Android/frameworks_base
1
0
Fork 0
Code Issues Pull Requests Actions Packages Projects Releases Wiki Activity

Fix MulticastLock API to match WifiLock API.

Browse Source 
Adds option to make lock refcounted or not.  Fixes 2017680.
This commit is contained in:
Robert Greenwalt
2009-07-29 16:18:38 -07:00
parent 0067057c31
commit 41c1043399
2 changed files with 79 additions and 12 deletions
Download Patch File Download Diff File Expand all files Collapse all files

13
api/current.xml
View File

@@ -79956,6 +79956,19 @@
visibility="public"
>
</method>
<method name="setReferenceCounted"
return="void"
abstract="false"
native="false"
synchronized="false"
static="false"
final="false"
deprecated="not deprecated"
visibility="public"
>
<parameter name="refCounted" type="boolean">
</parameter>
</method>
</class>
<class name="WifiManager.WifiLock"
extends="java.lang.Object"

78
wifi/java/android/net/wifi/WifiManager.java
View File

@@ -870,7 +870,10 @@ public class WifiManager {
* Create a new MulticastLock
*
* @param tag a tag for the MulticastLock to identify it in debugging
* messages.
* messages. This string is never shown to the user under
* normal conditions, but should be descriptive enough to
* identify your application and the specific MulticastLock
* within it, if it holds multiple MulticastLocks.
*
* @return a new, unacquired MulticastLock with the given tag.
*
@@ -886,26 +889,36 @@ public class WifiManager {
* addressed to this device. Acquring a MulticastLock will
* cause the stack to receive packets addressed to multicast
* addresses. Processing these extra packets can cause a noticable
* battery drain and should be disabled when not needed
* battery drain and should be disabled when not needed.
*/
public class MulticastLock {
private String mTag;
private final IBinder mBinder;
private int mRefCount;
private boolean mRefCounted;
private boolean mHeld;
private MulticastLock(String tag) {
mTag = tag;
mBinder = new Binder();
mRefCount = 0;
mRefCounted = true;
mHeld = false;
}
/**
* Locks Wifi Multicast on until {@link #release} is called.
*
* The first call to {@code acquire} will lock the Multicast on
* but subsequent calls will be ignored. Only one call to
* {@link #release} will be required, regardless of the number of
* times that {@code acquire} is called.
* If this MulticastLock is reference-counted each call to
* {@code acquire} will increment the reference count, and the
* wifi interface will receive multicast packets as long as the
* reference count is above zero.
*
* If this MulticastLock is not reference-counted, the first call to
* {@code acquire} will turn on the multicast packets, but subsequent
* calls will be ignored. Only one call to {@link #release} will
* be required, regardless of the number of times that {@code acquire}
* is called.
*
* Note that other applications may also lock Wifi Multicast on.
* Only they can relinquish their lock.
@@ -915,7 +928,7 @@ public class WifiManager {
*/
public void acquire() {
synchronized (mBinder) {
if (!mHeld) {
if (mRefCounted ? (++mRefCount > 0) : (!mHeld)) {
try {
mService.acquireMulticastLock(mBinder, mTag);
synchronized (WifiManager.this) {
@@ -926,9 +939,9 @@ public class WifiManager {
}
mActiveLockCount++;
}
mHeld = true;
} catch (RemoteException ignore) {
}
mHeld = true;
}
}
}
@@ -937,6 +950,18 @@ public class WifiManager {
* Unlocks Wifi Multicast, restoring the filter of packets
* not addressed specifically to this device and saving power.
*
* If this MulticastLock is reference-counted, each call to
* {@code release} will decrement the reference count, and the
* multicast packets will only stop being received when the reference
* count reaches zero. If the reference count goes below zero (that
* is, if {@code release} is called a greater number of times than
* {@link #acquire}), an exception is thrown.
*
* If this MulticastLock is not reference-counted, the first call to
* {@code release} (after the radio was multicast locked using
* {@linke #acquire}) will unlock the multicast, and subsequent calls
* will be ignored.
*
* Note that if any other Wifi Multicast Locks are still outstanding
* this {@code release} call will not have an immediate effect. Only
* when all applications have released all their Multicast Locks will
@@ -947,19 +972,42 @@ public class WifiManager {
*/
public void release() {
synchronized (mBinder) {
if (mHeld) {
if (mRefCounted ? (--mRefCount == 0) : (mHeld)) {
try {
mService.releaseMulticastLock();
synchronized (WifiManager.this) {
mActiveLockCount--;
}
mHeld = false;
} catch (RemoteException ignore) {
}
mHeld = false;
}
if (mRefCount < 0) {
throw new RuntimeException("MulticastLock under-locked "
+ mTag);
}
}
}
/**
* Controls whether this is a reference-counted or non-reference-
* counted MulticastLock.
*
* Reference-counted MulticastLocks keep track of the number of calls
* to {@link #acquire} and {@link #release}, and only stop the
* reception of multicast packets when every call to {@link #acquire}
* has been balanced with a call to {@link #release}. Non-reference-
* counted MulticastLocks allow the reception of multicast packets
* whenever {@link #acquire} is called and stop accepting multicast
* packets whenever {@link #release} is called.
*
* @param refCounted true if this MulticastLock should keep a reference
* count
*/
public void setReferenceCounted(boolean refCounted) {
mRefCounted = refCounted;
}
/**
* Checks whether this MulticastLock is currently held.
*
@@ -972,17 +1020,23 @@ public class WifiManager {
}
public String toString() {
String s1, s2;
String s1, s2, s3;
synchronized (mBinder) {
s1 = Integer.toHexString(System.identityHashCode(this));
s2 = mHeld ? "held; " : "";
return "MulticastLock{ " + s1 + "; " + s2 + " }";
if (mRefCounted) {
s3 = "refcounted: refcount = " + mRefCount;
} else {
s3 = "not refcounted";
}
return "MulticastLock{ " + s1 + "; " + s2 + s3 + " }";
}
}
@Override
protected void finalize() throws Throwable {
super.finalize();
setReferenceCounted(false);
release();
}
}