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authorDaniel Baumann <daniel.baumann@progress-linux.org>2024-04-16 19:25:22 +0000
committerDaniel Baumann <daniel.baumann@progress-linux.org>2024-04-16 19:25:22 +0000
commitf6ad4dcef54c5ce997a4bad5a6d86de229015700 (patch)
tree7cfa4e31ace5c2bd95c72b154d15af494b2bcbef /src/cmd/internal/bio
parentInitial commit. (diff)
downloadgolang-1.22-f6ad4dcef54c5ce997a4bad5a6d86de229015700.tar.xz
golang-1.22-f6ad4dcef54c5ce997a4bad5a6d86de229015700.zip
Adding upstream version 1.22.1.upstream/1.22.1
Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>
Diffstat (limited to 'src/cmd/internal/bio')
-rw-r--r--src/cmd/internal/bio/buf.go148
-rw-r--r--src/cmd/internal/bio/buf_mmap.go62
-rw-r--r--src/cmd/internal/bio/buf_nommap.go11
-rw-r--r--src/cmd/internal/bio/must.go43
4 files changed, 264 insertions, 0 deletions
diff --git a/src/cmd/internal/bio/buf.go b/src/cmd/internal/bio/buf.go
new file mode 100644
index 0000000..c4c2514
--- /dev/null
+++ b/src/cmd/internal/bio/buf.go
@@ -0,0 +1,148 @@
+// Copyright 2015 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+// Package bio implements common I/O abstractions used within the Go toolchain.
+package bio
+
+import (
+ "bufio"
+ "io"
+ "log"
+ "os"
+)
+
+// Reader implements a seekable buffered io.Reader.
+type Reader struct {
+ f *os.File
+ *bufio.Reader
+}
+
+// Writer implements a seekable buffered io.Writer.
+type Writer struct {
+ f *os.File
+ *bufio.Writer
+}
+
+// Create creates the file named name and returns a Writer
+// for that file.
+func Create(name string) (*Writer, error) {
+ f, err := os.Create(name)
+ if err != nil {
+ return nil, err
+ }
+ return &Writer{f: f, Writer: bufio.NewWriter(f)}, nil
+}
+
+// Open returns a Reader for the file named name.
+func Open(name string) (*Reader, error) {
+ f, err := os.Open(name)
+ if err != nil {
+ return nil, err
+ }
+ return NewReader(f), nil
+}
+
+// NewReader returns a Reader from an open file.
+func NewReader(f *os.File) *Reader {
+ return &Reader{f: f, Reader: bufio.NewReader(f)}
+}
+
+func (r *Reader) MustSeek(offset int64, whence int) int64 {
+ if whence == 1 {
+ offset -= int64(r.Buffered())
+ }
+ off, err := r.f.Seek(offset, whence)
+ if err != nil {
+ log.Fatalf("seeking in output: %v", err)
+ }
+ r.Reset(r.f)
+ return off
+}
+
+func (w *Writer) MustSeek(offset int64, whence int) int64 {
+ if err := w.Flush(); err != nil {
+ log.Fatalf("writing output: %v", err)
+ }
+ off, err := w.f.Seek(offset, whence)
+ if err != nil {
+ log.Fatalf("seeking in output: %v", err)
+ }
+ return off
+}
+
+func (r *Reader) Offset() int64 {
+ off, err := r.f.Seek(0, 1)
+ if err != nil {
+ log.Fatalf("seeking in output [0, 1]: %v", err)
+ }
+ off -= int64(r.Buffered())
+ return off
+}
+
+func (w *Writer) Offset() int64 {
+ if err := w.Flush(); err != nil {
+ log.Fatalf("writing output: %v", err)
+ }
+ off, err := w.f.Seek(0, 1)
+ if err != nil {
+ log.Fatalf("seeking in output [0, 1]: %v", err)
+ }
+ return off
+}
+
+func (r *Reader) Close() error {
+ return r.f.Close()
+}
+
+func (w *Writer) Close() error {
+ err := w.Flush()
+ err1 := w.f.Close()
+ if err == nil {
+ err = err1
+ }
+ return err
+}
+
+func (r *Reader) File() *os.File {
+ return r.f
+}
+
+func (w *Writer) File() *os.File {
+ return w.f
+}
+
+// Slice reads the next length bytes of r into a slice.
+//
+// This slice may be backed by mmap'ed memory. Currently, this memory
+// will never be unmapped. The second result reports whether the
+// backing memory is read-only.
+func (r *Reader) Slice(length uint64) ([]byte, bool, error) {
+ if length == 0 {
+ return []byte{}, false, nil
+ }
+
+ data, ok := r.sliceOS(length)
+ if ok {
+ return data, true, nil
+ }
+
+ data = make([]byte, length)
+ _, err := io.ReadFull(r, data)
+ if err != nil {
+ return nil, false, err
+ }
+ return data, false, nil
+}
+
+// SliceRO returns a slice containing the next length bytes of r
+// backed by a read-only mmap'd data. If the mmap cannot be
+// established (limit exceeded, region too small, etc) a nil slice
+// will be returned. If mmap succeeds, it will never be unmapped.
+func (r *Reader) SliceRO(length uint64) []byte {
+ data, ok := r.sliceOS(length)
+ if ok {
+ return data
+ }
+ return nil
+}
diff --git a/src/cmd/internal/bio/buf_mmap.go b/src/cmd/internal/bio/buf_mmap.go
new file mode 100644
index 0000000..65b245c
--- /dev/null
+++ b/src/cmd/internal/bio/buf_mmap.go
@@ -0,0 +1,62 @@
+// Copyright 2019 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+//go:build aix || darwin || dragonfly || freebsd || linux || netbsd || openbsd || solaris
+
+package bio
+
+import (
+ "runtime"
+ "sync/atomic"
+ "syscall"
+)
+
+// mmapLimit is the maximum number of mmaped regions to create before
+// falling back to reading into a heap-allocated slice. This exists
+// because some operating systems place a limit on the number of
+// distinct mapped regions per process. As of this writing:
+//
+// Darwin unlimited
+// DragonFly 1000000 (vm.max_proc_mmap)
+// FreeBSD unlimited
+// Linux 65530 (vm.max_map_count) // TODO: query /proc/sys/vm/max_map_count?
+// NetBSD unlimited
+// OpenBSD unlimited
+var mmapLimit int32 = 1<<31 - 1
+
+func init() {
+ // Linux is the only practically concerning OS.
+ if runtime.GOOS == "linux" {
+ mmapLimit = 30000
+ }
+}
+
+func (r *Reader) sliceOS(length uint64) ([]byte, bool) {
+ // For small slices, don't bother with the overhead of a
+ // mapping, especially since we have no way to unmap it.
+ const threshold = 16 << 10
+ if length < threshold {
+ return nil, false
+ }
+
+ // Have we reached the mmap limit?
+ if atomic.AddInt32(&mmapLimit, -1) < 0 {
+ atomic.AddInt32(&mmapLimit, 1)
+ return nil, false
+ }
+
+ // Page-align the offset.
+ off := r.Offset()
+ align := syscall.Getpagesize()
+ aoff := off &^ int64(align-1)
+
+ data, err := syscall.Mmap(int(r.f.Fd()), aoff, int(length+uint64(off-aoff)), syscall.PROT_READ, syscall.MAP_SHARED|syscall.MAP_FILE)
+ if err != nil {
+ return nil, false
+ }
+
+ data = data[off-aoff:]
+ r.MustSeek(int64(length), 1)
+ return data, true
+}
diff --git a/src/cmd/internal/bio/buf_nommap.go b/src/cmd/internal/bio/buf_nommap.go
new file mode 100644
index 0000000..674144e
--- /dev/null
+++ b/src/cmd/internal/bio/buf_nommap.go
@@ -0,0 +1,11 @@
+// Copyright 2019 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+//go:build !aix && !darwin && !dragonfly && !freebsd && !linux && !netbsd && !openbsd && !solaris
+
+package bio
+
+func (r *Reader) sliceOS(length uint64) ([]byte, bool) {
+ return nil, false
+}
diff --git a/src/cmd/internal/bio/must.go b/src/cmd/internal/bio/must.go
new file mode 100644
index 0000000..3604b29
--- /dev/null
+++ b/src/cmd/internal/bio/must.go
@@ -0,0 +1,43 @@
+// Copyright 2016 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package bio
+
+import (
+ "io"
+ "log"
+)
+
+// MustClose closes Closer c and calls log.Fatal if it returns a non-nil error.
+func MustClose(c io.Closer) {
+ if err := c.Close(); err != nil {
+ log.Fatal(err)
+ }
+}
+
+// MustWriter returns a Writer that wraps the provided Writer,
+// except that it calls log.Fatal instead of returning a non-nil error.
+func MustWriter(w io.Writer) io.Writer {
+ return mustWriter{w}
+}
+
+type mustWriter struct {
+ w io.Writer
+}
+
+func (w mustWriter) Write(b []byte) (int, error) {
+ n, err := w.w.Write(b)
+ if err != nil {
+ log.Fatal(err)
+ }
+ return n, nil
+}
+
+func (w mustWriter) WriteString(s string) (int, error) {
+ n, err := io.WriteString(w.w, s)
+ if err != nil {
+ log.Fatal(err)
+ }
+ return n, nil
+}