Change argument of active services callback to bool.

Instead of passing the number of active services, pass a bool
that represents if there are clients.

Bug: 176239128
Test: test aidl_lazy_test

Change-Id: I8180547dfe4ebc11d5d7bb3a7306bc79f839d715
Merged-In: I8180547dfe4ebc11d5d7bb3a7306bc79f839d715
(cherry-picked from 1afb14e050360ece9f127bf27bb416cb274f0eed)

2 files changed, 28 insertions, 24 deletions

diff --git a/libs/binder/LazyServiceRegistrar.cpp b/libs/binder/LazyServiceRegistrar.cpp
index bfd6942c3e..68ea8a6d79 100644
--- a/libs/binder/LazyServiceRegistrar.cpp
+++ b/libs/binder/LazyServiceRegistrar.cpp
@@ -38,8 +38,7 @@ public:
                          bool allowIsolated, int dumpFlags);
     void forcePersist(bool persist);
 
-    void setActiveServicesCountCallback(const std::function<bool(int)>&
-                                        activeServicesCountCallback);
+    void setActiveServicesCallback(const std::function<bool(bool)>& activeServicesCallback);
 
     bool tryUnregister();
 
@@ -68,6 +67,9 @@ private:
      */
     size_t mNumConnectedServices;
 
+    // previous value passed to the active services callback
+    std::optional<bool> mPreviousHasClients;
+
     struct Service {
         sp<IBinder> service;
         bool allowIsolated;
@@ -82,8 +84,8 @@ private:
 
     bool mForcePersist;
 
-    // Callback used to report the number of services with clients
-    std::function<bool(int)> mActiveServicesCountCallback;
+    // Callback used to report if there are services with clients
+    std::function<bool(bool)> mActiveServicesCallback;
 };
 
 class ClientCounterCallback {
@@ -98,8 +100,7 @@ public:
      */
     void forcePersist(bool persist);
 
-    void setActiveServicesCountCallback(const std::function<bool(int)>&
-                                        activeServicesCountCallback);
+    void setActiveServicesCallback(const std::function<bool(bool)>& activeServicesCallback);
 
     bool tryUnregister();
 
@@ -137,7 +138,7 @@ bool ClientCounterCallbackImpl::registerService(const sp<IBinder>& service, cons
 
 void ClientCounterCallbackImpl::forcePersist(bool persist) {
     mForcePersist = persist;
-    if (!mForcePersist && mNumConnectedServices == 0) {
+    if (!mForcePersist) {
         // Attempt a shutdown in case the number of clients hit 0 while the flag was on
         maybeTryShutdown();
     }
@@ -183,8 +184,12 @@ void ClientCounterCallbackImpl::maybeTryShutdown() {
     }
 
     bool handledInCallback = false;
-    if (mActiveServicesCountCallback != nullptr) {
-        handledInCallback = mActiveServicesCountCallback(mNumConnectedServices);
+    if (mActiveServicesCallback != nullptr) {
+        bool hasClients = mNumConnectedServices != 0;
+        if (hasClients != mPreviousHasClients) {
+            handledInCallback = mActiveServicesCallback(hasClients);
+            mPreviousHasClients = hasClients;
+        }
     }
 
     // If there is no callback defined or the callback did not handle this
@@ -225,9 +230,9 @@ Status ClientCounterCallbackImpl::onClients(const sp<IBinder>& service, bool cli
     reRegister();
 }
 
-void ClientCounterCallbackImpl::setActiveServicesCountCallback(const std::function<bool(int)>&
-                                                               activeServicesCountCallback) {
-    mActiveServicesCountCallback = activeServicesCountCallback;
+void ClientCounterCallbackImpl::setActiveServicesCallback(const std::function<bool(bool)>&
+                                                          activeServicesCallback) {
+    mActiveServicesCallback = activeServicesCallback;
 }
 
 ClientCounterCallback::ClientCounterCallback() {
@@ -243,9 +248,9 @@ void ClientCounterCallback::forcePersist(bool persist) {
     mImpl->forcePersist(persist);
 }
 
-void ClientCounterCallback::setActiveServicesCountCallback(const std::function<bool(int)>&
-                                                           activeServicesCountCallback) {
-    mImpl->setActiveServicesCountCallback(activeServicesCountCallback);
+void ClientCounterCallback::setActiveServicesCallback(const std::function<bool(bool)>&
+                                                      activeServicesCallback) {
+    mImpl->setActiveServicesCallback(activeServicesCallback);
 }
 
 bool ClientCounterCallback::tryUnregister() {
@@ -279,9 +284,9 @@ void LazyServiceRegistrar::forcePersist(bool persist) {
     mClientCC->forcePersist(persist);
 }
 
-void LazyServiceRegistrar::setActiveServicesCountCallback(const std::function<bool(int)>&
-                                                          activeServicesCountCallback) {
-    mClientCC->setActiveServicesCountCallback(activeServicesCountCallback);
+void LazyServiceRegistrar::setActiveServicesCallback(const std::function<bool(bool)>&
+                                                     activeServicesCallback) {
+    mClientCC->setActiveServicesCallback(activeServicesCallback);
 }
 
 bool LazyServiceRegistrar::tryUnregister() {
diff --git a/libs/binder/include/binder/LazyServiceRegistrar.h b/libs/binder/include/binder/LazyServiceRegistrar.h
index 73893c7dd0..96597320f6 100644
--- a/libs/binder/include/binder/LazyServiceRegistrar.h
+++ b/libs/binder/include/binder/LazyServiceRegistrar.h
@@ -56,10 +56,10 @@ class LazyServiceRegistrar {
      void forcePersist(bool persist);
 
      /**
-      * Set a callback that is executed when the total number of services with
-      * clients changes.
-      * The callback takes an argument, which is the number of registered
-      * lazy services for this process which have clients.
+      * Set a callback that is invoked when the active service count (i.e. services with clients)
+      * registered with this process drops to zero (or becomes nonzero).
+      * The callback takes a boolean argument, which is 'true' if there is
+      * at least one service with clients.
       *
       * Callback return value:
       * - false: Default behavior for lazy services (shut down the process if there
@@ -73,8 +73,7 @@ class LazyServiceRegistrar {
       *
       * This method should be called before 'registerService' to avoid races.
       */
-     void setActiveServicesCountCallback(const std::function<bool(int)>&
-                                         activeServicesCountCallback);
+     void setActiveServicesCallback(const std::function<bool(bool)>& activeServicesCallback);
 
     /**
       * Try to unregister all services previously registered with 'registerService'.