Address Eric's comments

 - introduce init_recovery_dir/1 to make sure that new recovery dir exists
 - add new sample recoveried index directory and file
 - pass DbName to reset_indexes/3 as mandatory
 - change directory name from .view_recovery to .recovery
 - avoid case double-fold and unreached call

Bugzid: 86318

Author: jiangphcn

src/couch/src/couch_file.erl

@@ -43,7 +43,8 @@
 -export([append_raw_chunk/2, assemble_file_chunk/1, assemble_file_chunk/2]).
 -export([append_term/2, append_term/3, append_term_md5/2, append_term_md5/3]).
 -export([write_header/2, read_header/1]).
--export([delete/2, delete/3, nuke_dir/2, nuke_dir/3, init_delete_dir/1]).
+-export([delete/2, delete/3, nuke_dir/2, nuke_dir/3]).
+-export([init_delete_dir/1, init_recovery_dir/1]).
 
 % gen_server callbacks
 -export([init/1, terminate/2, code_change/3]).
@@ -266,7 +267,7 @@ rename_file(Original) ->
 
 rename_dir(RootDelDir, Original, DbName) ->
     DbDir = binary_to_list(DbName) ++ "_design",
-    Deleted_Index_Dir = filename:join([RootDelDir, ".view_recovery", DbDir]),
+    Deleted_Index_Dir = filename:join([RootDelDir, ".recovery", DbDir]),
     Now = calendar:local_time(),
     filelib:ensure_dir(Deleted_Index_Dir),
     case file:rename(Original, Deleted_Index_Dir) of
@@ -335,6 +336,9 @@ init_delete_dir(RootDir) ->
     end),
     ok.
 
+init_recovery_dir(RootDir) ->
+    Dir = filename:join(RootDir,".recovery"),
+    filelib:ensure_dir(filename:join(Dir,"foo")).
 
 read_header(Fd) ->
     case ioq:call(Fd, find_header, erlang:get(io_priority)) of
@@ -768,7 +772,10 @@ make_filename_fixtures(DbNames) ->
         "shards/00000000-1fffffff/~s.1458336317.couch",
         ".shards/00000000-1fffffff/~s.1458336317_design",
         ".shards/00000000-1fffffff/~s.1458336317_design"
-            "/mrview/3133e28517e89a3e11435dd5ac4ad85a.view"
+            "/mrview/3133e28517e89a3e11435dd5ac4ad85a.view",
+        ".recovery/shards/00000000-1fffffff/~s.1499329402_design",
+        ".recovery/shards/00000000-1fffffff/~s.1499329402_design"
+            "/mrview/8fabddcb28f501d6764afd7def3bd352.view"
     ],
     lists:flatmap(fun(DbName) ->
         lists:map(fun(Format) ->

src/couch/test/couch_file_tests.erl

@@ -438,11 +438,8 @@ nuke_dir_test_() ->
                     [DelDir] -> remove_dir(DelDir);
                     _ -> ok
                 end,
-                RecDirPaths = RootDir ++ "/.view_recovery" ++ "/*_design",
-                case filelib:wildcard(RecDirPaths) of
-                    RecDirs -> [remove_dir(Dir) || Dir <- RecDirs];
-                    [] -> ok
-                end
+                RecDirPaths = RootDir ++ "/.recovery" ++ "/*_design",
+                [remove_dir(Dir) || Dir <- filelib:wildcard(RecDirPaths)]
             end,
             [
                 fun(Cfg) ->
@@ -488,7 +485,7 @@ make_rename_dir_test_case({RootDir, ViewDir, DBName}, EnableRecovery, Context) -
     ),
     DirExistsAfter = filelib:is_dir(ViewDir),
     RenamedDirs = if Context =:= delete ->
-        filelib:wildcard(RootDir ++ "/.view_recovery" ++ "/*_design");
+        filelib:wildcard(RootDir ++ "/.recovery" ++ "/*_design");
     true ->
         Ext = filename:extension(ViewDir),
         filelib:wildcard(RootDir ++ "/*.deleted" ++ Ext)

src/couch_index/src/couch_index_server.erl

@@ -122,6 +122,7 @@ init([]) ->
     couch_event:link_listener(?MODULE, handle_db_event, nil, [all_dbs]),
     RootDir = couch_index_util:root_dir(),
     couch_file:init_delete_dir(RootDir),
+    couch_file:init_recovery_dir(RootDir),
     {ok, #st{root_dir=RootDir}}.
 
 
@@ -154,13 +155,13 @@ handle_call({async_error, {DbName, _DDocId, Sig}, Error}, _From, State) ->
     [gen_server:reply(From, Error) || From <- Waiters],
     ets:delete(?BY_SIG, {DbName, Sig}),
     {reply, ok, State};
-handle_call({reset_indexes, Options}, _From, State) ->
-    reset_indexes(Options, State#st.root_dir),
+handle_call({reset_indexes, DbName, Options}, _From, State) ->
+    reset_indexes(DbName, State#st.root_dir, Options),
     {reply, ok, State}.
 
 
-handle_cast({reset_indexes, Options}, State) ->
-    reset_indexes(Options, State#st.root_dir),
+handle_cast({reset_indexes, DbName, Options}, State) ->
+    reset_indexes(DbName, State#st.root_dir, Options),
     {noreply, State}.
 
 handle_info({'EXIT', Pid, Reason}, Server) ->
@@ -219,8 +220,7 @@ new_index({Mod, IdxState, DbName, Sig}) ->
     end.
 
 
-reset_indexes(Options, Root) ->
-    DbName = couch_util:get_value(db_name, Options),
+reset_indexes(DbName, Root, Options) ->
     % shutdown all the updaters and clear the files, the db got changed
     Fun = fun({_, {DDocId, Sig}}) ->
         [{_, Pid}] = ets:lookup(?BY_SIG, {DbName, Sig}),
@@ -231,7 +231,8 @@ reset_indexes(Options, Root) ->
     end,
     lists:foreach(Fun, ets:lookup(?BY_DB, DbName)),
     Path = couch_index_util:index_dir("", DbName),
-    couch_file:nuke_dir(Root, Path, Options).
+    Options1 = [{db_name, DbName} | Options],
+    couch_file:nuke_dir(Root, Path, Options1).
 
 
 add_to_ets(DbName, Sig, DDocId, Pid) ->
@@ -247,10 +248,10 @@ rem_from_ets(DbName, Sig, DDocId, Pid) ->
 
 
 handle_db_event(DbName, created, St) ->
-    gen_server:cast(?MODULE, {reset_indexes, [{db_name, DbName}, {context, []}]}),
+    gen_server:cast(?MODULE, {reset_indexes, DbName, []}),
     {ok, St};
 handle_db_event(DbName, deleted, St) ->
-    gen_server:cast(?MODULE, {reset_indexes, [{db_name, DbName}, {context, delete}]}),
+    gen_server:cast(?MODULE, {reset_indexes, DbName, [{context, delete}]}),
     {ok, St};
 handle_db_event(DbName, {ddoc_updated, DDocId}, St) ->
     lists:foreach(fun({_DbName, {_DDocId, Sig}}) ->