在add_custom_command

时间:2018-08-23 14:53:10

标签: cmake add-custom-command

我有一个包含一堆数据的文件。我想将其转换为C ++字符串文字,因为我需要将此数据编译为二进制文件-无法从磁盘读取它。

执行此操作的一种方法是仅生成一个C ++源文件,该文件声明具有已知名称的字符串文字。 CMake代码很简单,即使有些糟糕:

function(make_literal_from_file dest_file source_file literal_name)              
    add_custom_command(                                                          
        OUTPUT ${dest_file}                                                      
        COMMAND printf \'char const* ${literal_name} = R\"\#\(\' > ${dest_file}  
        COMMAND cat ${source_file} >> ${dest_file}                               
        COMMAND printf \'\)\#\"\;\' >> ${dest_file}                              
        DEPENDS ${source_file})                                                  
endfunction()

这有效并且可以完成我想要的操作(printf是必需的,以避免在原始字符串介绍器之后出现新行)。但是,这里发生的大量转义使得很难看到正在发生的事情。有没有一种方法可以编写此函数使其真正可读?


请注意,此处不能使用file(READ ...) / configure_file(...)组合,因为source_file可能是CMake在构建时生成的,因此在配置时可能不存在。 / p>

1 个答案:

答案 0 :(得分:2)

我建议编写脚本来执行此操作。您可以用CMake编写它,但是我个人更喜欢更好的语言,例如Python:

# Untested, just to show roughly how to do it
import sys

dest_file, source_file, literal_name = sys.argv[1:]

with open(dest_file) as dest, open(source_file) as source:
    literal_contents = source.read()
    dest.write(f'char const* {literal_name} = R"({literal_contents})";\n')

对应的CMake代码:

# String interpolation came in Python 3.6, thus the requirement on 3.6.
# If using CMake < 3.12, use find_package(PythonInterp) instead.
find_package(Python3 3.6 COMPONENTS Interpreter)

# Make sure this resolves correctly. ${CMAKE_CURRENT_LIST_DIR} is helpful;
# it's the directory containing the current file (this cmake file)
set(make_literal_from_file_script "path/to/make_literal_from_file.py")

function(make_literal_from_file dest_file source_file literal_name)              
    add_custom_command(                                                          
        OUTPUT "${dest_file}"
        COMMAND 
            "${Python3_EXECUTABLE}" "${make_literal_from_file_script}"
            "${dest_file}"
            "${source_file}"
            "${literal_name}"
        DEPENDS "${source_file}")                                                  
endfunction()

如果您不希望依赖于Python,则可以使用C ++(仅显示CMake代码):

add_executable(make_literal_from_file_exe
    path/to/cpp/file.cpp
)

function(make_literal_from_file dest_file source_file literal_name)              
    add_custom_command(                                                          
        OUTPUT "${dest_file}"
        COMMAND 
            make_literal_from_file_exe
            "${dest_file}"
            "${source_file}"
            "${literal_name}"
        DEPENDS "${source_file}")
endfunction()