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# regarding copyright ownership.  The ASF licenses this file
# to you 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.
##############################################################################

# Find FLATBUFFERS (flatbuffers/include, libflatbuffers.a, flatc)
# This module defines:
# FLATBUFFERS_INCLUDE_DIR, directory containing headers
# FLATBUFFERS_STATIC_LIB, path to flatbuffers's static library
# FLATBUFFERS_COMPILER, path to flatc compiler
#
# TODO: [01-15-2021] now that we use Flatbuffers on all platforms, it might be
# a good time to figure out how we can install Flatbuffers as a dependency
# inside our CMakeLists (we would just need to build the flatc executable
# before our Arrow build starts). Right now, I've put in some hacks to make
# sure our Windows build works on Azure by pre-installing flatc (like we do on
# all other platforms), and then pulling down the headers for Windows so they
# can be included.

# this might fail
# https://gitlab.kitware.com/cmake/cmake/issues/19120
if (WIN32)
  find_path(FLATBUFFERS_INCLUDE_DIR flatbuffers/flatbuffers.h
    PATHS ${FLATBUFFERS_ROOT}/include)

  find_program(FLATBUFFERS_COMPILER flatc
    PATHS ${FLATBUFFERS_ROOT}/bin)
else()
  find_path(FLATBUFFERS_INCLUDE_DIR flatbuffers/flatbuffers.h
    PATHS ${FLATBUFFERS_ROOT}/include
    HINTS /usr/local /usr/local/flatbuffers /usr/local/Homebrew /usr ~/homebrew/ /usr/local/include /usr/local/flatbuffers/include /usr/include ~/homebrew/include
    NO_CMAKE_SYSTEM_PATH
    NO_SYSTEM_ENVIRONMENT_PATH)

  find_program(FLATBUFFERS_COMPILER flatc
    PATHS ${FLATBUFFERS_ROOT}/bin
    HINTS /usr/local/bin /usr/bin /usr/local/Homebrew/bin ~/homebrew/bin
    NO_CMAKE_SYSTEM_PATH
    NO_SYSTEM_ENVIRONMENT_PATH)

  if(NOT ${FLATBUFFERS_INCLUDE_DIR})
    # HACK
    set(FLATBUFFERS_INCLUDE_DIR /usr/local/include)
  endif()
endif()

include(FindPackageHandleStandardArgs)

if (WIN32)
  find_package_handle_standard_args(Flatbuffers REQUIRED_VARS
    FLATBUFFERS_INCLUDE_DIR FLATBUFFERS_COMPILER)
else()
  find_package_handle_standard_args(FLATBUFFERS REQUIRED_VARS
    FLATBUFFERS_INCLUDE_DIR FLATBUFFERS_COMPILER)
endif()