[CrOS Tether] Create HostScanCache, which caches scan results and inserts them into the network sta…

chromeos/components/tether/fake_host_scan_cache.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 "chromeos/components/tether/fake_host_scan_cache.h"
+
+#include "chromeos/components/tether/tether_host_response_recorder.h"
+
+namespace chromeos {
+
+namespace tether {
+
+namespace {
+
+// Shared among all FakeHostScanCache instances. This pointer is not used for
+// anything, but HostScanCache's constructor calls AddObserver() on the
+// TetherHostResponseRecorder* passed to its constructor, so a valid object must
+// be passed to the constructor to prevent a segfault.
+TetherHostResponseRecorder* kTetherHostResponseRecorder = nullptr;
+
+TetherHostResponseRecorder* GetTetherHostResponseRecorder() {
+  if (kTetherHostResponseRecorder)
+    return kTetherHostResponseRecorder;
+
+  kTetherHostResponseRecorder =
+      new TetherHostResponseRecorder(nullptr /* pref_service */);
+  return kTetherHostResponseRecorder;
+}
+
+}  // namespace
+
+FakeHostScanCache::FakeHostScanCache()
+    : HostScanCache(nullptr /* network_state_handler */,
+                    nullptr /* active_host */,
+                    GetTetherHostResponseRecorder(),
+                    nullptr /* device_id_tether_network_guid_map */) {}
+
+FakeHostScanCache::~FakeHostScanCache() {}
+
+const FakeHostScanCache::CacheEntry* FakeHostScanCache::GetCacheEntry(
+    const std::string& tether_network_guid) {
+  auto it = cache_.find(tether_network_guid);
+  if (it == cache_.end())
+    return nullptr;
+
+  return &it->second;
+}
+
+void FakeHostScanCache::SetHostScanResult(
+    const std::string& tether_network_guid,
+    const std::string& device_name,
+    const std::string& carrier,
+    int battery_percentage,
+    int signal_strength) {
+  auto it = cache_.find(tether_network_guid);
+  if (it != cache_.end()) {
+    // If already in the cache, update the cache with new values.
+    it->second.device_name = device_name;
+    it->second.carrier = carrier;
+    it->second.battery_percentage = battery_percentage;
+    it->second.signal_strength = signal_strength;
+    return;
+  }
+
+  // Otherwise, add a new entry.
+  cache_.emplace(
+      tether_network_guid,
+      CacheEntry{device_name, carrier, battery_percentage, signal_strength});
+}
+
+bool FakeHostScanCache::RemoveHostScanResult(
+    const std::string& tether_network_guid) {
+  if (tether_network_guid == active_host_tether_network_guid())
+    return false;
+
+  return cache_.erase(tether_network_guid) > 0;
+}
+
+void FakeHostScanCache::ClearCacheExceptForActiveHost() {
+  auto it = cache_.begin();
+  while (it != cache_.end()) {
+    if (it->first == active_host_tether_network_guid_)
+      it++;
+    else
+      it = cache_.erase(it);
+  }
+}
+
+void FakeHostScanCache::OnPreviouslyConnectedHostIdsChanged() {}
+
+}  // namespace tether
+
+}  // namespace chromeos