原创内容，转载请注明出处，多谢配合。
APK经过复制、创建对应包文件夹、安装之后，还剩一个比较重要的点需要分析，那就是dex编译。
上篇在installPackageLI中：
private void installPackageLI(InstallArgs args, PackageInstalledInfo res) {
...
mPackageDexOptimizer.performDexOpt(pkg, pkg.usesLibraryFiles,
null /* instructionSets */, false /* checkProfiles */,
getCompilerFilterForReason(REASON_INSTALL),
getOrCreateCompilerPackageStats(pkg),
mDexManager.isUsedByOtherApps(pkg.packageName));
...
}
执行dex编译优化
frameworks/base/services/core/java/com/android/server/pm/PackageDexOptimizer.java
int performDexOpt(PackageParser.Package pkg, String[] sharedLibraries,
String[] instructionSets, boolean checkProfiles, String targetCompilationFilter,
CompilerStats.PackageStats packageStats, boolean isUsedByOtherApps) {
...
return performDexOptLI(pkg, sharedLibraries, instructionSets, checkProfiles,
...
}
继续看performDexOptLI
/**
* Performs dexopt on all code paths and libraries of the specified package for specified
* instruction sets.
*
* Calls to {@link com.android.server.pm.Installer#dexopt} on {@link #mInstaller} are
* synchronized on {@link #mInstallLock}.
*/
private int performDexOptLI(PackageParser.Package pkg, String[] sharedLibraries,
String[] targetInstructionSets, boolean checkForProfileUpdates,
String targetCompilerFilter, CompilerStats.PackageStats packageStats,
boolean isUsedByOtherApps) {
...
for (String dexCodeIsa : dexCodeInstructionSets) {
int newResult = dexOptPath(pkg, path, dexCodeIsa, compilerFilter, profileUpdated,
sharedLibrariesPathWithSplits, dexoptFlags, sharedGid, packageStats);
// The end result is:
// - FAILED if any path failed,
// - PERFORMED if at least one path needed compilation,
// - SKIPPED when all paths are up to date
if ((result != DEX_OPT_FAILED) && (newResult != DEX_OPT_SKIPPED)) {
result = newResult;
}
}
}
return result;
}
循环执行dexOptPath
/**
* Performs dexopt on the {@code path} belonging to the package {@code pkg}.
*
* @return
* DEX_OPT_FAILED if there was any exception during dexopt
* DEX_OPT_PERFORMED if dexopt was performed successfully on the given path.
* DEX_OPT_SKIPPED if the path does not need to be deopt-ed.
*/
@GuardedBy("mInstallLock")
private int dexOptPath(PackageParser.Package pkg, String path, String isa,
String compilerFilter, boolean profileUpdated, String sharedLibrariesPath,
int dexoptFlags, int uid, CompilerStats.PackageStats packageStats) {
...
mInstaller.dexopt(path, uid, pkg.packageName, isa, dexoptNeeded, oatDir, dexoptFlags,
compilerFilter, pkg.volumeUuid, sharedLibrariesPath, pkg.applicationInfo.seInfo);
...
}
frameworks/base/services/core/java/com/android/server/pm/Installer.java
private volatile IInstalld mInstalld;
...
IBinder binder = ServiceManager.getService("installd”);
...
mInstalld = IInstalld.Stub.asInterface(binder);
…
public void dexopt(String apkPath, int uid, @Nullable String pkgName, String instructionSet,
int dexoptNeeded, @Nullable String outputPath, int dexFlags,
String compilerFilter, @Nullable String volumeUuid, @Nullable String sharedLibraries,
@Nullable String seInfo)
throws InstallerException {
assertValidInstructionSet(instructionSet);
if (!checkBeforeRemote()) return;
try {
mInstalld.dexopt(apkPath, uid, pkgName, instructionSet, dexoptNeeded, outputPath,
dexFlags, compilerFilter, volumeUuid, sharedLibraries, seInfo);
} catch (Exception e) {
throw InstallerException.from(e);
}
}
这里installd是init启动的native进程，7.0及之前它与Installer是进行socket通信，8.0之后换成了binder，如上代码也明显能看出。
frameworks/native/cmds/installd/installd.cpp
8.0之后也不像7.0的时候在installd.cpp中通过cmds命令对应depot了 { "dexopt", , do_dexopt }，现在操作是在dexopt.cpp中进行。
frameworks/native/cmds/installd/dexopt.cpp
int dexopt(const char* dex_path, uid_t uid, const char* pkgname, const char* instruction_set,
int dexopt_needed, const char* oat_dir, int dexopt_flags, const char* compiler_filter,
const char* volume_uuid, const char* shared_libraries, const char* se_info) {
...
run_dex2oat(input_fd.get(),
out_oat_fd.get(),
in_vdex_fd.get(),
out_vdex_fd.get(),
image_fd.get(),
dex_path,
out_oat_path,
swap_fd.get(),
instruction_set,
compiler_filter,
debuggable,
boot_complete,
reference_profile_fd.get(),
shared_libraries);
...
return 0;
}
最终调用dex2oat进行编译操作。
好了，3篇文章对PMS的安装过程扫了个盲，非常多的细节没有分析，只简单捋了个框架。想深入学习的可以看看这个系列，总结的还挺全面的：APK安装流程详解
最后站在巨人的肩膀上盗两张图来总结下：
参考：
https://blog.csdn.net/shuttlecheng/article/details/79018014