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authorTuncer Ayaz <[email protected]>2011-01-13 12:36:14 +0100
committerLukas Larsson <[email protected]>2011-11-29 14:30:35 +0100
commit195e1f19b06095f39a4fb0da46dfab2ec5b10e9a (patch)
tree8f4a8c587b72c3a20d18b4cb6ccd7d1d52eb6286 /erts/preloaded/src/prim_file.erl
parent7292c3d9f5285592aa4de996f6f106cd365d7895 (diff)
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Implement file:sendfile
Allow Erlang code to use sendfile() where available by wrapping it as file:sendfile/4 and file:sendfile/2. sendfile(2) - Linux man page: "sendfile() copies data between one file descriptor and another. Because this copying is done within the kernel, sendfile() is more efficient than the combination of read(2) and write(2), which would require transferring data to and from user space."
Diffstat (limited to 'erts/preloaded/src/prim_file.erl')
-rw-r--r--erts/preloaded/src/prim_file.erl19
1 files changed, 18 insertions, 1 deletions
diff --git a/erts/preloaded/src/prim_file.erl b/erts/preloaded/src/prim_file.erl
index 30b7a5246a..f3f977a30b 100644
--- a/erts/preloaded/src/prim_file.erl
+++ b/erts/preloaded/src/prim_file.erl
@@ -26,7 +26,8 @@
%% Generic file contents operations
-export([open/2, close/1, datasync/1, sync/1, advise/4, position/2, truncate/1,
- write/2, pwrite/2, pwrite/3, read/2, read_line/1, pread/2, pread/3, copy/3]).
+ write/2, pwrite/2, pwrite/3, read/2, read_line/1, pread/2, pread/3,
+ copy/3, sendfile/5]).
%% Specialized file operations
-export([open/1, open/3]).
@@ -98,6 +99,7 @@
-define(FILE_READ_LINE, 29).
-define(FILE_FDATASYNC, 30).
-define(FILE_ADVISE, 31).
+-define(FILE_SENDFILE, 32).
%% Driver responses
-define(FILE_RESP_OK, 0).
@@ -539,6 +541,21 @@ write_file(_, _) ->
{error, badarg}.
+%% Returns {error, Reason} | {ok, BytesCopied}
+sendfile(#file_descriptor{module = ?MODULE, data = {Port, _}},
+ DestFD, Offset, Bytes, ChunkSize) ->
+ ok = drv_command(Port, <<?FILE_SENDFILE, DestFD:32, Offset:64, Bytes:64,
+ ChunkSize:64>>),
+ Self = self(),
+ %% Should we use a ref()?
+ receive
+ {efile_reply, Self, Port, {ok, _Written}=OKRes}->
+ OKRes;
+ {efile_reply, Self, Port, {error, _PosixError}=Error}->
+ Error;
+ Unexpected ->
+ Unexpected
+ end.
%%%-----------------------------------------------------------------
%%% Functions operating on files without handle to the file. ?DRV.