From d7c303cacda4496eb07a31c6c272058c2a78b1f7 Mon Sep 17 00:00:00 2001
From: "rf.wu" <demonsimon@gmail.com>
Date: Mon, 14 Oct 2019 09:16:58 +0800
Subject: [PATCH] CMake: Add Android dynamic library cross compile support.

---
 CMakeLists.txt | 14 ++++++++++++++
 README.md      | 22 +++++++++++++++++++++-
 2 files changed, 35 insertions(+), 1 deletion(-)

diff --git a/CMakeLists.txt b/CMakeLists.txt
index 2c23308..682c177 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -14,6 +14,20 @@ option(YAML_CPP_BUILD_CONTRIB "Enable yaml-cpp contrib in library" ON)
 option(YAML_CPP_BUILD_TOOLS "Enable parse tools" ON)
 option(YAML_BUILD_SHARED_LIBS "Build yaml-cpp shared library" ${BUILD_SHARED_LIBS})
 
+option(YAML_BUILD_ANDROID_LIBS "Build android dynamic library" OFF)
+
+if (YAML_BUILD_ANDROID_LIBS)
+  set(YAML_BUILD_SHARED_LIBS ON)
+
+  if("${ANDROID_STL}" STREQUAL "c++_shared")
+      message(STATUS "Configuring STL libc++_shared.so for ${ANDROID_ABI}")
+      configure_file(
+          "${ANDROID_NDK}/sources/cxx-stl/llvm-libc++/libs/${ANDROID_ABI}/libc++_shared.so"
+          "${CMAKE_BINARY_DIR}/libc++_shared.so"
+          COPYONLY)
+  endif()
+endif()
+
 cmake_dependent_option(YAML_CPP_BUILD_TESTS
   "Enable yaml-cpp tests" ON
   "BUILD_TESTING;CMAKE_SOURCE_DIR STREQUAL PROJECT_SOURCE_DIR" OFF)
diff --git a/README.md b/README.md
index 92bc90e..175ae74 100644
--- a/README.md
+++ b/README.md
@@ -42,6 +42,26 @@ cmake [-G generator] [-DYAML_BUILD_SHARED_LIBS=ON|OFF] ..
 
 5. To clean up, just remove the `build` directory.
 
+## Cross Compile Dynamic Library for Android
+
+* The 3rd step above can do like this:
+
+  ```bash
+  cmake -DCMAKE_TOOLCHAIN_FILE=${NDKROOT}/build/cmake/android.toolchain.cmake -DANDROID_STL=c++_shared -DANDROID_PLATFORM=android-26 -DANDROID_ABI=x86_64 -DYAML_BUILD_ANDROID_LIBS=ON ..
+  ```
+
+  - To do cross-compiling, `ndk-bundle` OR `android-sdk` is needed. Also `NDKROOT` should be exported in your `bash` config file, just like:
+
+    ```bash
+    export NDKROOT=/path/to/Android/sdk/ndk-bundle
+    ```
+
+  - The argument `ANDROID_ABI` can be set to `arm64-v8a`, `armeabi-v7a`, `armeabi`, `x86`, `x86_64`， etc. If NOT set, the default value is `armeabi-v7a`.
+
+  - The argument `ANDROID_PLATFORM` can be set to `android-xx` OR `latest`, `xx` can be replaced to the android api number, the default value will be the minimum supported version of your `ndk-bundle`, while the value `latest` will using the maximum supported version.
+
+  - The argument  `YAML_BUILD_ANDROID_LIBS=ON` will default set `YAML_BUILD_SHARED_LIBS=ON`, and copy the `libc++_shared.so` to `build` directory from `ndk-bundle`, which is needed by `libyaml-cpp.so`.
+
 # Recent Release #
 
 [yaml-cpp 0.6.0](https://github.com/jbeder/yaml-cpp/releases/tag/yaml-cpp-0.6.0) has been released! This release requires C++11, and no longer depends on Boost.
@@ -50,6 +70,6 @@ cmake [-G generator] [-DYAML_BUILD_SHARED_LIBS=ON|OFF] ..
 
 **The old API will continue to be supported, and will still receive bugfixes!** The 0.3.x and 0.4.x versions will be old API releases, and 0.5.x and above will all be new API releases.
 
-# API Documentation 
+# API Documentation
 
 The autogenerated API reference is hosted on [CodeDocs](https://codedocs.xyz/jbeder/yaml-cpp/index.html)