Class: MetaHeader

Inherits:
Object
  • Object
show all
Defined in:
lib/metaheader.rb,
lib/metaheader/version.rb

Defined Under Namespace

Classes: Parser, Tag

Constant Summary collapse

REQUIRED = 
Object.new.freeze
OPTIONAL = 
Object.new.freeze
REGEX = 
/\A(?<prefix>.*?)
(?:@(?<key>\w+)|(?<key>[\w][\w\s]*?)\s*:)
(?:\s+(?<value>[^\n]+))?
\Z/x.freeze
VERSION = 
"1.0"

Instance Attribute Summary collapse

Class Method Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(input) ⇒ MetaHeader

Returns a new instance of MetaHeader.



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# File 'lib/metaheader.rb', line 36

def initialize(input)
  @strict = false
  @data = {}

  @last_key = nil
  @last_prefix = String.new

  input.each_line {|line|
    if line.strip.empty?
      break
    else
      self.<< line
    end
  }

  Parser.each {|klass|
    parser = klass.new self
    parser.parse input
  }
end

Instance Attribute Details

#strict ⇒ Object

Returns the value of attribute strict.



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# File 'lib/metaheader.rb', line 25

def strict
  @strict
end

Class Method Details

.from_file(file) ⇒ Object 



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# File 'lib/metaheader.rb', line 32

def self.from_file(file)
  self.new File.read(file)
end

Instance Method Details

#<<(line) ⇒ Object 



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# File 'lib/metaheader.rb', line 57

def <<(line)
  # multiline value must have the same prefix
  if @last_key && line.index(@last_prefix) == 0
    # remove the line prefix
    mline = line[@last_prefix.size..-1]
    stripped = mline.strip

    indent_level = mline.index stripped

    if indent_level > 0
      tag = @data[@last_key]

      if tag.value.is_a? String
        tag.value += "\n"
      else
        tag.value = String.new
      end

      tag.value += stripped

      return
    else
      @last_key = nil
    end
  end

  return unless match = REGEX.match(line)

  # single line
  @last_prefix = match[:prefix]
  @last_key = match[:key].downcase.gsub(/[^\w]/, '_').to_sym

  value = match[:value] || true
  @data[@last_key] = Tag.new match[:key].freeze, value
end

#[](key) ⇒ Object 



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# File 'lib/metaheader.rb', line 93

def [](key)
  tag = @data[key] and tag.value
end

#[]=(key, value) ⇒ Object 



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# File 'lib/metaheader.rb', line 97

def []=(key, value)
  @data[key] ||= Tag.new key
  @data[key].value = value
end

#empty? ⇒ Boolean

Returns:

  • (Boolean) 


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# File 'lib/metaheader.rb', line 106

def empty?
  @data.empty?
end

#inspect ⇒ Object 



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# File 'lib/metaheader.rb', line 114

def inspect
  to_h.inspect
end

#size ⇒ Object 



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# File 'lib/metaheader.rb', line 102

def size
  @data.size
end

#to_h ⇒ Object 



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# File 'lib/metaheader.rb', line 110

def to_h
  Hash[@data.map {|v| [v.first, v.last.value] }]
end

#validate(rules) ⇒ Object 



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# File 'lib/metaheader.rb', line 118

def validate(rules)
  errors = Array.new

  if @strict
    @data.each_key {|key|
      errors << 'unknown tag "%s"' % key unless rules.has_key? key
    }
  end

  rules.each_pair {|key, rule|
    if key_errors = validate_key(key, rule)
      errors.concat key_errors
    end
  }

  errors.empty? ? nil : errors
end

#validate_key(key, rules) ⇒ Object 



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# File 'lib/metaheader.rb', line 136

def validate_key(key, rules)
  rules = Array(rules)
  return if rules.empty?

  errors = Array.new

  unless @data.has_key? key
    if rules.include? OPTIONAL
      return nil
    else
      return ['missing tag "%s"' % key]
    end
  end

  tag = @data[key]
  value = tag.value
  value = String.new if value == true

  rules.each {|rule|
    case rule
    when REQUIRED, OPTIONAL
      # do nothing
    when Regexp
      unless rule.match value
        errors << 'invalid value for tag "%s"' % tag.name
      end
    when Proc
      if error = rule[value]
        errors << 'invalid value for tag "%s": %s' % [tag.name, error]
      end
    else
      raise ArgumentError
    end
  }

  errors.empty? ? nil : errors
end