Class: Hash

Inherits:
Object show all
Defined in:
lib/strokedb/core_ext/hash.rb,
lib/strokedb/core_ext/blank.rb,
lib/strokedb/sync/diff/hash.rb,
lib/strokedb/util/serialization.rb

Overview

:nodoc:

Direct Known Subclasses

StrokeDB::LazyMappingHash

Instance Method Summary collapse

Instance Method Details

#_stroke_split_merge_result(result) ⇒ Object

In case of conflict, result is copied to result1,2 and nullified.



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# File 'lib/strokedb/sync/diff/hash.rb', line 182

def _stroke_split_merge_result(result)
  return [result.dup, result.dup, nil]
end

#except(*keys) ⇒ Object 



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# File 'lib/strokedb/core_ext/hash.rb', line 11

def except(*keys)
  reject { |key,| keys.include?(key.to_sym) or keys.include?(key.to_s) }
end

#reverse_merge(other_hash) ⇒ Object 



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# File 'lib/strokedb/core_ext/hash.rb', line 15

def reverse_merge(other_hash)
  other_hash.merge(self)
end

#reverse_merge!(other_hash) ⇒ Object 



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# File 'lib/strokedb/core_ext/hash.rb', line 19

def reverse_merge!(other_hash)
  replace(reverse_merge(other_hash))
end

#stringify_keys ⇒ Object 



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# File 'lib/strokedb/core_ext/hash.rb', line 4

def stringify_keys
  inject({}) do |options, (key, value)|
    options[key.to_s] = value
    options
  end
end

#stroke_diff(to) ⇒ Object 



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# File 'lib/strokedb/sync/diff/hash.rb', line 3

def stroke_diff(to)
  return super(to) unless to.is_a?(Hash)
  return nil if self == to
  
  all_keys = self.keys | to.keys
  
  deleted_slots  = []
  inserted_slots = {}
  diffed_slots   = {}
  
  all_keys.each do |k|
    unless to.key?(k)
      deleted_slots << k
    else
      unless self.key?(k)
        inserted_slots[k] = to[k] 
      else
        diff = self[k].stroke_diff(to[k]) 
        diffed_slots[k] = diff if diff
      end
    end
  end
  [deleted_slots, inserted_slots, diffed_slots]
end

#stroke_merge(patch1, patch2) ⇒ Object

Hash conflict may occur: 1) If key accures in conflicting groups 

(e.g. deleted v.s. inserted, deleted vs. diffed)

2) If slot diff yields conflict



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# File 'lib/strokedb/sync/diff/hash.rb', line 44

def stroke_merge(patch1, patch2)
  unless patch1 && patch2
    return _stroke_automerged(stroke_patch(patch1 || patch2))
  end
  
  del1, ins1, dif1 = patch1[0].dup, patch1[1].dup, patch1[2].dup
  del2, ins2, dif2 = patch2[0].dup, patch2[1].dup, patch2[2].dup
  
  # TEMPORARY: inconsistency check
  conflict_d1i2 = del1 & ins2.keys
  conflict_d2i1 = del2 & ins1.keys
  conflict_i1f2 = ins1.keys & dif2.keys
  conflict_i2f1 = ins2.keys & dif1.keys
  
  unless conflict_d1i2.empty? && conflict_d2i1.empty? && 
         conflict_i1f2.empty? && conflict_i2f1.empty? 
    raise "Fatal inconsistency on stroke_merge detected!"
  end
  
  overlapping_keys = ((del1 + ins1.keys + dif1.keys) & 
                      (del2 + ins2.keys + dif2.keys))
  # make hash for faster inclusion tests
  overlapping_keys_hash = overlapping_keys.inject({}) do |h, k|
    h[k] = 1; h
  end
  
  result  = self.dup
  
  # 1. Merge non-overlapping updates
  (del1 + del2 - overlapping_keys).each do |k|
    del1.delete(k)
    del2.delete(k)
    result.delete(k)
  end
  ins1.dup.each do |k, v|
    unless overlapping_keys_hash[k]
      result[k] = v 
      ins1.delete(k)
    end
  end
  ins2.dup.each do |k, v|
    unless overlapping_keys_hash[k]
      result[k] = v 
      ins2.delete(k)
    end
  end
  dif1.dup.each do |k, diff|
    unless overlapping_keys_hash[k]
      result[k] = stroke_patch(diff)
      dif1.delete(k)
    end
  end
  dif2.dup.each do |k, diff|
    unless overlapping_keys_hash[k]
      result[k] = stroke_patch(diff)
      dif2.delete(k)
    end
  end

  # 2. Resolve overlapping keys
  #
  # Overlapping key may be in such pairs:
  #
  #  [dif, dif] <- possible conflict
  #  [dif, ins] <- anomaly
  #  [ins, ins] <- possible conflict
  #  [del, ins] <- anomaly
  #  [del, dif] <- conflict
  #  [del, del] <- not a conflict
  #
  #  (and in reverse order as well)
  
  result1 = nil
  result2 = nil
  del1.each do |k|
    if ins2.key?(k)
      raise "Fatal inconsistency on stroke_merge detected: delete + insert"
    elsif dif2.key?(k) 
      # Conflict. Split result if not splitted.
      result1, result2, result = _stroke_split_merge_result(result) if result
      result1.delete(k)
      result2[k] = result2[k].stroke_patch(dif2[k])
    else # [del, del]
      if result
        result.delete(k)
      else
        result1.delete(k)
        result2.delete(k)
      end
    end
  end
  dif1.each do |k, diff|
    if ins2.key?(k)
      raise "Fatal inconsistency on stroke_merge detected: diff + insert"
    elsif dif2.key?(k) # possible conflict
      conflict, r1, r2 = self[k].stroke_merge(diff, dif2[k])
      if conflict
        result1, result2, result = _stroke_split_merge_result(result) if result
        result1[k] = r1
        result2[k] = r2
      else
        if result
          result[k] = r2
        else
          result1[k] = r2
          result2[k] = r2
        end
      end
    else # [dif, del] <- conflict
      # Conflict. Split result if not splitted.
      result1, result2, result = _stroke_split_merge_result(result) if result
      result1[k] = result1[k].stroke_patch(diff)
      result2.delete(k)
    end
  end
  ins1.each do |k, obj|
    if ins2.key?(k) # possible conflict
      if obj != ins2[k]
        result1, result2, result = _stroke_split_merge_result(result) if result
        result1[k] = obj
        result2[k] = ins2[k]
      else
        if result
          result[k] = obj
        else
          result1[k] = obj
          result2[k] = obj
        end
      end
    else # delete or diff
      raise "Fatal inconsistency on stroke_merge detected: insert + (delete|diff)"
    end
  end
  
  result ? _stroke_automerged(result) : _stroke_conflicted(result1, result2)
end

#stroke_patch(patch) ⇒ Object 



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# File 'lib/strokedb/sync/diff/hash.rb', line 28

def stroke_patch(patch)
  return self unless patch
  return patch[1] if patch[0] == PATCH_REPLACE
  res = self.dup
  deleted_slots, inserted_slots, diffed_slots = patch
  deleted_slots.each {|k| res.delete(k) }
  res.merge!(inserted_slots)
  diffed_slots.each {|k,v| res[k] = self[k].stroke_patch(v) }
  res
end

#to_raw ⇒ Object 



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# File 'lib/strokedb/util/serialization.rb', line 12

def to_raw
  raw_hash = {}
  map do |k,v|
    _k = k.respond_to?(:to_raw) ? k.to_raw : k
    _v = v.respond_to?(:to_raw) ? v.to_raw : v
    raw_hash[_k] = _v
  end
  raw_hash
end