Adopt absl::string_view in field trial test helpers

Bug: webrtc:13579
Change-Id: Ie16b2f1cf5288cf795ea6d40f4b3a37f76f00f76
Reviewed-on: https://webrtc-review.googlesource.com/c/src/+/258422
Reviewed-by: Artem Titov <titovartem@webrtc.org>
Commit-Queue: Danil Chapovalov <danilchap@webrtc.org>
Cr-Commit-Position: refs/heads/main@{#36505}

test/BUILD.gn

@@ -222,6 +222,7 @@ rtc_library("field_trial") {
     "field_trial.h",
   ]
 
+  absl_deps = [ "//third_party/abseil-cpp/absl/strings" ]
   deps = [
     "../rtc_base:checks",
     "../system_wrappers:field_trial",

test/explicit_key_value_config.cc

@@ -10,13 +10,14 @@
 
 #include "test/explicit_key_value_config.h"
 
+#include "absl/strings/string_view.h"
 #include "api/field_trials_view.h"
 #include "rtc_base/checks.h"
 
 namespace webrtc {
 namespace test {
 
-ExplicitKeyValueConfig::ExplicitKeyValueConfig(const std::string& s) {
+ExplicitKeyValueConfig::ExplicitKeyValueConfig(absl::string_view s) {
   std::string::size_type field_start = 0;
   while (field_start < s.size()) {
     std::string::size_type separator_pos = s.find('/', field_start);
@@ -24,7 +25,7 @@ ExplicitKeyValueConfig::ExplicitKeyValueConfig(const std::string& s) {
         << "Missing separator '/' after field trial key.";
     RTC_CHECK_GT(separator_pos, field_start)
         << "Field trial key cannot be empty.";
-    std::string key = s.substr(field_start, separator_pos - field_start);
+    std::string key(s.substr(field_start, separator_pos - field_start));
     field_start = separator_pos + 1;
 
     RTC_CHECK_LT(field_start, s.size())
@@ -34,7 +35,7 @@ ExplicitKeyValueConfig::ExplicitKeyValueConfig(const std::string& s) {
         << "Missing terminating '/' in field trial string.";
     RTC_CHECK_GT(separator_pos, field_start)
         << "Field trial value cannot be empty.";
-    std::string value = s.substr(field_start, separator_pos - field_start);
+    std::string value(s.substr(field_start, separator_pos - field_start));
     field_start = separator_pos + 1;
 
     key_value_map_[key] = value;
@@ -46,7 +47,7 @@ ExplicitKeyValueConfig::ExplicitKeyValueConfig(const std::string& s) {
 }
 
 std::string ExplicitKeyValueConfig::Lookup(absl::string_view key) const {
-  auto it = key_value_map_.find(std::string(key));
+  auto it = key_value_map_.find(key);
   if (it != key_value_map_.end())
     return it->second;
   return "";

test/explicit_key_value_config.h

@@ -11,6 +11,7 @@
 #ifndef TEST_EXPLICIT_KEY_VALUE_CONFIG_H_
 #define TEST_EXPLICIT_KEY_VALUE_CONFIG_H_
 
+#include <functional>
 #include <map>
 #include <string>
 
@@ -22,11 +23,13 @@ namespace test {
 
 class ExplicitKeyValueConfig : public FieldTrialsView {
  public:
-  explicit ExplicitKeyValueConfig(const std::string& s);
+  explicit ExplicitKeyValueConfig(absl::string_view s);
   std::string Lookup(absl::string_view key) const override;
 
  private:
-  std::map<std::string, std::string> key_value_map_;
+  // Unlike std::less<std::string>, std::less<> is transparent and allows
+  // heterogeneous lookup directly with absl::string_view.
+  std::map<std::string, std::string, std::less<>> key_value_map_;
 };
 
 }  // namespace test

test/field_trial.cc

@@ -10,23 +10,21 @@
 
 #include "test/field_trial.h"
 
-#include <algorithm>
-#include <cstdio>
-#include <cstdlib>
-#include <map>
 #include <string>
 
+#include "absl/strings/string_view.h"
 #include "rtc_base/checks.h"
 #include "system_wrappers/include/field_trial.h"
 
 namespace webrtc {
 namespace test {
 
-ScopedFieldTrials::ScopedFieldTrials(const std::string& config)
+ScopedFieldTrials::ScopedFieldTrials(absl::string_view config)
-    : previous_field_trials_(webrtc::field_trial::GetFieldTrialString()) {
+    : current_field_trials_(config),
-  RTC_CHECK(webrtc::field_trial::FieldTrialsStringIsValid(config.c_str()))
+      previous_field_trials_(webrtc::field_trial::GetFieldTrialString()) {
-      << "Invalid field trials string: " << config;
+  RTC_CHECK(webrtc::field_trial::FieldTrialsStringIsValid(
-  current_field_trials_ = config;
+      current_field_trials_.c_str()))
+      << "Invalid field trials string: " << current_field_trials_;
   webrtc::field_trial::InitFieldTrialsFromString(current_field_trials_.c_str());
 }
 

test/field_trial.h

@@ -11,9 +11,10 @@
 #ifndef TEST_FIELD_TRIAL_H_
 #define TEST_FIELD_TRIAL_H_
 
-#include <map>
 #include <string>
 
+#include "absl/strings/string_view.h"
+
 namespace webrtc {
 namespace test {
 
@@ -21,7 +22,7 @@ namespace test {
 // After this class goes out of scope previous field trials will be restored.
 class ScopedFieldTrials {
  public:
-  explicit ScopedFieldTrials(const std::string& config);
+  explicit ScopedFieldTrials(absl::string_view config);
   ScopedFieldTrials(const ScopedFieldTrials&) = delete;
   ScopedFieldTrials& operator=(const ScopedFieldTrials&) = delete;
   ~ScopedFieldTrials();

test/scoped_key_value_config.cc

@@ -18,8 +18,9 @@
 namespace {
 
 // This part is copied from system_wrappers/field_trial.cc.
-void InsertIntoMap(std::map<std::string, std::string>& key_value_map,
+void InsertIntoMap(
-                   const std::string& s) {
+    std::map<std::string, std::string, std::less<>>& key_value_map,
+    absl::string_view s) {
   std::string::size_type field_start = 0;
   while (field_start < s.size()) {
     std::string::size_type separator_pos = s.find('/', field_start);
@@ -27,7 +28,7 @@ void InsertIntoMap(std::map<std::string, std::string>& key_value_map,
         << "Missing separator '/' after field trial key.";
     RTC_CHECK_GT(separator_pos, field_start)
         << "Field trial key cannot be empty.";
-    std::string key = s.substr(field_start, separator_pos - field_start);
+    std::string key(s.substr(field_start, separator_pos - field_start));
     field_start = separator_pos + 1;
 
     RTC_CHECK_LT(field_start, s.size())
@@ -37,7 +38,7 @@ void InsertIntoMap(std::map<std::string, std::string>& key_value_map,
         << "Missing terminating '/' in field trial string.";
     RTC_CHECK_GT(separator_pos, field_start)
         << "Field trial value cannot be empty.";
-    std::string value = s.substr(field_start, separator_pos - field_start);
+    std::string value(s.substr(field_start, separator_pos - field_start));
     field_start = separator_pos + 1;
 
     key_value_map[key] = value;
@@ -56,15 +57,15 @@ namespace test {
 ScopedKeyValueConfig::ScopedKeyValueConfig()
     : ScopedKeyValueConfig(nullptr, "") {}
 
-ScopedKeyValueConfig::ScopedKeyValueConfig(const std::string& s)
+ScopedKeyValueConfig::ScopedKeyValueConfig(absl::string_view s)
     : ScopedKeyValueConfig(nullptr, s) {}
 
 ScopedKeyValueConfig::ScopedKeyValueConfig(ScopedKeyValueConfig& parent,
-                                           const std::string& s)
+                                           absl::string_view s)
     : ScopedKeyValueConfig(&parent, s) {}
 
 ScopedKeyValueConfig::ScopedKeyValueConfig(ScopedKeyValueConfig* parent,
-                                           const std::string& s)
+                                           absl::string_view s)
     : parent_(parent), leaf_(nullptr) {
   InsertIntoMap(key_value_map_, s);
 
@@ -105,7 +106,7 @@ std::string ScopedKeyValueConfig::Lookup(absl::string_view key) const {
 }
 
 std::string ScopedKeyValueConfig::LookupRecurse(absl::string_view key) const {
-  auto it = key_value_map_.find(std::string(key));
+  auto it = key_value_map_.find(key);
   if (it != key_value_map_.end())
     return it->second;
 

test/scoped_key_value_config.h

@@ -11,6 +11,7 @@
 #ifndef TEST_SCOPED_KEY_VALUE_CONFIG_H_
 #define TEST_SCOPED_KEY_VALUE_CONFIG_H_
 
+#include <functional>
 #include <map>
 #include <memory>
 #include <string>
@@ -26,13 +27,13 @@ class ScopedKeyValueConfig : public FieldTrialsView {
  public:
   virtual ~ScopedKeyValueConfig();
   ScopedKeyValueConfig();
-  explicit ScopedKeyValueConfig(const std::string& s);
+  explicit ScopedKeyValueConfig(absl::string_view s);
-  ScopedKeyValueConfig(ScopedKeyValueConfig& parent, const std::string& s);
+  ScopedKeyValueConfig(ScopedKeyValueConfig& parent, absl::string_view s);
 
   std::string Lookup(absl::string_view key) const override;
 
  private:
-  ScopedKeyValueConfig(ScopedKeyValueConfig* parent, const std::string& s);
+  ScopedKeyValueConfig(ScopedKeyValueConfig* parent, absl::string_view s);
   ScopedKeyValueConfig* GetRoot(ScopedKeyValueConfig* n);
   std::string LookupRecurse(absl::string_view key) const;
 
@@ -42,7 +43,9 @@ class ScopedKeyValueConfig : public FieldTrialsView {
   // Only set on root (e.g with parent_ == nullptr).
   const ScopedKeyValueConfig* leaf_;
 
-  std::map<std::string, std::string> key_value_map_;
+  // Unlike std::less<std::string>, std::less<> is transparent and allows
+  // heterogeneous lookup directly with absl::string_view.
+  std::map<std::string, std::string, std::less<>> key_value_map_;
   std::unique_ptr<ScopedFieldTrials> scoped_field_trials_;
 };