Merge branch 'naive-conflict-resolve'

README.md

@@ -73,7 +73,6 @@ $ cd ~/gdrive
 ### Pulling
 
 The `pull` command downloads data from Google Drive that does not exist locally, and deletes local data that is not present on Google Drive. 
-
 Run it without any arguments to pull all of the files from the current path:
 
 ```shell
@@ -86,6 +85,21 @@ To force download from paths that otherwise would be marked with no-changes
 $ drive pull -force
 ```
 
++ Note:
+  In relation to [#57](https://github.com/odeke-em/drive/issues/57) and [@rakyll's #49](https://github.com/rakyll/drive/issues/49).
+   A couple of scenarios in which data was getting totally clobbered and unrecoverable, drive now tries to play it safe and warn you if your data could potentially be lost e.g during a to-disk clobber for which you have no backup. At least with a push you have the luxury of untrashing content. To disable this safety, run drive with flag `-force` e.g:
+
+```shell
+$ drive pull -force collaboration_documents
+```
+
+Playing the safety card even more, if you want to get changes that are non clobberable ie only additions
+run drive with flag `-no-clobber` e.g:
+
+```shell
+$ drive pull -no-clobber Makefile
+```
+
 To pull specific files or directories, pass in one or more paths:
 
 ```shell
@@ -98,6 +112,7 @@ Note: To ignore checksum verification during a pull:
 $ drive pull -ignore-checksum
 ```
 
+
 #### Exporting Docs
 
 By default, the `pull` command will export Google Docs documents as PDF files. To specify other formats, use the `-export` option:
@@ -139,6 +154,18 @@ Note: To ignore checksum verification during a push:
 $ drive push -ignore-checksum
 ```
 
+For safety with non clobberable changes i.e only additions:
+
+```shell
+$ drive push -no-clobber
+```
+
++ Due to the reasons explained in the pull section, drive should be able to warn you in case of total clobbers on data. To turn off this behaviour/safety, pass in the `-force` flag i.e:
+
+```shell
+$ drive push -force sure_of_content
+```
+
 
 To get Google Drive to convert a file to its native Google Docs format
 

src/changes.go

@@ -96,7 +96,6 @@ func (g *Commands) changeListResolve(relToRoot, fsPath string, isPush bool) (cl
 		l = NewLocalFile(fsPath, localinfo)
 	}
 
-	fmt.Println("Resolving...")
 	return g.resolveChangeListRecv(isPush, relToRoot, relToRoot, r, l)
 }
 
@@ -276,17 +275,32 @@ func reduceToSize(changes []*Change, isPush bool) (totalSize int64) {
 	return totalSize
 }
 
-func summarizeChanges(changes []*Change, reduce bool) {
+func checkAndPrintChanges(changes []*Change, reduce bool) bool {
+	// Firstly detect the conflicting changes and if present return false
+	var conflicts []string
 	for _, c := range changes {
-		if c.Op() != OpNone {
-			fmt.Println(c.Symbol(), c.Path)
+		if c.Op() == OpModConflict {
+			conflicts = append(conflicts, c.Path)
 		}
 	}
+
+	conflictCount := len(conflicts)
+	if conflictCount >= 1 {
+		fmt.Printf("These %d file(s) would be overwritten. Use -%s to override this behaviour\n", conflictCount, ForceKey)
+		for _, path := range conflicts {
+			fmt.Println(path)
+		}
+		return false
+	}
+
 	if reduce {
 		opMap := map[int]sizeCounter{}
 
 		for _, c := range changes {
 			op := c.Op()
+			if op != OpNone {
+				fmt.Println(c.Symbol(), c.Path)
+			}
 			counter := opMap[op]
 			counter.count += 1
 			if c.Src != nil {
@@ -306,6 +320,7 @@ func summarizeChanges(changes []*Change, reduce bool) {
 			fmt.Printf("%s %s\n", name, counter.String())
 		}
 	}
+	return true
 }
 
 func promptForChanges() bool {
@@ -320,7 +335,9 @@ func printChangeList(changes []*Change, noPrompt bool, noClobber bool) bool {
 		fmt.Println("Everything is up-to-date.")
 		return false
 	}
-	summarizeChanges(changes, !noPrompt)
+	if !checkAndPrintChanges(changes, !noPrompt) {
+		return false
+	}
 
 	if noPrompt {
 		return true

src/help.go

@@ -39,6 +39,8 @@ const (
 	UntrashKey    = "untrash"
 	UnpubKey      = "unpub"
 	VersionKey    = "version"
+
+	ForceKey = "force"
 )
 
 const (

src/pull.go

@@ -34,6 +34,8 @@ const (
 // It doesn't check if there are remote changes if isForce is set.
 func (g *Commands) Pull() (err error) {
 	var cl []*Change
+
+	fmt.Println("Resolving...")
 	for _, relToRootPath := range g.opts.Sources {
 		fsPath := g.context.AbsPathOf(relToRootPath)
 		ccl, cErr := g.changeListResolve(relToRootPath, fsPath, false)

src/push.go

@@ -36,6 +36,7 @@ func (g *Commands) Push() (err error) {
 	root := g.context.AbsPathOf("")
 	var cl []*Change
 
+	fmt.Println("Resolving...")
 	c := make(chan os.Signal, 1)
 	signal.Notify(c, os.Interrupt, os.Kill)
 

src/stat.go

@@ -104,6 +104,7 @@ func prettyFileStat(relToRootPath string, file *File) {
 		&keyValue{"Size", prettyBytes(file.Size)},
 		&keyValue{"DirType", dirType},
 		&keyValue{"MimeType", file.MimeType},
+		&keyValue{"Etag", file.Etag},
 		&keyValue{"ModTime", fmt.Sprintf("%v", file.ModTime)},
 	}
 	if !file.IsDir {

src/types.go

@@ -29,6 +29,7 @@ const (
 	OpAdd
 	OpDelete
 	OpMod
+	OpModConflict
 )
 
 const (
@@ -47,10 +48,11 @@ const (
 var BigFileSize = int64(1024 * 1024 * 400)
 
 var opPrecedence = map[int]int{
-	OpNone:   0,
-	OpDelete: 1,
-	OpAdd:    2,
-	OpMod:    3,
+	OpNone:        0,
+	OpDelete:      1,
+	OpAdd:         2,
+	OpMod:         3,
+	OpModConflict: 4,
 }
 
 type File struct {
@@ -121,6 +123,7 @@ type Change struct {
 	Src            *File
 	Force          bool
 	NoClobber      bool
+	IgnoreConflict bool
 	IgnoreChecksum bool
 }
 
@@ -158,6 +161,8 @@ func opToString(op int) (string, string) {
 		return "\033[31m-\033[0m", "Deletion"
 	case OpMod:
 		return "\033[33mM\033[0m", "Modification"
+	case OpModConflict:
+		return "\033[35mX\033[0m", "Clashing modification"
 	default:
 		return "", ""
 	}
@@ -238,16 +243,14 @@ func fileDifferences(src, dest *File, ignoreChecksum bool) int {
 	}
 
 	if !ignoreChecksum {
-		// Only compute the checksum if the size is the same.
+		// Only compute the checksum if the size differs
 		if sizeDiffers(difference) || md5Checksum(src) != md5Checksum(dest) {
 			difference |= DifferMd5Checksum
 		}
 	}
 	return difference
 }
 
-// If the preliminary sameFile test passes,
-// then perform an Md5 checksum comparison
 func sameFileTillChecksum(src, dest *File, ignoreChecksum bool) bool {
 	return fileDifferences(src, dest, ignoreChecksum) == DifferNone
 }
@@ -265,18 +268,33 @@ func (c *Change) op() int {
 	if c.Src.IsDir != c.Dest.IsDir {
 		return OpMod
 	}
+	if c.Src.IsDir {
+		return OpNone
+	}
+
+	mask := fileDifferences(c.Src, c.Dest, c.IgnoreChecksum)
 
-	if !c.Src.IsDir && !sameFileTillChecksum(c.Src, c.Dest, c.IgnoreChecksum) {
+	if sizeDiffers(mask) || checksumDiffers(mask) {
+		if c.IgnoreConflict {
+			return OpMod
+		}
+		return OpModConflict
+	}
+	if modTimeDiffers(mask) {
 		return OpMod
 	}
+
 	return OpNone
 }
 
 func (c *Change) Op() int {
+	op := c.op()
 	if c.Force {
+		if op == OpModConflict {
+			return OpMod
+		}
 		return OpAdd
 	}
-	op := c.op()
 	if op != OpAdd && c.NoClobber {
 		return OpNone
 	}