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Merge "Make getSharedPreference() async, blocking on first access."

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This commit is contained in:
Brad Fitzpatrick
2010-12-07 11:02:45 -08:00
committed by Android (Google) Code Review
parent 5151b325a4 4cd50b8d76
commit c5448ba75f
2 changed files with 115 additions and 74 deletions
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51
core/java/android/app/ContextImpl.java
View File

@@ -532,10 +532,6 @@ class ContextImpl extends Context {
throw new RuntimeException("Not supported in system context");
}
static File makeBackupFile(File prefsFile) {
return new File(prefsFile.getPath() + ".bak");
}
public File getSharedPrefsFile(String name) {
return makeFilename(getPreferencesDir(), name + ".xml");
}
@@ -543,54 +539,19 @@ class ContextImpl extends Context {
@Override
public SharedPreferences getSharedPreferences(String name, int mode) {
SharedPreferencesImpl sp;
File prefsFile;
boolean needInitialLoad = false;
synchronized (sSharedPrefs) {
sp = sSharedPrefs.get(name);
if (sp != null && !sp.hasFileChangedUnexpectedly()) {
return sp;
}
prefsFile = getSharedPrefsFile(name);
if (sp == null) {
sp = new SharedPreferencesImpl(prefsFile, mode, null);
File prefsFile = getSharedPrefsFile(name);
sp = new SharedPreferencesImpl(prefsFile, mode);
sSharedPrefs.put(name, sp);
needInitialLoad = true;
}
}
synchronized (sp) {
if (needInitialLoad && sp.isLoaded()) {
// lost the race to load; another thread handled it
return sp;
}
File backup = makeBackupFile(prefsFile);
if (backup.exists()) {
prefsFile.delete();
backup.renameTo(prefsFile);
}
// Debugging
if (prefsFile.exists() && !prefsFile.canRead()) {
Log.w(TAG, "Attempt to read preferences file " + prefsFile + " without permission");
}
Map map = null;
FileStatus stat = new FileStatus();
if (FileUtils.getFileStatus(prefsFile.getPath(), stat) && prefsFile.canRead()) {
try {
FileInputStream str = new FileInputStream(prefsFile);
map = XmlUtils.readMapXml(str);
str.close();
} catch (XmlPullParserException e) {
Log.w(TAG, "getSharedPreferences", e);
} catch (FileNotFoundException e) {
Log.w(TAG, "getSharedPreferences", e);
} catch (IOException e) {
Log.w(TAG, "getSharedPreferences", e);
}
}
sp.replace(map, stat);
}
// If somebody else (some other process) changed the prefs
// file behind our back, we reload it. This has been the
// historical (if undocumented) behavior.
sp.startReloadIfChangedUnexpectedly();
return sp;
}

138
core/java/android/app/SharedPreferencesImpl.java
View File

@@ -25,9 +25,12 @@ import android.util.Log;
import com.google.android.collect.Maps;
import com.android.internal.util.XmlUtils;
import dalvik.system.BlockGuard;
import org.xmlpull.v1.XmlPullParserException;
import java.io.File;
import java.io.FileInputStream;
import java.io.FileNotFoundException;
import java.io.FileOutputStream;
import java.io.IOException;
@@ -61,32 +64,88 @@ final class SharedPreferencesImpl implements SharedPreferences {
private final Object mWritingToDiskLock = new Object();
private static final Object mContent = new Object();
private final WeakHashMap<OnSharedPreferenceChangeListener, Object> mListeners;
private final WeakHashMap<OnSharedPreferenceChangeListener, Object> mListeners =
new WeakHashMap<OnSharedPreferenceChangeListener, Object>();
SharedPreferencesImpl(
File file, int mode, Map initialContents) {
SharedPreferencesImpl(File file, int mode) {
mFile = file;
mBackupFile = ContextImpl.makeBackupFile(file);
mBackupFile = makeBackupFile(file);
mMode = mode;
mLoaded = initialContents != null;
mMap = initialContents != null ? initialContents : new HashMap<String, Object>();
FileStatus stat = new FileStatus();
if (FileUtils.getFileStatus(file.getPath(), stat)) {
mStatTimestamp = stat.mtime;
}
mListeners = new WeakHashMap<OnSharedPreferenceChangeListener, Object>();
mLoaded = false;
mMap = null;
startLoadFromDisk();
}
// Has this SharedPreferences ever had values assigned to it?
boolean isLoaded() {
private void startLoadFromDisk() {
synchronized (this) {
return mLoaded;
mLoaded = false;
}
new Thread("SharedPreferencesImpl-load") {
public void run() {
synchronized (SharedPreferencesImpl.this) {
loadFromDiskLocked();
}
}
}.start();
}
private void loadFromDiskLocked() {
if (mLoaded) {
return;
}
if (mBackupFile.exists()) {
mFile.delete();
mBackupFile.renameTo(mFile);
}
// Debugging
if (mFile.exists() && !mFile.canRead()) {
Log.w(TAG, "Attempt to read preferences file " + mFile + " without permission");
}
Map map = null;
FileStatus stat = new FileStatus();
if (FileUtils.getFileStatus(mFile.getPath(), stat) && mFile.canRead()) {
try {
FileInputStream str = new FileInputStream(mFile);
map = XmlUtils.readMapXml(str);
str.close();
} catch (XmlPullParserException e) {
Log.w(TAG, "getSharedPreferences", e);
} catch (FileNotFoundException e) {
Log.w(TAG, "getSharedPreferences", e);
} catch (IOException e) {
Log.w(TAG, "getSharedPreferences", e);
}
}
mLoaded = true;
if (map != null) {
mMap = map;
mStatTimestamp = stat.mtime;
mStatSize = stat.size;
} else {
mMap = new HashMap<String, Object>();
}
notifyAll();
}
private static File makeBackupFile(File prefsFile) {
return new File(prefsFile.getPath() + ".bak");
}
void startReloadIfChangedUnexpectedly() {
synchronized (this) {
// TODO: wait for any pending writes to disk?
if (!hasFileChangedUnexpectedly()) {
return;
}
startLoadFromDisk();
}
}
// Has the file changed out from under us? i.e. writes that
// we didn't instigate.
public boolean hasFileChangedUnexpectedly() {
private boolean hasFileChangedUnexpectedly() {
synchronized (this) {
if (mDiskWritesInFlight > 0) {
// If we know we caused it, it's not unexpected.
@@ -103,19 +162,6 @@ final class SharedPreferencesImpl implements SharedPreferences {
}
}
/*package*/ void replace(Map newContents, FileStatus stat) {
synchronized (this) {
mLoaded = true;
if (newContents != null) {
mMap = newContents;
}
if (stat != null) {
mStatTimestamp = stat.mtime;
mStatSize = stat.size;
}
}
}
public void registerOnSharedPreferenceChangeListener(OnSharedPreferenceChangeListener listener) {
synchronized(this) {
mListeners.put(listener, mContent);
@@ -128,8 +174,24 @@ final class SharedPreferencesImpl implements SharedPreferences {
}
}
private void awaitLoadedLocked() {
if (!mLoaded) {
// Raise an explicit StrictMode onReadFromDisk for this
// thread, since the real read will be in a different
// thread and otherwise ignored by StrictMode.
BlockGuard.getThreadPolicy().onReadFromDisk();
}
while (!mLoaded) {
try {
wait();
} catch (InterruptedException unused) {
}
}
}
public Map<String, ?> getAll() {
synchronized(this) {
synchronized (this) {
awaitLoadedLocked();
//noinspection unchecked
return new HashMap<String, Object>(mMap);
}
@@ -137,6 +199,7 @@ final class SharedPreferencesImpl implements SharedPreferences {
public String getString(String key, String defValue) {
synchronized (this) {
awaitLoadedLocked();
String v = (String)mMap.get(key);
return v != null ? v : defValue;
}
@@ -144,6 +207,7 @@ final class SharedPreferencesImpl implements SharedPreferences {
public Set<String> getStringSet(String key, Set<String> defValues) {
synchronized (this) {
awaitLoadedLocked();
Set<String> v = (Set<String>) mMap.get(key);
return v != null ? v : defValues;
}
@@ -151,24 +215,28 @@ final class SharedPreferencesImpl implements SharedPreferences {
public int getInt(String key, int defValue) {
synchronized (this) {
awaitLoadedLocked();
Integer v = (Integer)mMap.get(key);
return v != null ? v : defValue;
}
}
public long getLong(String key, long defValue) {
synchronized (this) {
awaitLoadedLocked();
Long v = (Long)mMap.get(key);
return v != null ? v : defValue;
}
}
public float getFloat(String key, float defValue) {
synchronized (this) {
awaitLoadedLocked();
Float v = (Float)mMap.get(key);
return v != null ? v : defValue;
}
}
public boolean getBoolean(String key, boolean defValue) {
synchronized (this) {
awaitLoadedLocked();
Boolean v = (Boolean)mMap.get(key);
return v != null ? v : defValue;
}
@@ -176,11 +244,23 @@ final class SharedPreferencesImpl implements SharedPreferences {
public boolean contains(String key) {
synchronized (this) {
awaitLoadedLocked();
return mMap.containsKey(key);
}
}
public Editor edit() {
// TODO: remove the need to call awaitLoadedLocked() when
// requesting an editor. will require some work on the
// Editor, but then we should be able to do:
//
// context.getSharedPreferences(..).edit().putString(..).apply()
//
// ... all without blocking.
synchronized (this) {
awaitLoadedLocked();
}
return new EditorImpl();
}