Create an opaque type for UKM SourceIds.

Bug: 873866
Change-Id: I260aaf9bb1b7162e651d09595231b565d56c1958
Reviewed-on: https://chromium-review.googlesource.com/1173022Reviewed-by: Yaron Friedman <yfriedman@chromium.org>
Reviewed-by: Robert Kaplow (slow) <rkaplow@chromium.org>
Commit-Queue: Steven Holte <holte@chromium.org>
Cr-Commit-Position: refs/heads/master@{#583897}

base/BUILD.gn

@@ -617,6 +617,8 @@ jumbo_component("base") {
     "metrics/sparse_histogram.h",
     "metrics/statistics_recorder.cc",
     "metrics/statistics_recorder.h",
+    "metrics/ukm_source_id.cc",
+    "metrics/ukm_source_id.h",
     "metrics/user_metrics.cc",
     "metrics/user_metrics.h",
     "metrics/user_metrics_action.h",

base/metrics/ukm_source_id.cc

+// Copyright 2018 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 "base/metrics/ukm_source_id.h"
+
+#include "base/atomic_sequence_num.h"
+#include "base/logging.h"
+#include "base/rand_util.h"
+
+namespace base {
+
+namespace {
+
+const int64_t kLowBitsMask = (INT64_C(1) << 32) - 1;
+const int64_t kNumTypeBits = 2;
+const int64_t kTypeMask = (INT64_C(1) << kNumTypeBits) - 1;
+
+}  // namespace
+
+// static
+UkmSourceId UkmSourceId::New() {
+  // Generate some bits which are unique to this process, so we can generate
+  // IDs independently in different processes. IDs generated by this method may
+  // collide, but it should be sufficiently rare enough to not impact data
+  // quality.
+  const static int64_t process_id_bits =
+      static_cast<int64_t>(RandUint64()) & ~kLowBitsMask;
+  // Generate some bits which are unique within the process, using a counter.
+  static AtomicSequenceNumber seq;
+  UkmSourceId local_id = FromOtherId(seq.GetNext() + 1, UkmSourceId::Type::UKM);
+  // Combine the local and process bits to generate a unique ID.
+  return UkmSourceId((local_id.value_ & kLowBitsMask) | process_id_bits);
+}
+
+// static
+UkmSourceId UkmSourceId::FromOtherId(int64_t other_id, UkmSourceId::Type type) {
+  const int64_t type_bits = static_cast<int64_t>(type);
+  DCHECK_EQ(type_bits, type_bits & kTypeMask);
+  // Stores the the type ID in the low bits of the source id, and shift the rest
+  // of the ID to make room.  This could cause the original ID to overflow, but
+  // that should be rare enough that it won't matter for UKM's purposes.
+  return UkmSourceId((other_id << kNumTypeBits) | type_bits);
+}
+
+UkmSourceId::Type UkmSourceId::GetType() const {
+  return static_cast<UkmSourceId::Type>(value_ & kTypeMask);
+}
+
+}  // namespace base

base/metrics/ukm_source_id.h

+// Copyright 2018 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.
+
+#ifndef BASE_METRICS_UKM_SOURCE_ID_H_
+#define BASE_METRICS_UKM_SOURCE_ID_H_
+
+#include <stdint.h>
+
+#include "base/base_export.h"
+
+namespace base {
+
+// An ID used to identify a Source to UKM, for recording information about it.
+// These objects are copyable, assignable, and occupy 64-bits per instance.
+// Prefer passing them by value.
+class BASE_EXPORT UkmSourceId {
+ public:
+  enum class Type : int64_t {
+    UKM = 0,
+    NAVIGATION_ID = 1,
+    APP_ID = 2,
+  };
+
+  // Default constructor has the invalid value.
+  constexpr UkmSourceId() : value_(0) {}
+
+  constexpr UkmSourceId& operator=(UkmSourceId other) {
+    value_ = other.value_;
+    return *this;
+  }
+
+  // Allow identity comparisons.
+  constexpr bool operator==(UkmSourceId other) const {
+    return value_ == other.value_;
+  }
+  constexpr bool operator!=(UkmSourceId other) const {
+    return value_ != other.value_;
+  }
+
+  // Allow coercive comparisons to simplify test migration.
+  // TODO(crbug/873866): Remove these once callers are migrated.
+  constexpr bool operator==(int64_t other) const { return value_ == other; }
+  constexpr bool operator!=(int64_t other) const { return value_ == other; }
+
+  // Extract the Type of the SourceId.
+  Type GetType() const;
+
+  // Return the ID as an int64.
+  constexpr int64_t ToInt64() const { return value_; }
+
+  // Convert an int64 ID value to an ID.
+  static constexpr UkmSourceId FromInt64(int64_t internal_value) {
+    return UkmSourceId(internal_value);
+  }
+
+  // Get a new UKM-Type SourceId, which is unique within the scope of a
+  // browser session.
+  static UkmSourceId New();
+
+  // Utility for converting other unique ids to source ids.
+  static UkmSourceId FromOtherId(int64_t value, Type type);
+
+ private:
+  constexpr explicit UkmSourceId(int64_t value) : value_(value) {}
+  int64_t value_;
+};
+
+constexpr UkmSourceId kInvalidUkmSourceId = UkmSourceId();
+
+}  // namespace base
+
+#endif  // BASE_METRICS_UKM_SOURCE_ID_H_

components/ukm/test_ukm_recorder.h

@@ -36,6 +36,7 @@ class TestUkmRecorder : public UkmRecorderImpl {
   size_t entries_count() const { return entries().size(); }
 
   using UkmRecorderImpl::UpdateSourceURL;
+  using UkmRecorderImpl::RecordOtherURL;
 
   // Gets all recorded UkmSource data.
   const std::map<ukm::SourceId, std::unique_ptr<UkmSource>>& GetSources()

components/ukm/ukm_recorder_impl.h

@@ -84,6 +84,7 @@ class UkmRecorderImpl : public UkmRecorder {
   // UkmRecorder:
   void UpdateSourceURL(SourceId source_id, const GURL& url) override;
   void UpdateAppURL(SourceId source_id, const GURL& url) override;
+  using UkmRecorder::RecordOtherURL;
 
   virtual bool ShouldRestrictToWhitelistedSourceIds() const;
 

services/metrics/public/cpp/ukm_entry_builder_base.cc

@@ -19,6 +19,13 @@ UkmEntryBuilderBase::UkmEntryBuilderBase(ukm::SourceId source_id,
   entry_->event_hash = event_hash;
 }
 
+UkmEntryBuilderBase::UkmEntryBuilderBase(base::UkmSourceId source_id,
+                                         uint64_t event_hash)
+    : entry_(mojom::UkmEntry::New()) {
+  entry_->source_id = source_id.ToInt64();
+  entry_->event_hash = event_hash;
+}
+
 UkmEntryBuilderBase::~UkmEntryBuilderBase() = default;
 
 void UkmEntryBuilderBase::SetMetricInternal(uint64_t metric_hash,

services/metrics/public/cpp/ukm_entry_builder_base.h

@@ -8,6 +8,7 @@
 #include <string>
 
 #include "base/macros.h"
+#include "base/metrics/ukm_source_id.h"
 #include "services/metrics/public/cpp/metrics_export.h"
 #include "services/metrics/public/cpp/ukm_recorder.h"
 #include "services/metrics/public/mojom/ukm_interface.mojom.h"
@@ -27,6 +28,8 @@ class METRICS_EXPORT UkmEntryBuilderBase {
   void Record(UkmRecorder* recorder);
 
  protected:
+  UkmEntryBuilderBase(base::UkmSourceId source_id, uint64_t event_hash);
+  // TODO(crbug/873866): Remove this version once callers are migrated.
   UkmEntryBuilderBase(SourceId source_id, uint64_t event_hash);
 
   // Add metric to the entry. A metric contains a metric hash and value.

services/metrics/public/cpp/ukm_recorder.cc

@@ -31,4 +31,12 @@ ukm::SourceId UkmRecorder::GetNewSourceID() {
   return AssignNewSourceId();
 }
 
+void UkmRecorder::RecordOtherURL(base::UkmSourceId source_id, const GURL& url) {
+  UpdateSourceURL(source_id.ToInt64(), url);
+}
+
+void UkmRecorder::RecordAppURL(base::UkmSourceId source_id, const GURL& url) {
+  UpdateAppURL(source_id.ToInt64(), url);
+}
+
 }  // namespace ukm

services/metrics/public/cpp/ukm_recorder.h

@@ -95,6 +95,11 @@ class METRICS_EXPORT UkmRecorder {
   // Disables sampling for testing purposes.
   virtual void DisableSamplingForTesting(){};
 
+ protected:
+  // Type-safe wrappers for Update<X> functions.
+  void RecordOtherURL(base::UkmSourceId source_id, const GURL& url);
+  void RecordAppURL(base::UkmSourceId source_id, const GURL& url);
+
  private:
   friend DelegatingUkmRecorder;
   friend IOSChromePasswordManagerClient;

services/metrics/public/cpp/ukm_source_id.cc

@@ -10,39 +10,16 @@
 
 namespace ukm {
 
-namespace {
-
-const int64_t kLowBitsMask = (INT64_C(1) << 32) - 1;
-const int64_t kNumTypeBits = 2;
-const int64_t kTypeMask = (INT64_C(1) << kNumTypeBits) - 1;
-
-}  // namespace
-
 SourceId AssignNewSourceId() {
-  // Generate some bits which are unique to this process, so we can generate
-  // IDs independently in different processes. IDs generated by this method may
-  // collide, but it should be sufficiently rare enough to not impact data
-  // quality.
-  const static int64_t process_id_bits =
-      static_cast<int64_t>(base::RandUint64()) & ~kLowBitsMask;
-  // Generate some bits which are unique within the process, using a counter.
-  static base::AtomicSequenceNumber seq;
-  SourceId local_id = ConvertToSourceId(seq.GetNext() + 1, SourceIdType::UKM);
-  // Combine the local and process bits to generate a unique ID.
-  return (local_id & kLowBitsMask) | process_id_bits;
+  return base::UkmSourceId::New().ToInt64();
 }
 
 SourceId ConvertToSourceId(int64_t other_id, SourceIdType id_type) {
-  const int64_t type_bits = static_cast<int64_t>(id_type);
-  DCHECK_EQ(type_bits, type_bits & kTypeMask);
-  // Stores the the type ID in the low bits of the source id, and shift the rest
-  // of the ID to make room.  This could cause the original ID to overflow, but
-  // that should be rare enough that it won't matter for UKM's purposes.
-  return (other_id << kNumTypeBits) | type_bits;
+  return base::UkmSourceId::FromOtherId(other_id, id_type).ToInt64();
 }
 
 SourceIdType GetSourceIdType(SourceId source_id) {
-  return static_cast<SourceIdType>(source_id & kTypeMask);
+  return base::UkmSourceId::FromInt64(source_id).GetType();
 }
 
 }  // namespace ukm

services/metrics/public/cpp/ukm_source_id.h

@@ -7,17 +7,14 @@
 
 #include <stdint.h>
 
+#include "base/metrics/ukm_source_id.h"
 #include "services/metrics/public/cpp/metrics_export.h"
 
 namespace ukm {
 
 typedef int64_t SourceId;
 
-enum class SourceIdType : int64_t {
-  UKM = 0,
-  NAVIGATION_ID = 1,
-  APP_ID = 2,
-};
+using SourceIdType = base::UkmSourceId::Type;
 
 const SourceId kInvalidSourceId = 0;
 

tools/metrics/ukm/builders_template.py

@@ -32,7 +32,8 @@ namespace builders {{
 event_template="""
 class {event.name} final : public ::ukm::internal::UkmEntryBuilderBase {{
  public:
-  {event.name}(ukm::SourceId source_id);
+  explicit {event.name}(ukm::SourceId source_id);
+  explicit {event.name}(base::UkmSourceId source_id);
   ~{event.name}() override;
 
   static const char kEntryName[];
@@ -70,6 +71,10 @@ const char {event.name}::kEntryName[] = "{event.raw_name}";
   ::ukm::internal::UkmEntryBuilderBase(source_id, kEntryNameHash) {{
 }}
 
+{event.name}::{event.name}(base::UkmSourceId source_id) :
+  ::ukm::internal::UkmEntryBuilderBase(source_id, kEntryNameHash) {{
+}}
+
 {event.name}::~{event.name}() = default;
 
 {metric_code}