Modernize Descriptor runtimeInit()

`std::string_view` is now available.

Author: aalkin

DataFormats/Headers/include/Headers/DataHeader.h

@@ -38,7 +38,6 @@
 #include <cstring> //needed for memcmp
 #include <string>
 #include <stdexcept>
-#include <climits>
 #include <limits>
 #include <cerrno>
 
@@ -258,30 +257,33 @@ struct Descriptor {
   ///
   /// Note: no assignment operator operator=(const char*) as this potentially runs
   /// into trouble with this general pointer type.
-  void runtimeInit(const char* string, short length = -1)
+  void runtimeInit(std::string_view string)
   {
-    char* target = str;
-    char* targetEnd = target;
-    if (length >= 0 && length < (int)N) {
-      targetEnd += length;
-    } else {
-      targetEnd += N;
-    }
-    const char* source = string;
-    for (; source != nullptr && target < targetEnd && *source != 0; ++target, ++source) {
-      *target = *source;
+    // empty strings and string longet than the descriptor size are not allowed
+    if (!string.empty() && (string.size() > (int)N)) {
+      throw std::invalid_argument("argument must not be longer than the descriptor size");
     }
-    targetEnd = str + N;
-    for (; target < targetEnd; ++target) {
-      *target = 0;
-    }
-    // require the string to be not longer than the descriptor size
-    if (source != nullptr && (*source == 0 || (length >= 0 && length <= (int)N))) {
-    } else {
-      throw std::invalid_argument("argument must not be longer than descriptor size");
+    // copy the content directly
+    std::memcpy(str, string.data(), string.size());
+    // nullify the remainder
+    auto* ptr = str + string.size();
+    for (; ptr < str + N; ++ptr) {
+      *ptr = 0;
     }
   }
 
+  /// compatibility version for null-terminated strings
+  void runtimeInit(const char* string)
+  {
+    runtimeInit(std::string_view{string, std::strlen(string)});
+  }
+
+  /// compatibility version for explicit length
+  void runtimeInit(const char* buffer, size_t length)
+  {
+    runtimeInit(std::string_view{buffer, length});
+  }
+
   bool operator==(const Descriptor& other) const { return std::memcmp(this->str, other.str, N) == 0; }
   bool operator<(const Descriptor& other) const { return std::memcmp(this->str, other.str, N) < 0; }
   bool operator!=(const Descriptor& other) const { return not this->operator==(other); }
@@ -298,7 +300,8 @@ struct Descriptor {
 
   /// get the descriptor as std::string
   template <typename T>
-  std::enable_if_t<std::is_same<T, std::string>::value == true, T> as() const
+    requires(std::same_as<T, std::string>)
+  T as() const
   {
     // backward search to find first non-zero char
     // FIXME: can optimize this by using the int value to start at e.g. size/2

DataFormats/Headers/test/testDataHeader.cxx

@@ -97,7 +97,7 @@ BOOST_AUTO_TEST_CASE(Descriptor_test)
   // check with runtime string
   std::string runtimeString = "RUNTIMES";
   TestDescriptorT runtimeDescriptor;
-  runtimeDescriptor.runtimeInit(runtimeString.c_str());
+  runtimeDescriptor.runtimeInit(runtimeString);
   BOOST_CHECK(runtimeDescriptor == TestDescriptorT("RUNTIMES"));
 
   BOOST_CHECK(testDescriptor.as<std::string>().length() == 8);
@@ -130,7 +130,7 @@ BOOST_AUTO_TEST_CASE(DataDescription_test)
 
   std::string runtimeString = "DATA_DESCRIPTION";
   DataDescription runtimeDesc;
-  runtimeDesc.runtimeInit(runtimeString.c_str());
+  runtimeDesc.runtimeInit(runtimeString);
   BOOST_CHECK(runtimeDesc == DataDescription("DATA_DESCRIPTION"));
 
   BOOST_CHECK(desc.as<std::string>().length() == 6);

Detectors/DCS/testWorkflow/src/DCSDataReplaySpec.cxx

@@ -153,7 +153,7 @@ o2::framework::DataProcessorSpec getDCSDataReplaySpec(std::vector<o2::dcs::test:
 
   o2::header::DataDescription dd;
 
-  dd.runtimeInit(desc.c_str(), desc.size());
+  dd.runtimeInit(desc);
 
   return DataProcessorSpec{
     "dcs-random-data-generator",

Detectors/DCS/testWorkflow/src/DCSRandomDataGeneratorSpec.cxx

@@ -168,7 +168,7 @@ o2::framework::DataProcessorSpec getDCSRandomDataGeneratorSpec(std::vector<o2::d
 
   o2::header::DataDescription dd;
 
-  dd.runtimeInit(desc.c_str(), desc.size());
+  dd.runtimeInit(desc);
 
   return DataProcessorSpec{
     "dcs-random-data-generator",

Detectors/DCS/testWorkflow/src/dcs-proxy.cxx

@@ -94,7 +94,7 @@ WorkflowSpec defineDataProcessing(ConfigContext const& config)
         std::unordered_map<DPID, std::string>* dpid2Det = mgr.getForTimeStamp<std::unordered_map<DPID, std::string>>(detStr + "/Config/DCSDPconfig", ts);
         for (auto& el : *dpid2Det) {
           o2::header::DataDescription tmpd;
-          tmpd.runtimeInit(el.second.c_str(), el.second.size());
+          tmpd.runtimeInit(el.second);
           dpid2DataDesc[el.first].push_back(tmpd);
         }
       }

Detectors/GlobalTrackingWorkflow/readers/src/irframe-reader-workflow.cxx

@@ -39,7 +39,7 @@ WorkflowSpec defineDataProcessing(ConfigContext const& cc)
   WorkflowSpec specs;
   o2::conf::ConfigurableParam::updateFromString(cc.options().get<std::string>("configKeyValues"));
   o2::header::DataOrigin origin;
-  origin.runtimeInit(cc.options().get<std::string>("data-origin").c_str());
+  origin.runtimeInit(cc.options().get<std::string>("data-origin"));
 
   specs.emplace_back(o2::globaltracking::getIRFrameReaderSpec(origin, (uint32_t)cc.options().get<int>("subspec"),
                                                               cc.options().get<std::string>("device-name"), cc.options().get<std::string>("file-name")));

Detectors/ITSMFT/ITS/workflow/src/DCSGeneratorSpec.cxx

@@ -131,7 +131,7 @@ o2::framework::DataProcessorSpec getITSDCSDataGeneratorSpec(const char* detName)
 
   o2::header::DataDescription dd;
 
-  dd.runtimeInit(desc.c_str(), desc.size());
+  dd.runtimeInit(desc);
 
   return DataProcessorSpec{
     "its-dcs-data-generator",

Detectors/ITSMFT/common/workflow/src/STFDecoderSpec.cxx

@@ -71,8 +71,8 @@ void STFDecoder<Mapping>::init(InitContext& ic)
     auto v2 = o2::utils::Str::tokenize(v1[1], '?');
     header::DataOrigin dataOrig;
     header::DataDescription dataDesc;
-    dataOrig.runtimeInit(v1[0].c_str());
-    dataDesc.runtimeInit(v2[0].c_str());
+    dataOrig.runtimeInit(v1[0]);
+    dataDesc.runtimeInit(v2[0]);
     Mapping map;
     for (int iLayer{0}; iLayer < mLayers; ++iLayer) {
       auto& dec = mDecoder.emplace_back(std::make_unique<RawPixelDecoder<Mapping>>());

Detectors/TOF/workflow/src/CompressedDecodingTask.cxx

@@ -458,7 +458,7 @@ DataProcessorSpec getCompressedDecodingSpec(const std::string& inputDesc, bool c
 
   //  inputs.emplace_back(std::string("x:TOF/" + inputDesc).c_str(), 0, Lifetime::Optional);
   o2::header::DataDescription dataDesc;
-  dataDesc.runtimeInit(inputDesc.c_str());
+  dataDesc.runtimeInit(inputDesc);
   inputs.emplace_back("x", ConcreteDataTypeMatcher{o2::header::gDataOriginTOF, dataDesc}, Lifetime::Timeframe);
   std::vector<OutputSpec> outputs;
   outputs.emplace_back(o2::header::gDataOriginTOF, "DIGITHEADER", 0, Lifetime::Timeframe);

Detectors/TPC/workflow/include/TPCWorkflow/TPCDistributeCMVSpec.h

@@ -229,7 +229,7 @@ class TPCDistributeCMVSpec : public o2::framework::Task
   {
     const std::string name = fmt::format("CMVAGG{}", lane);
     header::DataDescription description;
-    description.runtimeInit(name.substr(0, 16).c_str());
+    description.runtimeInit(name);
     return description;
   }
 
@@ -238,7 +238,7 @@ class TPCDistributeCMVSpec : public o2::framework::Task
   {
     const std::string name = fmt::format("CMVORB{}", lane);
     header::DataDescription description;
-    description.runtimeInit(name.substr(0, 16).c_str());
+    description.runtimeInit(name);
     return description;
   }