esp_timer: added C++ wrapper for esp_timer

Closes IDF-1074

examples/cxx/experimental/experimental_cpp_component/esp_timer_cxx.cpp

@@ -0,0 +1,60 @@
+// Copyright 2020 Espressif Systems (Shanghai) PTE LTD
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//         http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+#ifdef __cpp_exceptions
+
+#include <functional>
+#include "esp_timer_cxx.hpp"
+#include "esp_exception.hpp"
+
+using namespace std;
+
+namespace idf {
+
+namespace esp_timer {
+
+ESPTimer::ESPTimer(function<void()> timeout_cb, const string &timer_name)
+    : timeout_cb(timeout_cb), name(timer_name)
+{
+    if (timeout_cb == nullptr) {
+        throw ESPException(ESP_ERR_INVALID_ARG);
+    }
+
+    esp_timer_create_args_t timer_args = {};
+    timer_args.callback = esp_timer_cb;
+    timer_args.arg = this;
+    timer_args.dispatch_method = ESP_TIMER_TASK;
+    timer_args.name = name.c_str();
+
+    CHECK_THROW(esp_timer_create(&timer_args, &timer_handle));
+}
+
+ESPTimer::~ESPTimer()
+{
+    // Ignore potential ESP_ERR_INVALID_STATE here to not throw exception.
+    esp_timer_stop(timer_handle);
+    esp_timer_delete(timer_handle);
+}
+
+void ESPTimer::esp_timer_cb(void *arg)
+{
+    ESPTimer *timer = static_cast<ESPTimer*>(arg);
+    timer->timeout_cb();
+}
+
+} // esp_timer
+
+} // idf
+
+#endif // __cpp_exceptions