Convert retry throttle code to C++ and add tests.

1 files changed, 50 insertions, 25 deletions

diff --git a/src/core/ext/filters/client_channel/retry_throttle.h b/src/core/ext/filters/client_channel/retry_throttle.h
index 0505fc27f2..2b6fa0a70b 100644
--- a/src/core/ext/filters/client_channel/retry_throttle.h
+++ b/src/core/ext/filters/client_channel/retry_throttle.h
@@ -21,32 +21,57 @@
 
 #include <grpc/support/port_platform.h>
 
-#include <stdbool.h>
+#include "src/core/lib/gprpp/ref_counted.h"
+
+namespace grpc_core {
+namespace internal {
 
 /// Tracks retry throttling data for an individual server name.
-typedef struct grpc_server_retry_throttle_data grpc_server_retry_throttle_data;
-
-/// Records a failure.  Returns true if it's okay to send a retry.
-bool grpc_server_retry_throttle_data_record_failure(
-    grpc_server_retry_throttle_data* throttle_data);
-/// Records a success.
-void grpc_server_retry_throttle_data_record_success(
-    grpc_server_retry_throttle_data* throttle_data);
-
-grpc_server_retry_throttle_data* grpc_server_retry_throttle_data_ref(
-    grpc_server_retry_throttle_data* throttle_data);
-void grpc_server_retry_throttle_data_unref(
-    grpc_server_retry_throttle_data* throttle_data);
-
-/// Initializes global map of failure data for each server name.
-void grpc_retry_throttle_map_init();
-/// Shuts down global map of failure data for each server name.
-void grpc_retry_throttle_map_shutdown();
-
-/// Returns a reference to the failure data for \a server_name, creating
-/// a new entry if needed.
-/// Caller must eventually unref via \a grpc_server_retry_throttle_data_unref().
-grpc_server_retry_throttle_data* grpc_retry_throttle_map_get_data_for_server(
-    const char* server_name, int max_milli_tokens, int milli_token_ratio);
+class ServerRetryThrottleData : public RefCounted<ServerRetryThrottleData> {
+ public:
+  ServerRetryThrottleData(intptr_t max_milli_tokens, intptr_t milli_token_ratio,
+                          ServerRetryThrottleData* old_throttle_data);
+
+  /// Records a failure.  Returns true if it's okay to send a retry.
+  bool RecordFailure();
+
+  /// Records a success.
+  void RecordSuccess();
+
+  intptr_t max_milli_tokens() const { return max_milli_tokens_; }
+  intptr_t milli_token_ratio() const { return milli_token_ratio_; }
+
+ private:
+  ~ServerRetryThrottleData();
+
+  void GetReplacementThrottleDataIfNeeded(
+      ServerRetryThrottleData** throttle_data);
+
+  const intptr_t max_milli_tokens_;
+  const intptr_t milli_token_ratio_;
+  gpr_atm milli_tokens_;
+  // A pointer to the replacement for this ServerRetryThrottleData entry.
+  // If non-nullptr, then this entry is stale and must not be used.
+  // We hold a reference to the replacement.
+  gpr_atm replacement_ = 0;
+};
+
+/// Global map of server name to retry throttle data.
+class ServerRetryThrottleMap {
+ public:
+  /// Initializes global map of failure data for each server name.
+  static void Init();
+  /// Shuts down global map of failure data for each server name.
+  static void Shutdown();
+
+  /// Returns the failure data for \a server_name, creating a new entry if
+  /// needed.
+  static RefCountedPtr<ServerRetryThrottleData> GetDataForServer(
+      const char* server_name, intptr_t max_milli_tokens,
+      intptr_t milli_token_ratio);
+};
+
+}  // namespace internal
+}  // namespace grpc_core
 
 #endif /* GRPC_CORE_EXT_FILTERS_CLIENT_CHANNEL_RETRY_THROTTLE_H */