[clang][extract-api] Refactor ExtractAPI and improve docs

- The name SymbolGraph is inappropriate and confusing for the new library
  for clang-extract-api. Refactor and rename things to make it clear that
  ExtractAPI is the core functionality and SymbolGraph is one serializer
  for the API information.
- Add documentation comments to ExtractAPI classes and methods to improve
  readability and clearness of the ExtractAPI work.

Differential Revision: https://reviews.llvm.org/D122160

1 files changed, 19 insertions, 0 deletions

diff --git a/clang/lib/ExtractAPI/Serialization/SerializerBase.cpp b/clang/lib/ExtractAPI/Serialization/SerializerBase.cpp
new file mode 100644
index 0000000..71fd25b
--- /dev/null
+++ b/clang/lib/ExtractAPI/Serialization/SerializerBase.cpp
@@ -0,0 +1,19 @@
+//===- ExtractAPI/Serialization/SerializerBase.cpp --------------*- C++ -*-===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+///
+/// \file
+/// This file implements the APISerializer interface.
+///
+//===----------------------------------------------------------------------===//
+
+#include "clang/ExtractAPI/Serialization/SerializerBase.h"
+#include "llvm/Support/raw_ostream.h"
+
+using namespace clang::extractapi;
+
+void APISerializer::serialize(llvm::raw_ostream &os) {}