Module: LineCache

Defined in:
lib/linecache.rb

Overview

module LineCache

Module caching lines of a file

Defined Under Namespace

Classes: LineCacheInfo

Constant Summary collapse

@@file_cache =

The file cache. The key is a name as would be given by Ruby for __FILE__. The value is a LineCacheInfo object.

{}
@@file2file_remap =

Maps a string filename (a String) to a key in @@file_cache (a String).

One important use of @@file2file_remap is mapping the a full path of a file into the name stored in @@file_cache or given by Ruby’s __FILE__. Applications such as those that get input from users, may want canonicalize a file name before looking it up. This map gives a way to do that.

Another related use is when a template system is used. Here we’ll probably want to remap not only the file name but also line ranges. Will probably use this for that, but I’m not sure.

{}
@@file2file_remap_lines = 
{}

Class Method Summary collapse

Class Method Details

.cache(filename, reload_on_change = false) ⇒ Object

Cache filename if it’s not already cached. Return the expanded filename for it in the cache or nil if we can’t find the file.



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# File 'lib/linecache.rb', line 142

def cache(filename, reload_on_change=false)
  if @@file_cache.member?(filename)
    checkcache(filename) if reload_on_change
  else
    update_cache(filename, true)
  end
  if @@file_cache.member?(filename)
    @@file_cache[filename].path
  else
    nil
  end
end

.cached?(filename) ⇒ Boolean

Return true if filename is cached

Returns:

  • (Boolean) 


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# File 'lib/linecache.rb', line 157

def cached?(filename)
  @@file_cache.member?(unmap_file(filename))
end

.cached_files ⇒ Object

Return an array of cached file names



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# File 'lib/linecache.rb', line 100

def cached_files()
  @@file_cache.keys
end

.cached_script?(filename) ⇒ Boolean

Returns:

  • (Boolean) 


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# File 'lib/linecache.rb', line 162

def cached_script?(filename)
  SCRIPT_LINES__.member?(unmap_file(filename))
end

.checkcache(filename = nil, use_script_lines = false) ⇒ Object

Discard cache entries that are out of date. If filename is nil all entries in the file cache @@file_cache are checked. If we don’t have stat information about a file which can happen if the file was read from __SCRIPT_LINES but no corresponding file is found, it will be kept. Return a list of invalidated filenames. nil is returned if a filename was given but not found cached.



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# File 'lib/linecache.rb', line 111

def checkcache(filename=nil, use_script_lines=false)
  
  if !filename
    filenames = @@file_cache.keys()
  elsif @@file_cache.member?(filename)
    filenames = [filename]
  else
    return nil
  end

  result = []
  for filename in filenames
    next unless @@file_cache.member?(filename)
    path = @@file_cache[filename].path
    if File.exist?(path)
      cache_info = @@file_cache[filename]
      stat = File.stat(path)
      if stat && 
          (cache_info.size != stat.size or cache_info.mtime != stat.mtime)
        result << filename
        update_cache(filename, use_script_lines)
      end
    end
  end
  return result
end

.clear_file_cache ⇒ Object

Clear the file cache entirely.



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# File 'lib/linecache.rb', line 92

def clear_file_cache()
  @@file_cache = {}
  @@file2file_remap = {}
  @@file2file_remap_lines = {}
end

.empty?(filename) ⇒ Boolean

Returns:

  • (Boolean) 


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# File 'lib/linecache.rb', line 167

def empty?(filename)
  filename=unmap_file(filename)
  @@file_cache[filename].lines.empty?
end

.getline(filename, line_number, reload_on_change = true) ⇒ Object

Get line line_number from file named filename. Return nil if there was a problem. If a file named filename is not found, the function will look for it in the $: path array.

Examples:

lines = LineCache::getline('/tmp/myfile.rb)
# Same as above
$: << '/tmp'
lines = Dir.chdir('/tmp') do 
   lines = LineCache::getlines ('myfile.rb')
end



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# File 'lib/linecache.rb', line 186

def getline(filename, line_number, reload_on_change=true)
  filename = unmap_file(filename)
  filename, line_number = unmap_file_line(filename, line_number)
  lines = getlines(filename, reload_on_change)
  if lines and (1..lines.size) === line_number
      return lines[line_number-1]
  else
      return nil
  end
end

.getlines(filename, reload_on_change = false) ⇒ Object

Read lines of filename and cache the results. However filename was previously cached use the results from the cache. Return nil if we can’t get lines



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# File 'lib/linecache.rb', line 201

def getlines(filename, reload_on_change=false)
  filename = unmap_file(filename)
  checkcache(filename) if reload_on_change
  if @@file_cache.member?(filename)
    return @@file_cache[filename].lines
  else
    update_cache(filename, true)
    return @@file_cache[filename].lines if @@file_cache.member?(filename)
  end
end

.path(filename) ⇒ Object

Return full filename path for filename



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# File 'lib/linecache.rb', line 214

def path(filename)
  filename = unmap_file(filename)
  return nil unless @@file_cache.member?(filename)
  @@file_cache[filename].path
end

.remap_file(from_file, to_file) ⇒ Object 



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# File 'lib/linecache.rb', line 221

def remap_file(from_file, to_file)
  @@file2file_remap[to_file] = from_file
end

.remap_file_lines(from_file, to_file, range, start) ⇒ Object 



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# File 'lib/linecache.rb', line 226

def remap_file_lines(from_file, to_file, range, start)
  range = (range..range) if range.is_a?(Fixnum)
  to_file = from_file unless to_file
  if @@file2file_remap_lines[to_file] 
    # FIXME: need to check for overwriting ranges: whether
    # they intersect or one encompasses another.
    @@file2file_remap_lines[to_file] << [from_file, range, start]
  else
    @@file2file_remap_lines[to_file]  = [[from_file, range, start]]
  end
end

.sha1(filename) ⇒ Object

Return SHA1 of filename.



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# File 'lib/linecache.rb', line 240

def sha1(filename)
  filename = unmap_file(filename)
  return nil unless @@file_cache.member?(filename)
  return @@file_cache[filename].sha1.hexdigest if 
    @@file_cache[filename].sha1
  sha1 = Digest::SHA1.new
  @@file_cache[filename].lines.each do |line|
    sha1 << line
  end
  @@file_cache[filename].sha1 = sha1
  sha1.hexdigest
end

.size(filename) ⇒ Object

Return the number of lines in filename



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# File 'lib/linecache.rb', line 255

def size(filename)
  filename = unmap_file(filename)
  return nil unless @@file_cache.member?(filename)
  @@file_cache[filename].lines.length
end

.stat(filename) ⇒ Object

Return File.stat in the cache for filename.



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# File 'lib/linecache.rb', line 263

def stat(filename)
  return nil unless @@file_cache.member?(filename)
  @@file_cache[filename].stat
end

.trace_line_numbers(filename, reload_on_change = false) ⇒ Object

Return an Array of breakpoints in filename. The list will contain an entry for each distinct line event call so it is possible (and possibly useful) for a line number appear more than once.



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# File 'lib/linecache.rb', line 273

def trace_line_numbers(filename, reload_on_change=false)
  fullname = cache(filename, reload_on_change)
  return nil unless fullname
  e = @@file_cache[filename]
  unless e.line_numbers
    e.line_numbers = 
      TraceLineNumbers.lnums_for_str_array(e.lines)
    e.line_numbers = false unless e.line_numbers
  end
  e.line_numbers
end

.unmap_file(file) ⇒ Object 



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# File 'lib/linecache.rb', line 286

def unmap_file(file)
  @@file2file_remap[file] ? @@file2file_remap[file] : file
end

.unmap_file_line(file, line) ⇒ Object 



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# File 'lib/linecache.rb', line 291

def unmap_file_line(file, line)
  if @@file2file_remap_lines[file]
    @@file2file_remap_lines[file].each do |from_file, range, start|
      if range === line
        from_file = from_file || file 
        return [from_file, start+line-range.begin] 
      end
    end
  end
  return [file, line]
end

.update_cache(filename, use_script_lines = false) ⇒ Object

Update a cache entry. If something’s wrong, return nil. Return true if the cache was updated and false if not. If use_script_lines is true, use that as the source for the lines of the file



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# File 'lib/linecache.rb', line 308

def update_cache(filename, use_script_lines=false)

  return nil unless filename

  @@file_cache.delete(filename)
  path = File.expand_path(filename)
  
  if use_script_lines
    list = [filename]
    list << @@file2file_remap[path] if @@file2file_remap[path]
    list.each do |name| 
      if !SCRIPT_LINES__[name].nil? && SCRIPT_LINES__[name] != true
        begin 
          stat = File.stat(name)
        rescue
          stat = nil
        end
        lines = SCRIPT_LINES__[name]
        @@file_cache[filename] = LineCacheInfo.new(stat, nil, lines, path, nil)
        @@file2file_remap[path] = filename
        return true
      end
    end
  end
    
  if File.exist?(path)
    stat = File.stat(path)
  elsif File.basename(filename) == filename
    # try looking through the search path.
    stat = nil
    for dirname in $:
      path = File.join(dirname, filename)
      if File.exist?(path)
          stat = File.stat(path)
          break
      end
    end
    return false unless stat
  end
  begin
    fp = File.open(path, 'r')
    lines = fp.readlines()
    fp.close()
  rescue 
    ##  print '*** cannot open', path, ':', msg
    return nil
  end
  @@file_cache[filename] = LineCacheInfo.new(File.stat(path), nil, lines,
                                             path, nil)
  @@file2file_remap[path] = filename
  return true
end