From 56076c3080022f595541932fb4cea379939ec313 Mon Sep 17 00:00:00 2001 From: Joe Tsai Date: Sat, 4 Mar 2023 19:53:14 -0800 Subject: [PATCH] io: reduce allocations in Pipe constructor Rather than having PipeWriter and PipeReader a wrapper type on pipe, make them have the same underlying memory representation and rely instead of simply casting the same *pipe pointer as either a *PipeReader or *PipeWriter to control the set of methods. This reduces the number of allocations by 2, going from a total of 6 down to 4 allocations. Change-Id: I09207a00c4b7afb44c7773d752c5628a07e24fda Reviewed-on: https://go-review.googlesource.com/c/go/+/473535 Reviewed-by: Ian Lance Taylor Run-TryBot: Joseph Tsai Reviewed-by: Bryan Mills TryBot-Result: Gopher Robot --- src/io/pipe.go | 22 +++++++++------------- 1 file changed, 9 insertions(+), 13 deletions(-) diff --git a/src/io/pipe.go b/src/io/pipe.go index 2724e3f7ab..ae8322ee7b 100644 --- a/src/io/pipe.go +++ b/src/io/pipe.go @@ -123,9 +123,7 @@ func (p *pipe) writeCloseError() error { } // A PipeReader is the read half of a pipe. -type PipeReader struct { - p *pipe -} +type PipeReader struct{ pipe } // Read implements the standard Read interface: // it reads data from the pipe, blocking until a writer @@ -133,7 +131,7 @@ type PipeReader struct { // If the write end is closed with an error, that error is // returned as err; otherwise err is EOF. func (r *PipeReader) Read(data []byte) (n int, err error) { - return r.p.read(data) + return r.pipe.read(data) } // Close closes the reader; subsequent writes to the @@ -148,13 +146,11 @@ func (r *PipeReader) Close() error { // CloseWithError never overwrites the previous error if it exists // and always returns nil. func (r *PipeReader) CloseWithError(err error) error { - return r.p.closeRead(err) + return r.pipe.closeRead(err) } // A PipeWriter is the write half of a pipe. -type PipeWriter struct { - p *pipe -} +type PipeWriter struct{ r PipeReader } // Write implements the standard Write interface: // it writes data to the pipe, blocking until one or more readers @@ -162,7 +158,7 @@ type PipeWriter struct { // If the read end is closed with an error, that err is // returned as err; otherwise err is ErrClosedPipe. func (w *PipeWriter) Write(data []byte) (n int, err error) { - return w.p.write(data) + return w.r.pipe.write(data) } // Close closes the writer; subsequent reads from the @@ -178,7 +174,7 @@ func (w *PipeWriter) Close() error { // CloseWithError never overwrites the previous error if it exists // and always returns nil. func (w *PipeWriter) CloseWithError(err error) error { - return w.p.closeWrite(err) + return w.r.pipe.closeWrite(err) } // Pipe creates a synchronous in-memory pipe. @@ -197,10 +193,10 @@ func (w *PipeWriter) CloseWithError(err error) error { // Parallel calls to Read and parallel calls to Write are also safe: // the individual calls will be gated sequentially. func Pipe() (*PipeReader, *PipeWriter) { - p := &pipe{ + pw := &PipeWriter{r: PipeReader{pipe: pipe{ wrCh: make(chan []byte), rdCh: make(chan int), done: make(chan struct{}), - } - return &PipeReader{p}, &PipeWriter{p} + }}} + return &pw.r, pw } -- 2.48.1