module Fiddle::Importer

A DSL that provides the means to dynamically load libraries and build modules around them including calling extern functions within the C library that has been loaded.

Example¶ ↑

require 'fiddle'
require 'fiddle/import'

module LibSum
  extend Fiddle::Importer
  dlload './libsum.so'
  extern 'double sum(double*, int)'
  extern 'double split(double)'
end

Public Instance Methods

[](name) click to toggle source

Returns the function mapped to name, that was created by either Fiddle::Importer.extern or Fiddle::Importer.bind

# File ext/fiddle/lib/fiddle/import.rb, line 230
def [](name)
  @func_map[name]
end

bind(signature, *opts, &blk) click to toggle source

Creates a global method from the given C signature using the given opts as bind parameters with the given block.

# File ext/fiddle/lib/fiddle/import.rb, line 186
    def bind(signature, *opts, &blk)
      name, ctype, argtype = parse_signature(signature, @type_alias)
      h = parse_bind_options(opts)
      case h[:callback_type]
      when :bind, nil
        f = bind_function(name, ctype, argtype, h[:call_type], &blk)
      else
        raise(RuntimeError, "unknown callback type: #{h[:callback_type]}")
      end
      @func_map[name] = f
      #define_method(name){|*args,&block| f.call(*args,&block)}
      begin
        /^(.+?):(\d+)/ =~ caller.first
        file, line = $1, $2.to_i
      rescue
        file, line = __FILE__, __LINE__+3
      end
      module_eval(<<-EOS, file, line)
        def #{name}(*args,&block)
          @func_map['#{name}'].call(*args,&block)
        end
      EOS
      module_function(name)
      f
    end

bind_function(name, ctype, argtype, call_type = nil, &block) click to toggle source

Returns a new closure wrapper for the name function.

ctype is the return type of the function
argtype is an Array of arguments, passed to the callback function
call_type is the abi of the closure
block is passed to the callback

See Fiddle::Closure

# File ext/fiddle/lib/fiddle/import.rb, line 306
def bind_function(name, ctype, argtype, call_type = nil, &block)
  abi = CALL_TYPE_TO_ABI[call_type]
  closure = Class.new(Fiddle::Closure) {
    define_method(:call, block)
  }.new(ctype, argtype, abi)

  Function.new(closure, argtype, ctype, abi, name: name)
end

create_value(ty, val=nil) click to toggle source

Creates a class to wrap the C struct with the value ty

See also Fiddle::Importer.struct

# File ext/fiddle/lib/fiddle/import.rb, line 237
def create_value(ty, val=nil)
  s = struct([ty + " value"])
  ptr = s.malloc()
  if( val )
    ptr.value = val
  end
  return ptr
end

Also aliased as: value

dlload(*libs) click to toggle source

Creates an array of handlers for the given libs, can be an instance of Fiddle::Handle, Fiddle::Importer, or will create a new instance of Fiddle::Handle using Fiddle.dlopen

Raises a DLError if the library cannot be loaded.

See Fiddle.dlopen

# File ext/fiddle/lib/fiddle/import.rb, line 73
def dlload(*libs)
  handles = libs.collect{|lib|
    case lib
    when nil
      nil
    when Handle
      lib
    when Importer
      lib.handlers
    else
      begin
        Fiddle.dlopen(lib)
      rescue DLError
        raise(DLError, "can't load #{lib}")
      end
    end
  }.flatten()
  @handler = CompositeHandler.new(handles)
  @func_map = {}
  @type_alias = {}
end

extern(signature, *opts) click to toggle source

Creates a global method from the given C signature.

# File ext/fiddle/lib/fiddle/import.rb, line 162
    def extern(signature, *opts)
      symname, ctype, argtype = parse_signature(signature, @type_alias)
      opt = parse_bind_options(opts)
      f = import_function(symname, ctype, argtype, opt[:call_type])
      name = symname.gsub(/@.+/,'')
      @func_map[name] = f
      # define_method(name){|*args,&block| f.call(*args,&block)}
      begin
        /^(.+?):(\d+)/ =~ caller.first
        file, line = $1, $2.to_i
      rescue
        file, line = __FILE__, __LINE__+3
      end
      module_eval(<<-EOS, file, line)
        def #{name}(*args, &block)
          @func_map['#{name}'].call(*args,&block)
        end
      EOS
      module_function(name)
      f
    end

handler() click to toggle source

The Fiddle::CompositeHandler instance

Will raise an error if no handlers are open.

# File ext/fiddle/lib/fiddle/import.rb, line 259
def handler
  @handler or raise "call dlload before importing symbols and functions"
end

import_function(name, ctype, argtype, call_type = nil) click to toggle source

Returns a new Fiddle::Function instance at the memory address of the given name function.

Raises a DLError if the name doesn't exist.

argtype is an Array of arguments, passed to the name function.
ctype is the return type of the function
call_type is the ABI of the function

See also Fiddle:Function.new

See Fiddle::CompositeHandler.sym and Fiddle::Handler.sym

# File ext/fiddle/lib/fiddle/import.rb, line 289
def import_function(name, ctype, argtype, call_type = nil)
  addr = handler.sym(name)
  if( !addr )
    raise(DLError, "cannot find the function: #{name}()")
  end
  Function.new(addr, argtype, ctype, CALL_TYPE_TO_ABI[call_type],
               name: name)
end

import_symbol(name) click to toggle source

Returns a new Fiddle::Pointer instance at the memory address of the given name symbol.

Raises a DLError if the name doesn't exist.

See Fiddle::CompositeHandler.sym and Fiddle::Handle.sym

# File ext/fiddle/lib/fiddle/import.rb, line 269
def import_symbol(name)
  addr = handler.sym(name)
  if( !addr )
    raise(DLError, "cannot find the symbol: #{name}")
  end
  Pointer.new(addr)
end

import_value(ty, addr) click to toggle source

Returns a new instance of the C struct with the value ty at the addr address.

# File ext/fiddle/lib/fiddle/import.rb, line 249
def import_value(ty, addr)
  s = struct([ty + " value"])
  ptr = s.new(addr)
  return ptr
end

sizeof(ty) click to toggle source

Returns the sizeof ty, using Fiddle::Importer.parse_ctype to determine the C type and the appropriate Fiddle constant.

# File ext/fiddle/lib/fiddle/import.rb, line 102
def sizeof(ty)
  case ty
  when String
    ty = parse_ctype(ty, @type_alias).abs()
    case ty
    when TYPE_CHAR
      return SIZEOF_CHAR
    when TYPE_SHORT
      return SIZEOF_SHORT
    when TYPE_INT
      return SIZEOF_INT
    when TYPE_LONG
      return SIZEOF_LONG
    when TYPE_LONG_LONG
      return SIZEOF_LONG_LONG
    when TYPE_FLOAT
      return SIZEOF_FLOAT
    when TYPE_DOUBLE
      return SIZEOF_DOUBLE
    when TYPE_VOIDP
      return SIZEOF_VOIDP
    else
      raise(DLError, "unknown type: #{ty}")
    end
  when Class
    if( ty.instance_methods().include?(:to_ptr) )
      return ty.size()
    end
  end
  return Pointer[ty].size()
end

struct(signature) click to toggle source

Creates a class to wrap the C struct described by signature.

MyStruct = struct ['int i', 'char c']

# File ext/fiddle/lib/fiddle/import.rb, line 215
def struct(signature)
  tys, mems = parse_struct_signature(signature, @type_alias)
  Fiddle::CStructBuilder.create(CStruct, tys, mems)
end

typealias(alias_type, orig_type) click to toggle source

Sets the type alias for alias_type as orig_type

# File ext/fiddle/lib/fiddle/import.rb, line 96
def typealias(alias_type, orig_type)
  @type_alias[alias_type] = orig_type
end

union(signature) click to toggle source

Creates a class to wrap the C union described by signature.

MyUnion = union ['int i', 'char c']

# File ext/fiddle/lib/fiddle/import.rb, line 223
def union(signature)
  tys, mems = parse_struct_signature(signature, @type_alias)
  Fiddle::CStructBuilder.create(CUnion, tys, mems)
end

value(ty, val=nil)

Alias for: create_value

Private Instance Methods

parse_bind_options(opts) click to toggle source

# File ext/fiddle/lib/fiddle/import.rb, line 134
def parse_bind_options(opts)
  h = {}
  while( opt = opts.shift() )
    case opt
    when :stdcall, :cdecl
      h[:call_type] = opt
    when :carried, :temp, :temporal, :bind
      h[:callback_type] = opt
      h[:carrier] = opts.shift()
    else
      h[opt] = true
    end
  end
  h
end