/*
* Copyright (C) 2009 The Android Open Source Project
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package com.android.server;
import android.content.BroadcastReceiver;
import android.content.ContentResolver;
import android.content.Context;
import android.content.Intent;
import android.content.IntentFilter;
import android.content.pm.PackageManager;
import android.database.ContentObserver;
import android.net.Uri;
import android.os.Binder;
import android.os.Debug;
import android.os.DropBoxManager;
import android.os.FileUtils;
import android.os.Handler;
import android.os.Message;
import android.os.StatFs;
import android.os.SystemClock;
import android.os.UserHandle;
import android.provider.Settings;
import android.text.format.Time;
import android.util.Slog;
import com.android.internal.os.IDropBoxManagerService;
import java.io.BufferedOutputStream;
import java.io.File;
import java.io.FileDescriptor;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.io.OutputStream;
import java.io.PrintWriter;
import java.util.ArrayList;
import java.util.HashMap;
import java.util.SortedSet;
import java.util.TreeSet;
import java.util.zip.GZIPOutputStream;
/**
* Implementation of {@link IDropBoxManagerService} using the filesystem.
* Clients use {@link DropBoxManager} to access this service.
*/
public final class DropBoxManagerService extends IDropBoxManagerService.Stub {
private static final String TAG = "DropBoxManagerService";
private static final int DEFAULT_AGE_SECONDS = 3 * 86400;
private static final int DEFAULT_MAX_FILES = 1000;
private static final int DEFAULT_QUOTA_KB = 5 * 1024;
private static final int DEFAULT_QUOTA_PERCENT = 10;
private static final int DEFAULT_RESERVE_PERCENT = 10;
private static final int QUOTA_RESCAN_MILLIS = 5000;
// mHandler 'what' value.
private static final int MSG_SEND_BROADCAST = 1;
private static final boolean PROFILE_DUMP = false;
// TODO: This implementation currently uses one file per entry, which is
// inefficient for smallish entries -- consider using a single queue file
// per tag (or even globally) instead.
// The cached context and derived objects
private final Context mContext;
private final ContentResolver mContentResolver;
private final File mDropBoxDir;
// Accounting of all currently written log files (set in init()).
private FileList mAllFiles = null;
private HashMap<String, FileList> mFilesByTag = null;
// Various bits of disk information
private StatFs mStatFs = null;
private int mBlockSize = 0;
private int mCachedQuotaBlocks = 0; // Space we can use: computed from free space, etc.
private long mCachedQuotaUptimeMillis = 0;
private volatile boolean mBooted = false;
// Provide a way to perform sendBroadcast asynchronously to avoid deadlocks.
private final Handler mHandler;
/** Receives events that might indicate a need to clean up files. */
private final BroadcastReceiver mReceiver = new BroadcastReceiver() {
@Override
public void onReceive(Context context, Intent intent) {
if (intent != null && Intent.ACTION_BOOT_COMPLETED.equals(intent.getAction())) {
mBooted = true;
return;
}
// Else, for ACTION_DEVICE_STORAGE_LOW:
mCachedQuotaUptimeMillis = 0; // Force a re-check of quota size
// Run the initialization in the background (not this main thread).
// The init() and trimToFit() methods are synchronized, so they still
// block other users -- but at least the onReceive() call can finish.
new Thread() {
public void run() {
try {
init();
trimToFit();
} catch (IOException e) {
Slog.e(TAG, "Can't init", e);
}
}
}.start();
}
};
/**
* Creates an instance of managed drop box storage. Normally there is one of these
* run by the system, but others can be created for testing and other purposes.
*
* @param context to use for receiving free space & gservices intents
* @param path to store drop box entries in
*/
public DropBoxManagerService(final Context context, File path) {
mDropBoxDir = path;
// Set up intent receivers
mContext = context;
mContentResolver = context.getContentResolver();
IntentFilter filter = new IntentFilter();
filter.addAction(Intent.ACTION_DEVICE_STORAGE_LOW);
filter.addAction(Intent.ACTION_BOOT_COMPLETED);
context.registerReceiver(mReceiver, filter);
mContentResolver.registerContentObserver(
Settings.Global.CONTENT_URI, true,
new ContentObserver(new Handler()) {
@Override
public void onChange(boolean selfChange) {
mReceiver.onReceive(context, (Intent) null);
}
});
mHandler = new Handler() {
@Override
public void handleMessage(Message msg) {
if (msg.what == MSG_SEND_BROADCAST) {
mContext.sendBroadcastAsUser((Intent)msg.obj, UserHandle.OWNER,
android.Manifest.permission.READ_LOGS);
}
}
};
// The real work gets done lazily in init() -- that way service creation always
// succeeds, and things like disk problems cause individual method failures.
}
/** Unregisters broadcast receivers and any other hooks -- for test instances */
public void stop() {
mContext.unregisterReceiver(mReceiver);
}
@Override
public void add(DropBoxManager.Entry entry) {
File temp = null;
OutputStream output = null;
final String tag = entry.getTag();
try {
int flags = entry.getFlags();
if ((flags & DropBoxManager.IS_EMPTY) != 0) throw new IllegalArgumentException();
init();
if (!isTagEnabled(tag)) return;
long max = trimToFit();
long lastTrim = System.currentTimeMillis();
byte[] buffer = new byte[mBlockSize];
InputStream input = entry.getInputStream();
// First, accumulate up to one block worth of data in memory before
// deciding whether to compress the data or not.
int read = 0;
while (read < buffer.length) {
int n = input.read(buffer, read, buffer.length - read);
if (n <= 0) break;
read += n;
}
// If we have at least one block, compress it -- otherwise, just write
// the data in uncompressed form.
temp = new File(mDropBoxDir, "drop" + Thread.currentThread().getId() + ".tmp");
int bufferSize = mBlockSize;
if (bufferSize > 4096) bufferSize = 4096;
if (bufferSize < 512) bufferSize = 512;
FileOutputStream foutput = new FileOutputStream(temp);
output = new BufferedOutputStream(foutput, bufferSize);
if (read == buffer.length && ((flags & DropBoxManager.IS_GZIPPED) == 0)) {
output = new GZIPOutputStream(output);
flags = flags | DropBoxManager.IS_GZIPPED;
}
do {
output.write(buffer, 0, read);
long now = System.currentTimeMillis();
if (now - lastTrim > 30 * 1000) {
max = trimToFit(); // In case data dribbles in slowly
lastTrim = now;
}
read = input.read(buffer);
if (read <= 0) {
FileUtils.sync(foutput);
output.close(); // Get a final size measurement
output = null;
} else {
output.flush(); // So the size measurement is pseudo-reasonable
}
long len = temp.length();
if (len > max) {
Slog.w(TAG, "Dropping: " + tag + " (" + temp.length() + " > " + max + " bytes)");
temp.delete();
temp = null; // Pass temp = null to createEntry() to leave a tombstone
break;
}
} while (read > 0);
long time = createEntry(temp, tag, flags);
temp = null;
final Intent dropboxIntent = new Intent(DropBoxManager.ACTION_DROPBOX_ENTRY_ADDED);
dropboxIntent.putExtra(DropBoxManager.EXTRA_TAG, tag);
dropboxIntent.putExtra(DropBoxManager.EXTRA_TIME, time);
if (!mBooted) {
dropboxIntent.addFlags(Intent.FLAG_RECEIVER_REGISTERED_ONLY);
}
// Call sendBroadcast after returning from this call to avoid deadlock. In particular
// the caller may be holding the WindowManagerService lock but sendBroadcast requires a
// lock in ActivityManagerService. ActivityManagerService has been caught holding that
// very lock while waiting for the WindowManagerService lock.
mHandler.sendMessage(mHandler.obtainMessage(MSG_SEND_BROADCAST, dropboxIntent));
} catch (IOException e) {
Slog.e(TAG, "Can't write: " + tag, e);
} finally {
try { if (output != null) output.close(); } catch (IOException e) {}
entry.close();
if (temp != null) temp.delete();
}
}
public boolean isTagEnabled(String tag) {
final long token = Binder.clearCallingIdentity();
try {
return !"disabled".equals(Settings.Global.getString(
mContentResolver, Settings.Global.DROPBOX_TAG_PREFIX + tag));
} finally {
Binder.restoreCallingIdentity(token);
}
}
public synchronized DropBoxManager.Entry getNextEntry(String tag, long millis) {
if (mContext.checkCallingOrSelfPermission(android.Manifest.permission.READ_LOGS)
!= PackageManager.PERMISSION_GRANTED) {
throw new SecurityException("READ_LOGS permission required");
}
try {
init();
} catch (IOException e) {
Slog.e(TAG, "Can't init", e);
return null;
}
FileList list = tag == null ? mAllFiles : mFilesByTag.get(tag);
if (list == null) return null;
for (EntryFile entry : list.contents.tailSet(new EntryFile(millis + 1))) {
if (entry.tag == null) continue;
if ((entry.flags & DropBoxManager.IS_EMPTY) != 0) {
return new DropBoxManager.Entry(entry.tag, entry.timestampMillis);
}
try {
return new DropBoxManager.Entry(
entry.tag, entry.timestampMillis, entry.file, entry.flags);
} catch (IOException e) {
Slog.e(TAG, "Can't read: " + entry.file, e);
// Continue to next file
}
}
return null;
}
public synchronized void dump(FileDescriptor fd, PrintWriter pw, String[] args) {
if (mContext.checkCallingOrSelfPermission(android.Manifest.permission.DUMP)
!= PackageManager.PERMISSION_GRANTED) {
pw.println("Permission Denial: Can't dump DropBoxManagerService");
return;
}
try {
init();
} catch (IOException e) {
pw.println("Can't initialize: " + e);
Slog.e(TAG, "Can't init", e);
return;
}
if (PROFILE_DUMP) Debug.startMethodTracing("/data/trace/dropbox.dump");
StringBuilder out = new StringBuilder();
boolean doPrint = false, doFile = false;
ArrayList<String> searchArgs = new ArrayList<String>();
for (int i = 0; args != null && i < args.length; i++) {
if (args[i].equals("-p") || args[i].equals("--print")) {
doPrint = true;
} else if (args[i].equals("-f") || args[i].equals("--file")) {
doFile = true;
} else if (args[i].startsWith("-")) {
out.append("Unknown argument: ").append(args[i]).append("\n");
} else {
searchArgs.add(args[i]);
}
}
out.append("Drop box contents: ").append(mAllFiles.contents.size()).append(" entries\n");
if (!searchArgs.isEmpty()) {
out.append("Searching for:");
for (String a : searchArgs) out.append(" ").append(a);
out.append("\n");
}
int numFound = 0, numArgs = searchArgs.size();
Time time = new Time();
out.append("\n");
for (EntryFile entry : mAllFiles.contents) {
time.set(entry.timestampMillis);
String date = time.format("%Y-%m-%d %H:%M:%S");
boolean match = true;
for (int i = 0; i < numArgs && match; i++) {
String arg = searchArgs.get(i);
match = (date.contains(arg) || arg.equals(entry.tag));
}
if (!match) continue;
numFound++;
if (doPrint) out.append("========================================\n");
out.append(date).append(" ").append(entry.tag == null ? "(no tag)" : entry.tag);
if (entry.file == null) {
out.append(" (no file)\n");
continue;
} else if ((entry.flags & DropBoxManager.IS_EMPTY) != 0) {
out.append(" (contents lost)\n");
continue;
} else {
out.append(" (");
if ((entry.flags & DropBoxManager.IS_GZIPPED) != 0) out.append("compressed ");
out.append((entry.flags & DropBoxManager.IS_TEXT) != 0 ? "text" : "data");
out.append(", ").append(entry.file.length()).append(" bytes)\n");
}
if (doFile || (doPrint && (entry.flags & DropBoxManager.IS_TEXT) == 0)) {
if (!doPrint) out.append(" ");
out.append(entry.file.getPath()).append("\n");
}
if ((entry.flags & DropBoxManager.IS_TEXT) != 0 && (doPrint || !doFile)) {
DropBoxManager.Entry dbe = null;
InputStreamReader isr = null;
try {
dbe = new DropBoxManager.Entry(
entry.tag, entry.timestampMillis, entry.file, entry.flags);
if (doPrint) {
isr = new InputStreamReader(dbe.getInputStream());
char[] buf = new char[4096];
boolean newline = false;
for (;;) {
int n = isr.read(buf);
if (n <= 0) break;
out.append(buf, 0, n);
newline = (buf[n - 1] == '\n');
// Flush periodically when printing to avoid out-of-memory.
if (out.length() > 65536) {
pw.write(out.toString());
out.setLength(0);
}
}
if (!newline) out.append("\n");
} else {
String text = dbe.getText(70);
out.append(" ");
if (text == null) {
out.append("[null]");
} else {
boolean truncated = (text.length() == 70);
out.append(text.trim().replace('\n', '/'));
if (truncated) out.append(" ...");
}
out.append("\n");
}
} catch (IOException e) {
out.append("*** ").append(e.toString()).append("\n");
Slog.e(TAG, "Can't read: " + entry.file, e);
} finally {
if (dbe != null) dbe.close();
if (isr != null) {
try {
isr.close();
} catch (IOException unused) {
}
}
}
}
if (doPrint) out.append("\n");
}
if (numFound == 0) out.append("(No entries found.)\n");
if (args == null || args.length == 0) {
if (!doPrint) out.append("\n");
out.append("Usage: dumpsys dropbox [--print|--file] [YYYY-mm-dd] [HH:MM:SS] [tag]\n");
}
pw.write(out.toString());
if (PROFILE_DUMP) Debug.stopMethodTracing();
}
///////////////////////////////////////////////////////////////////////////
/** Chronologically sorted list of {@link #EntryFile} */
private static final class FileList implements Comparable<FileList> {
public int blocks = 0;
public final TreeSet<EntryFile> contents = new TreeSet<EntryFile>();
/** Sorts bigger FileList instances before smaller ones. */
public final int compareTo(FileList o) {
if (blocks != o.blocks) return o.blocks - blocks;
if (this == o) return 0;
if (hashCode() < o.hashCode()) return -1;
if (hashCode() > o.hashCode()) return 1;
return 0;
}
}
/** Metadata describing an on-disk log file. */
private static final class EntryFile implements Comparable<EntryFile> {
public final String tag;
public final long timestampMillis;
public final int flags;
public final File file;
public final int blocks;
/** Sorts earlier EntryFile instances before later ones. */
public final int compareTo(EntryFile o) {
if (timestampMillis < o.timestampMillis) return -1;
if (timestampMillis > o.timestampMillis) return 1;
if (file != null && o.file != null) return file.compareTo(o.file);
if (o.file != null) return -1;
if (file != null) return 1;
if (this == o) return 0;
if (hashCode() < o.hashCode()) return -1;
if (hashCode() > o.hashCode()) return 1;
return 0;
}
/**
* Moves an existing temporary file to a new log filename.
* @param temp file to rename
* @param dir to store file in
* @param tag to use for new log file name
* @param timestampMillis of log entry
* @param flags for the entry data
* @param blockSize to use for space accounting
* @throws IOException if the file can't be moved
*/
public EntryFile(File temp, File dir, String tag,long timestampMillis,
int flags, int blockSize) throws IOException {
if ((flags & DropBoxManager.IS_EMPTY) != 0) throw new IllegalArgumentException();
this.tag = tag;
this.timestampMillis = timestampMillis;
this.flags = flags;
this.file = new File(dir, Uri.encode(tag) + "@" + timestampMillis +
((flags & DropBoxManager.IS_TEXT) != 0 ? ".txt" : ".dat") +
((flags & DropBoxManager.IS_GZIPPED) != 0 ? ".gz" : ""));
if (!temp.renameTo(this.file)) {
throw new IOException("Can't rename " + temp + " to " + this.file);
}
this.blocks = (int) ((this.file.length() + blockSize - 1) / blockSize);
}
/**
* Creates a zero-length tombstone for a file whose contents were lost.
* @param dir to store file in
* @param tag to use for new log file name
* @param timestampMillis of log entry
* @throws IOException if the file can't be created.
*/
public EntryFile(File dir, String tag, long timestampMillis) throws IOException {
this.tag = tag;
this.timestampMillis = timestampMillis;
this.flags = DropBoxManager.IS_EMPTY;
this.file = new File(dir, Uri.encode(tag) + "@" + timestampMillis + ".lost");
this.blocks = 0;
new FileOutputStream(this.file).close();
}
/**
* Extracts metadata from an existing on-disk log filename.
* @param file name of existing log file
* @param blockSize to use for space accounting
*/
public EntryFile(File file, int blockSize) {
this.file = file;
this.blocks = (int) ((this.file.length() + blockSize - 1) / blockSize);
String name = file.getName();
int at = name.lastIndexOf('@');
if (at < 0) {
this.tag = null;
this.timestampMillis = 0;
this.flags = DropBoxManager.IS_EMPTY;
return;
}
int flags = 0;
this.tag = Uri.decode(name.substring(0, at));
if (name.endsWith(".gz")) {
flags |= DropBoxManager.IS_GZIPPED;
name = name.substring(0, name.length() - 3);
}
if (name.endsWith(".lost")) {
flags |= DropBoxManager.IS_EMPTY;
name = name.substring(at + 1, name.length() - 5);
} else if (name.endsWith(".txt")) {
flags |= DropBoxManager.IS_TEXT;
name = name.substring(at + 1, name.length() - 4);
} else if (name.endsWith(".dat")) {
name = name.substring(at + 1, name.length() - 4);
} else {
this.flags = DropBoxManager.IS_EMPTY;
this.timestampMillis = 0;
return;
}
this.flags = flags;
long millis;
try { millis = Long.valueOf(name); } catch (NumberFormatException e) { millis = 0; }
this.timestampMillis = millis;
}
/**
* Creates a EntryFile object with only a timestamp for comparison purposes.
* @param timestampMillis to compare with.
*/
public EntryFile(long millis) {
this.tag = null;
this.timestampMillis = millis;
this.flags = DropBoxManager.IS_EMPTY;
this.file = null;
this.blocks = 0;
}
}
///////////////////////////////////////////////////////////////////////////
/** If never run before, scans disk contents to build in-memory tracking data. */
private synchronized void init() throws IOException {
if (mStatFs == null) {
if (!mDropBoxDir.isDirectory() && !mDropBoxDir.mkdirs()) {
throw new IOException("Can't mkdir: " + mDropBoxDir);
}
try {
mStatFs = new StatFs(mDropBoxDir.getPath());
mBlockSize = mStatFs.getBlockSize();
} catch (IllegalArgumentException e) { // StatFs throws this on error
throw new IOException("Can't statfs: " + mDropBoxDir);
}
}
if (mAllFiles == null) {
File[] files = mDropBoxDir.listFiles();
if (files == null) throw new IOException("Can't list files: " + mDropBoxDir);
mAllFiles = new FileList();
mFilesByTag = new HashMap<String, FileList>();
// Scan pre-existing files.
for (File file : files) {
if (file.getName().endsWith(".tmp")) {
Slog.i(TAG, "Cleaning temp file: " + file);
file.delete();
continue;
}
EntryFile entry = new EntryFile(file, mBlockSize);
if (entry.tag == null) {
Slog.w(TAG, "Unrecognized file: " + file);
continue;
} else if (entry.timestampMillis == 0) {
Slog.w(TAG, "Invalid filename: " + file);
file.delete();
continue;
}
enrollEntry(entry);
}
}
}
/** Adds a disk log file to in-memory tracking for accounting and enumeration. */
private synchronized void enrollEntry(EntryFile entry) {
mAllFiles.contents.add(entry);
mAllFiles.blocks += entry.blocks;
// mFilesByTag is used for trimming, so don't list empty files.
// (Zero-length/lost files are trimmed by date from mAllFiles.)
if (entry.tag != null && entry.file != null && entry.blocks > 0) {
FileList tagFiles = mFilesByTag.get(entry.tag);
if (tagFiles == null) {
tagFiles = new FileList();
mFilesByTag.put(entry.tag, tagFiles);
}
tagFiles.contents.add(entry);
tagFiles.blocks += entry.blocks;
}
}
/** Moves a temporary file to a final log filename and enrolls it. */
private synchronized long createEntry(File temp, String tag, int flags) throws IOException {
long t = System.currentTimeMillis();
// Require each entry to have a unique timestamp; if there are entries
// >10sec in the future (due to clock skew), drag them back to avoid
// keeping them around forever.
SortedSet<EntryFile> tail = mAllFiles.contents.tailSet(new EntryFile(t + 10000));
EntryFile[] future = null;
if (!tail.isEmpty()) {
future = tail.toArray(new EntryFile[tail.size()]);
tail.clear(); // Remove from mAllFiles
}
if (!mAllFiles.contents.isEmpty()) {
t = Math.max(t, mAllFiles.contents.last().timestampMillis + 1);
}
if (future != null) {
for (EntryFile late : future) {
mAllFiles.blocks -= late.blocks;
FileList tagFiles = mFilesByTag.get(late.tag);
if (tagFiles != null && tagFiles.contents.remove(late)) {
tagFiles.blocks -= late.blocks;
}
if ((late.flags & DropBoxManager.IS_EMPTY) == 0) {
enrollEntry(new EntryFile(
late.file, mDropBoxDir, late.tag, t++, late.flags, mBlockSize));
} else {
enrollEntry(new EntryFile(mDropBoxDir, late.tag, t++));
}
}
}
if (temp == null) {
enrollEntry(new EntryFile(mDropBoxDir, tag, t));
} else {
enrollEntry(new EntryFile(temp, mDropBoxDir, tag, t, flags, mBlockSize));
}
return t;
}
/**
* Trims the files on disk to make sure they aren't using too much space.
* @return the overall quota for storage (in bytes)
*/
private synchronized long trimToFit() {
// Expunge aged items (including tombstones marking deleted data).
int ageSeconds = Settings.Global.getInt(mContentResolver,
Settings.Global.DROPBOX_AGE_SECONDS, DEFAULT_AGE_SECONDS);
int maxFiles = Settings.Global.getInt(mContentResolver,
Settings.Global.DROPBOX_MAX_FILES, DEFAULT_MAX_FILES);
long cutoffMillis = System.currentTimeMillis() - ageSeconds * 1000;
while (!mAllFiles.contents.isEmpty()) {
EntryFile entry = mAllFiles.contents.first();
if (entry.timestampMillis > cutoffMillis && mAllFiles.contents.size() < maxFiles) break;
FileList tag = mFilesByTag.get(entry.tag);
if (tag != null && tag.contents.remove(entry)) tag.blocks -= entry.blocks;
if (mAllFiles.contents.remove(entry)) mAllFiles.blocks -= entry.blocks;
if (entry.file != null) entry.file.delete();
}
// Compute overall quota (a fraction of available free space) in blocks.
// The quota changes dynamically based on the amount of free space;
// that way when lots of data is available we can use it, but we'll get
// out of the way if storage starts getting tight.
long uptimeMillis = SystemClock.uptimeMillis();
if (uptimeMillis > mCachedQuotaUptimeMillis + QUOTA_RESCAN_MILLIS) {
int quotaPercent = Settings.Global.getInt(mContentResolver,
Settings.Global.DROPBOX_QUOTA_PERCENT, DEFAULT_QUOTA_PERCENT);
int reservePercent = Settings.Global.getInt(mContentResolver,
Settings.Global.DROPBOX_RESERVE_PERCENT, DEFAULT_RESERVE_PERCENT);
int quotaKb = Settings.Global.getInt(mContentResolver,
Settings.Global.DROPBOX_QUOTA_KB, DEFAULT_QUOTA_KB);
mStatFs.restat(mDropBoxDir.getPath());
int available = mStatFs.getAvailableBlocks();
int nonreserved = available - mStatFs.getBlockCount() * reservePercent / 100;
int maximum = quotaKb * 1024 / mBlockSize;
mCachedQuotaBlocks = Math.min(maximum, Math.max(0, nonreserved * quotaPercent / 100));
mCachedQuotaUptimeMillis = uptimeMillis;
}
// If we're using too much space, delete old items to make room.
//
// We trim each tag independently (this is why we keep per-tag lists).
// Space is "fairly" shared between tags -- they are all squeezed
// equally until enough space is reclaimed.
//
// A single circular buffer (a la logcat) would be simpler, but this
// way we can handle fat/bursty data (like 1MB+ bugreports, 300KB+
// kernel crash dumps, and 100KB+ ANR reports) without swamping small,
// well-behaved data streams (event statistics, profile data, etc).
//
// Deleted files are replaced with zero-length tombstones to mark what
// was lost. Tombstones are expunged by age (see above).
if (mAllFiles.blocks > mCachedQuotaBlocks) {
// Find a fair share amount of space to limit each tag
int unsqueezed = mAllFiles.blocks, squeezed = 0;
TreeSet<FileList> tags = new TreeSet<FileList>(mFilesByTag.values());
for (FileList tag : tags) {
if (squeezed > 0 && tag.blocks <= (mCachedQuotaBlocks - unsqueezed) / squeezed) {
break;
}
unsqueezed -= tag.blocks;
squeezed++;
}
int tagQuota = (mCachedQuotaBlocks - unsqueezed) / squeezed;
// Remove old items from each tag until it meets the per-tag quota.
for (FileList tag : tags) {
if (mAllFiles.blocks < mCachedQuotaBlocks) break;
while (tag.blocks > tagQuota && !tag.contents.isEmpty()) {
EntryFile entry = tag.contents.first();
if (tag.contents.remove(entry)) tag.blocks -= entry.blocks;
if (mAllFiles.contents.remove(entry)) mAllFiles.blocks -= entry.blocks;
try {
if (entry.file != null) entry.file.delete();
enrollEntry(new EntryFile(mDropBoxDir, entry.tag, entry.timestampMillis));
} catch (IOException e) {
Slog.e(TAG, "Can't write tombstone file", e);
}
}
}
}
return mCachedQuotaBlocks * mBlockSize;
}
}
|
