[qpid-proton] 02/03: PROTON-2665: Convert C++ broker example to use lambdas

[as...@apache.org]

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astitcher pushed a commit to branch main
in repository https://gitbox.apache.org/repos/asf/qpid-proton.git

commit a131afbc251821cdeacbba074133e9cd6dd51282
Author: Andrew Stitcher <as...@apache.org>
AuthorDate: Wed Jan 4 11:15:12 2023 -0500

    PROTON-2665: Convert C++ broker example to use lambdas
    
    We can make the code more idiomatic by using C++11 features.
---
 cpp/examples/broker.cpp | 37 +++++++++++++++++++++++--------------
 1 file changed, 23 insertions(+), 14 deletions(-)

diff --git a/cpp/examples/broker.cpp b/cpp/examples/broker.cpp
index 30b602821..bcf8ab6ae 100644
--- a/cpp/examples/broker.cpp
+++ b/cpp/examples/broker.cpp
@@ -141,7 +141,9 @@ class Queue {
             DOUT(std::cerr << "(" << current_->second << ") ";);
             if (current_->second>0) {
                 DOUT(std::cerr << current_->first << " ";);
-                current_->first->add(make_work(&Sender::sendMsg, current_->first, messages_.front()));
+                auto msg = messages_.front();
+                auto sender = current_->first;
+                sender->add([=]{sender->sendMsg(msg);});
                 messages_.pop_front();
                 --current_->second;
                 ++current_;
@@ -180,14 +182,15 @@ public:
         // If we're about to erase the current subscription move on
         if (current_ != subscriptions_.end() && current_->first==s) ++current_;
         subscriptions_.erase(s);
-        s->add(make_work(&Sender::unsubscribed, s));
+        s->add([=]{s->unsubscribed();});
     }
 };
 
 // We have credit to send a message.
 void Sender::on_sendable(proton::sender &sender) {
     if (queue_) {
-        queue_->add(make_work(&Queue::flow, queue_, this, sender.credit()));
+        auto credit = sender.credit();
+        queue_->add([=]{queue_->flow(this, credit);});
     } else {
         pending_credit_ = sender.credit();
     }
@@ -195,7 +198,7 @@ void Sender::on_sendable(proton::sender &sender) {
 
 void Sender::on_sender_close(proton::sender &sender) {
     if (queue_) {
-        queue_->add(make_work(&Queue::unsubscribe, queue_, this));
+        queue_->add([=]{queue_->unsubscribe(this);});
     } else {
         // TODO: Is it possible to be closed before we get the queue allocated?
         // If so, we should have a way to mark the sender deleted, so we can delete
@@ -209,13 +212,16 @@ void Sender::boundQueue(Queue* q, std::string qn) {
     queue_ = q;
     queue_name_ = qn;
 
-    q->add(make_work(&Queue::subscribe, q, this));
     sender_.open(proton::sender_options()
         .source((proton::source_options().address(queue_name_)))
         .handler(*this));
-    if (pending_credit_>0) {
-        queue_->add(make_work(&Queue::flow, queue_, this, pending_credit_));
-    }
+    auto credit = pending_credit_;
+    q->add([=]{
+        q->subscribe(this);
+        if (credit>0) {
+            q->flow(this, credit);
+        }
+    });
     std::cout << "sending from " << queue_name_ << std::endl;
 }
 
@@ -239,7 +245,8 @@ class Receiver : public proton::messaging_handler {
     void queueMsgs() {
         DOUT(std::cerr << "Receiver: " << this << " queueing " << messages_.size() << " msgs to: " << queue_ << "\n";);
         while (!messages_.empty()) {
-            queue_->add(make_work(&Queue::queueMsg, queue_, messages_.front()));
+            auto msg = messages_.front();
+            queue_->add([=]{queue_->queueMsg(msg);});
             messages_.pop_front();
         }
     }
@@ -297,7 +304,7 @@ public:
         } else {
             q = i->second;
         }
-        connection.add(make_work(&T::boundQueue, &connection, q, qn));
+        connection.add([=, &connection] {connection.boundQueue(q, qn);});
     }
 
     void findQueueSender(Sender* s, std::string qn) {
@@ -327,14 +334,14 @@ public:
         std::string qn = sender.source().dynamic() ? "" : sender.source().address();
         Sender* s = new Sender(sender, senders_);
         senders_[sender] = s;
-        queue_manager_.add(make_work(&QueueManager::findQueueSender, &queue_manager_, s, qn));
+        queue_manager_.add([=]{queue_manager_.findQueueSender(s, qn);});
     }
 
     // A receiver receives messages from a publisher to a queue.
     void on_receiver_open(proton::receiver &receiver) override {
         std::string qname = receiver.target().address();
         Receiver* r = new Receiver(receiver);
-        queue_manager_.add(make_work(&QueueManager::findQueueReceiver, &queue_manager_, r, qname));
+        queue_manager_.add([=]{queue_manager_.findQueueReceiver(r, qname);});
     }
 
     void on_session_close(proton::session &session) override {
@@ -344,7 +351,8 @@ public:
             if (j == senders_.end()) continue;
             Sender* s = j->second;
             if (s->queue_) {
-                s->queue_->add(make_work(&Queue::unsubscribe, s->queue_, s));
+                auto q = s->queue_;
+                s->queue_->add([=]{q->unsubscribe(s);});
             }
             senders_.erase(j);
         }
@@ -362,7 +370,8 @@ public:
             if (j == senders_.end()) continue;
             Sender* s = j->second;
             if (s->queue_) {
-                s->queue_->add(make_work(&Queue::unsubscribe, s->queue_, s));
+                auto q = s->queue_;
+                s->queue_->add([=]{q->unsubscribe(s);});
             }
         }
         delete this;            // All done.


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