1 files changed, 106 insertions, 0 deletions
diff --git a/grpc/src/core/lib/service_config/service_config_parser.h b/grpc/src/core/lib/service_config/service_config_parser.h
new file mode 100644
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--- /dev/null
+++ b/grpc/src/core/lib/service_config/service_config_parser.h
@@ -0,0 +1,106 @@
+//
+// Copyright 2016 gRPC authors.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+//
+
+#ifndef GRPC_CORE_LIB_SERVICE_CONFIG_SERVICE_CONFIG_PARSER_H
+#define GRPC_CORE_LIB_SERVICE_CONFIG_SERVICE_CONFIG_PARSER_H
+
+#include <grpc/support/port_platform.h>
+
+#include <memory>
+#include <vector>
+
+#include <grpc/impl/codegen/grpc_types.h>
+
+#include "src/core/lib/iomgr/error.h"
+#include "src/core/lib/json/json.h"
+
+namespace grpc_core {
+
+// Service config parser registry.
+// See service_config.h for more information.
+class ServiceConfigParser {
+ public:
+  /// This is the base class that all service config parsers MUST use to store
+  /// parsed service config data.
+  class ParsedConfig {
+   public:
+    virtual ~ParsedConfig() = default;
+  };
+
+  /// This is the base class that all service config parsers should derive from.
+  class Parser {
+   public:
+    virtual ~Parser() = default;
+
+    virtual absl::string_view name() const = 0;
+
+    virtual std::unique_ptr<ParsedConfig> ParseGlobalParams(
+        const grpc_channel_args*, const Json& /* json */,
+        grpc_error_handle* error) {
+      // Avoid unused parameter warning on debug-only parameter
+      (void)error;
+      GPR_DEBUG_ASSERT(error != nullptr);
+      return nullptr;
+    }
+
+    virtual std::unique_ptr<ParsedConfig> ParsePerMethodParams(
+        const grpc_channel_args*, const Json& /* json */,
+        grpc_error_handle* error) {
+      // Avoid unused parameter warning on debug-only parameter
+      (void)error;
+      GPR_DEBUG_ASSERT(error != nullptr);
+      return nullptr;
+    }
+  };
+
+  using ServiceConfigParserList = std::vector<std::unique_ptr<Parser>>;
+  using ParsedConfigVector = std::vector<std::unique_ptr<ParsedConfig>>;
+
+  class Builder {
+   public:
+    /// Globally register a service config parser. Each new service config
+    /// update will go through all the registered parser. Each parser is
+    /// responsible for reading the service config json and returning a parsed
+    /// config.
+    void RegisterParser(std::unique_ptr<Parser> parser);
+
+    ServiceConfigParser Build();
+
+   private:
+    ServiceConfigParserList registered_parsers_;
+  };
+
+  ParsedConfigVector ParseGlobalParameters(const grpc_channel_args* args,
+                                           const Json& json,
+                                           grpc_error_handle* error) const;
+
+  ParsedConfigVector ParsePerMethodParameters(const grpc_channel_args* args,
+                                              const Json& json,
+                                              grpc_error_handle* error) const;
+
+  // Return the index for a given registered parser.
+  // If there is an error, return -1.
+  size_t GetParserIndex(absl::string_view name) const;
+
+ private:
+  explicit ServiceConfigParser(ServiceConfigParserList registered_parsers)
+      : registered_parsers_(std::move(registered_parsers)) {}
+  ServiceConfigParserList registered_parsers_;
+};
+
+}  // namespace grpc_core
+
+#endif /* GRPC_CORE_LIB_SERVICE_CONFIG_SERVICE_CONFIG_PARSER_H */