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/*
* Copyright (C) 2011 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 android.database.sqlite;
import android.content.res.Resources;
import android.os.StatFs;
import android.os.SystemProperties;
/**
* Provides access to SQLite functions that affect all database connection,
* such as memory management.
*
* The native code associated with SQLiteGlobal is also sets global configuration options
* using sqlite3_config() then calls sqlite3_initialize() to ensure that the SQLite
* library is properly initialized exactly once before any other framework or application
* code has a chance to run.
*
* Verbose SQLite logging is enabled if the "log.tag.SQLiteLog" property is set to "V".
* (per {@link SQLiteDebug#DEBUG_SQL_LOG}).
*
* @hide
*/
public final class SQLiteGlobal {
private static final String TAG = "SQLiteGlobal";
private static final Object sLock = new Object();
private static int sDefaultPageSize;
private static native int nativeReleaseMemory();
private SQLiteGlobal() {
}
/**
* Attempts to release memory by pruning the SQLite page cache and other
* internal data structures.
*
* @return The number of bytes that were freed.
*/
public static int releaseMemory() {
return nativeReleaseMemory();
}
/**
* Gets the default page size to use when creating a database.
*/
public static int getDefaultPageSize() {
synchronized (sLock) {
if (sDefaultPageSize == 0) {
sDefaultPageSize = new StatFs("/data").getBlockSize();
}
return SystemProperties.getInt("debug.sqlite.pagesize", sDefaultPageSize);
}
}
/**
* Gets the default journal mode when WAL is not in use.
*/
public static String getDefaultJournalMode() {
return SystemProperties.get("debug.sqlite.journalmode",
Resources.getSystem().getString(
com.android.internal.R.string.db_default_journal_mode));
}
/**
* Gets the journal size limit in bytes.
*/
public static int getJournalSizeLimit() {
return SystemProperties.getInt("debug.sqlite.journalsizelimit",
Resources.getSystem().getInteger(
com.android.internal.R.integer.db_journal_size_limit));
}
/**
* Gets the default database synchronization mode when WAL is not in use.
*/
public static String getDefaultSyncMode() {
return SystemProperties.get("debug.sqlite.syncmode",
Resources.getSystem().getString(
com.android.internal.R.string.db_default_sync_mode));
}
/**
* Gets the database synchronization mode when in WAL mode.
*/
public static String getWALSyncMode() {
return SystemProperties.get("debug.sqlite.wal.syncmode",
Resources.getSystem().getString(
com.android.internal.R.string.db_wal_sync_mode));
}
/**
* Gets the WAL auto-checkpoint integer in database pages.
*/
public static int getWALAutoCheckpoint() {
int value = SystemProperties.getInt("debug.sqlite.wal.autocheckpoint",
Resources.getSystem().getInteger(
com.android.internal.R.integer.db_wal_autocheckpoint));
return Math.max(1, value);
}
/**
* Gets the connection pool size when in WAL mode.
*/
public static int getWALConnectionPoolSize() {
int value = SystemProperties.getInt("debug.sqlite.wal.poolsize",
Resources.getSystem().getInteger(
com.android.internal.R.integer.db_connection_pool_size));
return Math.max(2, value);
}
}
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