Convert uses of `const char*` to `std::string` (#1567)

* Convert uses of const char* to std::string

* fix sanitizer builds

* reformat user guide

* include python bindings

* clang-format

bindings/python/google_benchmark/benchmark.cc

@@ -34,7 +34,7 @@ std::vector<std::string> Initialize(const std::vector<std::string>& argv) {
   return remaining_argv;
 }
 
-benchmark::internal::Benchmark* RegisterBenchmark(const char* name,
+benchmark::internal::Benchmark* RegisterBenchmark(const std::string& name,
                                                   nb::callable f) {
   return benchmark::RegisterBenchmark(
       name, [f](benchmark::State& state) { f(&state); });
@@ -165,8 +165,8 @@ NB_MODULE(_benchmark, m) {
       .def_prop_rw("complexity_n", &State::complexity_length_n,
                     &State::SetComplexityN)
       .def_prop_rw("items_processed", &State::items_processed,
-                    &State::SetItemsProcessed)
-      .def("set_label", (void (State::*)(const char*)) & State::SetLabel)
+                   &State::SetItemsProcessed)
+      .def("set_label", &State::SetLabel)
       .def("range", &State::range, nb::arg("pos") = 0)
       .def_prop_ro("iterations", &State::iterations)
       .def_prop_ro("name", &State::name)

docs/user_guide.md

@@ -56,7 +56,7 @@
 
 [Exiting with an Error](#exiting-with-an-error)
 
-[A Faster KeepRunning Loop](#a-faster-keep-running-loop)
+[A Faster `KeepRunning` Loop](#a-faster-keep-running-loop)
 
 ## Benchmarking Tips
 
@@ -271,10 +271,12 @@ information about the machine on which the benchmarks are run.
 Global setup/teardown specific to each benchmark can be done by
 passing a callback to Setup/Teardown:
 
-The setup/teardown callbacks will be invoked once for each benchmark.
-If the benchmark is multi-threaded (will run in k threads), they will be invoked exactly once before
-each run with k threads.
-If the benchmark uses different size groups of threads, the above will be true for each size group.
+The setup/teardown callbacks will be invoked once for each benchmark. If the
+benchmark is multi-threaded (will run in k threads), they will be invoked
+exactly once before each run with k threads.
+
+If the benchmark uses different size groups of threads, the above will be true
+for each size group.
 
 Eg.,
 
@@ -1142,7 +1144,7 @@ int main(int argc, char** argv) {
 
 When errors caused by external influences, such as file I/O and network
 communication, occur within a benchmark the
-`State::SkipWithError(const char* msg)` function can be used to skip that run
+`State::SkipWithError(const std::string& msg)` function can be used to skip that run
 of benchmark and report the error. Note that only future iterations of the
 `KeepRunning()` are skipped. For the ranged-for version of the benchmark loop
 Users must explicitly exit the loop, otherwise all iterations will be performed.
@@ -1253,7 +1255,8 @@ the benchmark loop should be preferred.
 If you see this error:
 
 ```
-***WARNING*** CPU scaling is enabled, the benchmark real time measurements may be noisy and will incur extra overhead.
+***WARNING*** CPU scaling is enabled, the benchmark real time measurements may
+be noisy and will incur extra overhead.
 ```
 
 you might want to disable the CPU frequency scaling while running the

include/benchmark/benchmark.h

@@ -865,11 +865,7 @@ class BENCHMARK_EXPORT State {
   //  BM_Compress   50         50   14115038  compress:27.3%
   //
   // REQUIRES: a benchmark has exited its benchmarking loop.
-  void SetLabel(const char* label);
-
-  void BENCHMARK_ALWAYS_INLINE SetLabel(const std::string& str) {
-    this->SetLabel(str.c_str());
-  }
+  void SetLabel(const std::string& label);
 
   // Range arguments for this run. CHECKs if the argument has been set.
   BENCHMARK_ALWAYS_INLINE
@@ -1249,8 +1245,8 @@ class BENCHMARK_EXPORT Benchmark {
   TimeUnit GetTimeUnit() const;
 
  protected:
-  explicit Benchmark(const char* name);
-  void SetName(const char* name);
+  explicit Benchmark(const std::string& name);
+  void SetName(const std::string& name);
 
  public:
   const char* GetName() const;
@@ -1305,12 +1301,12 @@ class BENCHMARK_EXPORT Benchmark {
 // the specified functor 'fn'.
 //
 // RETURNS: A pointer to the registered benchmark.
-internal::Benchmark* RegisterBenchmark(const char* name,
+internal::Benchmark* RegisterBenchmark(const std::string& name,
                                        internal::Function* fn);
 
 #if defined(BENCHMARK_HAS_CXX11)
 template <class Lambda>
-internal::Benchmark* RegisterBenchmark(const char* name, Lambda&& fn);
+internal::Benchmark* RegisterBenchmark(const std::string& name, Lambda&& fn);
 #endif
 
 // Remove all registered benchmarks. All pointers to previously registered
@@ -1322,7 +1318,7 @@ namespace internal {
 // (ie those created using the BENCHMARK(...) macros.
 class BENCHMARK_EXPORT FunctionBenchmark : public Benchmark {
  public:
-  FunctionBenchmark(const char* name, Function* func)
+  FunctionBenchmark(const std::string& name, Function* func)
       : Benchmark(name), func_(func) {}
 
   void Run(State& st) BENCHMARK_OVERRIDE;
@@ -1339,20 +1335,20 @@ class LambdaBenchmark : public Benchmark {
 
  private:
   template <class OLambda>
-  LambdaBenchmark(const char* name, OLambda&& lam)
+  LambdaBenchmark(const std::string& name, OLambda&& lam)
       : Benchmark(name), lambda_(std::forward<OLambda>(lam)) {}
 
   LambdaBenchmark(LambdaBenchmark const&) = delete;
 
   template <class Lam>  // NOLINTNEXTLINE(readability-redundant-declaration)
-  friend Benchmark* ::benchmark::RegisterBenchmark(const char*, Lam&&);
+  friend Benchmark* ::benchmark::RegisterBenchmark(const std::string&, Lam&&);
 
   Lambda lambda_;
 };
 #endif
 }  // namespace internal
 
-inline internal::Benchmark* RegisterBenchmark(const char* name,
+inline internal::Benchmark* RegisterBenchmark(const std::string& name,
                                               internal::Function* fn) {
   return internal::RegisterBenchmarkInternal(
       ::new internal::FunctionBenchmark(name, fn));
@@ -1360,7 +1356,7 @@ inline internal::Benchmark* RegisterBenchmark(const char* name,
 
 #ifdef BENCHMARK_HAS_CXX11
 template <class Lambda>
-internal::Benchmark* RegisterBenchmark(const char* name, Lambda&& fn) {
+internal::Benchmark* RegisterBenchmark(const std::string& name, Lambda&& fn) {
   using BenchType =
       internal::LambdaBenchmark<typename std::decay<Lambda>::type>;
   return internal::RegisterBenchmarkInternal(
@@ -1371,7 +1367,7 @@ internal::Benchmark* RegisterBenchmark(const char* name, Lambda&& fn) {
 #if defined(BENCHMARK_HAS_CXX11) && \
     (!defined(BENCHMARK_GCC_VERSION) || BENCHMARK_GCC_VERSION >= 409)
 template <class Lambda, class... Args>
-internal::Benchmark* RegisterBenchmark(const char* name, Lambda&& fn,
+internal::Benchmark* RegisterBenchmark(const std::string& name, Lambda&& fn,
                                        Args&&... args) {
   return benchmark::RegisterBenchmark(
       name, [=](benchmark::State& st) { fn(st, args...); });

src/benchmark.cc

@@ -273,7 +273,7 @@ void State::SetIterationTime(double seconds) {
   timer_->SetIterationTime(seconds);
 }
 
-void State::SetLabel(const char* label) {
+void State::SetLabel(const std::string& label) {
   MutexLock l(manager_->GetBenchmarkMutex());
   manager_->results.report_label_ = label;
 }

src/benchmark_register.cc

@@ -204,7 +204,7 @@ bool FindBenchmarksInternal(const std::string& re,
 //                               Benchmark
 //=============================================================================//
 
-Benchmark::Benchmark(const char* name)
+Benchmark::Benchmark(const std::string& name)
     : name_(name),
       aggregation_report_mode_(ARM_Unspecified),
       time_unit_(GetDefaultTimeUnit()),
@@ -230,7 +230,7 @@ Benchmark::Benchmark(const char* name)
 Benchmark::~Benchmark() {}
 
 Benchmark* Benchmark::Name(const std::string& name) {
-  SetName(name.c_str());
+  SetName(name);
   return this;
 }
 
@@ -468,7 +468,7 @@ Benchmark* Benchmark::ThreadPerCpu() {
   return this;
 }
 
-void Benchmark::SetName(const char* name) { name_ = name; }
+void Benchmark::SetName(const std::string& name) { name_ = name; }
 
 const char* Benchmark::GetName() const { return name_.c_str(); }
 

src/benchmark_runner.cc

@@ -177,11 +177,10 @@ BenchTimeType ParseBenchMinTime(const std::string& value) {
   }
 
   if (value.back() == 'x') {
-    const char* iters_str = value.c_str();
     char* p_end;
     // Reset errno before it's changed by strtol.
     errno = 0;
-    IterationCount num_iters = std::strtol(iters_str, &p_end, 10);
+    IterationCount num_iters = std::strtol(value.c_str(), &p_end, 10);
 
     // After a valid parse, p_end should have been set to
     // point to the 'x' suffix.
@@ -194,7 +193,6 @@ BenchTimeType ParseBenchMinTime(const std::string& value) {
     return ret;
   }
 
-  const char* time_str = value.c_str();
   bool has_suffix = value.back() == 's';
   if (!has_suffix) {
     BM_VLOG(0) << "Value passed to --benchmark_min_time should have a suffix. "
@@ -204,7 +202,7 @@ BenchTimeType ParseBenchMinTime(const std::string& value) {
   char* p_end;
   // Reset errno before it's changed by strtod.
   errno = 0;
-  double min_time = std::strtod(time_str, &p_end);
+  double min_time = std::strtod(value.c_str(), &p_end);
 
   // After a successful parse, p_end should point to the suffix 's',
   // or the end of the string if the suffix was omitted.

src/json_reporter.cc

@@ -297,7 +297,8 @@ void JSONReporter::PrintRunData(Run const& run) {
     out << ",\n"
         << indent << FormatKV("max_bytes_used", memory_result.max_bytes_used);
 
-    auto report_if_present = [&out, &indent](const char* label, int64_t val) {
+    auto report_if_present = [&out, &indent](const std::string& label,
+                                             int64_t val) {
       if (val != MemoryManager::TombstoneValue)
         out << ",\n" << indent << FormatKV(label, val);
     };

test/output_test.h

@@ -85,7 +85,7 @@ std::string GetFileReporterOutput(int argc, char* argv[]);
 struct Results;
 typedef std::function<void(Results const&)> ResultsCheckFn;
 
-size_t AddChecker(const char* bm_name_pattern, const ResultsCheckFn& fn);
+size_t AddChecker(const std::string& bm_name_pattern, const ResultsCheckFn& fn);
 
 // Class holding the results of a benchmark.
 // It is passed in calls to checker functions.
@@ -117,7 +117,7 @@ struct Results {
 
   // get the string for a result by name, or nullptr if the name
   // is not found
-  const std::string* Get(const char* entry_name) const {
+  const std::string* Get(const std::string& entry_name) const {
     auto it = values.find(entry_name);
     if (it == values.end()) return nullptr;
     return &it->second;
@@ -126,12 +126,12 @@ struct Results {
   // get a result by name, parsed as a specific type.
   // NOTE: for counters, use GetCounterAs instead.
   template <class T>
-  T GetAs(const char* entry_name) const;
+  T GetAs(const std::string& entry_name) const;
 
   // counters are written as doubles, so they have to be read first
   // as a double, and only then converted to the asked type.
   template <class T>
-  T GetCounterAs(const char* entry_name) const {
+  T GetCounterAs(const std::string& entry_name) const {
     double dval = GetAs<double>(entry_name);
     T tval = static_cast<T>(dval);
     return tval;
@@ -139,7 +139,7 @@ struct Results {
 };
 
 template <class T>
-T Results::GetAs(const char* entry_name) const {
+T Results::GetAs(const std::string& entry_name) const {
   auto* sv = Get(entry_name);
   BM_CHECK(sv != nullptr && !sv->empty());
   std::stringstream ss;

test/output_test_helper.cc

@@ -299,7 +299,7 @@ std::vector<std::string> ResultsChecker::SplitCsv_(const std::string& line) {
 
 }  // end namespace internal
 
-size_t AddChecker(const char* bm_name, const ResultsCheckFn& fn) {
+size_t AddChecker(const std::string& bm_name, const ResultsCheckFn& fn) {
   auto& rc = internal::GetResultsChecker();
   rc.Add(bm_name, fn);
   return rc.results.size();
@@ -394,14 +394,14 @@ void RunOutputTests(int argc, char* argv[]) {
   benchmark::JSONReporter JR;
   benchmark::CSVReporter CSVR;
   struct ReporterTest {
-    const char* name;
+    std::string name;
     std::vector<TestCase>& output_cases;
     std::vector<TestCase>& error_cases;
     benchmark::BenchmarkReporter& reporter;
     std::stringstream out_stream;
     std::stringstream err_stream;
 
-    ReporterTest(const char* n, std::vector<TestCase>& out_tc,
+    ReporterTest(const std::string& n, std::vector<TestCase>& out_tc,
                  std::vector<TestCase>& err_tc,
                  benchmark::BenchmarkReporter& br)
         : name(n), output_cases(out_tc), error_cases(err_tc), reporter(br) {
@@ -409,12 +409,12 @@ void RunOutputTests(int argc, char* argv[]) {
       reporter.SetErrorStream(&err_stream);
     }
   } TestCases[] = {
-      {"ConsoleReporter", GetTestCaseList(TC_ConsoleOut),
+      {std::string("ConsoleReporter"), GetTestCaseList(TC_ConsoleOut),
        GetTestCaseList(TC_ConsoleErr), CR},
-      {"JSONReporter", GetTestCaseList(TC_JSONOut), GetTestCaseList(TC_JSONErr),
-       JR},
-      {"CSVReporter", GetTestCaseList(TC_CSVOut), GetTestCaseList(TC_CSVErr),
-       CSVR},
+      {std::string("JSONReporter"), GetTestCaseList(TC_JSONOut),
+       GetTestCaseList(TC_JSONErr), JR},
+      {std::string("CSVReporter"), GetTestCaseList(TC_CSVOut),
+       GetTestCaseList(TC_CSVErr), CSVR},
   };
 
   // Create the test reporter and run the benchmarks.
@@ -423,7 +423,8 @@ void RunOutputTests(int argc, char* argv[]) {
   benchmark::RunSpecifiedBenchmarks(&test_rep);
 
   for (auto& rep_test : TestCases) {
-    std::string msg = std::string("\nTesting ") + rep_test.name + " Output\n";
+    std::string msg =
+        std::string("\nTesting ") + rep_test.name + std::string(" Output\n");
     std::string banner(msg.size() - 1, '-');
     std::cout << banner << msg << banner << "\n";
 
@@ -440,7 +441,7 @@ void RunOutputTests(int argc, char* argv[]) {
   // the checks to subscribees.
   auto& csv = TestCases[2];
   // would use == but gcc spits a warning
-  BM_CHECK(std::strcmp(csv.name, "CSVReporter") == 0);
+  BM_CHECK(csv.name == std::string("CSVReporter"));
   internal::GetResultsChecker().CheckResults(csv.out_stream);
 }
 

test/register_benchmark_test.cc

@@ -19,11 +19,11 @@ class TestReporter : public benchmark::ConsoleReporter {
 };
 
 struct TestCase {
-  std::string name;
-  const char* label;
+  const std::string name;
+  const std::string label;
   // Note: not explicit as we rely on it being converted through ADD_CASES.
-  TestCase(const char* xname) : TestCase(xname, nullptr) {}
-  TestCase(const char* xname, const char* xlabel)
+  TestCase(const std::string& xname) : TestCase(xname, "") {}
+  TestCase(const std::string& xname, const std::string& xlabel)
       : name(xname), label(xlabel) {}
 
   typedef benchmark::BenchmarkReporter::Run Run;
@@ -32,7 +32,7 @@ struct TestCase {
     // clang-format off
     BM_CHECK(name == run.benchmark_name()) << "expected " << name << " got "
                                       << run.benchmark_name();
-    if (label) {
+    if (!label.empty()) {
       BM_CHECK(run.report_label == label) << "expected " << label << " got "
                                        << run.report_label;
     } else {
@@ -123,7 +123,7 @@ void TestRegistrationAtRuntime() {
   {
     CustomFixture fx;
     benchmark::RegisterBenchmark("custom_fixture", fx);
-    AddCases({"custom_fixture"});
+    AddCases({std::string("custom_fixture")});
   }
 #endif
 #ifndef BENCHMARK_HAS_NO_VARIADIC_REGISTER_BENCHMARK

test/skip_with_error_test.cc

@@ -48,7 +48,8 @@ struct TestCase {
 
 std::vector<TestCase> ExpectedResults;
 
-int AddCases(const char* base_name, std::initializer_list<TestCase> const& v) {
+int AddCases(const std::string& base_name,
+             std::initializer_list<TestCase> const& v) {
   for (auto TC : v) {
     TC.name = base_name + TC.name;
     ExpectedResults.push_back(std::move(TC));