编译iOS上的libevent库
前言：昨天正好在Android上把libevent跑通了，就是用了之前一篇文章中提到的流程方案。今天索性把iOS上的libevent也编译了下。iOS上的交叉编译比NDK的要顺利许多，大概是找到了对应比较好的文章做参考吧。
准备工作
有OS X系统，我这里装的是10.8 64-bit。
Xcode是4.5.2，对应的SDK版本为6.0
下载libevent版本，可是是官方最新的2.0.21或者是git上对应的那个for Android的版本，都可以。git上那份我记得是2.0.20的，差距应该不大。
下载openssl库，目前最新是1.0.1e的版本
编译
生成configure文件
如果是官方的2.0.21-stable版本，则文件中已经有configure文件生成了，这步骤可以跳过。如果没有，则执行目录下的autogen.sh脚本，生成configure。其间可能需要安装autoconf、automake和libtool等工具，直接下载对应的源码，然后编译安装即可。至于如何安装，我给个命令列表，有需要的看下即可：
./configure && make
sudo make install经过以上的步骤，libevent源码目录下应该已经有configure等文件生成了。
编辑build_libevent.sh脚本
接下来就是编写编译脚本了，实际上就是使用configure工具，指定对应的生成目录。这里可以给一个洋葱浏览器的开源脚本，很强大，帮你直接在MAC OS X上下载编译libevent库。
https://github.com/mtigas/iOS-OnionBrowser/blob/master/build-libevent.sh
我的配置基本都是抄里面的，当然，如果直接用也没什么问题，他会帮你下载libevent和openssl库，然后编译，生成对应的静态库文件。值得一提的是，Mac上可以直接用lipo命令把多份静态库整合到一起，比如i386、armv7和armv7s三种CPU架构的静态库整合成一份，这实在让人很兴奋。如果Android上也能这么搞，那该多好，当然我还没去查阅过资料，不知道linux上是否支持lipo。
编译libevent的库有个要注意的地方（这个坑了我很久），就是如果需要openssl支持，那要先编译openssl库，否则是不会带libevent_openssl.a这个静态库的。
下面我索性把那两个bash脚本放上来，首先是libevent的
#!/bin/bash
# Builds libevent for all three current iPhone targets: iPhoneSimulator-i386,
# iPhoneOS-armv6, iPhoneOS-armv7.
#
# Copyright 2012 Mike Tigas
#
# Based on work by Felix Schulze on 16.12.10.
# Copyright 2010 Felix Schulze. All rights reserved.
#
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at
#
# http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
# limitations under the License.
#
###########################################################################
# Choose your libevent version and your currently-installed iOS SDK version:
#
VERSION="2.0.21-stable"
SDKVERSION="6.1"
#
#
###########################################################################
#
# Don't change anything under this line!
#
###########################################################################
# No need to change this since xcode build will only compile in the
# necessary bits from the libraries we create
ARCHS="i386 armv7 armv7s"
DEVELOPER=`xcode-select -print-path`
cd "`dirname \"$0\"`"
REPOROOT=$(pwd)
# Where we'll end up storing things in the end
OUTPUTDIR="${REPOROOT}/dependencies"
mkdir -p ${OUTPUTDIR}/include
mkdir -p ${OUTPUTDIR}/lib
BUILDDIR="${REPOROOT}/build"
# where we will keep our sources and build from.
SRCDIR="${BUILDDIR}/src"
mkdir -p $SRCDIR
# where we will store intermediary builds
INTERDIR="${BUILDDIR}/built"
mkdir -p $INTERDIR
########################################
cd $SRCDIR
# Exit the script if an error happens
set -e
if [ ! -e "${SRCDIR}/libevent-${VERSION}.tar.gz" ]; then
echo "Downloading libevent-${VERSION}.tar.gz"
curl -LO https://github.com/downloads/libevent/libevent/libevent-${VERSION}.tar.gz
else
echo "Using libevent-${VERSION}.tar.gz"
fi
tar zxf libevent-${VERSION}.tar.gz -C $SRCDIR
cd "${SRCDIR}/libevent-${VERSION}"
set +e # don't bail out of bash script if ccache doesn't exist
CCACHE=`which ccache`
if [ $? == "0" ]; then
echo "Building with ccache: $CCACHE"
CCACHE="${CCACHE} "
else
echo "Building without ccache"
CCACHE=""
fi
set -e # back to regular "bail out on error" mode
for ARCH in ${ARCHS}
do
if [ "${ARCH}" == "i386" ];
then
PLATFORM="iPhoneSimulator"
EXTRA_CONFIG=""
else
PLATFORM="iPhoneOS"
EXTRA_CONFIG="--host=arm-apple-darwin11"
fi
mkdir -p "${INTERDIR}/${PLATFORM}${SDKVERSION}-${ARCH}.sdk"
./configure --disable-shared --enable-static --disable-debug-mode ${EXTRA_CONFIG} \
--prefix="${INTERDIR}/${PLATFORM}${SDKVERSION}-${ARCH}.sdk" \
CC="${CCACHE}${DEVELOPER}/Platforms/${PLATFORM}.platform/Developer/usr/bin/gcc -arch ${ARCH}" \
LDFLAGS="$LDFLAGS -L${OUTPUTDIR}/lib" \
CFLAGS="$CFLAGS -I${OUTPUTDIR}/include -isysroot ${DEVELOPER}/Platforms/${PLATFORM}.platform/Developer/SDKs/${PLATFORM}${SDKVERSION}.sdk" \
CPPFLAGS="$CPPFLAGS -I${OUTPUTDIR}/include -isysroot ${DEVELOPER}/Platforms/${PLATFORM}.platform/Developer/SDKs/${PLATFORM}${SDKVERSION}.sdk"
# Build the application and install it to the fake SDK intermediary dir
# we have set up. Make sure to clean up afterward because we will re-use
# this source tree to cross-compile other targets.
make -j4
make install
make clean
done
########################################
echo "Build library..."
# These are the libs that comprise libevent. `libevent_openssl` and `libevent_pthreads`
# may not be compiled if those dependencies aren't available.
OUTPUT_LIBS="libevent.a libevent_core.a libevent_extra.a libevent_openssl.a libevent_pthreads.a"
for OUTPUT_LIB in ${OUTPUT_LIBS}; do
INPUT_LIBS=""
for ARCH in ${ARCHS}; do
if [ "${ARCH}" == "i386" ];
then
PLATFORM="iPhoneSimulator"
else
PLATFORM="iPhoneOS"
fi
INPUT_ARCH_LIB="${INTERDIR}/${PLATFORM}${SDKVERSION}-${ARCH}.sdk/lib/${OUTPUT_LIB}"
if [ -e $INPUT_ARCH_LIB ]; then
INPUT_LIBS="${INPUT_LIBS} ${INPUT_ARCH_LIB}"
fi
done
# Combine the three architectures into a universal library.
if [ -n "$INPUT_LIBS" ]; then
lipo -create $INPUT_LIBS \
-output "${OUTPUTDIR}/lib/${OUTPUT_LIB}"
else
echo "$OUTPUT_LIB does not exist, skipping (are the dependencies installed?)"
fi
done
for ARCH in ${ARCHS}; do
if [ "${ARCH}" == "i386" ];
then
PLATFORM="iPhoneSimulator"
else
PLATFORM="iPhoneOS"
fi
cp -R ${INTERDIR}/${PLATFORM}${SDKVERSION}-${ARCH}.sdk/include/* ${OUTPUTDIR}/include/
if [ $? == "0" ]; then
# We only need to copy the headers over once. (So break out of forloop
# once we get first success.)
break
fi
done
####################
echo "Building done."
echo "Cleaning up..."
rm -fr ${INTERDIR}
rm -fr "${SRCDIR}/libevent-${VERSION}"
echo "Done." 这里要注意的地方有两个：
- 最上面的库的版本和对应SDK的版本了（执行openssl编译的时候也一样），请根据你的需要去设定，特别是SDK的版本，默认这里是6.1的，我是用Xcode4.5.2，翻看了目录里面，只有6.0的SDK，所以这里要根据你自己的Xcode中SDK的版本设定，否则会找不到编译器
- 设定DEVELOPER变量的地方要注意，我的机器上通过xcode-select -print-path得到的路径是/Volumne/Xcode.app/Contents/Developer，但其实我是放在桌面的，如果这个目录不对可能会同样找不到编译器，这里可以写绝对路径（不要用相对路径，会报错的）
直接在你的目录下运行这个bash即可。
如果没有openssl的库，经过上面的编译，libevent_openssl.a 这个库是没有的，在configure过程中就会检测到openssl无效，Makefile中会把对应的代码注释掉。所以如果需要openssl的支持，那就要先运行build_ssl.sh这个脚本，同样，注意事项和build_libevent.sh一致。其实这两个脚本放到同一个libevent目录下即可。
#!/bin/bash
# Builds openssl for all three current iPhone targets: iPhoneSimulator-i386,
# iPhoneOS-armv6, iPhoneOS-armv7.
#
# Copyright 2012 Mike Tigas
#
# Based on work by Felix Schulze on 16.12.10.
# Copyright 2010 Felix Schulze. All rights reserved.
#
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at
#
# http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
# limitations under the License.
#
###########################################################################
# Choose your openssl version and your currently-installed iOS SDK version:
#
VERSION="1.0.1e"
SDKVERSION="6.1"
#
#
###########################################################################
#
# Don't change anything under this line!
#
###########################################################################
# No need to change this since xcode build will only compile in the
# necessary bits from the libraries we create
ARCHS="i386 armv7 armv7s"
DEVELOPER=`xcode-select -print-path`
cd "`dirname \"$0\"`"
REPOROOT=$(pwd)
# Where we'll end up storing things in the end
OUTPUTDIR="${REPOROOT}/dependencies"
mkdir -p ${OUTPUTDIR}/include
mkdir -p ${OUTPUTDIR}/lib
BUILDDIR="${REPOROOT}/build"
# where we will keep our sources and build from.
SRCDIR="${BUILDDIR}/src"
mkdir -p $SRCDIR
# where we will store intermediary builds
INTERDIR="${BUILDDIR}/built"
mkdir -p $INTERDIR
########################################
cd $SRCDIR
# Exit the script if an error happens
set -e
if [ ! -e "${SRCDIR}/openssl-${VERSION}.tar.gz" ]; then
echo "Downloading openssl-${VERSION}.tar.gz"
curl -O http://www.openssl.org/source/openssl-${VERSION}.tar.gz
else
echo "Using openssl-${VERSION}.tar.gz"
fi
tar zxf openssl-${VERSION}.tar.gz -C $SRCDIR
cd "${SRCDIR}/openssl-${VERSION}"
set +e # don't bail out of bash script if ccache doesn't exist
CCACHE=`which ccache`
if [ $? == "0" ]; then
echo "Building with ccache: $CCACHE"
CCACHE="${CCACHE} "
else
echo "Building without ccache"
CCACHE=""
fi
set -e # back to regular "bail out on error" mode
for ARCH in ${ARCHS}
do
if [ "${ARCH}" == "i386" ];
then
PLATFORM="iPhoneSimulator"
else
sed -ie "s!static volatile sig_atomic_t intr_signal;!static volatile intr_signal;!" "crypto/ui/ui_openssl.c"
PLATFORM="iPhoneOS"
fi
echo "Building openssl-${VERSION} for ${PLATFORM} ${SDKVERSION} ${ARCH}"
echo "Please stand by..."
mkdir -p "${INTERDIR}/${PLATFORM}${SDKVERSION}-${ARCH}.sdk"
#LOG="${INTERDIR}/${PLATFORM}${SDKVERSION}-${ARCH}.sdk/build-openssl-${VERSION}.log"
export CC="${CCACHE}${DEVELOPER}/Platforms/${PLATFORM}.platform/Developer/usr/bin/gcc -arch ${ARCH}"
./configure BSD-generic32 \
--openssldir="${INTERDIR}/${PLATFORM}${SDKVERSION}-${ARCH}.sdk" #> "${LOG}" 2>&1
# add -isysroot to configure-generated CFLAGS
sed -ie "s!^CFLAG=!CFLAG=-isysroot ${DEVELOPER}/Platforms/${PLATFORM}.platform/Developer/SDKs/${PLATFORM}${SDKVERSION}.sdk !" "Makefile"
# Build the application and install it to the fake SDK intermediary dir
# we have set up. Make sure to clean up afterward because we will re-use
# this source tree to cross-compile other targets.
make #>> "${LOG}" 2>&1
make install #>> "${LOG}" 2>&1
make clean #>> "${LOG}" 2>&1
done
########################################
echo "Build library..."
OUTPUT_LIBS="libssl.a libcrypto.a"
for OUTPUT_LIB in ${OUTPUT_LIBS}; do
INPUT_LIBS=""
for ARCH in ${ARCHS}; do
if [ "${ARCH}" == "i386" ];
then
PLATFORM="iPhoneSimulator"
else
PLATFORM="iPhoneOS"
fi
INPUT_ARCH_LIB="${INTERDIR}/${PLATFORM}${SDKVERSION}-${ARCH}.sdk/lib/${OUTPUT_LIB}"
if [ -e $INPUT_ARCH_LIB ]; then
INPUT_LIBS="${INPUT_LIBS} ${INPUT_ARCH_LIB}"
fi
done
# Combine the three architectures into a universal library.
if [ -n "$INPUT_LIBS" ]; then
lipo -create $INPUT_LIBS \
-output "${OUTPUTDIR}/lib/${OUTPUT_LIB}"
else
echo "$OUTPUT_LIB does not exist, skipping (are the dependencies installed?)"
fi
done
for ARCH in ${ARCHS}; do
if [ "${ARCH}" == "i386" ];
then
PLATFORM="iPhoneSimulator"
else
PLATFORM="iPhoneOS"
fi
cp -R ${INTERDIR}/${PLATFORM}${SDKVERSION}-${ARCH}.sdk/include/* ${OUTPUTDIR}/include/
if [ $? == "0" ]; then
# We only need to copy the headers over once. (So break out of forloop
# once we get first success.)
break
fi
done
echo "Building done."
echo "Cleaning up..."
rm -fr ${INTERDIR}
rm -fr "${SRCDIR}/openssl-${VERSION}"
echo "Done." 再次感谢洋葱浏览器的作者，好强大的脚本啊，呵呵。
编译完成后，对应的库文件存放在dependencies目录的lib目录中，外层的include是对应调用库时需要用到的头文件。好了，iOS上的libevent库就这样搞定了。
顺便丢个编译好的库文件： 下载