[Payments] Code Refactoring for the Subkey Request

components/payments/core/subkey_requester.cc

+// Copyright 2017 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/payments/core/subkey_requester.h"
+
+#include <memory>
+#include <utility>
+
+#include "base/bind.h"
+#include "base/bind_helpers.h"
+#include "base/cancelable_callback.h"
+#include "base/memory/ptr_util.h"
+#include "base/strings/utf_string_conversions.h"
+#include "base/threading/sequenced_task_runner_handle.h"
+#include "base/time/time.h"
+#include "third_party/libaddressinput/chromium/chrome_address_validator.h"
+#include "third_party/libaddressinput/src/cpp/include/libaddressinput/address_data.h"
+#include "third_party/libaddressinput/src/cpp/include/libaddressinput/source.h"
+#include "third_party/libaddressinput/src/cpp/include/libaddressinput/storage.h"
+namespace payments {
+
+namespace {
+
+using ::i18n::addressinput::Source;
+using ::i18n::addressinput::Storage;
+
+class SubKeyRequest : public SubKeyRequester::Request {
+ public:
+  // The |delegate| and |address_validator| need to outlive this Request.
+  SubKeyRequest(const std::string& region_code,
+                int timeout_seconds,
+                SubKeyRequester::Delegate* delegate,
+                autofill::AddressValidator* address_validator)
+      : region_code_(region_code),
+        delegate_(delegate),
+        address_validator_(address_validator),
+        has_responded_(false),
+        on_timeout_(base::Bind(&::payments::SubKeyRequest::OnRulesLoaded,
+                               base::Unretained(this))) {
+    base::SequencedTaskRunnerHandle::Get()->PostDelayedTask(
+        FROM_HERE, on_timeout_.callback(),
+        base::TimeDelta::FromSeconds(timeout_seconds));
+  }
+
+  ~SubKeyRequest() override {}
+
+  void OnRulesLoaded() override {
+    on_timeout_.Cancel();
+    // Check if the timeout happened before the rules were loaded.
+    if (has_responded_)
+      return;

[David Trainor- moved to gerrit, 2017/05/19 17:44:35]

Will this leak the delegate?  This is why we should probably just use a
base::Bind callback IMO.

[Parastoo, 2017/05/23 18:10:38]

Acknowledged.

+    has_responded_ = true;
+
+    delegate_->OnSubKeysReceived(
+        address_validator_->GetRegionSubKeys(region_code_));
+  }
+
+ private:
+  std::string region_code_;
+  // Not owned. Never null. Outlive this object.
+  SubKeyRequester::Delegate* delegate_;
+  autofill::AddressValidator* address_validator_;
+
+  bool has_responded_;
+  base::CancelableCallback<void()> on_timeout_;
+
+  DISALLOW_COPY_AND_ASSIGN(SubKeyRequest);
+};
+
+}  // namespace
+
+SubKeyRequester::SubKeyRequester(std::unique_ptr<Source> source,
+                                 std::unique_ptr<Storage> storage)
+    : address_validator_(std::move(source), std::move(storage), this) {}
+
+SubKeyRequester::~SubKeyRequester() {}
+
+void SubKeyRequester::StartRegionSubKeysRequest(const std::string& region_code,
+                                                int timeout_seconds,
+                                                Delegate* requester) {
+  DCHECK(timeout_seconds >= 0);
+  DCHECK(requester != nullptr);
+
+  std::unique_ptr<SubKeyRequest> request(base::MakeUnique<SubKeyRequest>(

[David Trainor- moved to gerrit, 2017/05/19 17:44:35]

Could just store a base::Callback or base::CallbackOnce here as well since the
interface is basically just a single method.  I don't feel as strongly about
this one though!

[Parastoo, 2017/05/23 18:09:52]

Done.

+      region_code, timeout_seconds, requester, &address_validator_));
+
+  if (AreRulesLoadedForRegion(region_code)) {
+    request->OnRulesLoaded();
+  } else {
+    // Setup the variables so that the subkeys request is sent, when the rules
+    // are loaded.
+    pending_subkey_region_code_ = region_code;
+    pending_subkey_request_ = std::move(request);
+
+    // Start loading the rules for that region. If the rules were already in the
+    // process of being loaded, this call will do nothing.
+    LoadRulesForRegion(region_code);
+  }
+}
+
+bool SubKeyRequester::AreRulesLoadedForRegion(const std::string& region_code) {
+  return address_validator_.AreRulesLoadedForRegion(region_code);
+}
+
+void SubKeyRequester::LoadRulesForRegion(const std::string& region_code) {
+  address_validator_.LoadRules(region_code);
+}
+
+void SubKeyRequester::OnAddressValidationRulesLoaded(
+    const std::string& region_code,
+    bool success) {
+  // The case for |success| == false is already handled. if |success| == false,
+  // AddressValidator::GetRegionSubKeys will return an empty list of subkeys.
+  // Therefore, here, we can ignore the value of |success|.
+
+  // Check if there is any subkey request for that region code.
+  if (!pending_subkey_region_code_.compare(region_code))
+    pending_subkey_request_->OnRulesLoaded();

[David Trainor- moved to gerrit, 2017/05/19 17:44:35]

Are we guaranteed to get a callback for this?  Just want to make sure we won't
have a case where we never notify the callback.

[Parastoo, 2017/05/23 18:09:52]

Yes.

+  pending_subkey_region_code_.clear();
+  pending_subkey_request_.reset();
+}
+
+void SubKeyRequester::CancelPendingGetSubKeys() {
+  pending_subkey_region_code_.clear();
+  pending_subkey_request_.reset();
+}
+
+}  // namespace payments