android 包管理系统分析

包管理脚本 /system/bin/pm 解析：
pm的使用方法可以参考
Pm.java (frameworks/base/cmds/pm/src/com/android/commands/pm)文件中的
static void showUsage()函数：
private static void showUsage() {
System.err.println("usage: pm [list|path|install|uninstall]");
System.err.println(" pm list packages [-f]");
System.err.println(" pm list permission-groups");
System.err.println(" pm list permissions [-g] [-f] [-d] [-u] [GROUP]");
System.err.println(" pm list instrumentation [-f] [TARGET-PACKAGE]");
System.err.println(" pm path PACKAGE");
System.err.println(" pm install [-l] [-r] PATH");
System.err.println(" pm uninstall [-k] PACKAGE");
System.err.println(" pm enable PACKAGE_OR_COMPONENT");
System.err.println(" pm disable PACKAGE_OR_COMPONENT");
...
}
脚本 /system/bin/pm 内容：
----------------------------------------------------------
base=/system
export CLASSPATH=$base/framework/pm.jar
exec app_process $base/bin com.android.commands.pm.Pm "$@"
----------------------------------------------------------

pm脚步执行过程分析：
由命令行参数可以知道调用过程如下：
首先进入 App_main.cpp (frameworks/base/cmds/app_process)文件中
AppRuntime 类的 main 函数。
main()
set_process_name(argv0);
runtime.mClassName = arg;
runtime.mArgC = argc-i;
runtime.mArgV = argv+i;
runtime.start();
runtime.start 调用的是 AndroidRuntime.cpp (frameworks/base/core/jni)文件中的：
void AndroidRuntime::start()
start("com.android.internal.os.RuntimeInit",false /* Don't start the system server */);
然后进入 RuntimeInit 类的main函数
RuntimeInit.java (frameworks/base/core/java/com/android/internal/os)
main()
commonInit();
finishInit();
finishInit 实际上本地调用：AndroidRuntime.cpp (frameworks/base/core/jni)中的：
static void com_android_internal_os_RuntimeInit_finishInit(JNIEnv* env, jobject clazz)
gCurRuntime->onStarted();
因为有：
App_main.cpp (frameworks/base/cmds/app_process): virtual void onStarted()
Main_runtime.cpp (frameworks/base/cmds/runtime): virtual void onStarted()
而 class AppRuntime : public AndroidRuntime 并且是由 AppRuntime 类进入 RuntimeInit
所以可以确定 gCurRuntime->onStarted() 调用的是App_main.cpp (frameworks/base/cmds/app_process)中的：
virtual void onStarted() 函数。
app_init(mClassName, mArgC, mArgV);
接着，
status_t app_init(const char* className, int argc, const char* const argv[])
jr->callMain(className, argc, argv);
jr->callMain 调用了 Pm.java (frameworks/base/cmds/pm/src/com/android/commands/pm) 文件中
类 Pm 的main函数
static void main(String[] args)
new Pm().run(args)
在run函数中对参数进行解析。
此处的args 实际上为执行pm脚本时传入的参数。
pm 脚本常见的格式有：
---------------------------------------------------
pm list packages [-f]
显示系统中所有已安装的软件包，-f选项列出他们的相关信息
pm list permission-groups");
pm list permissions [-g] [-f] [-d] [-u] [GROUP]
pm list instrumentation [-f] [TARGET-PACKAGE]
pm path PACKAGE
pm install [-l] [-r] PATH
安装软件包 PATH 为apk文件的路径， -l 表示采用 FORWARD_LOCK 的方式安装，-r 如果一个包存在那么
重新安装，但是保留原来的数据。
pm uninstall [-k] PACKAGE
卸载一个软件包，PACKAGE 为软件包的名称，-k选项表明卸载的时候保留数据和相应的cache目录。
pm enable PACKAGE_OR_COMPONENT
pm disable PACKAGE_OR_COMPONENT
enable 和 disable 修改一个包或者组件(class)的使能状态.
----------------------------------------------------
例如：
我们输入命令 pm install /patch/to/mygps.apk
那么执行的是：runInstall();
void runInstall()
while ((opt=nextOption()) != null) {
if (opt.equals("-l"))
{
installFlags |= PackageManager.FORWARD_LOCK_PACKAGE;
}
else if (opt.equals("-r"))
{
installFlags |= PackageManager.REPLACE_EXISTING_PACKAGE;
}
String apkFilePath = nextArg();
//创建Observer用于包安装过程的监测。
PackageInstallObserver obs = new PackageInstallObserver();
mPm.installPackage(Uri.fromFile(new File(apkFilePath)), obs, installFlags);
如果安装成功：
obs.result == PackageManager.INSTALL_SUCCEEDED
因为有：
IPackageManager mPm;
mPm = IPackageManager.Stub.asInterface(ServiceManager.getService("package"));
class PackageManagerService extends IPackageManager.Stub
所以 mPm.installPackage 调用的是：
PackageManagerService.java (frameworks/base/services/java/com/android/server)文件中的
/* Called when a downloaded package installation has been confirmed by the user */
void installPackage(final Uri packageURI, final IPackageInstallObserver observer, final int flags)
res = installPackageLI(packageURI, flags);
...
Bundle extras = new Bundle(1);
extras.putInt(Intent.EXTRA_UID, res.uid);
...
sendPackageBroadcast(Intent.ACTION_PACKAGE_ADDED,res.pkg.applicationInfo.packageName,extras);
如果包安装成功了，那么将广播一个 ACTION_PACKAGE_ADDED 的消息。
下面的服务和应用程序会监测 ACTION_PACKAGE_ADDED 消息。
AppWidgetService.java (frameworks/base/services/java/com/android/server): filter.addAction(Intent.ACTION_PACKAGE_ADDED);
Home.java (development/samples/home/src/com/example/android/home): filter = new IntentFilter(Intent.ACTION_PACKAGE_ADDED);
InputMethodManagerService.java (frameworks/base/services/java/com/android/server): packageFilt.addAction(Intent.ACTION_PACKAGE_ADDED);
Launcher.java (packages/apps/launcher/src/com/android/launcher): IntentFilter filter = new IntentFilter(Intent.ACTION_PACKAGE_ADDED);
ManageApplications.java (packages/apps/settings/src/com/android/settings): IntentFilter filter = new IntentFilter(Intent.ACTION_PACKAGE_ADDED);
PackageBrowser.java (development/apps/development/src/com/android/development):IntentFilter filter = new IntentFilter(Intent.ACTION_PACKAGE_ADDED);
SearchDialog.java (frameworks/base/core/java/android/app): mPackageFilter.addAction(Intent.ACTION_PACKAGE_ADDED);
SearchManagerService.java (frameworks/base/core/java/android/server/search): filter.addAction(Intent.ACTION_PACKAGE_ADDED);

下面将分析 SearchManagerService 服务对 ACTION_PACKAGE_ADDED 消息的监测过程：
由pm的脚本分析，我们可以知道，安装一个包后会广播 ACTION_PACKAGE_ADDED 消息。
而在 SearchManagerService 的构造函数SearchManagerService(Context context)中
通过：
// Setup the infrastructure for updating and maintaining the list
// of searchable activities.
IntentFilter filter = new IntentFilter();
filter.addAction(Intent.ACTION_PACKAGE_ADDED);
filter.addAction(Intent.ACTION_PACKAGE_REMOVED);
filter.addAction(Intent.ACTION_PACKAGE_CHANGED);
filter.addDataScheme("package");
mContext.registerReceiver(mIntentReceiver, filter, null, mHandler);
添加了对 ACTION_PACKAGE_ADDED 消息的监测。
当收到 ACTION_PACKAGE_ADDED 消息后，会执行
void onReceive(Context context, Intent intent)
mHandler.post(mRunUpdateSearchable);
接着，
private Runnable mRunUpdateSearchable = new Runnable()
执行 run
run 调用 updateSearchables();
SearchManagerService.java (frameworks/base/core/java/android/server/search)
private void updateSearchables()
SearchableInfo.buildSearchableList(mContext);
ComponentName defaultSearch = new ComponentName(
"com.android.googlesearch",
"com.android.googlesearch.GoogleSearch" );
SearchableInfo.setDefaultSearchable(mContext, defaultSearch);
由：
ComponentName.java (frameworks/base/core/java/android/content)
public ComponentName(String pkg, String cls)
public ComponentName(Context pkg, String cls)
public ComponentName(Context pkg, Class<?> cls)
new ComponentName 调用的是 public ComponentName(String pkg, String cls)

void buildSearchableList(Context context)
//use intent resolver to generate list of ACTION_SEARCH receivers
final PackageManager pm = context.getPackageManager();
List<ResolveInfo> infoList;
final Intent intent = new Intent(Intent.ACTION_SEARCH);
infoList = pm.queryIntentActivities(intent, PackageManager.GET_META_DATA);

static void setDefaultSearchable(Context context,ComponentName activity)
si = getSearchableInfo(context, activity);
if (si != null) {
// move to front of list
sSearchablesList.remove(si);
sSearchablesList.add(0, si);
}
接着，
static SearchableInfo getSearchableInfo(Context context, ComponentName activity)

补充信息：
getLaunchIntentForPackage
getInstalledPackages
getInstalledApplications
getDefaultActivityIcon
getApplicationLabel
addPackageToPreferred

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