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-rw-r--r--lib/kernel/src/file.erl16
-rw-r--r--lib/kernel/src/file_io_server.erl8
-rw-r--r--lib/kernel/src/ram_file.erl33
3 files changed, 55 insertions, 2 deletions
diff --git a/lib/kernel/src/file.erl b/lib/kernel/src/file.erl
index 5da359fdf1..a694ed0708 100644
--- a/lib/kernel/src/file.erl
+++ b/lib/kernel/src/file.erl
@@ -36,7 +36,7 @@
%% Specialized
-export([ipread_s32bu_p32bu/3]).
%% Generic file contents.
--export([open/2, close/1,
+-export([open/2, close/1, advise/4,
read/2, write/2,
pread/2, pread/3, pwrite/2, pwrite/3,
read_line/1,
@@ -89,6 +89,8 @@
-type date() :: {pos_integer(), pos_integer(), pos_integer()}.
-type time() :: {non_neg_integer(), non_neg_integer(), non_neg_integer()}.
-type date_time() :: {date(), time()}.
+-type posix_file_advise() :: 'normal' | 'sequential' | 'random' | 'no_reuse' |
+ 'will_need' | 'dont_need'.
%%%-----------------------------------------------------------------
%%% General functions
@@ -352,6 +354,18 @@ close(#file_descriptor{module = Module} = Handle) ->
close(_) ->
{error, badarg}.
+-spec advise(File :: io_device(), Offset :: integer(),
+ Length :: integer(), Advise :: posix_file_advise()) ->
+ 'ok' | {'error', posix()}.
+
+advise(File, Offset, Length, Advise) when is_pid(File) ->
+ R = file_request(File, {advise, Offset, Length, Advise}),
+ wait_file_reply(File, R);
+advise(#file_descriptor{module = Module} = Handle, Offset, Length, Advise) ->
+ Module:advise(Handle, Offset, Length, Advise);
+advise(_, _, _, _) ->
+ {error, badarg}.
+
-spec read(File :: io_device(), Size :: non_neg_integer()) ->
'eof' | {'ok', [char()] | binary()} | {'error', posix()}.
diff --git a/lib/kernel/src/file_io_server.erl b/lib/kernel/src/file_io_server.erl
index d0b30192b3..39dc32bb79 100644
--- a/lib/kernel/src/file_io_server.erl
+++ b/lib/kernel/src/file_io_server.erl
@@ -198,6 +198,14 @@ io_reply(From, ReplyAs, Reply) ->
%%%-----------------------------------------------------------------
%%% file requests
+file_request({advise,Offset,Length,Advise},
+ #state{handle=Handle}=State) ->
+ case ?PRIM_FILE:advise(Handle, Offset, Length, Advise) of
+ {error,_}=Reply ->
+ {stop,normal,Reply,State};
+ Reply ->
+ {reply,Reply,State}
+ end;
file_request({pread,At,Sz},
#state{handle=Handle,buf=Buf,read_mode=ReadMode}=State) ->
case position(Handle, At, Buf) of
diff --git a/lib/kernel/src/ram_file.erl b/lib/kernel/src/ram_file.erl
index 0230cb4e0a..2bfb2cd021 100644
--- a/lib/kernel/src/ram_file.erl
+++ b/lib/kernel/src/ram_file.erl
@@ -28,7 +28,7 @@
%% Specialized file operations
-export([get_size/1, get_file/1, set_file/2, get_file_close/1]).
--export([compress/1, uncompress/1, uuencode/1, uudecode/1]).
+-export([compress/1, uncompress/1, uuencode/1, uudecode/1, advise/4]).
-export([open_mode/1]). %% used by ftp-file
@@ -71,6 +71,7 @@
-define(RAM_FILE_UUENCODE, 35).
-define(RAM_FILE_UUDECODE, 36).
-define(RAM_FILE_SIZE, 37).
+-define(RAM_FILE_ADVISE, 38).
%% Open modes for RAM_FILE_OPEN
-define(RAM_FILE_MODE_READ, 1).
@@ -91,6 +92,14 @@
-define(RAM_FILE_RESP_NUMBER, 3).
-define(RAM_FILE_RESP_INFO, 4).
+%% POSIX file advises
+-define(POSIX_FADV_NORMAL, 0).
+-define(POSIX_FADV_RANDOM, 1).
+-define(POSIX_FADV_SEQUENTIAL, 2).
+-define(POSIX_FADV_WILLNEED, 3).
+-define(POSIX_FADV_DONTNEED, 4).
+-define(POSIX_FADV_NOREUSE, 5).
+
%% --------------------------------------------------------------------------
%% Generic file contents operations.
%%
@@ -352,6 +361,28 @@ uudecode(#file_descriptor{module = ?MODULE, data = Port}) ->
uudecode(#file_descriptor{}) ->
{error, enotsup}.
+advise(#file_descriptor{module = ?MODULE, data = Port}, Offset,
+ Length, Advise) ->
+ Cmd0 = <<?RAM_FILE_ADVISE, Offset:64/signed, Length:64/signed>>,
+ case Advise of
+ normal ->
+ call_port(Port, <<Cmd0/binary, ?POSIX_FADV_NORMAL:32/signed>>);
+ random ->
+ call_port(Port, <<Cmd0/binary, ?POSIX_FADV_RANDOM:32/signed>>);
+ sequential ->
+ call_port(Port, <<Cmd0/binary, ?POSIX_FADV_SEQUENTIAL:32/signed>>);
+ will_need ->
+ call_port(Port, <<Cmd0/binary, ?POSIX_FADV_WILLNEED:32/signed>>);
+ dont_need ->
+ call_port(Port, <<Cmd0/binary, ?POSIX_FADV_DONTNEED:32/signed>>);
+ no_reuse ->
+ call_port(Port, <<Cmd0/binary, ?POSIX_FADV_NOREUSE:32/signed>>);
+ _ ->
+ {error, einval}
+ end;
+advise(#file_descriptor{}, _Offset, _Length, _Advise) ->
+ {error, enotsup}.
+
%%%-----------------------------------------------------------------