Class: Furnace::AVM2::Decompiler

Inherits:
Object
  • Object
show all
Includes:
Furnace::AST, ABC, Tokens
Defined in:
lib/furnace-avm2/source/decompiler.rb

Defined Under Namespace

Classes: ExpressionNotRecognized

Constant Summary collapse

StaticProperty = 
Matcher.new do
  [ either[:set_property, :init_property],
    [:find_property, capture(:property)],
    backref(:property),
    capture(:value)
  ]
end
KnownPushScopeMatcher = 
AST::Matcher.new do
  [:push_scope,
    either[
      [:get_local, capture(:get_local)],
      [:set_local, capture(:set_activation_local),
        [:new_activation]]
    ]
  ]
end
GetSlot = 
Matcher.new do
  [:get_slot,
    capture(:index),
    either[
      [:get_scope_object, capture(:scope_pos)],
      [:get_global_scope]
    ]
  ]
end
IMMEDIATE_TYPE_MAP = 
{
  :any       => '*',
  :integer   => 'int',
  :unsigned  => 'uint',
  :string    => 'String',
  :double    => 'Number',
  :object    => 'Object',
  :boolean   => 'Boolean',
  :true      => 'Boolean',
  :false     => 'Boolean',
}
XmlLiteralPreMatcher = 
Matcher.new do
  [:coerce, [:q, "XML"], any]
end
SetSlot = 
Matcher.new do
  [:set_slot,
    capture(:index),
    either[
      [:get_scope_object, capture(:scope_pos)],
      [:get_global_scope],
      [:push_scope,
        [:set_local, capture(:catch_local),
          [:new_catch, capture(:catch_id)]]]
    ],
    capture(:value)
  ]
end
ExceptionVariable = 
Matcher.new do
  [:exception_variable, capture(:variable)]
end
INPLACE_OPERATOR_MAP =

Arithmetics

{
  :inc_local   => :"++",
  :dec_local   => :"--",
}
PSEUDO_OPERATOR_MAP = 
{
  :increment   => [:"+", 1],
  :decrement   => [:"-", 1],
}
PrePostIncDecSlot = 
Matcher.new do
  [any,
    capture(:index),
    either[
      [:get_global_scope],
      [:get_scope_object, capture(:scope_pos)]
    ]
  ]
end
OPERATOR_MAP = 
{
  :and         => :"&&",
  :or          => :"||",

  :add         => :"+",
  :subtract    => :"-",
  :multiply    => :"*",
  :divide      => :"/",
  :modulo      => :"%",
  :multiply    => :"*",
  :negate      => :"-",

  :!           => :!,
  :>           => :>,
  :>=          => :>=,
  :<           => :<,
  :<=          => :<=,
  :==          => :==,
  :===         => :===,
  :!=          => :!=,
  :"!=="       => :"!==",

  :bit_and     => :"&",
  :bit_or      => :"|",
  :bit_xor     => :"^",
  :bit_not     => :"~",
  :lshift      => :"<<",
  :rshift      => :">>",
  :urshift     => :">>>",
}
This =

Properties and objects

Matcher.new do
  [:get_local, 0]
end
PropertyGlobal = 
Matcher.new do
  [any,
    either_multi[
      [
        [ either[:find_property, :find_property_strict],
              capture(:multiname)],
        backref(:multiname),
      ],
      [
        [:find_property_strict,
          [:m, [:set, any], any]],
        capture(:multiname)
      ],
      [
        either[
          [:get_scope_object, 0],
          [:get_global_scope]
        ],
        capture(:multiname)
      ],
    ],
    capture_rest(:arguments)]
end
CallThisGlobal =

See /src/java/macromedia/asc/semantics/CodeGenerator.java If this looks stupid to you, that’s because it IS stupid.

Matcher.new do
  [:get_global_scope]
end
CallThisLocal = 
Matcher.new do
  [ either[:get_scope_object, :get_local], 0 ]
end
XmlLiteralMatcher =

FFFUUUUUUUUUU~~~

Matcher.new do
  [:coerce, [:q, "XML"],
    [:construct,
      either[
        [:get_lex, [:q, "XML"]],
        [:get_property,
          [:find_property_strict, [:q, "XML"]], [:q, "XML"]]
      ],
      capture(:body),
    ]
  ]
end

Constants included from ABC

ABC::AST, ABC::CFG

Instance Method Summary collapse

Constructor Details

#initialize(body, options) ⇒ Decompiler

Returns a new instance of Decompiler.



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# File 'lib/furnace-avm2/source/decompiler.rb', line 15

def initialize(body, options)
  @body, @method, @options = body, body.method, options.dup
  @closure = @options.delete(:closure)
end

Instance Method Details

#decompile ⇒ Object 



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# File 'lib/furnace-avm2/source/decompiler.rb', line 20

def decompile
  begin
    @locals = Set.new([0]) + (1..@method.param_count).to_a
    @scopes = []
    @metascopes = []

    @catch_scopes = {}

    @closure_locals = Set.new

    @closure_slots  = {}
    @body.slot_traits.each do |trait|
      @closure_slots[trait.idx] = trait
    end

    @global_slots = @options[:global_slots] || {}

    stmt_block @body.code_to_nf,
      function: !@options[:global_code],
      closure:  @closure

  rescue Exception => e
    @failed = true

    comment = "'Ouch!' cried I, then died.\n" +
      "#{e.class}: #{e.message}\n" +
      "#{e.backtrace[0..5].map { |l| "    #{l}\n"}.join}" +
      "      ... et cetera\n"

    token(ScopeToken, [
      token(CommentToken, comment)
    ], function: !@options[:global_code],
       closure:  @closure)

  ensure
    if stat = @options[:stat]
      stat[:total] += 1

      if @failed
        stat[:failed]  += 1
      elsif @partial
        stat[:partial] += 1
      else
        stat[:success] += 1
      end
    end
  end
end

#decompose_static_initializer ⇒ Object 



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# File 'lib/furnace-avm2/source/decompiler.rb', line 77

def decompose_static_initializer
  properties = {}

  StaticProperty.find_all(@body.code_to_nf.children) do |match, captures|
    begin
      token = handle_expression(captures[:value])
    rescue ExpressionNotRecognized => e
      token = token(CommentToken, "Unrecognized static initializer:\n#{e.opcode.inspect}")
    end

    properties[captures[:property]] = token
  end

  properties
end

#expr_apply_type(opcode) ⇒ Object 



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# File 'lib/furnace-avm2/source/decompiler.rb', line 1014

def expr_apply_type(opcode)
  base, *args = opcode.children
  token(GenericTypeToken, [
    expr(base),
    token(GenericSpecializersToken,
      exprs(args))
  ])
end

#expr_arithmetic(opcode) ⇒ Object Also known as: expr_and, expr_or, expr_add, expr_subtract, expr_multiply, expr_divide, expr_modulo, expr_negate, expr_!, expr_>, expr_>=, expr_<, expr_<=, expr_==, expr_===, expr_!=, expr_!==, expr_bit_and, expr_bit_or, expr_bit_xor, expr_bit_not, expr_lshift, expr_rshift, expr_urshift 



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# File 'lib/furnace-avm2/source/decompiler.rb', line 757

def expr_arithmetic(opcode)
  if OPERATOR_MAP.include?(opcode.type)
    insides = parenthesize_each(exprs(opcode.children))

    if insides.count == 1
      token(UnaryOperatorToken, insides.first, OPERATOR_MAP[opcode.type])
    elsif insides.count == 2
      token(BinaryOperatorToken, insides, OPERATOR_MAP[opcode.type])
    else
      token(CommentToken, "Unexpected #{insides.count}-ary operator")
    end
  end
end

#expr_as_type_late(opcode) ⇒ Object

Types



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# File 'lib/furnace-avm2/source/decompiler.rb', line 998

def expr_as_type_late(opcode)
  token(AsToken, parenthesize_each(exprs(opcode.children)))
end

#expr_call(opcode) ⇒ Object 



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# File 'lib/furnace-avm2/source/decompiler.rb', line 968

def expr_call(opcode)
  subject, this, *args = opcode.children

  subject_token = token(AccessToken, [
    parenthesize(expr(subject)),
    token(PropertyNameToken, "call")
  ])

  if CallThisGlobal.match(this) || CallThisLocal.match(this)
    # FUCK YOU!
    token(CallToken, [
      subject_token,
      token(ArgumentsToken, [
        local_token(0),
        *exprs(args)
      ])
    ])
  else
    token(CallToken, [
      subject_token,
      token(ArgumentsToken, exprs([
        this,
        *args
      ]))
    ])
  end
end

#expr_call_property(opcode) ⇒ Object Also known as: expr_call_property_lex 



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# File 'lib/furnace-avm2/source/decompiler.rb', line 913

def expr_call_property(opcode)
  expr_do_property(opcode, CallToken, true)
end

#expr_call_super(opcode) ⇒ Object 



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# File 'lib/furnace-avm2/source/decompiler.rb', line 918

def expr_call_super(opcode)
  subject, multiname, *args = opcode.children
  if This.match subject
    token(CallToken, [
      get_name(token(SuperToken), multiname),
      token(ArgumentsToken, exprs(args))
    ])
  end
end

#expr_check_filter(node) ⇒ Object 



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# File 'lib/furnace-avm2/source/decompiler.rb', line 1100

def expr_check_filter(node)
  content, = node.children
  expr(content)
end

#expr_coerce(opcode) ⇒ Object 



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# File 'lib/furnace-avm2/source/decompiler.rb', line 1063

def expr_coerce(opcode)
  if captures = XmlLiteralMatcher.match(opcode)
    # Oh, shit...
    token(XmlLiteralToken,
      xml_expr(captures[:body]))
  else
    typename, subject, = opcode.children
    expr(subject)
  end
end

#expr_construct(opcode) ⇒ Object 



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# File 'lib/furnace-avm2/source/decompiler.rb', line 934

def expr_construct(opcode)
  type, *args = opcode.children
  token(NewToken, [
    parenthesize(expr(type)),
    token(ArgumentsToken, exprs(args))
  ])
end

#expr_construct_property(opcode) ⇒ Object

Object creation



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# File 'lib/furnace-avm2/source/decompiler.rb', line 930

def expr_construct_property(opcode)
  expr_do_property(opcode, NewToken, true)
end

#expr_construct_super(opcode) ⇒ Object 



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# File 'lib/furnace-avm2/source/decompiler.rb', line 942

def expr_construct_super(opcode)
  subject, *args = opcode.children
  if This.match subject
    token(CallToken, [
      token(SuperToken),
      token(ArgumentsToken, exprs(args))
    ])
  end
end

#expr_convert(opcode) ⇒ Object 



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# File 'lib/furnace-avm2/source/decompiler.rb', line 1027

def expr_convert(opcode)
  type, subject = opcode.children
  token(CallToken, [
    token(ImmediateTypenameToken, IMMEDIATE_TYPE_MAP[type]),
    token(ArgumentsToken, [
      expr(subject)
    ])
  ])
end

#expr_delete_property(opcode) ⇒ Object 



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# File 'lib/furnace-avm2/source/decompiler.rb', line 909

def expr_delete_property(opcode)
  expr_do_property(opcode, DeleteToken, false)
end

#expr_do_property(opcode, klass, has_args) ⇒ Object 



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# File 'lib/furnace-avm2/source/decompiler.rb', line 894

def expr_do_property(opcode, klass, has_args)
  if captures = PropertyGlobal.match(opcode)
    token(klass, [
      get_name(nil, captures[:multiname]),
      (token(ArgumentsToken, exprs(captures[:arguments])) if has_args)
    ])
  else
    subject, multiname, *args = opcode.children
    token(klass, [
      get_name(expr(subject), multiname),
      (token(ArgumentsToken, exprs(args)) if has_args)
    ])
  end
end

#expr_get_lex(opcode) ⇒ Object 



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# File 'lib/furnace-avm2/source/decompiler.rb', line 833

def expr_get_lex(opcode)
  multiname, = opcode.children
  get_name(nil, multiname)
end

#expr_get_local(opcode) ⇒ Object 



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# File 'lib/furnace-avm2/source/decompiler.rb', line 436

def expr_get_local(opcode)
  index, = opcode.children
  local_token(index)
end

#expr_get_property(opcode) ⇒ Object 



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# File 'lib/furnace-avm2/source/decompiler.rb', line 838

def expr_get_property(opcode)
  if captures = PropertyGlobal.match(opcode)
    get_name(nil, captures[:multiname])
  else
    subject, multiname, = opcode.children
    get_name(expr(subject), multiname)
  end
end

#expr_get_slot(opcode) ⇒ Object 



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# File 'lib/furnace-avm2/source/decompiler.rb', line 451

def expr_get_slot(opcode)
  if captures = GetSlot.match(opcode)
    scope = @scopes[captures[:scope_pos] || 0]

    if scope.is_a? Hash
      # treat as an inline scope, probably from an eh
      if scope[captures[:index]]
        var = scope[captures[:index]]
        token(VariableNameToken, var.metadata[:origin].name)
      end
    elsif @closure_slots && scope == :activation
      # treat as a local variable
      slot = @closure_slots[captures[:index]]
      token(VariableNameToken, slot.name.name)
    elsif scope == :this
      # treat as a global property
      if slot = @global_slots[captures[:index]]
        get_name(nil, slot.name.to_astlet)
      else
        token(PropertyNameToken,
          "$__GLOBAL_#{captures[:index]}")
      end
    end
  end
end

#expr_get_super(opcode) ⇒ Object 



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# File 'lib/furnace-avm2/source/decompiler.rb', line 847

def expr_get_super(opcode)
  subject, multiname, = opcode.children

  stmt = get_name(token(SuperToken), multiname)

  unless This.match subject
    stmt = token(SupplementaryCommentToken,
      "subject != this: #{subject.inspect}",
      [ stmt ])
  end

  stmt
end

#expr_imm(opcode) ⇒ Object Also known as: expr_integer, expr_double, expr_null, expr_undefined, expr_true, expr_false

Immediates



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# File 'lib/furnace-avm2/source/decompiler.rb', line 376

def expr_imm(opcode)
  case opcode.type
  when :integer, :double
    token(ImmediateToken, *opcode.children)
  when :null, :undefined, :true, :false
    token(ImmediateToken, opcode.type)
  end
end

#expr_in(opcode) ⇒ Object 



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# File 'lib/furnace-avm2/source/decompiler.rb', line 799

def expr_in(opcode)
  token(InToken, parenthesize_each(exprs(opcode.children)))
end

#expr_inplace_arithmetic(opcode) ⇒ Object Also known as: expr_inc_local, expr_dec_local 



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# File 'lib/furnace-avm2/source/decompiler.rb', line 642

def expr_inplace_arithmetic(opcode)
  index, = opcode.children

  token(UnaryPostOperatorToken,
    local_token(index),
    INPLACE_OPERATOR_MAP[opcode.type])
end

#expr_instance_of(opcode) ⇒ Object 



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# File 'lib/furnace-avm2/source/decompiler.rb', line 1006

def expr_instance_of(opcode)
  token(InstanceOfToken, parenthesize_each(exprs(opcode.children)))
end

#expr_is_type_late(opcode) ⇒ Object 



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# File 'lib/furnace-avm2/source/decompiler.rb', line 1002

def expr_is_type_late(opcode)
  token(IsToken, parenthesize_each(exprs(opcode.children)))
end

#expr_nan(opcode) ⇒ Object 



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# File 'lib/furnace-avm2/source/decompiler.rb', line 396

def expr_nan(opcode)
  token(ImmediateToken, "NaN")
end

#expr_new_array(opcode) ⇒ Object 



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# File 'lib/furnace-avm2/source/decompiler.rb', line 400

def expr_new_array(opcode)
  token(ArrayToken, exprs(opcode.children))
end

#expr_new_class(opcode) ⇒ Object 



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# File 'lib/furnace-avm2/source/decompiler.rb', line 1023

def expr_new_class(opcode)
  throw :skip
end

#expr_new_function(opcode) ⇒ Object

Closures



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# File 'lib/furnace-avm2/source/decompiler.rb', line 1039

def expr_new_function(opcode)
  index, = opcode.children
  body = @method.root.method_body_at(index)

  token(ClosureToken,
    body)
end

#expr_new_object(opcode) ⇒ Object 



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# File 'lib/furnace-avm2/source/decompiler.rb', line 404

def expr_new_object(opcode)
  token(ObjectToken, opcode.children.
    each_slice(2).map do |key, value|
      token(ObjectPairToken, [
        expr(key),
        expr(value)
      ])
    end)
end

#expr_prepost_incdec_local(opcode) ⇒ Object Also known as: expr_post_increment_local, expr_post_decrement_local, expr_pre_increment_local, expr_pre_decrement_local 



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# File 'lib/furnace-avm2/source/decompiler.rb', line 672

def expr_prepost_incdec_local(opcode)
  index, = opcode.children
  lvar = local_token(index)

  if opcode.type == :post_increment_local
    token(UnaryPostOperatorToken, lvar, "++")
  elsif opcode.type == :post_decrement_local
    token(UnaryPostOperatorToken, lvar, "--")
  elsif opcode.type == :pre_increment_local
    token(UnaryOperatorToken, lvar, "++")
  elsif opcode.type == :pre_decrement_local
    token(UnaryOperatorToken, lvar, "--")
  end
end

#expr_prepost_incdec_slot(opcode) ⇒ Object Also known as: expr_post_increment_slot, expr_post_decrement_slot, expr_pre_increment_slot, expr_pre_decrement_slot 



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# File 'lib/furnace-avm2/source/decompiler.rb', line 701

def expr_prepost_incdec_slot(opcode)
  if captures = PrePostIncDecSlot.match(opcode)
    scope = @scopes[captures[:scope_pos] || 0]

    if @closure_slots && scope == :activation
      slot_trait = @closure_slots[captures[:index]]
      slot = token(VariableNameToken, slot_trait.name.name)

      if opcode.type == :post_increment_slot
        token(UnaryPostOperatorToken, slot, "++")
      elsif opcode.type == :post_decrement_slot
        token(UnaryPostOperatorToken, slot, "--")
      elsif opcode.type == :pre_increment_slot
        token(UnaryOperatorToken, slot, "++")
      elsif opcode.type == :pre_decrement_slot
        token(UnaryOperatorToken, slot, "--")
      end
    end
  end
end

#expr_pseudo_arithmetic(opcode) ⇒ Object Also known as: expr_increment, expr_decrement 



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# File 'lib/furnace-avm2/source/decompiler.rb', line 658

def expr_pseudo_arithmetic(opcode)
  inside = expr(*opcode.children)
  inside = token(ParenthesesToken, [inside]) if inside.complex?

  operator, other_value = PSEUDO_OPERATOR_MAP[opcode.type]
  token(BinaryOperatorToken, [
    inside,
    token(ImmediateToken, other_value)
  ], operator)
end

#expr_set_local(opcode, toplevel = false) ⇒ Object 



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# File 'lib/furnace-avm2/source/decompiler.rb', line 536

def expr_set_local(opcode, toplevel=false)
  index, value = opcode.children
  if IMMEDIATE_TYPE_MAP.include?(value.type)
    type = token(TypeToken, [
      token(ImmediateTypenameToken, IMMEDIATE_TYPE_MAP[value.type])
    ])
  elsif XmlLiteralPreMatcher.match value
    # XML literals work through expr_coerce
    type  = type_token(value.children.first)
    value = value
  elsif value.type == :coerce || value.type == :convert
    # Don't emit spurious coercion; typed variables already
    # imply it
    type  = type_token(value.children.first)
    value = value.children.last
  end

  expr_set_var(local_token(index), value, type, !@locals.include?(index), toplevel)
ensure
  @locals.add index if index
end

#expr_set_local_toplevel(opcode) ⇒ Object 



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# File 'lib/furnace-avm2/source/decompiler.rb', line 558

def expr_set_local_toplevel(opcode)
  expr_set_local(opcode, true)
end

#expr_set_property(opcode) ⇒ Object Also known as: expr_init_property 



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# File 'lib/furnace-avm2/source/decompiler.rb', line 861

def expr_set_property(opcode)
  if captures = PropertyGlobal.match(opcode)
    token(AssignmentToken, [
      get_name(nil, captures[:multiname]),
      parenthesize(expr(*captures[:arguments]))
    ])
  else
    subject, multiname, value, = opcode.children
    token(AssignmentToken, [
      get_name(expr(subject), multiname),
      parenthesize(expr(value))
    ])
  end
end

#expr_set_slot(opcode, toplevel = false) ⇒ Object 



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# File 'lib/furnace-avm2/source/decompiler.rb', line 580

def expr_set_slot(opcode, toplevel=false)
  if captures = SetSlot.match(opcode)
    scope = @scopes[captures[:scope_pos] || 0]

    if captures[:catch_id]
      stmt = nil

      unless ExceptionVariable.match captures[:value], captures
        stmt = token(SupplementaryCommentToken,
          "Non-matching catch_id and catch id", [])
      end

      scope = {
        captures[:index] => captures[:variable]
      }

      @catch_scopes[captures[:catch_local]] = scope
      @scopes << scope

      throw :skip unless stmt
      stmt
    elsif @closure_slots && scope == :activation
      # treat as a local variable
      index, value = captures.values_at(:index, :value)
      slot = @closure_slots[index]

      type = type_token(slot.type.to_astlet) if slot.type
      expr = expr_set_var(token(VariableNameToken, slot.name.name),
            value, type,
            !@closure_locals.include?(index), toplevel)
      @closure_locals.add index

      expr
    elsif scope == :this
      # treat as a global property
      index, value = captures.values_at(:index, :value)

      if slot = @global_slots[index]
        name = get_name(nil, slot.name.to_astlet)
      else
        name = token(PropertyNameToken, "$__GLOBAL_#{index}")
      end

      token(AssignmentToken, [
        name,
        parenthesize(expr(value))
      ])
    end
  end
end

#expr_set_slot_toplevel(opcode) ⇒ Object 



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# File 'lib/furnace-avm2/source/decompiler.rb', line 631

def expr_set_slot_toplevel(opcode)
  expr_set_slot(opcode, true)
end

#expr_set_super(opcode) ⇒ Object 



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# File 'lib/furnace-avm2/source/decompiler.rb', line 877

def expr_set_super(opcode)
  subject, multiname, value = opcode.children

  stmt = token(AssignmentToken, [
    get_name(token(SuperToken), multiname),
    parenthesize(expr(value))
  ])

  unless This.match subject
    stmt = token(SupplementaryCommentToken,
      "subject != this: #{subject.inspect}",
      [ stmt ])
  end

  stmt
end

#expr_set_var(var, value, type, declare, toplevel) ⇒ Object 



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# File 'lib/furnace-avm2/source/decompiler.rb', line 505

def expr_set_var(var, value, type, declare, toplevel)
  if declare
    declaration =
      token(LocalVariableToken, [
        var,
        type
      ])
  end

  if declare && toplevel
    declaration.children <<
      token(InitializationToken, [
        expr(value)
      ])

    declaration
  else
    if declare
      @collected_vars <<
        token(StatementToken, [
          declaration
        ])
    end

    token(AssignmentToken, [
      var,
      parenthesize(expr(value))
    ])
  end
end

#expr_string(opcode) ⇒ Object 



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# File 'lib/furnace-avm2/source/decompiler.rb', line 391

def expr_string(opcode)
  string, = opcode.children
  token(ImmediateToken, string.inspect)
end

#expr_ternary(opcode) ⇒ Object

Control flow



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# File 'lib/furnace-avm2/source/decompiler.rb', line 954

def expr_ternary(opcode)
  token(TernaryOperatorToken, parenthesize_each(exprs(opcode.children)))
end

#expr_type_of(opcode) ⇒ Object 



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# File 'lib/furnace-avm2/source/decompiler.rb', line 1010

def expr_type_of(opcode)
  token(TypeOfToken, exprs(opcode.children))
end

#expression(opcode, toplevel = false) ⇒ Object Also known as: expr 



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# File 'lib/furnace-avm2/source/decompiler.rb', line 350

def expression(opcode, toplevel=false)
  if toplevel
    handler = :"expr_#{opcode.type}_toplevel"
    if respond_to?(handler) && node = send(handler, opcode)
      return node
    end
  end

  handler = :"expr_#{opcode.type}"
  if respond_to?(handler) && node = send(handler, opcode)
    node
  else
    raise ExpressionNotRecognized.new(nil, opcode)
  end
end

#expressions(opcodes) ⇒ Object Also known as: exprs 



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# File 'lib/furnace-avm2/source/decompiler.rb', line 367

def expressions(opcodes)
  opcodes.map do |opcode|
    expression opcode
  end
end

#handle_expression(opcode) ⇒ Object

Expressions



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# File 'lib/furnace-avm2/source/decompiler.rb', line 344

def handle_expression(opcode)
  expression(opcode, true)
rescue ExpressionNotRecognized => e
  raise ExpressionNotRecognized.new(opcode, e.opcode)
end

#local_token(index) ⇒ Object

Locals



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# File 'lib/furnace-avm2/source/decompiler.rb', line 416

def local_token(index)
  if index < 0
    token(VariableNameToken, "sp#{-index}")
  elsif index == 0
    if @options[:static]
      token(VariableNameToken, @options[:instance].name.name)
    else
      token(ThisToken)
    end
  elsif index <= @method.param_count
    if @method.has_param_names?
      token(VariableNameToken, @method.param_names[index - 1])
    else
      token(VariableNameToken, "param#{index - 1}")
    end
  else
    token(VariableNameToken, "local#{index - @method.param_count - 1}")
  end
end

#stmt_begin(opcode, nodes) ⇒ Object 



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# File 'lib/furnace-avm2/source/decompiler.rb', line 137

def stmt_begin(opcode, nodes)
  nodes << stmt_block(opcode)
end

#stmt_block(block, options = {}) ⇒ Object

Statements



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# File 'lib/furnace-avm2/source/decompiler.rb', line 95

def stmt_block(block, options={})
  nodes = []
  last_index = 0

  block.children.each_with_index do |opcode, index|
    last_index = index

    if respond_to?(:"stmt_#{opcode.type}")
      send :"stmt_#{opcode.type}", opcode, nodes
    else
      catch(:skip) do
        @collected_vars = []
        stmt = token(StatementToken, [
          handle_expression(opcode)
        ])

        nodes.concat @collected_vars
        nodes.push stmt
      end
    end
  end

rescue ExpressionNotRecognized => e
  @partial = true

  comment = "Well, this is embarassing.\n\n" +
    "Expression recognizer failed at:\n" +
    "#{e.opcode.inspect}\n"

  comment << "\nRest of the code in this block:\n"
  block.children[last_index..-1].each do |opcode|
    comment << "#{opcode.inspect}\n"
  end

  nodes << CommentToken.new(@body, comment, @options)

ensure
  if $!.nil? || $!.is_a?(ExpressionNotRecognized)
    return token(ScopeToken, nodes, options)
  end
end

#stmt_break(opcode, nodes) ⇒ Object 



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# File 'lib/furnace-avm2/source/decompiler.rb', line 213

def stmt_break(opcode, nodes)
  label, = opcode.children
  nodes << token(BreakToken, [
    (token(LabelNameToken, label) if label)
  ])
end

#stmt_case(opcode, nodes) ⇒ Object 



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# File 'lib/furnace-avm2/source/decompiler.rb', line 282

def stmt_case(opcode, nodes)
  value, = opcode.children
  nodes << token(CaseToken, handle_expression(value))
end

#stmt_continue(opcode, nodes) ⇒ Object 



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# File 'lib/furnace-avm2/source/decompiler.rb', line 220

def stmt_continue(opcode, nodes)
  label, = opcode.children
  nodes << token(ContinueToken, [
    (token(LabelNameToken, label) if label)
  ])
end

#stmt_default(opcode, nodes) ⇒ Object 



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# File 'lib/furnace-avm2/source/decompiler.rb', line 278

def stmt_default(opcode, nodes)
  nodes << token(CaseToken, nil)
end

#stmt_do_while(opcode, nodes) ⇒ Object 



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# File 'lib/furnace-avm2/source/decompiler.rb', line 175

def stmt_do_while(opcode, nodes)
  condition, body = opcode.children

  nodes << token(DoWhileToken,
    stmt_block(body, continuation: true),
    handle_expression(condition))
end

#stmt_for(opcode, nodes) ⇒ Object Also known as: stmt_for_in, stmt_for_each_in 



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# File 'lib/furnace-avm2/source/decompiler.rb', line 183

def stmt_for(opcode, nodes)
  value_reg, value_type, object_reg, body = opcode.children

  @locals.add(value_reg)

  if opcode.type == :for_in
    klass = ForToken
  elsif opcode.type == :for_each_in
    klass = ForEachToken
  end

  if @activation_local
    name = token(VariableNameToken, @closure_slots[value_reg].name.name)
  else
    name = local_token(value_reg)
  end

  nodes << token(klass,
    token(InToken, [
      token(LocalVariableToken, [
        name,
        type_token(value_type)
      ]),
      local_token(object_reg),
    ]),
    stmt_block(body))
end

#stmt_if(opcode, nodes) ⇒ Object 



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# File 'lib/furnace-avm2/source/decompiler.rb', line 141

def stmt_if(opcode, nodes)
  condition, if_true, if_false = opcode.children

  nodes << token(IfToken, handle_expression(condition),
    stmt_block(if_true, continuation: !if_false.nil?))

  if if_false
    first_child = if_false.children.first
    if if_false.children.count == 1 &&
          first_child.type == :if
      nodes << token(ElseToken,
        nil)
      stmt_if(first_child, nodes)
    else
      nodes << token(ElseToken,
        stmt_block(if_false))
    end
  end
end

#stmt_label(opcode, nodes) ⇒ Object 



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# File 'lib/furnace-avm2/source/decompiler.rb', line 161

def stmt_label(opcode, nodes)
  name, = opcode.children

  nodes << token(LabelDeclarationToken, name)
end

#stmt_pop_scope(opcode, nodes) ⇒ Object 



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# File 'lib/furnace-avm2/source/decompiler.rb', line 332

def stmt_pop_scope(opcode, nodes)
  if @options[:global_code]
    @scopes.pop
  elsif @scopes.any?
    @scopes.pop
  else
    raise "popscope with empty stack"
  end
end

#stmt_push_scope(opcode, nodes) ⇒ Object 



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# File 'lib/furnace-avm2/source/decompiler.rb', line 306

def stmt_push_scope(opcode, nodes)
  if @options[:global_code]
    @scopes.push opcode.children.first
  elsif captures = KnownPushScopeMatcher.match(opcode)
    if captures[:get_local] == 0
      @scopes << :this
    elsif !@activation_local.nil? &&
        captures[:get_local] == @activation_local
      @scopes << :activation
    elsif @catch_scopes.include? captures[:get_local]
      @scopes << @catch_scopes[captures[:get_local]]
    elsif captures[:set_activation_local]
      if @activation_local
        raise "more than one activation per function is not supported"
      end

      @scopes << :activation
      @activation_local = captures[:set_activation_local]
    else
      raise "abnormal matched pushscope in nonglobal code: #{captures.inspect}"
    end
  else
    raise "abnormal pushscope in nonglobal code"
  end
end

#stmt_return(opcode, nodes) ⇒ Object Also known as: stmt_return_value, stmt_return_void 



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# File 'lib/furnace-avm2/source/decompiler.rb', line 231

def stmt_return(opcode, nodes)
  nodes << token(ReturnToken, exprs(opcode.children))
end

#stmt_switch(opcode, nodes) ⇒ Object 



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# File 'lib/furnace-avm2/source/decompiler.rb', line 270

def stmt_switch(opcode, nodes)
  condition, body = opcode.children

  nodes << token(SwitchToken,
    handle_expression(condition),
    stmt_block(body))
end

#stmt_throw(opcode, nodes) ⇒ Object 



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# File 'lib/furnace-avm2/source/decompiler.rb', line 227

def stmt_throw(opcode, nodes)
  nodes << token(ThrowToken, exprs(opcode.children))
end

#stmt_try(opcode, nodes) ⇒ Object 



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# File 'lib/furnace-avm2/source/decompiler.rb', line 237

def stmt_try(opcode, nodes)
  body, *handlers = opcode.children

  nodes << token(TryToken, [
    stmt_block(body, continuation: true),
  ])

  handlers.each_with_index do |handler, index|
    block = within_meta_scope do
      stmt_block(handler.children.last, continuation: index < handlers.size - 1)
    end

    if handler.type == :catch
      type, variable, = handler.children

      if type
        filter_node = token(CatchFilterToken, [
          token(MultinameToken, variable.metadata[:origin]),
          token(MultinameToken, type.metadata[:origin])
        ])
      else
        filter_node = token(MultinameToken, variable.metadata[:origin])
      end

      nodes << token(CatchToken, filter_node, block)
    elsif handler.type == :finally
      nodes << token(FinallyToken, block)
    else
      raise "unknown handler type #{handler.type}"
    end
  end
end

#stmt_while(opcode, nodes) ⇒ Object 



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# File 'lib/furnace-avm2/source/decompiler.rb', line 167

def stmt_while(opcode, nodes)
  condition, body = opcode.children

  nodes << token(WhileToken,
    handle_expression(condition),
    stmt_block(body))
end

#type_token(type) ⇒ Object 



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# File 'lib/furnace-avm2/source/decompiler.rb', line 489

def type_token(type)
  if IMMEDIATE_TYPE_MAP.include?(type)
    token(TypeToken, [
      token(ImmediateTypenameToken, IMMEDIATE_TYPE_MAP[type])
    ])
  else
    token(TypeToken, [
      token(MultinameToken, type.metadata[:origin])
    ])
  end
end

#within_meta_scope ⇒ Object 



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# File 'lib/furnace-avm2/source/decompiler.rb', line 287

def within_meta_scope
  @metascopes.push @scopes
  @scopes = []

  yield
ensure
  @scopes = @metascopes.pop
end

#xml_add(node) ⇒ Object 



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# File 'lib/furnace-avm2/source/decompiler.rb', line 1086

def xml_add(node)
  node.children.map do |child|
    xml_expr child
  end.join
end

#xml_esc_xattr(node) ⇒ Object 



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# File 'lib/furnace-avm2/source/decompiler.rb', line 1092

def xml_esc_xattr(node)
  xml_expr(node.children.first)
end

#xml_esc_xelem(node) ⇒ Object 



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# File 'lib/furnace-avm2/source/decompiler.rb', line 1096

def xml_esc_xelem(node)
  xml_expr(node.children.first)
end

#xml_expr(node) ⇒ Object 



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# File 'lib/furnace-avm2/source/decompiler.rb', line 1074

def xml_expr(node)
  if respond_to?(:"xml_#{node.type}")
    send :"xml_#{node.type}", node
  else
    "{#{expr(node).to_text}}"
  end
end

#xml_string(node) ⇒ Object 



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# File 'lib/furnace-avm2/source/decompiler.rb', line 1082

def xml_string(node)
  node.children.first
end