bluetooth: Require context is connected for getCharacteristic(s)

third_party/WebKit/Source/modules/bluetooth/BluetoothRemoteGATTService.cpp

 // Copyright 2015 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/bluetooth/BluetoothRemoteGATTService.h"
 
 #include "bindings/core/v8/CallbackPromiseAdapter.h"
 #include "bindings/core/v8/ScriptPromise.h"
 #include "bindings/core/v8/ScriptPromiseResolver.h"
 #include "core/dom/DOMException.h"
 #include "core/dom/ExceptionCode.h"
 #include "core/inspector/ConsoleMessage.h"
 #include "modules/bluetooth/BluetoothError.h"
 #include "modules/bluetooth/BluetoothRemoteGATTCharacteristic.h"
 #include "modules/bluetooth/BluetoothSupplement.h"
 #include "modules/bluetooth/BluetoothUUID.h"
 #include "public/platform/modules/bluetooth/WebBluetooth.h"
 #include "wtf/PtrUtil.h"
 #include <memory>
 
 namespace blink {
 
+namespace {
+
+const char kGATTServerDisconnected[] =
+    "GATT Server disconnected while retrieving characteristics.";
+const char kGATTServerNotConnected[] =
+    "GATT Server is disconnected. Cannot retrieve characteristics.";
+
+}  // namespace
+
 BluetoothRemoteGATTService::BluetoothRemoteGATTService(
     std::unique_ptr<WebBluetoothRemoteGATTService> webService,
     BluetoothDevice* device)
     : m_webService(std::move(webService)), m_device(device) {}
 
 BluetoothRemoteGATTService* BluetoothRemoteGATTService::take(
     ScriptPromiseResolver*,
     std::unique_ptr<WebBluetoothRemoteGATTService> webService,
     BluetoothDevice* device) {
   if (!webService) {
     return nullptr;
   }
   return new BluetoothRemoteGATTService(std::move(webService), device);
 }
 
 DEFINE_TRACE(BluetoothRemoteGATTService) {
   visitor->trace(m_device);
 }
 
 // Class that allows us to resolve the promise with a single Characteristic or
 // with a vector owning the characteristics.
 class GetCharacteristicsCallback
     : public WebBluetoothGetCharacteristicsCallbacks {
  public:
   GetCharacteristicsCallback(
       BluetoothRemoteGATTService* service,
       mojom::blink::WebBluetoothGATTQueryQuantity quantity,
       ScriptPromiseResolver* resolver)
-      : m_service(service), m_quantity(quantity), m_resolver(resolver) {}
+      : m_service(service), m_quantity(quantity), m_resolver(resolver) {
+    // We always check that the device is connected before constructing this
+    // object.
+    CHECK(m_service->device()->gatt()->connected());
+    m_service->device()->gatt()->AddToActiveAlgorithms(m_resolver.get());
+  }
 
   void onSuccess(const WebVector<WebBluetoothRemoteGATTCharacteristicInit*>&
                      webCharacteristics) override {
     if (!m_resolver->getExecutionContext() ||
         m_resolver->getExecutionContext()->activeDOMObjectsAreStopped())
       return;
 
+    // If the resolver is not in the set of ActiveAlgorithms then the frame
+    // disconnected so we reject.
+    if (!m_service->device()->gatt()->RemoveFromActiveAlgorithms(
+            m_resolver.get())) {
+      m_resolver->reject(
+          DOMException::create(NetworkError, kGATTServerDisconnected));
+      return;
+    }
+
     if (m_quantity == mojom::blink::WebBluetoothGATTQueryQuantity::SINGLE) {
       DCHECK_EQ(1u, webCharacteristics.size());
       m_resolver->resolve(BluetoothRemoteGATTCharacteristic::take(
           m_resolver, wrapUnique(webCharacteristics[0]), m_service));
       return;
     }
 
     HeapVector<Member<BluetoothRemoteGATTCharacteristic>> characteristics;
     characteristics.reserveInitialCapacity(webCharacteristics.size());
     for (WebBluetoothRemoteGATTCharacteristicInit* webCharacteristic :
          webCharacteristics) {
       characteristics.append(BluetoothRemoteGATTCharacteristic::take(
           m_resolver, wrapUnique(webCharacteristic), m_service));
     }
     m_resolver->resolve(characteristics);
   }
 
   void onError(
       int32_t
           error /* Corresponds to WebBluetoothError in web_bluetooth.mojom */)
       override {
     if (!m_resolver->getExecutionContext() ||
         m_resolver->getExecutionContext()->activeDOMObjectsAreStopped())
       return;
+    m_service->device()->gatt()->RemoveFromActiveAlgorithms(m_resolver.get());

[Jeffrey Yasskin, 2016/10/06 17:50:32]

https://webbluetoothcg.github.io/web-bluetooth/#connection-checking-wrapper says
to replace the real error with a NetworkError if we've disconnected during the
operation. We get there through the
https://webbluetoothcg.github.io/web-bluetooth/#query-the-bluetooth-cache step
of https://webbluetoothcg.github.io/web-bluetooth/#getgattchildren.

I think that's even the right behavior. ;-)

[ortuno, 2016/10/07 04:45:59]

Done.

     m_resolver->reject(BluetoothError::take(m_resolver, error));
   }
 
  private:
   Persistent<BluetoothRemoteGATTService> m_service;
   mojom::blink::WebBluetoothGATTQueryQuantity m_quantity;
   Persistent<ScriptPromiseResolver> m_resolver;

[Jeffrey Yasskin, 2016/10/06 17:50:32]

Can you make this const, to be clear that we always add and remove the same
object from the ActiveAlgorithms set?

[ortuno, 2016/10/07 04:45:59]

Done.

 };
 
 ScriptPromise BluetoothRemoteGATTService::getCharacteristic(
     ScriptState* scriptState,
     const StringOrUnsignedLong& characteristic,
     ExceptionState& exceptionState) {
   String characteristicUUID =
       BluetoothUUID::getCharacteristic(characteristic, exceptionState);
   if (exceptionState.hadException())
     return exceptionState.reject(scriptState);
@@ skipping 21 matching lines @@
     ScriptState* scriptState,
     ExceptionState&) {
   return getCharacteristicsImpl(
       scriptState, mojom::blink::WebBluetoothGATTQueryQuantity::MULTIPLE);
 }
 
 ScriptPromise BluetoothRemoteGATTService::getCharacteristicsImpl(
     ScriptState* scriptState,
     mojom::blink::WebBluetoothGATTQueryQuantity quantity,
     String characteristicsUUID) {
+  if (!device()->gatt()->connected()) {
+    return ScriptPromise::rejectWithDOMException(
+        scriptState,
+        DOMException::create(NetworkError, kGATTServerNotConnected));
+  }
+
   ScriptPromiseResolver* resolver = ScriptPromiseResolver::create(scriptState);
   ScriptPromise promise = resolver->promise();
 
   WebBluetooth* webbluetooth =
       BluetoothSupplement::fromScriptState(scriptState);
   webbluetooth->getCharacteristics(
       m_webService->serviceInstanceID, static_cast<int32_t>(quantity),
       characteristicsUUID,
       new GetCharacteristicsCallback(this, quantity, resolver));
 
   return promise;
 }
 
 }  // namespace blink