# rubocop:disable Style/StderrPuts

if RUBY_ENGINE != "ruby" || Gem.win_platform?
  $stderr.puts(
    "WARN: Skipping build of Datadog profiling loader. See Datadog profiling native extension note for details."
  )

  File.write("Makefile", "all install clean: # dummy makefile that does nothing")
  exit
end

require "mkmf"

# Because we can't control what compiler versions our customers use, shipping with -Werror by default is a no-go.
# But we can enable it in CI, so that we quickly spot any new warnings that just got introduced.
append_cflags "-Werror" if ENV["DATADOG_GEM_CI"] == "true"

# Older gcc releases may not default to C99 and we need to ask for this. This is also used:
# * by upstream Ruby -- search for gnu99 in the codebase
# * by msgpack, another datadog gem dependency
#   (https://github.com/msgpack/msgpack-ruby/blob/18ce08f6d612fe973843c366ac9a0b74c4e50599/ext/msgpack/extconf.rb#L8)
append_cflags "-std=gnu99"

# Gets really noisy when we include the MJIT header, let's omit it (TODO: Use #pragma GCC diagnostic instead?)
append_cflags "-Wno-unused-function"

# Allow defining variables at any point in a function
append_cflags "-Wno-declaration-after-statement"

# If we forget to include a Ruby header, the function call may still appear to work, but then
# cause a segfault later. Let's ensure that never happens.
append_cflags "-Werror-implicit-function-declaration"

# Warn on unused parameters to functions. Use `DDTRACE_UNUSED` to mark things as known-to-not-be-used.
append_cflags "-Wunused-parameter"

# The native extension is not intended to expose any symbols/functions for other native libraries to use;
# the sole exception being `Init_datadog_profiling_loader` which needs to be visible for Ruby to call it when
# it `dlopen`s the library.
#
# By setting this compiler flag, we tell it to assume that everything is private unless explicitly stated.
# For more details see https://gcc.gnu.org/wiki/Visibility
append_cflags "-fvisibility=hidden"

# Avoid legacy C definitions
append_cflags "-Wold-style-definition"

# Enable all other compiler warnings
append_cflags "-Wall"
append_cflags "-Wextra"

# Tag the native extension library with the Ruby version and Ruby platform.
# This makes it easier for development (avoids "oops I forgot to rebuild when I switched my Ruby") and ensures that
# the wrong library is never loaded.
# When requiring, we need to use the exact same string, including the version and the platform.
EXTENSION_NAME = "datadog_profiling_loader.#{RUBY_VERSION}_#{RUBY_PLATFORM}".freeze

create_makefile(EXTENSION_NAME)

# rubocop:enable Style/StderrPuts