319d6cca62
This reduces some boilerplate by extracting UnimplementedFS from the existing FS implementations, such that it returns ENOSYS. This also removes inconsistency where some methods on FS returned syscall.Errno and others PathError. Note: this doesn't get rid of all PathError, yet. We still need to create a syscallfs.File type which would be able to do that. This is just one preliminary cleanup before refactoring out the `fs.FS` embedding from `syscallfs.DS`. P.S. naming convention is arbitrary, so I took UnimplementedXXX from grpc. This pattern is used a lot of places, also proxy-wasm-go-sdk, e.g. `DefaultVMContext`. Signed-off-by: Adrian Cole <adrian@tetrate.io>
66 lines
1.5 KiB
Go
66 lines
1.5 KiB
Go
package syscallfs
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import (
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"fmt"
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"io/fs"
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"os"
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pathutil "path"
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)
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// Adapt adapts the input to FS unless it is already one. NewDirFS should be
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// used instead, if the input is os.DirFS.
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//
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// Note: This performs no flag verification on FS.OpenFile. fs.FS cannot read
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// flags as there is no parameter to pass them through with. Moreover, fs.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, guestDir string) FS {
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if sys, ok := fs.(FS); ok {
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return sys
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}
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return &adapter{fs: fs, guestDir: guestDir}
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}
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type adapter struct {
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UnimplementedFS
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fs fs.FS
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guestDir string
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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:%s:ro", a.fs, a.guestDir)
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}
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// GuestDir implements FS.GuestDir
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func (a *adapter) GuestDir() string {
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return a.guestDir
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}
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// OpenFile implements FS.OpenFile
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func (a *adapter) OpenFile(path string, flag int, perm fs.FileMode) (fs.File, error) {
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path = cleanPath(path)
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f, err := a.fs.Open(path)
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if err != nil {
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return nil, unwrapPathError(err)
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} else if osF, ok := f.(*os.File); ok {
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// If this is an OS file, it has same portability issues as dirFS.
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return maybeWrapFile(osF), nil
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}
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return f, nil
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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 = pathutil.Clean(cleaned) // e.g. "sub/." -> "sub"
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return cleaned
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}
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