Android So动态加载原理分析与优雅实现
/**
* com.google.android.apps.photolab.storyboard.soloader.LoadLibraryUtil
* Description:动态加载so文件的核心，注入so路径到nativeLibraryDirectories数组第一个位置，会优先从这个位置查找so
* 更多姿势，请参考开源库动态更新so的黑科技，仅供学习交流
*
*/
public class LoadLibraryUtil {
private static final String TAG = LoadLibraryUtil.class.getSimpleName() + "-duqian";
private static File lastSoDir = null;
public static synchronized boolean installNativeLibraryPath(ClassLoader classLoader, File folder)
throws Throwable {
if (classLoader == null || folder == null || !folder.exists()) {
Log.e(TAG, "classLoader or folder is illegal " + folder);
return false;
}
final int sdkInt = Build.VERSION.SDK_INT;
final boolean aboveM = (sdkInt == 25 && getPreviousSdkInt() != 0) || sdkInt > 25;
if (aboveM) {
try {
V25.install(classLoader, folder);
} catch (Throwable throwable) {
try {
V23.install(classLoader, folder);
} catch (Throwable throwable1) {
V14.install(classLoader, folder);
}
}
} else if (sdkInt >= 23) {
try {
V23.install(classLoader, folder);
} catch (Throwable throwable) {
V14.install(classLoader, folder);
}
} else if (sdkInt >= 14) {
V14.install(classLoader, folder);
}
lastSoDir = folder;
return true;
}
private static final class V23 {
private static void install(ClassLoader classLoader, File folder) throws Throwable {
Field pathListField = ReflectUtil.findField(classLoader, "pathList");
Object dexPathList = pathListField.get(classLoader);
Field nativeLibraryDirectories = ReflectUtil.findField(dexPathList, "nativeLibraryDirectories");
List<File> libDirs = (List<File>) nativeLibraryDirectories.get(dexPathList);
//去重
if (libDirs == null) {
libDirs = new ArrayList<>(2);
}
final Iterator<File> libDirIt = libDirs.iterator();
while (libDirIt.hasNext()) {
final File libDir = libDirIt.next();
if (folder.equals(libDir) || folder.equals(lastSoDir)) {
libDirIt.remove();
Log.d(TAG, "dq libDirIt.remove() " + folder.getAbsolutePath());
break;
}
}
libDirs.add(0, folder);
Field systemNativeLibraryDirectories =
ReflectUtil.findField(dexPathList, "systemNativeLibraryDirectories");
List<File> systemLibDirs = (List<File>) systemNativeLibraryDirectories.get(dexPathList);
//判空
if (systemLibDirs == null) {
systemLibDirs = new ArrayList<>(2);
}
Log.d(TAG, "dq systemLibDirs,size=" + systemLibDirs.size());
Method makePathElements = ReflectUtil.findMethod(dexPathList, "makePathElements", List.class, File.class, List.class);
ArrayList<IOException> suppressedExceptions = new ArrayList<>();
libDirs.addAll(systemLibDirs);
Object[] elements = (Object[]) makePathElements.invoke(dexPathList, libDirs, null, suppressedExceptions);
Field nativeLibraryPathElements = ReflectUtil.findField(dexPathList, "nativeLibraryPathElements");
nativeLibraryPathElements.setAccessible(true);
nativeLibraryPathElements.set(dexPathList, elements);
}
}
/**
* 把自定义的native库path插入nativeLibraryDirectories最前面，即使安装包libs目录里面有同名的so，也优先加载指定路径的外部so
*/
private static final class V25 {
private static void install(ClassLoader classLoader, File folder) throws Throwable {
Field pathListField = ReflectUtil.findField(classLoader, "pathList");
Object dexPathList = pathListField.get(classLoader);
Field nativeLibraryDirectories = ReflectUtil.findField(dexPathList, "nativeLibraryDirectories");
List<File> libDirs = (List<File>) nativeLibraryDirectories.get(dexPathList);
//去重
if (libDirs == null) {
libDirs = new ArrayList<>(2);
}
final Iterator<File> libDirIt = libDirs.iterator();
while (libDirIt.hasNext()) {
final File libDir = libDirIt.next();
if (folder.equals(libDir) || folder.equals(lastSoDir)) {
libDirIt.remove();
Log.d(TAG, "dq libDirIt.remove()" + folder.getAbsolutePath());
break;
}
}
libDirs.add(0, folder);
//system/lib
Field systemNativeLibraryDirectories = ReflectUtil.findField(dexPathList, "systemNativeLibraryDirectories");
List<File> systemLibDirs = (List<File>) systemNativeLibraryDirectories.get(dexPathList);
//判空
if (systemLibDirs == null) {
systemLibDirs = new ArrayList<>(2);
}
Log.d(TAG, "dq systemLibDirs,size=" + systemLibDirs.size());
Method makePathElements = ReflectUtil.findMethod(dexPathList, "makePathElements", List.class);
libDirs.addAll(systemLibDirs);
Object[] elements = (Object[]) makePathElements.invoke(dexPathList, libDirs);
Field nativeLibraryPathElements = ReflectUtil.findField(dexPathList, "nativeLibraryPathElements");
nativeLibraryPathElements.setAccessible(true);
nativeLibraryPathElements.set(dexPathList, elements);
}
}
private static final class V14 {
private static void install(ClassLoader classLoader, File folder) throws Throwable {
Field pathListField = ReflectUtil.findField(classLoader, "pathList");
Object dexPathList = pathListField.get(classLoader);
ReflectUtil.expandFieldArray(dexPathList, "nativeLibraryDirectories", new File[]{folder});
}
}
/**
* fuck部分机型删了该成员属性，兼容
*
* @return 被厂家删了返回1，否则正常读取
*/
@TargetApi(Build.VERSION_CODES.M)
private static int getPreviousSdkInt() {
try {
return Build.VERSION.PREVIEW_SDK_INT;
} catch (Throwable ignore) {
}
return 1;
}
}
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