Implement --size-only flag to sync on size not checksum & modtime - fixes #75

README.md

@@ -136,13 +136,14 @@ General options:
 ```
       --bwlimit=0: Bandwidth limit in kBytes/s, or use suffix k|M|G
       --checkers=8: Number of checkers to run in parallel.
-      -c, --checksum=false: Skip based on checksum, not mod-time & size
+      -c, --checksum=false: Skip based on checksum & size, not mod-time & size
       --config="~/.rclone.conf": Config file.
       --contimeout=1m0s: Connect timeout
   -n, --dry-run=false: Do a trial run with no permanent changes
       --log-file="": Log everything to this file
       --modify-window=1ns: Max time diff to be considered the same
   -q, --quiet=false: Print as little stuff as possible
+      --size-only=false: Skip based on size only, not mod-time or checksum
       --stats=1m0s: Interval to print stats (0 to disable)
       --timeout=5m0s: IO idle timeout
       --transfers=4: Number of file transfers to run in parallel.

docs/content/docs.md

@@ -124,6 +124,7 @@ This help.
       --log-file="": Log everything to this file
       --modify-window=1ns: Max time diff to be considered the same
   -q, --quiet=false: Print as little stuff as possible
+      --size-only=false: Skip based on size only, not mod-time or checksum
       --stats=1m0s: Interval to print stats (0 to disable)
       --timeout=5m0s: IO idle timeout
       --transfers=4: Number of file transfers to run in parallel.

docs/content/dropbox.md

@@ -84,3 +84,10 @@ Dropbox datastores are limited to 100,000 rows so this is the maximum
 number of files rclone can manage on Dropbox.
 
 Dropbox is case sensitive which can sometimes cause duplicated files.
+
+If you use the desktop sync tool and rclone on the same files then the
+md5sums and modification times may get out of sync as far as rclone is
+concerned.  This will cause `Corrupted on transfer: md5sums differ`
+error message when fetching files.  You can work around this by using
+the `--size-only` flag to ignore the md5sums and modification times
+for these files.

fs/accounting.go

@@ -124,6 +124,16 @@ func (s *StatsInfo) GetErrors() int64 {
 	return s.errors
 }
 
+// ResetCounters sets the counters (bytes, checks, errors, transfers) to 0
+func (s *StatsInfo) ResetCounters() {
+	s.lock.RLock()
+	defer s.lock.RUnlock()
+	s.bytes = 0
+	s.errors = 0
+	s.checks = 0
+	s.transfers = 0
+}
+
 // Errored returns whether there have been any errors
 func (s *StatsInfo) Errored() bool {
 	s.lock.RLock()

fs/config.go

@@ -44,7 +44,8 @@ var (
 	checkers       = pflag.IntP("checkers", "", 8, "Number of checkers to run in parallel.")
 	transfers      = pflag.IntP("transfers", "", 4, "Number of file transfers to run in parallel.")
 	configFile     = pflag.StringP("config", "", ConfigPath, "Config file.")
-	checkSum       = pflag.BoolP("checksum", "c", false, "Skip based on checksum, not mod-time & size")
+	checkSum       = pflag.BoolP("checksum", "c", false, "Skip based on checksum & size, not mod-time & size")
+	sizeOnly       = pflag.BoolP("size-only", "", false, "Skip based on size only, not mod-time or checksum")
 	dryRun         = pflag.BoolP("dry-run", "n", false, "Do a trial run with no permanent changes")
 	connectTimeout = pflag.DurationP("contimeout", "", 60*time.Second, "Connect timeout")
 	timeout        = pflag.DurationP("timeout", "", 5*60*time.Second, "IO idle timeout")
@@ -121,6 +122,7 @@ type ConfigInfo struct {
 	Quiet          bool
 	DryRun         bool
 	CheckSum       bool
+	SizeOnly       bool
 	ModifyWindow   time.Duration
 	Checkers       int
 	Transfers      int
@@ -197,6 +199,7 @@ func LoadConfig() {
 	Config.Timeout = *timeout
 	Config.ConnectTimeout = *connectTimeout
 	Config.CheckSum = *checkSum
+	Config.SizeOnly = *sizeOnly
 
 	ConfigPath = *configFile
 

fs/operations.go

@@ -54,15 +54,16 @@ func CheckMd5sums(src, dst Object) (bool, error) {
 // size, mtime and MD5SUM
 //
 // If the src and dst size are different then it is considered to be
-// not equal.
+// not equal.  If --size-only is in effect then this is the only check
+// that is done.
 //
 // If the size is the same and the mtime is the same then it is
-// considered to be equal.  This is the heuristic rsync uses when
-// not using --checksum.
+// considered to be equal.  This check is skipped if using --checksum.
 //
-// If the size is the same and and mtime is different or unreadable
-// and the MD5SUM is the same then the file is considered to be equal.
-// In this case the mtime on the dst is updated.
+// If the size is the same and mtime is different, unreadable or
+// --checksum is set and the MD5SUM is the same then the file is
+// considered to be equal.  In this case the mtime on the dst is
+// updated if --checksum is not set.
 //
 // Otherwise the file is considered to be not equal including if there
 // were errors reading info.
@@ -71,6 +72,10 @@ func Equal(src, dst Object) bool {
 		Debug(src, "Sizes differ")
 		return false
 	}
+	if Config.SizeOnly {
+		Debug(src, "Sizes identical")
+		return true
+	}
 
 	var srcModTime time.Time
 	if !Config.CheckSum {

fs/operations_test.go

@@ -175,44 +175,100 @@ func TestCopyRedownload(t *testing.T) {
 func TestSyncBasedOnCheckSum(t *testing.T) {
 	cleanTempDir(t)
 	fs.Config.CheckSum = true
+	defer func() { fs.Config.CheckSum = false }()
 
 	WriteFile("check sum", "", t1)
+	local_items := []fstest.Item{
+		{Path: "check sum", Size: 0, ModTime: t1, Md5sum: "d41d8cd98f00b204e9800998ecf8427e"},
+	}
+	fstest.CheckListingWithPrecision(t, flocal, local_items, fs.Config.ModifyWindow)
 
-	transfers_before := fs.Stats.GetTransfers()
+	fs.Stats.ResetCounters()
 	err := fs.Sync(fremote, flocal, true)
 	if err != nil {
 		t.Fatalf("Initial sync failed: %v", err)
 	}
-	transfers_after := fs.Stats.GetTransfers()
 
-	//We should have transferred exactly one file.
-	if transfers_after-1 != transfers_before {
-		t.Fatalf("Initial sync didn't do what we wanted.")
+	// We should have transferred exactly one file.
+	if fs.Stats.GetTransfers() != 1 {
+		t.Fatalf("Sync 1: want 1 transfer, got %d", fs.Stats.GetTransfers())
 	}
 
+	remote_items := local_items
+	fstest.CheckListingWithPrecision(t, fremote, remote_items, fs.Config.ModifyWindow)
+
 	err = os.Chtimes(localName+"/check sum", t2, t2)
 	if err != nil {
 		t.Fatalf("Chtimes failed: %v", err)
 	}
+	local_items = []fstest.Item{
+		{Path: "check sum", Size: 0, ModTime: t2, Md5sum: "d41d8cd98f00b204e9800998ecf8427e"},
+	}
+	fstest.CheckListingWithPrecision(t, flocal, local_items, fs.Config.ModifyWindow)
 
-	transfers_before = fs.Stats.GetTransfers()
+	fs.Stats.ResetCounters()
 	err = fs.Sync(fremote, flocal, true)
 	if err != nil {
 		t.Fatalf("Sync failed: %v", err)
 	}
-	transfers_after = fs.Stats.GetTransfers()
 
-	//We should have transferred no files
-	if transfers_after != transfers_before {
-		t.Fatalf("We synced, though we shouldn't have.")
+	// We should have transferred no files
+	if fs.Stats.GetTransfers() != 0 {
+		t.Fatalf("Sync 2: want 0 transfers, got %d", fs.Stats.GetTransfers())
 	}
 
-	remote_items := []fstest.Item{
-		{Path: "check sum", Size: 0, ModTime: t1, Md5sum: "d41d8cd98f00b204e9800998ecf8427e"},
-	}
+	fstest.CheckListingWithPrecision(t, flocal, local_items, fs.Config.ModifyWindow)
+	fstest.CheckListingWithPrecision(t, fremote, remote_items, fs.Config.ModifyWindow)
+
+	cleanTempDir(t)
+}
+
+// Create a file and sync it. Change the last modified date and the
+// file contents but not the size.  If we're only doing sync by size
+// only, we expect nothing to to be transferred on the second sync.
+func TestSyncSizeOnly(t *testing.T) {
+	cleanTempDir(t)
+	fs.Config.SizeOnly = true
+	defer func() { fs.Config.SizeOnly = false }()
+
+	WriteFile("sizeonly", "potato", t1)
 	local_items := []fstest.Item{
-		{Path: "check sum", Size: 0, ModTime: t2, Md5sum: "d41d8cd98f00b204e9800998ecf8427e"},
+		{Path: "sizeonly", Size: 6, ModTime: t1, Md5sum: "8ee2027983915ec78acc45027d874316"},
 	}
+	fstest.CheckListingWithPrecision(t, flocal, local_items, fs.Config.ModifyWindow)
+
+	fs.Stats.ResetCounters()
+	err := fs.Sync(fremote, flocal, true)
+	if err != nil {
+		t.Fatalf("Initial sync failed: %v", err)
+	}
+
+	// We should have transferred exactly one file.
+	if fs.Stats.GetTransfers() != 1 {
+		t.Fatalf("Sync 1: want 1 transfer, got %d", fs.Stats.GetTransfers())
+	}
+
+	remote_items := local_items
+	fstest.CheckListingWithPrecision(t, fremote, remote_items, fs.Config.ModifyWindow)
+
+	// Update mtime, md5sum but not length of file
+	WriteFile("sizeonly", "POTATO", t2)
+	local_items = []fstest.Item{
+		{Path: "sizeonly", Size: 6, ModTime: t2, Md5sum: "8ac6f27a282e4938125482607ccfb55f"},
+	}
+	fstest.CheckListingWithPrecision(t, flocal, local_items, fs.Config.ModifyWindow)
+
+	fs.Stats.ResetCounters()
+	err = fs.Sync(fremote, flocal, true)
+	if err != nil {
+		t.Fatalf("Sync failed: %v", err)
+	}
+
+	// We should have transferred no files
+	if fs.Stats.GetTransfers() != 0 {
+		t.Fatalf("Sync 2: want 0 transfers, got %d", fs.Stats.GetTransfers())
+	}
+
 	fstest.CheckListingWithPrecision(t, flocal, local_items, fs.Config.ModifyWindow)
 	fstest.CheckListingWithPrecision(t, fremote, remote_items, fs.Config.ModifyWindow)