chrome.bluetoothLowEnergy: Implement getService and getServices.

chrome/browser/extensions/api/bluetooth_low_energy/bluetooth_low_energy_api.cc

 // Copyright 2014 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 "chrome/browser/extensions/api/bluetooth_low_energy/bluetooth_low_energy_api.h"
 
+#include "base/bind.h"
+#include "base/lazy_instance.h"
+#include "base/strings/stringprintf.h"
+#include "chrome/browser/extensions/api/bluetooth_low_energy/bluetooth_low_energy_event_router.h"
+#include "chrome/common/extensions/api/bluetooth_low_energy.h"
+#include "content/public/browser/browser_thread.h"
+#include "extensions/browser/event_router.h"
+
+using content::BrowserContext;
+using content::BrowserThread;
+
+namespace apibtle = extensions::api::bluetooth_low_energy;
+
+namespace {
+
+const char kErrorAdapterNotInitialized[] =
+    "Could not initialize Bluetooth adapter.";
+const char kErrorDeviceNotFoundFormat[] =
+    "Device with address \"%s\" not found.";
+const char kErrorServiceNotFoundFormat[] = "Service with ID \"%s\" not found.";
+const char kErrorPlatformNotSupported[] =
+    "This operation is not supported on the current platform";
+
+extensions::BluetoothLowEnergyEventRouter* GetEventRouter(
+    BrowserContext* context) {
+  DCHECK(BrowserThread::CurrentlyOn(BrowserThread::UI));
+  return extensions::BluetoothLowEnergyAPI::Get(context)->event_router();
+}
+
+}  // namespace
+
 namespace extensions {
+
+static base::LazyInstance<BrowserContextKeyedAPIFactory<BluetoothLowEnergyAPI> >
+    g_factory = LAZY_INSTANCE_INITIALIZER;
+
+// static
+BrowserContextKeyedAPIFactory<BluetoothLowEnergyAPI>*
+BluetoothLowEnergyAPI::GetFactoryInstance() {
+  return g_factory.Pointer();
+}
+
+// static
+BluetoothLowEnergyAPI* BluetoothLowEnergyAPI::Get(BrowserContext* context) {
+  DCHECK(BrowserThread::CurrentlyOn(BrowserThread::UI));
+  return GetFactoryInstance()->Get(context);
+}
+
+BluetoothLowEnergyAPI::BluetoothLowEnergyAPI(BrowserContext* context)
+    : event_router_(new BluetoothLowEnergyEventRouter(context)),
+      browser_context_(context) {
+  DCHECK(BrowserThread::CurrentlyOn(BrowserThread::UI));
+}
+
+BluetoothLowEnergyAPI::~BluetoothLowEnergyAPI() {
+}
+
+void BluetoothLowEnergyAPI::Shutdown() {
+  DCHECK(BrowserThread::CurrentlyOn(BrowserThread::UI));
+}
+
 namespace api {
 
-bool BluetoothLowEnergyGetServiceFunction::RunImpl() {
-  // TODO(armansito): Implement.
-  SetError("Call not supported.");
-  return false;
-}
-
-bool BluetoothLowEnergyGetServicesFunction::RunImpl() {
-  // TODO(armansito): Implement.
-  SetError("Call not supported.");
-  return false;
-}
-
-bool BluetoothLowEnergyGetCharacteristicFunction::RunImpl() {
-  // TODO(armansito): Implement.
-  SetError("Call not supported.");
-  return false;
-}
-
-bool BluetoothLowEnergyGetCharacteristicsFunction::RunImpl() {
-  // TODO(armansito): Implement.
-  SetError("Call not supported.");
-  return false;
-}
-
-bool BluetoothLowEnergyGetIncludedServicesFunction::RunImpl() {
-  // TODO(armansito): Implement.
-  SetError("Call not supported.");
-  return false;
-}
-
-bool BluetoothLowEnergyGetDescriptorFunction::RunImpl() {
-  // TODO(armansito): Implement.
-  SetError("Call not supported.");
-  return false;
-}
-
-bool BluetoothLowEnergyGetDescriptorsFunction::RunImpl() {
-  // TODO(armansito): Implement.
-  SetError("Call not supported.");
-  return false;
-}
-
-bool BluetoothLowEnergyReadCharacteristicValueFunction::RunImpl() {
-  // TODO(armansito): Implement.
-  SetError("Call not supported.");
-  return false;
-}
-
-bool BluetoothLowEnergyWriteCharacteristicValueFunction::RunImpl() {
-  // TODO(armansito): Implement.
-  SetError("Call not supported.");
-  return false;
-}
-
-bool BluetoothLowEnergyReadDescriptorValueFunction::RunImpl() {
-  // TODO(armansito): Implement.
-  SetError("Call not supported.");
-  return false;
-}
-
-bool BluetoothLowEnergyWriteDescriptorValueFunction::RunImpl() {
-  // TODO(armansito): Implement.
-  SetError("Call not supported.");
-  return false;
+BluetoothLowEnergyExtensionFunction::BluetoothLowEnergyExtensionFunction()
+    : weak_ptr_factory_(this) {
+}
+
+BluetoothLowEnergyExtensionFunction::~BluetoothLowEnergyExtensionFunction() {
+}
+
+bool BluetoothLowEnergyExtensionFunction::RunImpl() {
+  DCHECK(BrowserThread::CurrentlyOn(BrowserThread::UI));
+
+  BluetoothLowEnergyEventRouter* event_router =
+      GetEventRouter(browser_context());
+  if (!event_router->IsBluetoothSupported()) {
+    SetError(kErrorPlatformNotSupported);
+    return false;
+  }
+
+  if (!event_router->InitializeAdapterAndInvokeCallback(
+          base::Bind(&BluetoothLowEnergyExtensionFunction::DoWork,
+                     weak_ptr_factory_.GetWeakPtr()))) {

[rpaquay, 2014/04/24 20:38:45]

Does this work? I would think you should pass "this" (as ExtensionFunction are
ref-counted). AFAIK, the extension function instance with be released right
after RunImpl if you don't use "this" here (see
https://code.google.com/p/chromium/codesearch#chromium/src/extensions/browser...).

[armansito, 2014/04/24 22:02:00]

I'm confused, if you actually pass "this" here and the object gets deleted
before the callback gets called, wouldn't that be an invalid access?

[rpaquay, 2014/04/24 22:12:46]

AFAIK:

1) If you pass "this", Bind calls "this->AddRef()" to keep the object alive
until after the callback is invoked.
2) If you pass "weak_ptr_factory" in this case, the extension function will be
almost immediately deleted because the "Dispatch()" function has a
"scoped_refptr" to it.

Basically, the way I understand the current code is that, in case
InitilizeAdapterAndInvokeCallback" is truly asynchronous, the callback will
actually never be called because the extension function will be deleted right
away.

[armansito, 2014/04/24 22:38:33]

Ah got it, I didn't realize that ExtensionFunction was refcounted, thanks for
catching that. Changed the code to pass 'this'.

+    SetError(kErrorAdapterNotInitialized);
+    return false;
+  }
+
+  return true;
+}
+
+void BluetoothLowEnergyGetServiceFunction::DoWork() {
+  DCHECK(BrowserThread::CurrentlyOn(BrowserThread::UI));
+
+  BluetoothLowEnergyEventRouter* event_router =
+      GetEventRouter(browser_context());
+
+  // The adapter must be initialized at this point, but return an error instead
+  // of asserting.
+  if (!event_router->HasAdapter()) {
+    SetError(kErrorAdapterNotInitialized);
+    SendResponse(false);
+    return;
+  }
+
+  scoped_ptr<apibtle::GetService::Params> params(
+      apibtle::GetService::Params::Create(*args_));
+  EXTENSION_FUNCTION_VALIDATE(params.get() != NULL);
+
+  std::string service_id = params->service_id;
+
+  apibtle::Service service;
+  if (!event_router->GetService(service_id, &service)) {
+    SetError(
+        base::StringPrintf(kErrorServiceNotFoundFormat, service_id.c_str()));
+    SendResponse(false);
+    return;
+  }
+
+  SetResult(service.ToValue().release());
+  SendResponse(true);
+}
+
+void BluetoothLowEnergyGetServicesFunction::DoWork() {
+  DCHECK(BrowserThread::CurrentlyOn(BrowserThread::UI));
+
+  BluetoothLowEnergyEventRouter* event_router =
+      GetEventRouter(browser_context());
+
+  // The adapter must be initialized at this point, but return an error instead
+  // of asserting.
+  if (!event_router->HasAdapter()) {
+    SetError(kErrorAdapterNotInitialized);
+    SendResponse(false);
+    return;
+  }
+
+  scoped_ptr<apibtle::GetServices::Params> params(
+      apibtle::GetServices::Params::Create(*args_));
+  EXTENSION_FUNCTION_VALIDATE(params.get() != NULL);
+
+  std::string device_address = params->device_address;
+
+  base::ListValue* service_list = event_router->GetServices(device_address);
+  if (!service_list) {
+    SetError(
+        base::StringPrintf(kErrorDeviceNotFoundFormat, device_address.c_str()));
+    SendResponse(false);
+    return;
+  }
+
+  SetResult(service_list);
+  SendResponse(true);
+}
+
+void BluetoothLowEnergyGetCharacteristicFunction::DoWork() {
+  // TODO(armansito): Implement.
+  SetError("Call not supported.");
+  SendResponse(false);
+}
+
+void BluetoothLowEnergyGetCharacteristicsFunction::DoWork() {
+  // TODO(armansito): Implement.
+  SetError("Call not supported.");
+  SendResponse(false);
+}
+
+void BluetoothLowEnergyGetIncludedServicesFunction::DoWork() {
+  // TODO(armansito): Implement.
+  SetError("Call not supported.");
+  SendResponse(false);
+}
+
+void BluetoothLowEnergyGetDescriptorFunction::DoWork() {
+  // TODO(armansito): Implement.
+  SetError("Call not supported.");
+  SendResponse(false);
+}
+
+void BluetoothLowEnergyGetDescriptorsFunction::DoWork() {
+  // TODO(armansito): Implement.
+  SetError("Call not supported.");
+  SendResponse(false);
+}
+
+void BluetoothLowEnergyReadCharacteristicValueFunction::DoWork() {
+  // TODO(armansito): Implement.
+  SetError("Call not supported.");
+  SendResponse(false);
+}
+
+void BluetoothLowEnergyWriteCharacteristicValueFunction::DoWork() {
+  // TODO(armansito): Implement.
+  SetError("Call not supported.");
+  SendResponse(false);
+}
+
+void BluetoothLowEnergyReadDescriptorValueFunction::DoWork() {
+  // TODO(armansito): Implement.
+  SetError("Call not supported.");
+  SendResponse(false);
+}
+
+void BluetoothLowEnergyWriteDescriptorValueFunction::DoWork() {
+  // TODO(armansito): Implement.
+  SetError("Call not supported.");
+  SendResponse(false);
 }
 
 }  // namespace api
 }  // namespace extensions