[Autofill/Autocomplete Feature] Substring matching instead of prefix matching.

components/password_manager/core/browser/password_autofill_manager.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 "components/password_manager/core/browser/password_autofill_manager.h"
 
 #include <vector>
 
 #include "base/logging.h"
 #include "base/strings/string16.h"
 #include "base/strings/string_util.h"
 #include "base/strings/utf_string_conversions.h"
 #include "components/autofill/core/browser/autofill_driver.h"
 #include "components/autofill/core/browser/popup_item_ids.h"
 #include "components/autofill/core/browser/suggestion.h"
 #include "components/autofill/core/common/autofill_constants.h"
 #include "components/autofill/core/common/autofill_data_validation.h"
+#include "components/autofill/core/common/autofill_util.h"
 #include "components/password_manager/core/browser/affiliation_utils.h"
 #include "components/password_manager/core/browser/password_manager_driver.h"
 #include "components/strings/grit/components_strings.h"
 #include "grit/components_strings.h"
 #include "ui/base/l10n/l10n_util.h"
 
 namespace password_manager {
 
 namespace {
 
@@ skipping 22 matching lines @@
 base::string16 GetHumanReadableRealm(const std::string& signon_realm) {
   // For Android application realms, remove the hash component. Otherwise, make
   // no changes.
   FacetURI maybe_facet_uri(FacetURI::FromPotentiallyInvalidSpec(signon_realm));
   if (maybe_facet_uri.IsValidAndroidFacetURI())
     return base::UTF8ToUTF16("android://" +
                              maybe_facet_uri.android_package_name() + "/");
   return base::UTF8ToUTF16(signon_realm);
 }
 
+// Use this to check if a given suggestion matches the current contents of a
+// field.
+bool DoesSuggestionMatchContents(const base::string16& field_suggestion,
+                                 const base::string16& field_contents) {
+  return autofill::IsContentsPrefixOfSuggestionToken(field_suggestion,
+                                                     field_contents, false) ||
+         StartsWith(field_suggestion, field_contents, false);

[vabr (Chromium), 2015/04/01 11:33:00]

StartsWith is much simpler (and therefore faster) than
IsContentsPrefixOfSuggestionToken. It is reasonable to expect that the contents
will match the prefix of a suggestion often. So swapping the order of the
disjunction to
StartsWith(...) || IsContentsPrefixOfSuggestionToken(...)
looks like a performance win. What do you think?

[Pritam Nikam, 2015/04/01 12:59:37]

Done.

Yeah, point taken!

+}
+
+// If |field_suggestion| matches |field_content|, creates a Suggestion out of it
+// and appends to |suggestions|.
+void AppendSuggestionIfMatching(
+    const base::string16& field_suggestion,
+    const base::string16& field_contents,
+    const std::string& signon_realm,
+    bool show_all,
+    std::vector<autofill::Suggestion>* suggestions) {
+  if (show_all ||
+      DoesSuggestionMatchContents(field_suggestion, field_contents)) {
+    autofill::Suggestion suggestion(ReplaceEmptyUsername(field_suggestion));
+    suggestion.label = GetHumanReadableRealm(signon_realm);
+    suggestion.frontend_id = autofill::POPUP_ITEM_ID_PASSWORD_ENTRY;
+    suggestions->push_back(suggestion);
+  }
+}
+
 // This function attempts to fill |suggestions| and |realms| form |fill_data|
 // based on |current_username|. Unless |show_all| is true, it only picks
-// suggestions where the username has |current_username| as a prefix.
+// suggestions where the username matches |current_username|.
 void GetSuggestions(const autofill::PasswordFormFillData& fill_data,
                     const base::string16& current_username,
                     std::vector<autofill::Suggestion>* suggestions,
                     bool show_all) {
-  if (show_all ||
-      StartsWith(fill_data.username_field.value, current_username, false)) {
-    autofill::Suggestion suggestion(
-        ReplaceEmptyUsername(fill_data.username_field.value));
-    suggestion.label = GetHumanReadableRealm(fill_data.preferred_realm);
-    suggestion.frontend_id = autofill::POPUP_ITEM_ID_PASSWORD_ENTRY;
-    suggestions->push_back(suggestion);
-  }
+  AppendSuggestionIfMatching(fill_data.username_field.value, current_username,
+                             fill_data.preferred_realm, show_all, suggestions);
 
   for (const auto& login : fill_data.additional_logins) {
-    if (show_all || StartsWith(login.first, current_username, false)) {
-      autofill::Suggestion suggestion(ReplaceEmptyUsername(login.first));
-      suggestion.label = GetHumanReadableRealm(login.second.realm);
-      suggestion.frontend_id = autofill::POPUP_ITEM_ID_PASSWORD_ENTRY;
-      suggestions->push_back(suggestion);
-    }
+    AppendSuggestionIfMatching(login.first, current_username,
+                               login.second.realm, show_all, suggestions);
   }
 
   for (const auto& usernames : fill_data.other_possible_usernames) {
     for (size_t i = 0; i < usernames.second.size(); ++i) {
-      if (show_all ||
-          StartsWith(usernames.second[i], current_username, false)) {
-        autofill::Suggestion suggestion(
-            ReplaceEmptyUsername(usernames.second[i]));
-        suggestion.label = GetHumanReadableRealm(usernames.first.realm);
-        suggestion.frontend_id = autofill::POPUP_ITEM_ID_PASSWORD_ENTRY;
-        suggestions->push_back(suggestion);
-      }
+      AppendSuggestionIfMatching(usernames.second[i], current_username,
+                                 usernames.first.realm, show_all, suggestions);
     }
   }
 }
 
 }  // namespace
 
 ////////////////////////////////////////////////////////////////////////////////
 // PasswordAutofillManager, public:
 
 PasswordAutofillManager::PasswordAutofillManager(
@@ skipping 171 matching lines @@
     autofill::PasswordFormFillData* found_password) {
   LoginToPasswordInfoMap::iterator iter = login_to_password_info_.find(key);
   if (iter == login_to_password_info_.end())
     return false;
 
   *found_password = iter->second;
   return true;
 }
 
 }  //  namespace password_manager