demo of downloading and building an external library

Author: igrr

idf_component_examples/Hello_world/.gitignore

@@ -0,0 +1,7 @@
+arduino_libs
+build
+.cache
+managed_components
+dependencies.lock
+sdkconfig
+sdkconfig.old

idf_component_examples/Hello_world/CMakeLists.txt

@@ -1,8 +1,14 @@
-# For more information about build system see
-# https://docs.espressif.com/projects/esp-idf/en/latest/api-guides/build-system.html
-# The following five lines of boilerplate have to be in your project's
-# CMakeLists in this exact order for cmake to work correctly
-cmake_minimum_required(VERSION 3.16)
+cmake_minimum_required(VERSION 3.17)
 
 include($ENV{IDF_PATH}/tools/cmake/project.cmake)
-project(main)
+project(hello_world)
+
+# Download BufferUtils library
+include(FetchContent)
+FetchContent_Populate(BufferUtils
+    URL https://github.com/bakercp/BufferUtils/archive/refs/tags/3.0.0.zip
+    SOURCE_DIR ${CMAKE_CURRENT_LIST_DIR}/arduino_libs/BufferUtils
+)
+
+# Add Arduino libraries to the project
+add_arduino_libraries(${CMAKE_CURRENT_LIST_DIR}/arduino_libs)

idf_component_examples/Hello_world/main/main.cpp

@@ -1,7 +1,12 @@
 #include "Arduino.h"
+#include "CircularBuffer.h"
 
 void setup() {
   Serial.begin(115200);
+
+  uint8_t data[10];
+  CircularBuffer buffer(data, sizeof(data));
+  buffer.put(1);
 }
 
 void loop() {

project_include.cmake

@@ -1,15 +1,23 @@
 function(add_arduino_libraries libs_dir)
     # Construct the absolute path for libs_dir relative to the CMake project root
-    set(libs_dir_abs "${CMAKE_SOURCE_DIR}/${libs_dir}")
-    
+    if (IS_ABSOLUTE "${libs_dir}")
+        set(libs_dir_abs "${libs_dir}")
+    else()
+        set(libs_dir_abs "${CMAKE_SOURCE_DIR}/${libs_dir}")
+    endif()
+
     # Verify if libs_dir_abs is a valid directory
     if(NOT IS_DIRECTORY "${libs_dir_abs}")
         message(FATAL_ERROR "The specified libs_dir (${libs_dir_abs}) is not a valid directory.")
         return()  # Stop processing if the directory is invalid
     endif()
 
-    idf_component_get_property(arduino_esp32_lib arduino COMPONENT_LIB)
-    
+    # Get the name of the arduino component. It is the same as the name of the current directory.
+    get_filename_component(arduino_component_name ${CMAKE_CURRENT_FUNCTION_LIST_DIR} NAME)
+    message(STATUS "Adding Arduino libraries to ${arduino_component_name} component")
+
+    idf_component_get_property(arduino_esp32_lib ${arduino_component_name} COMPONENT_LIB)
+
     # Loop through each folder in the libs_dir
     file(GLOB children RELATIVE ${libs_dir_abs} ${libs_dir_abs}/*)
     foreach(child ${children})