mirror of
https://github.com/hanzoai/visor.git
synced 2026-09-24 17:04:14 +00:00
Michael PrattandgVisor bot
fd92eddce9
Accessing a pointer to the data in a slice can be achieved with
`unsafe.Pointer(&slice[0])`.
347e062d3b motivated using gohacks.SliceHeader in
this way with "we often use SliceHeader to extract pointers from slices in a
way that avoids bounds checking and/or handles nil slices correctly", but this
no longer seems to be the case. None of the remaining uses are obviously
performance sensitive or necessarily include bounds checks, nor get used with
nil slices.
This brings us one step closer to removing gohacks.SliceHeader, which is one
less internal detail to keep in sync with Go.
For #8422
PiperOrigin-RevId: 504408578
34 lines
1.1 KiB
Go
34 lines
1.1 KiB
Go
// Copyright 2022 The gVisor Authors.
|
|
//
|
|
// Licensed under the Apache License, Version 2.0 (the "License");
|
|
// you may not use this file except in compliance with the License.
|
|
// You may obtain a copy of the License at
|
|
//
|
|
// http://www.apache.org/licenses/LICENSE-2.0
|
|
//
|
|
// Unless required by applicable law or agreed to in writing, software
|
|
// distributed under the License is distributed on an "AS IS" BASIS,
|
|
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
|
|
// See the License for the specific language governing permissions and
|
|
// limitations under the License.
|
|
|
|
package iouringfs
|
|
|
|
import (
|
|
"fmt"
|
|
"unsafe"
|
|
|
|
"gvisor.dev/gvisor/pkg/atomicbitops"
|
|
)
|
|
|
|
func atomicUint32AtOffset(buf []byte, offset int) *atomicbitops.Uint32 {
|
|
const sizeOfUint32 int = 4
|
|
if offset+sizeOfUint32 > len(buf) || offset < 0 {
|
|
panic(fmt.Sprintf("cast at offset %d for slice of len %d would result in overrun", offset, len(buf)))
|
|
}
|
|
if offset%sizeOfUint32 != 0 {
|
|
panic(fmt.Sprintf("cast at offset %d would produce unaligned pointer", offset))
|
|
}
|
|
return (*atomicbitops.Uint32)(unsafe.Pointer(&buf[offset]))
|
|
}
|