Module: LineCache

Defined in:
lib/linecache19.rb

Overview

module LineCache

A module to read and cache lines of a Ruby program.

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.



148
149
150
151
152
153
154
155
156
157
158
159
 
# File 'lib/linecache19.rb', line 148

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) 


163
164
165
 
# File 'lib/linecache19.rb', line 163

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

.cached_files ⇒ Object

Return an array of cached file names



106
107
108
 
# File 'lib/linecache19.rb', line 106

def cached_files()
  @@file_cache.keys
end

.cached_script?(filename) ⇒ Boolean

Returns:

  • (Boolean) 


168
169
170
171
172
173
174
175
176
 
# File 'lib/linecache19.rb', line 168

def cached_script?(filename)
  # In 1.8.6, the SCRIPT_LINES__ filename key can be unqualified
  # In 1.9.1 it's the fully qualified name
  if RUBY_VERSION < "1.9"
    SCRIPT_LINES__.member?(unmap_file(filename))
  else
    SCRIPT_LINES__.member?(File.expand_path(unmap_file(filename)))
  end
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Discard cache entries that are out of date.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.



117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
 
# File 'lib/linecache19.rb', line 117

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
      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.



98
99
100
101
102
 
# File 'lib/linecache19.rb', line 98

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

.empty?(filename) ⇒ Boolean

Returns:

  • (Boolean) 


179
180
181
182
 
# File 'lib/linecache19.rb', line 179

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 $: array.

Examples:

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



196
197
198
199
200
201
202
203
204
205
 
# File 'lib/linecache19.rb', line 196

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



211
212
213
214
215
216
217
218
219
220
 
# File 'lib/linecache19.rb', line 211

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



224
225
226
227
228
 
# File 'lib/linecache19.rb', line 224

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 



231
232
233
 
# File 'lib/linecache19.rb', line 231

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

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



236
237
238
239
240
241
242
243
244
245
246
 
# File 'lib/linecache19.rb', line 236

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.



250
251
252
253
254
255
256
257
258
259
260
261
 
# File 'lib/linecache19.rb', line 250

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



265
266
267
268
269
 
# File 'lib/linecache19.rb', line 265

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.



273
274
275
276
 
# File 'lib/linecache19.rb', line 273

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.



283
284
285
286
287
288
289
290
291
292
293
 
# File 'lib/linecache19.rb', line 283

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 



296
297
298
 
# File 'lib/linecache19.rb', line 296

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

.unmap_file_line(file, line) ⇒ Object 



301
302
303
304
305
306
307
308
309
310
311
 
# File 'lib/linecache19.rb', line 301

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



318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
 
# File 'lib/linecache19.rb', line 318

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