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author | Péter Szilágyi <peterke@gmail.com> | 2017-03-08 02:05:54 +0800 |
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committer | Felix Lange <fjl@users.noreply.github.com> | 2017-03-09 22:50:14 +0800 |
commit | 5c8fa6ae1a42813e7aec477bd68d98f66f85e0b8 (patch) | |
tree | 19e34d409d1a999079e007698f33766973676bc8 /vendor/github.com/edsrzf/mmap-go/mmap_windows.go | |
parent | b7d93500f13e3054c81196273ebf676ad8ecb5ba (diff) | |
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crypto, pow, vendor: hash optimizations, mmap ethash
Diffstat (limited to 'vendor/github.com/edsrzf/mmap-go/mmap_windows.go')
-rw-r--r-- | vendor/github.com/edsrzf/mmap-go/mmap_windows.go | 125 |
1 files changed, 125 insertions, 0 deletions
diff --git a/vendor/github.com/edsrzf/mmap-go/mmap_windows.go b/vendor/github.com/edsrzf/mmap-go/mmap_windows.go new file mode 100644 index 000000000..c3d2d02d3 --- /dev/null +++ b/vendor/github.com/edsrzf/mmap-go/mmap_windows.go @@ -0,0 +1,125 @@ +// Copyright 2011 Evan Shaw. 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 ( + "errors" + "os" + "sync" + "syscall" +) + +// mmap on Windows is a two-step process. +// First, we call CreateFileMapping to get a handle. +// Then, we call MapviewToFile to get an actual pointer into memory. +// Because we want to emulate a POSIX-style mmap, we don't want to expose +// the handle -- only the pointer. We also want to return only a byte slice, +// not a struct, so it's convenient to manipulate. + +// We keep this map so that we can get back the original handle from the memory address. +var handleLock sync.Mutex +var handleMap = map[uintptr]syscall.Handle{} + +func mmap(len int, prot, flags, hfile uintptr, off int64) ([]byte, error) { + flProtect := uint32(syscall.PAGE_READONLY) + dwDesiredAccess := uint32(syscall.FILE_MAP_READ) + switch { + case prot© != 0: + flProtect = syscall.PAGE_WRITECOPY + dwDesiredAccess = syscall.FILE_MAP_COPY + case prot&RDWR != 0: + flProtect = syscall.PAGE_READWRITE + dwDesiredAccess = syscall.FILE_MAP_WRITE + } + if prot&EXEC != 0 { + flProtect <<= 4 + dwDesiredAccess |= syscall.FILE_MAP_EXECUTE + } + + // The maximum size is the area of the file, starting from 0, + // that we wish to allow to be mappable. It is the sum of + // the length the user requested, plus the offset where that length + // is starting from. This does not map the data into memory. + maxSizeHigh := uint32((off + int64(len)) >> 32) + maxSizeLow := uint32((off + int64(len)) & 0xFFFFFFFF) + // TODO: Do we need to set some security attributes? It might help portability. + h, errno := syscall.CreateFileMapping(syscall.Handle(hfile), nil, flProtect, maxSizeHigh, maxSizeLow, nil) + if h == 0 { + return nil, os.NewSyscallError("CreateFileMapping", errno) + } + + // Actually map a view of the data into memory. The view's size + // is the length the user requested. + fileOffsetHigh := uint32(off >> 32) + fileOffsetLow := uint32(off & 0xFFFFFFFF) + addr, errno := syscall.MapViewOfFile(h, dwDesiredAccess, fileOffsetHigh, fileOffsetLow, uintptr(len)) + if addr == 0 { + return nil, os.NewSyscallError("MapViewOfFile", errno) + } + handleLock.Lock() + handleMap[addr] = h + handleLock.Unlock() + + m := MMap{} + dh := m.header() + dh.Data = addr + dh.Len = len + dh.Cap = dh.Len + + return m, nil +} + +func flush(addr, len uintptr) error { + errno := syscall.FlushViewOfFile(addr, len) + if errno != nil { + return os.NewSyscallError("FlushViewOfFile", errno) + } + + handleLock.Lock() + defer handleLock.Unlock() + handle, ok := handleMap[addr] + if !ok { + // should be impossible; we would've errored above + return errors.New("unknown base address") + } + + errno = syscall.FlushFileBuffers(handle) + return os.NewSyscallError("FlushFileBuffers", errno) +} + +func lock(addr, len uintptr) error { + errno := syscall.VirtualLock(addr, len) + return os.NewSyscallError("VirtualLock", errno) +} + +func unlock(addr, len uintptr) error { + errno := syscall.VirtualUnlock(addr, len) + return os.NewSyscallError("VirtualUnlock", errno) +} + +func unmap(addr, len uintptr) error { + flush(addr, len) + // Lock the UnmapViewOfFile along with the handleMap deletion. + // As soon as we unmap the view, the OS is free to give the + // same addr to another new map. We don't want another goroutine + // to insert and remove the same addr into handleMap while + // we're trying to remove our old addr/handle pair. + handleLock.Lock() + defer handleLock.Unlock() + err := syscall.UnmapViewOfFile(addr) + if err != nil { + return err + } + + handle, ok := handleMap[addr] + if !ok { + // should be impossible; we would've errored above + return errors.New("unknown base address") + } + delete(handleMap, addr) + + e := syscall.CloseHandle(syscall.Handle(handle)) + return os.NewSyscallError("CloseHandle", e) +} |