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Merge "Avoid unnecessary SharedPrefences disk writes." into gingerbread

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This commit is contained in:
Brad Fitzpatrick
2010-08-18 14:21:32 -07:00
committed by Android (Google) Code Review
parent aac6a74817 67fed01522
commit 11709ab07c
1 changed files with 28 additions and 6 deletions
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34
core/java/android/app/ContextImpl.java
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@@ -2844,6 +2844,7 @@ class ContextImpl extends Context {
boolean returnValue; boolean returnValue;
boolean hasListeners; boolean hasListeners;
boolean changesMade = false;
List<String> keysModified = null; List<String> keysModified = null;
Set<OnSharedPreferenceChangeListener> listeners = null; Set<OnSharedPreferenceChangeListener> listeners = null;
@@ -2857,17 +2858,31 @@ class ContextImpl extends Context {
synchronized (this) { synchronized (this) {
if (mClear) { if (mClear) {
mMap.clear(); if (!mMap.isEmpty()) {
changesMade = true;
mMap.clear();
}
mClear = false; mClear = false;
} }
for (Entry<String, Object> e : mModified.entrySet()) { for (Entry<String, Object> e : mModified.entrySet()) {
String k = e.getKey(); String k = e.getKey();
Object v = e.getValue(); Object v = e.getValue();
if (v == this) { if (v == this) { // magic value for a removal mutation
mMap.remove(k); if (mMap.containsKey(k)) {
mMap.remove(k);
changesMade = true;
}
} else { } else {
mMap.put(k, v); boolean isSame = false;
if (mMap.containsKey(k)) {
Object existingValue = mMap.get(k);
isSame = existingValue != null && existingValue.equals(v);
}
if (!isSame) {
mMap.put(k, v);
changesMade = true;
}
} }
if (hasListeners) { if (hasListeners) {
@@ -2878,7 +2893,7 @@ class ContextImpl extends Context {
mModified.clear(); mModified.clear();
} }
returnValue = writeFileLocked(); returnValue = writeFileLocked(changesMade);
} }
if (hasListeners) { if (hasListeners) {
@@ -2923,9 +2938,16 @@ class ContextImpl extends Context {
return str; return str;
} }
private boolean writeFileLocked() { private boolean writeFileLocked(boolean changesMade) {
// Rename the current file so it may be used as a backup during the next read // Rename the current file so it may be used as a backup during the next read
if (mFile.exists()) { if (mFile.exists()) {
if (!changesMade) {
// If the file already exists, but no changes were
// made to the underlying map, it's wasteful to
// re-write the file. Return as if we wrote it
// out.
return true;
}
if (!mBackupFile.exists()) { if (!mBackupFile.exists()) {
if (!mFile.renameTo(mBackupFile)) { if (!mFile.renameTo(mBackupFile)) {
Log.e(TAG, "Couldn't rename file " + mFile Log.e(TAG, "Couldn't rename file " + mFile