應(yīng)用安裝策略之可用存儲空間閾值
對于從來沒有深入看過源碼的我來說，峰哥真的給我安排了一個棘手且完全不熟悉的任務(wù)聘惦。但是我也只好硬著頭皮往下做遮婶，期間參考了網(wǎng)上的一些文章，啟碩哥也指點了我不少猛蔽，最終還是找到了規(guī)定的閾值剥悟。
期間代碼不需要全看灵寺，只看畫出來的重點部分即可。貼出源碼是為了方便查漏補(bǔ)缺区岗。
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參考打包安裝程序
- 發(fā)現(xiàn)基本都是調(diào)用android.content.pm.PackageManager
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網(wǎng)上查詢各種安裝方式
通過shell命令的
pm install <packgename>通過調(diào)用android.content.pm.PackageManager
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以上兩種方式發(fā)現(xiàn)無論怎么樣最終都會調(diào)用 installer.java
installer.java 最終回到PackageManagerService
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在滿負(fù)荷調(diào)試中出現(xiàn)
INSTALL_FAILED_INSUFFICIENT_STORAGE- 通過AndroidXRef 查詢結(jié)果定位到PackageManagerService.java
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根據(jù)上述兩步跟蹤問題略板，找到 PackageManagerService.java
frameworks\base\services\java\com\android\server\pm\PackageManagerService.java
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找到 InstallParams 類
- 這一整段基本就是安裝所需的各個流程，但是我們只看其中和存儲空間相關(guān)的策略
class InstallParams extends HandlerParams {
//......
private InstallArgs mArgs;
private int mRet;
private File mTempPackage;
//.......
private int installLocationPolicy(PackageInfoLite pkgLite, int flags) {
String packageName = pkgLite.packageName;
int installLocation = pkgLite.installLocation;
boolean onSd = (flags & PackageManager.INSTALL_EXTERNAL) != 0;
// reader
synchronized (mPackages) {
PackageParser.Package pkg = mPackages.get(packageName);
if (pkg != null) {
if ((flags & PackageManager.INSTALL_REPLACE_EXISTING) != 0) {
// Check for downgrading.
if ((flags & PackageManager.INSTALL_ALLOW_DOWNGRADE) == 0) {
if (pkgLite.versionCode < pkg.mVersionCode) {
Slog.w(TAG, "Can't install update of " + packageName
+ " update version " + pkgLite.versionCode
+ " is older than installed version "
+ pkg.mVersionCode);
return PackageHelper.RECOMMEND_FAILED_VERSION_DOWNGRADE;
}
}
// Check for updated system application.
if ((pkg.applicationInfo.flags & ApplicationInfo.FLAG_SYSTEM) != 0) {
if (onSd) {
Slog.w(TAG, "Cannot install update to system app on sdcard");
return PackageHelper.RECOMMEND_FAILED_INVALID_LOCATION;
}
return PackageHelper.RECOMMEND_INSTALL_INTERNAL;
} else {
if (onSd) {
// Install flag overrides everything.
return PackageHelper.RECOMMEND_INSTALL_EXTERNAL;
}
// If current upgrade specifies particular preference
if (installLocation == PackageInfo.INSTALL_LOCATION_INTERNAL_ONLY) {
// Application explicitly specified internal.
return PackageHelper.RECOMMEND_INSTALL_INTERNAL;
} else if (installLocation == PackageInfo.INSTALL_LOCATION_PREFER_EXTERNAL) {
// App explictly prefers external. Let policy decide
} else {
// Prefer previous location
if (isExternal(pkg)) {
return PackageHelper.RECOMMEND_INSTALL_EXTERNAL;
}
return PackageHelper.RECOMMEND_INSTALL_INTERNAL;
}
}
} else {
// Invalid install. Return error code
return PackageHelper.RECOMMEND_FAILED_ALREADY_EXISTS;
}
}
}
// All the special cases have been taken care of.
// Return result based on recommended install location.
if (onSd) {
return PackageHelper.RECOMMEND_INSTALL_EXTERNAL;
}
return pkgLite.recommendedInstallLocation;
}
/*
* Invoke remote method to get package information and install
* location values. Override install location based on default
* policy if needed and then create install arguments based
* on the install location.
*/
public void handleStartCopy() throws RemoteException {
int ret = PackageManager.INSTALL_SUCCEEDED;
final boolean onSd = (flags & PackageManager.INSTALL_EXTERNAL) != 0;
final boolean onInt = (flags & PackageManager.INSTALL_INTERNAL) != 0;
PackageInfoLite pkgLite = null;
if (onInt && onSd) {
// Check if both bits are set.
Slog.w(TAG, "Conflicting flags specified for installing on both internal and external");
ret = PackageManager.INSTALL_FAILED_INVALID_INSTALL_LOCATION;
} else {
final long lowThreshold;
final DeviceStorageMonitorService dsm = (DeviceStorageMonitorService) ServiceManager
.getService(DeviceStorageMonitorService.SERVICE);
if (dsm == null) {
Log.w(TAG, "Couldn't get low memory threshold; no free limit imposed");
lowThreshold = 0L;
} else {
lowThreshold = dsm.getMemoryLowThreshold();
}
try {
//......
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);
}
}
if (ret == PackageManager.INSTALL_SUCCEEDED) {
int loc = pkgLite.recommendedInstallLocation;
if (loc == PackageHelper.RECOMMEND_FAILED_INVALID_LOCATION) {
//......
} else if (loc == PackageHelper.RECOMMEND_FAILED_INSUFFICIENT_STORAGE) {
ret = PackageManager.INSTALL_FAILED_INSUFFICIENT_STORAGE;
} else if (loc == PackageHelper.RECOMMEND_FAILED_INVALID_APK) {
//......
}
}
final InstallArgs args = createInstallArgs(this);
mArgs = args;
//......
}
//......
}
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找到重點 handleStartCopy 函數(shù)
- 出現(xiàn)了前面提到的
INSTALL_FAILED_INSUFFICIENT_STORAGE
- 出現(xiàn)了前面提到的
public void handleStartCopy() throws RemoteException {
int ret = PackageManager.INSTALL_SUCCEEDED;
final boolean onSd = (flags & PackageManager.INSTALL_EXTERNAL) != 0;
final boolean onInt = (flags & PackageManager.INSTALL_INTERNAL) != 0;
PackageInfoLite pkgLite = null;
if (onInt && onSd) {
// Check if both bits are set.
Slog.w(TAG, "Conflicting flags specified for installing on both internal and external");
ret = PackageManager.INSTALL_FAILED_INVALID_INSTALL_LOCATION;
} else {
final long lowThreshold;
final DeviceStorageMonitorService dsm = (DeviceStorageMonitorService) ServiceManager
.getService(DeviceStorageMonitorService.SERVICE);
if (dsm == null) {
Log.w(TAG, "Couldn't get low memory threshold; no free limit imposed");
lowThreshold = 0L;
} else {
lowThreshold = dsm.getMemoryLowThreshold();
}
try {
//......
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);
}
}
if (ret == PackageManager.INSTALL_SUCCEEDED) {
int loc = pkgLite.recommendedInstallLocation;
if (loc == PackageHelper.RECOMMEND_FAILED_INVALID_LOCATION) {
//......
} else if (loc == PackageHelper.RECOMMEND_FAILED_INSUFFICIENT_STORAGE) {
ret = PackageManager.INSTALL_FAILED_INSUFFICIENT_STORAGE;
} else if (loc == PackageHelper.RECOMMEND_FAILED_INVALID_APK) {
//......
}
}
final InstallArgs args = createInstallArgs(this);
mArgs = args;
//......
}
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其中有獲取最低存儲空間的信息 lowThreshold
- dsm是 DeviceStorageMonitorService 的實體
final long lowThreshold;
final DeviceStorageMonitorService dsm = (DeviceStorageMonitorService) ServiceManager.getService(DeviceStorageMonitorService.SERVICE);
if (dsm == null) {
Log.w(TAG, "Couldn't get low memory threshold; no free limit imposed");
lowThreshold = 0L;
} else {
lowThreshold = dsm.getMemoryLowThreshold();
}
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找到 DeviceStorageMonitorService 類
frameworks\base\services\java\com\android\server\DeviceStorageMonitorService.java
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找到 getMemoryLowThreshold
public long getMemoryLowThreshold() {
return mMemLowThreshold;
}
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找到 mMemLowThreshold
final StorageManager sm = StorageManager.from(context);
mMemLowThreshold = sm.getStorageLowBytes(DATA_PATH);
mMemFullThreshold = sm.getStorageFullBytes(DATA_PATH);
mMemCacheStartTrimThreshold = ((mMemLowThreshold*3)+mMemFullThreshold)/4;
mMemCacheTrimToThreshold = mMemLowThreshold
+ ((mMemLowThreshold-mMemCacheStartTrimThreshold)*2);
mFreeMemAfterLastCacheClear = mTotalMemory;
checkMemory(true);
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根據(jù) checkMemory 確認(rèn) mMemLowThreshold 是我們要找的閾值目標(biāo)
private final void checkMemory(boolean checkCache) {
//if the thread that was started to clear cache is still running do nothing till its
//finished clearing cache. Ideally this flag could be modified by clearCache
// and should be accessed via a lock but even if it does this test will fail now and
//hopefully the next time this flag will be set to the correct value.
if(mClearingCache) {
//......
} else {
restatDataDir();
if (localLOGV) Slog.v(TAG, "freeMemory="+mFreeMem);
//post intent to NotificationManager to display icon if necessary
if (mFreeMem < mMemLowThreshold) {
if (checkCache) {
// We are allowed to clear cache files at this point to
// try to get down below the limit, because this is not
// the initial call after a cache clear has been attempted.
// In this case we will try a cache clear if our free
// space has gone below the cache clear limit.
if (mFreeMem < mMemCacheStartTrimThreshold) {
// We only clear the cache if the free storage has changed
// a significant amount since the last time.
if ((mFreeMemAfterLastCacheClear-mFreeMem)
>= ((mMemLowThreshold-mMemCacheStartTrimThreshold)/4)) {
// See if clearing cache helps
// Note that clearing cache is asynchronous and so we do a
// memory check again once the cache has been cleared.
mThreadStartTime = System.currentTimeMillis();
mClearSucceeded = false;
clearCache();
}
}
} else {
// This is a call from after clearing the cache. Note
// the amount of free storage at this point.
mFreeMemAfterLastCacheClear = mFreeMem;
if (!mLowMemFlag) {
// We tried to clear the cache, but that didn't get us
// below the low storage limit. Tell the user.
Slog.i(TAG, "Running low on memory. Sending notification");
sendNotification();
mLowMemFlag = true;
} else {
if (localLOGV) Slog.v(TAG, "Running low on memory " +
"notification already sent. do nothing");
}
}
} else {
//......
}
if(localLOGV) Slog.i(TAG, "Posting Message again");
//keep posting messages to itself periodically
postCheckMemoryMsg(true, DEFAULT_CHECK_INTERVAL);
}
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找到 StorageManager.java
\frameworks\base\core\java\android\os\storage\StorageManager.java
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找到 getStorageLowBytes 函數(shù)
private static final int DEFAULT_THRESHOLD_PERCENTAGE = 10;
private static final long DEFAULT_THRESHOLD_MAX_BYTES = 500 * MB_IN_BYTES;
private static final long DEFAULT_FULL_THRESHOLD_BYTES = MB_IN_BYTES;
public long getStorageLowBytes(File path) {
final long lowPercent = Settings.Global.getInt(mResolver,
Settings.Global.SYS_STORAGE_THRESHOLD_PERCENTAGE, DEFAULT_THRESHOLD_PERCENTAGE);
final long lowBytes = (path.getTotalSpace() * lowPercent) / 100;
final long maxLowBytes = Settings.Global.getLong(mResolver,
Settings.Global.SYS_STORAGE_THRESHOLD_MAX_BYTES, DEFAULT_THRESHOLD_MAX_BYTES);
return Math.min(lowBytes, maxLowBytes);
}
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確認(rèn)目標(biāo)
- 總存儲空間的10%或500M中較小的那一個
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找到系統(tǒng)判定空間可用空間較低的閾值后慈缔，根據(jù)之前的錯誤提示信息 INSTALL_FAILED_INSUFFICIENT_STORAGE 叮称，定位問題
if (ret == PackageManager.INSTALL_SUCCEEDED) {
int loc = pkgLite.recommendedInstallLocation;
if (loc == PackageHelper.RECOMMEND_FAILED_INVALID_LOCATION) {
//......
} else if (loc == PackageHelper.RECOMMEND_FAILED_INSUFFICIENT_STORAGE) {
ret = PackageManager.INSTALL_FAILED_INSUFFICIENT_STORAGE;
} else if (loc == PackageHelper.RECOMMEND_FAILED_INVALID_APK) {
//......
}
}
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再找到loc的聲明
pkgLite = mContainerService.getMinimalPackageInfo(packageFilePath, flags, lowThreshold)int loc = pkgLite.recommendedInstallLocation可以看出下一步需要找到 getMinimalPackageInfo 的聲明
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經(jīng)過一番查找，在 DefaultContainerService.java 中找到其聲明
frameworks\base\packages\DefaultContainerService\src\com\android\defcontainer\DefaultContainerService.java
public PackageInfoLite getMinimalPackageInfo(final String packagePath, int flags,
long threshold) {
PackageInfoLite ret = new PackageInfoLite();
//...
ret.recommendedInstallLocation = recommendAppInstallLocation(pkg.installLocation,
packagePath, flags, threshold);
return ret;
}
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找到 recommendedInstallLocation 的聲明
private int recommendAppInstallLocation(int installLocation, String archiveFilePath, int flags,
long threshold) {
int prefer;
boolean checkBoth = false;
final boolean isForwardLocked = (flags & PackageManager.INSTALL_FORWARD_LOCK) != 0;
//......
final boolean emulated = Environment.isExternalStorageEmulated();
final File apkFile = new File(archiveFilePath);
boolean fitsOnInternal = false;
if (checkBoth || prefer == PREFER_INTERNAL) {
try {
fitsOnInternal = isUnderInternalThreshold(apkFile, isForwardLocked, threshold);
} catch (IOException e) {
return PackageHelper.RECOMMEND_FAILED_INVALID_URI;
}
}
boolean fitsOnSd = false;
if (!emulated && (checkBoth || prefer == PREFER_EXTERNAL)) {
try {
fitsOnSd = isUnderExternalThreshold(apkFile, isForwardLocked);
} catch (IOException e) {
return PackageHelper.RECOMMEND_FAILED_INVALID_URI;
}
}
if (prefer == PREFER_INTERNAL) {
if (fitsOnInternal) {
return PackageHelper.RECOMMEND_INSTALL_INTERNAL;
}
} else if (!emulated && prefer == PREFER_EXTERNAL) {
if (fitsOnSd) {
return PackageHelper.RECOMMEND_INSTALL_EXTERNAL;
}
}
if (checkBoth) {
if (fitsOnInternal) {
return PackageHelper.RECOMMEND_INSTALL_INTERNAL;
} else if (!emulated && fitsOnSd) {
return PackageHelper.RECOMMEND_INSTALL_EXTERNAL;
}
}
/*
* If they requested to be on the external media by default, return that
* the media was unavailable. Otherwise, indicate there was insufficient
* storage space available.
*/
if (!emulated && (checkBoth || prefer == PREFER_EXTERNAL)
&& !Environment.MEDIA_MOUNTED.equals(Environment.getExternalStorageState())) {
return PackageHelper.RECOMMEND_MEDIA_UNAVAILABLE;
} else {
return PackageHelper.RECOMMEND_FAILED_INSUFFICIENT_STORAGE;
}
}
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loc的關(guān)鍵返回判斷信息語句如下
if (!emulated && (checkBoth || prefer == PREFER_EXTERNAL)
&& !Environment.MEDIA_MOUNTED.equals(Environment.getExternalStorageState())) {
return PackageHelper.RECOMMEND_MEDIA_UNAVAILABLE;
} else {
return PackageHelper.RECOMMEND_FAILED_INSUFFICIENT_STORAGE;
}
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聯(lián)系前文藐鹤，依據(jù)判斷條件瓤檐，找到關(guān)鍵語句
fitsOnInternal = isUnderInternalThreshold(apkFile, isForwardLocked, threshold)
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尋找其聲明 isUnderInternalThreshold
private boolean isUnderInternalThreshold(File apkFile, boolean isForwardLocked, long threshold)
throws IOException {
long size = apkFile.length();
if (size == 0 && !apkFile.exists()) {
throw new FileNotFoundException();
}
if (isForwardLocked) {
size += PackageHelper.extractPublicFiles(apkFile.getAbsolutePath(), null);
}
final StatFs internalStats = new StatFs(Environment.getDataDirectory().getPath());
final long availInternalSize = (long) internalStats.getAvailableBlocks()
* (long) internalStats.getBlockSize();
return (availInternalSize - size) > threshold;
}
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從上面我們可以看出返回值為 可用空間—安裝大小>最低閾值
結(jié)論
- 我們終于做完了所有的事了,其結(jié)論就是：當(dāng)滿足 可用空間的大小 減去 安裝包需要的大小 大于 最低閾值(500M或存儲空間總大小的10%中的較小值) 的條件時，安裝才能進(jìn)行娱节。
后記
為了找出這個規(guī)定的閾值挠蛉，我查了不少文章，幾乎把安裝流程完全走了一遍肄满，可以說工作量非常巨大了谴古。并且一開始還成功地掉入了坑里，差點就把錯誤的結(jié)論拿出來講了稠歉。后來想想看好像不太對勁掰担，重新梳理了一遍邏輯才發(fā)現(xiàn)確實做錯了。不過走這一遍怒炸，雖然不知道有什么用带饱，但是相信也是積淀的一部分，希望在未來的日子里能夠讓我少踩一點坑横媚。
以下為有幫助的工具和參考文章
AndroidXRef 查源碼巨好用的網(wǎng)站
Android7.0 PackageManagerService
APK安裝流程詳解14——PMS中的新安裝流程上(拷貝)補(bǔ)充
