [http://tigertext.com/]
 %%% @reference The license is based on the template for Modified BSD from
 %%%   <a href="http://opensource.org/licenses/BSD-3-Clause">OSI</a>
 %%% @doc

src/cxy_cache.erl

@@ -1,7 +1,7 @@
 %%%------------------------------------------------------------------------------
-%%% @copyright (c) 2013-2014, DuoMark International, Inc.
+%%% @copyright (c) 2013-2015, DuoMark International, Inc.
 %%% @author Jay Nelson <jay@duomark.com>
-%%% @reference 2013-2014 Development sponsored by TigerText, Inc. [http://tigertext.com/]
+%%% @reference 2013-2015 Development sponsored by TigerText, Inc. [http://tigertext.com/]
 %%% @reference The license is based on the template for Modified BSD from
 %%%   <a href="http://opensource.org/licenses/BSD-3-Clause">OSI</a>
 %%% @doc
@@ -67,7 +67,7 @@
 -type cached_key()       :: term().
 -type cached_value()     :: term().
 -type cached_value_vsn() :: term().
--callback create_key_value(cached_key()) -> {cached_value_vsn(), cached_value()}.
+-callback create_key_value(cached_key()) -> {cached_value_vsn(), cached_value()} | no_value_available.
 
 %% Return 'true' if Vsn2 later than Vsn1, otherwise 'false'.
 %% -optional_callback is_later_version(Vsn1::cached_value_vsn(), Vsn2::cached_value_vsn()) -> boolean().
@@ -308,13 +308,12 @@ replace_check_generation_fun(Cache_Name, Fun)
 %%%------------------------------------------------------------------------------
 
 -spec delete_item  (cache_name(), cached_key()) -> true.
--spec fetch_item   (cache_name(), cached_key()) -> cached_value() | {error, tuple()}.
--spec refresh_item (cache_name(), cached_key()) -> cached_value() | {error, tuple()}.
+-spec fetch_item   (cache_name(), cached_key()) -> cached_value() | no_value_available | {error, tuple()}.
+-spec refresh_item (cache_name(), cached_key()) -> cached_value() | no_value_available | {error, tuple()}.
 -spec refresh_item (cache_name(), cached_key(), {cached_value_vsn(), cached_value()})
-                   -> cached_value() | {error, tuple()}.
--spec fetch_item_version (cache_name(), cached_key()) -> cached_value_vsn() | {} | {error, tuple()}.
--spec get_and_clear_counts(cache_name())
-                          -> {cache_name(), proplists:proplist()}.
+                   -> cached_value() | no_value_available | {error, tuple()}.
+-spec fetch_item_version (cache_name(), cached_key()) -> cached_value_vsn() | no_value_available | {error, tuple()}.
+-spec get_and_clear_counts(cache_name()) -> {cache_name(), proplists:proplist()}.
 
 -define(WHEN_GEN_EXISTS(__Gen_Id, __Code), ets:info(__Gen_Id, type) =:= set andalso __Code).
 
@@ -357,7 +356,7 @@ fetch_item(Cache_Name, Key) ->
     Not_Found_Fn = fun(Fn_Cache_Name, Fn_New_Gen_Id, Fn_Old_Gen_Id, Fn_Mod, Fn_Key, _Object) ->
                            copy_old_value_if_found(Fn_Cache_Name, Fn_New_Gen_Id, Fn_Old_Gen_Id, Fn_Mod,Fn_Key)
                    end,
-    access_item(Cache_Name, Key, Found_Fn, Not_Found_Fn, {}).
+    access_item(Cache_Name, Key, Found_Fn, Not_Found_Fn, no_value_available).
 
 %% Fetch from Generation 1 or 2, after updating with a newer key version or leaving existing newest key version.
 refresh_item(Cache_Name, Key) ->
@@ -370,7 +369,7 @@ refresh_item(Cache_Name, Key) ->
                                                               Fn_Mod,Fn_Key,Fn_Obj),
                            return_cache_miss(Fn_Cache_Name, Fn_New_Cached_Value)
                    end,
-    access_item(Cache_Name, Key, Found_Fn, Not_Found_Fn, {}).
+    access_item(Cache_Name, Key, Found_Fn, Not_Found_Fn, no_value_available).
 
 %% Fetch from Generation 1 or 2, after updating with a newer obj version or leaving existing newest obj version.
 refresh_item(Cache_Name, Key, {Possibly_New_Vsn, Possibly_New_Value} = Possibly_New_Object) ->
@@ -393,7 +392,7 @@ fetch_item_version(Cache_Name, Key) ->
     Not_Found_Fn = fun(Fn_Cache_Name, _New_Gen_Id, Fn_Old_Gen_Id, _Mod, Fn_Key, _Obj) ->
                            fetch_gen2_version(Fn_Cache_Name, Fn_Old_Gen_Id, Fn_Key)
                    end,
-    access_item(Cache_Name, Key, Found_Fn, Not_Found_Fn, {}).
+    access_item(Cache_Name, Key, Found_Fn, Not_Found_Fn, no_value_available).
 
 %% Old generation function for getting just the version of a cached value entry.
 fetch_gen2_version(Cache_Name, Old_Gen_Id, Key) ->
@@ -403,12 +402,13 @@ fetch_gen2_version(Cache_Name, Old_Gen_Id, Key) ->
         [#cxy_cache_value{key=Key, version=Version}] ->
             Version;
         [] ->
-            {}
+            no_value_available
     end.
 
 %% Migrate an old value forward to the new generation and then clobber
 %% if the key generates a newer version. Otherwise leave the existing
-%% version in place.
+%% version in place, unless there is now no_value_available, in which
+%% case the entry is deleted from the cache.
 refresh_item(Type, Cache_Name, New_Gen_Id, Old_Gen_Id, Mod, Key, Object) ->
     try ets:lookup(Old_Gen_Id, Key) of
 
@@ -419,7 +419,22 @@ refresh_item(Type, Cache_Name, New_Gen_Id, Old_Gen_Id, Mod, Key, Object) ->
         [#cxy_cache_value{key=Key} = Old_Obj] ->
             insert_to_new_gen(Cache_Name, New_Gen_Id, Mod, Old_Obj),
             %% Then try to clobber it with a newly created value.
-            refresh_now(Type, Cache_Name, New_Gen_Id, Mod, Key, Object)
+            Cached_Value = case {Type, Object} of
+                               {key, _} ->
+                                   create_new_value(Cache_Name, New_Gen_Id, Mod, Key);
+                               {obj, no_value_available} ->
+                                   no_value_available;
+                               {obj, _} ->
+                                   {Possibly_New_Vsn, Possibly_New_Value} = Object,
+                                   insert_value_if_newer(Cache_Name, New_Gen_Id, Mod,
+                                                         Key, Possibly_New_Vsn, Possibly_New_Value)
+                           end,
+            case Cached_Value of
+                no_value_available -> ?WHEN_GEN_EXISTS(New_Gen_Id, ets:delete(New_Gen_Id, Key)),
+                                      ?WHEN_GEN_EXISTS(Old_Gen_Id, ets:delete(Old_Gen_Id, Key)),
+                                      return_cache_miss(Cache_Name, no_value_available);
+                {_Version, _Value} -> return_cache_refresh(Cache_Name, Cached_Value)
+            end
     catch
         %% Old generation was likely eliminated by another request, try creating a new value.
         %% The value will get inserted into 'old_gen' because New_Gen_Id must've been demoted.
@@ -456,7 +471,8 @@ copy_old_value_if_found(Cache_Name, New_Gen_Id, Old_Gen_Id, Mod, Key) ->
 
 cache_miss(Cache_Name, New_Gen_Id, Mod, Key) ->
     case create_new_value(Cache_Name, New_Gen_Id, Mod, Key) of
-        {error, _} = Error -> Error;
+        {error, _} = Error -> return_cache_miss(Cache_Name, Error);
+        no_value_available -> return_cache_miss(Cache_Name, no_value_available);
         Cached_Value       -> return_cache_miss(Cache_Name, Cached_Value)
     end.
 
@@ -501,8 +517,8 @@ get_and_clear_counts(Cache_Name) ->
 %% Create a new value from the cache Mod:create_key_value(Key) but watch for errors in generating it.
 create_new_value(Cache_Name, New_Gen_Id, Mod, Key) ->
     try Mod:create_key_value(Key) of
-        {Version, Value} ->
-            insert_value_if_newer(Cache_Name, New_Gen_Id, Mod, Key, Version, Value)
+        no_value_available -> no_value_available;
+        {Version, Value}   -> insert_value_if_newer(Cache_Name, New_Gen_Id, Mod, Key, Version, Value)
     catch Type:Class ->
             Error = {error, {Type,Class, {creating_new_value_with, Mod, Key}}},
             return_cache_error(Cache_Name, Error)

src/cxy_cache_fsm.erl

@@ -1,7 +1,7 @@
 %%%------------------------------------------------------------------------------
-%%% @copyright (c) 2013-2014, DuoMark International, Inc.
+%%% @copyright (c) 2013-2015, DuoMark International, Inc.
 %%% @author Jay Nelson <jay@duomark.com>
-%%% @reference 2013-2014 Development sponsored by TigerText, Inc. [http://tigertext.com/]
+%%% @reference 2013-2015 Development sponsored by TigerText, Inc. [http://tigertext.com/]
 %%% @reference The license is based on the template for Modified BSD from
 %%%   <a href="http://opensource.org/licenses/BSD-3-Clause">OSI</a>
 %%% @doc

src/cxy_cache_sup.erl

@@ -1,7 +1,7 @@
 %%%------------------------------------------------------------------------------
-%%% @copyright (c) 2013-2014, DuoMark International, Inc.
+%%% @copyright (c) 2013-2015, DuoMark International, Inc.
 %%% @author Jay Nelson <jay@duomark.com>
-%%% @reference 2013-2014 Development sponsored by TigerText, Inc. [http://tigertext.com/]
+%%% @reference 2013-2015 Development sponsored by TigerText, Inc. [http://tigertext.com/]
 %%% @reference The license is based on the template for Modified BSD from
 %%%   <a href="http://opensource.org/licenses/BSD-3-Clause">OSI</a>
 %%% @doc

src/cxy_ctl.erl

@@ -1,7 +1,7 @@
 %%%------------------------------------------------------------------------------
-%%% @copyright (c) 2013-2014, DuoMark International, Inc.
+%%% @copyright (c) 2013-2015, DuoMark International, Inc.
 %%% @author Jay Nelson <jay@duomark.com> [http://duomark.com/]
-%%% @reference 2013-2014 Development sponsored by TigerText, Inc. [http://tigertext.com/]
+%%% @reference 2013-2015 Development sponsored by TigerText, Inc. [http://tigertext.com/]
 %%% @reference The license is based on the template for Modified BSD from
 %%%   <a href="http://opensource.org/licenses/BSD-3-Clause">OSI</a>
 %%% @doc
@@ -238,8 +238,8 @@ adjust_task_limits(Task_Limits) ->
 %%   many, execute the task inline. Returns neither a pid nor a result.
 %% @end
 
--spec execute_task(atom(), atom(), atom(), list())               -> ok.
--spec execute_task(atom(), atom(), atom(), list(), dict_props()) -> ok.
+-spec execute_task(atom(), atom(), atom(), list())                          -> ok.
+-spec execute_task(atom(), atom(), atom(), list(), all_keys | dict_props()) -> ok.
 
 execute_task(Task_Type, Mod, Fun, Args) ->
     internal_execute_task(Task_Type, Mod, Fun, Args, inline, none).
@@ -254,8 +254,9 @@ execute_task(Task_Type, Mod, Fun, Args, Dict_Props) ->
 %%   many, return {max_pids, Max} without executing, rather than ok.
 %% @end
 
--spec maybe_execute_task(atom(), atom(), atom(), list())             -> ok | {max_pids, non_neg_integer()}.
--spec maybe_execute_task(atom(), atom(), atom(), list(), dict_props()) -> ok | {max_pids, non_neg_integer()}.
+-spec maybe_execute_task(atom(), atom(), atom(), list()) -> ok | {max_pids, non_neg_integer()}.
+-spec maybe_execute_task(atom(), atom(), atom(), list(),
+                         all_keys | dict_props()) -> ok | {max_pids, non_neg_integer()}.
 
 maybe_execute_task(Task_Type, Mod, Fun, Args) ->
     internal_execute_task(Task_Type, Mod, Fun, Args, refuse, none).
@@ -294,8 +295,8 @@ internal_execute_task(Task_Type, Mod, Fun, Args, Over_Limit_Action, Dict_Props)
 %%   if inlined.
 %% @end
 
--spec execute_pid_link(atom(), atom(), atom(), list())               -> pid() | {inline, any()}.
--spec execute_pid_link(atom(), atom(), atom(), list(), dict_props()) -> pid() | {inline, any()}.
+-spec execute_pid_link(atom(), atom(), atom(), list())                          -> pid() | {inline, any()}.
+-spec execute_pid_link(atom(), atom(), atom(), list(), all_keys | dict_props()) -> pid() | {inline, any()}.
 
 execute_pid_link(Task_Type, Mod, Fun, Args) ->
     internal_execute_pid(Task_Type, Mod, Fun, Args, link, inline, none).
@@ -309,8 +310,9 @@ execute_pid_link(Task_Type, Mod, Fun, Args, Dict_Props) ->
 %%   many, return {max_pids, Max_Count} instead of linked pid.
 %% @end
 
--spec maybe_execute_pid_link(atom(), atom(), atom(), list())               -> pid() | {max_pids, non_neg_integer()}.
--spec maybe_execute_pid_link(atom(), atom(), atom(), list(), dict_props()) -> pid() | {max_pids, non_neg_integer()}.
+-spec maybe_execute_pid_link(atom(), atom(), atom(), list()) -> pid() | {max_pids, non_neg_integer()}.
+-spec maybe_execute_pid_link(atom(), atom(), atom(), list(),
+                             all_keys | dict_props()) -> pid() | {max_pids, non_neg_integer()}.
 
 maybe_execute_pid_link(Task_Type, Mod, Fun, Args) ->
     internal_execute_pid(Task_Type, Mod, Fun, Args, link, refuse, none).
@@ -325,8 +327,9 @@ maybe_execute_pid_link(Task_Type, Mod, Fun, Args, Dict_Props) ->
 %%   so the process can be monitored, or results if inlined.
 %% @end
 
--spec execute_pid_monitor(atom(), atom(), atom(), list())               -> {pid(), reference()} | {inline, any()}.
--spec execute_pid_monitor(atom(), atom(), atom(), list(), dict_props()) -> {pid(), reference()} | {inline, any()}.
+-spec execute_pid_monitor(atom(), atom(), atom(), list()) -> {pid(), reference()} | {inline, any()}.
+-spec execute_pid_monitor(atom(), atom(), atom(), list(),
+                          all_keys | dict_props()) -> {pid(), reference()} | {inline, any()}.
 
 execute_pid_monitor(Task_Type, Mod, Fun, Args) ->
     internal_execute_pid(Task_Type, Mod, Fun, Args, monitor, inline, none).
@@ -340,8 +343,9 @@ execute_pid_monitor(Task_Type, Mod, Fun, Args, Dict_Props) ->
 %%   many, return {max_pids, Max_Count} instead of {pid(), reference()}.
 %% @end
 
--spec maybe_execute_pid_monitor(atom(), atom(), atom(), list())               -> {pid(), reference()} | {max_pids, non_neg_integer()}.
--spec maybe_execute_pid_monitor(atom(), atom(), atom(), list(), dict_props()) -> {pid(), reference()} | {max_pids, non_neg_integer()}.
+-spec maybe_execute_pid_monitor(atom(), atom(), atom(), list()) -> {pid(), reference()} | {max_pids, non_neg_integer()}.
+-spec maybe_execute_pid_monitor(atom(), atom(), atom(), list(),
+                                all_keys | dict_props()) -> {pid(), reference()} | {max_pids, non_neg_integer()}.
 
 maybe_execute_pid_monitor(Task_Type, Mod, Fun, Args) ->
     internal_execute_pid(Task_Type, Mod, Fun, Args, monitor, refuse, none).

src/cxy_synch.erl

@@ -1,7 +1,7 @@
 %%%------------------------------------------------------------------------------
-%%% @copyright (c) 2014, DuoMark International, Inc.
+%%% @copyright (c) 2014-2015, DuoMark International, Inc.
 %%% @author Jay Nelson <jay@duomark.com> [http://duomark.com/]
-%%% @reference 2013 Development sponsored by TigerText, Inc. [http://tigertext.com/]
+%%% @reference 2014-2015 Development sponsored by TigerText, Inc. [http://tigertext.com/]
 %%% @reference The license is based on the template for Modified BSD from
 %%%   <a href="http://opensource.org/licenses/BSD-3-Clause">OSI</a>
 %%% @doc

src/epocxy.app.src

@@ -2,10 +2,11 @@
 %% -*- tab-width: 4;erlang-indent-level: 4;indent-tabs-mode: nil -*-
 %% ex: ts=4 sw=4 et
 
+
 {application, epocxy,
  [
   {id, "epocxy"},
-  {vsn, "0.9.8c"},
+  {vsn, "0.9.8d"},
   {description, "Erlang Patterns of Concurrency"},
   {modules,      [
                   ets_buffer,

src/ets_buffer.erl

@@ -1,7 +1,7 @@
 %%%------------------------------------------------------------------------------
-%%% @copyright (c) 2013-2014, DuoMark International, Inc.
+%%% @copyright (c) 2013-2015, DuoMark International, Inc.
 %%% @author Jay Nelson <jay@duomark.com> [http://duomark.com/]
-%%% @reference 2013-2014 Development sponsored by TigerText, Inc. [http://tigertext.com/]
+%%% @reference 2013-2015 Development sponsored by TigerText, Inc. [http://tigertext.com/]
 %%% @reference The license is based on the template for Modified BSD from
 %%%   <a href="http://opensource.org/licenses/BSD-3-Clause">OSI</a>
 %%% @doc

test/epocxy/cxy_cache_SUITE.erl

@@ -1,7 +1,7 @@
 %%%------------------------------------------------------------------------------
-%%% @copyright (c) 2013-2014, DuoMark International, Inc.
+%%% @copyright (c) 2013-2015, DuoMark International, Inc.
 %%% @author Jay Nelson <jay@duomark.com>
-%%% @reference 2013-2014 Development sponsored by TigerText, Inc. [http://tigertext.com/]
+%%% @reference 2013-2015 Development sponsored by TigerText, Inc. [http://tigertext.com/]
 %%% @reference The license is based on the template for Modified BSD from
 %%%   <a href="http://opensource.org/licenses/BSD-3-Clause">OSI</a>
 %%% @doc
@@ -380,11 +380,11 @@ validate_force_refresh(Type, Cache_Name, Obj_Record_Type, Obj_Instance_Key, Old_
 
     %% Now test the old generation with refresh...
     ct:comment("Create a new generation for cache: ~p", [Cache_Name]),
-    {} = ?TM:fetch_item_version(Cache_Name, missing_object),
+    no_value_available = ?TM:fetch_item_version(Cache_Name, missing_object),
     Expected_Frog = ?TM:fetch_item(Cache_Name, Obj_Instance_Key),
     true = ?TM:maybe_make_new_generation(Cache_Name),
     true = check_version(Type, Cache_Name, Obj_Instance_Key, New_Time),
-    {} = ?TM:fetch_item_version(Cache_Name, missing_object),
+    no_value_available = ?TM:fetch_item_version(Cache_Name, missing_object),
 
     %% Refresh the old generation item...
     Expected_Frog = refresh(Type, Cache_Name, Obj_Instance_Key, {Old_Time, Expected_Frog}),

test/epocxy/cxy_ctl_SUITE.erl

@@ -1,3 +1,15 @@
+%%%------------------------------------------------------------------------------
+%%% @copyright (c) 2013-2015, DuoMark International, Inc.
+%%% @author Jay Nelson <jay@duomark.com>
+%%% @reference 2013-2015 Development sponsored by TigerText, Inc. [http://tigertext.com/]
+%%% @reference The license is based on the template for Modified BSD from
+%%%   <a href="http://opensource.org/licenses/BSD-3-Clause">OSI</a>
+%%% @doc
+%%%   Tests for cxy_ctl using common test.
+%%%
+%%% @since 0.9.6
+%%% @end
+%%%------------------------------------------------------------------------------
 -module(cxy_ctl_SUITE).
 -auth('jay@duomark.com').
 -vsn('').
@@ -123,7 +135,7 @@ check_execute_task(_Config) ->
     true = ?TM:init(Limits),
     Ets_Table = ets:new(check_execute_task, [public, named_table]),
 
-    try
+    _ = try
         %% Inline update the shared ets table...
         ok = ?TM:execute_task(Inline_Type, ets, insert_new, [Ets_Table, {joe, 5}]),
         [{joe, 5}] = ets:lookup(Ets_Table, joe),
@@ -191,7 +203,7 @@ check_execute_pid_link(_Config) ->
 
     %% When inline, update our process dictionary...
     Old_Joe = erase(joe),
-    try
+    _ = try
         {inline, undefined} = ?TM:execute_pid_link(Inline_Type, erlang, put, [joe, 5]),
         5 = get(joe),
         {inline, 5} = ?TM:execute_pid_link(Inline_Type, erlang, put, [joe, 7]),
@@ -202,7 +214,7 @@ check_execute_pid_link(_Config) ->
     %% When spawned, it affects a new process dictionary, not ours.
     Self = self(),
     Old_Joe = erase(joe),
-    try
+    _ = try
         undefined = get(joe),
         New_Pid = ?TM:execute_pid_link(Spawn_Type, ?MODULE, put_pdict, [joe, 5]),
         false = (New_Pid =:= Self),
@@ -386,7 +398,7 @@ get_pdict() ->
 
 filter_pdict() -> [{K, V} || {{cxy_ctl, K}, V} <- get()].
 
--spec fetch_ages() -> pdict_timeout | {get_dict, pid(), proplists:proplist()}.
+-spec fetch_ages() -> pdict_timeout | {get_pdict, pid(), proplists:proplist()}.
 fetch_ages() -> get_pdict().
 
 -spec fetch_ets_ages(atom() | ets:tid()) -> ok.