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|
## Setting up the environment
```ocaml
# #require "eio_main";;
# #require "eio.mock";;
```
```ocaml
open Eio.Std
let run fn =
Eio_main.run @@ fun _ ->
fn ()
let mock_source =
let module X = struct
type t = Cstruct.t list ref
let read_methods = []
let single_read t buf =
match !t with
| [] -> raise End_of_file
| x :: xs ->
let len = min (Cstruct.length buf) (Cstruct.length x) in
Cstruct.blit x 0 buf 0 len;
t := Cstruct.shiftv (x :: xs) len;
len
end in
let ops = Eio.Flow.Pi.source (module X) in
fun items -> Eio.Resource.T (ref items, ops)
```
## read_exact
```ocaml
# run @@ fun () ->
let data = List.map Cstruct.of_string ["foo"; "bar"] in
let test n =
let buf = Cstruct.create n in
Eio.Flow.read_exact (mock_source data) buf;
traceln "Got %S" (Cstruct.to_string buf)
in
test 0;
test 3;
test 5;
test 6;
test 7;;
+Got ""
+Got "foo"
+Got "fooba"
+Got "foobar"
Exception: End_of_file.
```
## copy
```ocaml
# run @@ fun () ->
let src = Eio_mock.Flow.make "src" in
let dst = Eio_mock.Flow.make "dst" in
Eio_mock.Flow.on_read src [`Return "foo"; `Return "bar"];
Eio.Flow.copy src dst;;
+src: read "foo"
+dst: wrote "foo"
+src: read "bar"
+dst: wrote "bar"
- : unit = ()
```
Copying from a string src:
```ocaml
# run @@ fun () ->
let src = Eio.Flow.string_source "foobar" in
let dst = Eio_mock.Flow.make "dst" in
Eio_mock.Flow.on_copy_bytes dst [`Return 3; `Return 5];
Eio.Flow.copy src dst;;
+dst: wrote "foo"
+dst: wrote "bar"
- : unit = ()
```
Copying from src using a plain buffer (the default):
```ocaml
# run @@ fun () ->
let src = Eio.Flow.cstruct_source [Cstruct.of_string "foobar"] in
let dst = Eio_mock.Flow.make "dst" in
Eio_mock.Flow.on_copy_bytes dst [`Return 3; `Return 5];
Eio.Flow.copy src dst;;
+dst: wrote "foo"
+dst: wrote "bar"
- : unit = ()
```
Copying from src using `Read_source_buffer`:
```ocaml
# run @@ fun () ->
let src = Eio.Flow.cstruct_source [Cstruct.of_string "foobar"] in
let dst = Eio_mock.Flow.make "dst" in
Eio_mock.Flow.set_copy_method dst `Read_source_buffer;
Eio_mock.Flow.on_copy_bytes dst [`Return 3; `Return 5];
Eio.Flow.copy src dst;;
+dst: wrote (rsb) ["foo"]
+dst: wrote (rsb) ["bar"]
- : unit = ()
```
## read_all
```ocaml
# run @@ fun () ->
let each = String.init 256 Char.chr in
let data = List.init 40 (fun _ -> Cstruct.of_string each) in
let got = Eio.Flow.read_all (mock_source data) in
traceln "Input length: %d\nOutput length: %d\nEqual: %b"
(Cstruct.lenv data) (String.length got) (String.equal got (Cstruct.copyv data));
;;
+Input length: 10240
+Output length: 10240
+Equal: true
- : unit = ()
```
## write
```ocaml
# run @@ fun () ->
let dst = Eio_mock.Flow.make "dst" in
Eio_mock.Flow.on_copy_bytes dst [`Return 6];
Eio.Flow.write dst [Cstruct.of_string "foobar"];;
+dst: wrote "foobar"
- : unit = ()
```
## Pipes
Writing to and reading from a pipe.
```ocaml
# Eio_main.run @@ fun env ->
Switch.run @@ fun sw ->
let r, w = Eio_unix.pipe sw in
let msg = "Hello, world" in
Eio.Fiber.both
(fun () ->
let buf = Cstruct.create (String.length msg) in
let () = Eio.Flow.read_exact r buf in
traceln "Got: %s" (Cstruct.to_string buf)
)
(fun () ->
Eio.Flow.copy_string msg w;
Eio.Flow.close w
);;
+Got: Hello, world
- : unit = ()
```
Make sure we don't crash on SIGPIPE:
```ocaml
# Eio_main.run @@ fun env ->
Switch.run @@ fun sw ->
let r, w = Eio_unix.pipe sw in
Eio.Flow.close r;
try
Eio.Flow.copy_string "Test" w;
assert false
with Eio.Io (Eio.Net.E Connection_reset _, _) ->
traceln "Connection_reset (good)";;
+Connection_reset (good)
- : unit = ()
```
## IO_MAX
Sending a very long vector over a flow should just send it in chunks, not fail:
```ocaml
# Eio_main.run @@ fun env ->
Switch.run @@ fun sw ->
let r, w = Eio_unix.pipe sw in
let a = Cstruct.of_string "abc" in
let vecs = List.init 10_000 (Fun.const a) in
Fiber.both
(fun () ->
Eio.Flow.write w vecs;
Eio.Flow.close w
)
(fun () ->
let got = Eio.Flow.read_all r in
traceln "Read %d bytes" (String.length got);
assert (got = Cstruct.to_string (Cstruct.concat vecs))
)
+Read 30000 bytes
- : unit = ()
```
## Starvation
Even if a fiber is already ready to run, we still perform IO from time to time:
```ocaml
# run @@ fun _ ->
Switch.run @@ fun sw ->
let r, w = Eio_unix.pipe sw in
let rec spin () = Fiber.yield (); spin () in
Fiber.fork_daemon ~sw spin;
Fiber.both
(fun () ->
let buf = Cstruct.create 3 in
Eio.Flow.read_exact r buf;
traceln "Got %S" (Cstruct.to_string buf)
)
(fun () ->
Eio.Flow.write w [Cstruct.of_string "msg"]
)
+Got "msg"
- : unit = ()
```
|
