Merge pull request #2 from vbatts/findbase

base: much needed love

base/base.go

@@ -14,22 +14,24 @@ import (
 	"github.com/vbatts/dedupe-linker/file"
 )
 
+// NewBase populates the directories needed in a dedupe-base directory
 func NewBase(path string, hashName string) (*Base, error) {
-	root := filepath.Join(path, "dedup")
 	for _, p := range []string{"blobs/" + hashName, "state", "tmp"} {
-		if err := os.MkdirAll(filepath.Join(root, p), 0755); err != nil && !os.IsExist(err) {
+		if err := os.MkdirAll(filepath.Join(path, p), 0755); err != nil && !os.IsExist(err) {
 			return nil, err
 		}
 	}
-	return &Base{Path: root, HashName: hashName, Hash: cryptomap.DetermineHash(hashName)}, nil
+	return &Base{Path: path, HashName: hashName, Hash: cryptomap.DetermineHash(hashName)}, nil
 }
 
+// Base is the destination for all hardlinks. Where stored objects are in a content addressible tree.
 type Base struct {
 	Path     string
 	HashName string
 	Hash     crypto.Hash
 }
 
+// Stat provides the os.FileInfo for the object of `sum` address
 func (b Base) Stat(sum string) (os.FileInfo, error) {
 	return os.Stat(b.blobPath(sum))
 }
@@ -41,12 +43,15 @@ func (b Base) blobPath(sum string) string {
 	return filepath.Join(b.Path, "blobs", b.HashName, sum[0:2], sum)
 }
 
-type ReaderSeekerCloser interface {
+// ReadSeekCloser is like an io.ReadCloser, but can Seek too
+type ReadSeekCloser interface {
 	io.Reader
 	io.Seeker
 	io.Closer
 }
 
+// SameFile checks whether the object of `sum` address, and `path` file path are the same file.
+// This checks by inode and device.
 func (b Base) SameFile(sum, path string) bool {
 	var (
 		bInode, dInode uint64
@@ -66,7 +71,7 @@ func (b Base) SameFile(sum, path string) bool {
 }
 
 // GetBlob store the content from src, for the sum and hashType
-func (b Base) GetBlob(sum string) (ReaderSeekerCloser, error) {
+func (b Base) GetBlob(sum string) (ReadSeekCloser, error) {
 	return os.Open(b.blobPath(sum))
 }
 
@@ -118,7 +123,8 @@ func (b Base) tmpFile() (*os.File, error) {
 	return ioutil.TempFile(filepath.Join(b.Path, "tmp"), "put")
 }
 
-// Hard link the file from src to the blob for sum
+// LinkFrom make a hard link the file from src to the blob of address `sum`.
+// TODO this function is going away, because it makes no assessment of the checksum of `src`
 func (b Base) LinkFrom(src, sum string) error {
 	if err := os.MkdirAll(filepath.Dir(b.blobPath(sum)), 0756); err != nil && !os.IsExist(err) {
 		return err
@@ -135,7 +141,8 @@ func randomString() (string, error) {
 	return fmt.Sprintf("%x", buf), nil
 }
 
-// SafeLink overrides newname if it already exists. If there is an error in creating the link, the transaction is rolled back
+// SafeLink overrides newname if it already exists. If there is an error in
+// creating the link, the transaction is rolled back
 func SafeLink(oldname, newname string) error {
 	var backupName string
 	// check if newname exists
@@ -169,7 +176,7 @@ func SafeLink(oldname, newname string) error {
 	return nil
 }
 
-// Hard link the file for sum to the path at dest
+// LinkTo makes a hard link the file of address `sum` to the path at `dest`
 func (b Base) LinkTo(dest, sum string) error {
 	if err := os.MkdirAll(filepath.Dir(dest), 0755); err != nil && !os.IsExist(err) {
 		return err

base/base_test.go

@@ -2,7 +2,6 @@ package base
 
 import (
 	"bytes"
-	"fmt"
 	"io/ioutil"
 	"os"
 	"path"
@@ -50,7 +49,7 @@ func TestGetPut(t *testing.T) {
 		t.Fatal(err)
 	}
 
-	rHash := "deadbeaf"
+	rHash := "8f074e76e82ae6156c451019840a6f857bbe5157"
 	rMsg := "this is the dead beef"
 
 	r := bytes.NewReader([]byte(rMsg))
@@ -58,12 +57,18 @@ func TestGetPut(t *testing.T) {
 	if err != nil {
 		t.Error(err)
 	}
+	if sum != rHash {
+		t.Errorf("expected %q; got %q", rHash, sum)
+	}
 
 	fi, err := b.Stat(rHash)
 	if err != nil {
 		t.Error(err)
 	}
-	fmt.Printf("%#v\n", fi.Sys())
+	if fi == nil {
+		t.Fatal("did not find the blob " + rHash)
+	}
+	//fmt.Printf("%#v\n", fi.Sys())
 
 	if err = b.LinkTo(path.Join(srcDir, "beef1.txt"), rHash); err != nil {
 		t.Error(err)
@@ -72,7 +77,10 @@ func TestGetPut(t *testing.T) {
 	if err != nil {
 		t.Error(err)
 	}
-	fmt.Printf("%#v\n", fi2.Sys())
+	if fi2 == nil {
+		t.Fatal("did not find the linked file " + path.Join(srcDir, "beef1.txt"))
+	}
+	//fmt.Printf("%#v\n", fi2.Sys())
 
 	if err = b.LinkTo(path.Join(srcDir, "beef1.txt"), rHash); err != nil && !os.IsExist(err) {
 		t.Error(err)

base/findbase.go

@@ -0,0 +1,61 @@
+package base
+
+import (
+	"io/ioutil"
+	"os"
+	"path/filepath"
+	"syscall"
+
+	"github.com/vbatts/dedupe-linker/file"
+)
+
+// FindBase steps up the directory tree to find the top-level that is still on
+// the same device as the path provided
+func FindBase(path string) (string, error) {
+	stat, err := os.Lstat(path)
+	if err != nil {
+		return "", err
+	}
+	if stat.IsDir() {
+		return findBaseInfo(stat)
+	}
+
+	return FindBase(filepath.Dir(path))
+}
+
+func findBaseInfo(stat os.FileInfo) (string, error) {
+	dirstat, err := os.Lstat(filepath.Dir(stat.Name()))
+	if err != nil {
+		return "", err
+	}
+	if stat.Name() == dirstat.Name() {
+		return stat.Name(), nil
+	}
+
+	if sameDevice(stat, dirstat) {
+		return findBaseInfo(dirstat)
+	}
+	return stat.Name(), nil
+}
+
+func hasPermission(path string) bool {
+	stat, err := os.Lstat(path)
+	if err != nil {
+		return false
+	}
+	if !stat.IsDir() {
+		path = filepath.Dir(path)
+	}
+	fh, err := ioutil.TempFile(path, "perm.test.")
+	if err != nil {
+		return false
+	}
+	os.Remove(fh.Name())
+	return true
+}
+
+func sameDevice(file1, file2 os.FileInfo) bool {
+	sys1 := file1.Sys().(*syscall.Stat_t)
+	sys2 := file2.Sys().(*syscall.Stat_t)
+	return ((file.MajorDev(sys1.Dev) == file.MajorDev(sys2.Dev)) && (file.MinorDev(sys1.Dev) == file.MinorDev(sys2.Dev)))
+}

base/findbase_test.go

@@ -0,0 +1,76 @@
+package base
+
+import (
+	"io/ioutil"
+	"os"
+	"testing"
+)
+
+func TestHasPermission(t *testing.T) {
+	if !hasPermission("/tmp") {
+		t.Error("expected to have permission to /tmp, but did not")
+	}
+
+	if hasPermission("/") {
+		t.Error("expected to not have permission to /, but did")
+	}
+}
+
+func TestSameDev(t *testing.T) {
+	file1, err := ioutil.TempFile("", "test")
+	if err != nil {
+		t.Fatal(err)
+	}
+	defer file1.Close()
+	file2, err := ioutil.TempFile("", "test")
+	if err != nil {
+		t.Fatal(err)
+	}
+	defer file2.Close()
+
+	stat1, err := file1.Stat()
+	if err != nil {
+		t.Fatal(err)
+	}
+	stat2, err := file2.Stat()
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	if !sameDevice(stat1, stat2) {
+		t.Errorf("expected the two files to be on same device. But %q and %q are not", file1.Name(), file2.Name())
+	} else {
+		os.Remove(stat1.Name())
+		os.Remove(stat2.Name())
+	}
+}
+
+// perhaps this is naive. Travis' /tmp is on the same device and not sure how to request it be tmpfs w/o needing sudo
+func testNotSameDev(t *testing.T) {
+	file1, err := ioutil.TempFile("/tmp", "test")
+	if err != nil {
+		t.Fatal(err)
+	}
+	defer file1.Close()
+	file2, err := ioutil.TempFile(os.Getenv("HOME"), "test")
+	if err != nil {
+		t.Fatal(err)
+	}
+	defer file2.Close()
+
+	stat1, err := file1.Stat()
+	if err != nil {
+		t.Fatal(err)
+	}
+	stat2, err := file2.Stat()
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	if sameDevice(stat1, stat2) {
+		t.Errorf("expected the two files _not_ to be on same device. But %q and %q are not", file1.Name(), file2.Name())
+	} else {
+		os.Remove(stat1.Name())
+		os.Remove(stat2.Name())
+	}
+}

cryptomap/crypto.go

@@ -2,36 +2,37 @@ package cryptomap
 
 import (
 	"crypto"
+	"log"
+	"strings"
+
+	// Importing all the currently supported hashes
 	_ "crypto/md5"
 	_ "crypto/sha1"
 	_ "crypto/sha256"
 	_ "crypto/sha512"
-	"log"
-	"strings"
 )
 
-var knownCiphers = map[string]crypto.Hash{
-	"md5": crypto.MD5,
+// DefaultCipher is the crypto cipher default used if none is specified or
+// specified is unknown.
+var DefaultCipher = "sha1"
+
+// Ciphers is the known set of mappings for string to crypto.Hash
+// use an init() to add custom hash ciphers
+var Ciphers = map[string]crypto.Hash{
+	"md5":    crypto.MD5,
+	"sha1":   crypto.SHA1,
+	"sha224": crypto.SHA224,
+	"sha256": crypto.SHA256,
+	"sha384": crypto.SHA384,
+	"sha512": crypto.SHA512,
 }
 
+// DetermineHash takes a generic string, like "sha1" and returns the
+// corresponding crypto.Hash
 func DetermineHash(str string) (h crypto.Hash) {
-	switch strings.ToLower(str) {
-	case "md5":
-		h = crypto.MD5
-	case "sha1":
-		h = crypto.SHA1
-	case "sha224":
-		h = crypto.SHA224
-	case "sha256":
-		h = crypto.SHA256
-	case "sha384":
-		h = crypto.SHA384
-	case "sha512":
-		h = crypto.SHA512
-	default:
-		log.Printf("WARNING: unknown cipher %q. using 'sha1'", str)
-		h = crypto.SHA1
+	if h, ok := Ciphers[strings.ToLower(str)]; ok {
+		return h
 	}
-
-	return h
+	log.Printf("WARNING: unknown cipher %q. using %q", str, DefaultCipher)
+	return Ciphers[DefaultCipher]
 }

file/dev.go

@@ -0,0 +1,94 @@
+package file
+
+import (
+	"fmt"
+	"os"
+	"syscall"
+)
+
+// SameInodePaths checks whether path1 and path2 are the same inode
+func SameInodePaths(path1, path2 string) (match bool, err error) {
+	var inode1, inode2 uint64
+	if inode1, err = GetInode(path1); err != nil {
+		return false, err
+	}
+	if inode2, err = GetInode(path2); err != nil {
+		return false, err
+	}
+	return inode1 == inode2, nil
+}
+
+// SameDevPaths checks whether path1 and path2 are on the same device
+func SameDevPaths(path1, path2 string) (match bool, err error) {
+	var dev1, dev2 uint64
+	if dev1, err = GetDev(path1); err != nil {
+		return false, err
+	}
+	if dev2, err = GetDev(path2); err != nil {
+		return false, err
+	}
+	return dev1 == dev2, nil
+}
+
+// FormatDev has a scary name, but just pretty prints the stat_t.dev as "major:minor"
+func FormatDev(stat *syscall.Stat_t) string {
+	return fmt.Sprintf("%d:%d", MajorDev(stat.Dev), MinorDev(stat.Dev))
+}
+
+// MajorDev provides the major device number from a stat_t.dev
+func MajorDev(dev uint64) uint64 {
+	return (((dev >> 8) & 0xfff) | ((dev >> 32) & ^uint64(0xfff)))
+}
+
+// MinorDev provides the minor device number from a stat_t.dev
+func MinorDev(dev uint64) uint64 {
+	return ((dev & 0xff) | ((dev >> 12) & ^uint64(0xff)))
+}
+
+// GetLstat returns the system stat_t for the file at path.
+// (symlinks are not deferenced)
+func GetLstat(path string) (*syscall.Stat_t, error) {
+	fi, err := os.Lstat(path)
+	if err != nil {
+		return nil, err
+	}
+	return fi.Sys().(*syscall.Stat_t), nil
+}
+
+// GetStat returns the system stat_t for the file at path.
+// (symlinks are deferenced)
+func GetStat(path string) (*syscall.Stat_t, error) {
+	fi, err := os.Stat(path)
+	if err != nil {
+		return nil, err
+	}
+	return fi.Sys().(*syscall.Stat_t), nil
+}
+
+// GetInode returns the inode for path
+func GetInode(path string) (uint64, error) {
+	stat, err := GetStat(path)
+	if err != nil {
+		return 0, err
+	}
+	return stat.Ino, nil
+}
+
+// GetDev returns the device for path
+func GetDev(path string) (uint64, error) {
+	stat, err := GetStat(path)
+	if err != nil {
+		return 0, err
+	}
+	return stat.Dev, nil
+}
+
+// GetNlink returns the number of links for path. For directories, that is
+// number of entries. For regular files, that is number of hardlinks.
+func GetNlink(path string) (uint64, error) {
+	stat, err := GetStat(path)
+	if err != nil {
+		return 0, err
+	}
+	return stat.Nlink, nil
+}

file/hash.go

@@ -6,11 +6,13 @@ import (
 	"io"
 	"os"
 	"path/filepath"
-	"syscall"
 	"time"
 )
 
-type FileHashInfo struct {
+// HashInfo for tracking the information regarding a file, it's checksum
+// and status.
+// If Err is set then the caller must take an appropriate action.
+type HashInfo struct {
 	HashType crypto.Hash
 	Hash     string
 	Path     string
@@ -19,8 +21,10 @@ type FileHashInfo struct {
 	Err      error
 }
 
-func HashFileGetter(path string, hash crypto.Hash, workers int, done <-chan struct{}) <-chan FileHashInfo {
-	out := make(chan FileHashInfo, workers)
+// HashFileGetter walks the provided `path` with `workers` number of threads.
+// The channel of HashInfo are for each regular file encountered.
+func HashFileGetter(path string, hash crypto.Hash, workers int, done <-chan struct{}) <-chan HashInfo {
+	out := make(chan HashInfo, workers)
 	go func() {
 		err := filepath.Walk(path, func(path string, info os.FileInfo, err error) error {
 			if err != nil {
@@ -39,15 +43,15 @@ func HashFileGetter(path string, hash crypto.Hash, workers int, done <-chan stru
 			}
 		})
 		if err != nil {
-			out <- FileHashInfo{Err: err}
+			out <- HashInfo{Err: err}
 		}
 		close(out)
 	}()
 	return out
 }
 
-func hashFile(path string, hash crypto.Hash, info os.FileInfo) *FileHashInfo {
-	fhi := FileHashInfo{HashType: hash, Path: path, ModTime: info.ModTime(), Size: info.Size()}
+func hashFile(path string, hash crypto.Hash, info os.FileInfo) *HashInfo {
+	fhi := HashInfo{HashType: hash, Path: path, ModTime: info.ModTime(), Size: info.Size()}
 	h := hash.New()
 	fh, err := os.Open(path)
 	if err != nil {
@@ -63,74 +67,3 @@ func hashFile(path string, hash crypto.Hash, info os.FileInfo) *FileHashInfo {
 	fhi.Hash = fmt.Sprintf("%x", h.Sum(nil))
 	return &fhi
 }
-
-// SameInodePaths checks whether path1 and path2 are the same inode
-func SameInodePaths(path1, path2 string) (match bool, err error) {
-	var inode1, inode2 uint64
-	if inode1, err = GetInode(path1); err != nil {
-		return false, err
-	}
-	if inode2, err = GetInode(path2); err != nil {
-		return false, err
-	}
-	return inode1 == inode2, nil
-}
-
-// SameInodePaths checks whether path1 and path2 are on the same device
-func SameDevPaths(path1, path2 string) (match bool, err error) {
-	var dev1, dev2 uint64
-	if dev1, err = GetDev(path1); err != nil {
-		return false, err
-	}
-	if dev2, err = GetDev(path2); err != nil {
-		return false, err
-	}
-	return dev1 == dev2, nil
-}
-
-func FormatDev(stat *syscall.Stat_t) string {
-	return fmt.Sprintf("%d:%d", MajorDev(stat.Dev), MinorDev(stat.Dev))
-}
-
-func MajorDev(dev uint64) uint64 {
-	return (((dev >> 8) & 0xfff) | ((dev >> 32) & ^uint64(0xfff)))
-}
-
-func MinorDev(dev uint64) uint64 {
-	return ((dev & 0xff) | ((dev >> 12) & ^uint64(0xff)))
-}
-
-func GetStat(path string) (*syscall.Stat_t, error) {
-	fi, err := os.Stat(path)
-	if err != nil {
-		return nil, err
-	}
-	return fi.Sys().(*syscall.Stat_t), nil
-}
-
-// GetInode returns the inode for path
-func GetInode(path string) (uint64, error) {
-	stat, err := GetStat(path)
-	if err != nil {
-		return 0, err
-	}
-	return stat.Ino, nil
-}
-
-// GetDev returns the device for path
-func GetDev(path string) (uint64, error) {
-	stat, err := GetStat(path)
-	if err != nil {
-		return 0, err
-	}
-	return stat.Dev, nil
-}
-
-// GetNlink returns the number of links for path
-func GetNlink(path string) (uint64, error) {
-	stat, err := GetStat(path)
-	if err != nil {
-		return 0, err
-	}
-	return stat.Nlink, nil
-}

main.go

@@ -14,10 +14,10 @@ import (
 )
 
 var (
-	varBaseDir = filepath.Join(os.Getenv("HOME"), ".local/dedupe-linker/var")
+	varBaseDir = filepath.Join(os.Getenv("HOME"), ".dedupe-linker/")
 
 	flVarBase = flag.String("b", varBaseDir, "base directory where files are duplicated")
-	flCipher  = flag.String("c", "sha1", "block cipher to use (sha1, or sha256)")
+	flCipher  = flag.String("c", cryptomap.DefaultCipher, "block cipher to use (sha1, or sha256)")
 	flWorkers = flag.Int("w", 2, "workers to do summing")
 	flNoop    = flag.Bool("noop", false, "don't do any moving or linking")
 	flDebug   = flag.Bool("debug", false, "enable debug output")
@@ -53,8 +53,8 @@ func main() {
 
 	var (
 		hash = cryptomap.DetermineHash(*flCipher)
-		//infos = []*file.FileHashInfo{}
-		//results := make(chan file.FileHashInfo, 2)
+		//infos = []*file.HashInfo{}
+		//results := make(chan file.HashInfo, 2)
 	)
 
 	for _, arg := range flag.Args() {
@@ -77,7 +77,7 @@ func main() {
 				fmt.Printf("%s  [%d]  %s\n", fi.Hash, fi.Size, fi.Path)
 			} else {
 				if os.Getenv("DEBUG") != "" {
-					fmt.Printf("%q: %q\n", fi.Path, ourbase.HasBlob(fi.Hash))
+					fmt.Printf("%q: %t\n", fi.Path, ourbase.HasBlob(fi.Hash))
 				}
 				if ourbase.HasBlob(fi.Hash) && !ourbase.SameFile(fi.Hash, fi.Path) {
 					if err := ourbase.LinkTo(fi.Path, fi.Hash); err != nil {

walker/walker.go

@@ -1,14 +1,15 @@
+// Package walker is a work-in-progress
 package walker
 
 import (
 	"github.com/vbatts/dedupe-linker/base"
 )
 
-type Walker struct {
+type walker struct {
 	Base *base.Base
 }
 
-func (w Walker) Walk(path string, quit chan int) error {
+func (w walker) Walk(path string, quit chan int) error {
 	// XXX what is going on here?
 	select {
 	case <-quit: