Add support for using array of scalar as key field in Cpp (#7623)

* add support for using array of scalar as key field

* update cmakelist and test.cpp to include the tests

* update bazel rule

* address comments

* clang format

* delete comment

* delete comment

* address the rest of the commnets

* address comments

* update naming in test file

* format build file

* buildifier

* make keycomparelessthan call keycomparewithvalue

* update to use flatbuffer array instead of raw pointer

* clang

* format

* revert format

* revert format

* update

* run generate_code.py

* run code generator

* revert changes by generate_code.py

* fist run make flatc and then run generate_code.py

Co-authored-by: Wen Sun <sunwen@google.com>

CMakeLists.txt

@@ -71,10 +71,10 @@ option(FLATBUFFERS_ENABLE_PCH
         Only work if CMake supports 'target_precompile_headers'. \"
         This can speed up compilation time."
        OFF)
-option(FLATBUFFERS_SKIP_MONSTER_EXTRA 
+option(FLATBUFFERS_SKIP_MONSTER_EXTRA
       "Skip generating monster_extra.fbs that contains non-supported numerical\"
       types." OFF)
-option(FLATBUFFERS_STRICT_MODE 
+option(FLATBUFFERS_STRICT_MODE
       "Build flatbuffers with all warnings as errors (-Werror or /WX)."
       OFF)
 
@@ -226,6 +226,7 @@ set(FlatBuffers_Tests_SRCS
   tests/flexbuffers_test.cpp
   tests/fuzz_test.cpp
   tests/json_test.cpp
+  tests/key_field_test.cpp
   tests/monster_test.cpp
   tests/optional_scalars_test.cpp
   tests/parser_test.cpp
@@ -264,6 +265,8 @@ set(FlatBuffers_Tests_SRCS
   ${CMAKE_CURRENT_BINARY_DIR}/tests/native_inline_table_test_generated.h
   # file generate by running compiler on tests/alignment_test.fbs
   ${CMAKE_CURRENT_BINARY_DIR}/tests/alignment_test_generated.h
+  # file generate by running compiler on tests/key_field/key_field_sample.fbs
+  ${CMAKE_CURRENT_BINARY_DIR}/tests/key_field/key_field_sample_generated.h
 )
 
 set(FlatBuffers_Tests_CPP17_SRCS
@@ -365,8 +368,8 @@ include_directories(grpc)
 
 # Creates an interface library that stores the configuration settings that each
 # target links too. This is a compromise between setting configuration globally
-# with add_compile_options() and the more targetted target_compile_options(). 
-# This way each target in this file can share settings and override them if 
+# with add_compile_options() and the more targetted target_compile_options().
+# This way each target in this file can share settings and override them if
 # needed.
 add_library(ProjectConfig INTERFACE)
 target_compile_features(ProjectConfig
@@ -382,7 +385,7 @@ set(CMAKE_CXX_EXTENSIONS OFF)
 
 if(MSVC_LIKE)
   target_compile_options(ProjectConfig
-    INTERFACE 
+    INTERFACE
       /W4
       $<$<BOOL:${FLATBUFFERS_STRICT_MODE}>:
         /WX       # Treat all compiler warnings as errors
@@ -414,8 +417,8 @@ else()
           -Wno-error=stringop-overflow
         >
       >
-      -pedantic 
-      -Wextra 
+      -pedantic
+      -Wextra
       -Wno-unused-parameter
       -Wold-style-cast
       -fsigned-char
@@ -429,7 +432,7 @@ else()
         $<$<VERSION_GREATER:$<CXX_COMPILER_VERSION>,3.8>:
           -Wimplicit-fallthrough
           -Wextra-semi
-          $<$<BOOL:${FLATBUFFERS_STRICT_MODE}>:            
+          $<$<BOOL:${FLATBUFFERS_STRICT_MODE}>:
             -Werror=unused-private-field
           >
         >
@@ -438,7 +441,7 @@ else()
       $<$<CXX_COMPILER_ID:GNU>:
         $<$<VERSION_GREATER:$<CXX_COMPILER_VERSION>,4.4>:
           -Wunused-result
-          -Wunused-parameter 
+          -Wunused-parameter
           -Werror=unused-parameter
           -Wmissing-declarations
         >
@@ -446,7 +449,7 @@ else()
           -Wzero-as-null-pointer-constant
         >
         $<$<VERSION_GREATER:$<CXX_COMPILER_VERSION>,7.0>:
-          -faligned-new 
+          -faligned-new
           $<$<BOOL:${FLATBUFFERS_STRICT_MODE}>:
             -Werror=implicit-fallthrough=2
           >
@@ -476,7 +479,7 @@ if(FLATBUFFERS_BUILD_FLATLIB)
   add_library(flatbuffers STATIC ${FlatBuffers_Library_SRCS})
 
   # Attach header directory for when build via add_subdirectory().
-  target_include_directories(flatbuffers 
+  target_include_directories(flatbuffers
     INTERFACE
       $<BUILD_INTERFACE:${CMAKE_CURRENT_SOURCE_DIR}/include>
   )
@@ -494,7 +497,7 @@ if(FLATBUFFERS_BUILD_FLATC)
   endif()
 
   target_link_libraries(flatc PRIVATE $<BUILD_INTERFACE:ProjectConfig>)
-  target_compile_options(flatc 
+  target_compile_options(flatc
     PUBLIC
       $<$<AND:$<BOOL:${MSVC_LIKE}>,$<CONFIG:Release>>:
         /MT
@@ -696,13 +699,13 @@ if(FLATBUFFERS_BUILD_GRPCTEST)
   find_package(gRPC CONFIG REQUIRED)
   add_executable(grpctest ${FlatBuffers_GRPCTest_SRCS})
   add_dependencies(grpctest generated_code)
-  target_link_libraries(grpctext 
-    PRIVATE 
+  target_link_libraries(grpctext
+    PRIVATE
       $<BUILD_INTERFACE:ProjectConfig>
-      gRPC::grpc++_unsecure 
-      gRPC::gpr 
+      gRPC::grpc++_unsecure
+      gRPC::gpr
       pthread
-      dl 
+      dl
   )
 endif()
 
@@ -715,8 +718,8 @@ if(FLATBUFFERS_INSTALL)
 
   configure_file(CMake/flatbuffers-config-version.cmake.in flatbuffers-config-version.cmake @ONLY)
   install(
-      FILES 
-        "CMake/flatbuffers-config.cmake" 
+      FILES
+        "CMake/flatbuffers-config.cmake"
         "CMake/BuildFlatBuffers.cmake"
         "${CMAKE_CURRENT_BINARY_DIR}/flatbuffers-config-version.cmake"
       DESTINATION ${FB_CMAKE_DIR}