DPL: Ensure lifecycle of MessageSet

By exploiting the fact that messages go through the "add" method
only once, we make sure that they get forwarded as soon as possible.

Author: ktf

Framework/Core/CMakeLists.txt

@@ -105,6 +105,7 @@ o2_add_library(Framework
                        src/StringContext.cxx
                        src/LogParsingHelpers.cxx
                        src/MessageContext.cxx
+                       src/MessageSet.cxx
                        src/Metric2DViewIndex.cxx
                        src/SimpleOptionsRetriever.cxx
                        src/O2ControlHelpers.cxx

Framework/Core/include/Framework/DataRelayer.h

@@ -104,6 +104,8 @@ class DataRelayer
               TimesliceIndex&,
               ServiceRegistryRef);
 
+  ~DataRelayer();
+
   /// This invokes the appropriate `InputRoute::danglingChecker` on every
   /// entry in the cache and if it returns true, it creates a new
   /// cache entry by invoking the associated `InputRoute::expirationHandler`.

Framework/Core/include/Framework/MessageSet.h

@@ -1,4 +1,4 @@
-// Copyright 2019-2020 CERN and copyright holders of ALICE O2.
+// Copyright 2019-2025 CERN and copyright holders of ALICE O2.
 // See https://alice-o2.web.cern.ch/copyright for details of the copyright holders.
 // All rights not expressly granted are reserved.
 //
@@ -8,19 +8,47 @@
 // In applying this license CERN does not waive the privileges and immunities
 // granted to it by virtue of its status as an Intergovernmental Organization
 // or submit itself to any jurisdiction.
-#ifndef FRAMEWORK_MESSAGESET_H
-#define FRAMEWORK_MESSAGESET_H
+#ifndef O2_FRAMEWORK_MESSAGESET_H_
+#define O2_FRAMEWORK_MESSAGESET_H_
 
 #include "Framework/PartRef.h"
+#include <Message.h>
+#include <fairmq/FwdDecls.h>
 #include <memory>
 #include <vector>
 #include <cassert>
+#include <concepts>
 
-namespace o2
-{
-namespace framework
+namespace o2::framework
 {
 
+template <typename T>
+concept MessageSetFiller = requires(T t, size_t n) {
+  { t(n) } -> std::same_as<fair::mq::MessagePtr>;
+};
+
+template <typename T>
+concept MessageSetCounter = requires(fair::mq::MessagePtr && (*t)(fair::mq::MessagePtr&&), fair::mq::MessagePtr&& ref) {
+  { t(std::forward<fair::mq::MessagePtr>(ref)) } -> std::same_as<fair::mq::MessagePtr&&>;
+};
+
+template <typename T>
+concept MessageSetDisposer = requires(void (*t)(fair::mq::MessagePtr&&), fair::mq::MessagePtr&& ref) {
+  { t(std::forward<fair::mq::MessagePtr>(ref)) } -> std::same_as<void>;
+};
+
+// Sometimes we fill from a PartRef, e.g. (header, payload pair)
+// So we need some special code for it.
+template <typename T>
+concept PartRefFiller = requires(T t, size_t n) {
+  { t(n) } -> std::same_as<PartRef>;
+};
+
+template <typename T>
+concept PartRefCounter = requires(PartRef && (*t)(PartRef&&), PartRef&& ref) {
+  { t(std::forward<PartRef>(ref)) } -> std::same_as<PartRef&&>;
+};
+
 /// A set of inflight messages.
 /// The messages are stored in a linear vector. Originally, an O2 message was
 /// comprised of a header-payload pair which makes indexing of pairs in the
@@ -31,20 +59,30 @@ namespace framework
 /// O2 message model. For this purpose, also the pair index is filled and can
 /// be used to access header and payload associated with a pair
 struct MessageSet {
+  static auto passthrough(fair::mq::MessagePtr&& ref) -> fair::mq::MessagePtr&& { return std::forward<fair::mq::MessagePtr>(ref); }
+  static auto passthrough_partref(o2::framework::PartRef&& ref) -> o2::framework::PartRef&& { return std::forward<o2::framework::PartRef>(ref); }
+  // Use this when you want to delete the messages on clear.
+  static auto destroy_message(fair::mq::MessagePtr&& ref) -> void
+  {
+    fair::mq::MessagePtr toDelete(nullptr);
+    ref.swap(toDelete);
+  }
+  static auto noop(fair::mq::MessagePtr&& ref) -> void {}
+  static auto assert_empty(fair::mq::MessagePtr&& ref) -> void { assert(ref.get() == nullptr); }
+  static auto enforce_empty(fair::mq::MessagePtr&& ref) -> void;
+
   struct Index {
-    Index(size_t p, size_t s) : position(p), size(s) {}
     size_t position = 0;
     size_t size = 0;
   };
   // linear storage of messages
-  std::vector<fair::mq::MessagePtr> messages;
+  std::vector<std::unique_ptr<fair::mq::Message>> messages;
   // message map describes O2 messages consisting of a header message and
   // payload message(s), index describes position in the linear storage
   std::vector<Index> messageMap;
   // pair map describes all messages in one sequence of header-payload pairs and
   // where in the message index the associated header and payload can be found
   struct PairMapping {
-    PairMapping(size_t partId, size_t payloadId) : partIndex(partId), payloadIndex(payloadId) {}
     // O2 message where the pair is located in
     size_t partIndex = 0;
     // payload index within the O2 message
@@ -57,17 +95,44 @@ struct MessageSet {
   {
   }
 
-  template <typename F>
-  MessageSet(F getter, size_t size)
+  // Allow creating a message set via a getter.
+  // The counting function will be invoked only
+  // once per message. If you want to augment a
+  // MessageSet use the merge method.
+  MessageSet(MessageSetFiller auto getter, size_t size, MessageSetCounter auto counter)
+    : messages(), messageMap(), pairMap()
+  {
+    messages.reserve(size);
+    pairMap.reserve(size - 1);
+    messageMap.emplace_back(Index{.position = 0, .size = size - 1});
+    for (size_t i = 0; i < size; ++i) {
+      if (i > 0) {
+        pairMap.emplace_back(0, i - 1);
+      }
+      messages.emplace_back(std::move(counter(getter(i))));
+    }
+  }
+
+  MessageSet(PartRefFiller auto filler, size_t nPartRef, PartRefCounter auto counter)
     : messages(), messageMap(), pairMap()
   {
-    add(std::forward<F>(getter), size);
+    messages.reserve(2 * nPartRef);    // Beacause messages contains all the messages
+    messageMap.reserve(nPartRef);      // Because the message map tracks how many (header, payload0, payload1 ...) there are
+    pairMap.reserve(2 * nPartRef - 1); // Because pairMap tracks (header, payload0), (header, payload1), etc.
+
+    for (size_t i = 0; i < nPartRef; ++i) {
+      pairMap.emplace_back(PairMapping{.partIndex = messageMap.size(), .payloadIndex = 0}); // Because this is the first one
+      messageMap.emplace_back(Index{.position = i, .size = 1});                             // Because a PartRef only has 2 messages (and 1 payload)
+      o2::framework::PartRef ref = counter(filler(i));
+      messages.emplace_back(std::move(ref.header));
+      messages.emplace_back(std::move(ref.payload));
+    }
   }
 
   MessageSet(MessageSet&& other)
     : messages(std::move(other.messages)), messageMap(std::move(other.messageMap)), pairMap(std::move(other.pairMap))
   {
-    other.clear();
+    other.clear(MessageSet::noop);
   }
 
   MessageSet& operator=(MessageSet&& other)
@@ -78,107 +143,98 @@ struct MessageSet {
     messages = std::move(other.messages);
     messageMap = std::move(other.messageMap);
     pairMap = std::move(other.pairMap);
-    other.clear();
+    other.clear(MessageSet::noop);
     return *this;
   }
 
+  ~MessageSet();
+
   /// get number of in-flight O2 messages
-  size_t size() const
+  [[nodiscard]] size_t size() const
   {
     return messageMap.size();
   }
 
   /// get number of header-payload pairs
-  size_t getNumberOfPairs() const
+  [[nodiscard]] size_t getNumberOfPairs() const
   {
     return pairMap.size();
   }
 
   /// get number of payloads for an in-flight message
-  size_t getNumberOfPayloads(size_t mi) const
+  [[nodiscard]] size_t getNumberOfPayloads(size_t mi) const
   {
     return messageMap[mi].size;
   }
 
   /// clear the set
-  void clear()
+  void clear(MessageSetDisposer auto dispose)
   {
+    for (auto& message : messages) {
+      dispose(std::move(message));
+    }
     messages.clear();
     messageMap.clear();
     pairMap.clear();
   }
 
-  // this is more or less legacy
-  // PartRef has been earlier used to store fixed header-payload pairs
-  // reset the set and store content of the part ref
-  void reset(PartRef&& ref)
-  {
-    clear();
-    add(std::move(ref));
-  }
-
-  // this is more or less legacy
-  // PartRef has been earlier used to store fixed header-payload pairs
-  // add  content of the part ref
-  void add(PartRef&& ref)
-  {
-    pairMap.emplace_back(messageMap.size(), 0);
-    messageMap.emplace_back(messages.size(), 1);
-    messages.emplace_back(std::move(ref.header));
-    messages.emplace_back(std::move(ref.payload));
-  }
-
-  /// add an O2 message
-  template <typename F>
-  void add(F getter, size_t size)
+  /// Add messages in bulk. We are guaranteed that this
+  /// function is executed only once for each incoming message
+  /// so it can be used to trigger the early forwarding.
+  ///
+  void merge(MessageSet&& other)
   {
     auto partid = messageMap.size();
-    messageMap.emplace_back(messages.size(), size - 1);
-    for (size_t i = 0; i < size; ++i) {
+    messageMap.emplace_back(messages.size(), other.messages.size() - 1);
+    for (size_t i = 0; i < other.messages.size(); ++i) {
       if (i > 0) {
         pairMap.emplace_back(partid, i - 1);
       }
-      messages.emplace_back(std::move(getter(i)));
+      messages.emplace_back(std::move(other.messages[i]));
     }
+    // Every message should be removed once the MessageSet is
+    // merged.
+    other.clear(MessageSet::assert_empty);
   }
 
-  fair::mq::MessagePtr& header(size_t partIndex)
+  // This should really be used to give ownership to something else.
+  [[nodiscard]] std::unique_ptr<fair::mq::Message> extractHeader(size_t partIndex)
   {
-    return messages[messageMap[partIndex].position];
+    return std::move(messages[messageMap[partIndex].position]);
   }
 
-  fair::mq::MessagePtr& payload(size_t partIndex, size_t payloadIndex = 0)
+  [[nodiscard]] std::unique_ptr<fair::mq::Message> extractPayload(size_t partIndex, size_t payloadIndex = 0)
   {
     assert(partIndex < messageMap.size());
     assert(messageMap[partIndex].position + payloadIndex + 1 < messages.size());
-    return messages[messageMap[partIndex].position + payloadIndex + 1];
+    return std::move(messages[messageMap[partIndex].position + payloadIndex + 1]);
   }
 
-  fair::mq::MessagePtr const& header(size_t partIndex) const
+  [[nodiscard]] std::unique_ptr<fair::mq::Message> const& header(size_t partIndex) const
   {
     return messages[messageMap[partIndex].position];
   }
 
-  fair::mq::MessagePtr const& payload(size_t partIndex, size_t payloadIndex = 0) const
+  [[nodiscard]] std::unique_ptr<fair::mq::Message> const& payload(size_t partIndex, size_t payloadIndex = 0) const
   {
     assert(partIndex < messageMap.size());
     assert(messageMap[partIndex].position + payloadIndex + 1 < messages.size());
     return messages[messageMap[partIndex].position + payloadIndex + 1];
   }
 
-  fair::mq::MessagePtr const& associatedHeader(size_t pos) const
+  [[nodiscard]] std::unique_ptr<fair::mq::Message> const& associatedHeader(size_t pos) const
   {
     return messages[messageMap[pairMap[pos].partIndex].position];
   }
 
-  fair::mq::MessagePtr const& associatedPayload(size_t pos) const
+  [[nodiscard]] std::unique_ptr<fair::mq::Message> const& associatedPayload(size_t pos) const
   {
     auto partIndex = pairMap[pos].partIndex;
     auto payloadIndex = pairMap[pos].payloadIndex;
     return messages[messageMap[partIndex].position + payloadIndex + 1];
   }
 };
 
-} // namespace framework
-} // namespace o2
-#endif // FRAMEWORK_MESSAGESET_H
+} // namespace o2::framework
+
+#endif // O2_FRAMEWORK_MESSAGESET_H_

Framework/Core/include/Framework/PartRef.h

@@ -8,16 +8,13 @@
 // In applying this license CERN does not waive the privileges and immunities
 // granted to it by virtue of its status as an Intergovernmental Organization
 // or submit itself to any jurisdiction.
-#ifndef FRAMEWORK_PARTREF_H
-#define FRAMEWORK_PARTREF_H
+#ifndef O2_FRAMEWORK_PARTREF_H_
+#define O2_FRAMEWORK_PARTREF_H_
 
 #include <memory>
-
 #include <fairmq/FwdDecls.h>
 
-namespace o2
-{
-namespace framework
+namespace o2::framework
 {
 
 /// Reference to an inflight part.
@@ -26,6 +23,6 @@ struct PartRef {
   std::unique_ptr<fair::mq::Message> payload;
 };
 
-} // namespace framework
-} // namespace o2
+} // namespace o2::framework
+
 #endif // FRAMEWORK_PARTREF_H