Add PeripheralBatteryObserver

chrome/browser/chromeos/power/peripheral_battery_observer.cc

+// Copyright (c) 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 <vector>
+
+#include "chrome/browser/chromeos/power/peripheral_battery_observer.h"
+
+#include "ash/shell.h"
+#include "base/bind.h"
+#include "base/string16.h"
+#include "base/stringprintf.h"
+#include "base/strings/string_split.h"
+#include "base/utf_string_conversions.h"
+#include "chrome/browser/browser_process.h"
+#include "chrome/browser/notifications/notification.h"
+#include "chrome/browser/notifications/notification_ui_manager.h"
+#include "chrome/browser/profiles/profile_manager.h"
+#include "chromeos/dbus/dbus_thread_manager.h"
+#include "device/bluetooth/bluetooth_adapter_factory.h"
+#include "device/bluetooth/bluetooth_device.h"
+#include "grit/ash_strings.h"
+#include "grit/theme_resources.h"
+#include "ui/base/l10n/l10n_util.h"
+#include "ui/base/resource/resource_bundle.h"
+#include "ui/gfx/image/image.h"
+
+namespace chromeos {
+
+namespace {
+
+// When a peripheral device's battery level is <= kLowBatteryLevel, consider
+// it to be in low battery condition.
+const int kLowBatteryLevel = 15;

[Daniel Erat, 2013/04/09 02:06:18]

nit: add blank line after this

[Yufeng Shen (Slow to review), 2013/04/10 05:54:08]

Done.

+// Don't show 2 low battery notification within |kNotificationIntervalSec|
+// seconds.
+const int kNotificationIntervalSec = 60;

[Daniel Erat, 2013/04/09 02:06:18]

nit: add blank line after this

[Yufeng Shen (Slow to review), 2013/04/10 05:54:08]

Done.

+// HID Bluetooth device's battery sysfs entry path looks like
+// "/sys/class/power_supply/hid-AA:BB:CC:DD:EE:FF-battery".
+// Here the bluetooth address is showed in reverse order and its true
+// address "FF:EE:DD:CC:BB:AA".
+const char kHIDBatteryPathHeader[] = "/sys/class/power_supply/hid-";

[Daniel Erat, 2013/04/09 02:06:18]

instead of "header" and "end", how about "prefix" and "suffix"?

[Yufeng Shen (Slow to review), 2013/04/10 05:54:08]

Done.

+const char kHIDBatteryPathEnd[] = "-battery";
+
+class PeripheralBatteryNotificationDelegate : public NotificationDelegate {
+ public:
+  explicit PeripheralBatteryNotificationDelegate(const std::string& id)
+      : id_(id) {}
+
+  // Overridden from NotificationDelegate:
+  virtual void Display() OVERRIDE {}
+  virtual void Error() OVERRIDE {}
+  virtual void Close(bool by_user) OVERRIDE {}
+  virtual void Click() OVERRIDE {}
+  virtual std::string id() const OVERRIDE { return id_; }
+  // A NULL return value prevents loading image from URL. It is OK since our
+  // implementation loads image from system resource bundle.
+  virtual content::RenderViewHost* GetRenderViewHost() const OVERRIDE {
+    return NULL;
+  }
+
+ private:
+  const std::string id_;
+
+  DISALLOW_COPY_AND_ASSIGN(PeripheralBatteryNotificationDelegate);
+};
+
+}  // namespace
+
+PeripheralBatteryObserver::PeripheralBatteryObserver()
+    : weakptr_factory_(ALLOW_THIS_IN_INITIALIZER_LIST(
+          new base::WeakPtrFactory<PeripheralBatteryObserver>(this))) {
+  DBusThreadManager::Get()->GetPowerManagerClient()->AddObserver(this);
+  device::BluetoothAdapterFactory::GetAdapter(
+      base::Bind(&PeripheralBatteryObserver::InitializeOnBluetoothReady,
+                 weakptr_factory_->GetWeakPtr()));
+}
+
+PeripheralBatteryObserver::~PeripheralBatteryObserver() {
+  if (bluetooth_adapter_.get())
+    bluetooth_adapter_->RemoveObserver(this);
+  DBusThreadManager::Get()->GetPowerManagerClient()->RemoveObserver(this);
+}
+
+void PeripheralBatteryObserver::InitializeOnBluetoothReady(
+    scoped_refptr<device::BluetoothAdapter> adapter) {
+  bluetooth_adapter_ = adapter;
+  CHECK(bluetooth_adapter_);
+  bluetooth_adapter_->AddObserver(this);
+}
+
+void PeripheralBatteryObserver::PeripheralBatteryStatusReceived(
+    const std::string& path,
+    const std::string& name,
+    int level) {
+  std::string key;

[Daniel Erat, 2013/04/09 02:06:18]

rename this variable to "address" to make it clearer what it contains

[Yufeng Shen (Slow to review), 2013/04/10 05:54:08]

Done.

+  if (IsBluetoothHIDBattery(path)) {
+      // For HID bluetooh device, device address is used as key to index
+      // BatteryInfo.
+      key = ExtractBluetoothAddress(path);
+  } else {
+    LOG(ERROR) << "Unsupported battery path " << path;
+    return;
+  }
+
+  if (level < -1 || level > 100) {
+    LOG(ERROR) << "Invalid battery level " << level
+               << " for device " << name << " at path " << path;
+    return;
+  }
+  // If unknown battery level received, cancel any existing notification.
+  if (level == -1) {
+    CancelNotification(key);
+    return;
+  }
+
+  // Post the notification in 2 cases:
+  // 1. It's the first time the battery level is received, and it is
+  //    below kLowBatteryLevel.
+  // 2. The battery level is in record and it drops below kLowBatteryLevel.
+  if (batteries_.find(key) == batteries_.end()) {
+    BatteryInfo battery(name, level, base::TimeTicks(), base::TimeTicks::Now());
+    if (level <= kLowBatteryLevel) {
+      if (PostNotification(key, battery))
+        battery.set_notification_timestamp(base::TimeTicks::Now());
+    }
+    batteries_[key] = battery;
+  } else {
+    BatteryInfo* battery = &batteries_[key];
+    battery->set_name(name);
+    int old_level = battery->level();
+    battery->set_level(level);
+    battery->set_update_timestamp(base::TimeTicks::Now());
+    if (old_level > kLowBatteryLevel && level <= kLowBatteryLevel) {
+      if (PostNotification(key, *battery))
+        battery->set_notification_timestamp(base::TimeTicks::Now());
+    }
+  }
+}
+
+void PeripheralBatteryObserver::DeviceChanged(device::BluetoothAdapter* adapter,
+                                              device::BluetoothDevice* device) {
+  if (!device->IsPaired()) {

[Daniel Erat, 2013/04/09 02:06:18]

nit: remove curly braces since the statement is a single line

[Yufeng Shen (Slow to review), 2013/04/10 05:54:08]

Done.

+    RemoveBattery(device->GetAddress());
+  }
+}
+
+void PeripheralBatteryObserver::DeviceRemoved(device::BluetoothAdapter* adapter,
+                                              device::BluetoothDevice* device) {
+  RemoveBattery(device->GetAddress());
+}
+
+bool PeripheralBatteryObserver::IsBluetoothHIDBattery(const std::string& path) {
+  return StartsWithASCII(path, kHIDBatteryPathHeader, false) &&
+      EndsWith(path, kHIDBatteryPathEnd, false);
+}
+
+std::string PeripheralBatteryObserver::ExtractBluetoothAddress(
+    const std::string& path) {
+    int header_size = sizeof(kHIDBatteryPathHeader);

[Daniel Erat, 2013/04/09 02:06:18]

indent this line and the following ones two spaces, not four

[Yufeng Shen (Slow to review), 2013/04/10 05:54:08]

Done.

+    int end_size = sizeof(kHIDBatteryPathEnd);

[Daniel Erat, 2013/04/09 02:06:18]

this makes me nervous.  will it break if someone changes the constants to be
char* instead for some reason?  it might be safer to use strlen, even if it's
slower.

[Yufeng Shen (Slow to review), 2013/04/10 05:54:08]

Done.

+    int key_len = path.size() - (header_size - 1) - (end_size - 1);

[Daniel Erat, 2013/04/09 02:06:18]

this makes me nervous.  return early if key_len <= 0?

[Yufeng Shen (Slow to review), 2013/04/10 05:54:08]

Done.

+    std::string reverse_address = path.substr(header_size - 1, key_len);
+    StringToLowerASCII(&reverse_address);
+    std::vector<std::string> result;
+    base::SplitString(reverse_address, ':', &result);
+    std::reverse(result.begin(), result.end());
+    std::string address = JoinString(result, ':');
+    return address;
+}
+
+void PeripheralBatteryObserver::RemoveBattery(const std::string& key) {
+  std::string key_lowercase = key;
+  StringToLowerASCII(&key_lowercase);
+  if (batteries_.find(key_lowercase) != batteries_.end()) {

[Daniel Erat, 2013/04/09 02:06:18]

if you aren't going to save the iterator to make the call to erase() faster,
it's easier to just use batteries_.count(key_lowercase) here

[Yufeng Shen (Slow to review), 2013/04/10 05:54:08]

Done.

+    batteries_.erase(key_lowercase);
+    CancelNotification(key_lowercase);
+  }
+}
+
+bool PeripheralBatteryObserver::PostNotification(const std::string& id,
+                                                 const BatteryInfo& battery) {
+  // Only post notification if kNotificationInterval seconds have passed since
+  // last notification showed, avoiding the case where the battery level
+  // oscillates around the threshold level.
+  if (base::TimeTicks::Now() - battery.last_notification_timestamp() <
+      base::TimeDelta::FromSeconds(kNotificationIntervalSec))
+    return false;
+
+  NotificationUIManager* notification_manager =
+      g_browser_process->notification_ui_manager();
+
+  base::string16 string_text = l10n_util::GetStringFUTF16Int(
+      IDS_ASH_LOW_PERIPHERAL_BATTERY_NOTIFICATION_TEXT,
+      battery.level());
+
+  Notification notification(
+      // TODO(mukai): add SYSTEM priority and use here.
+      GURL(),
+      ui::ResourceBundle::GetSharedInstance().GetImageNamed(
+          IDR_NOTIFICATION_PERIPHERAL_BATTERY_LOW),
+      UTF8ToUTF16(battery.name()),
+      string_text,
+      WebKit::WebTextDirectionDefault,
+      string16(),
+      UTF8ToUTF16(id),
+      new PeripheralBatteryNotificationDelegate(id));
+
+  notification_manager->Add(notification,
+                            ProfileManager::GetDefaultProfileOrOffTheRecord());
+
+  return true;
+}
+
+void PeripheralBatteryObserver::CancelNotification(const std::string& id) {
+  g_browser_process->notification_ui_manager()->CancelById(id);
+}
+
+
+}  // namespace chromeos