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Diffstat (limited to 'lib/prism/ffi.rb')
| -rw-r--r-- | lib/prism/ffi.rb | 611 |
1 files changed, 611 insertions, 0 deletions
diff --git a/lib/prism/ffi.rb b/lib/prism/ffi.rb new file mode 100644 index 0000000000..6b9bde51ea --- /dev/null +++ b/lib/prism/ffi.rb @@ -0,0 +1,611 @@ +# frozen_string_literal: true +# :markup: markdown +# typed: ignore + +# 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" + +# We want to eagerly load this file if there are Ractors so that it does not get +# autoloaded from within a non-main Ractor. +require "prism/serialize" if defined?(Ractor) + +module Prism # :nodoc: + 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. + libprism_in_build = File.expand_path("../../build/libprism.#{RbConfig::CONFIG["SOEXT"]}", __dir__) + libprism_in_libdir = "#{RbConfig::CONFIG["libdir"]}/prism/libprism.#{RbConfig::CONFIG["SOEXT"]}" + + if File.exist?(libprism_in_build) + INCLUDE_DIR = File.expand_path("../../include", __dir__) + ffi_lib libprism_in_build + else + INCLUDE_DIR = "#{RbConfig::CONFIG["libdir"]}/prism/include" + ffi_lib libprism_in_libdir + end + + # 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, callbacks) + type = type.strip + + if !type.end_with?("*") + type.delete_prefix("const ").to_sym + else + type = type.delete_suffix("*").rstrip + callbacks.include?(type.to_sym) ? type.to_sym : :pointer + end + 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, callbacks) + File.foreach("#{INCLUDE_DIR}/#{header}") 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) } + + # Strip trailing attributes (PRISM_NODISCARD, PRISM_NONNULL(...), etc.) + line = line.sub(/\)(\s+PRISM_\w+(?:\([^)]*\))?)+\s*;/, ");") + + # Parse the function declaration. + unless /^PRISM_EXPORTED_FUNCTION (?<return_type>.+) (?<name>\w+)\((?<arg_types>.+)\);$/ =~ line + raise "Could not parse #{line}" + end + + # Delete the function from the list of functions we are looking for to + # mark it as having been found. + functions.delete(name) + + # Split up the argument types into an array, ensure we handle the case + # where there are no arguments (by explicit void). + arg_types = arg_types.split(",").map(&:strip) + arg_types = [] if arg_types == %w[void] + + # Resolve the type of the argument by dropping the name of the argument + # first if it is present. + arg_types.map! { |type| resolve_type(type.sub(/\w+$/, ""), callbacks) } + + # 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 + + callback :pm_source_stream_fgets_t, [:pointer, :int, :pointer], :pointer + callback :pm_source_stream_feof_t, [:pointer], :int + pm_source_init_result_values = %i[PM_SOURCE_INIT_SUCCESS PM_SOURCE_INIT_ERROR_GENERIC PM_SOURCE_INIT_ERROR_DIRECTORY PM_SOURCE_INIT_ERROR_NON_REGULAR] + enum :pm_source_init_result_t, pm_source_init_result_values + enum :pm_string_query_t, [:PM_STRING_QUERY_ERROR, -1, :PM_STRING_QUERY_FALSE, :PM_STRING_QUERY_TRUE] + + # Ractor-safe lookup table for pm_source_init_result_t, since FFI's + # enum_type accesses module instance variables that are not shareable. + SOURCE_INIT_RESULT = pm_source_init_result_values.freeze + + load_exported_functions_from( + "prism/version.h", + "pm_version", + [] + ) + + load_exported_functions_from( + "prism/serialize.h", + "pm_serialize_parse", + "pm_serialize_parse_stream", + "pm_serialize_parse_comments", + "pm_serialize_lex", + "pm_serialize_parse_lex", + "pm_serialize_parse_success_p", + [] + ) + + load_exported_functions_from( + "prism/string_query.h", + "pm_string_query_local", + "pm_string_query_constant", + "pm_string_query_method_name", + [] + ) + + load_exported_functions_from( + "prism/buffer.h", + "pm_buffer_new", + "pm_buffer_value", + "pm_buffer_length", + "pm_buffer_free", + [] + ) + + load_exported_functions_from( + "prism/source.h", + "pm_source_file_new", + "pm_source_mapped_new", + "pm_source_stream_new", + "pm_source_free", + "pm_source_source", + "pm_source_length", + [:pm_source_stream_fgets_t, :pm_source_stream_feof_t] + ) + + # 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: + 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 + buffer = LibRubyParser.pm_buffer_new + raise unless buffer + + begin + yield new(buffer) + ensure + LibRubyParser.pm_buffer_free(buffer) + end + end + end + + # This object represents source code to be parsed. For strings it wraps a + # pointer directly; for files it uses a pm_source_t under the hood. + class PrismSource # :nodoc: + PLATFORM_EXPECTS_UTF8 = + RbConfig::CONFIG["host_os"].match?(/bccwin|cygwin|djgpp|mingw|mswin|wince|darwin/i) + + attr_reader :pointer, :length + + def initialize(pointer, length, from_string) + @pointer = pointer + @length = length + @from_string = from_string + end + + def read + raise "should use the original String instead" if @from_string + @pointer.read_string(@length) + end + + # Yields a PrismSource backed by the given string to the block. + def self.with_string(string) + raise TypeError unless string.is_a?(String) + + length = string.bytesize + # + 1 to never get an address of 0, which pm_parser_init() asserts + FFI::MemoryPointer.new(:char, length + 1, false) do |pointer| + pointer.write_string(string) + # since we have the extra byte we might as well \0-terminate + pointer.put_char(length, 0) + return yield new(pointer, length, true) + end + end + + # Yields a PrismSource to the given block, backed by a pm_source_t. + def self.with_file(filepath) + raise TypeError unless filepath.is_a?(String) + + # On Windows and Mac, it's expected that filepaths will be encoded in + # UTF-8. If they are not, we need to convert them to UTF-8 before + # passing them into pm_source_mapped_new. + if PLATFORM_EXPECTS_UTF8 && (encoding = filepath.encoding) != Encoding::ASCII_8BIT && encoding != Encoding::UTF_8 + filepath = filepath.encode(Encoding::UTF_8) + end + + FFI::MemoryPointer.new(:int) do |result_ptr| + pm_source = LibRubyParser.pm_source_mapped_new(filepath, 0, result_ptr) + + case SOURCE_INIT_RESULT[result_ptr.read_int] + when :PM_SOURCE_INIT_SUCCESS + pointer = LibRubyParser.pm_source_source(pm_source) + length = LibRubyParser.pm_source_length(pm_source) + return yield new(pointer, length, false) + when :PM_SOURCE_INIT_ERROR_GENERIC + raise SystemCallError.new(filepath, FFI.errno) + when :PM_SOURCE_INIT_ERROR_DIRECTORY + raise Errno::EISDIR.new(filepath) + when :PM_SOURCE_INIT_ERROR_NON_REGULAR + # Fall back to reading the file through Ruby IO for non-regular + # files (pipes, character devices, etc.) + return with_string(File.read(filepath)) { |string| yield string } + else + raise "Unknown error initializing pm_source_t: #{result_ptr.read_int}" + end + ensure + LibRubyParser.pm_source_free(pm_source) if pm_source && !pm_source.null? + 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.freeze + + class << self + # Mirror the Prism.dump API by using the serialization API. + def dump(source, **options) + LibRubyParser::PrismSource.with_string(source) { |string| dump_common(string, options) } + end + + # Mirror the Prism.dump_file API by using the serialization API. + def dump_file(filepath, **options) + options[:filepath] = filepath + LibRubyParser::PrismSource.with_file(filepath) { |string| dump_common(string, options) } + end + + # Mirror the Prism.lex API by using the serialization API. + def lex(code, **options) + LibRubyParser::PrismSource.with_string(code) { |string| lex_common(string, code, options) } + end + + # Mirror the Prism.lex_file API by using the serialization API. + def lex_file(filepath, **options) + options[:filepath] = filepath + LibRubyParser::PrismSource.with_file(filepath) { |string| lex_common(string, string.read, options) } + end + + # Mirror the Prism.parse API by using the serialization API. + def parse(code, **options) + LibRubyParser::PrismSource.with_string(code) { |string| parse_common(string, 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) + options[:filepath] = filepath + LibRubyParser::PrismSource.with_file(filepath) { |string| parse_common(string, string.read, options) } + end + + # Mirror the Prism.parse_stream API by using the serialization API. + def parse_stream(stream, **options) + LibRubyParser::PrismBuffer.with do |buffer| + source = +"" + callback = -> (string, size, _) { + raise "Expected size to be >= 0, got: #{size}" if size <= 0 + + if !(line = stream.gets(size - 1)).nil? + source << line + string.write_string("#{line}\x00", line.bytesize + 1) + end + } + + eof_callback = -> (_) { stream.eof? } + + pm_source = LibRubyParser.pm_source_stream_new(nil, callback, eof_callback) + begin + LibRubyParser.pm_serialize_parse_stream(buffer.pointer, pm_source, dump_options(options)) + Prism.load(source, buffer.read, options.fetch(:freeze, false)) + ensure + LibRubyParser.pm_source_free(pm_source) if pm_source && !pm_source.null? + end + end + end + + # Mirror the Prism.parse_comments API by using the serialization API. + def parse_comments(code, **options) + LibRubyParser::PrismSource.with_string(code) { |string| parse_comments_common(string, code, options) } + 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) + options[:filepath] = filepath + LibRubyParser::PrismSource.with_file(filepath) { |string| parse_comments_common(string, string.read, options) } + end + + # Mirror the Prism.parse_lex API by using the serialization API. + def parse_lex(code, **options) + LibRubyParser::PrismSource.with_string(code) { |string| parse_lex_common(string, code, options) } + end + + # Mirror the Prism.parse_lex_file API by using the serialization API. + def parse_lex_file(filepath, **options) + options[:filepath] = filepath + LibRubyParser::PrismSource.with_file(filepath) { |string| parse_lex_common(string, string.read, options) } + end + + # Mirror the Prism.parse_success? API by using the serialization API. + def parse_success?(code, **options) + LibRubyParser::PrismSource.with_string(code) { |string| parse_file_success_common(string, options) } + end + + # Mirror the Prism.parse_failure? API by using the serialization API. + def parse_failure?(code, **options) + !parse_success?(code, **options) + end + + # Mirror the Prism.parse_file_success? API by using the serialization API. + def parse_file_success?(filepath, **options) + options[:filepath] = filepath + LibRubyParser::PrismSource.with_file(filepath) { |string| parse_file_success_common(string, options) } + end + + # Mirror the Prism.parse_file_failure? API by using the serialization API. + def parse_file_failure?(filepath, **options) + !parse_file_success?(filepath, **options) + end + + # Mirror the Prism.profile API by using the serialization API. + def profile(source, **options) + LibRubyParser::PrismSource.with_string(source) do |string| + LibRubyParser::PrismBuffer.with do |buffer| + LibRubyParser.pm_serialize_parse(buffer.pointer, string.pointer, string.length, dump_options(options)) + nil + end + end + end + + # Mirror the Prism.profile_file API by using the serialization API. + def profile_file(filepath, **options) + LibRubyParser::PrismSource.with_file(filepath) do |string| + LibRubyParser::PrismBuffer.with do |buffer| + options[:filepath] = filepath + LibRubyParser.pm_serialize_parse(buffer.pointer, string.pointer, string.length, dump_options(options)) + nil + end + end + end + + private + + def dump_common(string, options) # :nodoc: + LibRubyParser::PrismBuffer.with do |buffer| + LibRubyParser.pm_serialize_parse(buffer.pointer, string.pointer, string.length, dump_options(options)) + + dumped = buffer.read + dumped.freeze if options.fetch(:freeze, false) + + dumped + end + end + + def lex_common(string, code, options) # :nodoc: + LibRubyParser::PrismBuffer.with do |buffer| + LibRubyParser.pm_serialize_lex(buffer.pointer, string.pointer, string.length, dump_options(options)) + Serialize.load_lex(code, buffer.read, options.fetch(:freeze, false)) + end + end + + def parse_common(string, code, options) # :nodoc: + serialized = dump_common(string, options) + Serialize.load_parse(code, serialized, options.fetch(:freeze, false)) + end + + def parse_comments_common(string, code, options) # :nodoc: + LibRubyParser::PrismBuffer.with do |buffer| + LibRubyParser.pm_serialize_parse_comments(buffer.pointer, string.pointer, string.length, dump_options(options)) + Serialize.load_parse_comments(code, buffer.read, options.fetch(:freeze, false)) + end + end + + def parse_lex_common(string, code, options) # :nodoc: + LibRubyParser::PrismBuffer.with do |buffer| + LibRubyParser.pm_serialize_parse_lex(buffer.pointer, string.pointer, string.length, dump_options(options)) + Serialize.load_parse_lex(code, buffer.read, options.fetch(:freeze, false)) + end + end + + def parse_file_success_common(string, options) # :nodoc: + LibRubyParser.pm_serialize_parse_success_p(string.pointer, string.length, dump_options(options)) + end + + # Return the value that should be dumped for the command_line option. + def dump_options_command_line(options) + command_line = options.fetch(:command_line, "") + raise ArgumentError, "command_line must be a string" unless command_line.is_a?(String) + + command_line.each_char.inject(0) do |value, char| + case char + when "a" then value | 0b000001 + when "e" then value | 0b000010 + when "l" then value | 0b000100 + when "n" then value | 0b001000 + when "p" then value | 0b010000 + when "x" then value | 0b100000 + else raise ArgumentError, "invalid command_line option: #{char}" + end + end + end + + # Return the value that should be dumped for the version option. + def dump_options_version(version) + case version + when "current" + version_string_to_number(RUBY_VERSION) || raise(CurrentVersionError, RUBY_VERSION) + when "latest", nil + 0 # Handled in pm_parser_init + when "nearest" + dump = version_string_to_number(RUBY_VERSION) + return dump if dump + if RUBY_VERSION < "3.3" + version_string_to_number("3.3") + else + 0 # Handled in pm_parser_init + end + else + version_string_to_number(version) || raise(ArgumentError, "invalid version: #{version}") + end + end + + # Converts a version string like "4.0.0" or "4.0" into a number. + # Returns nil if the version is unknown. + def version_string_to_number(version) + case version + when /\A3\.3(\.\d+)?\z/ + 1 + when /\A3\.4(\.\d+)?\z/ + 2 + when /\A3\.5(\.\d+)?\z/, /\A4\.0(\.\d+)?\z/ + 3 + when /\A4\.1(\.\d+)?\z/ + 4 + end + end + + # 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.is_a?(Encoding) ? encoding.name : encoding + 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 << dump_options_command_line(options) + + template << "C" + values << dump_options_version(options[:version]) + + template << "C" + values << (options[:encoding] == false ? 1 : 0) + + template << "C" + values << (options.fetch(:main_script, false) ? 1 : 0) + + template << "C" + values << (options.fetch(:partial_script, false) ? 1 : 0) + + template << "C" + values << (options.fetch(:freeze, false) ? 1 : 0) + + template << "L" + if (scopes = options[:scopes]) + values << scopes.length + + scopes.each do |scope| + locals = nil + forwarding = 0 + + case scope + when Array + locals = scope + when Scope + locals = scope.locals + + scope.forwarding.each do |forward| + case forward + when :* then forwarding |= 0x1 + when :** then forwarding |= 0x2 + when :& then forwarding |= 0x4 + when :"..." then forwarding |= 0x8 + else raise ArgumentError, "invalid forwarding value: #{forward}" + end + end + else + raise TypeError, "wrong argument type #{scope.class.inspect} (expected Array or Prism::Scope)" + end + + template << "L" + values << locals.length + + template << "C" + values << forwarding + + locals.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 + + # Here we are going to patch StringQuery to put in the class-level methods so + # that it can maintain a consistent interface + class StringQuery # :nodoc: + class << self + # Mirrors the C extension's StringQuery::local? method. + def local?(string) + query(LibRubyParser.pm_string_query_local(string, string.bytesize, string.encoding.name)) + end + + # Mirrors the C extension's StringQuery::constant? method. + def constant?(string) + query(LibRubyParser.pm_string_query_constant(string, string.bytesize, string.encoding.name)) + end + + # Mirrors the C extension's StringQuery::method_name? method. + def method_name?(string) + query(LibRubyParser.pm_string_query_method_name(string, string.bytesize, string.encoding.name)) + end + + private + + # Parse the enum result and return an appropriate boolean. + def query(result) + case result + when :PM_STRING_QUERY_ERROR + raise ArgumentError, "Invalid or non ascii-compatible encoding" + when :PM_STRING_QUERY_FALSE + false + when :PM_STRING_QUERY_TRUE + true + end + end + end + end +end |