Edit File: shvfile.py
# # shvfile.py # # Implementation of non-destructively reading/writing files containing # only shell variable declarations and full-line comments. # # Copyright 1999 - 2005 Red Hat, Inc. # # This is free software; you can redistribute it and/or modify it # under the terms of the GNU General Public License as published by # the Free Software Foundation; either version 2 of the License, or # (at your option) any later version. # # This program is distributed in the hope that it will be useful, but # WITHOUT ANY WARRANTY; without even the implied warranty of # MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU # General Public License for more details. # # You should have received a copy of the GNU General Public License # along with this program; if not, write to the Free Software Foundation, # Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA. # import os def read(filename): shv = SHVFile() shv.open(filename, "r") shv.parse() return shv def rcreate(filename): shv = SHVFile() shv.open(filename, "r+") shv.parse() return shv # remove escaped characters in place def unescape(s): if not s: return s slen = len(s) if (s[0] == "\"" or s[0] == "'") and s[0] == s[slen-1]: s = s[1:slen-1] i = 0 while True: i = s.find("\\", i) if i < 0: break if i+1 >= len(s): s = s[0:i] break s = s[0:i] + s[i+1:] i += 1 return s # create a new string with all necessary characters escaped. def escape(s): s = s.replace("\\", "\\\\") s = s.replace("\"", "\\\"") s = s.replace("'", "\\\'") s = s.replace("$", "\\\$") s = s.replace("~", "\\\~") s = s.replace("`", "\\\`") if s.find(" ") > 0 or s.find("\t") > 0: s = "\"" + s + "\"" return s class SHVFile: def __init__(self): self.filename = "" self.f = None self.variables = {} def open(self, filename, mode): self.filename = filename if mode == "r": self.f = open(filename, mode) else: try: self.f = open(filename, mode) except IOError: pass return def parse(self): if not self.f: return for line in self.f: vs = line.rstrip().split("=",1) if len(vs) < 2: continue self.variables[vs[0]] = unescape(vs[1]) def write(self, perms): if not self.f: try: fd = os.open(self.filename, os.O_RDWR | os.O_CREAT, perms) except OSError: return try: self.f = os.fdopen(fd, "w") except IOError: os.close(fd) return try: self.f.seek(0) self.f.truncate() ordereditems = self.variables.items() ordereditems.sort(lambda x, y: cmp(x[0], y[0])) for name, value in ordereditems: self.f.write(name + "=" + escape(value) + "\n") self.f.flush() os.fsync(self.f.fileno()) except IOError: # we cannot do much in case of error anyway pass def close(self): if self.f: try: self.f.close() except IOError: # we cannot do much in case of error anyway pass self.f = None def getValue(self, name): try: return self.variables[name] except KeyError: return "" def getBoolValue(self, name): # return True if <key> resolves to any truth value (e.g. "yes", "y", "true") # return False if <key> resolves to any non-truth value (e.g. "no", "n", "false") # raise ValueError otherwise try: val = self.variables[name].lower() except KeyError: raise ValueError if val == "yes" or val == "true" or val == "t" or val == "y": return True if val == "no" or val == "false" or val == "f" or val == "n": return False raise ValueError def setValue(self, name, value): if not value: if name in self.variables: del self.variables[name] else: self.variables[name] = value def setBoolValue(self, name, value): if value: self.variables[name] = "yes" else: self.variables[name] = "no"