Class: Safe::SafeHash

Inherits:
Object
  • Object
show all
Extended by:
Forwardable
Defined in:
lib/safestruct/safe_hash.rb

Class Method Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize ⇒ SafeHash

Returns a new instance of SafeHash.



88
89
90
91
 
# File 'lib/safestruct/safe_hash.rb', line 88

def initialize
  ## todo/check: if hash works if value is a (nested) hash
  @h = {}
end

Class Method Details

.build_class(klass_key, klass_value) ⇒ Object

note: need to create new class!! for every safe hash

make klass_key class and
     klass_value class  into class instance variables
that can get used by zero
  self.new returns a Hash.new/SafeHash.new like object



20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
 
# File 'lib/safestruct/safe_hash.rb', line 20

def self.build_class( klass_key, klass_value )
  ## note: care for now only about value type / class

  ## note: keep a class cache
  cache = @@cache ||= {}
  klass = cache[ klass_value ]
  if debug?
    puts "[debug] SafeHash - build_class klass_value:"
    pp klass_value
    pp klass_value.to_s    ## note: for "anonymous" class something like #<Class:>
  end

  if klass.nil?
    if debug?
      puts "[debug] SafeHash - build_class new class (no cache hit)"
    end

    klass = Class.new( SafeHash )

    klass.define_singleton_method( :klass_key ) do
      @klass_key ||= klass_key
    end
    klass.define_singleton_method( :klass_value ) do
      @klass_value ||= klass_value
    end

    ### was:  - NOT working for "anonymous" classes e.g. klass_value.to_s starting with #<Class:>
    # klass.class_eval( <<RUBY )
    #  def self.klass_key
    #    @klass_key   ||= #{klass_key}
    #  end
    #  def self.klass_value
    #    @klass_value ||= #{klass_value}
    #  end
# RUBY

    ## add to cache for later (re)use
    cache[ klass_value ] = klass

    ## note: also add a Constant to Safe for easy debugging and (re)use - will "auto"name class
    ##   note: use X for now for key class name
    class_name = "Hash_X"

    name = klass_value.name
    name = name.sub( /\bSafe::/, '' )   ## remove safe module from name if present
    name = name.gsub( '::', '' )        ## remove module separator if present
    class_name << "_#{name}"
    if debug?
      puts "[debug] SafeHash - class_name >#{class_name}<"
    end
    Safe.const_set( class_name, klass )
  else
    if debug?
      puts "[debug] SafeHash - build_class bingo!! (re)use cached class:"
      pp klass
    end
  end

  klass
end

.debug=(value) ⇒ Object 



8
 
# File 'lib/safestruct/safe_hash.rb', line 8

def self.debug=(value) @debug = value; end

.debug? ⇒ Boolean

Returns:

  • (Boolean) 


7
 
# File 'lib/safestruct/safe_hash.rb', line 7

def self.debug?()      @debug ||= false; end

.new_zero ⇒ Object 



82
 
# File 'lib/safestruct/safe_hash.rb', line 82

def self.new_zero()  new;  end

.zero ⇒ Object 



83
 
# File 'lib/safestruct/safe_hash.rb', line 83

def self.zero()      @zero ||= new_zero.freeze;  end

Instance Method Details

#==(other) ⇒ Object Also known as: eql? 



99
100
101
102
103
104
105
 
# File 'lib/safestruct/safe_hash.rb', line 99

def ==( other )
  if other.is_a?( self.class )                    ## note: must be same hash class
    @h == other.instance_variable_get( '@h' )    ## compare "wrapped" hash
  else
    false
  end
end

#[](key) ⇒ Object 



115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
 
# File 'lib/safestruct/safe_hash.rb', line 115

def [](key)
  item = @h[ key ]
  if item.nil?
    ## pp self.class.klass_value
    ## pp self.class.klass_value.zero

    #####
    # todo/check:
    #    add zero to hash on lookup (increases size/length)
    #    why? why not?

    if self.class.klass_value.respond_to?( :new_zero )
      ## note: use a dup(licated) unfrozen copy of the zero object
      ##    changes to the object MUST be possible (new "empty" modifable object expected)
      item = @h[ key ] = self.class.klass_value.new_zero
    else  # assume value semantics e.g. Integer, Bool, etc. zero values gets replaced
      ## puts "use value semantics"
      item = @h[ key ] = self.class.klass_value.zero
    end
  end
  item
end

#[]=(key, value) ⇒ Object 



111
112
113
 
# File 'lib/safestruct/safe_hash.rb', line 111

def []=(key, value)
  @h[key] = value
end

#freeze ⇒ Object 



93
94
95
96
97
 
# File 'lib/safestruct/safe_hash.rb', line 93

def freeze
  super
  @h.freeze  ## note: pass on freeze to "wrapped" hash
  self   # return reference to self
end

#zero? ⇒ Boolean

Returns:

  • (Boolean) 


85
 
# File 'lib/safestruct/safe_hash.rb', line 85

def zero?() self == self.class.zero; end