Bump the C++ standard to 17 (#525)

- Replace `boost::optional` with `std::optional`
- Replace `boost::any` with `std::any`
- Use `std::weak_from_this` to create a `weak_ptr` from a `shared_ptr`
- Leverage initializers for if to simplify code

Author: BewareMyPower

CMakeLists.txt

@@ -83,6 +83,10 @@ set(THREADS_PREFER_PTHREAD_FLAG TRUE)
 find_package(Threads REQUIRED)
 MESSAGE(STATUS "Threads library: " ${CMAKE_THREAD_LIBS_INIT})
 
+if (NOT CMAKE_CXX_STANDARD)
+    set(CMAKE_CXX_STANDARD 17)
+endif ()
+
 # Compiler specific configuration:
 # https://stackoverflow.com/questions/10046114/in-cmake-how-can-i-test-if-the-compiler-is-clang
 if (CMAKE_CXX_COMPILER_ID STREQUAL "MSVC")
@@ -112,9 +116,6 @@ set(AUTOGEN_DIR ${PROJECT_BINARY_DIR}/generated)
 file(MAKE_DIRECTORY ${AUTOGEN_DIR})
 
 if (INTEGRATE_VCPKG)
-    if (NOT CMAKE_CXX_STANDARD)
-        set(CMAKE_CXX_STANDARD 11)
-    endif ()
     set(CMAKE_C_STANDARD 11)
     set(Boost_NO_BOOST_CMAKE ON)
     find_package(Boost REQUIRED)

LegacyFindPackages.cmake

@@ -270,6 +270,11 @@ if (MSVC)
         string(REGEX REPLACE "/MD" "/MT" CMAKE_CXX_FLAGS_DEBUG ${CMAKE_CXX_FLAGS_DEBUG})
         string(REGEX REPLACE "/MD" "/MT" CMAKE_CXX_FLAGS_RELEASE ${CMAKE_CXX_FLAGS_RELEASE})
         string(REGEX REPLACE "/MD" "/MT" CMAKE_CXX_FLAGS_RELWITHDEBINFO ${CMAKE_CXX_FLAGS_RELWITHDEBINFO})
+        if (NOT CMAKE_CL_64)
+            # When building with a 32-bit cl.exe, the virtual address space is limited to 2GB, which could be
+            # reached with /O2 optimization. Use /Os for smaller code size.
+            string(REGEX REPLACE "/O2" "/Os" CMAKE_CXX_FLAGS_RELEASE ${CMAKE_CXX_FLAGS_RELEASE})
+        endif ()
         message(STATUS "CMAKE_CXX_FLAGS_DEBUG: " ${CMAKE_CXX_FLAGS_DEBUG})
         message(STATUS "CMAKE_CXX_FLAGS_RELEASE: " ${CMAKE_CXX_FLAGS_RELEASE})
         message(STATUS "CMAKE_CXX_FLAGS_RELWITHDEBINFO: " ${CMAKE_CXX_FLAGS_RELWITHDEBINFO})

README.md

@@ -57,6 +57,9 @@ cmake -B build -DINTEGRATE_VCPKG=ON
 cmake --build build -j8
 ```
 
+> - Before 4.0.0, C++11 is required.
+> - Since 4.0.0, C++17 is required.
+
 The 1st step will download vcpkg and then install all dependencies according to the version description in [vcpkg.json](./vcpkg.json). The 2nd step will build the Pulsar C++ libraries under `./build/lib/`, where `./build` is the CMake build directory.
 
 > You can also add the CMAKE_TOOLCHAIN_FILE option if your system already have vcpkg installed.

lib/AckGroupingTrackerEnabled.cc

@@ -198,10 +198,9 @@ void AckGroupingTrackerEnabled::scheduleTimer() {
     std::lock_guard<std::mutex> lock(this->mutexTimer_);
     this->timer_ = this->executor_->createDeadlineTimer();
     this->timer_->expires_after(std::chrono::milliseconds(std::max(1L, this->ackGroupingTimeMs_)));
-    std::weak_ptr<AckGroupingTracker> weakSelf = shared_from_this();
+    auto weakSelf = weak_from_this();
     this->timer_->async_wait([this, weakSelf](const ASIO_ERROR& ec) -> void {
-        auto self = weakSelf.lock();
-        if (self && !ec) {
+        if (auto self = weakSelf.lock(); self && !ec) {
             auto consumer = consumer_.lock();
             if (!consumer || consumer->isClosingOrClosed()) {
                 return;

lib/ClientConnection.cc

@@ -21,7 +21,6 @@
 #include <openssl/x509.h>
 #include <pulsar/MessageIdBuilder.h>
 
-#include <boost/optional.hpp>
 #include <fstream>
 
 #include "AsioDefines.h"
@@ -1127,19 +1126,19 @@ void ClientConnection::sendPendingCommands() {
 
     if (--pendingWriteOperations_ > 0) {
         assert(!pendingWriteBuffers_.empty());
-        boost::any any = pendingWriteBuffers_.front();
+        auto any = pendingWriteBuffers_.front();
         pendingWriteBuffers_.pop_front();
 
         auto self = shared_from_this();
         if (any.type() == typeid(SharedBuffer)) {
-            SharedBuffer buffer = boost::any_cast<SharedBuffer>(any);
+            SharedBuffer buffer = std::any_cast<SharedBuffer>(any);
             asyncWrite(buffer.const_asio_buffer(),
                        customAllocWriteHandler(
                            [this, self, buffer](const ASIO_ERROR& err, size_t) { handleSend(err, buffer); }));
         } else {
             assert(any.type() == typeid(std::shared_ptr<SendArguments>));
 
-            auto args = boost::any_cast<std::shared_ptr<SendArguments>>(any);
+            auto args = std::any_cast<std::shared_ptr<SendArguments>>(any);
             BaseCommand outgoingCmd;
             PairSharedBuffer buffer =
                 Commands::newSend(outgoingBuffer_, outgoingCmd, getChecksumType(), *args);
@@ -1702,9 +1701,9 @@ void ClientConnection::handleProducerSuccess(const proto::CommandProducerSuccess
                 data.schemaVersion = producerSuccess.schema_version();
             }
             if (producerSuccess.has_topic_epoch()) {
-                data.topicEpoch = boost::make_optional(producerSuccess.topic_epoch());
+                data.topicEpoch = std::make_optional(producerSuccess.topic_epoch());
             } else {
-                data.topicEpoch = boost::none;
+                data.topicEpoch = std::nullopt;
             }
             requestData.promise.setValue(data);
             cancelTimer(*requestData.timer);
@@ -1805,7 +1804,7 @@ void ClientConnection::handleTopicMigrated(const proto::CommandTopicMigrated& co
     }
 }
 
-boost::optional<std::string> ClientConnection::getAssignedBrokerServiceUrl(
+optional<std::string> ClientConnection::getAssignedBrokerServiceUrl(
     const proto::CommandCloseProducer& closeProducer) {
     if (tlsSocket_) {
         if (closeProducer.has_assignedbrokerserviceurltls()) {
@@ -1814,10 +1813,10 @@ boost::optional<std::string> ClientConnection::getAssignedBrokerServiceUrl(
     } else if (closeProducer.has_assignedbrokerserviceurl()) {
         return closeProducer.assignedbrokerserviceurl();
     }
-    return boost::none;
+    return {};
 }
 
-boost::optional<std::string> ClientConnection::getAssignedBrokerServiceUrl(
+optional<std::string> ClientConnection::getAssignedBrokerServiceUrl(
     const proto::CommandCloseConsumer& closeConsumer) {
     if (tlsSocket_) {
         if (closeConsumer.has_assignedbrokerserviceurltls()) {
@@ -1826,7 +1825,7 @@ boost::optional<std::string> ClientConnection::getAssignedBrokerServiceUrl(
     } else if (closeConsumer.has_assignedbrokerserviceurl()) {
         return closeConsumer.assignedbrokerserviceurl();
     }
-    return boost::none;
+    return {};
 }
 
 void ClientConnection::handleCloseProducer(const proto::CommandCloseProducer& closeProducer) {

lib/ClientConnection.h

@@ -22,6 +22,7 @@
 #include <pulsar/ClientConfiguration.h>
 #include <pulsar/defines.h>
 
+#include <any>
 #include <atomic>
 #include <cstdint>
 #ifdef USE_ASIO
@@ -37,8 +38,6 @@
 #include <boost/asio/ssl/stream.hpp>
 #include <boost/asio/strand.hpp>
 #endif
-#include <boost/any.hpp>
-#include <boost/optional.hpp>
 #include <deque>
 #include <functional>
 #include <memory>
@@ -53,6 +52,9 @@
 #include "SharedBuffer.h"
 #include "TimeUtils.h"
 #include "UtilAllocator.h"
+
+using std::optional;
+
 namespace pulsar {
 
 class PulsarFriend;
@@ -108,7 +110,7 @@ struct ResponseData {
     std::string producerName;
     int64_t lastSequenceId;
     std::string schemaVersion;
-    boost::optional<uint64_t> topicEpoch;
+    optional<uint64_t> topicEpoch;
 };
 
 typedef std::shared_ptr<std::vector<std::string>> NamespaceTopicsPtr;
@@ -141,10 +143,6 @@ class PULSAR_PUBLIC ClientConnection : public std::enable_shared_from_this<Clien
                      ConnectionPool& pool, size_t poolIndex);
     ~ClientConnection();
 
-#if __cplusplus < 201703L
-    std::weak_ptr<ClientConnection> weak_from_this() noexcept { return shared_from_this(); }
-#endif
-
     /*
      * starts tcp connect_async
      * @return future<ConnectionPtr> which is not yet set
@@ -378,7 +376,7 @@ class PULSAR_PUBLIC ClientConnection : public std::enable_shared_from_this<Clien
     typedef std::unique_lock<std::mutex> Lock;
 
     // Pending buffers to write on the socket
-    std::deque<boost::any> pendingWriteBuffers_;
+    std::deque<std::any> pendingWriteBuffers_;
     int pendingWriteOperations_ = 0;
 
     SharedBuffer outgoingBuffer_;
@@ -426,8 +424,8 @@ class PULSAR_PUBLIC ClientConnection : public std::enable_shared_from_this<Clien
     void handleGetTopicOfNamespaceResponse(const proto::CommandGetTopicsOfNamespaceResponse&);
     void handleGetSchemaResponse(const proto::CommandGetSchemaResponse&);
     void handleAckResponse(const proto::CommandAckResponse&);
-    boost::optional<std::string> getAssignedBrokerServiceUrl(const proto::CommandCloseProducer&);
-    boost::optional<std::string> getAssignedBrokerServiceUrl(const proto::CommandCloseConsumer&);
+    optional<std::string> getAssignedBrokerServiceUrl(const proto::CommandCloseProducer&);
+    optional<std::string> getAssignedBrokerServiceUrl(const proto::CommandCloseConsumer&);
     std::string getMigratedBrokerServiceUrl(const proto::CommandTopicMigrated&);
     // This method must be called when `mutex_` is held
     void unsafeRemovePendingRequest(long requestId);

lib/Commands.cc

@@ -34,6 +34,7 @@
 #include "OpSendMsg.h"
 #include "PulsarApi.pb.h"
 #include "Url.h"
+#include "boost/throw_exception.hpp"
 #include "checksum/ChecksumProvider.h"
 
 using namespace pulsar;
@@ -329,7 +330,7 @@ SharedBuffer Commands::newAuthResponse(const AuthenticationPtr& authentication,
 SharedBuffer Commands::newSubscribe(const std::string& topic, const std::string& subscription,
                                     uint64_t consumerId, uint64_t requestId, CommandSubscribe_SubType subType,
                                     const std::string& consumerName, SubscriptionMode subscriptionMode,
-                                    boost::optional<MessageId> startMessageId, bool readCompacted,
+                                    optional<MessageId> startMessageId, bool readCompacted,
                                     const std::map<std::string, std::string>& metadata,
                                     const std::map<std::string, std::string>& subscriptionProperties,
                                     const SchemaInfo& schemaInfo,
@@ -416,7 +417,7 @@ SharedBuffer Commands::newProducer(const std::string& topic, uint64_t producerId
                                    const std::map<std::string, std::string>& metadata,
                                    const SchemaInfo& schemaInfo, uint64_t epoch,
                                    bool userProvidedProducerName, bool encrypted,
-                                   ProducerAccessMode accessMode, boost::optional<uint64_t> topicEpoch,
+                                   ProducerAccessMode accessMode, optional<uint64_t> topicEpoch,
                                    const std::string& initialSubscriptionName) {
     BaseCommand cmd;
     cmd.set_type(BaseCommand::PRODUCER);

lib/Commands.h

@@ -25,7 +25,7 @@
 #include <pulsar/Schema.h>
 #include <pulsar/defines.h>
 
-#include <boost/optional.hpp>
+#include <optional>
 #include <set>
 
 #include "ProtoApiEnums.h"
@@ -41,6 +41,7 @@ class MessageIdImpl;
 using MessageIdImplPtr = std::shared_ptr<MessageIdImpl>;
 class BitSet;
 struct SendArguments;
+using std::optional;
 
 namespace proto {
 class BaseCommand;
@@ -102,14 +103,16 @@ class Commands {
     static PairSharedBuffer newSend(SharedBuffer& headers, proto::BaseCommand& cmd, ChecksumType checksumType,
                                     const SendArguments& args);
 
-    static SharedBuffer newSubscribe(
-        const std::string& topic, const std::string& subscription, uint64_t consumerId, uint64_t requestId,
-        CommandSubscribe_SubType subType, const std::string& consumerName, SubscriptionMode subscriptionMode,
-        boost::optional<MessageId> startMessageId, bool readCompacted,
-        const std::map<std::string, std::string>& metadata,
-        const std::map<std::string, std::string>& subscriptionProperties, const SchemaInfo& schemaInfo,
-        CommandSubscribe_InitialPosition subscriptionInitialPosition, bool replicateSubscriptionState,
-        const KeySharedPolicy& keySharedPolicy, int priorityLevel = 0);
+    static SharedBuffer newSubscribe(const std::string& topic, const std::string& subscription,
+                                     uint64_t consumerId, uint64_t requestId,
+                                     CommandSubscribe_SubType subType, const std::string& consumerName,
+                                     SubscriptionMode subscriptionMode, optional<MessageId> startMessageId,
+                                     bool readCompacted, const std::map<std::string, std::string>& metadata,
+                                     const std::map<std::string, std::string>& subscriptionProperties,
+                                     const SchemaInfo& schemaInfo,
+                                     CommandSubscribe_InitialPosition subscriptionInitialPosition,
+                                     bool replicateSubscriptionState, const KeySharedPolicy& keySharedPolicy,
+                                     int priorityLevel = 0);
 
     static SharedBuffer newUnsubscribe(uint64_t consumerId, uint64_t requestId);
 
@@ -118,7 +121,7 @@ class Commands {
                                     const std::map<std::string, std::string>& metadata,
                                     const SchemaInfo& schemaInfo, uint64_t epoch,
                                     bool userProvidedProducerName, bool encrypted,
-                                    ProducerAccessMode accessMode, boost::optional<uint64_t> topicEpoch,
+                                    ProducerAccessMode accessMode, optional<uint64_t> topicEpoch,
                                     const std::string& initialSubscriptionName);
 
     static SharedBuffer newAck(uint64_t consumerId, int64_t ledgerId, int64_t entryId, const BitSet& ackSet,