流程
step1 使用bsdiff生成差异包PATCH.patch
step2 在手机上合并base包和差异包，生成新版本的安装包
step3 安装新的安装包
准备
bsdiff-4.3 （用于生成差异包，合并新包）
bzip2 （bsdiff要使用到）
试验
step1 解压bsdiff4.3的压缩包
step2 修改Makefile文件，将.ifndef和.endif缩进，要么无法进行后面的操作
CFLAGS += -O3 -lbz2
PREFIX ?= /usr/localINSTALL_PROGRAM ?= ${INSTALL} -c -s -m 555
INSTALL_MAN ?= ${INSTALL} -c -m 444
all: bsdiff bspatch
bsdiff: bsdiff.c
bspatch: bspatch.c
install: ${INSTALL_PROGRAM} bsdiff bspatch ${PREFIX}/bin
.ifndef WITHOUT_MAN ${INSTALL_MAN} bsdiff.1 bspatch.1 ${PREFIX}/man/man1
.endifstep3 在该文件夹的命令行里执行make命令，会生成bsdiff和bspatch两个可执行的文件。如果是从上面的地址下载的bsdiff的话，会爆出bspatch.c:39:21: error: unknown type name 'u_char'; did you mean 'char'?这样的错误。这是由于bspatch.c中缺少了#include <sys/types.h>，加上即可。然后执行make命令。
bogon:bsdiff-4.3 Tony$ make cc -O3 -lbz2 bsdiff.c -o bsdiff cc -O3 -lbz2 bspatch.c -o bspatch
step4 准备两个同一签名的apk，old.apk和.apk，放在bsdiff-4.3解压后的文件夹里。
step5 使用bsdiff生成差异文件PATCH.patch，命令格式：bsdiff oldfile newfile patchfile（这一步操作可以放在服务端来执行）
bogon:bsdiff-4.3 Tony$ ./bsdiff old.apk new.apk PATCH.patch
-step6 使用bspatch合成新的apk，dest.apk。命令格式：bspatch oldfile newfile patchfile
bogon:bsdiff-4.3 Tony$ ./bspatch old.apk dest.apk PATCH.patch
step7 验证生成的dest.apk和之前的new.apk使用一样，验证两个apk的md5值，即可。
bogon:bsdiff-4.3 Tony$ md5 new.apk MD5 (new.apk) = 55005cec2de8ad3668a0fd5bd8746f43 bogon:bsdiff-4.3 Tony$ md5 dest.apk MD5 (dest.apk) = 55005cec2de8ad3668a0fd5bd8746f43 bogon:bsdiff-4.3 Tony$ md5 old.apk MD5 (old.apk) = 822cc0938694008089ea5523f86585d7 bogon:bsdiff-4.3 Tony$
在Android中使用增量更新
ndk部分
step1 新建一个PatchUtils的类，用于调用native的方法
public class PatchUtils { static PatchUtils instance; public static PatchUtils getInstance() { if (instance == null) {
instance = new PatchUtils();
} return instance;
} static {
System.loadLibrary("patchutils");
} /**
* native方法 使用路径为oldApkPath的apk与路径为patchPath的补丁包，合成新的apk，并存储于newApkPath
* <p>
* 返回：0，说明操作成功
*
* @param oldApkPath 示例:/sdcard/old.apk
* @param newApkPath 示例:/sdcard/new.apk
* @param patchPath 示例:/sdcard/xx.patch
* @return
*/
public static native int bspatch(String oldApkPath, String newApkPath, String patchPath);
}step2 使用javah命令生成PatchUtils的头文件，或者使用ndk-build里的javah生成头文件。会在jni文件夹下生成一个com_bigademo_updatedemo_PatchUtils.h的文件，其中com_bigademo_updatedemo是我的包名。
step3 将bsdiff4.3文件夹中的bspatch.c文件导入到jni文件夹下。
step4 将bzip2文件夹导入到jni文件夹下
step5 删除bzip2中的除了以c和h结尾的其他文件。
如图：
jni文件夹目录
step6 修改bspatch.c。引入bzip的文件，引入com_bigademo_updatedemo_PatchUtils.h，在bspatch.c中重写JNIEXPORT jint JNICALL Java_com_bigademo_updatedemo_PatchUtils_bspatch方法。代码如下
#if 0__FBSDID("$FreeBSD: src/usr.bin/bsdiff/bspatch/bspatch.c,v 1.1 2005/08/06 01:59:06 cperciva Exp $");#endif#include <stdlib.h>#include <stdio.h>#include <string.h>#include <err.h>#include <unistd.h>#include <fcntl.h>#include "bzip2/bzlib.c"#include "bzip2/crctable.c"#include "bzip2/compress.c"#include "bzip2/decompress.c"#include "bzip2/randtable.c"#include "bzip2/blocksort.c"#include "bzip2/huffman.c"#include <com_bigademo_updatedemo_PatchUtils.h>JNIEXPORT jint JNICALL Java_com_bigademo_updatedemo_PatchUtils_bspatch(JNIEnv *env,
jclass cls, jstring old, jstring new, jstring patch) { int argc = 4; char * argv[argc];
argv[0] = "bsdiff";
argv[1] = (char*) ((*env)->GetStringUTFChars(env, old, 0));
argv[2] = (char*) ((*env)->GetStringUTFChars(env, new, 0));
argv[3] = (char*) ((*env)->GetStringUTFChars(env, patch, 0)); printf("old apk = %s \n", argv[1]); printf("new apk = %s \n", argv[2]); printf("patch = %s \n", argv[3]); int ret = genpatch(argc, argv); printf("genDiff result = %d ", ret);
(*env)->ReleaseStringUTFChars(env, old, argv[1]);
(*env)->ReleaseStringUTFChars(env, new, argv[2]);
(*env)->ReleaseStringUTFChars(env, patch, argv[3]); return ret;
}static off_t offtin(u_char *buf){ off_t y;
y=buf[7]&0x7F;
y=y*256;y+=buf[6];
y=y*256;y+=buf[5];
y=y*256;y+=buf[4];
y=y*256;y+=buf[3];
y=y*256;y+=buf[2];
y=y*256;y+=buf[1];
y=y*256;y+=buf[0]; if(buf[7]&0x80) y=-y; return y;
}int genpatch(int argc,char * argv[]){
FILE * f, * cpf, * dpf, * epf;
BZFILE * cpfbz2, * dpfbz2, * epfbz2; int cbz2err, dbz2err, ebz2err; int fd; ssize_t oldsize,newsize; ssize_t bzctrllen,bzdatalen;
u_char header[32],buf[8];
u_char *old, *new; off_t oldpos,newpos; off_t ctrl[3]; off_t lenread; off_t i; if(argc!=4) errx(1,"usage: %s oldfile newfile patchfile\n",argv[0]); /* Open patch file */
if ((f = fopen(argv[3], "r")) == NULL)
err(1, "fopen(%s)", argv[3]); /*
File format:
0 8 "BSDIFF40"
8 8 X
16 8 Y
24 8 sizeof(newfile)
32 X bzip2(control block)
32+X Y bzip2(diff block)
32+X+Y ??? bzip2(extra block)
with control block a set of triples (x,y,z) meaning "add x bytes
from oldfile to x bytes from the diff block; copy y bytes from the
extra block; seek forwards in oldfile by z bytes".
*/
/* Read header */
if (fread(header, 1, 32, f) < 32) { if (feof(f))
errx(1, "Corrupt patch\n");
err(1, "fread(%s)", argv[3]);
} /* Check for appropriate magic */
if (memcmp(header, "BSDIFF40", 8) != 0)
errx(1, "Corrupt patch\n"); /* Read lengths from header */
bzctrllen=offtin(header+8);
bzdatalen=offtin(header+16);
newsize=offtin(header+24); if((bzctrllen<0) || (bzdatalen<0) || (newsize<0))
errx(1,"Corrupt patch\n"); /* Close patch file and re-open it via libbzip2 at the right places */
if (fclose(f))
err(1, "fclose(%s)", argv[3]); if ((cpf = fopen(argv[3], "r")) == NULL)
err(1, "fopen(%s)", argv[3]); if (fseeko(cpf, 32, SEEK_SET))
err(1, "fseeko(%s, %lld)", argv[3],
(long long)32); if ((cpfbz2 = BZ2_bzReadOpen(&cbz2err, cpf, 0, 0, NULL, 0)) == NULL)
errx(1, "BZ2_bzReadOpen, bz2err = %d", cbz2err); if ((dpf = fopen(argv[3], "r")) == NULL)
err(1, "fopen(%s)", argv[3]); if (fseeko(dpf, 32 + bzctrllen, SEEK_SET))
err(1, "fseeko(%s, %lld)", argv[3],
(long long)(32 + bzctrllen)); if ((dpfbz2 = BZ2_bzReadOpen(&dbz2err, dpf, 0, 0, NULL, 0)) == NULL)
errx(1, "BZ2_bzReadOpen, bz2err = %d", dbz2err); if ((epf = fopen(argv[3], "r")) == NULL)
err(1, "fopen(%s)", argv[3]); if (fseeko(epf, 32 + bzctrllen + bzdatalen, SEEK_SET))
err(1, "fseeko(%s, %lld)", argv[3],
(long long)(32 + bzctrllen + bzdatalen)); if ((epfbz2 = BZ2_bzReadOpen(&ebz2err, epf, 0, 0, NULL, 0)) == NULL)
errx(1, "BZ2_bzReadOpen, bz2err = %d", ebz2err); if(((fd=open(argv[1],O_RDONLY,0))<0) ||
((oldsize=lseek(fd,0,SEEK_END))==-1) ||
((old=malloc(oldsize+1))==NULL) ||
(lseek(fd,0,SEEK_SET)!=0) ||
(read(fd,old,oldsize)!=oldsize) ||
(close(fd)==-1)) err(1,"%s",argv[1]); if((new=malloc(newsize+1))==NULL) err(1,NULL);
oldpos=0;newpos=0; while(newpos<newsize) { /* Read control data */
for(i=0;i<=2;i++) {
lenread = BZ2_bzRead(&cbz2err, cpfbz2, buf, 8); if ((lenread < 8) || ((cbz2err != BZ_OK) &&
(cbz2err != BZ_STREAM_END)))
errx(1, "Corrupt patch\n");
ctrl[i]=offtin(buf);
}; /* Sanity-check */
if(newpos+ctrl[0]>newsize)
errx(1,"Corrupt patch\n"); /* Read diff string */
lenread = BZ2_bzRead(&dbz2err, dpfbz2, new + newpos, ctrl[0]); if ((lenread < ctrl[0]) ||
((dbz2err != BZ_OK) && (dbz2err != BZ_STREAM_END)))
errx(1, "Corrupt patch\n"); /* Add old data to diff string */
for(i=0;i<ctrl[0];i++) if((oldpos+i>=0) && (oldpos+i<oldsize)) new[newpos+i]+=old[oldpos+i]; /* Adjust pointers */
newpos+=ctrl[0];
oldpos+=ctrl[0]; /* Sanity-check */
if(newpos+ctrl[1]>newsize)
errx(1,"Corrupt patch\n"); /* Read extra string */
lenread = BZ2_bzRead(&ebz2err, epfbz2, new + newpos, ctrl[1]); if ((lenread < ctrl[1]) ||
((ebz2err != BZ_OK) && (ebz2err != BZ_STREAM_END)))
errx(1, "Corrupt patch\n"); /* Adjust pointers */
newpos+=ctrl[1];
oldpos+=ctrl[2];
}; /* Clean up the bzip2 reads */
BZ2_bzReadClose(&cbz2err, cpfbz2);
BZ2_bzReadClose(&dbz2err, dpfbz2);
BZ2_bzReadClose(&ebz2err, epfbz2); if (fclose(cpf) || fclose(dpf) || fclose(epf))
err(1, "fclose(%s)", argv[3]); /* Write the new file */
if(((fd=open(argv[2],O_CREAT|O_TRUNC|O_WRONLY,0666))<0) ||
(write(fd,new,newsize)!=newsize) || (close(fd)==-1))
err(1,"%s",argv[2]); free(new); free(old); return 0;
}step7 在jni下创建Android.mk和Application.mk两个文件
Android.mk
# 构建系统提供的宏函数 my-dir 将返回当前目录（包含 Android.mk 文件本身的目录）的路径，基本上是固定的，不需要去动LOCAL_PATH := $(call my-dir)# 会清除很多 LOCAL_XXX 变量，不会清除 LOCAL_PATH，基本上是固定的，不需要去动include $(CLEAR_VARS)# 需要构建模块的名称，会自动生成相应的 libNDKSample.so 文件，每个模块名称必须唯一，且不含任何空格LOCAL_MODULE := patchutils# 包含要构建到模块中的 C 或 C++ 源文件列表LOCAL_SRC_FILES := bspatch.c LOCAL_C_INCLUDES := /Users/Tony/Code/android/AndroidStudioProjects/demo/updatedemo/app/src/main/jni/bzip2# 帮助系统将所有内容连接到一起，固定的，不需要去动include $(BUILD_SHARED_LIBRARY)
Application.mk
APP_PLATFORM := android-16# 选择不同的 ABI，多个使用空格作为分隔符，全部是allAPP_ABI := all
step8 在module中的build.gradle中配置ndk。
android{
...
defaultConfig{
ndk{ //这个名字就是在PatchUtils中loadLibrary的名字，同时和Android.mk中的LOCAL_MODULE的名字一样，也和生成的so的文件的名字类似。
moduleName "patchutils"
}
}
externalNativeBuild {
ndkBuild {
path "src/main/jni/Android.mk"
}
}
}java部分
创建一个ApkExtract类，用于获取当前app的apk和安装新的apk。因为涉及到Android 7.0的，需要处理Provider的问题，同时在AndroidManifest.xml增加一些代码
public class ApkExtract { public static String extract(Context context) {
context = context.getApplicationContext();
ApplicationInfo applicationInfo = context.getApplicationInfo();
String apkPath = applicationInfo.sourceDir;
Log.d("info", apkPath); return apkPath;
} public static void install(Context context, String apkPath) {
Intent intent = new Intent(Intent.ACTION_VIEW); if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.N) {
intent.setFlags(Intent.FLAG_GRANT_READ_URI_PERMISSION);
Uri contentUri = FileProvider.getUriForFile(context, BuildConfig.APPLICATION_ID + ".fileProvider", new File(apkPath));
intent.setDataAndType(contentUri, "application/vnd.android.package-archive");
} else {
intent.setFlags(Intent.FLAG_ACTIVITY_NEW_TASK);
intent.setDataAndType(Uri.fromFile(new File(apkPath)), "application/vnd.android.package-archive");
}
context.startActivity(intent);
}
}androidmanifest.xml
<application
android:allowBackup="true"
android:icon="@mipmap/ic_launcher"
android:label="@string/app_name"
android:roundIcon="@mipmap/ic_launcher_round"
android:supportsRtl="true"
android:theme="@style/AppTheme">
<provider
android:name="android.support.v4.content.FileProvider"
android:authorities="${applicationId}.fileProvider"
android:grantUriPermissions="true"
android:exported="false">
<meta-data
android:name="android.support.FILE_PROVIDER_PATHS"
android:resource="@xml/file_paths" />
... </application>最后在需要更新的时候调用下面这个方法，当然先做一下动态调用读写权限的操作。
if (ContextCompat.checkSelfPermission(MainActivity.this, android.Manifest.permission.WRITE_EXTERNAL_STORAGE) != PackageManager.PERMISSION_GRANTED) {
ActivityCompat.requestPermissions(MainActivity.this, new String[]{android.Manifest.permission.WRITE_EXTERNAL_STORAGE}, 2);
} else {
doBspatch();// startActivity(new Intent(MainActivity.this, SecondActivity.class));
} private void doBspatch() { final File destApk = new File(Environment.getExternalStorageDirectory(), "dest.apk"); final File patch = new File(Environment.getExternalStorageDirectory(), "PATCH.patch"); //一定要检查文件都存在
int result= PatchUtils.bspatch(ApkExtract.extract(this),
destApk.getAbsolutePath(),
patch.getAbsolutePath());
Log.e("info","patch result "+result); if (destApk.exists()) {
ApkExtract.install(this, destApk.getAbsolutePath());
}
}
作者：Coding小学生
链接：https://www.jianshu.com/p/472d0453656a
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