libbinder_ndk: remove associateClassInternal
The code here was pretty difficult to understand.
Bug: 262463798
Test: atest CtsNdkBinderTestCases
Change-Id: Ie9920192a685149d3d5723e83246d59aa8ef50f4
diff --git a/libs/binder/ndk/ibinder.cpp b/libs/binder/ndk/ibinder.cpp
index 28d1f16..b29f22e 100644
--- a/libs/binder/ndk/ibinder.cpp
+++ b/libs/binder/ndk/ibinder.cpp
@@ -75,8 +75,29 @@
AIBinder::AIBinder(const AIBinder_Class* clazz) : mClazz(clazz) {}
AIBinder::~AIBinder() {}
-std::optional<bool> AIBinder::associateClassInternal(const AIBinder_Class* clazz,
- const String16& newDescriptor, bool set) {
+// b/175635923 libcxx causes "implicit-conversion" with a string with invalid char
+static std::string SanitizeString(const String16& str) {
+ std::string sanitized{String8(str)};
+ for (auto& c : sanitized) {
+ if (!isprint(c)) {
+ c = '?';
+ }
+ }
+ return sanitized;
+}
+
+bool AIBinder::associateClass(const AIBinder_Class* clazz) {
+ if (clazz == nullptr) return false;
+
+ // If mClazz is non-null, this must have been called and cached
+ // already. So, we can safely call this first. Due to the implementation
+ // of getInterfaceDescriptor (at time of writing), two simultaneous calls
+ // may lead to extra binder transactions, but this is expected to be
+ // exceedingly rare. Once we have a binder, when we get it again later,
+ // we won't make another binder transaction here.
+ const String16& descriptor = getBinder()->getInterfaceDescriptor();
+ const String16& newDescriptor = clazz->getInterfaceDescriptor();
+
std::lock_guard<std::mutex> lock(mClazzMutex);
if (mClazz == clazz) return true;
@@ -94,40 +115,14 @@
}
// always a failure because we know mClazz != clazz
+ // TODO(b/262463798): support multiple ABpBinder in different namespaces
return false;
}
- if (set) {
- // if this is a local object, it's not one known to libbinder_ndk
- mClazz = clazz;
- return true;
- }
-
- return {};
-}
-
-// b/175635923 libcxx causes "implicit-conversion" with a string with invalid char
-static std::string SanitizeString(const String16& str) {
- std::string sanitized{String8(str)};
- for (auto& c : sanitized) {
- if (!isprint(c)) {
- c = '?';
- }
- }
- return sanitized;
-}
-
-bool AIBinder::associateClass(const AIBinder_Class* clazz) {
- if (clazz == nullptr) return false;
-
- const String16& newDescriptor = clazz->getInterfaceDescriptor();
-
- auto result = associateClassInternal(clazz, newDescriptor, false);
- if (result.has_value()) return *result;
-
- CHECK(asABpBinder() != nullptr); // ABBinder always has a descriptor
-
- const String16& descriptor = getBinder()->getInterfaceDescriptor();
+ // This will always be an O(n) comparison, but it's expected to be extremely rare.
+ // since it's an error condition. Do the comparison after we take the lock and
+ // check the pointer equality fast path. By always taking the lock, it's also
+ // more flake-proof. However, the check is not dependent on the lock.
if (descriptor != newDescriptor) {
if (getBinder()->isBinderAlive()) {
LOG(ERROR) << __func__ << ": Expecting binder to have class '" << newDescriptor
@@ -141,7 +136,9 @@
return false;
}
- return associateClassInternal(clazz, newDescriptor, true).value();
+ // if this is a local object, it's not one known to libbinder_ndk
+ mClazz = clazz;
+ return true;
}
ABBinder::ABBinder(const AIBinder_Class* clazz, void* userData)