Class: Bijou::ErrorFormatter

Inherits:
Object
  • Object
show all
Defined in:
lib/bijou/errorformatter.rb

Overview

The error formatter is used at runtime to locate the origin of errors with respect to the source Bijou file. During processing, the text in a Bijou file is turned into Ruby code and cached as a separate file. It is the class contained in this file that is the runtime representation of a Bijou component. When a runtime error occurs, the exception refers to a location in the cached file. The ErrorFormatter class is used to find the location in the original Bijou file by referring to #line comments embedded in the cached file and back tracking from there.

Direct Known Subclasses

ErrorFormatterHTML, ErrorFormatterText

Instance Attribute Summary collapse

Class Method Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize ⇒ ErrorFormatter

Returns a new instance of ErrorFormatter.



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# File 'lib/bijou/errorformatter.rb', line 24

def initialize
  @title = ''
  @error = nil
  @errors = []
  @warnings = []
  @stack = []
  @adjacent_lines = 0

  # Context information
  @filename = ''
  @context_lines = []
  @error_line = 0
  @error_column = 0
  @context = nil
end

Instance Attribute Details

#error ⇒ Object

Returns the value of attribute error.



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# File 'lib/bijou/errorformatter.rb', line 22

def error
  @error
end

#errors ⇒ Object

Returns the value of attribute errors.



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# File 'lib/bijou/errorformatter.rb', line 22

def errors
  @errors
end

#stack ⇒ Object

Returns the value of attribute stack.



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# File 'lib/bijou/errorformatter.rb', line 22

def stack
  @stack
end

#title ⇒ Object

Returns the value of attribute title.



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# File 'lib/bijou/errorformatter.rb', line 22

def title
  @title
end

#warnings ⇒ Object

Returns the value of attribute warnings.



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# File 'lib/bijou/errorformatter.rb', line 22

def warnings
  @warnings
end

Class Method Details

.find_eval_line(error) ⇒ Object 



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# File 'lib/bijou/errorformatter.rb', line 186

def self.find_eval_line(error)
  line = 0

  #
  # This section requires a heuristic to find the most likely line that
  # is the origin of the error.
  #
  if error.to_s =~ /\(eval\)\:(\d+)\: parse error/
    return $1.to_i
  elsif error.to_s =~ /\(eval\)\:(\d+)\:/
    # Any eval line
    return $1.to_i
  end
  return 0
end

.format_error(format, adjacent_lines, context = nil) ⇒ Object 



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# File 'lib/bijou/errorformatter.rb', line 52

def self.format_error(format, adjacent_lines, context=nil)
  if format == :html
    formatter = ErrorFormatterHTML.new
  else
    formatter = ErrorFormatterText.new
  end

  @context = context

  result = ''

  error_line = 0
  error_column = 0

  error = $!

  if $!.kind_of?(Bijou::ParseError)
    formatter.title = $!.to_s

    filename = error.filename

    formatter.errors.replace(error.diagnostics.errors)
    formatter.warnings.replace(error.diagnostics.warnings)

    if error.diagnostics.errors
      # We use the first error as the origin.
      selected_error = error.diagnostics.errors[0]
      error_line = selected_error.line
      error_column = selected_error.column
    end
  else
    if $!.kind_of?(Bijou::EvalError)
      formatter.error = error.cause
      filename = error.filename
      cachename = error.cachename
    else
      formatter.error = $!

      # REVIEW: Are there any cases where the context would override
      # the EvalError location?
      if context
        filename = context.source_filename
        cachename = context.cache_filename
      elsif error.respond_to?('filename')
        filename = error.filename
        cachename = error.cachename
      end
    end

    # First, look for '(eval):#' in the error itself.
    eval_line = self.find_eval_line(formatter.error)
    if eval_line == 0
      # If not found, walk the stack.
      $@.each {|err|
        eval_line = self.find_eval_line(err)
        if eval_line > 0
          break
        end
      }
    end

    # Find the location in the original source using the line numbers 
    # in the cache.
    if eval_line > 0 && cachename
      error_line = self.get_source_file_line(cachename, eval_line)
    end
  end
    
  if filename && File.exists?(filename) && error_line > 0
    lines = self.get_file_context(filename, error_line, adjacent_lines)
    
    formatter.set_context(filename, lines, adjacent_lines,
                          error_line, error_column)
  else
    # TODO: Provide a default message using the best available info.
  end

  formatter.stack.replace($@)      

  result = formatter.format

  return result
end

.get_file_context(filename, line, adjacent_lines) ⇒ Object 



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# File 'lib/bijou/errorformatter.rb', line 136

def self.get_file_context(filename, line, adjacent_lines)
  file = File.new(filename, "r")

  min = line > adjacent_lines ? line - adjacent_lines : 1
  counter = 1;
  list = []

  while line = file.gets
    line.chomp!

    if counter >= min
      list.push({ 'number' => counter, 'text' => line })
      if counter >= min + 2 * adjacent_lines
        break
      end
    end

    counter += 1
  end

  file.close

  return list
end

.get_source_file_line(cachename, eval_line) ⇒ Object 



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# File 'lib/bijou/errorformatter.rb', line 161

def self.get_source_file_line(cachename, eval_line)
  file = File.new(cachename, "r")
  counter = 1
  most_recent_line = 0
  while line = file.gets
    line.chomp!
    
    if line =~ /\#line\s+(\d+)/
        most_recent_line = $1.to_i
        # Start back by one to account for the comment line.
        most_recent_line -= 1
    else
        most_recent_line += 1
    end

    if counter >= eval_line
      return most_recent_line
    end

    counter += 1
  end
  file.close
  return 0
end

Instance Method Details

#format ⇒ Object

Raises:

  • (StandardException) 


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# File 'lib/bijou/errorformatter.rb', line 48

def format
  raise StandardException, "Invalid error formatter"
end

#set_context(filename, lines, context, error_line, error_column) ⇒ Object 



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# File 'lib/bijou/errorformatter.rb', line 40

def set_context(filename, lines, context, error_line, error_column)
  @filename = filename
  @context_lines = lines
  @context = context
  @error_line = error_line
  @error_column = error_column
end