Class: Sequel::Postgres::PGArray::Parser

Inherits:
Object
  • Object
show all
Defined in:
lib/sequel/extensions/pg_array.rb

Overview

PostgreSQL array parser that handles all types of input.

This parser is very simple and unoptimized, but should still be O(n) where n is the length of the input string.

Instance Attribute Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(source, converter = nil) ⇒ Parser

Returns a new instance of Parser.



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# File 'lib/sequel/extensions/pg_array.rb', line 302

def initialize(source, converter=nil)
  @source = source
  @source_length = source.length
  @converter = converter 
  @pos = -1
  @entries = []
  @recorded = ""
  @dimension = 0
end

Instance Attribute Details

#pos ⇒ Object (readonly)

Returns the value of attribute pos.



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# File 'lib/sequel/extensions/pg_array.rb', line 296

def pos
  @pos
end

Instance Method Details

#new_entry(include_empty = false) ⇒ Object 



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# File 'lib/sequel/extensions/pg_array.rb', line 331

def new_entry(include_empty=false)
  if !@recorded.empty? || include_empty
    entry = @recorded
    if entry == NULL && !include_empty
      entry = nil
    elsif @converter
      entry = @converter.call(entry)
    end
    @entries.push(entry)
    @recorded = ""
  end
end

#next_char ⇒ Object 



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# File 'lib/sequel/extensions/pg_array.rb', line 314

def next_char
  @pos += 1
  if (c = @source[@pos..@pos]) == BACKSLASH
    @pos += 1
    [true, @source[@pos..@pos]]
  else
    [false, c]
  end
end

#parse(nested = false) ⇒ Object

Raises:



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# File 'lib/sequel/extensions/pg_array.rb', line 346

def parse(nested=false)
  # quote sets whether we are inside of a quoted string.
  quote = false
  until @pos >= @source_length
    escaped, char = next_char
    if char == OPEN_BRACE && !quote
      @dimension += 1
      if (@dimension > 1)
        # Multi-dimensional array encounter, use a subparser
        # to parse the next level down.
        subparser = self.class.new(@source[@pos..-1], @converter)
        @entries.push(subparser.parse(true))
        @pos += subparser.pos - 1
      end
    elsif char == CLOSE_BRACE && !quote
      @dimension -= 1
      if (@dimension == 0)
        new_entry
        # Exit early if inside a subparser, since the
        # text after parsing the current level should be
        # ignored as it is handled by the parent parser.
        return @entries if nested
      end
    elsif char == QUOTE && !escaped
      # If already inside the quoted string, this is the
      # ending quote, so add the entry.  Otherwise, this
      # is the opening quote, so set the quote flag.
      new_entry(true) if quote
      quote = !quote
    elsif char == COMMA && !quote
      # If not inside a string and a comma occurs, it indicates
      # the end of the entry, so add the entry.
      new_entry
    else
      # Add the character to the recorded character buffer.
      record(char)
    end
  end
  raise Sequel::Error, "array dimensions not balanced" unless @dimension == 0
  @entries
end

#record(c) ⇒ Object 



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# File 'lib/sequel/extensions/pg_array.rb', line 325

def record(c)
  @recorded << c
end