conan入门(二十):封装只包含头文件(header_only)的库示例

10km

发布于 2022-04-13 12:33:02

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发布于 2022-04-13 12:33:02

文章被收录于专栏：10km的专栏

conan: 封装只包含头文件(header_only)的库示例

有的C/C++项目只包含头文件，不需要编译，对于这种情况如何封装为Conan的包呢？

Conan官方文档《Package scaffolding for conan new command》给出了样例

我就有这样一个项目 common_source_cpp收集了工作中常用的代码，以C/C++头文件形式为主,本文就以common_source_cpp为例说明如何实现conanfile.py将它封装为一个不需要编译只有头文件的Conan包。

conanfile.py

conanfile.py 码云地址: https://gitee.com/l0km/common_source_cpp/blob/master/conanfile.py

from conans import ConanFile, tools

class CommonSourceCppConan(ConanFile):
    name = "common_source_cpp"
    version = "0.0.0-DEV"
    settings = "os", "compiler", "build_type", "arch"
    description = "C/C++/C++11公用代码"
    url = "https://gitee.com/l0km/common_source_cpp"
    license = "BSD-2-Clause"
    author = "guyadong 10km0811@sohu.com"
    topics = ("C", "C++", "C++11", "common")

    settings = "os", "arch", "compiler", "build_type"

    exports_sources = "*.h", "*.cpp", "*.hpp", "*.hh", "*.c", "LICENSE"

    def package(self):
        self.copy("*.h", dst="include")
        self.copy("*.cpp", dst="include")
        self.copy("*.hpp", dst="include")
        self.copy("*.hh", dst="include")
        self.copy("*.c", dst="include")
        self.copy("LICENSE", dst="include")

    def package_id(self):
        # 重要：指定项目只有头文件
        self.info.header_only()

    def package_info(self):
        if self.settings.compiler == "Visual Studio":
            self.cpp_info.includedirs.append("include/dirent")

conanfile_master.py

如果需要项目的最新版本则实现如下

conanfile_master.py 码云地址: https://gitee.com/l0km/common_source_cpp/blob/master/conanfile_master.py

from conans import ConanFile, tools

class CommonSourceCppConanConan(ConanFile):
    name = "common_source_cpp"
    version = "master"
    settings = "os", "compiler", "build_type", "arch"
    description = "C/C++/C++11公用代码"
    url = "https://gitee.com/l0km/common_source_cpp"
    license = "BSD-2-Clause"
    author = "guyadong 10km0811@sohu.com"
    topics = ("C", "C++", "C++11", "common")

    settings = "os", "arch", "compiler", "build_type"

    def export(self):
        self.copy("conanfile.py",src="conanfile_master.py")
        
    def source(self):
        # 从远端仓库下载指定分支代码
        self.run("git clone -b " + self.version + " " + self.url + ".git")
        # git = tools.Git(folder=self.name)
        # git.clone(self.url + ".git")
        # git.checkout(self.version)

    def package(self):
        # 确保当前仓库与远程仓库同步
        self.run("cd common_source_cpp && git checkout " + self.version + " && git pull")
        self.copy("*.h", dst="include", src="common_source_cpp")
        self.copy("*.cpp", dst="include", src="common_source_cpp")
        self.copy("*.hpp", dst="include", src="common_source_cpp")
        self.copy("*.hh", dst="include", src="common_source_cpp")
        self.copy("*.c", dst="include", src="common_source_cpp")
        self.copy("LICENSE", dst="include", src="common_source_cpp")

    def package_id(self):
        self.info.header_only()

    def package_info(self):
        if self.settings.compiler == "Visual Studio":
            self.cpp_info.includedirs.append("include/dirent")

conan create

有了上面的conanfile.py，就可以执行conan create 命令将cpp_redis生成到本地的conan仓库了

$ conan create .
Exporting package recipe
common_source_cpp/0.0.0-DEV exports_sources: Copied 43 '.h' files
common_source_cpp/0.0.0-DEV exports_sources: Copied 8 '.cpp' files
common_source_cpp/0.0.0-DEV exports_sources: Copied 11 '.hpp' files
common_source_cpp/0.0.0-DEV exports_sources: Copied 1 '.hh' file: uri.hh
common_source_cpp/0.0.0-DEV exports_sources: Copied 2 '.c' files: debug_printf.c, if_utilits_c.c
common_source_cpp/0.0.0-DEV exports_sources: Copied 1 file: LICENSE
common_source_cpp/0.0.0-DEV: The stored package has not changed
common_source_cpp/0.0.0-DEV: Exported revision: 50a7e6024f11c1e9b6bbab7e45c4253e
Configuration:
[settings]
arch=x86_64
arch_build=x86_64
build_type=Release
compiler=Visual Studio
compiler.runtime=MD
compiler.version=14
os=Windows
os_build=Windows
[options]
[build_requires]
[env]

common_source_cpp/0.0.0-DEV: Forced build from source
Installing package: common_source_cpp/0.0.0-DEV
Requirements
    common_source_cpp/0.0.0-DEV from local cache - Cache
Packages
    common_source_cpp/0.0.0-DEV:5ab84d6acfe1f23c4fae0ab88f26e3a396351ac9 - Build

Installing (downloading, building) binaries...
common_source_cpp/0.0.0-DEV: Copying sources to build folder
。。。
common_source_cpp/0.0.0-DEV: Calling package()
common_source_cpp/0.0.0-DEV package(): Packaged 43 '.h' files
common_source_cpp/0.0.0-DEV package(): Packaged 11 '.hpp' files
common_source_cpp/0.0.0-DEV package(): Packaged 2 '.c' files: debug_printf.c, if_utilits_c.c
common_source_cpp/0.0.0-DEV package(): Packaged 8 '.cpp' files
common_source_cpp/0.0.0-DEV package(): Packaged 1 file: LICENSE
common_source_cpp/0.0.0-DEV package(): Packaged 1 '.hh' file: uri.hh
common_source_cpp/0.0.0-DEV: Package '5ab84d6acfe1f23c4fae0ab88f26e3a396351ac9' created
common_source_cpp/0.0.0-DEV: Created package revision 6b32a82748a8366bb24b66daef5296df
common_source_cpp/0.0.0-DEV: WARN: This conanfile has no build step

conan create .根据配置文件 (同级文件夹下的conanfile.py) 构建二进制包 conan create 命令行用法参见Conan官方文档《conan create》

执行 conann create指定conanfile_master.py则会从远端仓库下载最新的maste分支代码

$ conan create conanfile_master.py
Exporting package recipe
common_source_cpp/master: Calling export()
common_source_cpp/master: The stored package has not changed
common_source_cpp/master: Exported revision: 4115d7716d69dce3edff00b6da3560ab
Configuration:
[settings]
arch=x86_64
arch_build=x86_64
build_type=Release
compiler=Visual Studio
compiler.runtime=MD
compiler.version=14
os=Windows
os_build=Windows
[options]
[build_requires]
[env]

common_source_cpp/master: Forced build from source
Installing package: common_source_cpp/master
Requirements
    common_source_cpp/master from local cache - Cache
Packages
    common_source_cpp/master:5ab84d6acfe1f23c4fae0ab88f26e3a396351ac9 - Build

Installing (downloading, building) binaries...
common_source_cpp/master: Copying sources to build folder
common_source_cpp/master: Building your package in 
。。。
common_source_cpp/master: Calling package()
Already on 'master'
Your branch is up to date with 'origin/master'.
Already up to date.
common_source_cpp/master package(): Packaged 43 '.h' files
common_source_cpp/master package(): Packaged 11 '.hpp' files
common_source_cpp/master package(): Packaged 2 '.c' files: debug_printf.c, if_utilits_c.c
common_source_cpp/master package(): Packaged 8 '.cpp' files
common_source_cpp/master package(): Packaged 1 file: LICENSE
common_source_cpp/master package(): Packaged 1 '.hh' file: uri.hh
common_source_cpp/master: Package '5ab84d6acfe1f23c4fae0ab88f26e3a396351ac9' created
common_source_cpp/master: Created package revision 778c04901c633169b88ac94242cc152f
common_source_cpp/master: WARN: This conanfile has no build step

执行conan search会显示本地仓库二进制包的信息

$ conan search common_source_cpp/0.0.0-DEV@
Existing packages for recipe common_source_cpp/0.0.0-DEV:

    Package_ID: 5ab84d6acfe1f23c4fae0ab88f26e3a396351ac9
        Outdated from recipe: False

$ conan search common_source_cpp/master@
Existing packages for recipe common_source_cpp/master:

    Package_ID: 5ab84d6acfe1f23c4fae0ab88f26e3a396351ac9
        Outdated from recipe: False

conan upload

执行conan upload上传到私有制品库了：

conan upload common_source_cpp/0.0.0-DEV  -r ${repo} -all
# ${repo}为私有制品库的名字

–all 指定上传所有内容(配置文件conanfile.py,源码和打包的文件–package),如果不指定些选项，只上传除package之外的所有文件

执行conan upload上传到私有制品库了：

conan upload common_source_cpp/master  -r ${repo} 
# ${repo}为私有制品库的名字

注意：因为我们需要common_source_cpp/master保持与远程端同步的最新代码，所以这里没有使用–all 指定上传所有内容(配置文件conanfile.py,源码和package),只上传了conanfile.py，引用该项目时执行conan install common_source_cpp/master@ --build common_source_cpp会自动从远程仓库克隆代码在本地仓库生成package 关于 conan upload命令的详细说明参见Conan官方文档:《conan upload》