Move security credentials, connectors, and auth context to C++

This is to use `grpc_core::RefCount` to improve performnace.
This commit also replaces explicit C vtables, with C++ vtable
with its own compile time assertions and performance benefits.
It also makes use of `RefCountedPtr` wherever possible.

2 files changed, 10 insertions, 5 deletions

diff --git a/src/cpp/client/secure_credentials.cc b/src/cpp/client/secure_credentials.cc
index d0abe441a6..4d0ed355ab 100644
--- a/src/cpp/client/secure_credentials.cc
+++ b/src/cpp/client/secure_credentials.cc
@@ -261,10 +261,10 @@ void MetadataCredentialsPluginWrapper::InvokePlugin(
     grpc_status_code* status_code, const char** error_details) {
   std::multimap<grpc::string, grpc::string> metadata;
 
-  // const_cast is safe since the SecureAuthContext does not take owndership and
-  // the object is passed as a const ref to plugin_->GetMetadata.
+  // const_cast is safe since the SecureAuthContext only inc/dec the refcount
+  // and the object is passed as a const ref to plugin_->GetMetadata.
   SecureAuthContext cpp_channel_auth_context(
-      const_cast<grpc_auth_context*>(context.channel_auth_context), false);
+      const_cast<grpc_auth_context*>(context.channel_auth_context));
 
   Status status = plugin_->GetMetadata(context.service_url, context.method_name,
                                        cpp_channel_auth_context, &metadata);
diff --git a/src/cpp/client/secure_credentials.h b/src/cpp/client/secure_credentials.h
index 613f1d6dc2..4918bd5a4d 100644
--- a/src/cpp/client/secure_credentials.h
+++ b/src/cpp/client/secure_credentials.h
@@ -24,6 +24,7 @@
 #include <grpcpp/security/credentials.h>
 #include <grpcpp/support/config.h>
 
+#include "src/core/lib/security/credentials/credentials.h"
 #include "src/cpp/server/thread_pool_interface.h"
 
 namespace grpc {
@@ -31,7 +32,9 @@ namespace grpc {
 class SecureChannelCredentials final : public ChannelCredentials {
  public:
   explicit SecureChannelCredentials(grpc_channel_credentials* c_creds);
-  ~SecureChannelCredentials() { grpc_channel_credentials_release(c_creds_); }
+  ~SecureChannelCredentials() {
+    if (c_creds_ != nullptr) c_creds_->Unref();
+  }
   grpc_channel_credentials* GetRawCreds() { return c_creds_; }
 
   std::shared_ptr<grpc::Channel> CreateChannel(
@@ -51,7 +54,9 @@ class SecureChannelCredentials final : public ChannelCredentials {
 class SecureCallCredentials final : public CallCredentials {
  public:
   explicit SecureCallCredentials(grpc_call_credentials* c_creds);
-  ~SecureCallCredentials() { grpc_call_credentials_release(c_creds_); }
+  ~SecureCallCredentials() {
+    if (c_creds_ != nullptr) c_creds_->Unref();
+  }
   grpc_call_credentials* GetRawCreds() { return c_creds_; }
 
   bool ApplyToCall(grpc_call* call) override;