Module: LineCache

Defined in:
lib/linecache.rb

Overview

module LineCache

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

Defined Under Namespace

Classes: LineCacheInfo

Constant Summary collapse

VERSION = 
'0.44'
@@file_cache =

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

{}
@@script_cache = 
{}
@@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 = 
{}
@@script2file = 
{}

Class Method Summary collapse

Instance Method Summary collapse

Class Method Details

.cache(file_or_script, reload_on_change = false) ⇒ Object

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



172
173
174
175
176
177
178
 
# File 'lib/linecache.rb', line 172

def cache(file_or_script, reload_on_change=false)
  if file_or_script.kind_of?(String)
    cache_file(file_or_script, reload_on_change)
  else
    cache_script(file_or_script)
  end
end

.cache_file(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.



184
185
186
187
188
189
190
191
192
193
194
195
 
# File 'lib/linecache.rb', line 184

def cache_file(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

.cache_script(script, string = nil, sha1 = nil) ⇒ Object

Cache script if it’s not already cached.



161
162
163
164
165
166
 
# File 'lib/linecache.rb', line 161

def cache_script(script, string=nil, sha1=nil)
  if !@@script_cache.member?(script)
    update_script_cache(script, string, sha1)
  end
  script
end

.cached?(file_or_script) ⇒ Boolean

Return true if file_or_script is cached

Returns:

  • (Boolean) 


199
200
201
202
203
204
205
 
# File 'lib/linecache.rb', line 199

def cached?(file_or_script)
  if file_or_script.kind_of?(String) 
    @@file_cache.member?(map_file(file_or_script))
  else 
    cached_script?(file_or_script)
  end
end

.cached_files ⇒ Object

Return an array of cached file names



116
117
118
 
# File 'lib/linecache.rb', line 116

def cached_files()
  @@file_cache.keys
end

.cached_script?(script) ⇒ Boolean

Returns:

  • (Boolean) 


208
209
210
 
# File 'lib/linecache.rb', line 208

def cached_script?(script)
    @@script_cache.member?(script)
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.



127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
 
# File 'lib/linecache.rb', line 127

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 cache_info
        if stat && 
            (cache_info.size != stat.size or cache_info.mtime != stat.mtime)
          result << filename
          update_cache(filename, use_script_lines)
        end
      else
        result << filename
        update_cache(filename, use_script_lines)
      end
    end
  end
  return result
end

.clear_file_cache ⇒ Object

Clear the file cache entirely.



102
103
104
105
106
 
# File 'lib/linecache.rb', line 102

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

.empty?(filename) ⇒ Boolean

Returns:

  • (Boolean) 


213
214
215
216
 
# File 'lib/linecache.rb', line 213

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

.getline(file_or_script, 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')



230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
 
# File 'lib/linecache.rb', line 230

def getline(file_or_script, line_number, reload_on_change=true)
  lines = 
    if file_or_script.kind_of?(String)
      filename = map_file(file_or_script)
      filename, line_number = map_file_line(filename, line_number)
      getlines(filename, reload_on_change)
    else
      script_getlines(file_or_script)
    end
  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



267
268
269
270
271
272
273
274
275
276
277
278
279
280
 
# File 'lib/linecache.rb', line 267

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

.map_file(file) ⇒ Object 



363
364
365
 
# File 'lib/linecache.rb', line 363

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

.map_file_line(file, line) ⇒ Object 



387
388
389
390
391
392
393
394
395
396
397
 
# File 'lib/linecache.rb', line 387

def map_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 [map_file(file), line]
end

.map_script(script) ⇒ Object 



368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
 
# File 'lib/linecache.rb', line 368

def map_script(script)
  if @@script2file[script] 
    @@script2file[script] 
  else 
    # Doc says there's new takes an optional string parameter
    # But it doesn't work for me
    sha1 = Digest::SHA1.new
    string = script.eval_source
    sha1 << script.eval_source
    tempfile = Tempfile.new(["eval-#{sha1.hexdigest[0...7]}-", '.rb'])
    tempfile.open.puts(string)
    tempfile.close
    # cache_script(script, string, sha1.hexdigest)
    @@script2file[script] = tempfile.path
    tempfile.path
  end
end

.path(filename) ⇒ Object

Return full filename path for filename



284
285
286
287
288
289
 
# File 'lib/linecache.rb', line 284

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

.remap_file(to_file, from_file) ⇒ Object 



292
293
294
 
# File 'lib/linecache.rb', line 292

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

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



297
298
299
300
301
302
303
304
305
306
307
 
# File 'lib/linecache.rb', line 297

def remap_file_lines(from_file, to_file, range, start)
  range = (range..range) if range.kind_of?(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

.remove_script_temps ⇒ Object 



92
93
94
95
96
 
# File 'lib/linecache.rb', line 92

def remove_script_temps
  @@script2file.values.each do |filename|
    File.unlink(filename)
  end
end

.script_getlines(script) ⇒ Object

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



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

def script_getlines(script)
  if @@script_cache.member?(script)
    return @@script_cache[script].lines
  else
    update_script_cache(script)
    if @@script_cache.member?(script)
      return @@script_cache[script].lines 
    else
      return nil
    end
  end
end

.script_is_eval?(script) ⇒ Boolean

Returns:

  • (Boolean) 


400
401
402
 
# File 'lib/linecache.rb', line 400

def script_is_eval?(script)
  !!script.eval_source
end

.sha1(filename) ⇒ Object

Return SHA1 of filename.



311
312
313
314
315
316
317
318
319
320
321
322
 
# File 'lib/linecache.rb', line 311

def sha1(filename)
  filename = map_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 + "\n"
  end
  @@file_cache[filename].sha1 = sha1
  sha1.hexdigest
end

.size(file_or_script) ⇒ Object

Return the number of lines in filename



326
327
328
329
330
331
332
333
334
335
336
 
# File 'lib/linecache.rb', line 326

def size(file_or_script)
  cache(file_or_script)
  if file_or_script.kind_of?(String)
    file_or_script = map_file(file_or_script)
    return nil unless @@file_cache.member?(file_or_script)
    @@file_cache[file_or_script].lines.length
  else
    return nil unless @@script_cache.member?(file_or_script)
    @@script_cache[file_or_script].lines.length
  end
end

.stat(filename) ⇒ Object

Return File.stat in the cache for filename.



340
341
342
343
 
# File 'lib/linecache.rb', line 340

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.



350
351
352
353
354
355
356
357
358
359
360
 
# File 'lib/linecache.rb', line 350

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

.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



420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
 
# File 'lib/linecache.rb', line 420

def update_cache(filename, use_script_lines=false)

  return nil unless filename

  @@file_cache.delete(filename)
  path = File.expand_path(filename)
  
  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

.update_script_cache(script, string = nil, sha1 = nil) ⇒ Object

Update a cache entry. If something is wrong, return nil. Return true if the cache was updated and false if not.



407
408
409
410
411
412
413
 
# File 'lib/linecache.rb', line 407

def update_script_cache(script, string=nil, sha1=nil)
  return false unless script_is_eval?(script)
  string = script.eval_source unless string
  @@script_cache[script] = 
    LineCacheInfo.new(nil, nil, string.split(/\n/), nil, sha1)
  return true
end

Instance Method Details

#clear_script_cache ⇒ Object

Clear the script cache entirely.



110
111
112
 
# File 'lib/linecache.rb', line 110

def clear_script_cache()
  @@script_cache = {}
end