[cover] Add support for test_server

OTP-10523

* Added cover:flush(Nodes), which will fetch data from remote nodes
  without stopping cover on those nodes.

* Added cover:get_main_node(), which returns the node name of the main
  node. This is used by test_server to avoid {error,not_main_node}
  when a slave starts another slave (e.g. in test_server's own tests).

3 files changed, 59 insertions, 4 deletions

diff --git a/lib/tools/doc/src/cover.xml b/lib/tools/doc/src/cover.xml
index 683acc025d..be0fd5bd47 100644
--- a/lib/tools/doc/src/cover.xml
+++ b/lib/tools/doc/src/cover.xml
@@ -5,7 +5,7 @@
   <header>
     <copyright>
       <year>2001</year>
-      <year>2011</year>
+      <year>2012</year>
       <holder>Ericsson AB, All Rights Reserved</holder>
     </copyright>
     <legalnotice>
@@ -104,6 +104,8 @@
       remove nodes. The same Cover compiled code will be loaded on each
       node, and analysis will collect and sum up coverage data results
       from all nodes.</p>
+    <p>To only collect data from remote nodes without stopping
+      <c>cover</c> on those nodes, use <c>cover:flush/1</c></p>
   </description>
   <funcs>
     <func>
@@ -477,6 +479,17 @@
           remote nodes is fetched and stored on the main node.</p>
       </desc>
     </func>
+    <func>
+      <name>flush(Nodes) -> ok | {error,not_main_node}</name>
+      <fsummary>Collect cover data from remote nodes.</fsummary>
+      <type>
+        <v>Nodes = [atom()]</v>
+      </type>
+      <desc>
+        <p>Fetch data from the Cover database on the remote nodes and
+        stored on the main node.</p>
+      </desc>
+    </func>
   </funcs>
 
   <section>
diff --git a/lib/tools/src/cover.erl b/lib/tools/src/cover.erl
index e21bd1b88c..fb65206938 100644
--- a/lib/tools/src/cover.erl
+++ b/lib/tools/src/cover.erl
@@ -1,7 +1,7 @@
 %%
 %% %CopyrightBegin%
 %%
-%% Copyright Ericsson AB 2001-2011. All Rights Reserved.
+%% Copyright Ericsson AB 2001-2012. All Rights Reserved.
 %%
 %% The contents of this file are subject to the Erlang Public License,
 %% Version 1.1, (the "License"); you may not use this file except in
@@ -81,8 +81,9 @@
 	 export/1, export/2, import/1,
 	 modules/0, imported/0, imported_modules/0, which_nodes/0, is_compiled/1,
 	 reset/1, reset/0,
+	 flush/1,
 	 stop/0, stop/1]).
--export([remote_start/1]).
+-export([remote_start/1,get_main_node/0]).
 %-export([bump/5]).
 -export([transform/4]). % for test purposes
 
@@ -497,6 +498,19 @@ stop(Node) when is_atom(Node) ->
 stop(Nodes) ->
     call({stop,remove_myself(Nodes,[])}).
 
+%% flush(Nodes) -> ok | {error,not_main_node}
+%%   Nodes = [Node] | Node
+%%   Node = atom()
+%%   Error = {not_cover_compiled,Module}
+flush(Node) when is_atom(Node) ->
+    flush([Node]);
+flush(Nodes) ->
+    call({flush,remove_myself(Nodes,[])}).
+
+%% Used by test_server only. Not documented.
+get_main_node() ->
+    call(get_main_node).
+
 %% bump(Module, Function, Arity, Clause, Line)
 %%   Module = Function = atom()
 %%   Arity = Clause = Line = integer()
@@ -710,6 +724,11 @@ main_process_loop(State) ->
 	    State1 = State#main_state{nodes=State#main_state.nodes--Nodes},
 	    main_process_loop(State1);
 
+	{From, {flush,Nodes}} ->
+	    remote_collect('_',Nodes,false),
+	    reply(From, ok),
+	    main_process_loop(State);
+
 	{From, stop} ->
 	    lists:foreach(
 	      fun(Node) -> 
@@ -796,6 +815,10 @@ main_process_loop(State) ->
 	    State1 = State#main_state{nodes=State#main_state.nodes--[node(Pid)]},
 	    main_process_loop(State1);
 	
+	{From, get_main_node} ->
+	    reply(From, node()),
+	    main_process_loop(State);
+
 	get_status ->
 	    io:format("~p~n",[State]),
 	    main_process_loop(State)
@@ -852,6 +875,10 @@ remote_process_loop(State) ->
             unregister(?SERVER),
 	    remote_reply(State#remote_state.main_node, ok);
 
+	{From, get_main_node} ->
+	    reply(From, State#remote_state.main_node),
+	    remote_process_loop(State);
+
 	get_status ->
 	    io:format("~p~n",[State]),
 	    remote_process_loop(State);
diff --git a/lib/tools/test/cover_SUITE.erl b/lib/tools/test/cover_SUITE.erl
index c2c708d806..950c4ddbcb 100644
--- a/lib/tools/test/cover_SUITE.erl
+++ b/lib/tools/test/cover_SUITE.erl
@@ -326,14 +326,16 @@ distribution(Config) when is_list(Config) ->
     ?line {ok,N1} = ?t:start_node(cover_SUITE_distribution1,slave,[]),
     ?line {ok,N2} = ?t:start_node(cover_SUITE_distribution2,slave,[]),
     ?line {ok,N3} = ?t:start_node(cover_SUITE_distribution3,slave,[]),
+    ?line {ok,N4} = ?t:start_node(cover_SUITE_distribution4,slave,[]),
 
     %% Check that an already compiled module is loaded on new nodes
     ?line {ok,f} = cover:compile(f),
-    ?line {ok,[_,_,_]} = cover:start(nodes()),
+    ?line {ok,[_,_,_,_]} = cover:start(nodes()),
     ?line cover_compiled = code:which(f),
     ?line cover_compiled = rpc:call(N1,code,which,[f]),
     ?line cover_compiled = rpc:call(N2,code,which,[f]),
     ?line cover_compiled = rpc:call(N3,code,which,[f]),
+    ?line cover_compiled = rpc:call(N4,code,which,[f]),
 
     %% Check that a node cannot be started twice
     ?line {ok,[]} = cover:start(N2),
@@ -351,6 +353,7 @@ distribution(Config) when is_list(Config) ->
     ?line cover_compiled = rpc:call(N1,code,which,[v]),
     ?line cover_compiled = rpc:call(N2,code,which,[v]),
     ?line cover_compiled = rpc:call(N3,code,which,[v]),
+    ?line cover_compiled = rpc:call(N4,code,which,[v]),
     
     %% this is lost when the node is killed
     ?line rpc:call(N3,f,f2,[]),
@@ -385,6 +388,18 @@ distribution(Config) when is_list(Config) ->
     %% reset on the remote node(s))
     ?line check_f_calls(1,1),
 
+    %% Another checn that data is not fetched twice, i.e. when flushed
+    %% then analyse should not add the same data again.
+    ?line rpc:call(N4,f,f2,[]),
+    ?line ok = cover:flush(N4),
+    ?line check_f_calls(1,2),
+
+    %% Check that flush collects data so calls are not lost if node is killed
+    ?line rpc:call(N4,f,f2,[]),
+    ?line ok = cover:flush(N4),
+    ?line rpc:call(N4,erlang,halt,[]),
+    ?line check_f_calls(1,3),
+
     %% Check that stop() unloads on all nodes
     ?line ok = cover:stop(),
     ?line timer:sleep(100), %% Give nodes time to unload on slow machines.