core/java/android/os/StatFs.java

/*
 * Copyright (C) 2007 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.os;

/**
 * Retrieve overall information about the space on a filesystem.  This is a
 * Wrapper for Unix statfs().
 */
public class StatFs {
    /**
     * Construct a new StatFs for looking at the stats of the
     * filesystem at <var>path</var>.  Upon construction, the stat of
     * the file system will be performed, and the values retrieved available
     * from the methods on this class.
     * 
     * @param path A path in the desired file system to state.
     */
    public StatFs(String path) { native_setup(path); }
    
    /**
     * Perform a restat of the file system referenced by this object.  This
     * is the same as re-constructing the object with the same file system
     * path, and the new stat values are available upon return.
     */
    public void restat(String path) { native_restat(path); }

    @Override
    protected void finalize() { native_finalize(); }

    /**
     * The size, in bytes, of a block on the file system.  This corresponds
     * to the Unix statfs.f_bsize field.
     */
    public native int getBlockSize();

    /**
     * The total number of blocks on the file system.  This corresponds
     * to the Unix statfs.f_blocks field.
     */
    public native int getBlockCount();

    /**
     * The total number of blocks that are free on the file system, including
     * reserved blocks (that are not available to normal applications).  This
     * corresponds to the Unix statfs.f_bfree field.  Most applications will
     * want to use {@link #getAvailableBlocks()} instead.
     */
    public native int getFreeBlocks();

    /**
     * The number of blocks that are free on the file system and available to
     * applications.  This corresponds to the Unix statfs.f_bavail field.
     */
    public native int getAvailableBlocks();    
    
    private int mNativeContext;
    private native void native_restat(String path);
    private native void native_setup(String path);
    private native void native_finalize();
}