locking: new "locks --verify" option

"locks --verify" verifies the server-side lock owner and denotes own
locks in the output by 'O'.

Internally, the /locks/verify API is used to have the server reporting
locks categorized by "ours" and "theirs". Note that this categorization
must be performed on the server because only the server knows the
mapping between login and lock owner name.

This basically resolves issue #3252 but does not yet address the
combination of "--verify" and "--cached".

commands/command_locks.go

@@ -1,7 +1,7 @@
 package commands
 
 import (
-	"encoding/json"
+	"io"
 	"os"
 	"sort"
 	"strings"
@@ -44,11 +44,44 @@ func locksCommand(cmd *cobra.Command, args []string) {
 		}
 	}
 
-	locks, err := lockClient.SearchLocks(filters, locksCmdFlags.Limit, locksCmdFlags.Local, locksCmdFlags.Cached)
+	if locksCmdFlags.Verify {
+		if len(filters) > 0 {
+			Exit("--verify option can't be combined with filters")
+		}
+		if locksCmdFlags.Local {
+			Exit("--verify option can't be combined with --local")
+		}
+		if locksCmdFlags.Cached {
+			Exit("--verify option can't be combined with --cached")
+		}
+	}
+
+	var locks []locking.Lock
+	var locksOwned map[locking.Lock]bool
+	var jsonWriteFunc func(io.Writer) error
+	if locksCmdFlags.Verify {
+		var ourLocks, theirLocks []locking.Lock
+		ourLocks, theirLocks, err = lockClient.SearchLocksVerifiable(locksCmdFlags.Limit)
+		jsonWriteFunc = func(writer io.Writer) error {
+			return lockClient.EncodeLocksVerifiable(ourLocks, theirLocks, writer)
+		}
+
+		locks = append(ourLocks, theirLocks...)
+		locksOwned = make(map[locking.Lock]bool)
+		for _, lock := range ourLocks {
+			locksOwned[lock] = true
+		}
+	} else {
+		locks, err = lockClient.SearchLocks(filters, locksCmdFlags.Limit, locksCmdFlags.Local, locksCmdFlags.Cached)
+		jsonWriteFunc = func(writer io.Writer) error {
+			return lockClient.EncodeLocks(locks, writer)
+		}
+	}
+
 	// Print any we got before exiting
 
 	if locksCmdFlags.JSON {
-		if err := json.NewEncoder(os.Stdout).Encode(locks); err != nil {
+		if err := jsonWriteFunc(os.Stdout); err != nil {
 			Error(err.Error())
 		}
 		return
@@ -77,7 +110,16 @@ func locksCommand(cmd *cobra.Command, args []string) {
 
 		pathPadding := tools.MaxInt(maxPathLen-len(lock.Path), 0)
 		namePadding := tools.MaxInt(maxNameLen-len(ownerName), 0)
-		Print("%s%s\t%s%s\tID:%s", lock.Path, strings.Repeat(" ", pathPadding),
+		kind := ""
+		if locksOwned != nil {
+			if locksOwned[lock] {
+				kind = "O "
+			} else {
+				kind = "  "
+			}
+		}
+
+		Print("%s%s%s\t%s%s\tID:%s", kind, lock.Path, strings.Repeat(" ", pathPadding),
 			ownerName, strings.Repeat(" ", namePadding),
 			lock.Id,
 		)
@@ -108,6 +150,9 @@ type locksFlags struct {
 	// for non-local queries, report cached query results from the last query
 	// instead of actually querying the server again
 	Cached bool
+	// for non-local queries, verify lock owner on server and
+	// denote our locks in output
+	Verify bool
 }
 
 // Filters produces a filter based on locksFlags instance.
@@ -137,6 +182,7 @@ func init() {
 		cmd.Flags().IntVarP(&locksCmdFlags.Limit, "limit", "l", 0, "optional limit for number of results to return")
 		cmd.Flags().BoolVarP(&locksCmdFlags.Local, "local", "", false, "only list cached local record of own locks")
 		cmd.Flags().BoolVarP(&locksCmdFlags.Cached, "cached", "", false, "list cached lock information from the last remote query, instead of actually querying the server")
+		cmd.Flags().BoolVarP(&locksCmdFlags.Verify, "verify", "", false, "verify lock owner on server and mark own locks by 'O'")
 		cmd.Flags().BoolVarP(&locksCmdFlags.JSON, "json", "", false, "print output in json")
 	})
 }

docs/man/git-lfs-locks.1.ronn

@@ -29,6 +29,16 @@ Lists current locks from the Git LFS server.
   last known locks in case you are offline. There is no guarantee that locks
   on the server have not changed in the meanwhile.
 
+* `--verify`:
+  Verifies the lock owner on the server and marks our own locks by 'O'.
+  Own locks are actually held by us and corresponding files can be updated for
+  the next push. All other locks are held by someone else.
+  Contrary to --local, this option will also detect locks which are held by us
+  despite no local lock information being available (e.g. because the file had
+  been locked from a different clone);
+  it will also detect 'broken' locks (e.g. if someone else has forcefully
+  unlocked our files).
+
 * `-l <num>` `--limit=<num>`:
   Specifies number of results to return.
 

locking/locks.go

@@ -3,6 +3,7 @@ package locking
 import (
 	"encoding/json"
 	"fmt"
+	"io"
 	"net/http"
 	"os"
 	"path/filepath"
@@ -468,13 +469,24 @@ func (c *Client) readLocksFromCacheFile(path string) ([]Lock, error) {
 	return locks, nil
 }
 
+func (c *Client) EncodeLocks(locks []Lock, writer io.Writer) error {
+	return json.NewEncoder(writer).Encode(locks)
+}
+
+func (c *Client) EncodeLocksVerifiable(ourLocks, theirLocks []Lock, writer io.Writer) error {
+	return json.NewEncoder(writer).Encode(&lockVerifiableList{
+		Ours:   ourLocks,
+		Theirs: theirLocks,
+	})
+}
+
 func (c *Client) writeLocksToCacheFile(path string, locks []Lock) error {
 	file, err := os.Create(path)
 	if err != nil {
 		return err
 	}
 
-	err = json.NewEncoder(file).Encode(locks)
+	err = c.EncodeLocks(locks, file)
 	if err != nil {
 		file.Close()
 		return err