Back up wallpapers via staged copies, not hard links (b58e460c) · Commits · e / os / android_frameworks_base

packages/WallpaperBackup/src/com/android/wallpaperbackup/WallpaperBackupAgent.java

+49 −22

Original line number	Diff line number	Diff line
		@@ -16,17 +16,21 @@

		package com.android.wallpaperbackup;

		import static android.app.WallpaperManager.FLAG_LOCK;
		import static android.app.WallpaperManager.FLAG_SYSTEM;

		import android.app.WallpaperManager;
		import android.app.backup.BackupAgent;
		import android.app.backup.BackupDataInput;
		import android.app.backup.BackupDataOutput;
		import android.app.backup.FullBackupDataOutput;
		import android.content.Context;
		import android.content.SharedPreferences;
		import android.graphics.Rect;
		import android.os.Environment;
		import android.os.FileUtils;
		import android.os.ParcelFileDescriptor;
		import android.os.UserHandle;
		import android.system.Os;
		import android.util.Slog;
		import android.util.Xml;

		@@ -40,7 +44,7 @@ import java.nio.charset.StandardCharsets;

		public class WallpaperBackupAgent extends BackupAgent {
		private static final String TAG = "WallpaperBackup";
		private static final boolean DEBUG = true;
		private static final boolean DEBUG = false;

		// NB: must be kept in sync with WallpaperManagerService but has no
		// compile-time visibility.
		@@ -57,6 +61,11 @@ public class WallpaperBackupAgent extends BackupAgent {
		static final String EMPTY_SENTINEL = "empty";
		static final String QUOTA_SENTINEL = "quota";

		// Not-for-backup bookkeeping
		static final String PREFS_NAME = "wbprefs.xml";
		static final String SYSTEM_GENERATION = "system_gen";
		static final String LOCK_GENERATION = "lock_gen";

		private File mWallpaperInfo; // wallpaper metadata file
		private File mWallpaperFile; // primary wallpaper image file
		private File mLockWallpaperFile; // lock wallpaper image file
		@@ -106,27 +115,48 @@ public class WallpaperBackupAgent extends BackupAgent {
		// only back up the wallpaper if we've been told it's allowed
		if (mWm.isWallpaperBackupEligible()) {
		if (DEBUG) {
		Slog.v(TAG, "Wallpaper is backup-eligible; linking & writing");
		Slog.v(TAG, "Wallpaper is backup-eligible");
		}

		// In case of prior muddled state
		infoStage.delete();
		imageStage.delete();
		lockImageStage.delete();
		SharedPreferences prefs = getSharedPreferences(PREFS_NAME, Context.MODE_PRIVATE);
		final int lastSysGeneration = prefs.getInt(SYSTEM_GENERATION, -1);
		final int lastLockGeneration = prefs.getInt(LOCK_GENERATION, -1);

		final int sysGeneration =
		mWm.getWallpaperIdForUser(FLAG_SYSTEM, UserHandle.USER_SYSTEM);
		final int lockGeneration =
		mWm.getWallpaperIdForUser(FLAG_LOCK, UserHandle.USER_SYSTEM);
		final boolean sysChanged = (sysGeneration != lastSysGeneration);
		final boolean lockChanged = (lockGeneration != lastLockGeneration);

		if (DEBUG) {
		Slog.v(TAG, "sysGen=" + sysGeneration + " : sysChanged=" + sysChanged);
		Slog.v(TAG, "lockGen=" + lockGeneration + " : lockChanged=" + lockChanged);
		}
		if (mWallpaperInfo.exists()) {
		Os.link(mWallpaperInfo.getCanonicalPath(), infoStage.getCanonicalPath());
		if (sysChanged \|\| lockChanged \|\| !infoStage.exists()) {
		if (DEBUG) Slog.v(TAG, "New wallpaper configuration; copying");
		FileUtils.copyFileOrThrow(mWallpaperInfo, infoStage);
		}
		fullBackupFile(infoStage, data);
		}
		if (mWallpaperFile.exists()) {
		Os.link(mWallpaperFile.getCanonicalPath(), imageStage.getCanonicalPath());
		if (sysChanged \|\| !imageStage.exists()) {
		if (DEBUG) Slog.v(TAG, "New system wallpaper; copying");
		FileUtils.copyFileOrThrow(mWallpaperFile, imageStage);
		}
		fullBackupFile(imageStage, data);
		prefs.edit().putInt(SYSTEM_GENERATION, sysGeneration).apply();
		}

		// Don't try to store the lock image if we overran our quota last time
		if (mLockWallpaperFile.exists() && !mQuotaExceeded) {
		Os.link(mLockWallpaperFile.getCanonicalPath(), lockImageStage.getCanonicalPath());
		if (lockChanged \|\| !lockImageStage.exists()) {
		if (DEBUG) Slog.v(TAG, "New lock wallpaper; copying");
		FileUtils.copyFileOrThrow(mLockWallpaperFile, lockImageStage);
		}
		fullBackupFile(lockImageStage, data);
		prefs.edit().putInt(LOCK_GENERATION, lockGeneration).apply();
		}
		} else {
		if (DEBUG) {
		@@ -136,13 +166,6 @@ public class WallpaperBackupAgent extends BackupAgent {
		} catch (Exception e) {
		Slog.e(TAG, "Unable to back up wallpaper", e);
		} finally {
		if (DEBUG) {
		Slog.v(TAG, "Removing backup stage links");
		}
		infoStage.delete();
		imageStage.delete();
		lockImageStage.delete();

		// Even if this time we had to back off on attempting to store the lock image
		// due to exceeding the data quota, try again next time. This will alternate
		// between "try both" and "only store the primary image" until either there
		@@ -189,26 +212,30 @@ public class WallpaperBackupAgent extends BackupAgent {
		Slog.e(TAG, "Unable to restore wallpaper: " + e.getMessage());
		} finally {
		if (DEBUG) {
		Slog.v(TAG, "Removing restore stage files");
		Slog.v(TAG, "Restore finished; clearing backup bookkeeping");
		}
		infoStage.delete();
		imageStage.delete();
		lockImageStage.delete();

		SharedPreferences prefs = getSharedPreferences(PREFS_NAME, Context.MODE_PRIVATE);
		prefs.edit()
		.putInt(SYSTEM_GENERATION, -1)
		.putInt(LOCK_GENERATION, -1)
		.commit();
		}
		}

		private void restoreFromStage(File stage, File info, String hintTag, int which)
		throws IOException {
		if (stage.exists()) {
		if (DEBUG) {
		Slog.v(TAG, "Got restored wallpaper; applying which=" + which);
		}
		// Parse the restored info file to find the crop hint. Note that this currently
		// relies on a priori knowledge of the wallpaper info file schema.
		Rect cropHint = parseCropHint(info, hintTag);
		if (cropHint != null) {
		Slog.i(TAG, "Got restored wallpaper; applying which=" + which);
		if (DEBUG) {
		Slog.v(TAG, "Restored crop hint " + cropHint + "; now writing data");
		Slog.v(TAG, "Restored crop hint " + cropHint);
		}
		try (FileInputStream in = new FileInputStream(stage)) {
		mWm.setStream(in, cropHint, true, which);