Make it possible again to read STDERR without calling cat

Merge the Pipe() and Pipe(C_NULL) constructors having the former just
call the latter and delaying initialization to the place where it is
actually needed. Now passing an empty Pipe to spawn will once again
initialize it with the appropriate pipe end.

base/exports.jl

@@ -1162,6 +1162,7 @@ export
     ntoh,
     open,
     pipe,
+    Pipe,
     PipeBuffer,
     poll_fd,
     poll_file,

base/process.jl

@@ -311,7 +311,9 @@ macro setup_stdio()
         in,out,err = stdios
         if isa(stdios[1], Pipe)
             if stdios[1].handle == C_NULL
-                error("pipes passed to spawn must be initialized")
+                in = box(Ptr{Void},Intrinsics.jl_alloca(_sizeof_uv_named_pipe))
+                link_pipe(in,false,stdios[1],true)
+                close_in = true
             end
         elseif isa(stdios[1], FileRedirect)
             in = FS.open(stdios[1].filename, JL_O_RDONLY)
@@ -321,7 +323,9 @@ macro setup_stdio()
         end
         if isa(stdios[2], Pipe)
             if stdios[2].handle == C_NULL
-                error("pipes passed to spawn must be initialized")
+                out = box(Ptr{Void},Intrinsics.jl_alloca(_sizeof_uv_named_pipe))
+                link_pipe(stdios[2],true,out,false)
+                close_out = true
             end
         elseif isa(stdios[2], FileRedirect)
             out = FS.open(stdios[2].filename, JL_O_WRONLY | JL_O_CREAT | (stdios[2].append?JL_O_APPEND:JL_O_TRUNC), S_IRUSR | S_IWUSR | S_IRGRP | S_IROTH)
@@ -331,7 +335,9 @@ macro setup_stdio()
         end
         if isa(stdios[3], Pipe)
             if stdios[3].handle == C_NULL
-                error("pipes passed to spawn must be initialized")
+                err = box(Ptr{Void},Intrinsics.jl_alloca(_sizeof_uv_named_pipe))
+                link_pipe(stdios[3],true,err,false)
+                close_err = true
             end
         elseif isa(stdios[3], FileRedirect)
             err = FS.open(stdios[3].filename, JL_O_WRONLY | JL_O_CREAT | (stdios[3].append?JL_O_APPEND:JL_O_TRUNC), S_IRUSR | S_IWUSR | S_IRGRP | S_IROTH)
@@ -345,9 +351,9 @@ end
 macro cleanup_stdio()
     esc(
     quote
-        close_in && close(in)
-        close_out && close(out)
-        close_err && close(err)
+        close_in && (isa(in,Ptr) ? close_pipe_sync(in) : close(in))
+        close_out && (isa(out,Ptr) ? close_pipe_sync(out) : close(out))
+        close_err && (isa(err,Ptr) ? close_pipe_sync(err) : close(err))
     end)
 end
 

base/socket.jl

@@ -343,7 +343,12 @@ _jl_sockaddr_set_port(ptr::Ptr{Void},port::UInt16) =
     ccall(:jl_sockaddr_set_port,Void,(Ptr{Void},UInt16),ptr,port)
 
 accept(server::TCPServer) = accept(server, TCPSocket())
-accept(server::PipeServer) = accept(server, Pipe())
+
+# Libuv will internally reset the readable and writable flags on
+# this pipe after it has successfully accepted the connection, to
+# remember that before that this is an invalid pipe
+accept(server::PipeServer) = accept(server, init_pipe!(Pipe();
+    readable=false, writable=false, julia_only=true))
 
 ##
 

base/stream.jl

@@ -128,18 +128,7 @@ type Pipe <: AsyncStream
         nothing, ReentrantLock(),
         DEFAULT_READ_BUFFER_SZ)
 end
-function Pipe()
-    handle = Libc.malloc(_sizeof_uv_named_pipe)
-    try
-        ret = Pipe(handle)
-        associate_julia_struct(ret.handle,ret)
-        finalizer(ret,uvfinalize)
-        return init_pipe!(ret;readable=true)
-    catch
-        Libc.free(handle)
-        rethrow()
-    end
-end
+Pipe() = Pipe(C_NULL)
 
 type PipeServer <: UVServer
     handle::Ptr{Void}
@@ -157,8 +146,9 @@ end
 
 function init_pipe!(pipe::Union{Pipe,PipeServer};readable::Bool=false,writable=false,julia_only=true)
     if pipe.handle == C_NULL
-        error("failed to initialize pipe")
-    elseif pipe.status != StatusUninit
+        malloc_julia_pipe!(pipe)
+    end
+    if pipe.status != StatusUninit
         error("pipe is already initialized")
     end
     uv_error("init_pipe",ccall(:jl_init_pipe, Cint, (Ptr{Void},Int32,Int32,Int32), pipe.handle, writable,readable,julia_only))
@@ -656,7 +646,7 @@ function process_events(block::Bool)
 end
 
 ## pipe functions ##
-function malloc_julia_pipe(x)
+function malloc_julia_pipe!(x)
     x.handle = Libc.malloc(_sizeof_uv_named_pipe)
     associate_julia_struct(x.handle,x)
     finalizer(x,uvfinalize)
@@ -680,7 +670,7 @@ end
 
 function link_pipe(read_end::Pipe,readable_julia_only::Bool,write_end::Ptr{Void},writable_julia_only::Bool)
     if read_end.handle == C_NULL
-        malloc_julia_pipe(read_end)
+        malloc_julia_pipe!(read_end)
     end
     init_pipe!(read_end; readable = true, writable = false, julia_only = readable_julia_only)
     uv_error("init_pipe",ccall(:jl_init_pipe, Cint, (Ptr{Void},Int32,Int32,Int32), write_end, 1, 0, writable_julia_only))
@@ -689,7 +679,7 @@ function link_pipe(read_end::Pipe,readable_julia_only::Bool,write_end::Ptr{Void}
 end
 function link_pipe(read_end::Ptr{Void},readable_julia_only::Bool,write_end::Pipe,writable_julia_only::Bool)
     if write_end.handle == C_NULL
-        malloc_julia_pipe(write_end)
+        malloc_julia_pipe!(write_end)
     end
     uv_error("init_pipe",ccall(:jl_init_pipe, Cint, (Ptr{Void},Int32,Int32,Int32), read_end, 0, 1, readable_julia_only))
     init_pipe!(write_end; readable = false, writable = true, julia_only = writable_julia_only)
@@ -698,10 +688,10 @@ function link_pipe(read_end::Ptr{Void},readable_julia_only::Bool,write_end::Pipe
 end
 function link_pipe(read_end::Pipe,readable_julia_only::Bool,write_end::Pipe,writable_julia_only::Bool)
     if write_end.handle == C_NULL
-        malloc_julia_pipe(write_end)
+        malloc_julia_pipe!(write_end)
     end
     if read_end.handle == C_NULL
-        malloc_julia_pipe(read_end)
+        malloc_julia_pipe!(read_end)
     end
     init_pipe!(read_end; readable = true, writable = false, julia_only = readable_julia_only)
     init_pipe!(write_end; readable = false, writable = true, julia_only = writable_julia_only)
@@ -965,7 +955,7 @@ function accept_nonblock(server::PipeServer,client::Pipe)
     err
 end
 function accept_nonblock(server::PipeServer)
-    client = Pipe()
+    client = init_pipe!(Pipe(); readable=true, writable=true, julia_only=true)
     uv_error("accept", accept_nonblock(server,client) != 0)
     client
 end
@@ -1035,7 +1025,9 @@ function connect(sock::AsyncStream, args...)
     sock
 end
 
-connect(path::AbstractString) = connect(Pipe(),path)
+# Libuv will internally reset read/writability, which is uses to
+# mark that this is an invalid pipe.
+connect(path::AbstractString) = connect(init_pipe!(Pipe(); readable=false, writable=false, julia_only=true),path)
 
 _fd(x::IOStream) = RawFD(fd(x))
 @unix_only _fd(x::AsyncStream) = RawFD(ccall(:jl_uv_handle,Int32,(Ptr{Void},),x.handle))

test/spawn.jl

@@ -174,6 +174,9 @@ if valgrind_off
     # If --trace-children=yes is passed to valgrind, we will get a
     # valgrind banner here, not "Hello World\n".
     @test readall(pipe(`$exename -f -e 'println(STDERR,"Hello World")'`, stderr=`cat`)) == "Hello World\n"
+    p = Pipe()
+    run(pipe(`$exename -f -e 'println(STDERR,"Hello World")'`, stderr = p))
+    @test readall(p) == "Hello World\n"
 end
 
 # issue #6310