diff options
Diffstat (limited to 'src/cmd/go/internal/mmap')
-rw-r--r-- | src/cmd/go/internal/mmap/mmap.go | 31 | ||||
-rw-r--r-- | src/cmd/go/internal/mmap/mmap_other.go | 21 | ||||
-rw-r--r-- | src/cmd/go/internal/mmap/mmap_unix.go | 36 | ||||
-rw-r--r-- | src/cmd/go/internal/mmap/mmap_windows.go | 41 |
4 files changed, 129 insertions, 0 deletions
diff --git a/src/cmd/go/internal/mmap/mmap.go b/src/cmd/go/internal/mmap/mmap.go new file mode 100644 index 0000000..fcbd3e0 --- /dev/null +++ b/src/cmd/go/internal/mmap/mmap.go @@ -0,0 +1,31 @@ +// Copyright 2011 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. + +// This package is a lightly modified version of the mmap code +// in github.com/google/codesearch/index. + +// The mmap package provides an abstraction for memory mapping files +// on different platforms. +package mmap + +import ( + "os" +) + +// Data is mmap'ed read-only data from a file. +// The backing file is never closed, so Data +// remains valid for the lifetime of the process. +type Data struct { + f *os.File + Data []byte +} + +// Mmap maps the given file into memory. +func Mmap(file string) (Data, error) { + f, err := os.Open(file) + if err != nil { + return Data{}, err + } + return mmapFile(f) +} diff --git a/src/cmd/go/internal/mmap/mmap_other.go b/src/cmd/go/internal/mmap/mmap_other.go new file mode 100644 index 0000000..4d2844f --- /dev/null +++ b/src/cmd/go/internal/mmap/mmap_other.go @@ -0,0 +1,21 @@ +// Copyright 2022 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 (js && wasm) || wasip1 || plan9 + +package mmap + +import ( + "io" + "os" +) + +// mmapFile on other systems doesn't mmap the file. It just reads everything. +func mmapFile(f *os.File) (Data, error) { + b, err := io.ReadAll(f) + if err != nil { + return Data{}, err + } + return Data{f, b}, nil +} diff --git a/src/cmd/go/internal/mmap/mmap_unix.go b/src/cmd/go/internal/mmap/mmap_unix.go new file mode 100644 index 0000000..5dce872 --- /dev/null +++ b/src/cmd/go/internal/mmap/mmap_unix.go @@ -0,0 +1,36 @@ +// Copyright 2011 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 unix + +package mmap + +import ( + "fmt" + "io/fs" + "os" + "syscall" +) + +func mmapFile(f *os.File) (Data, error) { + st, err := f.Stat() + if err != nil { + return Data{}, err + } + size := st.Size() + pagesize := int64(os.Getpagesize()) + if int64(int(size+(pagesize-1))) != size+(pagesize-1) { + return Data{}, fmt.Errorf("%s: too large for mmap", f.Name()) + } + n := int(size) + if n == 0 { + return Data{f, nil}, nil + } + mmapLength := int(((size + pagesize - 1) / pagesize) * pagesize) // round up to page size + data, err := syscall.Mmap(int(f.Fd()), 0, mmapLength, syscall.PROT_READ, syscall.MAP_SHARED) + if err != nil { + return Data{}, &fs.PathError{Op: "mmap", Path: f.Name(), Err: err} + } + return Data{f, data[:n]}, nil +} diff --git a/src/cmd/go/internal/mmap/mmap_windows.go b/src/cmd/go/internal/mmap/mmap_windows.go new file mode 100644 index 0000000..d00bef7 --- /dev/null +++ b/src/cmd/go/internal/mmap/mmap_windows.go @@ -0,0 +1,41 @@ +// Copyright 2011 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 mmap + +import ( + "fmt" + "os" + "syscall" + "unsafe" + + "internal/syscall/windows" +) + +func mmapFile(f *os.File) (Data, error) { + st, err := f.Stat() + if err != nil { + return Data{}, err + } + size := st.Size() + if size == 0 { + return Data{f, nil}, nil + } + h, err := syscall.CreateFileMapping(syscall.Handle(f.Fd()), nil, syscall.PAGE_READONLY, 0, 0, nil) + if err != nil { + return Data{}, fmt.Errorf("CreateFileMapping %s: %w", f.Name(), err) + } + + addr, err := syscall.MapViewOfFile(h, syscall.FILE_MAP_READ, 0, 0, 0) + if err != nil { + return Data{}, fmt.Errorf("MapViewOfFile %s: %w", f.Name(), err) + } + var info windows.MemoryBasicInformation + err = windows.VirtualQuery(addr, &info, unsafe.Sizeof(info)) + if err != nil { + return Data{}, fmt.Errorf("VirtualQuery %s: %w", f.Name(), err) + } + data := unsafe.Slice((*byte)(unsafe.Pointer(addr)), int(info.RegionSize)) + return Data{f, data}, nil +} |