Class: Veriform::Parser

Inherits:
Object
  • Object
show all
Defined in:
lib/veriform/parser.rb

Overview

Parses encoded Veriform messages, invoking callbacks in the given handler (i.e. this is a “push parser” which supports different backends)

Constant Summary collapse

MAX_LENGTH =

Default maximum length of a Veriform message. This is a conservative choice as Veriform’s main intended use is a credential format.

1024
MAX_DEPTH =

Default maximum depth (i.e. number of levels of child objects)

8

Instance Method Summary collapse

Constructor Details

#initialize(handler, max_length = MAX_LENGTH, max_depth = MAX_DEPTH) ⇒ Parser

Create a new message parser with the given parse event handler



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# File 'lib/veriform/parser.rb', line 15

def initialize(handler, max_length = MAX_LENGTH, max_depth = MAX_DEPTH)
  @handler = handler
  @max_length = max_length
  @max_depth = max_depth
  @remaining = []
end

Instance Method Details

#finish ⇒ Object

Finish parsing, returning the resulting object produced by the builder



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# File 'lib/veriform/parser.rb', line 47

def finish
  @handler.finish
end

#parse(msg) ⇒ Object

Parse the given Veriform message, invoking callbacks as necessary

Raises:



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# File 'lib/veriform/parser.rb', line 23

def parse(msg)
  raise OversizeMessageError, "length #{msg.length} exceeds max of #{@max_length}" if msg.length > @max_length
  raise EncodingError, "expected BINARY encoding, got #{msg.encoding}" unless msg.encoding == Encoding::BINARY
  @remaining << msg

  raise DepthError, "exceeded max depth of #{@max_depth}" if @remaining.size > @max_depth

  until @remaining.last.empty?
    id, wiretype = parse_field_prefix

    case wiretype
    when 0 then parse_uint64(id)
    when 2 then parse_message(id)
    when 3 then parse_binary(id)
    else raise ParseError, "unknown wiretype: #{wiretype.inspect}"
    end
  end

  @remaining.pop

  true
end