Add Transport:sendfile/4,/5

Adds offset based sendfile to transports. Same behaviour as
file:sendfile/4,/5 except socket and file arguments are reversed and
either a raw file or a filename can be used.

sendfile/2,/4,/5 now compulsory callbacks in ranch_transport.

ranch_tcp:sendfile/2 now defaults to a chunk_size of 8191 - the default
for ranch_ssl:sendfile/2. The same default is used for both
ranch_tcp:sendfile/4,5 and ranch_ssl:sendfile/4,5.

3 files changed, 174 insertions, 32 deletions

diff --git a/src/ranch_ssl.erl b/src/ranch_ssl.erl
index 98b2f5e..dfc5f11 100644
--- a/src/ranch_ssl.erl
+++ b/src/ranch_ssl.erl
@@ -34,6 +34,8 @@
 -export([recv/3]).
 -export([send/2]).
 -export([sendfile/2]).
+-export([sendfile/4]).
+-export([sendfile/5]).
 -export([setopts/2]).
 -export([controlling_process/2]).
 -export([peername/1]).
@@ -188,33 +190,32 @@ recv(Socket, Length, Timeout) ->
 send(Socket, Packet) ->
 	ssl:send(Socket, Packet).
 
-%% @doc Send a file on a socket.
+%% @equiv sendfile(Socket, Filename, 0, 0, [])
+-spec sendfile(ssl:sslsocket(), file:name_all())
+	-> {ok, non_neg_integer()} | {error, atom()}.
+sendfile(Socket, Filename) ->
+	sendfile(Socket, Filename, 0, 0, []).
+
+%% @equiv sendfile(Socket, File, Offset, Bytes, [])
+-spec sendfile(ssl:sslsocket(), file:name_all() | file:fd(),
+		non_neg_integer(), non_neg_integer())
+	-> {ok, non_neg_integer()} | {error, atom()}.
+sendfile(Socket, File, Offset, Bytes) ->
+	sendfile(Socket, File, Offset, Bytes, []).
+
+%% @doc Send part of a file on a socket.
 %%
 %% Unlike with TCP, no syscall can be used here, so sending files
-%% through SSL will be much slower in comparison.
+%% through SSL will be much slower in comparison. Note that unlike
+%% file:sendfile/5 this function accepts either a file or a file name.
 %%
-%% @see file:sendfile/2
--spec sendfile(ssl:sslsocket(), file:name())
+%% @see ranch_transport:sendfile/6
+%% @see file:sendfile/5
+-spec sendfile(ssl:sslsocket(), file:name_all() | file:fd(),
+		non_neg_integer(), non_neg_integer(), ranch_transport:sendfile_opts())
 	-> {ok, non_neg_integer()} | {error, atom()}.
-sendfile(Socket, Filepath) ->
-	{ok, IoDevice} = file:open(Filepath, [read, binary, raw]),
-	sendfile(Socket, IoDevice, 0).
-
--spec sendfile(ssl:sslsocket(), file:io_device(), non_neg_integer())
-	-> {ok, non_neg_integer()} | {error, atom()}.
-sendfile(Socket, IoDevice, Sent) ->
-	case file:read(IoDevice, 16#1FFF) of
-		eof ->
-			ok = file:close(IoDevice),
-			{ok, Sent};
-		{ok, Bin} ->
-			case send(Socket, Bin) of
-				ok ->
-					sendfile(Socket, IoDevice, Sent + byte_size(Bin));
-				{error, Reason} ->
-					{error, Reason}
-			end
-	end.
+sendfile(Socket, File, Offset, Bytes, Opts) ->
+	ranch_transport:sendfile(?MODULE, Socket, File, Offset, Bytes, Opts).
 
 %% @doc Set options on the given socket.
 %% @see ssl:setopts/2
diff --git a/src/ranch_tcp.erl b/src/ranch_tcp.erl
index 11a0843..6bdcdd0 100644
--- a/src/ranch_tcp.erl
+++ b/src/ranch_tcp.erl
@@ -28,6 +28,8 @@
 -export([recv/3]).
 -export([send/2]).
 -export([sendfile/2]).
+-export([sendfile/4]).
+-export([sendfile/5]).
 -export([setopts/2]).
 -export([controlling_process/2]).
 -export([peername/1]).
@@ -110,21 +112,52 @@ recv(Socket, Length, Timeout) ->
 send(Socket, Packet) ->
 	gen_tcp:send(Socket, Packet).
 
-%% @doc Send a file on a socket.
+%% @equiv sendfile(Socket, File, Offset, Bytes, [])
+-spec sendfile(inet:socket(), file:name_all())
+	-> {ok, non_neg_integer()} | {error, atom()}.
+sendfile(Socket, Filename) ->
+	sendfile(Socket, Filename, 0, 0, []).
+
+%% @equiv sendfile(Socket, File, Offset, Bytes, [])
+-spec sendfile(inet:socket(), file:name_all() | file:fd(), non_neg_integer(),
+		non_neg_integer())
+	-> {ok, non_neg_integer()} | {error, atom()}.
+sendfile(Socket, File, Offset, Bytes) ->
+	sendfile(Socket, File, Offset, Bytes, []).
+
+%% @doc Send part of a file on a socket.
 %%
-%% This is the optimal way to send files using TCP. It uses a syscall
-%% which means there is no context switch between opening the file
-%% and writing its contents on the socket.
+%% As with sendfile/2 this is the optimal way to send (parts) of files using
+%% TCP. Note that unlike file:sendfile/5 this function accepts either a raw file
+%% or a file name and the ordering of arguments is different.
 %%
-%% @see file:sendfile/2
--spec sendfile(inet:socket(), file:name())
+%% @see file:sendfile/5
+-spec sendfile(inet:socket(), file:name_all() | file:fd(), non_neg_integer(),
+		non_neg_integer(), [{chunk_size, non_neg_integer()}])
 	-> {ok, non_neg_integer()} | {error, atom()}.
-sendfile(Socket, Filename) ->
-	try file:sendfile(Filename, Socket) of
+sendfile(Socket, Filename, Offset, Bytes, Opts)
+		when is_list(Filename) orelse is_atom(Filename)
+		orelse is_binary(Filename) ->
+	case file:open(Filename, [read, raw, binary]) of
+		{ok, RawFile} ->
+			try sendfile(Socket, RawFile, Offset, Bytes, Opts) of
+				Result -> Result
+			after
+				ok = file:close(RawFile)
+			end;
+		{error, _} = Error ->
+			Error
+	end;
+sendfile(Socket, RawFile, Offset, Bytes, Opts) ->
+	Opts2 = case Opts of
+		[] -> [{chunk_size, 16#1FFF}];
+		_ -> Opts
+	end,
+	try file:sendfile(RawFile, Socket, Offset, Bytes, Opts2) of
 		Result -> Result
 	catch
 		error:{badmatch, {error, enotconn}} ->
-			%% file:sendfile/2 might fail by throwing a {badmatch, {error, enotconn}}
+			%% file:sendfile/5 might fail by throwing a {badmatch, {error, enotconn}}
 			%% this is because its internal implementation fails with a badmatch in
 			%% prim_file:sendfile/10 if the socket is not connected.
 			{error, closed}
diff --git a/src/ranch_transport.erl b/src/ranch_transport.erl
index 38dca5a..6168b35 100644
--- a/src/ranch_transport.erl
+++ b/src/ranch_transport.erl
@@ -15,8 +15,12 @@
 %% @private
 -module(ranch_transport).
 
+-export([sendfile/6]).
+
 -type socket() :: any().
 -type opts() :: any().
+-type sendfile_opts() :: [{chunk_size, non_neg_integer()}].
+-export_type([sendfile_opts/0]).
 
 %% Name of the transport.
 -callback name() -> atom().
@@ -55,6 +59,19 @@
 %% Send data on a socket.
 -callback send(socket(), iodata()) -> ok | {error, atom()}.
 
+%% Send a file on a socket.
+-callback sendfile(socket(), file:name())
+	-> {ok, non_neg_integer()} | {error, atom()}.
+
+%% Send part of a file on a socket.
+-callback sendfile(socket(), file:name() | file:fd(), non_neg_integer(),
+		non_neg_integer()) -> {ok, non_neg_integer()} | {error, atom()}.
+
+%% Send part of a file on a socket.
+-callback sendfile(socket(), file:name() | file:fd(), non_neg_integer(),
+		non_neg_integer(), sendfile_opts())
+	-> {ok, non_neg_integer()} | {error, atom()}.
+
 %% Set options on the given socket.
 -callback setopts(socket(), opts()) -> ok | {error, atom()}.
 
@@ -75,3 +92,94 @@
 
 %% Close the given socket.
 -callback close(socket()) -> ok.
+
+%% @doc Send part of a file on a socket.
+%%
+%% A fallback for transports that don't have a native sendfile implementation.
+%% Note that the ordering of arguments is different from file:sendfile/5 and
+%% that this function accepts either a raw file or a file name.
+%%
+%% @see file:sendfile/5
+-spec sendfile(module(), socket(), file:filename_all() | file:fd(),
+		non_neg_integer(), non_neg_integer(), sendfile_opts())
+	-> {ok, non_neg_integer()} | {error, atom()}.
+sendfile(Transport, Socket, Filename, Offset, Bytes, Opts)
+		when is_list(Filename) orelse is_atom(Filename)
+		orelse is_binary(Filename) ->
+	ChunkSize = chunk_size(Opts),
+	case file:open(Filename, [read, raw, binary]) of
+		{ok, RawFile} ->
+			_ = case Offset of
+				0 ->
+					ok;
+				_ ->
+					{ok, _} = file:position(RawFile, {bof, Offset})
+			end,
+			try
+				sendfile_loop(Transport, Socket, RawFile, Bytes, 0, ChunkSize)
+			after
+				ok = file:close(RawFile)
+			end;
+		{error, _Reason} = Error ->
+			Error
+	end;
+sendfile(Transport, Socket, RawFile, Offset, Bytes, Opts) ->
+	ChunkSize = chunk_size(Opts),
+	Initial2 = case file:position(RawFile, {cur, 0}) of
+		{ok, Offset} ->
+			Offset;
+		{ok, Initial} ->
+			{ok, _} = file:position(RawFile, {bof, Offset}),
+			Initial
+		end,
+	case sendfile_loop(Transport, Socket, RawFile, Bytes, 0, ChunkSize) of
+		{ok, _Sent} = Result ->
+			{ok, _} = file:position(RawFile, {bof, Initial2}),
+			Result;
+		{error, _Reason} = Error ->
+			Error
+	end.
+
+-spec chunk_size(sendfile_opts()) -> pos_integer().
+chunk_size(Opts) ->
+	case lists:keyfind(chunk_size, 1, Opts) of
+		{chunk_size, ChunkSize}
+				when is_integer(ChunkSize) andalso ChunkSize > 0 ->
+			ChunkSize;
+		{chunk_size, 0} ->
+			16#1FFF;
+		false ->
+			16#1FFF
+	end.
+
+-spec sendfile_loop(module(), socket(), file:fd(), non_neg_integer(),
+		non_neg_integer(), pos_integer())
+	-> {ok, non_neg_integer()} | {error, term()}.
+sendfile_loop(_Transport, _Socket, _RawFile, Sent, Sent, _ChunkSize)
+		when Sent =/= 0 ->
+	%% All requested data has been read and sent, return number of bytes sent.
+	{ok, Sent};
+sendfile_loop(Transport, Socket, RawFile, Bytes, Sent, ChunkSize) ->
+	ReadSize = read_size(Bytes, Sent, ChunkSize),
+	case file:read(RawFile, ReadSize) of
+		{ok, IoData} ->
+			case Transport:send(Socket, IoData) of
+				ok ->
+					Sent2 = iolist_size(IoData) + Sent,
+					sendfile_loop(Transport, Socket, RawFile, Bytes, Sent2,
+						ChunkSize);
+				{error, _Reason} = Error ->
+					Error
+			end;
+		eof ->
+			{ok, Sent};
+		{error, _Reason} = Error ->
+			Error
+	end.
+
+-spec read_size(non_neg_integer(), non_neg_integer(), non_neg_integer()) ->
+	non_neg_integer().
+read_size(0, _Sent, ChunkSize) ->
+	ChunkSize;
+read_size(Bytes, Sent, ChunkSize) ->
+	min(Bytes - Sent, ChunkSize).