Merge branch 'fm/file-operations' into dev

* fm/file-operations:
  Update preloaded modules
  Add file:advise/4 - a wrapper to the POSIX syscall posix_fadvise
  Add file:datasync/1 for syncing file contents only
  sys.h: Correct the get_int64() macro

OTP-8637 fm/file-operations

The functions file:advise/4 and file:datasync/1 have been added. (Thanks to
Filipe David Manana.)

3 files changed, 83 insertions, 9 deletions

diff --git a/lib/kernel/src/file.erl b/lib/kernel/src/file.erl
index 46ffa9d708..a694ed0708 100644
--- a/lib/kernel/src/file.erl
+++ b/lib/kernel/src/file.erl
@@ -36,11 +36,11 @@
 %% 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,
-	 position/2, truncate/1, sync/1,
+	 position/2, truncate/1, datasync/1, sync/1,
 	 copy/2, copy/3]).
 %% High level operations
 -export([consult/1, path_consult/2]).
@@ -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()}.
 
@@ -472,6 +486,16 @@ pwrite(#file_descriptor{module = Module} = Handle, Offs, Bytes) ->
 pwrite(_, _, _) ->
     {error, badarg}.
 
+-spec datasync(File :: io_device()) -> 'ok' | {'error', posix()}.
+
+datasync(File) when is_pid(File) ->
+    R = file_request(File, datasync),
+    wait_file_reply(File, R);
+datasync(#file_descriptor{module = Module} = Handle) ->
+    Module:datasync(Handle);
+datasync(_) ->
+    {error, badarg}.
+
 -spec sync(File :: io_device()) -> 'ok' | {'error', posix()}.
 
 sync(File) when is_pid(File) ->
diff --git a/lib/kernel/src/file_io_server.erl b/lib/kernel/src/file_io_server.erl
index 3ac35a209d..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
@@ -219,6 +227,14 @@ file_request({pwrite,At,Data},
 	Reply ->
 	    std_reply(Reply, State)
     end;
+file_request(datasync,
+	     #state{handle=Handle}=State) ->
+    case ?PRIM_FILE:datasync(Handle) of
+	{error,_}=Reply ->
+	    {stop,normal,Reply,State};
+	Reply ->
+	    {reply,Reply,State}
+    end;
 file_request(sync, 
 	     #state{handle=Handle}=State) ->
     case ?PRIM_FILE:sync(Handle) of
diff --git a/lib/kernel/src/ram_file.erl b/lib/kernel/src/ram_file.erl
index d996650948..48ea871433 100644
--- a/lib/kernel/src/ram_file.erl
+++ b/lib/kernel/src/ram_file.erl
@@ -1,19 +1,19 @@
 %%
 %% %CopyrightBegin%
-%% 
-%% Copyright Ericsson AB 1997-2009. All Rights Reserved.
-%% 
+%%
+%% Copyright Ericsson AB 1997-2010. 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
 %% compliance with the License. You should have received a copy of the
 %% Erlang Public License along with this software. If not, it can be
 %% retrieved online at http://www.erlang.org/.
-%% 
+%%
 %% Software distributed under the License is distributed on an "AS IS"
 %% basis, WITHOUT WARRANTY OF ANY KIND, either express or implied. See
 %% the License for the specific language governing rights and limitations
 %% under the License.
-%% 
+%%
 %% %CopyrightEnd%
 %%
 -module(ram_file).
@@ -24,11 +24,11 @@
 -export([open/2, close/1]).
 -export([write/2, read/2, copy/3,
 	 pread/2, pread/3, pwrite/2, pwrite/3, 
-	 position/2, truncate/1, sync/1]).
+	 position/2, truncate/1, datasync/1, sync/1]).
 
 %% 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
 
@@ -60,6 +60,7 @@
 -define(RAM_FILE_TRUNCATE,       14).
 -define(RAM_FILE_PREAD,          17).
 -define(RAM_FILE_PWRITE,         18).
+-define(RAM_FILE_FDATASYNC,      19).
 
 %% Other operations
 -define(RAM_FILE_GET,            30).
@@ -70,6 +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).
@@ -90,6 +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.
 %%
@@ -167,6 +177,8 @@ copy(#file_descriptor{module = ?MODULE} = Source,
     %% XXX Should be moved down to the driver for optimization.
     file:copy_opened(Source, Dest, Length).
 
+datasync(#file_descriptor{module = ?MODULE, data = Port}) ->
+    call_port(Port, <<?RAM_FILE_FDATASYNC>>).
 
 sync(#file_descriptor{module = ?MODULE, data = Port}) -> 
     call_port(Port, <<?RAM_FILE_FSYNC>>).
@@ -349,6 +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}.
+
 
 
 %%%-----------------------------------------------------------------