From c3a23379ea80de93321a89ea63d939c6c66b9a0d Mon Sep 17 00:00:00 2001
From: Gemfield <gemfield@civilnet.cn>
Date: Wed, 20 Feb 2019 06:59:31 -0800
Subject: [PATCH] add install step and docs for Android build (#17298)

Summary:
This commit did below enhancements:
1, add doc for build_android.sh;
2, add install step for build_android.sh, thus the headers and libraries can be collected together for further usage conveniently;
3, change the default INSTALL_PREFIX from $PYTORCH_ROOT/install to $PYTORCH_ROOT/build_android/install to make the project directory clean.
Pull Request resolved: https://github.com/pytorch/pytorch/pull/17298

Differential Revision: D14149709

Pulled By: soumith

fbshipit-source-id: a3a38cb41f26377e21aa89e49e57e8f21c9c1a39
---
 scripts/README.md        | 23 +++++++++++++++++++++++
 scripts/build_android.sh | 19 ++++++++++++++-----
 2 files changed, 37 insertions(+), 5 deletions(-)
 create mode 100644 scripts/README.md

diff --git a/scripts/README.md b/scripts/README.md
new file mode 100644
index 0000000..102f049
--- /dev/null
+++ b/scripts/README.md
@@ -0,0 +1,23 @@
+This directory contains the usful tools.
+
+
+## build_android.sh
+This script is to build PyTorch/Caffe2 library for Android. Take following steps to start the build:
+
+- set ANDROID_NDK to the location of ndk
+
+```bash
+export ANDROID_NDK=YOUR_NDK_PATH
+```
+
+- run build_android.sh
+```bash
+#in your PyTorch root directory
+bash scripts/build_android.sh
+```
+If succeeded, the libraries and headers would be generated to build_android/install directory. You can then copy these files from build_android/install to your Android project for further usage. 
+
+You can also override the cmake flags via command line, e.g., following command will also compile the executable binary files:
+```bash
+bash scripts/build_android.sh -DBUILD_BINARY=ON
+```
diff --git a/scripts/build_android.sh b/scripts/build_android.sh
index eacba45..0cc4948 100755
--- a/scripts/build_android.sh
+++ b/scripts/build_android.sh
@@ -21,8 +21,12 @@
 
 set -e
 
-CAFFE2_ROOT="$( cd "$(dirname "$0")"/.. ; pwd -P)"
+# Android specific flags
+ANDROID_ABI="armeabi-v7a with NEON"
+ANDROID_NATIVE_API_LEVEL="21"
+echo "Build with ANDROID_ABI[$ANDROID_ABI], ANDROID_NATIVE_API_LEVEL[$ANDROID_NATIVE_API_LEVEL]"
 
+CAFFE2_ROOT="$( cd "$(dirname "$0")"/.. ; pwd -P)"
 if [ -z "$ANDROID_NDK" ]; then
   echo "ANDROID_NDK not set; please set it to the Android NDK directory"
   exit 1
@@ -43,6 +47,7 @@ $CAFFE2_ROOT/scripts/build_host_protoc.sh
 
 # Now, actually build the Android target.
 BUILD_ROOT=${BUILD_ROOT:-"$CAFFE2_ROOT/build_android"}
+INSTALL_PREFIX=${BUILD_ROOT}/install
 mkdir -p $BUILD_ROOT
 cd $BUILD_ROOT
 
@@ -74,7 +79,6 @@ CMAKE_ARGS+=("-DUSE_LMDB=OFF")
 CMAKE_ARGS+=("-DUSE_LEVELDB=OFF")
 CMAKE_ARGS+=("-DUSE_MPI=OFF")
 CMAKE_ARGS+=("-DUSE_OPENMP=OFF")
-
 # Only toggle if VERBOSE=1
 if [ "${VERBOSE:-}" == '1' ]; then
   CMAKE_ARGS+=("-DCMAKE_VERBOSE_MAKEFILE=1")
@@ -82,15 +86,15 @@ fi
 
 # Android specific flags
 CMAKE_ARGS+=("-DANDROID_NDK=$ANDROID_NDK")
-CMAKE_ARGS+=("-DANDROID_ABI=armeabi-v7a with NEON")
-CMAKE_ARGS+=("-DANDROID_NATIVE_API_LEVEL=21")
+CMAKE_ARGS+=("-DANDROID_ABI=$ANDROID_ABI")
+CMAKE_ARGS+=("-DANDROID_NATIVE_API_LEVEL=$ANDROID_NATIVE_API_LEVEL")
 CMAKE_ARGS+=("-DANDROID_CPP_FEATURES=rtti exceptions")
 
 # Use-specified CMake arguments go last to allow overridding defaults
 CMAKE_ARGS+=($@)
 
 cmake "$CAFFE2_ROOT" \
-    -DCMAKE_INSTALL_PREFIX=../install \
+    -DCMAKE_INSTALL_PREFIX=$INSTALL_PREFIX \
     -DCMAKE_BUILD_TYPE=Release \
     "${CMAKE_ARGS[@]}"
 
@@ -103,3 +107,8 @@ if [ -z "$MAX_JOBS" ]; then
   fi
 fi
 cmake --build . -- "-j${MAX_JOBS}"
+
+# copy headers and libs to install directory
+echo "Will install headers and libs to $INSTALL_PREFIX for further Android project usage."
+make install
+echo "Installation completed, now you can copy the headers/libs from $INSTALL_PREFIX to your Android project directory."
-- 
2.7.4