add c api bindings for lgraph (#180)

* add c bindings of lgraph api

* add license

* fix cpplint typo

* fix typo

* add lgraph-cbindings ut

* fix cpplint

* fix test_c

* default initialize

* fix cpplint

* always compile c bindings

* "pack" c bindings into lgraph target

* move src/c/c.cpp to src/lgraph_api/c.cpp

* Update Options.cmake

* Update src/BuildLGraphApi.cmake

---------

Co-authored-by: Tao Wang <wangtaofighting@163.com>

include/lgraph/lgraph_types.h

@@ -1,4 +1,4 @@
-/**
+/**
  * Copyright 2022 AntGroup CO., Ltd.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
@@ -726,9 +726,7 @@ struct FieldData {
 
     FieldType type;
 
-    FieldType getType() const {
-        return type;
-    }
+    FieldType GetType() const { return type; }
 
     union {
         bool boolean;
@@ -759,9 +757,27 @@ struct FieldData {
     /** @brief   Query if this object is string */
     bool IsString() const { return type == FieldType::STRING; }
 
+    /** @brief   Query if this object is INT8 */
+    bool IsInt8() const { return type == FieldType::INT8; }
+
+    /** @brief   Query if this object is INT16 */
+    bool IsInt16() const { return type == FieldType::INT16; }
+
+    /** @brief   Query if this object is INT32 */
+    bool IsInt32() const { return type == FieldType::INT32; }
+
+    /** @brief   Query if this object is INT64 */
+    bool IsInt64() const { return type == FieldType::INT64; }
+
     /** @brief   Is this a INT8, INT16, INT32 or INT64? */
     bool IsInteger() const { return IsInteger(type); }
 
+    /** @brief   Query if this object is float */
+    bool IsFloat() const { return type == FieldType::FLOAT; }
+
+    /** @brief   Query if this object is double */
+    bool IsDouble() const { return type == FieldType::DOUBLE; }
+
     /** @brief   Is this a FLOAT or DOUBLE? */
     bool IsReal() const { return IsReal(type); }
 
@@ -799,7 +815,7 @@ struct FieldSpec {
     /** @brief   is this field optional? */
     bool optional;
 
-    FieldSpec() {}
+    FieldSpec(): name(), type(FieldType::NUL), optional(false) {}
 
     /**
      * @brief   Constructor

src/BuildLGraphApi.cmake

@@ -63,6 +63,7 @@ set(LGRAPH_DB_SRC
         db/token_manager.cpp)
 
 set(LGRAPH_API_SRC
+        lgraph_api/c.cpp
         lgraph_api/lgraph_db.cpp
         lgraph_api/lgraph_edge_iterator.cpp
         lgraph_api/lgraph_galaxy.cpp

src/import/import_v3.cpp

@@ -32,7 +32,7 @@ void Importer::OnErrorOffline(const std::string& msg) {
 }
 
 void Importer::AppendFieldData(std::string& ret, const FieldData& data) {
-    switch (data.getType()) {
+    switch (data.GetType()) {
     case FieldType::NUL:
         FMA_ASSERT(false);
         break;