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// Copyright 2018 The Chromium Authors
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
#include "base/test/metrics/histogram_enum_reader.h"
#include <optional>
#include "base/files/file_path.h"
#include "base/files/file_util.h"
#include "base/path_service.h"
#include "base/strings/string_number_conversions.h"
#include "testing/gtest/include/gtest/gtest.h"
#include "third_party/libxml/chromium/xml_reader.h"
namespace base {
namespace {
// This is a helper function to the ReadEnumFromHistogramsXml().
// Extracts single enum (with integer values) from histograms.xml.
// Expects |reader| to point at given enum.
// Returns map { value => label } on success, and nullopt on failure.
std::optional<HistogramEnumEntryMap> ParseEnumFromHistogramsXml(
const std::string& enum_name,
XmlReader* reader) {
int entries_index = -1;
HistogramEnumEntryMap result;
bool success = true;
while (true) {
const std::string node_name = reader->NodeName();
if (node_name == "enum" && reader->IsClosingElement()) {
break;
}
if (node_name == "int") {
++entries_index;
std::string value_str;
std::string label;
const bool has_value = reader->NodeAttribute("value", &value_str);
const bool has_label = reader->NodeAttribute("label", &label);
if (!has_value) {
ADD_FAILURE() << "Bad " << enum_name << " enum entry (at index "
<< entries_index << ", label='" << label
<< "'): No 'value' attribute.";
success = false;
}
if (!has_label) {
ADD_FAILURE() << "Bad " << enum_name << " enum entry (at index "
<< entries_index << ", value_str='" << value_str
<< "'): No 'label' attribute.";
success = false;
}
HistogramBase::Sample32 value;
if (has_value && !StringToInt(value_str, &value)) {
ADD_FAILURE() << "Bad " << enum_name << " enum entry (at index "
<< entries_index << ", label='" << label
<< "', value_str='" << value_str
<< "'): 'value' attribute is not integer.";
success = false;
}
if (result.count(value)) {
ADD_FAILURE() << "Bad " << enum_name << " enum entry (at index "
<< entries_index << ", label='" << label
<< "', value_str='" << value_str
<< "'): duplicate value '" << value_str
<< "' found in enum. The previous one has label='"
<< result[value] << "'.";
success = false;
}
if (success) {
result[value] = label;
}
}
// All enum entries are on the same level, so it is enough to iterate
// until possible.
reader->Next();
}
if (success) {
return result;
}
return std::nullopt;
}
} // namespace
std::optional<HistogramEnumEntryMap> ReadEnumFromEnumsXml(
const std::string& enum_name,
const std::optional<std::string>& subdirectory) {
FilePath src_root;
if (!PathService::Get(DIR_SRC_TEST_DATA_ROOT, &src_root)) {
ADD_FAILURE() << "Failed to get src root.";
return std::nullopt;
}
base::FilePath enums_xml =
src_root.AppendASCII("tools").AppendASCII("metrics").AppendASCII(
"histograms");
if (subdirectory) {
enums_xml =
enums_xml.AppendASCII("metadata").AppendASCII(subdirectory.value());
}
enums_xml = enums_xml.AppendASCII("enums.xml");
if (!PathExists(enums_xml)) {
ADD_FAILURE() << "enums.xml file does not exist.";
return std::nullopt;
}
XmlReader enums_xml_reader;
if (!enums_xml_reader.LoadFile(enums_xml.MaybeAsASCII())) {
ADD_FAILURE() << "Failed to load enums.xml";
return std::nullopt;
}
std::optional<HistogramEnumEntryMap> result;
// Implement simple depth first search.
while (true) {
const std::string node_name = enums_xml_reader.NodeName();
if (node_name == "enum") {
std::string name;
if (enums_xml_reader.NodeAttribute("name", &name) && name == enum_name) {
if (result.has_value()) {
ADD_FAILURE() << "Duplicate enum '" << enum_name
<< "' found in enums.xml";
return std::nullopt;
}
const bool got_into_enum = enums_xml_reader.Read();
if (!got_into_enum) {
ADD_FAILURE() << "Bad enum '" << enum_name
<< "' (looks empty) found in enums.xml.";
return std::nullopt;
}
result = ParseEnumFromHistogramsXml(enum_name, &enums_xml_reader);
if (!result.has_value()) {
ADD_FAILURE() << "Bad enum '" << enum_name
<< "' found in histograms.xml (format error).";
return std::nullopt;
}
}
}
// Go deeper if possible (stops at the closing tag of the deepest node).
if (enums_xml_reader.Read()) {
continue;
}
// Try next node on the same level (skips closing tag).
if (enums_xml_reader.Next()) {
continue;
}
// Go up until next node on the same level exists.
while (enums_xml_reader.Depth() && !enums_xml_reader.SkipToElement()) {
}
// Reached top. histograms.xml consists of the single top level node
// 'histogram-configuration', so this is the end.
if (!enums_xml_reader.Depth()) {
break;
}
}
return result;
}
} // namespace base
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