libbinder_ndk: compiles w/o weak symbols

Android platform builds with weak symbols, but apps don't.

getDescriptor - ifdefed
AParcelableHolder - simplified - this was added in API level 31
  so lifting checks to be about the whole class

Bug: 257135519
Bug: 219987524
Test: build w/ `-U__ANDROID_UNAVAILABLE_SYMBOLS_ARE_WEAK__`
Test: atest CtsNdkBinderTestCases
Test: atest CtsNdkBinderTestCases (w/ -U__ANDROID_UNAVAILABLE_SYMBOLS_ARE_WEAK__)
Change-Id: I8e0b03b775609b1c987da42a54ed070a64eda201
diff --git a/libs/binder/ndk/include_cpp/android/binder_auto_utils.h b/libs/binder/ndk/include_cpp/android/binder_auto_utils.h
index fccc0af..d24c978 100644
--- a/libs/binder/ndk/include_cpp/android/binder_auto_utils.h
+++ b/libs/binder/ndk/include_cpp/android/binder_auto_utils.h
@@ -270,14 +270,19 @@
     std::string getDescription() const {
 #ifdef __ANDROID_UNAVAILABLE_SYMBOLS_ARE_WEAK__
         if (__builtin_available(android 30, *)) {
-#else
-        if (__ANDROID_API__ >= 30) {
 #endif
+
+#if defined(__ANDROID_UNAVAILABLE_SYMBOLS_ARE_WEAK__) || __ANDROID_API__ >= 30
             const char* cStr = AStatus_getDescription(get());
             std::string ret = cStr;
             AStatus_deleteDescription(cStr);
             return ret;
+#endif
+
+#ifdef __ANDROID_UNAVAILABLE_SYMBOLS_ARE_WEAK__
         }
+#endif
+
         binder_exception_t exception = getExceptionCode();
         std::string desc = std::to_string(exception);
         if (exception == EX_SERVICE_SPECIFIC) {
diff --git a/libs/binder/ndk/include_cpp/android/binder_parcelable_utils.h b/libs/binder/ndk/include_cpp/android/binder_parcelable_utils.h
index c1f2620..caee471 100644
--- a/libs/binder/ndk/include_cpp/android/binder_parcelable_utils.h
+++ b/libs/binder/ndk/include_cpp/android/binder_parcelable_utils.h
@@ -41,68 +41,34 @@
         if (_status != STATUS_OK) return _status; \
     } while (false)
 
+// AParcelableHolder has been introduced in 31.
+#if __ANDROID_API__ >= 31
 class AParcelableHolder {
    public:
     AParcelableHolder() = delete;
     explicit AParcelableHolder(parcelable_stability_t stability)
         : mParcel(AParcel_create()), mStability(stability) {}
 
-#if __ANDROID_API__ >= 31
     AParcelableHolder(const AParcelableHolder& other)
         : mParcel(AParcel_create()), mStability(other.mStability) {
-        // AParcelableHolder has been introduced in 31.
-#ifdef __ANDROID_UNAVAILABLE_SYMBOLS_ARE_WEAK__
-        if (__builtin_available(android 31, *)) {
-#else
-        if (__ANDROID_API__ >= 31) {
-#endif
-            AParcel_appendFrom(other.mParcel.get(), this->mParcel.get(), 0,
-                               AParcel_getDataSize(other.mParcel.get()));
-        } else {
-            syslog(LOG_ERR,
-                   "sdk_version not compatible, AParcelableHolder need sdk_version >= 31!");
-        }
+        AParcel_appendFrom(other.mParcel.get(), this->mParcel.get(), 0,
+                           AParcel_getDataSize(other.mParcel.get()));
     }
-#endif
 
     AParcelableHolder(AParcelableHolder&& other) = default;
     virtual ~AParcelableHolder() = default;
 
     binder_status_t writeToParcel(AParcel* parcel) const {
         RETURN_ON_FAILURE(AParcel_writeInt32(parcel, static_cast<int32_t>(this->mStability)));
-#ifdef __ANDROID_UNAVAILABLE_SYMBOLS_ARE_WEAK__
-        if (__builtin_available(android 31, *)) {
-#else
-        if (__ANDROID_API__ >= 31) {
-#endif
-            int32_t size = AParcel_getDataSize(this->mParcel.get());
-            RETURN_ON_FAILURE(AParcel_writeInt32(parcel, size));
-        } else {
-            return STATUS_INVALID_OPERATION;
-        }
-#ifdef __ANDROID_UNAVAILABLE_SYMBOLS_ARE_WEAK__
-        if (__builtin_available(android 31, *)) {
-#else
-        if (__ANDROID_API__ >= 31) {
-#endif
-            int32_t size = AParcel_getDataSize(this->mParcel.get());
-            RETURN_ON_FAILURE(AParcel_appendFrom(this->mParcel.get(), parcel, 0, size));
-        } else {
-            return STATUS_INVALID_OPERATION;
-        }
+        int32_t size = AParcel_getDataSize(this->mParcel.get());
+        RETURN_ON_FAILURE(AParcel_writeInt32(parcel, size));
+        size = AParcel_getDataSize(this->mParcel.get());
+        RETURN_ON_FAILURE(AParcel_appendFrom(this->mParcel.get(), parcel, 0, size));
         return STATUS_OK;
     }
 
     binder_status_t readFromParcel(const AParcel* parcel) {
-#ifdef __ANDROID_UNAVAILABLE_SYMBOLS_ARE_WEAK__
-        if (__builtin_available(android 31, *)) {
-#else
-        if (__ANDROID_API__ >= 31) {
-#endif
-            AParcel_reset(mParcel.get());
-        } else {
-            return STATUS_INVALID_OPERATION;
-        }
+        AParcel_reset(mParcel.get());
 
         parcelable_stability_t wireStability;
         RETURN_ON_FAILURE(AParcel_readInt32(parcel, &wireStability));
@@ -123,15 +89,7 @@
             return STATUS_BAD_VALUE;
         }
 
-#ifdef __ANDROID_UNAVAILABLE_SYMBOLS_ARE_WEAK__
-        if (__builtin_available(android 31, *)) {
-#else
-        if (__ANDROID_API__ >= 31) {
-#endif
-            status = AParcel_appendFrom(parcel, mParcel.get(), dataStartPos, dataSize);
-        } else {
-            status = STATUS_INVALID_OPERATION;
-        }
+        status = AParcel_appendFrom(parcel, mParcel.get(), dataStartPos, dataSize);
         if (status != STATUS_OK) {
             return status;
         }
@@ -143,15 +101,7 @@
         if (this->mStability > T::_aidl_stability) {
             return STATUS_BAD_VALUE;
         }
-#ifdef __ANDROID_UNAVAILABLE_SYMBOLS_ARE_WEAK__
-        if (__builtin_available(android 31, *)) {
-#else
-        if (__ANDROID_API__ >= 31) {
-#endif
-            AParcel_reset(mParcel.get());
-        } else {
-            return STATUS_INVALID_OPERATION;
-        }
+        AParcel_reset(mParcel.get());
         AParcel_writeString(mParcel.get(), T::descriptor, strlen(T::descriptor));
         p.writeToParcel(mParcel.get());
         return STATUS_OK;
@@ -161,17 +111,9 @@
     binder_status_t getParcelable(std::optional<T>* ret) const {
         const std::string parcelableDesc(T::descriptor);
         AParcel_setDataPosition(mParcel.get(), 0);
-#ifdef __ANDROID_UNAVAILABLE_SYMBOLS_ARE_WEAK__
-        if (__builtin_available(android 31, *)) {
-#else
-        if (__ANDROID_API__ >= 31) {
-#endif
-            if (AParcel_getDataSize(mParcel.get()) == 0) {
-                *ret = std::nullopt;
-                return STATUS_OK;
-            }
-        } else {
-            return STATUS_INVALID_OPERATION;
+        if (AParcel_getDataSize(mParcel.get()) == 0) {
+            *ret = std::nullopt;
+            return STATUS_OK;
         }
         std::string parcelableDescInParcel;
         binder_status_t status = AParcel_readString(mParcel.get(), &parcelableDescInParcel);
@@ -188,18 +130,7 @@
         return STATUS_OK;
     }
 
-    void reset() {
-#ifdef __ANDROID_UNAVAILABLE_SYMBOLS_ARE_WEAK__
-        if (__builtin_available(android 31, *)) {
-#else
-        if (__ANDROID_API__ >= 31) {
-#endif
-            AParcel_reset(mParcel.get());
-        } else {
-            syslog(LOG_ERR,
-                   "sdk_version not compatible, AParcelableHolder need sdk_version >= 31!");
-        }
-    }
+    void reset() { AParcel_reset(mParcel.get()); }
 
     inline bool operator!=(const AParcelableHolder& rhs) const { return this != &rhs; }
     inline bool operator<(const AParcelableHolder& rhs) const { return this < &rhs; }
@@ -207,34 +138,23 @@
     inline bool operator==(const AParcelableHolder& rhs) const { return this == &rhs; }
     inline bool operator>(const AParcelableHolder& rhs) const { return this > &rhs; }
     inline bool operator>=(const AParcelableHolder& rhs) const { return this >= &rhs; }
-#if __ANDROID_API__ >= 31
     inline AParcelableHolder& operator=(const AParcelableHolder& rhs) {
-        // AParcelableHolder has been introduced in 31.
-#ifdef __ANDROID_UNAVAILABLE_SYMBOLS_ARE_WEAK__
-        if (__builtin_available(android 31, *)) {
-#else
-        if (__ANDROID_API__ >= 31) {
-#endif
-            this->reset();
-            if (this->mStability != rhs.mStability) {
-                syslog(LOG_ERR, "AParcelableHolder stability mismatch: this %d rhs %d!",
-                       this->mStability, rhs.mStability);
-                abort();
-            }
-            AParcel_appendFrom(rhs.mParcel.get(), this->mParcel.get(), 0,
-                               AParcel_getDataSize(rhs.mParcel.get()));
-        } else {
-            syslog(LOG_ERR,
-                   "sdk_version not compatible, AParcelableHolder need sdk_version >= 31!");
+        this->reset();
+        if (this->mStability != rhs.mStability) {
+            syslog(LOG_ERR, "AParcelableHolder stability mismatch: this %d rhs %d!",
+                   this->mStability, rhs.mStability);
+            abort();
         }
+        AParcel_appendFrom(rhs.mParcel.get(), this->mParcel.get(), 0,
+                           AParcel_getDataSize(rhs.mParcel.get()));
         return *this;
     }
-#endif
 
    private:
     mutable ndk::ScopedAParcel mParcel;
     parcelable_stability_t mStability;
 };
+#endif  // __ANDROID_API__ >= 31
 
 #undef RETURN_ON_FAILURE
 }  // namespace ndk
diff --git a/libs/binder/ndk/include_cpp/android/binder_to_string.h b/libs/binder/ndk/include_cpp/android/binder_to_string.h
index d7840ec..6a25db2 100644
--- a/libs/binder/ndk/include_cpp/android/binder_to_string.h
+++ b/libs/binder/ndk/include_cpp/android/binder_to_string.h
@@ -136,8 +136,10 @@
     template <typename _U>
     static std::enable_if_t<
 #ifdef HAS_NDK_INTERFACE
-            std::is_base_of_v<::ndk::ICInterface, _U> ||
-                    std::is_same_v<::ndk::AParcelableHolder, _U>
+            std::is_base_of_v<::ndk::ICInterface, _U>
+#if __ANDROID_API__ >= 31
+                    || std::is_same_v<::ndk::AParcelableHolder, _U>
+#endif
 #else
             std::is_base_of_v<IInterface, _U> || std::is_same_v<IBinder, _U> ||
                     std::is_same_v<os::ParcelFileDescriptor, _U> ||