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authorBjörn Gustavsson <[email protected]>2015-10-12 15:14:14 +0200
committerBjörn Gustavsson <[email protected]>2015-12-16 15:52:25 +0100
commite1dc0aa4100f881f4350162bd523c53d38f08b8f (patch)
tree846ac02c1c4636f4f7b275d91c590d343188e5a7 /erts/preloaded/src
parent27b921fef54b7410efdf756d6ad20ce2877fbc6b (diff)
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Simplify get_flag() and get_flag_list()
The get_flag/3 function which returns a default value if the flag doesn't exist, is implemented in terms of get_flag/2 which throws an exception if the flag doesn't exist. get_flag/3 is frequently used for the flags that don't exist, which means that means that an exception will be generated and catched for no good reason. Reimplement get_flag/3 so that it doesn't have to call get_flag/2 and catch an exception. Eliminate the get_flag/2 function by writing a special purpose function for the only time it's used, that is for retrieving the value for the -root flag. As a side-effect, we will get a nicer error message if there is something wrong with the -root flag. Similarly, simplify get_flag_list/3 and remove get_flag_list/2. We can also eliminate search/3 and use the lists:keyfind/3 BIF instead.
Diffstat (limited to 'erts/preloaded/src')
-rw-r--r--erts/preloaded/src/init.erl53
1 files changed, 19 insertions, 34 deletions
diff --git a/erts/preloaded/src/init.erl b/erts/preloaded/src/init.erl
index b166aba81d..a85b41fddb 100644
--- a/erts/preloaded/src/init.erl
+++ b/erts/preloaded/src/init.erl
@@ -724,7 +724,7 @@ do_boot(Flags,Start) ->
do_boot(Init,Flags,Start) ->
process_flag(trap_exit,true),
{Pgm0,Nodes,Id,Path} = prim_load_flags(Flags),
- Root = b2s(get_flag(root, Flags)),
+ Root = get_root(Flags),
PathFls = path_flags(Flags),
Pgm = b2s(Pgm0),
_Pid = start_prim_loader(Init,b2a(Id),Pgm,bs2as(Nodes),
@@ -748,6 +748,14 @@ do_boot(Init,Flags,Start) ->
start_em(Start).
+get_root(Flags) ->
+ case get_argument(root, Flags) of
+ {ok,[[Root]]} ->
+ Root;
+ _ ->
+ exit(no_or_multiple_root_variables)
+ end.
+
bootfile(Flags,Root) ->
b2s(get_flag(boot, Flags, concat([Root,"/bin/start"]))).
@@ -1180,44 +1188,28 @@ get_args([], As) -> {reverse(As),[]}.
%% atom() if a single arg was given.
%% list(atom()) if several args were given.
%%
-get_flag(F,Flags,Default) ->
- case catch get_flag(F,Flags) of
- {'EXIT',_} ->
- Default;
- Value ->
- Value
- end.
-
-get_flag(F,Flags) ->
- case search(F,Flags) of
- {value,{F,[]}} ->
+get_flag(F, Flags, Default) ->
+ case lists:keyfind(F, 1, Flags) of
+ {F,[]} ->
true;
- {value,{F,[V]}} ->
+ {F,[V]} ->
V;
- {value,{F,V}} ->
+ {F,V} ->
V;
_ ->
- exit(list_to_atom(concat(["no ",F," flag"])))
+ Default
end.
%%
%% Internal get_flag function, with default value.
%% Return: list(atom())
%%
-get_flag_list(F,Flags,Default) ->
- case catch get_flag_list(F,Flags) of
- {'EXIT',_} ->
- Default;
- Value ->
- Value
- end.
-
-get_flag_list(F,Flags) ->
- case search(F,Flags) of
- {value,{F,V}} ->
+get_flag_list(F, Flags, Default) ->
+ case lists:keyfind(F, 1, Flags) of
+ {F,[_|_]=V} ->
V;
_ ->
- exit(list_to_atom(concat(["no ",F," flag"])))
+ Default
end.
%%
@@ -1290,13 +1282,6 @@ reverse([A, B]) ->
reverse([A, B | L]) ->
lists:reverse(L, [B, A]). % BIF
-search(Key, [H|_T]) when is_tuple(H), element(1, H) =:= Key ->
- {value, H};
-search(Key, [_|T]) ->
- search(Key, T);
-search(_Key, []) ->
- false.
-
-spec objfile_extension() -> nonempty_string().
objfile_extension() ->
".beam".