Add support for Message(::Memory) on Julia 1.11

This is necessary because `IOBuffer.data` changed to being a `Memory` in
1.11. Also added a bunch of tests to cover the untested `Message`
constructors (which is how this wasn't caught earlier). Found with JET.jl.

docs/src/_changelog.md

@@ -7,6 +7,12 @@ CurrentModule = ZMQ
 This documents notable changes in ZMQ.jl. The format is based on [Keep a
 Changelog](https://keepachangelog.com).
 
+## Unreleased
+
+### Added
+- Support for creating [`Message`](@ref)'s from the new `Memory` type in Julia
+  1.11 ([#244]).
+
 ## [v1.2.6] - 2024-06-13
 
 ### Added

src/message.jl

@@ -103,12 +103,15 @@ mutable struct Message <: AbstractArray{UInt8,1}
         Message(p, pointer(p.string)+p.offset, sizeof(p))
 
     @doc """
-        Message(a::Array)
+        Message(a::T) where T <: DenseVector
 
     Create a message with an array as a buffer (for send). Note: the same
     ownership semantics as for [`Message(m::String)`](@ref) apply.
+
+    Usually `a` will be a 1D `Array`/`Vector`, but on 1.11+ it can also be a
+    `Memory`.
     """
-    Message(a::Array) = Message(a, pointer(a), sizeof(a))
+    Message(a::T) where T <: DenseVector = Message(a, pointer(a), sizeof(a))
 
     @doc """
         Message(io::IOBuffer)

test/runtests.jl

@@ -132,6 +132,63 @@ end
 
 	# ZMQ.close(s1); ZMQ.close(s2) # should happen when context is closed
 	ZMQ.close(ZMQ._context) # immediately close global context rather than waiting for exit
+    @test !isopen(s1)
+    @test !isopen(s2)
+end
+
+# Test all the send constructors
+@testset "Message" begin
+    s1 = Socket(PUB)
+    s2 = Socket(SUB)
+    ZMQ.subscribe(s2, "")
+	ZMQ.bind(s1, "tcp://*:5555")
+	ZMQ.connect(s2, "tcp://localhost:5555")
+
+    # Sleep for a bit to prevent the 'slow joiner' problem
+    sleep(0.5)
+
+    # Message(::Int) - construct from buffer size
+    data = rand(UInt8, 10)
+    m1 = Message(length(data))
+    # Note that we don't use copy!() for compatibility with Julia 1.3
+    for i in eachindex(data)
+        m1[i] = data[i]
+    end
+    ZMQ.send(s1, m1)
+    @test ZMQ.recv(s2) == data
+
+    # Message(::Any, ::Ptr, ::Int) - construct from pointer to existing data
+    buffer = rand(UInt8, 10)
+    m2 = Message(buffer, pointer(buffer), length(buffer))
+    ZMQ.send(s1, m2)
+    @test ZMQ.recv(s2) == buffer
+
+    # Message(::String)
+    str_msg = "foobar"
+    m3 = Message(str_msg)
+    ZMQ.send(s1, m3)
+    @test String(ZMQ.recv(s2)) == str_msg
+
+    # Message(::SubString)
+    m4 = Message(str_msg[1:3])
+    ZMQ.send(s1, m4)
+    @test String(ZMQ.recv(s2)) == str_msg[1:3]
+
+    # Message(::DenseVector) - construct from array
+    buffer2 = rand(UInt8, 10)
+    m5 = Message(buffer2)
+    ZMQ.send(s1, m5)
+    @test ZMQ.recv(s2) == buffer2
+
+    # Message(::IOBuffer)
+    buffer3 = rand(UInt8, 10)
+    iobuf = IOBuffer(buffer3)
+    m6 = Message(iobuf)
+    ZMQ.send(s1, m6)
+    @test ZMQ.recv(s2) == buffer3
+
+    close(s1)
+    close(s2)
 end
 
 @testset "ZMQ resource management" begin