1 files changed, 136 insertions, 0 deletions
diff --git a/src/net/zmq.h b/src/net/zmq.h
new file mode 100644
index 000000000..c6a7fd743
--- /dev/null
+++ b/src/net/zmq.h
@@ -0,0 +1,136 @@
+// Copyright (c) 2019, The Monero Project
+//
+// All rights reserved.
+//
+// Redistribution and use in source and binary forms, with or without modification, are
+// permitted provided that the following conditions are met:
+//
+// 1. Redistributions of source code must retain the above copyright notice, this list of
+//    conditions and the following disclaimer.
+//
+// 2. Redistributions in binary form must reproduce the above copyright notice, this list
+//    of conditions and the following disclaimer in the documentation and/or other
+//    materials provided with the distribution.
+//
+// 3. Neither the name of the copyright holder nor the names of its contributors may be
+//    used to endorse or promote products derived from this software without specific
+//    prior written permission.
+//
+// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND ANY
+// EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
+// MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL
+// THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
+// PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
+// INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
+// STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF
+// THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
+#include <memory>
+#include <string>
+#include <system_error>
+#include <zmq.h>
+
+#include "common/expect.h"
+#include "span.h"
+
+//! If the expression is less than 0, return the current ZMQ error code.
+#define MONERO_ZMQ_CHECK(...)                      \
+    do                                             \
+    {                                              \
+        if (( __VA_ARGS__ ) < 0)                   \
+            return {::net::zmq::get_error_code()}; \
+    } while (0)
+
+//! Print a message followed by the current ZMQ error message. 
+#define MONERO_LOG_ZMQ_ERROR(...)                                                   \
+    do                                                                          \
+    {                                                                           \
+        MERROR( __VA_ARGS__ << ": " << ::net::zmq::get_error_code().message()); \
+    } while (0)
+
+//! Throw an exception with a custom `msg`, current ZMQ error code, filename, and line number.
+#define MONERO_ZMQ_THROW(msg)                         \
+    MONERO_THROW( ::net::zmq::get_error_code(), msg )
+
+namespace net
+{
+namespace zmq
+{
+    //! \return Category for ZMQ errors.
+    const std::error_category& error_category() noexcept;
+
+    //! \return `code` (usally from zmq_errno()`) using `net::zmq::error_category()`.
+    inline std::error_code make_error_code(int code) noexcept
+    {
+        return std::error_code{code, error_category()};
+    }
+
+    //! \return Error from `zmq_errno()` using `net::zmq::error_category()`.
+    inline std::error_code get_error_code() noexcept
+    {
+        return make_error_code(zmq_errno());
+    }
+
+    //! Calls `zmq_term`
+    class terminate
+    {
+        static void call(void* ptr) noexcept;
+    public:
+        void operator()(void* ptr) const noexcept
+        {
+            if (ptr)
+                call(ptr);
+        }
+    };
+
+    //! Calls `zmq_close`
+    struct close
+    {
+        void operator()(void* ptr) const noexcept
+        {
+            if (ptr)
+                zmq_close(ptr);
+        }
+    };
+
+    //! Unique ZMQ context handle, calls `zmq_term` on destruction.
+    using context = std::unique_ptr<void, terminate>;
+
+    //! Unique ZMQ socket handle, calls `zmq_close` on destruction.
+    using socket = std::unique_ptr<void, close>;
+
+    /*! Read all parts of the next message on `socket`. Blocks until the entire
+        next message (all parts) are read, or until `zmq_term` is called on the
+        `zmq_context` associated with `socket`. If the context is terminated,
+        `make_error_code(ETERM)` is returned.
+
+        \note This will automatically retry on `EINTR`, so exiting on
+            interrupts requires context termination.
+        \note If non-blocking behavior is requested on `socket` or by `flags`,
+            then `net::zmq::make_error_code(EAGAIN)` will be returned if this
+            would block.
+
+        \param socket Handle created with `zmq_socket`.
+        \param flags See `zmq_msg_read` for possible flags.
+     	\return Message payload read from `socket` or ZMQ error. */
+    expect<std::string> receive(void* socket, int flags = 0);
+
+    /*! Sends `payload` on `socket`. Blocks until the entire message is queued
+        for sending, or until `zmq_term` is called on the `zmq_context`
+        associated with `socket`. If the context is terminated,
+        `make_error_code(ETERM)` is returned.
+
+        \note This will automatically retry on `EINTR`, so exiting on
+            interrupts requires context termination.
+        \note If non-blocking behavior is requested on `socket` or by `flags`,
+            then `net::zmq::make_error_code(EAGAIN)` will be returned if this
+            would block.
+
+        \param payload sent as one message on `socket`.
+        \param socket Handle created with `zmq_socket`.
+        \param flags See `zmq_send` for possible flags.
+        \return `success()` if sent, otherwise ZMQ error. */
+    expect<void> send(epee::span<const std::uint8_t> payload, void* socket, int flags = 0) noexcept;
+} // zmq
+} // net