[Sensors] Introduce 'unconnected' sensor state

third_party/WebKit/Source/modules/sensor/Sensor.cpp

 // Copyright 2016 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 "modules/sensor/Sensor.h"
 
 #include "core/dom/Document.h"
 #include "core/dom/ExceptionCode.h"
 #include "core/dom/ExecutionContextTask.h"
 #include "core/dom/TaskRunnerHelper.h"
 #include "core/inspector/ConsoleMessage.h"
 #include "core/timing/DOMWindowPerformance.h"
 #include "core/timing/Performance.h"
 #include "device/generic_sensor/public/interfaces/sensor.mojom-blink.h"
 #include "modules/sensor/SensorErrorEvent.h"
 #include "modules/sensor/SensorProviderProxy.h"
 
 using namespace device::mojom::blink;
 
 namespace blink {
 
 Sensor::Sensor(ExecutionContext* executionContext,
                const SensorOptions& sensorOptions,
                ExceptionState& exceptionState,
                SensorType type)
     : ContextLifecycleObserver(executionContext),
       m_sensorOptions(sensorOptions),
       m_type(type),
-      m_state(Sensor::SensorState::Idle),
+      m_state(Sensor::SensorState::Unconnected),
       m_lastUpdateTimestamp(0.0) {
   // Check secure context.
   String errorMessage;
   if (!executionContext->isSecureContext(errorMessage)) {
     exceptionState.throwDOMException(SecurityError, errorMessage);
     return;
   }
 
   // Check top-level browsing context.
   if (!toDocument(executionContext)->domWindow()->frame() ||
@@ skipping 16 matching lines @@
       ConsoleMessage* consoleMessage = ConsoleMessage::create(
           JSMessageSource, InfoMessageLevel, "Frequency is limited to 60 Hz.");
       executionContext->addConsoleMessage(consoleMessage);
     }
   }
 }
 
 Sensor::~Sensor() = default;
 
 void Sensor::start(ScriptState* scriptState, ExceptionState& exceptionState) {
-  if (m_state != Sensor::SensorState::Idle &&
+  if (m_state != Sensor::SensorState::Unconnected &&
+      m_state != Sensor::SensorState::Idle &&
       m_state != Sensor::SensorState::Errored)
     return;
 
   initSensorProxyIfNeeded();
 
   if (!m_sensorProxy) {
     exceptionState.throwDOMException(
         InvalidStateError, "The Sensor is no longer associated to a frame.");
     return;
   }
   m_lastUpdateTimestamp = WTF::monotonicallyIncreasingTime();
   startListening();
 }
 
 void Sensor::stop(ScriptState*, ExceptionState& exceptionState) {
-  if (m_state == Sensor::SensorState::Idle ||
+  if (m_state == Sensor::SensorState::Unconnected ||
+      m_state == Sensor::SensorState::Idle ||
       m_state == Sensor::SensorState::Errored)
     return;
 
   stopListening();
 }
 
 static String ToString(Sensor::SensorState state) {
   switch (state) {
-    case Sensor::SensorState::Idle:
-      return "idle";
+    case Sensor::SensorState::Unconnected:
+      return "unconnected";
     case Sensor::SensorState::Activating:
       return "activating";
     case Sensor::SensorState::Activated:
       return "activated";
+    case Sensor::SensorState::Idle:
+      return "idle";
     case Sensor::SensorState::Errored:
       return "errored";
     default:
       NOTREACHED();
   }
   return "idle";
 }
 
 // Getters
 String Sensor::state() const {
@@ skipping 23 matching lines @@
 }
 
 DEFINE_TRACE(Sensor) {
   visitor->trace(m_sensorProxy);
   ActiveScriptWrappable::trace(visitor);
   ContextLifecycleObserver::trace(visitor);
   EventTargetWithInlineData::trace(visitor);
 }
 
 bool Sensor::hasPendingActivity() const {
-  if (m_state == Sensor::SensorState::Idle ||
+  if (m_state == Sensor::SensorState::Unconnected ||
+      m_state == Sensor::SensorState::Idle ||
       m_state == Sensor::SensorState::Errored)
     return false;
   return getExecutionContext() && hasEventListeners();
 }
 
 auto Sensor::createSensorConfig() -> SensorConfigurationPtr {
   auto result = SensorConfiguration::New();
 
   double defaultFrequency = m_sensorProxy->defaultConfig()->frequency;
   double maximumFrequency = m_sensorProxy->maximumFrequency();
@@ skipping 165 matching lines @@
 }
 
 bool Sensor::canReturnReadings() const {
   if (m_state != Sensor::SensorState::Activated)
     return false;
   DCHECK(m_sensorProxy);
   return m_sensorProxy->reading().timestamp != 0.0;
 }
 
 }  // namespace blink