commit 63a2d51e0537eb4bd0653b842589dd4375883980
author Steven Moreland <smoreland@google.com> Fri Jun 25 01:10:15 2021 +0000
committer Steven Moreland <smoreland@google.com> Fri Jun 25 19:43:04 2021 +0000
tree 7b89a6a35b29b0fadac1cbee92aaf433c9aaed66
parent 28318606d85897024dcfd06107bfd87748f5c4bd

libbinder: attachObject APIs work with threads

These APIs now return values so that they can be used in a
multi-threaded environment without needing additional locking.

Bug: 192023359
Test: binderLibTest
Change-Id: Idc9054bde869a57c2cb5142963aae362674ce0c0

libs/binder/BpBinder.cpp

diff --git a/libs/binder/BpBinder.cpp b/libs/binder/BpBinder.cpp
index 5e44a0f..1f67825 100644
--- a/libs/binder/BpBinder.cpp
+++ b/libs/binder/BpBinder.cpp
@@ -61,22 +61,22 @@
     kill();
 }
 
-void BpBinder::ObjectManager::attach(
-    const void* objectID, void* object, void* cleanupCookie,
-    IBinder::object_cleanup_func func)
-{
+void* BpBinder::ObjectManager::attach(const void* objectID, void* object, void* cleanupCookie,
+                                      IBinder::object_cleanup_func func) {
     entry_t e;
     e.object = object;
     e.cleanupCookie = cleanupCookie;
     e.func = func;
 
-    if (mObjects.indexOfKey(objectID) >= 0) {
-        ALOGE("Trying to attach object ID %p to binder ObjectManager %p with object %p, but object ID already in use",
-                objectID, this,  object);
-        return;
+    if (ssize_t idx = mObjects.indexOfKey(objectID); idx >= 0) {
+        ALOGI("Trying to attach object ID %p to binder ObjectManager %p with object %p, but object "
+              "ID already in use",
+              objectID, this, object);
+        return mObjects[idx].object;
     }
 
     mObjects.add(objectID, e);
+    return nullptr;
 }
 
 void* BpBinder::ObjectManager::find(const void* objectID) const
@@ -86,9 +86,12 @@
     return mObjects.valueAt(i).object;
 }
 
-void BpBinder::ObjectManager::detach(const void* objectID)
-{
-    mObjects.removeItem(objectID);
+void* BpBinder::ObjectManager::detach(const void* objectID) {
+    ssize_t idx = mObjects.indexOfKey(objectID);
+    if (idx < 0) return nullptr;
+    void* value = mObjects[idx].object;
+    mObjects.removeItemsAt(idx, 1);
+    return value;
 }
 
 void BpBinder::ObjectManager::kill()
@@ -406,14 +409,11 @@
     recipient->binderDied(wp<BpBinder>::fromExisting(this));
 }
 
-
-void BpBinder::attachObject(
-    const void* objectID, void* object, void* cleanupCookie,
-    object_cleanup_func func)
-{
+void* BpBinder::attachObject(const void* objectID, void* object, void* cleanupCookie,
+                             object_cleanup_func func) {
     AutoMutex _l(mLock);
     ALOGV("Attaching object %p to binder %p (manager=%p)", object, this, &mObjects);
-    mObjects.attach(objectID, object, cleanupCookie, func);
+    return mObjects.attach(objectID, object, cleanupCookie, func);
 }
 
 void* BpBinder::findObject(const void* objectID) const
@@ -422,10 +422,9 @@
     return mObjects.find(objectID);
 }
 
-void BpBinder::detachObject(const void* objectID)
-{
+void* BpBinder::detachObject(const void* objectID) {
     AutoMutex _l(mLock);
-    mObjects.detach(objectID);
+    return mObjects.detach(objectID);
 }
 
 BpBinder* BpBinder::remoteBinder()