Mass Deface ' % (self.steps,) def reset(self): """t.reset() restores a pipeline template to its initial state.""" self.steps = [] def clone(self): """t.clone() returns a new pipeline template with identical initial state as the current one.""" t = Template() t.steps = self.steps[:] t.debugging = self.debugging return t def debug(self, flag): """t.debug(flag) turns debugging on or off.""" self.debugging = flag def append(self, cmd, kind): """t.append(cmd, kind) adds a new step at the end.""" if type(cmd) is not type(''): raise TypeError, \ 'Template.append: cmd must be a string' if kind not in stepkinds: raise ValueError, \ 'Template.append: bad kind %r' % (kind,) if kind == SOURCE: raise ValueError, \ 'Template.append: SOURCE can only be prepended' if self.steps and self.steps[-1][1] == SINK: raise ValueError, \ 'Template.append: already ends with SINK' if kind[0] == 'f' and not re.search(r'\$IN\b', cmd): raise ValueError, \ 'Template.append: missing $IN in cmd' if kind[1] == 'f' and not re.search(r'\$OUT\b', cmd): raise ValueError, \ 'Template.append: missing $OUT in cmd' self.steps.append((cmd, kind)) def prepend(self, cmd, kind): """t.prepend(cmd, kind) adds a new step at the front.""" if type(cmd) is not type(''): raise TypeError, \ 'Template.prepend: cmd must be a string' if kind not in stepkinds: raise ValueError, \ 'Template.prepend: bad kind %r' % (kind,) if kind == SINK: raise ValueError, \ 'Template.prepend: SINK can only be appended' if self.steps and self.steps[0][1] == SOURCE: raise ValueError, \ 'Template.prepend: already begins with SOURCE' if kind[0] == 'f' and not re.search(r'\$IN\b', cmd): raise ValueError, \ 'Template.prepend: missing $IN in cmd' if kind[1] == 'f' and not re.search(r'\$OUT\b', cmd): raise ValueError, \ 'Template.prepend: missing $OUT in cmd' self.steps.insert(0, (cmd, kind)) def open(self, file, rw): """t.open(file, rw) returns a pipe or file object open for reading or writing; the file is the other end of the pipeline.""" if rw == 'r': return self.open_r(file) if rw == 'w': return self.open_w(file) raise ValueError, \ 'Template.open: rw must be \'r\' or \'w\', not %r' % (rw,) def open_r(self, file): """t.open_r(file) and t.open_w(file) implement t.open(file, 'r') and t.open(file, 'w') respectively.""" if not self.steps: return open(file, 'r') if self.steps[-1][1] == SINK: raise ValueError, \ 'Template.open_r: pipeline ends width SINK' cmd = self.makepipeline(file, '') return os.popen(cmd, 'r') def open_w(self, file): if not self.steps: return open(file, 'w') if self.steps[0][1] == SOURCE: raise ValueError, \ 'Template.open_w: pipeline begins with SOURCE' cmd = self.makepipeline('', file) return os.popen(cmd, 'w') def copy(self, infile, outfile): return os.system(self.makepipeline(infile, outfile)) def makepipeline(self, infile, outfile): cmd = makepipeline(infile, self.steps, outfile) if self.debugging: print cmd cmd = 'set -x; ' + cmd return cmd def makepipeline(infile, steps, outfile): # Build a list with for each command: # [input filename or '', command string, kind, output filename or ''] list = [] for cmd, kind in steps: list.append(['', cmd, kind, '']) # # Make sure there is at least one step # if not list: list.append(['', 'cat', '--', '']) # # Take care of the input and output ends # [cmd, kind] = list[0][1:3] if kind[0] == 'f' and not infile: list.insert(0, ['', 'cat', '--', '']) list[0][0] = infile # [cmd, kind] = list[-1][1:3] if kind[1] == 'f' and not outfile: list.append(['', 'cat', '--', '']) list[-1][-1] = outfile # # Invent temporary files to connect stages that need files # garbage = [] for i in range(1, len(list)): lkind = list[i-1][2] rkind = list[i][2] if lkind[1] == 'f' or rkind[0] == 'f': (fd, temp) = tempfile.mkstemp() os.close(fd) garbage.append(temp) list[i-1][-1] = list[i][0] = temp # for item in list: [inf, cmd, kind, outf] = item if kind[1] == 'f': cmd = 'OUT=' + quote(outf) + '; ' + cmd if kind[0] == 'f': cmd = 'IN=' + quote(inf) + '; ' + cmd if kind[0] == '-' and inf: cmd = cmd + ' <' + quote(inf) if kind[1] == '-' and outf: cmd = cmd + ' >' + quote(outf) item[1] = cmd # cmdlist = list[0][1] for item in list[1:]: [cmd, kind] = item[1:3] if item[0] == '': if 'f' in kind: cmd = '{ ' + cmd + '; }' cmdlist = cmdlist + ' |\n' + cmd else: cmdlist = cmdlist + '\n' + cmd # if garbage: rmcmd = 'rm -f' for file in garbage: rmcmd = rmcmd + ' ' + quote(file) trapcmd = 'trap ' + quote(rmcmd + '; exit') + ' 1 2 3 13 14 15' cmdlist = trapcmd + '\n' + cmdlist + '\n' + rmcmd # return cmdlist # Reliably quote a string as a single argument for /bin/sh # Safe unquoted _safechars = frozenset(string.ascii_letters + string.digits + '@%_-+=:,./') def quote(file): """Return a shell-escaped version of the file string.""" for c in file: if c not in _safechars: break else: if not file: return "''" return file # use single quotes, and put single quotes into double quotes # the string $'b is then quoted as '$'"'"'b' return "'" + file.replace("'", "'\"'\"'") + "'"