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# frozen_string_literal: true
module SassC
class FunctionsHandler
def initialize(options)
@options = options
end
def setup(native_options, functions: Script::Functions)
@callbacks = {}
@function_names = {}
list = Native.make_function_list(Script.custom_functions(functions: functions).count)
# use an anonymous class wrapper to avoid mutations in a threaded environment
functions_wrapper = Class.new do
attr_accessor :options
include functions
end.new
functions_wrapper.options = @options
Script.custom_functions(functions: functions).each_with_index do |custom_function, i|
@callbacks[custom_function] = FFI::Function.new(:pointer, [:pointer, :pointer]) do |native_argument_list, cookie|
begin
function_arguments = arguments_from_native_list(native_argument_list)
result = functions_wrapper.send(custom_function, *function_arguments)
to_native_value(result)
rescue StandardError => exception
# This rescues any exceptions that occur either in value conversion
# or during the execution of a custom function.
error(exception.message)
end
end
@function_names[custom_function] = Script.formatted_function_name(custom_function, functions: functions)
callback = Native.make_function(
@function_names[custom_function],
@callbacks[custom_function],
nil
)
Native::function_set_list_entry(list, i, callback)
end
Native::option_set_c_functions(native_options, list)
end
private
def arguments_from_native_list(native_argument_list)
native_argument_list_length = Native.list_get_length(native_argument_list)
(0...native_argument_list_length).map do |i|
native_value = Native.list_get_value(native_argument_list, i)
Script::ValueConversion.from_native(native_value, @options)
end.compact
end
def to_native_value(sass_value)
# if the custom function returns nil, we provide a "default" return
# value of an empty string
sass_value ||= SassC::Script::Value::String.new("")
sass_value.options = @options
Script::ValueConversion.to_native(sass_value)
end
def error(message)
$stderr.puts "[SassC::FunctionsHandler] #{message}"
Native.make_error(message)
end
end
end
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