1 // Copyright 2014 The Chromium Authors. All rights reserved.
2 // Use of this source code is governed by a BSD-style license that can be
3 // found in the LICENSE file.
5 #include "components/variations/experiment_labels.h"
9 #include "base/logging.h"
10 #include "base/strings/string_number_conversions.h"
11 #include "base/strings/string_split.h"
12 #include "base/strings/string_util.h"
13 #include "base/strings/utf_string_conversions.h"
14 #include "components/variations/variations_associated_data.h"
15 #include "components/variations/variations_experiment_util.h"
17 namespace variations
{
21 const char kVariationPrefix
[] = "CrVar";
23 // This method builds a single experiment label for a Chrome Variation,
24 // including a timestamp that is a year in the future from |current_time|. Since
25 // multiple headers can be transmitted, |count| is a number that is appended
26 // after the label key to differentiate the labels.
27 base::string16
CreateSingleExperimentLabel(int count
,
28 variations::VariationID id
,
29 const base::Time
& current_time
) {
30 // Build the parts separately so they can be validated.
31 const base::string16 key
=
32 base::ASCIIToUTF16(kVariationPrefix
) + base::IntToString16(count
);
33 DCHECK_LE(key
.size(), 8U);
34 const base::string16 value
= base::IntToString16(id
);
35 DCHECK_LE(value
.size(), 8U);
36 base::string16
label(key
);
37 label
+= base::ASCIIToUTF16("=");
39 label
+= base::ASCIIToUTF16("|");
40 label
+= variations::BuildExperimentDateString(current_time
);
46 base::string16
BuildGoogleUpdateExperimentLabel(
47 const base::FieldTrial::ActiveGroups
& active_groups
) {
48 base::string16 experiment_labels
;
51 const base::Time
current_time(base::Time::Now());
53 // Find all currently active VariationIDs associated with Google Update.
54 for (base::FieldTrial::ActiveGroups::const_iterator it
=
55 active_groups
.begin(); it
!= active_groups
.end(); ++it
) {
56 const variations::VariationID id
=
57 variations::GetGoogleVariationID(variations::GOOGLE_UPDATE_SERVICE
,
58 it
->trial_name
, it
->group_name
);
60 if (id
== variations::EMPTY_ID
)
63 if (!experiment_labels
.empty())
64 experiment_labels
+= variations::kExperimentLabelSeparator
;
65 experiment_labels
+= CreateSingleExperimentLabel(++counter
, id
,
69 return experiment_labels
;
72 base::string16
ExtractNonVariationLabels(const base::string16
& labels
) {
73 // First, split everything by the label separator.
74 std::vector
<base::StringPiece16
> entries
= base::SplitStringPiece(
75 labels
, base::StringPiece16(&variations::kExperimentLabelSeparator
, 1),
76 base::TRIM_WHITESPACE
, base::SPLIT_WANT_ALL
);
78 // For each label, keep the ones that do not look like a Variations label.
79 base::string16 non_variation_labels
;
80 for (const base::StringPiece16
& entry
: entries
) {
82 base::StartsWith(entry
,
83 base::ASCIIToUTF16(kVariationPrefix
),
84 base::CompareCase::INSENSITIVE_ASCII
)) {
88 // Dump the whole thing, including the timestamp.
89 if (!non_variation_labels
.empty())
90 non_variation_labels
+= variations::kExperimentLabelSeparator
;
91 entry
.AppendToString(&non_variation_labels
);
94 return non_variation_labels
;
97 base::string16
CombineExperimentLabels(const base::string16
& variation_labels
,
98 const base::string16
& other_labels
) {
99 base::StringPiece16
separator(&variations::kExperimentLabelSeparator
, 1);
100 DCHECK(!base::StartsWith(variation_labels
, separator
,
101 base::CompareCase::SENSITIVE
));
102 DCHECK(!base::EndsWith(variation_labels
, separator
,
103 base::CompareCase::SENSITIVE
));
104 DCHECK(!base::StartsWith(other_labels
, separator
,
105 base::CompareCase::SENSITIVE
));
106 DCHECK(!base::EndsWith(other_labels
, separator
,
107 base::CompareCase::SENSITIVE
));
108 // Note that if either label is empty, a separator is not necessary.
109 base::string16 combined_labels
= other_labels
;
110 if (!other_labels
.empty() && !variation_labels
.empty())
111 combined_labels
+= variations::kExperimentLabelSeparator
;
112 combined_labels
+= variation_labels
;
113 return combined_labels
;
116 } // namespace variations