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package explicitfilepath
import (
"fmt"
"os"
"path/filepath"
"github.com/containers/storage/pkg/fileutils"
)
// ResolvePathToFullyExplicit returns the input path converted to an absolute, no-symlinks, cleaned up path.
// To do so, all elements of the input path must exist; as a special case, the final component may be
// a non-existent name (but not a symlink pointing to a non-existent name)
// This is intended as a helper for implementations of types.ImageReference.PolicyConfigurationIdentity etc.
func ResolvePathToFullyExplicit(path string) (string, error) {
switch err := fileutils.Lexists(path); {
case err == nil:
return resolveExistingPathToFullyExplicit(path)
case os.IsNotExist(err):
parent, file := filepath.Split(path)
resolvedParent, err := resolveExistingPathToFullyExplicit(parent)
if err != nil {
return "", err
}
if file == "." || file == ".." {
// Coverage: This can happen, but very rarely: if we have successfully resolved the parent, both "." and ".." in it should have been resolved as well.
// This can still happen if there is a filesystem race condition, causing the Lstat() above to fail but the later resolution to succeed.
// We do not care to promise anything if such filesystem race conditions can happen, but we definitely don't want to return "."/".." components
// in the resulting path, and especially not at the end.
return "", fmt.Errorf("Unexpectedly missing special filename component in %s", path)
}
resolvedPath := filepath.Join(resolvedParent, file)
// As a sanity check, ensure that there are no "." or ".." components.
cleanedResolvedPath := filepath.Clean(resolvedPath)
if cleanedResolvedPath != resolvedPath {
// Coverage: This should never happen.
return "", fmt.Errorf("Internal inconsistency: Path %s resolved to %s still cleaned up to %s", path, resolvedPath, cleanedResolvedPath)
}
return resolvedPath, nil
default: // err != nil, unrecognized
return "", err
}
}
// resolveExistingPathToFullyExplicit is the same as ResolvePathToFullyExplicit,
// but without the special case for missing final component.
func resolveExistingPathToFullyExplicit(path string) (string, error) {
resolved, err := filepath.Abs(path)
if err != nil {
return "", err // Coverage: This can fail only if os.Getwd() fails.
}
resolved, err = filepath.EvalSymlinks(resolved)
if err != nil {
return "", err
}
return filepath.Clean(resolved), nil
}
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