bluetooth: Add histograms and logging for requestDevice()

content/browser/bluetooth/bluetooth_dispatcher_host.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.
 
 // NETWORK_ERROR Note:
 // When a device can't be found in the BluetoothAdapter, that generally
 // indicates that it's gone out of range. We reject with a NetworkError in that
 // case.
 // https://webbluetoothchrome.github.io/web-bluetooth/#dom-bluetoothdevice-connectgatt
 
 #include "content/browser/bluetooth/bluetooth_dispatcher_host.h"
 
-#include "base/metrics/histogram.h"
+#include "base/hash.h"
+#include "base/metrics/histogram_macros.h"
+#include "base/metrics/sparse_histogram.h"
 #include "base/strings/utf_string_conversions.h"
 #include "content/browser/bad_message.h"
 #include "content/browser/frame_host/render_frame_host_impl.h"
 #include "content/common/bluetooth/bluetooth_messages.h"
 #include "device/bluetooth/bluetooth_adapter.h"
 #include "device/bluetooth/bluetooth_adapter_factory.h"
 #include "device/bluetooth/bluetooth_device.h"
 #include "device/bluetooth/bluetooth_discovery_session.h"
 #include "device/bluetooth/bluetooth_gatt_characteristic.h"
 #include "device/bluetooth/bluetooth_gatt_service.h"
@@ skipping 27 matching lines @@
   NO_MATCHING_DEVICES_FOUND = 5,
   BLUETOOTH_ADAPTER_NOT_PRESENT = 6,
   BLUETOOTH_ADAPTER_OFF = 7,
   // NOTE: Add new requestDevice() outcomes immediately above this line. Make
   // sure to update the enum list in
   // tools/metrics/histogram/histograms.xml accordingly.
   COUNT
 };
 
 void RecordRequestDeviceOutcome(UMARequestDeviceOutcome outcome) {
-  UMA_HISTOGRAM_ENUMERATION("Bluetooth.RequestDevice.Outcome",
+  UMA_HISTOGRAM_ENUMERATION("Bluetooth.Web.RequestDevice.Outcome",
                             static_cast<int>(outcome),
                             static_cast<int>(UMARequestDeviceOutcome::COUNT));
 }
 
+int HashUUID(const BluetoothUUID& service) {
+  uint32 data = base::Hash(service.canonical_value());

[scheib, 2015/08/12 21:00:36]

base::Hash uses SuperFastHash, which has a lot of collisions for shorter
strings. We avoided using it in GetPeripheralHashAddress
https://code.google.com/p/chromium/codesearch#chromium/src/device/bluetooth/b...

http://programmers.stackexchange.com/questions/49550/which-hashing-algorithm-...
discusses this some. OK, all that said I think base::Hash is still probably what
we want to use here.

[ortuno, 2015/08/12 21:16:26]

SuperFastHash seems to be OK for UUIDs i.e. 4 collisions in 216,553 UUIDs

+
+  // Strip off the signed bit because UMA doesn't support negative values,
+  // but takes a signed int as input.
+  return static_cast<int>(data & 0x7fffffff);
+}
+
+void RecordRequestDeviceFilters(
+    const std::vector<content::BluetoothScanFilter>& filters) {
+  UMA_HISTOGRAM_COUNTS_100("Bluetooth.Web.RequestDevice.Filters.Count",
+                           filters.size());
+  for (const content::BluetoothScanFilter& filter : filters) {
+    UMA_HISTOGRAM_COUNTS_100("Bluetooth.Web.RequestDevice.FilterSize",
+                             filter.services.size());
+    for (const BluetoothUUID& service : filter.services) {
+      UMA_HISTOGRAM_SPARSE_SLOWLY(
+          "Bluetooth.Web.RequestDevice.Filters.Services", HashUUID(service));
+    }
+  }
+}
+
+void RecordRequestDeviceOptionalServices(
+    const std::vector<BluetoothUUID>& optional_services) {
+  UMA_HISTOGRAM_COUNTS_100("Bluetooth.Web.RequestDevice.OptionalServices.Count",
+                           optional_services.size());
+  for (const BluetoothUUID& service : optional_services) {
+    UMA_HISTOGRAM_SPARSE_SLOWLY(
+        "Bluetooth.Web.RequestDevice.OptionalServices.Services",
+        HashUUID(service));
+  }
+}
+
+void RecordUnionOfServices(
+    const std::vector<content::BluetoothScanFilter>& filters,
+    const std::vector<BluetoothUUID>& optional_services) {
+  std::set<BluetoothUUID> union_of_services(optional_services.begin(),
+                                            optional_services.end());
+
+  for (const content::BluetoothScanFilter& filter : filters)
+    union_of_services.insert(filter.services.begin(), filter.services.end());
+
+  UMA_HISTOGRAM_COUNTS_100("Bluetooth.Web.RequestDevice.UnionOfServices.Count",
+                           union_of_services.size());
+}
+
 enum class UMAWebBluetoothFunction {
   REQUEST_DEVICE,
   CONNECT_GATT,
   GET_PRIMARY_SERVICE,
   GET_CHARACTERISTIC,
   CHARACTERISTIC_READ_VALUE,
   CHARACTERISTIC_WRITE_VALUE,
   // NOTE: Add new actions immediately above this line. Make sure to update the
   // enum list in tools/metrics/histogram/histograms.xml accordingly.
   COUNT
@@ skipping 188 matching lines @@
 }
 
 void BluetoothDispatcherHost::OnRequestDevice(
     int thread_id,
     int request_id,
     int frame_routing_id,
     const std::vector<BluetoothScanFilter>& filters,
     const std::vector<BluetoothUUID>& optional_services) {
   DCHECK_CURRENTLY_ON(content::BrowserThread::UI);
   RecordWebBluetoothFunctionCall(UMAWebBluetoothFunction::REQUEST_DEVICE);
+  RecordRequestDeviceFilters(filters);
+  RecordRequestDeviceOptionalServices(optional_services);
+  RecordUnionOfServices(filters, optional_services);
+
+  VLOG(1) << "requestDevice called with the following filters: ";
+  for (const BluetoothScanFilter& filter : filters) {
+    VLOG(1) << "[";

[scheib, 2015/08/12 21:00:35]

Maybe
"\t[" and
"\t\t" << service.value()

[ortuno, 2015/08/12 21:16:26]

Done.

+    for (const BluetoothUUID& service : filter.services)
+      VLOG(1) << "\t" << service.value();
+    VLOG(1) << "]";
+  }
+
+  VLOG(1) << "requestDevice called with the following optional services: ";
+  for (const BluetoothUUID& service : optional_services)
+    VLOG(1) << "\t" << service.value();
 
   RenderFrameHostImpl* render_frame_host =
       RenderFrameHostImpl::FromID(render_process_id_, frame_routing_id);
 
   if (!render_frame_host) {
     DLOG(WARNING)
         << "Got a requestDevice IPC without a matching RenderFrameHost: "
         << render_process_id_ << ", " << frame_routing_id;
     RecordRequestDeviceOutcome(UMARequestDeviceOutcome::NO_RENDER_FRAME);
     Send(new BluetoothMsg_RequestDeviceError(
@@ skipping 38 matching lines @@
       request_device_sessions_.erase(std::make_pair(thread_id, request_id));
       return;
     }
     adapter_->StartDiscoverySessionWithFilter(
         ComputeScanFilter(filters),
         base::Bind(&BluetoothDispatcherHost::OnDiscoverySessionStarted,
                    weak_ptr_factory_.GetWeakPtr(), thread_id, request_id),
         base::Bind(&BluetoothDispatcherHost::OnDiscoverySessionStartedError,
                    weak_ptr_factory_.GetWeakPtr(), thread_id, request_id));
   } else {
-    DLOG(WARNING) << "No BluetoothAdapter. Can't serve requestDevice.";
+    VLOG(1) << "No BluetoothAdapter. Can't serve requestDevice.";
     RecordRequestDeviceOutcome(UMARequestDeviceOutcome::NO_BLUETOOTH_ADAPTER);
     Send(new BluetoothMsg_RequestDeviceError(
         thread_id, request_id, WebBluetoothError::NoBluetoothAdapter));
   }
   return;
 }
 
 void BluetoothDispatcherHost::OnConnectGATT(
     int thread_id,
     int request_id,
@@ skipping 289 matching lines @@
               device->GetUUIDs()));  // uuids
       RecordRequestDeviceOutcome(UMARequestDeviceOutcome::SUCCESS);
       Send(new BluetoothMsg_RequestDeviceSuccess(thread_id, request_id,
                                                  device_ipc));
       request_device_sessions_.erase(session);
       return;
     }
   }
   RecordRequestDeviceOutcome(
       UMARequestDeviceOutcome::NO_MATCHING_DEVICES_FOUND);
+  VLOG(1) << "No matching Bluetooth Devices found";
   Send(new BluetoothMsg_RequestDeviceError(thread_id, request_id,
                                            WebBluetoothError::NoDevicesFound));
   request_device_sessions_.erase(session);
 }
 
 void BluetoothDispatcherHost::OnDiscoverySessionStoppedError(int thread_id,
                                                              int request_id) {
   DCHECK_CURRENTLY_ON(BrowserThread::UI);
   DLOG(WARNING) << "BluetoothDispatcherHost::OnDiscoverySessionStoppedError";
   RecordRequestDeviceOutcome(UMARequestDeviceOutcome::DISCOVERY_STOP_FAILED);
@@ skipping 82 matching lines @@
 
 void BluetoothDispatcherHost::OnWriteValueFailed(
     int thread_id,
     int request_id,
     device::BluetoothGattService::GattErrorCode error_code) {
   Send(new BluetoothMsg_WriteCharacteristicValueError(
       thread_id, request_id, TranslateGATTError(error_code)));
 }
 
 }  // namespace content