mpm: Add log_buf class

This is a buffer for log messages, designed for getting log messages
from C++ back into Python.

Reviewed-By: Mark Meserve <mark.meserve@ni.com>

2 files changed, 65 insertions, 0 deletions

diff --git a/mpm/lib/types/CMakeLists.txt b/mpm/lib/types/CMakeLists.txt
index d4f52f7ed..10ce8a28c 100644
--- a/mpm/lib/types/CMakeLists.txt
+++ b/mpm/lib/types/CMakeLists.txt
@@ -1,5 +1,6 @@
 SET(TYPES_SOURCES
     ${CMAKE_CURRENT_SOURCE_DIR}/lockable.cpp
+    ${CMAKE_CURRENT_SOURCE_DIR}/log_buf.cpp
 )
 
 USRP_PERIPHS_ADD_OBJECT(types ${TYPES_SOURCES})
diff --git a/mpm/lib/types/log_buf.cpp b/mpm/lib/types/log_buf.cpp
new file mode 100644
index 000000000..d159ca6a2
--- /dev/null
+++ b/mpm/lib/types/log_buf.cpp
@@ -0,0 +1,64 @@
+//
+// Copyright 2017 Ettus Research, National Instruments Company
+//
+// SPDX-License-Identifier: GPL-3.0
+//
+
+#include <mpm/types/log_buf.hpp>
+
+using namespace mpm::types;
+
+void log_buf::post(
+    const log_level_t log_level,
+    const std::string &component,
+    const std::string &message
+) {
+    {
+        std::lock_guard<std::mutex> l(_buf_lock);
+        _buf.push_back(
+            log_message(log_level, component, message)
+        );
+    }
+
+    if (bool(_notify_callback)) {
+        _notify_callback();
+    }
+}
+
+void log_buf::set_notify_callback(
+    std::function<void(void)> callback
+) {
+    _notify_callback = callback;
+}
+
+std::tuple<log_level_t, std::string, std::string> log_buf::pop()
+{
+    std::lock_guard<std::mutex> l(_buf_lock);
+    if (_buf.empty()) {
+        return std::make_tuple(
+            log_level_t::NONE,
+            "",
+            ""
+        );
+    }
+
+    auto last_msg = _buf.front();
+    _buf.pop_front();
+    return std::make_tuple(
+        last_msg.log_level,
+        last_msg.component,
+        last_msg.message
+    );
+}
+
+log_buf::sptr log_buf::make()
+{
+    return std::make_shared<log_buf>();
+}
+
+log_buf::sptr log_buf::make_singleton()
+{
+    static auto log_sptr = log_buf::make();
+    return log_sptr;
+}
+