[Sync] Implementation of model association for passwords using sync API

chrome/browser/password_manager/password_syncable_service.cc

 // Copyright 2013 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "chrome/browser/password_manager/password_syncable_service.h"
 
 #include "base/location.h"
+#include "base/memory/scoped_vector.h"

[Ilya Sherman, 2013/12/05 07:01:54]

nit: Redundant with the header's include.

+#include "base/metrics/histogram.h"

[Ilya Sherman, 2013/12/05 07:01:54]

nit: unused.

+#include "base/stl_util.h"

[Ilya Sherman, 2013/12/05 07:01:54]

nit: unused?

 #include "base/strings/utf_string_conversions.h"
 #include "chrome/browser/password_manager/password_store.h"
 #include "components/autofill/core/common/password_form.h"
 #include "net/base/escape.h"
 #include "sync/api/sync_error_factory.h"
 
+bool PasswordSyncableService::MergeLocalAndSyncPasswords(
+    const sync_pb::PasswordSpecificsData& password_specifics,
+    const autofill::PasswordForm& password_form,
+    autofill::PasswordForm* new_password_form) {
+  if (password_specifics.scheme() == password_form.scheme &&
+      password_form.signon_realm == password_specifics.signon_realm() &&
+      password_form.origin.spec() == password_specifics.origin() &&
+      password_form.action.spec() == password_specifics.action() &&
+      UTF16ToUTF8(password_form.username_element) ==
+          password_specifics.username_element() &&
+      UTF16ToUTF8(password_form.password_element) ==
+          password_specifics.password_element() &&
+      UTF16ToUTF8(password_form.username_value) ==
+          password_specifics.username_value() &&
+      UTF16ToUTF8(password_form.password_value) ==
+          password_specifics.password_value() &&
+      password_specifics.ssl_valid() == password_form.ssl_valid &&
+      password_specifics.preferred() == password_form.preferred &&
+      password_specifics.date_created() ==
+          password_form.date_created.ToInternalValue() &&
+      password_specifics.blacklisted() ==
+          password_form.blacklisted_by_user) {
+    return false;
+  }
+
+  // If the passwords differ, take the one that was created more recently.
+  if (base::Time::FromInternalValue(password_specifics.date_created()) <=
+          password_form.date_created) {
+    *new_password_form = password_form;
+  } else {
+    PasswordSyncableService::ExtractPasswordFromSpecifics(
+        password_specifics,
+        new_password_form);
+  }
+
+  return true;
+}

[Ilya Sherman, 2013/12/05 07:01:54]

nit: Please arrange the code in the implementation file to match the order in
the header file.

+
 PasswordSyncableService::PasswordSyncableService(
     scoped_refptr<PasswordStore> password_store)
     : password_store_(password_store) {
 }
 
 PasswordSyncableService::~PasswordSyncableService() {}
 
+void PasswordSyncableService::CreateOrUpdateEntry(
+    const syncer::SyncData& data,
+    PasswordEntryMap* umatched_data_from_password_db,
+    ScopedVector<autofill::PasswordForm>* new_entries,
+    ScopedVector<autofill::PasswordForm>* updated_entries,
+    syncer::SyncChangeList* updated_db_entries) {
+  const sync_pb::EntitySpecifics& specifics = data.GetSpecifics();
+  const sync_pb::PasswordSpecificsData& password_specifics(
+      specifics.password().client_only_encrypted_data());
+  std::string tag = MakeTag(password_specifics);
+
+  // Check whether the data from sync is already in password store.

[Ilya Sherman, 2013/12/05 07:01:54]

nit: "in password store" -> "in the password store"

+  PasswordEntryMap::iterator umatched_data_from_password_db_iter =

[Ilya Sherman, 2013/12/05 07:01:54]

nit: Perhaps name this something more like "existing_local_entry" or
"existing_entry_from_password_db"?

+      umatched_data_from_password_db->find(tag);
+  if (umatched_data_from_password_db_iter ==
+      umatched_data_from_password_db->end()) {

[Ilya Sherman, 2013/12/05 07:01:54]

nit: Please indent this line four more spaces.

+    // The sync data is not in the password store, so we need to create it in
+    // the password store. Add the entry to the new_entries list.
+    scoped_ptr<autofill::PasswordForm> new_password(
+        new autofill::PasswordForm());
+    ExtractPasswordFromSpecifics(password_specifics, new_password.get());
+    new_entries->push_back(new_password.release());
+  } else {
+    // The entry is in password store. If the entries are not identical, then
+    // the entries need to be merged.
+    scoped_ptr<autofill::PasswordForm> new_password(
+        new autofill::PasswordForm());
+    if (MergeLocalAndSyncPasswords(password_specifics,
+            *(umatched_data_from_password_db_iter->second),
+            new_password.get())) {
+      // It is possible that both the sync database and the passwords
+      // database need to be updated to reflect the merged data. Rather
+      // than checking we simply update both.

[Ilya Sherman, 2013/12/05 07:01:54]

Is it actually possible that both need to be updated?  If so, how?  Looking at
the code, it looks like one is always newer.

If I'm understanding the code correctly, perhaps a more accurate comment would
be something like: "Rather than checking which database -- sync or local --
needs updating, simply push an update to both.  This will end up being a no-op
for the database that didn't need an update."

+      updated_db_entries->push_back(
+          syncer::SyncChange(FROM_HERE,
+                             syncer::SyncChange::ACTION_UPDATE,
+                             CreateSyncData(*(new_password.get()))));
+
+      updated_entries->push_back(new_password.release());
+    }
+    // Remove the entry from the entry map to indicate a match has been found.
+    // Entries that remain in the map at the end of associating all sync entries
+    // will be treated as additions that need to be propagated to sync.
+    umatched_data_from_password_db->erase(umatched_data_from_password_db_iter);
+  }
+}
+
 syncer::SyncMergeResult
 PasswordSyncableService::MergeDataAndStartSyncing(
     syncer::ModelType type,
     const syncer::SyncDataList& initial_sync_data,
     scoped_ptr<syncer::SyncChangeProcessor> sync_processor,
     scoped_ptr<syncer::SyncErrorFactory> sync_error_factory) {
   syncer::SyncMergeResult merge_result(type);
   sync_error_factory_ = sync_error_factory.Pass();
   sync_processor_ = sync_processor.Pass();
 
-  merge_result.set_error(sync_error_factory->CreateAndUploadError(
-      FROM_HERE,
-      "Password Syncable Service Not Implemented."));
+  ScopedVector<autofill::PasswordForm> password_entries;
+  if (!password_store_->FillAutofillableLogins(&(password_entries.get()))) {
+    // Password store often fails to load passwords. Track failures with UMA.
+    // (http://crbug.com/249000)
+    syncer::SyncError::LogDataLoadFailure(syncer::PASSWORDS);
+    merge_result.set_error(sync_error_factory->CreateAndUploadError(
+        FROM_HERE,
+        "Failed to get passwords from store."));
+    return merge_result;
+  }
+
+  PasswordEntryMap new_local_entries;
+  for (PasswordForms::iterator it = password_entries.begin();
+       it != password_entries.end();
+       ++it) {
+     autofill::PasswordForm* password_form = *it;
+     // We add all the db entries as |new_local_entries| initially. During
+     // model association entries that match a sync entry will be
+     // removed and this list will only contain entries that are not in sync.
+     new_local_entries[MakeTag(*password_form)] = password_form;
+  }
+
+  merge_result.set_num_items_before_association(new_local_entries.size());
+
+  // List that contains the entries that are known only to sync.
+  ScopedVector<autofill::PasswordForm> new_sync_entries;
+
+  // List that contains the entries that are known to both sync and db but
+  // have updates in sync. They need to be updated in the passwords db.
+  ScopedVector<autofill::PasswordForm> updated_sync_entries;
+
+  // Changes from password db that needs to be propagated to sync.

[Ilya Sherman, 2013/12/05 07:01:54]

nit: "needs" -> "need"

+  syncer::SyncChangeList db_changes;
+  for (syncer::SyncDataList::const_iterator sync_iter =
+           initial_sync_data.begin();
+       sync_iter != initial_sync_data.end(); ++sync_iter) {
+    CreateOrUpdateEntry(*sync_iter,
+                        &new_local_entries,
+                        &new_sync_entries,
+                        &updated_sync_entries,
+                        &db_changes);
+  }
+
+  WriteToPasswordStore(new_sync_entries.get(),
+                       updated_sync_entries.get());
+
+  merge_result.set_num_items_after_association(
+      merge_result.num_items_before_association() + new_sync_entries.size());
+
+  merge_result.set_num_items_added(new_sync_entries.size());
+
+  merge_result.set_num_items_modified(updated_sync_entries.size());
+
+  for (PasswordEntryMap::iterator it = new_local_entries.begin();
+       it != new_local_entries.end();
+       ++it) {
+    db_changes.push_back(syncer::SyncChange(FROM_HERE,
+                              syncer::SyncChange::ACTION_ADD,
+                              CreateSyncData(*(it->second))));

[Ilya Sherman, 2013/12/05 07:01:54]

nit: Please align all three arguments to syncer::SyncChange().

+  }
+
+  merge_result.set_error(
+      sync_processor_->ProcessSyncChanges(FROM_HERE, db_changes));
   return merge_result;
 }
 
 void PasswordSyncableService::StopSyncing(syncer::ModelType type) {
 }
 
 syncer::SyncDataList PasswordSyncableService::GetAllSyncData(
     syncer::ModelType type) const {
   syncer::SyncDataList sync_data;
   return sync_data;
 }
 
 syncer::SyncError PasswordSyncableService::ProcessSyncChanges(
     const tracked_objects::Location& from_here,
     const syncer::SyncChangeList& change_list) {
   syncer::SyncError error(FROM_HERE,
                           syncer::SyncError::UNRECOVERABLE_ERROR,
                           "Password Syncable Service Not Implemented.",
                           syncer::PASSWORDS);
   return error;
 }
 
 void PasswordSyncableService::WriteToPasswordStore(
-    PasswordForms* new_entries,
-    PasswordForms* updated_entries) {
+    const PasswordForms& new_entries,
+    const PasswordForms& updated_entries) {
   for (std::vector<autofill::PasswordForm*>::const_iterator it =
-           new_entries->begin();
-       it != new_entries->end();
+           new_entries.begin();
+       it != new_entries.end();
        ++it) {
     password_store_->AddLoginImpl(**it);
   }
 
   for (std::vector<autofill::PasswordForm*>::const_iterator it =
-           updated_entries->begin();
-       it != updated_entries->end();
+           updated_entries.begin();
+       it != updated_entries.end();
        ++it) {
     password_store_->UpdateLoginImpl(**it);
   }
 
-  if (!new_entries->empty() || !updated_entries->empty()) {
+  if (!new_entries.empty() || !updated_entries.empty()) {
     // We have to notify password store observers of the change by hand since
     // we use internal password store interfaces to make changes synchronously.
-    password_store_->PostNotifyLoginsChanged();
+    NotifyPasswordStoreOfLoginChanges();
   }
 }
 
+void PasswordSyncableService::NotifyPasswordStoreOfLoginChanges() {
+  password_store_->PostNotifyLoginsChanged();
+}
+
 syncer::SyncData PasswordSyncableService::CreateSyncData(
     const autofill::PasswordForm& password_form) {
   sync_pb::EntitySpecifics password_data;
   sync_pb::PasswordSpecificsData* password_specifics =
       password_data.mutable_password()->mutable_client_only_encrypted_data();
   password_specifics->set_scheme(password_form.scheme);
   password_specifics->set_signon_realm(password_form.signon_realm);
   password_specifics->set_origin(password_form.origin.spec());
   password_specifics->set_action(password_form.action.spec());
   password_specifics->set_username_element(
@@ skipping 41 matching lines @@
 // static
 std::string PasswordSyncableService::MakeTag(
     const sync_pb::PasswordSpecificsData& password) {
   return MakeTag(password.origin(),
                  password.username_element(),
                  password.username_value(),
                  password.password_element(),
                  password.signon_realm());
 }
 
+// static
+void PasswordSyncableService::ExtractPasswordFromSpecifics(
+     const sync_pb::PasswordSpecificsData& password,
+     autofill::PasswordForm* new_password) {
+  new_password->scheme =
+      static_cast<autofill::PasswordForm::Scheme>(password.scheme());
+  new_password->signon_realm = password.signon_realm();
+  new_password->origin = GURL(password.origin());
+  new_password->action = GURL(password.action());
+  new_password->username_element =
+      UTF8ToUTF16(password.username_element());
+  new_password->password_element =
+      UTF8ToUTF16(password.password_element());
+  new_password->username_value =
+      UTF8ToUTF16(password.username_value());
+  new_password->password_value =
+      UTF8ToUTF16(password.password_value());
+  new_password->ssl_valid = password.ssl_valid();
+  new_password->preferred = password.preferred();
+  new_password->date_created =
+      base::Time::FromInternalValue(password.date_created());
+  new_password->blacklisted_by_user =
+      password.blacklisted();
+}