Add a FileWriter interface (#7821)

* Add a FileWriter interface

* Change interface

* Provide 2 impl for File interface: FileManager & FileNameManager

* Update

* update

* Update

* Add file_writer file

* Update

* Format files

* Update based on review

* Update

* Format bzl file

* Add LoadFile function

* Format

---------

Co-authored-by: Derek Bailey <derekbailey@google.com>

include/flatbuffers/file_manager.h

@@ -0,0 +1,48 @@
+/*
+ * Copyright 2023 Google Inc. All rights reserved.
+ *
+ * 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 FLATBUFFERS_FILE_MANAGER_H_
+#define FLATBUFFERS_FILE_MANAGER_H_
+
+#include <set>
+#include <string>
+
+#include "flatbuffers/util.h"
+
+namespace flatbuffers {
+
+// A File interface to write data to file by default or
+// save only file names
+class FileManager {
+ public:
+  FileManager() = default;
+  virtual ~FileManager() = default;
+
+  virtual bool SaveFile(const std::string &absolute_file_name,
+                        const std::string &content) = 0;
+
+  virtual bool LoadFile(const std::string &absolute_file_name,
+                        std::string *buf) = 0;
+
+ private:
+  // Copying is not supported.
+  FileManager(const FileManager &) = delete;
+  FileManager &operator=(const FileManager &) = delete;
+};
+
+}  // namespace flatbuffers
+
+#endif  // FLATBUFFERS_FILE_MANAGER_H_

include/flatbuffers/flatbuffer_builder.h

@@ -1184,7 +1184,8 @@ class FlatBufferBuilder {
   // Allocates space for a vector of structures.
   // Must be completed with EndVectorOfStructs().
   template<typename T> T *StartVectorOfStructs(size_t vector_size) {
-    StartVector(vector_size * sizeof(T) / AlignOf<T>(), sizeof(T), AlignOf<T>());
+    StartVector(vector_size * sizeof(T) / AlignOf<T>(), sizeof(T),
+                AlignOf<T>());
     return reinterpret_cast<T *>(buf_.make_space(vector_size * sizeof(T)));
   }
 

include/flatbuffers/flatc.h

@@ -56,6 +56,7 @@ struct FlatCOptions {
   bool schema_binary = false;
   bool grpc_enabled = false;
   bool requires_bfbs = false;
+  bool file_names_only = false;
 
   std::vector<std::shared_ptr<CodeGenerator>> generators;
 };

include/flatbuffers/flexbuffers.h

@@ -1424,12 +1424,10 @@ class Builder FLATBUFFERS_FINAL_CLASS {
 
   template<typename T> static Type GetScalarType() {
     static_assert(flatbuffers::is_scalar<T>::value, "Unrelated types");
-    return flatbuffers::is_floating_point<T>::value
-               ? FBT_FLOAT
-               : flatbuffers::is_same<T, bool>::value
-                     ? FBT_BOOL
-                     : (flatbuffers::is_unsigned<T>::value ? FBT_UINT
-                                                           : FBT_INT);
+    return flatbuffers::is_floating_point<T>::value ? FBT_FLOAT
+           : flatbuffers::is_same<T, bool>::value
+               ? FBT_BOOL
+               : (flatbuffers::is_unsigned<T>::value ? FBT_UINT : FBT_INT);
   }
 
  public:

include/flatbuffers/minireflect.h

@@ -408,7 +408,7 @@ inline std::string FlatBufferToString(const uint8_t *buffer,
                                       const TypeTable *type_table,
                                       bool multi_line = false,
                                       bool vector_delimited = true,
-                                      const std::string& indent = "") {
+                                      const std::string &indent = "") {
   ToStringVisitor tostring_visitor(multi_line ? "\n" : " ", false, indent,
                                    vector_delimited);
   IterateFlatBuffer(buffer, type_table, &tostring_visitor);

include/flatbuffers/util.h

@@ -722,9 +722,10 @@ enum class Case {
   kSnake2 = 9,
 };
 
-// Convert the `input` string of case `input_case` to the specified `output_case`.
+// Convert the `input` string of case `input_case` to the specified
+// `output_case`.
 std::string ConvertCase(const std::string &input, Case output_case,
-                    Case input_case = Case::kSnake);
+                        Case input_case = Case::kSnake);
 
 }  // namespace flatbuffers