1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
|
// Copyright 2020 The Chromium Authors
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
#include "third_party/blink/renderer/modules/canvas/canvas2d/identifiability_study_helper.h"
#include <cstdint>
#include <initializer_list>
#include "base/containers/span.h"
#include "base/hash/legacy_hash.h"
#include "third_party/blink/public/common/privacy_budget/identifiable_token.h"
#include "third_party/blink/renderer/platform/heap/visitor.h"
namespace blink {
// The maximum number of canvas context operations to incorportate into digest
// computation -- constant, but may be overridden by tests using
// IdentifiabilityStudyHelper::ScopedMaxOperationsSetter.
/*static*/ int IdentifiabilityStudyHelper::max_operations_ = 1 << 20;
void IdentifiabilityStudyHelper::Trace(Visitor* visitor) const {
visitor->Trace(execution_context_);
}
void IdentifiabilityStudyHelper::AddTokens(
std::initializer_list<IdentifiableToken> tokens) {
for (IdentifiableToken token : tokens) {
partial_[position_++] = token.ToUkmMetricValue();
if (position_ == 8) {
chaining_value_ = DigestPartialData();
position_ = 0;
}
}
}
uint64_t IdentifiabilityStudyHelper::DigestPartialData() const {
return base::legacy::CityHash64WithSeed(
base::as_bytes(base::span(partial_).first(position_)), chaining_value_);
}
} // namespace blink
|
