Esp32 add multi directory custom component

Preface

stay esp32 In development , In general, it is vscode. Didn't like keil mdk And so on , I'm not familiar with it cmake People are not very friendly . The author also referred to cmake Official documents and esp32 Development Manual , Find a very effective and simple CmakeList.txt The way of writing .

esp32 Project directory

esp The official recommended directory format is two folders , One is main Folder , One is components Folder , The names of these two folders are not recommended to be changed , These two are esp32 The development environment defaults to main Module and components modular .

esp32 Adopted cmake Compiler tools . When you add a new file, you need to write it yourself cmakelist.txt. The main point here is components Folder .

components Folder

components Each subfolder under the folder esp-idf The environment will think of it as a module . Like in the picture above a,lvgl,sda It's all a module . You need to create a new one under the root directory of each sub module CMakeLists.txt. For example, above a There is one in the catalog CMakeLists.txt, Just this one .mk Documents are unnecessary .a Only put the source code you need in the subdirectory of , No more CMakeLists.txt. Here's the picture ：

modular a Yes 3 The specific relationship of subdirectories is as follows ：
![ Insert picture description here ](https://img-blog.csdnimg.cn/fa38defea2d04130bb11ed56ecacffbc.png

modular a There are multiple subdirectories and the subdirectories contain .h and .c file , that Cmakelists.txt How to write it? .

file(GLOB_RECURSE SOURCES src_a/*.c src_b/*.c)

set(include_dirs 
    inc_a
    src_a
    src_a/src_c
    )
idf_component_register(SRCS ${SOURCES}
                    INCLUDE_DIRS ${include_dirs})

Above is the module a Of Cmakelists.txt The full text , Isn't that neat . Specific analysis of the project .
Let's start with the simplest set.set Is to assign a value to a variable , It's going to be inc_a src_a src_a/src_c These three folders are assigned to include_dirs. Just add the header file folder you need to use to set Just inside . adopt “$” To obtain include_dirs The value of the variable . This linux Next bash Grammar is the same .
idf_component_register This is a esp-idf Commands for adding modules , Here, you usually add source files and header files , Use them separately SRCS and INCLUDE_DIRS Keyword representation , These two keywords can be followed by multiple Variable
such as ：

idf_component_register(SRCS ${SOURCES}  "123.c"
                    INCLUDE_DIRS ${include_dirs} .  "123.h"  "inc_a"
                    ) 

• "." Represents the file in the current directory
• INCLUDE_DIRS It can be directly followed by the directory name
• SRCS It must be followed by specific documents , You cannot use a directory instead of , This tested directory is invalid , So when there are multiple in the module .c file , Follow the above method to add one by one .c file . It's too troublesome , If there's a lot of .c file , That's too much work , however esp32 There is no specific method in the development manual of . But there must be a way to make .c Files are indexed as directories .

After Baidu and a large number of tests , serviceable file This command . For a detailed explanation, see https://cmake.org/cmake/help/latest/command/file.html
file The command has two main syntax when it is used in the file system

file(GLOB <variable>
     [LIST_DIRECTORIES true|false] [RELATIVE <path>] [CONFIGURE_DEPENDS]
     [<globbing-expressions>...])
file(GLOB_RECURSE <variable> [FOLLOW_SYMLINKS]
     [LIST_DIRECTORIES true|false] [RELATIVE <path>] [CONFIGURE_DEPENDS]
     [<globbing-expressions>...])

The official interpretation of this order is , Generate a list of compliance rules , And assign the list to . It is not officially recommended that GLOB command , The command cannot read the self index of the index .

If you will file(GLOB_RECURSE SOURCES src_a/.c src_b/.c) Medium GLOB_RECURSE Change it to GLOB , Compilation will not succeed , Show that... Can't be found sumc function ,sumc Function in src_a/src_c Under the folder .

At that time, there was still a problem
When a new .c File to src_a Next time , Need to edit again Cmakelists.txt, The newly added can be recognized normally when compiling .c file , We haven't found a way to update automatically yet .

add to LVG Components

At that time, the purpose of studying this method was to keep lvgl.lvgl8.2 The directory structure of is as follows ;

among CMakeLists.txt The contents are as follows ：

file(GLOB_RECURSE SOURCES src/*.c examples/porting/*.c )

set(included_dirs src examples/porting)
idf_component_register(SRCS ${SOURCES} 
                       INCLUDE_DIRS  ${included_dirs}
                       )

adopt file This method can be very convenient to add a large number of .c Source file . The items of this experiment are shown in ：
https://download.csdn.net/download/sinat_36568888/85751343