Started working on the main library (nearly complete)

2023-12-24 08:05:56 -06:00
parent b2a3920c1f
commit 5de59627df
10 changed files with 550 additions and 16 deletions
@@ -0,0 +1,241 @@
+package squashfs
+
+import (
+	"io"
+	"io/fs"
+	"path"
+	"path/filepath"
+	"slices"
+	"strings"
+
+	"github.com/CalebQ42/squashfs/squashfs"
+	"github.com/CalebQ42/squashfs/squashfs/directory"
+)
+
+// FS is a fs.FS representation of a squashfs directory.
+// Implements fs.GlobFS, fs.ReadDirFS, fs.ReadFileFS, fs.StatFS, and fs.SubFS
+type FS struct {
+	d      *squashfs.Directory
+	r      *Reader
+	parent *FS
+}
+
+// Glob returns the name of the files at the given pattern.
+// All paths are relative to the FS.
+// Uses filepath.Match to compare names.
+func (f *FS) Glob(pattern string) (out []string, err error) {
+	pattern = filepath.Clean(pattern)
+	if !fs.ValidPath(pattern) {
+		return nil, &fs.PathError{
+			Op:   "glob",
+			Path: pattern,
+			Err:  fs.ErrInvalid,
+		}
+	}
+	split := strings.Split(pattern, "/")
+	for i := 0; i < len(f.d.Entries); i++ {
+		if match, _ := path.Match(split[0], f.d.Entries[i].Name); match {
+			if len(split) == 1 {
+				out = append(out, f.d.Entries[i].Name)
+				continue
+			}
+			sub, err := f.Sub(split[0])
+			if err != nil {
+				if pathErr, ok := err.(*fs.PathError); ok {
+					if pathErr.Err == fs.ErrNotExist {
+						continue
+					}
+					pathErr.Op = "glob"
+					pathErr.Path = pattern
+					return nil, pathErr
+				}
+				return nil, &fs.PathError{
+					Op:   "glob",
+					Path: pattern,
+					Err:  err,
+				}
+			}
+			subGlob, err := sub.(fs.GlobFS).Glob(strings.Join(split[1:], "/"))
+			if err != nil {
+				if pathErr, ok := err.(*fs.PathError); ok {
+					if pathErr.Err == fs.ErrNotExist {
+						continue
+					}
+					pathErr.Op = "glob"
+					pathErr.Path = pattern
+					return nil, pathErr
+				}
+				return nil, &fs.PathError{
+					Op:   "glob",
+					Path: pattern,
+					Err:  err,
+				}
+			}
+			for i := 0; i < len(subGlob); i++ {
+				subGlob[i] = f.d.Name + "/" + subGlob[i]
+			}
+			out = append(out, subGlob...)
+		}
+	}
+	return
+}
+
+// Opens the file at name. Returns a *File as an fs.File.
+func (f *FS) Open(name string) (fs.File, error) {
+	name = filepath.Clean(name)
+	if !fs.ValidPath(name) {
+		return nil, &fs.PathError{
+			Op:   "open",
+			Path: name,
+			Err:  fs.ErrInvalid,
+		}
+	}
+	if name == "." || name == "" {
+		return &File{
+			b:      &f.d.Base,
+			r:      f.r,
+			parent: f.parent,
+		}, nil
+	}
+	split := strings.Split(name, "/")
+	i, found := slices.BinarySearchFunc(f.d.Entries, split[0], func(e directory.Entry, name string) int {
+		return strings.Compare(e.Name, name)
+	})
+	if !found {
+		return nil, &fs.PathError{
+			Op:   "open",
+			Path: name,
+			Err:  fs.ErrNotExist,
+		}
+	}
+	b, err := f.r.r.BaseFromEntry(f.d.Entries[i])
+	if err != nil {
+		return nil, err
+	}
+	if len(split) == 1 {
+		return &File{
+			b:      b,
+			r:      f.r,
+			parent: f.parent,
+		}, nil
+	}
+	if !b.IsDir() {
+		return nil, &fs.PathError{
+			Op:   "open",
+			Path: name,
+			Err:  fs.ErrNotExist,
+		}
+	}
+	d, err := b.ToDir(f.r.r)
+	if err != nil {
+		return nil, err
+	}
+	return (&FS{
+		d:      d,
+		r:      f.r,
+		parent: f,
+	}).Open(strings.Join(split[1:], "/"))
+}
+
+// Returns all DirEntry's for the directory at name.
+// If name is not a directory, returns an error.
+func (f *FS) ReadDir(name string) ([]fs.DirEntry, error) {
+	name = filepath.Clean(name)
+	if !fs.ValidPath(name) {
+		return nil, &fs.PathError{
+			Op:   "readdir",
+			Path: name,
+			Err:  fs.ErrInvalid,
+		}
+	}
+	if name == "." || name == "" {
+		return (&File{
+			b:      &f.d.Base,
+			parent: f.parent,
+			r:      f.r,
+		}).ReadDir(-1)
+	}
+	fil, err := f.Open(name)
+	if err != nil {
+		return nil, err
+	}
+	return fil.(*File).ReadDir(-1)
+}
+
+// Returns the contents of the file at name.
+func (f *FS) ReadFile(name string) (out []byte, err error) {
+	name = filepath.Clean(name)
+	if !fs.ValidPath(name) {
+		return nil, &fs.PathError{
+			Op:   "readfile",
+			Path: name,
+			Err:  fs.ErrInvalid,
+		}
+	}
+	if name == "." || name == "" {
+		return nil, fs.ErrInvalid
+	}
+	fil, err := f.Open(name)
+	if err != nil {
+		return nil, err
+	}
+	if !fil.(*File).IsRegular() {
+		return nil, fs.ErrInvalid
+	}
+	return io.ReadAll(fil)
+}
+
+// Returns the fs.FileInfo for the file at name.
+func (f *FS) Stat(name string) (fs.FileInfo, error) {
+	name = filepath.Clean(name)
+	if !fs.ValidPath(name) {
+		return nil, &fs.PathError{
+			Op:   "stat",
+			Path: name,
+			Err:  fs.ErrInvalid,
+		}
+	}
+	if name == "." || name == "" {
+		return (&File{
+			b:      &f.d.Base,
+			parent: f.parent,
+			r:      f.r,
+		}).Stat()
+	}
+	fil, err := f.Open(name)
+	if err != nil {
+		return nil, err
+	}
+	return fil.(*File).Stat()
+}
+
+// Returns the FS at dir
+func (f *FS) Sub(dir string) (fs.FS, error) {
+	dir = filepath.Clean(dir)
+	if !fs.ValidPath(dir) {
+		return nil, &fs.PathError{
+			Op:   "dir",
+			Path: dir,
+			Err:  fs.ErrInvalid,
+		}
+	}
+	if dir == "." || dir == "" {
+		return f, nil
+	}
+	fil, err := f.Open(dir)
+	if err != nil {
+		return nil, err
+	}
+	if !fil.(*File).IsDir() {
+		return nil, &fs.PathError{
+			Op:   "dir",
+			Path: dir,
+			Err:  fs.ErrInvalid,
+		}
+	}
+	return fil.(*File).FS()
+}
+
+func (f *FS) path() string {
+	return filepath.Join(f.parent.path(), f.d.Name)
+}