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THRIFT-1021. ocaml: Framed transport support for OCaml

Patch: Richard Low

git-svn-id: https://svn.apache.org/repos/asf/thrift/trunk@1063917 13f79535-47bb-0310-9956-ffa450edef68
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1 parent 65ad14c commit 9dedce2196b511e50d39ca544dcf735d506d6d96 Bryan Duxbury committed Jan 26, 2011
Showing with 94 additions and 1 deletion.
  1. +1 −1 lib/ocaml/src/Makefile
  2. +93 −0 lib/ocaml/src/TFramedTransport.ml
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2 lib/ocaml/src/Makefile
@@ -17,7 +17,7 @@
# under the License.
#
-SOURCES = Thrift.ml TBinaryProtocol.ml TSocket.ml TChannelTransport.ml TServer.ml TSimpleServer.ml TServerSocket.ml TThreadedServer.ml
+SOURCES = Thrift.ml TBinaryProtocol.ml TSocket.ml TFramedTransport.ml TChannelTransport.ml TServer.ml TSimpleServer.ml TServerSocket.ml TThreadedServer.ml
RESULT = thrift
LIBS = unix threads
THREADS = yes
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93 lib/ocaml/src/TFramedTransport.ml
@@ -0,0 +1,93 @@
+open Thrift
+
+module T = Transport
+
+let c_0xff_32 = Int32.of_string "0xff"
+
+(* Copied from OCamlnet rtypes.ml *)
+let encode_frame_size x =
+ let s = String.create 4 in
+ let n3 = Int32.to_int (Int32.shift_right_logical x 24) land 0xff in
+ let n2 = Int32.to_int (Int32.shift_right_logical x 16) land 0xff in
+ let n1 = Int32.to_int (Int32.shift_right_logical x 8) land 0xff in
+ let n0 = Int32.to_int (Int32.logand x c_0xff_32) in
+ String.unsafe_set s 0 (Char.unsafe_chr n3);
+ String.unsafe_set s 1 (Char.unsafe_chr n2);
+ String.unsafe_set s 2 (Char.unsafe_chr n1);
+ String.unsafe_set s 3 (Char.unsafe_chr n0);
+ s
+
+let decode_frame_size s =
+ let n3 = Int32.of_int (Char.code s.[0]) in
+ let n2 = Int32.of_int (Char.code s.[1]) in
+ let n1 = Int32.of_int (Char.code s.[2]) in
+ let n0 = Int32.of_int (Char.code s.[3]) in
+ Int32.logor
+ (Int32.shift_left n3 24)
+ (Int32.logor
+ (Int32.shift_left n2 16)
+ (Int32.logor
+ (Int32.shift_left n1 8)
+ n0))
+
+class t ?(max_length=Sys.max_string_length) (transport: T.t) =
+object (self)
+ inherit T.t
+
+ method isOpen = transport#isOpen
+ method opn = transport#opn
+ method close = transport#close
+
+ val mutable read_buf = None
+ val mutable read_buf_offset = 0
+ val mutable write_buf = ""
+
+ method private read_frame =
+ let len_buf = String.create 4 in
+ assert (transport#readAll len_buf 0 4 = 4);
+
+ let size = Int32.to_int (decode_frame_size len_buf) in
+
+ (if size < 0
+ then failwith (Printf.sprintf "Read a negative frame size (%i)!" size));
+
+ (if size > max_length
+ then failwith (Printf.sprintf "Frame size (%i) larger than max length (%i)!" size max_length));
+
+ let buf = String.create size in
+ assert (transport#readAll buf 0 size = size);
+ read_buf <- Some buf;
+ read_buf_offset <- 0
+
+ method private read_from_frame frame buf off len =
+ let to_copy = min len ((String.length frame) - read_buf_offset) in
+ String.blit frame read_buf_offset buf off to_copy;
+ read_buf_offset <- read_buf_offset + to_copy;
+ to_copy
+
+ method read buf off len =
+ match read_buf with
+ | Some frame ->
+ let i = self#read_from_frame frame buf off len in
+ if i > 0
+ then i
+ else begin
+ self#read_frame;
+ self#read_from_frame frame buf off len
+ end
+ | None ->
+ self#read_frame;
+ self#read buf off len
+
+ method write buf off len =
+ write_buf <- write_buf ^ (String.sub buf off len)
+
+ method flush =
+ let encoded_size = encode_frame_size (Int32.of_int (String.length write_buf)) in
+ transport#write encoded_size 0 (String.length encoded_size);
+ transport#write write_buf 0 (String.length write_buf);
+ transport#flush;
+ write_buf <- ""
+end
+
+

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