Add new Looper API to check whether the looper is idle.

This is just to support the watchdog to give it a faster
way to determine if a thread is deadlocked without having
to post a message to it.

Change-Id: I068dc8b9387caf94fe5811fb4aeb0f9b57b1a080

1 files changed, 12 insertions, 0 deletions

diff --git a/libs/utils/Looper.cpp b/libs/utils/Looper.cpp
index a5e6645..c51df2d 100644
--- a/libs/utils/Looper.cpp
+++ b/libs/utils/Looper.cpp
@@ -84,6 +84,8 @@ Looper::Looper(bool allowNonCallbacks) :
     LOG_ALWAYS_FATAL_IF(result != 0, "Could not make wake write pipe non-blocking.  errno=%d",
             errno);
 
+    mIdling = false;
+
     // Allocate the epoll instance and register the wake pipe.
     mEpollFd = epoll_create(EPOLL_SIZE_HINT);
     LOG_ALWAYS_FATAL_IF(mEpollFd < 0, "Could not create epoll instance.  errno=%d", errno);
@@ -214,9 +216,15 @@ int Looper::pollInner(int timeoutMillis) {
     mResponses.clear();
     mResponseIndex = 0;
 
+    // We are about to idle.
+    mIdling = true;
+
     struct epoll_event eventItems[EPOLL_MAX_EVENTS];
     int eventCount = epoll_wait(mEpollFd, eventItems, EPOLL_MAX_EVENTS, timeoutMillis);
 
+    // No longer idling.
+    mIdling = false;
+
     // Acquire lock.
     mLock.lock();
 
@@ -558,4 +566,8 @@ void Looper::removeMessages(const sp<MessageHandler>& handler, int what) {
     } // release lock
 }
 
+bool Looper::isIdling() const {
+    return mIdling;
+}
+
 } // namespace android