Source Code for Module common.latex

  1  # -*- coding:utf-8 -*- 
  2  ## src/common/latex.py 
  3  ## 
  4  ## Copyright (C) 2005 Norman Rasmussen <norman AT rasmussen.co.za> 
  5  ## Copyright (C) 2005-2006 Alex Mauer <hawke AT hawkesnest.net> 
  6  ##                         Travis Shirk <travis AT pobox.com> 
  7  ## Copyright (C) 2005-2007 Nikos Kouremenos <kourem AT gmail.com> 
  8  ## Copyright (C) 2005-2010 Yann Leboulanger <asterix AT lagaule.org> 
  9  ## Copyright (C) 2006 Dimitur Kirov <dkirov AT gmail.com> 
 10  ## Copyright (C) 2006-2008 Jean-Marie Traissard <jim AT lapin.org> 
 11  ## Copyright (C) 2008 Jonathan Schleifer <js-gajim AT webkeks.org> 
 12  ##                    Julien Pivotto <roidelapluie AT gmail.com> 
 13  ##                    Stephan Erb <steve-e AT h3c.de> 
 14  ## 
 15  ## This file is part of Gajim. 
 16  ## 
 17  ## Gajim is free software; you can redistribute it and/or modify 
 18  ## it under the terms of the GNU General Public License as published 
 19  ## by the Free Software Foundation; version 3 only. 
 20  ## 
 21  ## Gajim is distributed in the hope that it will be useful, 
 22  ## but WITHOUT ANY WARRANTY; without even the implied warranty of 
 23  ## MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 
 24  ## GNU General Public License for more details. 
 25  ## 
 26  ## You should have received a copy of the GNU General Public License 
 27  ## along with Gajim. If not, see <http://www.gnu.org/licenses/>. 
 28  ## 
 29   
 30  import os 
 31  import random 
 32  from tempfile import gettempdir 
 33  from subprocess import Popen, PIPE 
 34   
 35  import logging 
 36  log = logging.getLogger('gajim.c.latex') 
 37   
 38  import gajim 
 39  from exceptions import LatexError 
 40  import helpers 
 41   
 42  # some latex commands are really bad 
 43  blacklist = ['\\def', '\\let', '\\futurelet', 
 44          '\\newcommand', '\\renewcomment', '\\else', '\\fi', '\\write', 
 45          '\\input', '\\include', '\\chardef', '\\catcode', '\\makeatletter', 
 46          '\\noexpand', '\\toksdef', '\\every', '\\errhelp', '\\errorstopmode', 
 47          '\\scrollmode', '\\nonstopmode', '\\batchmode', '\\read', '\\csname', 
 48          '\\newhelp', '\\relax', '\\afterground', '\\afterassignment', 
 49          '\\expandafter', '\\noexpand', '\\special', '\\command', '\\loop', 
 50          '\\repeat', '\\toks', '\\output', '\\line', '\\mathcode', '\\name', 
 51          '\\item', '\\section', '\\mbox', '\\DeclareRobustCommand', '\\[', 
 52          '\\]'] 
 53  # True if the string matches the blacklist 
 54 -def check_blacklist(str_): 
 55      for word in blacklist: 
 56          if word in str_: 
 57              return True 
 58      return False 
 59   
 60 -def get_tmpfile_name(): 
 61      random.seed() 
 62      int_ = random.randint(0, 100) 
 63      return os.path.join(gettempdir(), 'gajimtex_' + int_.__str__()) 
 64   
 65 -def write_latex(filename, str_): 
 66      texstr = '\\documentclass[12pt]{article}\\usepackage[dvips]{graphicx}' 
 67      texstr += '\\usepackage{amsmath}\\usepackage{amssymb}' 
 68      texstr += '\\pagestyle{empty}' 
 69      texstr += '\\begin{document}\\begin{large}\\begin{gather*}' 
 70      texstr += str_ 
 71      texstr += '\\end{gather*}\\end{large}\\end{document}' 
 72   
 73      file_ = open(filename, "w+") 
 74      file_.write(texstr) 
 75      file_.flush() 
 76      file_.close() 
 77   
 78  # a wrapper for Popen so that no window gets opened on Windows 
 79  # (i think this is the reason we're using Popen rather than just system()) 
 80  # stdout goes to a pipe so that it can be read 
 81 -def popen_nt_friendly(command): 
 82      if os.name == 'nt': 
 83          # CREATE_NO_WINDOW 
 84          return Popen(command, creationflags=0x08000000, cwd=gettempdir(), stdout=PIPE) 
 85      else: 
 86          return Popen(command, cwd=gettempdir(), stdout=PIPE) 
 87   
 88 -def check_for_latex_support(): 
 89      """ 
 90      Check if latex is available and if it can create a picture 
 91      """ 
 92      try: 
 93          filename = latex_to_image("test") 
 94          if filename: 
 95              # we have a file, conversion succeeded 
 96              os.remove(filename) 
 97              return True 
 98          return False 
 99      except LatexError: 
100          return False 
101   
102 -def try_run(argv): 
103      try: 
104          p = popen_nt_friendly(argv) 
105          out = p.communicate()[0] 
106          log.info(out) 
107          return p.wait() 
108      except Exception, e: 
109          return _('Error executing "%(command)s": %(error)s') % { 
110                  'command': " ".join(argv), 
111                  'error': helpers.decode_string(str(e))} 
112   
113   
114 -def latex_to_image(str_): 
115      result = None 
116      exitcode = 0 
117   
118      try: 
119          bg_str, fg_str = gajim.interface.get_bg_fg_colors() 
120      except: 
121          # interface may not be available when we test latext at startup 
122          bg_str, fg_str = 'rgb 1.0 1.0 1.0', 'rgb 0.0 0.0 0.0' 
123   
124      # filter latex code with bad commands 
125      if check_blacklist(str_): 
126          # we triggered the blacklist, immediately return None 
127          return None 
128   
129      tmpfile = get_tmpfile_name() 
130   
131      # build latex string 
132      write_latex(os.path.join(tmpfile + '.tex'), str_) 
133   
134      # convert TeX to dvi 
135      exitcode = try_run(['latex', '--interaction=nonstopmode', 
136                        tmpfile + '.tex']) 
137   
138      if exitcode == 0: 
139          # convert dvi to png 
140          latex_png_dpi = gajim.config.get('latex_png_dpi') 
141          exitcode = try_run(['dvipng', '-bg', bg_str, '-fg', fg_str, '-T', 
142                          'tight', '-D', latex_png_dpi, tmpfile + '.dvi', '-o', 
143                          tmpfile + '.png']) 
144   
145      # remove temp files created by us and TeX 
146      extensions = ['.tex', '.log', '.aux', '.dvi'] 
147      for ext in extensions: 
148          try: 
149              os.remove(tmpfile + ext) 
150          except Exception: 
151              pass 
152   
153      if isinstance(exitcode, (unicode, str)): 
154          raise LatexError(exitcode) 
155   
156      if exitcode == 0: 
157          result = tmpfile + '.png' 
158   
159      return result 
160