summaryrefslogtreecommitdiffstats
path: root/net/base/network_change_notifier.h
diff options
context:
space:
mode:
authorpkasting@chromium.org <pkasting@chromium.org@0039d316-1c4b-4281-b951-d872f2087c98>2010-06-25 21:30:38 +0000
committerpkasting@chromium.org <pkasting@chromium.org@0039d316-1c4b-4281-b951-d872f2087c98>2010-06-25 21:30:38 +0000
commit66761b95332549f825999e482c17c94675275f49 (patch)
treefc5307808a2c62f1eff2a9f37db3aff11c5455d9 /net/base/network_change_notifier.h
parente313f3b11360902a3da9b3b1cc0df2a4792d0867 (diff)
downloadchromium_src-66761b95332549f825999e482c17c94675275f49.zip
chromium_src-66761b95332549f825999e482c17c94675275f49.tar.gz
chromium_src-66761b95332549f825999e482c17c94675275f49.tar.bz2
Massively simplify the NetworkChangeNotifier infrastructure:
* Use a process-wide object (singleton pattern) * Create/destroy this object on the main thread, make it outlive all consumers * Make observer-related functions threadsafe As a result, the notifier can now be used by any thread (eliminating things like NetworkChangeObserverProxy and NetworkChangeNotifierProxy, and expanding its usefulness); its creation and inner workings are much simplified (eliminating implementation-specific classes); and it is simpler to access (eliminating things like NetworkChangeNotifierThread and a LOT of passing pointers around). BUG=none TEST=Unittests; network changes still trigger notifications Review URL: http://codereview.chromium.org/2802015 git-svn-id: svn://svn.chromium.org/chrome/trunk/src@50895 0039d316-1c4b-4281-b951-d872f2087c98
Diffstat (limited to 'net/base/network_change_notifier.h')
-rw-r--r--net/base/network_change_notifier.h63
1 files changed, 51 insertions, 12 deletions
diff --git a/net/base/network_change_notifier.h b/net/base/network_change_notifier.h
index 70b195d..e0a8800 100644
--- a/net/base/network_change_notifier.h
+++ b/net/base/network_change_notifier.h
@@ -6,11 +6,13 @@
#define NET_BASE_NETWORK_CHANGE_NOTIFIER_H_
#include "base/basictypes.h"
+#include "base/observer_list_threadsafe.h"
namespace net {
// NetworkChangeNotifier monitors the system for network changes, and notifies
-// observers on those events.
+// registered observers of those events. Observers may register on any thread,
+// and will be called back on the thread from which they registered.
class NetworkChangeNotifier {
public:
class Observer {
@@ -28,21 +30,58 @@ class NetworkChangeNotifier {
DISALLOW_COPY_AND_ASSIGN(Observer);
};
- NetworkChangeNotifier() {}
- virtual ~NetworkChangeNotifier() {}
+ virtual ~NetworkChangeNotifier();
- // These functions add and remove observers to/from the NetworkChangeNotifier.
- // Each call to AddObserver() must be matched with a corresponding call to
- // RemoveObserver() with the same parameter. Observers must remove themselves
- // before they get deleted, otherwise the NetworkChangeNotifier may try to
- // notify the wrong object.
- virtual void AddObserver(Observer* observer) = 0;
- virtual void RemoveObserver(Observer* observer) = 0;
+ // Creates the process-wide, platform-specific NetworkChangeNotifier. The
+ // caller owns the returned pointer. You may call this on any thread. You
+ // may also avoid creating this entirely (in which case nothing will be
+ // monitored), but if you do create it, you must do so before any other
+ // threads try to access the API below, and it must outlive all other threads
+ // which might try to use it.
+ static NetworkChangeNotifier* Create();
- // This will create the platform specific default NetworkChangeNotifier.
- static NetworkChangeNotifier* CreateDefaultNetworkChangeNotifier();
+#ifdef UNIT_TEST
+ // Like Create(), but for use in tests. The mock object doesn't monitor any
+ // events, it merely rebroadcasts notifications when requested.
+ static NetworkChangeNotifier* CreateMock() {
+ return new NetworkChangeNotifier();
+ }
+#endif
+
+ // Registers |observer| to receive notifications of network changes. The
+ // thread on which this is called is the thread on which |observer| will be
+ // called back with notifications. This is safe to call if Create() has not
+ // been called (as long as it doesn't race the Create() call on another
+ // thread), in which case it will simply do nothing.
+ static void AddObserver(Observer* observer);
+
+ // Unregisters |observer| from receiving notifications. This must be called
+ // on the same thread on which AddObserver() was called. Like AddObserver(),
+ // this is safe to call if Create() has not been called (as long as it doesn't
+ // race the Create() call on another thread), in which case it will simply do
+ // nothing. Technically, it's also safe to call after the notifier object has
+ // been destroyed, if the call doesn't race the notifier's destruction, but
+ // there's no reason to use the API in this risky way, so don't do it.
+ static void RemoveObserver(Observer* observer);
+
+#ifdef UNIT_TEST
+ // Allow unit tests to trigger notifications.
+ static void NotifyObserversOfIPAddressChangeForTests() {
+ NotifyObserversOfIPAddressChange();
+ }
+#endif
+
+ protected:
+ NetworkChangeNotifier();
+
+ // Broadcasts a notification to all registered observers. Note that this
+ // happens asynchronously, even for observers on the current thread, even in
+ // tests.
+ static void NotifyObserversOfIPAddressChange();
private:
+ const scoped_refptr<ObserverListThreadSafe<Observer> > observer_list_;
+
DISALLOW_COPY_AND_ASSIGN(NetworkChangeNotifier);
};