Current File : //opt/alt/ruby33/share/ruby/prism/ffi.rb
# frozen_string_literal: true
# This file is responsible for mirroring the API provided by the C extension by
# using FFI to call into the shared library.
require "rbconfig"
require "ffi"
module Prism
BACKEND = :FFI
module LibRubyParser # :nodoc:
extend FFI::Library
# Define the library that we will be pulling functions from. Note that this
# must align with the build shared library from make/rake.
ffi_lib File.expand_path("../../build/libprism.#{RbConfig::CONFIG["SOEXT"]}", __dir__)
# Convert a native C type declaration into a symbol that FFI understands.
# For example:
#
# const char * -> :pointer
# bool -> :bool
# size_t -> :size_t
# void -> :void
#
def self.resolve_type(type)
type = type.strip
type.end_with?("*") ? :pointer : type.delete_prefix("const ").to_sym
end
# Read through the given header file and find the declaration of each of the
# given functions. For each one, define a function with the same name and
# signature as the C function.
def self.load_exported_functions_from(header, *functions)
File.foreach(File.expand_path("../../include/#{header}", __dir__)) do |line|
# We only want to attempt to load exported functions.
next unless line.start_with?("PRISM_EXPORTED_FUNCTION ")
# We only want to load the functions that we are interested in.
next unless functions.any? { |function| line.include?(function) }
# Parse the function declaration.
unless /^PRISM_EXPORTED_FUNCTION (?<return_type>.+) (?<name>\w+)\((?<arg_types>.+)\);$/ =~ line
raise "Could not parse #{line}"
end
# Delete the function from the list of functions we are looking for to
# mark it as having been found.
functions.delete(name)
# Split up the argument types into an array, ensure we handle the case
# where there are no arguments (by explicit void).
arg_types = arg_types.split(",").map(&:strip)
arg_types = [] if arg_types == %w[void]
# Resolve the type of the argument by dropping the name of the argument
# first if it is present.
arg_types.map! { |type| resolve_type(type.sub(/\w+$/, "")) }
# Attach the function using the FFI library.
attach_function name, arg_types, resolve_type(return_type)
end
# If we didn't find all of the functions, raise an error.
raise "Could not find functions #{functions.inspect}" unless functions.empty?
end
load_exported_functions_from(
"prism.h",
"pm_version",
"pm_serialize_parse",
"pm_serialize_parse_comments",
"pm_serialize_lex",
"pm_serialize_parse_lex",
"pm_parse_success_p"
)
load_exported_functions_from(
"prism/util/pm_buffer.h",
"pm_buffer_sizeof",
"pm_buffer_init",
"pm_buffer_value",
"pm_buffer_length",
"pm_buffer_free"
)
load_exported_functions_from(
"prism/util/pm_string.h",
"pm_string_mapped_init",
"pm_string_free",
"pm_string_source",
"pm_string_length",
"pm_string_sizeof"
)
# This object represents a pm_buffer_t. We only use it as an opaque pointer,
# so it doesn't need to know the fields of pm_buffer_t.
class PrismBuffer # :nodoc:
SIZEOF = LibRubyParser.pm_buffer_sizeof
attr_reader :pointer
def initialize(pointer)
@pointer = pointer
end
def value
LibRubyParser.pm_buffer_value(pointer)
end
def length
LibRubyParser.pm_buffer_length(pointer)
end
def read
value.read_string(length)
end
# Initialize a new buffer and yield it to the block. The buffer will be
# automatically freed when the block returns.
def self.with(&block)
pointer = FFI::MemoryPointer.new(SIZEOF)
begin
raise unless LibRubyParser.pm_buffer_init(pointer)
yield new(pointer)
ensure
LibRubyParser.pm_buffer_free(pointer)
pointer.free
end
end
end
# This object represents a pm_string_t. We only use it as an opaque pointer,
# so it doesn't have to be an FFI::Struct.
class PrismString # :nodoc:
SIZEOF = LibRubyParser.pm_string_sizeof
attr_reader :pointer
def initialize(pointer)
@pointer = pointer
end
def source
LibRubyParser.pm_string_source(pointer)
end
def length
LibRubyParser.pm_string_length(pointer)
end
def read
source.read_string(length)
end
# Yields a pm_string_t pointer to the given block.
def self.with(filepath, &block)
pointer = FFI::MemoryPointer.new(SIZEOF)
begin
raise unless LibRubyParser.pm_string_mapped_init(pointer, filepath)
yield new(pointer)
ensure
LibRubyParser.pm_string_free(pointer)
pointer.free
end
end
end
end
# Mark the LibRubyParser module as private as it should only be called through
# the prism module.
private_constant :LibRubyParser
# The version constant is set by reading the result of calling pm_version.
VERSION = LibRubyParser.pm_version.read_string
class << self
# Mirror the Prism.dump API by using the serialization API.
def dump(code, **options)
LibRubyParser::PrismBuffer.with do |buffer|
LibRubyParser.pm_serialize_parse(buffer.pointer, code, code.bytesize, dump_options(options))
buffer.read
end
end
# Mirror the Prism.dump_file API by using the serialization API.
def dump_file(filepath, **options)
LibRubyParser::PrismString.with(filepath) do |string|
dump(string.read, **options, filepath: filepath)
end
end
# Mirror the Prism.lex API by using the serialization API.
def lex(code, **options)
LibRubyParser::PrismBuffer.with do |buffer|
LibRubyParser.pm_serialize_lex(buffer.pointer, code, code.bytesize, dump_options(options))
Serialize.load_tokens(Source.new(code), buffer.read)
end
end
# Mirror the Prism.lex_file API by using the serialization API.
def lex_file(filepath, **options)
LibRubyParser::PrismString.with(filepath) do |string|
lex(string.read, **options, filepath: filepath)
end
end
# Mirror the Prism.parse API by using the serialization API.
def parse(code, **options)
Prism.load(code, dump(code, **options))
end
# Mirror the Prism.parse_file API by using the serialization API. This uses
# native strings instead of Ruby strings because it allows us to use mmap when
# it is available.
def parse_file(filepath, **options)
LibRubyParser::PrismString.with(filepath) do |string|
parse(string.read, **options, filepath: filepath)
end
end
# Mirror the Prism.parse_comments API by using the serialization API.
def parse_comments(code, **options)
LibRubyParser::PrismBuffer.with do |buffer|
LibRubyParser.pm_serialize_parse_comments(buffer.pointer, code, code.bytesize, dump_options(options))
source = Source.new(code)
loader = Serialize::Loader.new(source, buffer.read)
loader.load_header
loader.load_encoding
loader.load_start_line
loader.load_comments
end
end
# Mirror the Prism.parse_file_comments API by using the serialization
# API. This uses native strings instead of Ruby strings because it allows us
# to use mmap when it is available.
def parse_file_comments(filepath, **options)
LibRubyParser::PrismString.with(filepath) do |string|
parse_comments(string.read, **options, filepath: filepath)
end
end
# Mirror the Prism.parse_lex API by using the serialization API.
def parse_lex(code, **options)
LibRubyParser::PrismBuffer.with do |buffer|
LibRubyParser.pm_serialize_parse_lex(buffer.pointer, code, code.bytesize, dump_options(options))
source = Source.new(code)
loader = Serialize::Loader.new(source, buffer.read)
tokens = loader.load_tokens
node, comments, magic_comments, data_loc, errors, warnings = loader.load_nodes
tokens.each { |token,| token.value.force_encoding(loader.encoding) }
ParseResult.new([node, tokens], comments, magic_comments, data_loc, errors, warnings, source)
end
end
# Mirror the Prism.parse_lex_file API by using the serialization API.
def parse_lex_file(filepath, **options)
LibRubyParser::PrismString.with(filepath) do |string|
parse_lex(string.read, **options, filepath: filepath)
end
end
# Mirror the Prism.parse_success? API by using the serialization API.
def parse_success?(code, **options)
LibRubyParser.pm_parse_success_p(code, code.bytesize, dump_options(options))
end
# Mirror the Prism.parse_file_success? API by using the serialization API.
def parse_file_success?(filepath, **options)
LibRubyParser::PrismString.with(filepath) do |string|
parse_success?(string.read, **options, filepath: filepath)
end
end
private
# Convert the given options into a serialized options string.
def dump_options(options)
template = +""
values = []
template << "L"
if (filepath = options[:filepath])
values.push(filepath.bytesize, filepath.b)
template << "A*"
else
values << 0
end
template << "L"
values << options.fetch(:line, 1)
template << "L"
if (encoding = options[:encoding])
name = encoding.name
values.push(name.bytesize, name.b)
template << "A*"
else
values << 0
end
template << "C"
values << (options.fetch(:frozen_string_literal, false) ? 1 : 0)
template << "C"
values << (options.fetch(:verbose, true) ? 0 : 1)
template << "L"
if (scopes = options[:scopes])
values << scopes.length
scopes.each do |scope|
template << "L"
values << scope.length
scope.each do |local|
name = local.name
template << "L"
values << name.bytesize
template << "A*"
values << name.b
end
end
else
values << 0
end
values.pack(template)
end
end
end