make Request objects immutable

Author: simonbyrne

docs/src/reference/pointtopoint.md

@@ -4,7 +4,6 @@
 
 ```@docs
 MPI.Request
-MPI.RequestSet
 MPI.Status
 ```
 

src/collective.jl

@@ -29,10 +29,10 @@ If `comm` is an intercommunicator, then it blocks until all members of the other
 $(_doc_external("MPI_Ibarrier"))
 """
 function Ibarrier(comm::Comm)
-    req = Request()
+    rreq = Ref{MPI_Request}()
     # int MPI_Ibarrier(MPI_Comm comm, MPI_Req req)
-    @mpichk ccall((:MPI_Ibarrier, libmpi), Cint, (MPI_Comm, Ptr{MPI_Request}), comm, req)
-    return req
+    @mpichk ccall((:MPI_Ibarrier, libmpi), Cint, (MPI_Comm, Ptr{MPI_Request}), comm, rreq)
+    return Request(rreq[])
 end
 
 
@@ -911,7 +911,7 @@ function Neighbor_allgather!(sendbuf::Buffer, recvbuf::UBuffer, graph_comm::Comm
                 (MPIPtr, Cint, MPI_Datatype, MPIPtr, Cint, MPI_Datatype, MPI_Comm),
                 sendbuf.data, sendbuf.count, sendbuf.datatype,
                 recvbuf.data, recvbuf.count, recvbuf.datatype, graph_comm) v"3.0"
-    
+
     return recvbuf.data
 end
 Neighbor_allgather!(sendbuf, recvbuf::UBuffer, graph_comm::Comm) =

src/nonblocking.jl

@@ -53,31 +53,31 @@ checked by other means.
 
 See also [`Cancel!`](@ref).
 """
-mutable struct Request
+struct Request
     val::MPI_Request
-    buffer
 end
 Base.:(==)(a::Request, b::Request) = a.val == b.val
 Base.cconvert(::Type{MPI_Request}, request::Request) = request
 Base.unsafe_convert(::Type{MPI_Request}, request::Request) = request.val
-Base.unsafe_convert(::Type{Ptr{MPI_Request}}, request::Request) = convert(Ptr{MPI_Request}, pointer_from_objref(request))
+Base.cconvert(::Type{Ptr{MPI_Request}}, request::Request) = Ref(request.val)
 
-const REQUEST_NULL = Request(Consts.MPI_REQUEST_NULL[], nothing)
-add_load_time_hook!(() -> REQUEST_NULL.val = Consts.MPI_REQUEST_NULL[])
+@static if VERSION < v"1.8"
+    REQUEST_NULL = Request(Consts.MPI_REQUEST_NULL[])
+else
+    REQUEST_NULL::Request = Request(Consts.MPI_REQUEST_NULL[])
+end
+add_load_time_hook!(() -> global REQUEST_NULL = Request(Consts.MPI_REQUEST_NULL[]))
 
-Request() = Request(REQUEST_NULL.val, nothing)
 isnull(req::Request) = req == REQUEST_NULL
 
 function free(req::Request)
     if req != REQUEST_NULL && !MPI.Finalized()
         # int MPI_Request_free(MPI_Request *req)
         @mpichk ccall((:MPI_Request_free, libmpi), Cint, (Ptr{MPI_Request},), req)
     end
-    req.buffer = nothing
     return nothing
 end
 
-
 """
     status = Probe(src::Integer, tag::Integer, comm::Comm)
 
@@ -153,9 +153,6 @@ function Wait(req::Request, status::Union{Ref{Status}, Nothing}=nothing)
     @mpichk ccall((:MPI_Wait, libmpi), Cint,
                   (Ptr{MPI_Request}, MPIPtr),
                   req, something(status, Consts.MPI_STATUS_IGNORE[]))
-    if isnull(req) # only clear the buffer for non-persistent requests
-        req.buffer = nothing
-    end
     return nothing
 end
 function Wait(req::Request, ::Type{Status})
@@ -181,9 +178,6 @@ function Test(req::Request, status::Union{Ref{Status}, Nothing}=nothing)
     @mpichk ccall((:MPI_Test, libmpi), Cint,
                   (Ptr{MPI_Request}, Ptr{Cint}, Ptr{Status}),
                   req, flag, something(status, Consts.MPI_STATUS_IGNORE[]))
-    if isnull(req)
-        req.buffer = nothing
-    end
     return flag[] != 0
 end
 function Test(req::Request, ::Type{Status})
@@ -193,56 +187,6 @@ function Test(req::Request, ::Type{Status})
 end
 
 
-"""
-    RequestSet(requests::Vector{Request})
-
-A wrapper for an array of `Request`s that can be used to reduce intermediate memory
-allocations in [`Waitall`](@ref), [`Testall`](@ref), [`Waitany`](@ref), [`Testany`](@ref),
-[`Waitsome`](@ref) or [`Testsome`](@ref).
-
-"""
-mutable struct RequestSet <: AbstractVector{Request}
-    requests::Vector{Request}
-    vals::Vector{MPI_Request}
-end
-
-function RequestSet(requests::Vector{Request})
-    n = length(requests)
-    vals = Vector{MPI_Request}(undef, n)
-    for i = 1:n
-        vals[i] = requests[i].val
-    end
-    return RequestSet(requests, vals)
-end
-
-Base.length(reqs::RequestSet) = length(reqs.requests)
-Base.getindex(reqs::RequestSet, i::Integer) = reqs.requests[i]
-function Base.setindex!(reqs::RequestSet, req::Request, i::Integer)
-    reqs.vals[i] = req.val
-    reqs.requests[i] = req
-end
-
-function Base.push!(reqs::RequestSet, req::Request)
-    push!(reqs.vals, req.val)
-    push!(reqs.requests, req)
-end
-
-
-function update!(reqs::RequestSet, i::Integer)
-    req = reqs[i]
-    req.val = reqs.vals[i]
-    if isnull(req)
-        req.buffer = nothing
-    end
-end
-function update!(reqs::RequestSet)
-    n = length(reqs)
-    for i = 1:n
-        update!(reqs, i)
-    end
-end
-
-
 """
     Waitall(reqs::AbstractVector{Request}[, statuses::Vector{Status}])
     statuses = Waitall(reqs::AbstractVector{Request}, Status)
@@ -255,24 +199,22 @@ each request.
 # External links
 $(_doc_external("MPI_Waitall"))
 """
-function Waitall(reqs::RequestSet, statuses::Union{AbstractVector{Status},Nothing}=nothing)
+function Waitall(reqs::AbstractVector{Request}, statuses::Union{AbstractVector{Status},Nothing}=nothing)
     n = length(reqs)
     n == 0 && return nothing
     @assert isnothing(statuses) || length(statuses) >= n
     # int MPI_Waitall(int count, MPI_Request array_of_requests[],
     #                 MPI_Status array_of_statuses[])
     @mpichk ccall((:MPI_Waitall, libmpi), Cint,
                   (Cint, Ptr{MPI_Request}, Ptr{Status}),
-                  n, reqs.vals, something(statuses, Consts.MPI_STATUSES_IGNORE[]))
-    update!(reqs)
+                  n, reqs, something(statuses, Consts.MPI_STATUSES_IGNORE[]))
     return nothing
 end
-function Waitall(reqs::RequestSet, ::Type{Status})
+function Waitall(reqs::AbstractVector{Request}, ::Type{Status})
     statuses = Array{Status}(undef, length(reqs))
     Waitall(reqs, statuses)
     return statuses
 end
-Waitall(reqs::AbstractVector{Request}, args...) = Waitall(RequestSet(reqs), args...)
 
 
 """
@@ -289,24 +231,22 @@ each request.
 # External links
 $(_doc_external("MPI_Testall"))
 """
-function Testall(reqs::RequestSet, statuses::Union{AbstractVector{Status},Nothing}=nothing)
+function Testall(reqs::AbstractVector{Request}, statuses::Union{AbstractVector{Status},Nothing}=nothing)
     n = length(reqs)
     flag = Ref{Cint}()
     @assert isnothing(statuses) || length(statuses) >= n
     # int MPI_Testall(int count, MPI_Request array_of_requests[], int *flag,
     #                 MPI_Status array_of_statuses[])
     @mpichk ccall((:MPI_Testall, libmpi), Cint,
                   (Cint, Ptr{MPI_Request}, Ptr{Cint}, MPIPtr),
-                  n, reqs.vals, flag, something(statuses, Consts.MPI_STATUSES_IGNORE[]))
-    update!(reqs)
+                  n, reqs, flag, something(statuses, Consts.MPI_STATUSES_IGNORE[]))
     return flag[] != 0
 end
-function Testall(reqs::RequestSet, ::Type{Status})
+function Testall(reqs::AbstractVector{Request}, ::Type{Status})
     statuses = Array{Status}(undef, length(reqs))
     flag = Testall(reqs, statuses)
     return flag, statuses
 end
-Testall(reqs::Vector{Request}, args...) = Testall(RequestSet(reqs), args...)
 
 """
     i = Waitany(reqs::AbstractVector{Request}[, status::Ref{Status}])
@@ -323,28 +263,26 @@ The optional `status` argument can be used to obtain the return `Status` of the
 # External links
 $(_doc_external("MPI_Waitany"))
 """
-function Waitany(reqs::RequestSet, status::Union{Ref{Status}, Nothing}=nothing)
+function Waitany(reqs::AbstractVector{Request}, status::Union{Ref{Status}, Nothing}=nothing)
     ref_idx = Ref{Cint}()
     n = length(reqs)
     # int MPI_Waitany(int count, MPI_Request array_of_requests[], int *index,
     #                 MPI_Status *status)
     @mpichk ccall((:MPI_Waitany, libmpi), Cint,
                   (Cint, Ptr{MPI_Request}, Ptr{Cint}, MPIPtr),
-                  n, reqs.vals, ref_idx, something(status, Consts.MPI_STATUS_IGNORE[]))
+                  n, reqs, ref_idx, something(status, Consts.MPI_STATUS_IGNORE[]))
     idx = ref_idx[]
     if idx == Consts.MPI_UNDEFINED[]
         return nothing
     end
     i = Int(idx) + 1
-    update!(reqs, i)
     return i
 end
-function Waitany(reqs::RequestSet, ::Type{Status})
+function Waitany(reqs::AbstractVector{Request}, ::Type{Status})
     status = Ref(STATUS_ZERO)
     i = Waitany(reqs, status)
     return i, status[]
 end
-Waitany(reqs::Vector{Request}, args...) = Waitany(RequestSet(reqs), args...)
 
 """
     flag, idx = Testany(reqs::AbstractVector{Request}[, status::Ref{Status}])
@@ -364,31 +302,29 @@ The optional `status` argument can be used to obtain the return `Status` of the
 # External links
 $(_doc_external("MPI_Testany"))
 """
-function Testany(reqs::RequestSet, status::Union{Ref{Status}, Nothing}=nothing)
+function Testany(reqs::AbstractVector{Request}, status::Union{Ref{Status}, Nothing}=nothing)
     ref_idx = Ref{Cint}()
     rflag = Ref{Cint}()
     n = length(reqs)
     # int MPI_Testany(int count, MPI_Request array_of_requests[], int *index,
     #                 int *flag, MPI_Status *status)
     @mpichk ccall((:MPI_Testany, libmpi), Cint,
                   (Cint, Ptr{MPI_Request}, Ptr{Cint}, Ptr{Cint}, MPIPtr),
-                  n, reqs.vals, ref_idx, rflag, something(status, Consts.MPI_STATUS_IGNORE[]))
+                  n, reqs, ref_idx, rflag, something(status, Consts.MPI_STATUS_IGNORE[]))
     idx = ref_idx[]
     flag = rflag[] != 0
 
     if idx == Consts.MPI_UNDEFINED[]
         return flag, nothing
     end
     i = Int(idx) + 1
-    update!(reqs, i)
     return flag, i
 end
-function Testany(reqs::RequestSet, ::Type{Status})
+function Testany(reqs::AbstractVector{Request}, ::Type{Status})
     status = Ref(STATUS_ZERO)
     flag, i = Testany(reqs, status)
     return flag, i, status[]
 end
-Testany(reqs::Vector{Request}, args...) = Testany(RequestSet(reqs), args...)
 
 """
     inds = Waitsome(reqs::AbstractVector{Request}[, statuses::Vector{Status}])
@@ -404,7 +340,7 @@ completed request.
 # External links
 $(_doc_external("MPI_Waitsome"))
 """
-function Waitsome(reqs::RequestSet, statuses::Union{AbstractVector{Status},Nothing}=nothing)
+function Waitsome(reqs::AbstractVector{Request}, statuses::Union{AbstractVector{Status},Nothing}=nothing)
     ref_nout = Ref{Cint}()
     n = length(reqs)
     idxs = Vector{Cint}(undef, n)
@@ -415,22 +351,20 @@ function Waitsome(reqs::RequestSet, statuses::Union{AbstractVector{Status},Nothi
     #                  MPI_Status array_of_statuses[])
     @mpichk ccall((:MPI_Waitsome, libmpi), Cint,
           (Cint, Ptr{MPI_Request}, Ptr{Cint}, Ptr{Cint}, Ptr{Status}),
-          n, reqs.vals, ref_nout, idxs, something(statuses, Consts.MPI_STATUSES_IGNORE[]))
+          n, reqs, ref_nout, idxs, something(statuses, Consts.MPI_STATUSES_IGNORE[]))
     nout = Int(ref_nout[])
     # This can happen if there were no valid requests
     if nout == Consts.MPI_UNDEFINED[]
         return nothing
     end
-    update!(reqs)
     return [Int(idxs[i]) + 1 for i = 1:nout]
 end
-function Waitsome(reqs::RequestSet, ::Type{Status})
+function Waitsome(reqs::AbstractVector{Request}, ::Type{Status})
     statuses = Array{Status}(undef, length(reqs))
     inds = Waitsome(reqs, statuses)
     resize!(statuses, isnothing(inds) ? 0 : length(inds))
     return inds, statuses
 end
-Waitsome(reqs::Vector{Request}, args...) = Waitsome(RequestSet(reqs), args...)
 
 """
     inds = Testsome(reqs::AbstractVector{Request}[, statuses::Vector{Status}])
@@ -446,7 +380,7 @@ completed request.
 # External links
 $(_doc_external("MPI_Testsome"))
 """
-function Testsome(reqs::RequestSet, statuses::Union{AbstractVector{Status},Nothing}=nothing)
+function Testsome(reqs::AbstractVector{Request}, statuses::Union{AbstractVector{Status},Nothing}=nothing)
     ref_nout = Ref{Cint}()
     n = length(reqs)
     idxs = Vector{Cint}(undef, n)
@@ -457,22 +391,20 @@ function Testsome(reqs::RequestSet, statuses::Union{AbstractVector{Status},Nothi
     #                  MPI_Status array_of_statuses[])
     @mpichk ccall((:MPI_Testsome, libmpi), Cint,
                   (Cint, Ptr{MPI_Request}, Ptr{Cint}, Ptr{Cint}, Ptr{Status}),
-                  n, reqs.vals, ref_nout, idxs, something(statuses, Consts.MPI_STATUSES_IGNORE[]))
+                  n, reqs, ref_nout, idxs, something(statuses, Consts.MPI_STATUSES_IGNORE[]))
     nout = Int(ref_nout[])
     # This can happen if there were no valid requests
     if nout == Consts.MPI_UNDEFINED[]
         return nothing
     end
-    update!(reqs)
     return [Int(idxs[i]) + 1 for i = 1:nout]
 end
-function Testsome(reqs::RequestSet, ::Type{Status})
+function Testsome(reqs::AbstractVector{Request}, ::Type{Status})
     statuses = Array{Status}(undef, length(reqs))
     inds = Testsome(reqs, statuses)
     resize!(statuses, isnothing(inds) ? 0 : length(inds))
     return inds, statuses
 end
-Testsome(reqs::Vector{Request}, args...) = Testsome(RequestSet(reqs), args...)
 
 """
     Cancel!(req::Request)

src/pointtopoint.jl

@@ -62,15 +62,13 @@ Isend(data, comm::Comm; dest::Integer, tag::Integer=0) =
     Isend(data, dest, tag, comm)
 
 function Isend(buf::Buffer, dest::Integer, tag::Integer, comm::Comm)
-    req = Request()
+    rreq = Ref{MPI_Request}()
     # int MPI_Isend(const void* buf, int count, MPI_Datatype datatype, int dest,
     #               int tag, MPI_Comm comm, MPI_Request *request)
     @mpichk ccall((:MPI_Isend, libmpi), Cint,
           (MPIPtr, Cint, MPI_Datatype, Cint, Cint, MPI_Comm, Ptr{MPI_Request}),
-                  buf.data, buf.count, buf.datatype, dest, tag, comm, req)
-    req.buffer = buf
-    finalizer(free, req)
-    return req
+                  buf.data, buf.count, buf.datatype, dest, tag, comm, rreq)
+    return Request(rreq[])
 end
 Isend(data, dest::Integer, tag::Integer, comm::Comm) =
     Isend(Buffer_send(data), dest, tag, comm)
@@ -205,15 +203,13 @@ $(_doc_external("MPI_Irecv"))
 Irecv!(recvbuf, comm::Comm; source::Integer=Consts.MPI_ANY_SOURCE[], tag::Integer=Consts.MPI_ANY_TAG[]) =
     Irecv!(recvbuf, source, tag, comm)
 function Irecv!(buf::Buffer, source::Integer, tag::Integer, comm::Comm)
-    req = Request()
+    rreq = Ref{MPI_Request}()
     # int MPI_Irecv(void* buf, int count, MPI_Datatype datatype, int source,
     #               int tag, MPI_Comm comm, MPI_Request *request)
     @mpichk ccall((:MPI_Irecv, libmpi), Cint,
                   (MPIPtr, Cint, MPI_Datatype, Cint, Cint, MPI_Comm, Ptr{MPI_Request}),
-                  buf.data, buf.count, buf.datatype, source, tag, comm, req)
-    req.buffer = buf
-    finalizer(free, req)
-    return req
+                  buf.data, buf.count, buf.datatype, source, tag, comm, rreq)
+    return Request(rreq[])
 end
 Irecv!(data, source::Integer, tag::Integer, comm::Comm) =
     Irecv!(Buffer(data), source, tag, comm)