PasswordStore: Clean up expectations about rewriting vectors of forms

chrome/browser/password_manager/password_store_mac.cc

 // Copyright (c) 2012 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_store_mac.h"
 #include "chrome/browser/password_manager/password_store_mac_internal.h"
 
 #include <CoreServices/CoreServices.h>
 #include <set>
 #include <string>
@@ skipping 1044 matching lines @@
   }
   return changes;
 }
 
 ScopedVector<autofill::PasswordForm> PasswordStoreMac::FillMatchingLogins(
     const autofill::PasswordForm& form,
     AuthorizationPromptPolicy prompt_policy) {
   chrome::ScopedSecKeychainSetUserInteractionAllowed user_interaction_allowed(
       prompt_policy == ALLOW_PROMPT);
 
-  if (!login_metadata_db_)
+  ScopedVector<PasswordForm> database_forms;
+  if (!login_metadata_db_ ||
+      !login_metadata_db_->GetLogins(form, &database_forms)) {
     return ScopedVector<autofill::PasswordForm>();
-
-  ScopedVector<PasswordForm> database_forms;
-  login_metadata_db_->GetLogins(form, &database_forms);
+  }
 
   // Let's gather all signon realms we want to match with keychain entries.
   std::set<std::string> realm_set;
   realm_set.insert(form.signon_realm);
   for (const autofill::PasswordForm* db_form : database_forms) {
     // TODO(vabr): We should not be getting different schemes here.
     // http://crbug.com/340112
     if (form.scheme != db_form->scheme)
       continue;  // Forms with different schemes never match.
     const std::string& original_singon_realm(db_form->original_signon_realm);
@@ skipping 38 matching lines @@
 void PasswordStoreMac::GetAutofillableLoginsImpl(
     scoped_ptr<PasswordStore::GetLoginsRequest> request) {
   ScopedVector<autofill::PasswordForm> obtained_forms;
   FillAutofillableLogins(&obtained_forms);
   request->NotifyConsumerWithResults(obtained_forms.Pass());
 }
 
 bool PasswordStoreMac::FillAutofillableLogins(
     ScopedVector<autofill::PasswordForm>* forms) {
   DCHECK(thread_->message_loop() == base::MessageLoop::current());
+  forms->clear();
 
   ScopedVector<PasswordForm> database_forms;
   if (!login_metadata_db_ ||
       !login_metadata_db_->GetAutofillableLogins(&database_forms))
     return false;
 
   internal_keychain_helpers::GetPasswordsForForms(*keychain_, &database_forms,
                                                   forms);
 
   if (!database_forms.empty()) {
     RemoveDatabaseForms(&database_forms);
     NotifyLoginsChanged(FormsToRemoveChangeList(database_forms.get()));
   }
 
   return true;
 }
 
 bool PasswordStoreMac::FillBlacklistLogins(
     ScopedVector<autofill::PasswordForm>* forms) {
+  forms->clear();

[engedy, 2015/03/09 13:33:18]

nit: Sorry, I was meaning to say after the DCHECK. This looks weird. :)

[vabr (Chromium), 2015/03/09 17:44:15]

Done.
I agree that preconditions-checking DCHECK should be the first line, I should
have looked more carefully.

   DCHECK(thread_->message_loop() == base::MessageLoop::current());
   return login_metadata_db_ && login_metadata_db_->GetBlacklistLogins(forms);
 }
 
 bool PasswordStoreMac::AddToKeychainIfNecessary(const PasswordForm& form) {
   if (form.blacklisted_by_user) {
     return true;
   }
   MacKeychainPasswordFormAdapter keychainAdapter(keychain_.get());
   return keychainAdapter.AddPassword(form);
 }
 
 bool PasswordStoreMac::DatabaseHasFormMatchingKeychainForm(
     const autofill::PasswordForm& form) {
   DCHECK(login_metadata_db_);
   bool has_match = false;
   ScopedVector<autofill::PasswordForm> database_forms;
-  login_metadata_db_->GetLogins(form, &database_forms);
+  if (!login_metadata_db_->GetLogins(form, &database_forms))
+    return false;
   for (const autofill::PasswordForm* db_form : database_forms) {
     // Below we filter out forms with non-empty original_signon_realm, because
     // those signal fuzzy matches, and we are only interested in exact ones.
     if (db_form->original_signon_realm.empty() &&
         internal_keychain_helpers::FormsMatchForMerge(
             form, *db_form, internal_keychain_helpers::STRICT_FORM_MATCH) &&
         db_form->origin == form.origin) {
       has_match = true;
       break;
     }
@@ skipping 22 matching lines @@
     owned_keychain_adapter.RemovePassword(**i);
   }
 }
 
 void PasswordStoreMac::CleanOrphanedForms(
     ScopedVector<autofill::PasswordForm>* orphaned_forms) {
   DCHECK(orphaned_forms);
   DCHECK(login_metadata_db_);
 
   ScopedVector<autofill::PasswordForm> database_forms;
-  login_metadata_db_->GetAutofillableLogins(&database_forms);
+  if (!login_metadata_db_->GetAutofillableLogins(&database_forms))
+    return;
 
   // Filter forms with corresponding Keychain entry out of |database_forms|.
   ScopedVector<PasswordForm> forms_with_keychain_entry;
   internal_keychain_helpers::GetPasswordsForForms(*keychain_, &database_forms,
                                                   &forms_with_keychain_entry);
 
   // Clean up any orphaned database entries.
   RemoveDatabaseForms(&database_forms);
 
   // Move the orphaned DB forms to the output parameter.
   AppendSecondToFirst(orphaned_forms, &database_forms);
 }