Writer

Basic Operation of Writers

Having launched, a Writer is triggered through its trigger pin. When triggered, a Writer reads its input and then writes it to its internal buffer databuf. When databuf is full, the data in databuf is processed. Thus, the length of the data that is to be processed by the Writer is determined by the length of their internal buffer databuf.

Let us construct a Writer.

julia> using Causal # hide

julia> w = Writer(input=Inport(), buflen=5)
Writer(path:/tmp/cba80d8a-452c-4b5b-9411-7fb6e2f22f4b.jld2, nin:1)

The file of w is closed and the trigger pin of w is not writable. That is, it is not possible to trigger w from its trigger pin.

julia> w.file
JLDFile /tmp/cba80d8a-452c-4b5b-9411-7fb6e2f22f4b.jld2 (read/write)
  (closed)

julia> w.trigger
Inpin(eltype:Float64, isbound:false)

To trigger w, we need to open and launch it,

julia> oport, trg, hnd = Outport(), Outpin(), Inpin{Bool}()
(Outport(numpins:1, eltype:Outpin{Float64}), Outpin(eltype:Float64, isbound:false), Inpin(eltype:Bool, isbound:false))

julia> connect!(oport, w.input)
1-element Array{Link{Float64},1}:
 Link(state:open, eltype:Float64, isreadable:false, iswritable:false)

julia> connect!(trg, w.trigger)
Link(state:open, eltype:Float64, isreadable:false, iswritable:false)

julia> connect!(w.handshake, hnd)
Link(state:open, eltype:Bool, isreadable:false, iswritable:false)

julia> open(w)
Writer(path:/tmp/cba80d8a-452c-4b5b-9411-7fb6e2f22f4b.jld2, nin:1)

julia> t = launch(w)
Task (runnable) @0x00007f1fcfb25390

Now, the internal file of w is opened in read/write mode and its trigger pin is writable.

julia> w.file
JLDFile /tmp/cba80d8a-452c-4b5b-9411-7fb6e2f22f4b.jld2 (read/write)
  (no datasets)

julia> w.trigger.link
Link(state:open, eltype:Float64, isreadable:false, iswritable:true)

Let us now trigger w.

julia> put!(trg, 1.)

The input of w is now readable and handshake pin is not readable since w have not signaled that its triggering is succeeded yet. To do that, we need to put a value to the input of w

julia> put!(oport, [10.])
1-element Array{Float64,1}:
 10.0

Now, w signalled that its step is succeeded. It read the data from its input and written it into is databuf.

julia> hnd.link
Link(state:open, eltype:Bool, isreadable:true, iswritable:false)

julia> take!(hnd)
true

julia> w.databuf
5-element Buffer{Cyclic,Float64,1}:
 10.0
  0.0
  0.0
  0.0
  0.0

Since the databuf is not full nothing is written to the file of w.

julia> w.file
JLDFile /tmp/cba80d8a-452c-4b5b-9411-7fb6e2f22f4b.jld2 (read/write)
  (no datasets)

Let us continue triggering w until the databuf of w is full.

julia> for t in 2. : 5.
           put!(trg, t)
           put!(oport, [t * 10])
           take!(hnd)
       end

Now check that the content of the file of w.

julia> w.file
JLDFile /tmp/cba80d8a-452c-4b5b-9411-7fb6e2f22f4b.jld2 (read/write)
 └─🔢 [5.0, 4.0, 3.0, 2.0, 1.0]

Note that the content of databuf is written to the file of w. The operation of w can be terminated.

julia> put!(trg, NaN)

When terminated, the file of w is closed.

julia> w.file
JLDFile /tmp/cba80d8a-452c-4b5b-9411-7fb6e2f22f4b.jld2 (read/write)
  (closed)

Full API

mutable struct Writer{A, FL, var"253", var"254", var"255", Symbol, var"256", var"263", Int, var"264", var"265", var"266", var"267"} <: AbstractSink

write!(writer, td, xd)

julia> w = Writer(Inport(1))
Writer(path:/tmp/e907d6ad-8db2-4c4a-9959-5b8d33d32156.jld2, nin:1)

julia> open(w)
Writer(path:/tmp/e907d6ad-8db2-4c4a-9959-5b8d33d32156.jld2, nin:1)

julia> write!(w, 0., 10.)
10.0

julia> write!(w, 1., 20.)
20.0

julia> w.file
JLDFile /tmp/e907d6ad-8db2-4c4a-9959-5b8d33d32156.jld2 (read/write)
 ├─🔢 0.0
 └─🔢 1.0

julia> w.file[string(0.)]
10.0

read(writer; flatten)

fread(path; flatten)

mv(writer, dst; force)

julia> mkdir(joinpath(tempdir(), "testdir1"))
"/tmp/testdir1"

julia> mkdir(joinpath(tempdir(), "testdir2"))
"/tmp/testdir2"

julia> w = Writer(Inport(), path="/tmp/testdir1/myfile.jld2")
Writer(path:/tmp/testdir1/myfile.jld2, nin:1)

julia> mv(w, "/tmp/testdir2")
Writer(path:/tmp/testdir2/myfile.jld2, nin:1)

cp(writer, dst; force, follow_symlinks)

julia> mkdir(joinpath(tempdir(), "testdir1"))
"/tmp/testdir1"

julia> mkdir(joinpath(tempdir(), "testdir2"))
"/tmp/testdir2"

julia> w = Writer(Inport(), path="/tmp/testdir1")
Writer(path:/tmp/testdir1.jld2, nin:1)

julia> cp(w, "/tmp/testdir2")
Writer(path:/tmp/testdir2/1e72bad1-9800-4ca0-bccd-702afe75e555, nin:1)

open(writer)
open(writer, mode)

close(writer)