[Sync] Add nigori node conflict resolution.

chrome/browser/sync/engine/conflict_resolver.cc

Index: chrome/browser/sync/engine/conflict_resolver.cc
diff --git a/chrome/browser/sync/engine/conflict_resolver.cc b/chrome/browser/sync/engine/conflict_resolver.cc
index e06d02d06ed4b4f153838f88c8f2d512ad29c884..91c3d46e3e3a40a657f96c9478de0a551cba4741 100644
--- a/chrome/browser/sync/engine/conflict_resolver.cc
+++ b/chrome/browser/sync/engine/conflict_resolver.cc
@@ -12,10 +12,12 @@
 #include "base/metrics/histogram.h"
 #include "chrome/browser/sync/engine/syncer.h"
 #include "chrome/browser/sync/engine/syncer_util.h"
+#include "chrome/browser/sync/protocol/nigori_specifics.pb.h"
 #include "chrome/browser/sync/protocol/service_constants.h"
 #include "chrome/browser/sync/sessions/status_controller.h"
 #include "chrome/browser/sync/syncable/directory_manager.h"
 #include "chrome/browser/sync/syncable/syncable.h"
+#include "chrome/browser/sync/util/cryptographer.h"
 
 using std::map;
 using std::set;
@@ -43,6 +45,7 @@ enum SimpleConflictResolutions {
   UNDELETE,                  // Resolved by undeleting local item.
   IGNORE_ENCRYPTION,         // Resolved by ignoring an encryption-only server
                              // change. TODO(zea): implement and use this.
+  NIGORI_MERGE,              // Resolved by merging nigori nodes.
   CONFLICT_RESOLUTION_SIZE,
 };
 
@@ -78,6 +81,7 @@ void ConflictResolver::OverwriteServerChanges(WriteTransaction* trans,
 ConflictResolver::ProcessSimpleConflictResult
 ConflictResolver::ProcessSimpleConflict(WriteTransaction* trans,
                                         const Id& id,
+                                        const Cryptographer* cryptographer,
                                         StatusController* status) {
   MutableEntry entry(trans, syncable::GET_BY_ID, id);
   // Must be good as the entry won't have been cleaned up.
@@ -124,7 +128,40 @@ ConflictResolver::ProcessSimpleConflict(WriteTransaction* trans,
                                     entry.Get(syncable::SERVER_PARENT_ID);
     bool entry_deleted = entry.Get(syncable::IS_DEL);
 
-    if (!entry_deleted && name_matches && parent_matches) {
+    // We manually merge nigori data.
+    // TODO(zea): Find a better way of doing this. As it stands, we have to

[tim (not reviewing), 2011/12/20 17:54:05]

Maybe move this comment down to the set_sync_tabs bit?

[Nicolas Zea, 2011/12/20 19:54:10]

Done.

+    // update this code whenever we add a new non-cryptographer related field to
+    // the nigori node.
+    if (entry.GetModelType() == syncable::NIGORI) {
+      // Create a new set of specifics based on the server specifics (which
+      // preserves their encryption keys).
+      sync_pb::EntitySpecifics specifics =
+          entry.Get(syncable::SERVER_SPECIFICS);
+      sync_pb::NigoriSpecifics* nigori =
+          specifics.MutableExtension(sync_pb::nigori);
+      // Store the merged set of encrypted types (cryptographer->Update(..) will
+      // have merged the local types already).
+      cryptographer->UpdateNigoriFromEncryptedTypes(nigori);
+      // The local set of keys is already merged with the server's set within
+      // the cryptographer. If we don't have pending keys we can store the
+      // merged set back immediately. Else we preserve the server keys and will
+      // update the nigori when the user provides the pending passphrase via
+      // SetPassphrase(..).
+      if (cryptographer->is_ready()) {
+        cryptographer->GetKeys(nigori->mutable_encrypted());
+      }
+      if (entry.Get(syncable::SPECIFICS).GetExtension(sync_pb::nigori)
+              .sync_tabs()) {
+        nigori->set_sync_tabs(true);
+      }
+      entry.Put(syncable::SPECIFICS, specifics);
+      DVLOG(1) << "Resovling simple conflict, merging nigori nodes: " << entry;
+      status->increment_num_server_overwrites();
+      OverwriteServerChanges(trans, &entry);
+      UMA_HISTOGRAM_ENUMERATION("Sync.ResolveSimpleConflict",
+                                NIGORI_MERGE,
+                                CONFLICT_RESOLUTION_SIZE);
+    } else if (!entry_deleted && name_matches && parent_matches) {
       // TODO(zea): We may prefer to choose the local changes over the server
       // if we know the local changes happened before (or vice versa).
       // See http://crbug.com/76596
@@ -460,6 +497,7 @@ bool ConflictResolver::ResolveSimpleConflicts(
     const ConflictProgress& progress,
     sessions::StatusController* status) {
   WriteTransaction trans(FROM_HERE, syncable::SYNCER, dir);
+  Cryptographer* cryptographer = dir.manager()->GetCryptographer(&trans);

[tim (not reviewing), 2011/12/20 17:54:05]

Is manager() or the cryptographer really not available any other way?

[Nicolas Zea, 2011/12/20 19:54:10]

Neither the status controller nor the conflict progress have access to the
manager/cryptographer. Another option would be to plumb in the manager as an
additional parameter from the ResolveConflicts command and ResolveConflict
method, in addition to the ScopedDirLookup, but this seemed simpler, since the
ScopedDirLookup wraps around the manager already.

   bool forward_progress = false;
   // First iterate over simple conflict items (those that belong to no set).
   set<Id>::const_iterator conflicting_item_it;
@@ -472,7 +510,7 @@ bool ConflictResolver::ResolveSimpleConflicts(
     if (item_set_it == progress.IdToConflictSetEnd() ||
         0 == item_set_it->second) {
       // We have a simple conflict.
-      switch (ProcessSimpleConflict(&trans, id, status)) {
+      switch (ProcessSimpleConflict(&trans, id, cryptographer, status)) {
         case NO_SYNC_PROGRESS:
           {
             int conflict_count = (simple_conflict_count_map_[id] += 2);