components/keyed_service/ios/browser_state_helper.cc

   1 // Copyright 2014 The Chromium Authors. All rights reserved.
   2 // Use of this source code is governed by a BSD-style license that can be
   3 // found in the LICENSE file.
   4
   5 #include "components/keyed_service/ios/browser_state_helper.h"
   6
   7 #include "base/logging.h"
   8 #include "base/supports_user_data.h"
   9 #include "ios/web/public/browser_state.h"
  10
  11 // iOS code is still using BrowserContextKeyedServiceFactory and until the
  12 // upstreaming is complete (http://crbug.com/419366) there is need to have
  13 // mixed dependency between BCKSF and BSKSF.
  14 //
  15 // The implementation has BrowserStateKeyedServiceFactory supporting a
  16 // BrowserContextDependencyManager as DependencyManager. Thus the context
  17 // parameter passed to the BrowserStateKeyedServiceFactory can either be
  18 // content::BrowserContext if the method is invoked by DependencyManager
  19 // or web::BrowserState if the method is invoked via the type-safe public
  20 // API.
  21 //
  22 // The public API of BrowserStateKeyedServiceFactory is type-safe (all
  23 // public method receive web::BrowserState for context object), so only
  24 // methods that take a base::SupportsUserData need to discriminate
  25 // between the two objects.
  26 //
  27 // If the base::SupportsUserData is a web::BrowserState then the public
  28 // method web::BrowserState::FromSupportsUserData can do the conversion
  29 // safely. If this method fails then context is content::BrowserContext
  30 // and the methods defined below allow the embedder to provides helper
  31 // to find the associated web::BrowserState (there is a 1:1 mapping).
  32
  33 namespace {
  34 BrowserStateFromContextFn g_browser_state_from_context = nullptr;
  35 }  // namespace
  36
  37 void SetBrowserStateFromContextHelper(BrowserStateFromContextFn helper) {
  38   g_browser_state_from_context = helper;
  39 }
  40
  41 web::BrowserState* BrowserStateFromContext(base::SupportsUserData* context) {
  42   web::BrowserState* state = nullptr;
  43   if (context) {
  44     state = web::BrowserState::FromSupportsUserData(context);
  45     if (!state && g_browser_state_from_context)
  46       state = g_browser_state_from_context(context);
  47     DCHECK(state) << "cannot convert context to web::BrowserState";
  48   }
  49   return state;
  50 }