79 lines
2.1 KiB
Go
79 lines
2.1 KiB
Go
package sysfs
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import (
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"fmt"
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"io/fs"
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"path"
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"syscall"
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"github.com/tetratelabs/wazero/internal/fsapi"
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)
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// Adapt adapts the input to fsapi.FS unless it is already one. Use NewDirFS instead
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// of os.DirFS as it handles interop issues such as windows support.
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//
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// Note: This performs no flag verification on OpenFile. fsapi.FS cannot read
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// flags as there is no parameter to pass them through with. Moreover, fsapi.FS
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// documentation does not require the file to be present. In summary, we can't
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// enforce flag behavior.
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func Adapt(fs fs.FS) fsapi.FS {
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if fs == nil {
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return fsapi.UnimplementedFS{}
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}
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if sys, ok := fs.(fsapi.FS); ok {
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return sys
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}
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return &adapter{fs: fs}
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}
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type adapter struct {
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fsapi.UnimplementedFS
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fs fs.FS
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}
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// String implements fmt.Stringer
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func (a *adapter) String() string {
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return fmt.Sprintf("%v", a.fs)
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}
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// OpenFile implements the same method as documented on fsapi.FS
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func (a *adapter) OpenFile(path string, flag int, perm fs.FileMode) (fsapi.File, syscall.Errno) {
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return OpenFSFile(a.fs, cleanPath(path), flag, perm)
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}
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// Stat implements the same method as documented on fsapi.FS
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func (a *adapter) Stat(path string) (fsapi.Stat_t, syscall.Errno) {
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f, errno := a.OpenFile(path, syscall.O_RDONLY, 0)
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if errno != 0 {
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return fsapi.Stat_t{}, errno
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}
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defer f.Close()
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return f.Stat()
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}
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// Lstat implements the same method as documented on fsapi.FS
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func (a *adapter) Lstat(path string) (fsapi.Stat_t, syscall.Errno) {
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// At this time, we make the assumption that fsapi.FS instances do not support
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// symbolic links, therefore Lstat is the same as Stat. This is obviously
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// not true but until fsapi.FS has a solid story for how to handle symlinks we
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// are better off not making a decision that would be difficult to revert
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// later on.
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//
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// For further discussions on the topic, see:
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// https://github.com/golang/go/issues/49580
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return a.Stat(path)
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}
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func cleanPath(name string) string {
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if len(name) == 0 {
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return name
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}
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// fs.ValidFile cannot be rooted (start with '/')
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cleaned := name
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if name[0] == '/' {
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cleaned = name[1:]
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}
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cleaned = path.Clean(cleaned) // e.g. "sub/." -> "sub"
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return cleaned
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}
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