Merge "Avoid unnecessary SharedPrefences disk writes." into gingerbread (11709ab0) · Commits · e / os / android_frameworks_base

core/java/android/app/ContextImpl.java

+28 −6

Original line number	Diff line number	Diff line
		@@ -2844,6 +2844,7 @@ class ContextImpl extends Context {
		boolean returnValue;

		boolean hasListeners;
		boolean changesMade = false;
		List<String> keysModified = null;
		Set<OnSharedPreferenceChangeListener> listeners = null;

		@@ -2857,17 +2858,31 @@ class ContextImpl extends Context {

		synchronized (this) {
		if (mClear) {
		if (!mMap.isEmpty()) {
		changesMade = true;
		mMap.clear();
		}
		mClear = false;
		}

		for (Entry<String, Object> e : mModified.entrySet()) {
		String k = e.getKey();
		Object v = e.getValue();
		if (v == this) {
		if (v == this) { // magic value for a removal mutation
		if (mMap.containsKey(k)) {
		mMap.remove(k);
		changesMade = true;
		}
		} else {
		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) {
		@@ -2878,7 +2893,7 @@ class ContextImpl extends Context {
		mModified.clear();
		}

		returnValue = writeFileLocked();
		returnValue = writeFileLocked(changesMade);
		}

		if (hasListeners) {
		@@ -2923,9 +2938,16 @@ class ContextImpl extends Context {
		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
		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 (!mFile.renameTo(mBackupFile)) {
		Log.e(TAG, "Couldn't rename file " + mFile