1 files changed, 113 insertions, 0 deletions
diff --git a/cli/internal/fs/path.go b/cli/internal/fs/path.go
new file mode 100644
index 0000000..2023d69
--- /dev/null
+++ b/cli/internal/fs/path.go
@@ -0,0 +1,113 @@
+package fs
+
+import (
+	"fmt"
+	iofs "io/fs"
+	"os"
+	"path/filepath"
+	"reflect"
+
+	"github.com/adrg/xdg"
+	"github.com/vercel/turbo/cli/internal/turbopath"
+)
+
+// CheckedToAbsoluteSystemPath inspects a string and determines if it is an absolute path.
+func CheckedToAbsoluteSystemPath(s string) (turbopath.AbsoluteSystemPath, error) {
+	if filepath.IsAbs(s) {
+		return turbopath.AbsoluteSystemPath(s), nil
+	}
+	return "", fmt.Errorf("%v is not an absolute path", s)
+}
+
+// ResolveUnknownPath returns unknown if it is an absolute path, otherwise, it
+// assumes unknown is a path relative to the given root.
+func ResolveUnknownPath(root turbopath.AbsoluteSystemPath, unknown string) turbopath.AbsoluteSystemPath {
+	if filepath.IsAbs(unknown) {
+		return turbopath.AbsoluteSystemPath(unknown)
+	}
+	return root.UntypedJoin(unknown)
+}
+
+// UnsafeToAbsoluteSystemPath directly converts a string to an AbsoluteSystemPath
+func UnsafeToAbsoluteSystemPath(s string) turbopath.AbsoluteSystemPath {
+	return turbopath.AbsoluteSystemPath(s)
+}
+
+// UnsafeToAnchoredSystemPath directly converts a string to an AbsoluteSystemPath
+func UnsafeToAnchoredSystemPath(s string) turbopath.AnchoredSystemPath {
+	return turbopath.AnchoredSystemPath(s)
+}
+
+// AbsoluteSystemPathFromUpstream is used to mark return values from APIs that we
+// expect to give us absolute paths. No checking is performed.
+// Prefer to use this over a cast to maintain the search-ability of interfaces
+// into and out of the turbopath.AbsoluteSystemPath type.
+func AbsoluteSystemPathFromUpstream(s string) turbopath.AbsoluteSystemPath {
+	return turbopath.AbsoluteSystemPath(s)
+}
+
+// GetCwd returns the calculated working directory after traversing symlinks.
+func GetCwd(cwdRaw string) (turbopath.AbsoluteSystemPath, error) {
+	if cwdRaw == "" {
+		var err error
+		cwdRaw, err = os.Getwd()
+		if err != nil {
+			return "", err
+		}
+	}
+	// We evaluate symlinks here because the package managers
+	// we support do the same.
+	cwdRaw, err := filepath.EvalSymlinks(cwdRaw)
+	if err != nil {
+		return "", fmt.Errorf("evaluating symlinks in cwd: %w", err)
+	}
+	cwd, err := CheckedToAbsoluteSystemPath(cwdRaw)
+	if err != nil {
+		return "", fmt.Errorf("cwd is not an absolute path %v: %v", cwdRaw, err)
+	}
+	return cwd, nil
+}
+
+// GetVolumeRoot returns the root directory given an absolute path.
+func GetVolumeRoot(absolutePath string) string {
+	return filepath.VolumeName(absolutePath) + string(os.PathSeparator)
+}
+
+// CreateDirFSAtRoot creates an `os.dirFS` instance at the root of the
+// volume containing the specified path.
+func CreateDirFSAtRoot(absolutePath string) iofs.FS {
+	return os.DirFS(GetVolumeRoot(absolutePath))
+}
+
+// GetDirFSRootPath returns the root path of a os.dirFS.
+func GetDirFSRootPath(fsys iofs.FS) string {
+	// We can't typecheck fsys to enforce using an `os.dirFS` because the
+	// type isn't exported from `os`. So instead, reflection. 🤷‍♂️
+
+	fsysType := reflect.TypeOf(fsys).Name()
+	if fsysType != "dirFS" {
+		// This is not a user error, fail fast
+		panic("GetDirFSRootPath must receive an os.dirFS")
+	}
+
+	// The underlying type is a string; this is the original path passed in.
+	return reflect.ValueOf(fsys).String()
+}
+
+// IofsRelativePath calculates a `os.dirFS`-friendly path from an absolute system path.
+func IofsRelativePath(fsysRoot string, absolutePath string) (string, error) {
+	return filepath.Rel(fsysRoot, absolutePath)
+}
+
+// TempDir returns the absolute path of a directory with the given name
+// under the system's default temp directory location
+func TempDir(subDir string) turbopath.AbsoluteSystemPath {
+	return turbopath.AbsoluteSystemPath(os.TempDir()).UntypedJoin(subDir)
+}
+
+// GetUserConfigDir returns the platform-specific common location
+// for configuration files that belong to a user.
+func GetUserConfigDir() turbopath.AbsoluteSystemPath {
+	configHome := AbsoluteSystemPathFromUpstream(xdg.ConfigHome)
+	return configHome.UntypedJoin("turborepo")
+}