From 3e37f60c2f8ac6840cf78bdd930cadefaedcf184 Mon Sep 17 00:00:00 2001
From: Giulio Eulisse <10544+ktf@users.noreply.github.com>
Date: Wed, 8 Jan 2025 14:18:39 +0100
Subject: [PATCH] DPL: reduce bloat in runDataProcessing.h

---
 .../include/Framework/runDataProcessing.h     | 70 +++++++------------
 1 file changed, 27 insertions(+), 43 deletions(-)

diff --git a/Framework/Core/include/Framework/runDataProcessing.h b/Framework/Core/include/Framework/runDataProcessing.h
index 8293bf0cf7039..6c1897bc8c1f3 100644
--- a/Framework/Core/include/Framework/runDataProcessing.h
+++ b/Framework/Core/include/Framework/runDataProcessing.h
@@ -11,6 +11,7 @@
 #ifndef FRAMEWORK_RUN_DATA_PROCESSING_H
 #define FRAMEWORK_RUN_DATA_PROCESSING_H
 
+#include <fmt/format.h>
 #include "Framework/ChannelConfigurationPolicy.h"
 #include "Framework/CallbacksPolicy.h"
 #include "Framework/CompletionPolicy.h"
@@ -30,6 +31,7 @@
 #include "Framework/CheckTypes.h"
 #include "Framework/StructToTuple.h"
 #include "Framework/ConfigParamDiscovery.h"
+#include "ResourcePolicy.h"
 #include "ServiceRegistryRef.h"
 #include <vector>
 
@@ -66,9 +68,7 @@ o2::framework::WorkflowSpec defineDataProcessing(o2::framework::ConfigContext co
 
 // By default we leave the channel policies unchanged. Notice that the default still include
 // a "match all" policy which uses pub / sub
-// FIXME: add a debug statement saying that the default policy was used?
 
-void defaultConfiguration(std::vector<o2::framework::ChannelConfigurationPolicy>& channelPolicies) {}
 void defaultConfiguration(std::vector<o2::framework::ConfigParamSpec>& globalWorkflowOptions)
 {
   o2::framework::call_if_defined<struct WorkflowOptions>([&](auto* ptr) {
@@ -80,9 +80,6 @@ void defaultConfiguration(std::vector<o2::framework::ConfigParamSpec>& globalWor
   });
 }
 
-void defaultConfiguration(std::vector<o2::framework::CompletionPolicy>& completionPolicies) {}
-void defaultConfiguration(std::vector<o2::framework::DispatchPolicy>& dispatchPolicies) {}
-void defaultConfiguration(std::vector<o2::framework::ResourcePolicy>& resourcePolicies) {}
 void defaultConfiguration(std::vector<o2::framework::ServiceSpec>& services)
 {
   if (services.empty()) {
@@ -90,9 +87,6 @@ void defaultConfiguration(std::vector<o2::framework::ServiceSpec>& services)
   }
 }
 
-void defaultConfiguration(std::vector<o2::framework::CallbacksPolicy>& callbacksPolicies) {}
-void defaultConfiguration(std::vector<o2::framework::SendingPolicy>& callbacksPolicies) {}
-
 /// Workflow options which are required by DPL in order to work.
 std::vector<o2::framework::ConfigParamSpec> requiredWorkflowOptions();
 
@@ -101,19 +95,26 @@ void defaultConfiguration(o2::framework::OnWorkflowTerminationHook& hook)
   hook = [](const char*) {};
 }
 
+template <typename T>
+concept WithUserOverride = requires(T& something) { customize(something); };
+
+template <typename T>
+concept WithNonTrivialDefault = !WithUserOverride<T> && requires(T& something) { defaultConfiguration(something); };
+
 struct UserCustomizationsHelper {
-  template <typename T>
-  static auto userDefinedCustomization(T& something, int preferUser) -> decltype(customize(something), void())
+  static auto userDefinedCustomization(WithUserOverride auto& something) -> void
   {
     customize(something);
   }
 
-  template <typename T>
-  static auto userDefinedCustomization(T& something, long preferUser)
-    -> decltype(defaultConfiguration(something), void())
+  static auto userDefinedCustomization(WithNonTrivialDefault auto& something) -> void
   {
     defaultConfiguration(something);
   }
+
+  static auto userDefinedCustomization(auto&) -> void
+  {
+  }
 };
 
 namespace o2::framework
@@ -144,12 +145,14 @@ int doMain(int argc, char** argv, o2::framework::WorkflowSpec const& specs,
 void doDefaultWorkflowTerminationHook();
 
 template <typename T>
+  requires requires(T& policy) { { T::createDefaultPolicies() } -> std::same_as<std::vector<T>>; }
 std::vector<T> injectCustomizations()
 {
   std::vector<T> policies;
-  UserCustomizationsHelper::userDefinedCustomization(policies, 0);
+  UserCustomizationsHelper::userDefinedCustomization(policies);
   auto defaultPolicies = T::createDefaultPolicies();
-  policies.insert(std::end(policies), std::begin(policies), std::end(policies));
+  policies.insert(std::end(policies), std::begin(defaultPolicies), std::end(defaultPolicies));
+  return policies;
 }
 
 int mainNoCatch(int argc, char** argv)
@@ -158,34 +161,15 @@ int mainNoCatch(int argc, char** argv)
   using namespace boost::program_options;
 
   std::vector<o2::framework::ConfigParamSpec> workflowOptions;
-  UserCustomizationsHelper::userDefinedCustomization(workflowOptions, 0);
+  UserCustomizationsHelper::userDefinedCustomization(workflowOptions);
   auto requiredWorkflowOptions = WorkflowCustomizationHelpers::requiredWorkflowOptions();
   workflowOptions.insert(std::end(workflowOptions), std::begin(requiredWorkflowOptions), std::end(requiredWorkflowOptions));
 
-  std::vector<CompletionPolicy> completionPolicies;
-  UserCustomizationsHelper::userDefinedCustomization(completionPolicies, 0);
-  auto defaultCompletionPolicies = CompletionPolicy::createDefaultPolicies();
-  completionPolicies.insert(std::end(completionPolicies), std::begin(defaultCompletionPolicies), std::end(defaultCompletionPolicies));
-
-  std::vector<DispatchPolicy> dispatchPolicies;
-  UserCustomizationsHelper::userDefinedCustomization(dispatchPolicies, 0);
-  auto defaultDispatchPolicies = DispatchPolicy::createDefaultPolicies();
-  dispatchPolicies.insert(std::end(dispatchPolicies), std::begin(defaultDispatchPolicies), std::end(defaultDispatchPolicies));
-
-  std::vector<ResourcePolicy> resourcePolicies;
-  UserCustomizationsHelper::userDefinedCustomization(resourcePolicies, 0);
-  auto defaultResourcePolicies = ResourcePolicy::createDefaultPolicies();
-  resourcePolicies.insert(std::end(resourcePolicies), std::begin(defaultResourcePolicies), std::end(defaultResourcePolicies));
-
-  std::vector<CallbacksPolicy> callbacksPolicies;
-  UserCustomizationsHelper::userDefinedCustomization(callbacksPolicies, 0);
-  auto defaultCallbacksPolicies = CallbacksPolicy::createDefaultPolicies();
-  callbacksPolicies.insert(std::end(callbacksPolicies), std::begin(defaultCallbacksPolicies), std::end(defaultCallbacksPolicies));
-
-  std::vector<SendingPolicy> sendingPolicies;
-  UserCustomizationsHelper::userDefinedCustomization(sendingPolicies, 0);
-  auto defaultSendingPolicies = SendingPolicy::createDefaultPolicies();
-  sendingPolicies.insert(std::end(sendingPolicies), std::begin(defaultSendingPolicies), std::end(defaultSendingPolicies));
+  std::vector<CompletionPolicy> completionPolicies = injectCustomizations<CompletionPolicy>();
+  std::vector<DispatchPolicy> dispatchPolicies = injectCustomizations<DispatchPolicy>();
+  std::vector<ResourcePolicy> resourcePolicies = injectCustomizations<ResourcePolicy>();
+  std::vector<CallbacksPolicy> callbacksPolicies = injectCustomizations<CallbacksPolicy>();
+  std::vector<SendingPolicy> sendingPolicies = injectCustomizations<SendingPolicy>();
 
   std::vector<std::unique_ptr<ParamRetriever>> retrievers;
   std::unique_ptr<ParamRetriever> retriever{new BoostOptionsRetriever(true, argc, argv)};
@@ -206,10 +190,10 @@ int mainNoCatch(int argc, char** argv)
   overridePipeline(configContext, specs);
   overrideLabels(configContext, specs);
   for (auto& spec : specs) {
-    UserCustomizationsHelper::userDefinedCustomization(spec.requiredServices, 0);
+    UserCustomizationsHelper::userDefinedCustomization(spec.requiredServices);
   }
   std::vector<ChannelConfigurationPolicy> channelPolicies;
-  UserCustomizationsHelper::userDefinedCustomization(channelPolicies, 0);
+  UserCustomizationsHelper::userDefinedCustomization(channelPolicies);
   auto defaultChannelPolicies = ChannelConfigurationPolicy::createDefaultPolicies(configContext);
   channelPolicies.insert(std::end(channelPolicies), std::begin(defaultChannelPolicies), std::end(defaultChannelPolicies));
   return doMain(argc, argv, specs,
@@ -229,7 +213,7 @@ int main(int argc, char** argv)
 
   char* idstring = getIdString(argc, argv);
   o2::framework::OnWorkflowTerminationHook onWorkflowTerminationHook;
-  UserCustomizationsHelper::userDefinedCustomization(onWorkflowTerminationHook, 0);
+  UserCustomizationsHelper::userDefinedCustomization(onWorkflowTerminationHook);
   onWorkflowTerminationHook(idstring);
   doDefaultWorkflowTerminationHook();