androiod 學習--PMS應用安裝過程
阿新 • • 發佈：2018-12-31
前面,我們已經分析了，PMS我們已經分析了，PackageManagerService整個的啟動過程，對android應用管理大概有一個大概的瞭解，實際開發中可以有一個更深入的理解，前面講的只是一個管理大概的流程，以及資料如何儲存，儲存大部分都是用hashmap來儲存的，這樣儲存也是為了查詢方便，不過唯一不好的就是浪費空間。所以android的速度提升了，不過rom執行大小也增大了。
費話少說了，我們還是繼續分析應用的安裝過程。一般應用安裝，我們都是獲取PackageManager 然後呼叫installPackage方法，不過PackageManager真正的實現類是ApplicationPackageManager,我們看一下具體的實現：
這裡也只是呼叫PMS去實現安裝，所以要分析安裝的過程，我們也還是要分析PMS裡面的installPackage方法。不過經過各種跳轉，最終還是會走到installPackageWithVerificationAndEncryption方法裡面去，主要是生成一個InstallParams物件傳送一個copy的訊息。public void installPackage(Uri packageURI, IPackageInstallObserver observer, int flags, String installerPackageName) { try { mPM.installPackage(packageURI, observer, flags, installerPackageName); } catch (RemoteException e) { // Should never happen! } }
InstallParams是繼承HandlerParams物件，主要是實現apk復現等其他功能。看Handler關於INIT_COPY的處理：final Message msg = mHandler.obtainMessage(INIT_COPY); msg.obj = new InstallParams(packageURI, observer, filteredFlags, installerPackageName, verificationParams, encryptionParams, user); mHandler.sendMessage(msg);
HandlerParams params = (HandlerParams) msg.obj;
int idx = mPendingInstalls.size();
if (DEBUG_INSTALL) Slog.i(TAG, "init_copy idx=" + idx + ": " + params);
// If a bind was already initiated we dont really
// need to do anything. The pending install
// will be processed later on.
if (!mBound) {
// If this is the only one pending we might
// have to bind to the service again.
if (!connectToService()) {
Slog.e(TAG, "Failed to bind to media container service");
params.serviceError();
return;
} else {
// Once we bind to the service, the first
// pending request will be processed.
mPendingInstalls.add(idx, params);
}
} else {
mPendingInstalls.add(idx, params);
// Already bound to the service. Just make
// sure we trigger off processing the first request.
if (idx == 0) {
mHandler.sendEmptyMessage(MCS_BOUND);
}
}
break;
}2.沒有繫結service，則要進行繫結再新增到mPendingInstalls 佇列裡面。
再看一下：
HandlerParams params = mPendingInstalls.get(0);
if (params != null) {
if (params.startCopy()) {
// We are done... look for more work or to
// go idle.
if (DEBUG_SD_INSTALL) Log.i(TAG,
"Checking for more work or unbind...");
// Delete pending install
if (mPendingInstalls.size() > 0) {
mPendingInstalls.remove(0);
}
if (mPendingInstalls.size() == 0) {
if (mBound) {
if (DEBUG_SD_INSTALL) Log.i(TAG,
"Posting delayed MCS_UNBIND");
removeMessages(MCS_UNBIND);
Message ubmsg = obtainMessage(MCS_UNBIND);
// Unbind after a little delay, to avoid
// continual thrashing.
sendMessageDelayed(ubmsg, 10000);
}
} else {
// There are more pending requests in queue.
// Just post MCS_BOUND message to trigger processing
// of next pending install.
if (DEBUG_SD_INSTALL) Log.i(TAG,
"Posting MCS_BOUND for next woek");
mHandler.sendEmptyMessage(MCS_BOUND);
} if (mTempPackage != null) {
ParcelFileDescriptor out;
try {
out = ParcelFileDescriptor.open(mTempPackage,
ParcelFileDescriptor.MODE_READ_WRITE);
} catch (FileNotFoundException e) {
out = null;
Slog.e(TAG, "Failed to create temporary file for : " + mPackageURI);
}
// Make a temporary file for decryption.
ret = mContainerService
.copyResource(mPackageURI, encryptionParams, out);
IoUtils.closeQuietly(out);
packageFile = mTempPackage;
FileUtils.setPermissions(packageFile.getAbsolutePath(),
FileUtils.S_IRUSR | FileUtils.S_IWUSR | FileUtils.S_IRGRP
| FileUtils.S_IROTH,
-1, -1);
} else {
packageFile = null;
}
} else {
packageFile = new File(mPackageURI.getPath());
}
if (packageFile != null) {
// Remote call to find out default install location
final String packageFilePath = packageFile.getAbsolutePath();
pkgLite = mContainerService.getMinimalPackageInfo(packageFilePath, flags,
lowThreshold);
/*
* If we have too little free space, try to free cache
* before giving up.
*/
if (pkgLite.recommendedInstallLocation
== PackageHelper.RECOMMEND_FAILED_INSUFFICIENT_STORAGE) {
final long size = mContainerService.calculateInstalledSize(
packageFilePath, isForwardLocked());
if (mInstaller.freeCache(size + lowThreshold) >= 0) {
pkgLite = mContainerService.getMinimalPackageInfo(packageFilePath,
flags, lowThreshold);
}
/*
* The cache free must have deleted the file we
* downloaded to install.
*
* TODO: fix the "freeCache" call to not delete
* the file we care about.
*/
if (pkgLite.recommendedInstallLocation
== PackageHelper.RECOMMEND_FAILED_INVALID_URI) {
pkgLite.recommendedInstallLocation
= PackageHelper.RECOMMEND_FAILED_INSUFFICIENT_STORAGE;
}
}
}
} finally {
mContext.revokeUriPermission(mPackageURI,
Intent.FLAG_GRANT_READ_URI_PERMISSION);
}
} public PackageInfoLite getMinimalPackageInfo(final String packagePath, int flags,
long threshold) {
PackageInfoLite ret = new PackageInfoLite();
if (packagePath == null) {
Slog.i(TAG, "Invalid package file " + packagePath);
ret.recommendedInstallLocation = PackageHelper.RECOMMEND_FAILED_INVALID_APK;
return ret;
}
DisplayMetrics metrics = new DisplayMetrics();
metrics.setToDefaults();
PackageParser.PackageLite pkg = PackageParser.parsePackageLite(packagePath, 0);
if (pkg == null) {
Slog.w(TAG, "Failed to parse package");
final File apkFile = new File(packagePath);
if (!apkFile.exists()) {
ret.recommendedInstallLocation = PackageHelper.RECOMMEND_FAILED_INVALID_URI;
} else {
ret.recommendedInstallLocation = PackageHelper.RECOMMEND_FAILED_INVALID_APK;
}
return ret;
}
ret.packageName = pkg.packageName;
ret.versionCode = pkg.versionCode;
ret.installLocation = pkg.installLocation;
ret.verifiers = pkg.verifiers;
ret.recommendedInstallLocation = recommendAppInstallLocation(pkg.installLocation,
packagePath, flags, threshold);
return ret;
}recommendAppInstallLocation 讀取設定裡面的資訊和apk 本身設定的安裝路徑，根據剩下空間等因素，確定最終路徑.
接下來建立InstallArgs ,createInstallArgs方法會根據不同的安裝路徑選擇生成物件.再呼叫copyApk方法複製 apk包，lib庫等。
最後，再看一下handleReturnCode方法：主要是做掃尾工作，刪除臨時檔案，不過最重要的還是processPendingInstall方法：
第一.掃描apk，解析然後把資料充分(把應用的相關資訊新增到 Settings裡面);
第二.傳送POST_INSTALL刪除安裝過程中生成的臨時檔案。