Support Boost 1.70:

This patch removes calls to several deprecated asio functions.

* `io_service::post` becomes `post` (free function)
* `io_service::work` becomes `executor_work_guard`
* `io_service::wrap` becomes `bind_executor`
* `get_io_context`   becomes `get_executor` or `get_executor().context()`

This patch was tested with boost 1.69 and 1.70. The functions
`ripple::get_lowest_layer` and `beast::create_waitable_timer` are required to
handle a breaking difference between these versions. When rippled no longer
needs to support pre 1.70 boost versions, both of these functions may be
removed, and the waitable timer injections may also be removed.

src/ripple/overlay/impl/PeerImp.cpp

@@ -66,8 +66,8 @@ PeerImp::PeerImp (Application& app, id_t id, endpoint_type remote_endpoint,
     , ssl_bundle_(std::move(ssl_bundle))
     , socket_ (ssl_bundle_->socket)
     , stream_ (ssl_bundle_->stream)
-    , strand_ (socket_.get_io_service())
-    , timer_ (socket_.get_io_service())
+    , strand_ (socket_.get_executor())
+    , timer_ (beast::create_waitable_timer<waitable_timer>(socket_))
     , remote_address_ (
         beast::IPAddressConversion::from_asio(remote_endpoint))
     , overlay_ (overlay)
@@ -102,7 +102,7 @@ void
 PeerImp::run()
 {
     if(! strand_.running_in_this_thread())
-        return strand_.post(std::bind (
+        return post(strand_, std::bind (
             &PeerImp::run, shared_from_this()));
     if (m_inbound)
     {
@@ -145,8 +145,7 @@ void
 PeerImp::stop()
 {
     if(! strand_.running_in_this_thread())
-        return strand_.post(std::bind (
-            &PeerImp::stop, shared_from_this()));
+        return post(strand_, std::bind(&PeerImp::stop, shared_from_this()));
     if (socket_.is_open())
     {
         // The rationale for using different severity levels is that
@@ -172,8 +171,7 @@ void
 PeerImp::send (Message::pointer const& m)
 {
     if (! strand_.running_in_this_thread())
-        return strand_.post(std::bind (
-            &PeerImp::send, shared_from_this(), m));
+        return post(strand_, std::bind(&PeerImp::send, shared_from_this(), m));
     if(gracefulClose_)
         return;
     if(detaching_)
@@ -204,11 +202,16 @@ PeerImp::send (Message::pointer const& m)
     if(sendq_size != 0)
         return;
 
-    boost::asio::async_write (stream_, boost::asio::buffer(
-        send_queue_.front()->getBuffer()), strand_.wrap(std::bind(
-            &PeerImp::onWriteMessage, shared_from_this(),
+    boost::asio::async_write(
+        stream_,
+        boost::asio::buffer(send_queue_.front()->getBuffer()),
+        bind_executor(
+            strand_,
+            std::bind(
+                &PeerImp::onWriteMessage,
+                shared_from_this(),
                 std::placeholders::_1,
-                    std::placeholders::_2)));
+                std::placeholders::_2)));
 }
 
 void
@@ -438,9 +441,12 @@ void
 PeerImp::fail(std::string const& reason)
 {
     if(! strand_.running_in_this_thread())
-        return strand_.post(std::bind (
-            (void(Peer::*)(std::string const&))&PeerImp::fail,
-                shared_from_this(), reason));
+        return post(
+            strand_,
+            std::bind(
+                (void (Peer::*)(std::string const&)) & PeerImp::fail,
+                shared_from_this(),
+                reason));
     if (socket_.is_open())
     {
         JLOG (journal_.warn()) <<
@@ -498,8 +504,10 @@ PeerImp::gracefulClose()
     if (send_queue_.size() > 0)
         return;
     setTimer();
-    stream_.async_shutdown(strand_.wrap(std::bind(&PeerImp::onShutdown,
-        shared_from_this(), std::placeholders::_1)));
+    stream_.async_shutdown(bind_executor(
+        strand_,
+        std::bind(
+            &PeerImp::onShutdown, shared_from_this(), std::placeholders::_1)));
 }
 
 void
@@ -514,8 +522,10 @@ PeerImp::setTimer()
         JLOG(journal_.error()) << "setTimer: " << ec.message();
         return;
     }
-    timer_.async_wait(strand_.wrap(std::bind(&PeerImp::onTimer,
-        shared_from_this(), std::placeholders::_1)));
+    timer_.async_wait(bind_executor(
+        strand_,
+        std::bind(
+            &PeerImp::onTimer, shared_from_this(), std::placeholders::_1)));
 }
 
 // convenience for ignoring the error code
@@ -709,9 +719,14 @@ PeerImp::onWriteResponse (error_code ec, std::size_t bytes_transferred)
     if (write_buffer_.size() == 0)
         return doProtocolStart();
 
-    stream_.async_write_some (write_buffer_.data(),
-        strand_.wrap (std::bind (&PeerImp::onWriteResponse,
-            shared_from_this(), std::placeholders::_1,
+    stream_.async_write_some(
+        write_buffer_.data(),
+        bind_executor(
+            strand_,
+            std::bind(
+                &PeerImp::onWriteResponse,
+                shared_from_this(),
+                std::placeholders::_1,
                 std::placeholders::_2)));
 }
 
@@ -785,9 +800,14 @@ PeerImp::onReadMessage (error_code ec, std::size_t bytes_transferred)
         read_buffer_.consume (bytes_consumed);
     }
     // Timeout on writes only
-    stream_.async_read_some (read_buffer_.prepare (Tuning::readBufferBytes),
-        strand_.wrap (std::bind (&PeerImp::onReadMessage,
-            shared_from_this(), std::placeholders::_1,
+    stream_.async_read_some(
+        read_buffer_.prepare(Tuning::readBufferBytes),
+        bind_executor(
+            strand_,
+            std::bind(
+                &PeerImp::onReadMessage,
+                shared_from_this(),
+                std::placeholders::_1,
                 std::placeholders::_2)));
 }
 
@@ -814,17 +834,25 @@ PeerImp::onWriteMessage (error_code ec, std::size_t bytes_transferred)
     if (! send_queue_.empty())
     {
         // Timeout on writes only
-        return boost::asio::async_write (stream_, boost::asio::buffer(
-            send_queue_.front()->getBuffer()), strand_.wrap(std::bind(
-                &PeerImp::onWriteMessage, shared_from_this(),
+        return boost::asio::async_write(
+            stream_,
+            boost::asio::buffer(send_queue_.front()->getBuffer()),
+            bind_executor(
+                strand_,
+                std::bind(
+                    &PeerImp::onWriteMessage,
+                    shared_from_this(),
                     std::placeholders::_1,
-                        std::placeholders::_2)));
+                    std::placeholders::_2)));
     }
 
     if (gracefulClose_)
     {
-        return stream_.async_shutdown(strand_.wrap(std::bind(
-            &PeerImp::onShutdown, shared_from_this(),
+        return stream_.async_shutdown(bind_executor(
+            strand_,
+            std::bind(
+                &PeerImp::onShutdown,
+                shared_from_this(),
                 std::placeholders::_1)));
     }
 }
@@ -1816,9 +1844,12 @@ void PeerImp::check ()
     if (reject)
     {
         overlay_.peerFinder().on_failure (slot_);
-        strand_.post (std::bind (
-            (void (PeerImp::*)(std::string const&)) &PeerImp::fail,
-                shared_from_this(), "Not useful"));
+        post(
+            strand_,
+            std::bind(
+                (void (PeerImp::*)(std::string const&)) & PeerImp::fail,
+                shared_from_this(),
+                "Not useful"));
     }
 }