WifiScannerImpl.java revision ee0ab818341d44614ffe56ae73ecc08b974c2cbb 
1/*
2 * Copyright (C) 2015 The Android Open Source Project
3 *
4 * Licensed under the Apache License, Version 2.0 (the "License");
5 * you may not use this file except in compliance with the License.
6 * You may obtain a copy of the License at
7 *
8 *      http://www.apache.org/licenses/LICENSE-2.0
9 *
10 * Unless required by applicable law or agreed to in writing, software
11 * distributed under the License is distributed on an "AS IS" BASIS,
12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13 * See the License for the specific language governing permissions and
14 * limitations under the License.
15 */
16
17package com.android.server.wifi.scanner;
18
19import android.content.Context;
20import android.net.wifi.ScanResult;
21import android.net.wifi.WifiScanner;
22import android.os.Looper;
23
24import com.android.server.wifi.Clock;
25import com.android.server.wifi.WifiNative;
26
27import java.util.Comparator;
28
29/**
30 * Defines the interface to the Wifi hardware required for the WifiScanner API
31 */
32public abstract class WifiScannerImpl {
33
34    /**
35     * A factory that create a {@link com.android.server.wifi.scanner.WifiScannerImpl}
36     */
37    public static interface WifiScannerImplFactory {
38        WifiScannerImpl create(Context context, Looper looper, Clock clock);
39    }
40
41    /**
42     * Factory that create the implementation that is most appropriate for the system.
43     * This factory should only ever be used once.
44     */
45    public static final WifiScannerImplFactory DEFAULT_FACTORY = new WifiScannerImplFactory() {
46            public WifiScannerImpl create(Context context, Looper looper, Clock clock) {
47                WifiNative wifiNative = WifiNative.getWlanNativeInterface();
48                if (wifiNative.getScanCapabilities(new WifiNative.ScanCapabilities())) {
49                    return new HalWifiScannerImpl(context, wifiNative, looper, clock);
50                } else {
51                    return new SupplicantWifiScannerImpl(context, wifiNative, looper, clock);
52                }
53            }
54        };
55
56    /**
57     * A comparator that implements the sort order that is expected for scan results
58     */
59    protected static final Comparator<ScanResult> SCAN_RESULT_SORT_COMPARATOR =
60            new Comparator<ScanResult>() {
61        public int compare(ScanResult r1, ScanResult r2) {
62            return r2.level - r1.level;
63        }
64    };
65
66    /**
67     * Cleanup any ongoing operations. This may be called when the driver is unloaded.
68     * There is no expectation that failure events are returned for ongoing operations.
69     */
70    public abstract void cleanup();
71
72    /**
73     * Get the supported scan capabilities.
74     *
75     * @param capabilities Object that will be filled with the supported capabilities if successful
76     * @return true if the scan capabilities were retrieved successfully
77     */
78    public abstract boolean getScanCapabilities(WifiNative.ScanCapabilities capabilities);
79
80    /**
81     * Get a ChannelHelper that can be used to perform operations on scan channels
82     */
83    public abstract ChannelHelper getChannelHelper();
84
85    /**
86     * Start a one time scan. This method should only be called when there is no scan going on
87     * (after a callback indicating that the previous scan succeeded/failed).
88     * @return if the scan paramaters are valid
89     * Note this may return true even if the parameters are not accepted by the chip because the
90     * scan may be scheduled async.
91     */
92    public abstract boolean startSingleScan(WifiNative.ScanSettings settings,
93            WifiNative.ScanEventHandler eventHandler);
94    /**
95     * Get the scan results of the most recent single scan. This should be called immediately when
96     * the scan success callback is receieved.
97     */
98    public abstract WifiScanner.ScanData getLatestSingleScanResults();
99
100    /**
101     * Start a background scan. Calling this method while a background scan is already in process
102     * will interrupt the previous scan settings and replace it with the new ones.
103     * @return if the scan paramaters are valid
104     * Note this may return true even if the parameters are not accepted by the chip because the
105     * scan may be scheduled async.
106     */
107    public abstract boolean startBatchedScan(WifiNative.ScanSettings settings,
108            WifiNative.ScanEventHandler eventHandler);
109    /**
110     * Stop the currently active background scan
111     */
112    public abstract void stopBatchedScan();
113
114    /**
115     * Pause the currently active background scan
116     */
117    public abstract void pauseBatchedScan();
118
119    /**
120     * Restart the currently paused background scan
121     */
122    public abstract void restartBatchedScan();
123
124    /**
125     * Get the latest cached scan results from the last scan event. This should be called
126     * immediately when the scan success callback is receieved.
127     */
128    public abstract WifiScanner.ScanData[] getLatestBatchedScanResults(boolean flush);
129
130    /**
131     * Set PNO list to start PNO background scan.
132     * @param settings PNO settings for this scan.
133     * @param eventHandler Event handler for notifying the scan results.
134     * @return true if success, false otherwise
135     */
136    public abstract boolean setHwPnoList(WifiNative.PnoSettings settings,
137            WifiNative.PnoEventHandler eventHandler);
138
139    /**
140     * Reset PNO list to terminate PNO background scan.
141     * @return true if success, false otherwise
142     */
143    public abstract boolean resetHwPnoList();
144
145    /**
146     * This returns whether HW PNO is supported or not.
147     * @param isConnectedPno Whether this is connected PNO vs disconnected PNO.
148     * @return true if HW PNO is supported, false otherwise.
149     */
150    public abstract boolean isHwPnoSupported(boolean isConnectedPno);
151
152    /**
153     * This returns whether a background scan should be running for HW PNO scan or not.
154     * @return true if background scan needs to be started, false otherwise.
155     */
156    public abstract boolean shouldScheduleBackgroundScanForHwPno();
157
158    /**
159     * Set a new hotlist
160     */
161    public abstract boolean setHotlist(WifiScanner.HotlistSettings settings,
162            WifiNative.HotlistEventHandler eventHandler);
163
164    /**
165     * Reset any active hotlist
166     */
167    public abstract void resetHotlist();
168
169    /**
170     * Start tracking significant wifi changes
171     */
172    public abstract boolean trackSignificantWifiChange(WifiScanner.WifiChangeSettings settings,
173            WifiNative.SignificantWifiChangeEventHandler handler);
174
175    /**
176     * Stop tracking significant wifi changes
177     */
178    public abstract void untrackSignificantWifiChange();
179}
180