#!/usr/bin/env python
# tconfpy.py
# Copyright (c) 2003-2005 TundraWare Inc. All Rights Reserved.
# For Updates See: http://www.tundraware.com/Software/tconfpy
# Program Information
PROGNAME = "tconfpy"
RCSID = "$Id: tconfpy.py,v 1.187 2005/01/13 20:45:50 tundra Exp $"
VERSION = RCSID.split()[2]
# Copyright Information
CPRT = chr(169)
DATE = "2003-2005"
OWNER = "TundraWare Inc."
RIGHTS = "All Rights Reserved"
COPYRIGHT = "Copyright %s %s %s, %s." % (CPRT, DATE, OWNER, RIGHTS)
PROGINFO = PROGNAME + " " + VERSION
BANNER = "%s\n%s\n%s\n" % (PROGINFO, COPYRIGHT, RCSID)
#----------------------------------------------------------#
# Variables User Might Change #
#----------------------------------------------------------#
#------------------- Nothing Below Here Should Need Changing -----------------#
#----------------------------------------------------------#
# Imports #
#----------------------------------------------------------#
import os
import platform
import re
from sys import platform as sysplat
#----------------------------------------------------------#
# Aliases & Redefinitions #
#----------------------------------------------------------#
#----------------------------------------------------------#
# Constants & Literals #
#----------------------------------------------------------#
###########
# Constants
###########
# Formatting Constants
ATEOF = "EOF" # Use as line number when at EOF
FILENUM = "[File: %s Line: %s] " # Display filename and linenum
MSGPROMPT = "%s>"
PTR = " ---> " # Textual pointer for debug output
STARTUP = "STARTUP" # Indicates message before any lines processed
# Special And Reserved Symbols
HASH = r'#'
COMMENT = HASH # Comment introducer character
DELIML = r'[' # Left delimiter for vbl reference
DELIMR = r']' # Right delimiter for vbl reference
DOLLAR = r'$'
ENVIRO = DOLLAR # Used to note environment variable
EQUAL = r'=' # Used in vbl definition
EQUIV = r"==" # Used in conditional tests
NAMESPACE = "NAMESPACE" # Key used to get current namespace
PERIOD = r'.'
NSSEP = PERIOD # Namespace separator character
NOTEQUIV = r"!=" # Used in conditional tests
# Control and conditional symbols
CONDINTRO = PERIOD # Conditional introducer token
INCLUDE = CONDINTRO + "include"
IF = CONDINTRO + "if"
IFALL = IF + "all"
IFANY = IF + "any"
IFNONE = IF + "none"
ELSE = CONDINTRO + "else"
ENDIF = CONDINTRO + "endif"
LITERAL = CONDINTRO + "literal"
ENDLITERAL = CONDINTRO + "endliteral"
# Pre-Defined System Symbols
PREDEFINTRO = PERIOD
Predefined = {"DELIML" : DELIML,
"DELIMR" : DELIMR,
"DOLLAR" : DOLLAR,
"ELSE" : ELSE,
"ENDIF" : ENDIF,
"ENDLITERAL" : ENDLITERAL,
"EQUAL" : EQUAL,
"EQUIV" : EQUIV,
"HASH" : HASH,
"IF" : IF,
"IFALL" : IFALL,
"IFANY" : IFANY,
"IFNONE" : IFNONE,
"INCLUDE" : INCLUDE,
"LITERAL" : LITERAL,
"NOTEQUIV" : NOTEQUIV,
"PERIOD" : PERIOD,
PREDEFINTRO + "MACHINENAME" : platform.node(),
PREDEFINTRO + "OSDETAILS" : platform.platform(),
PREDEFINTRO + "OSNAME" : platform.system(),
PREDEFINTRO + "OSRELEASE" : platform.release(),
PREDEFINTRO + "OSTYPE" : sysplat,
PREDEFINTRO + "PLATFORM" : os.name,
PREDEFINTRO + "PYTHONVERSION" : platform.python_version()
}
# Symbols Illegal Anywhere In A Variable/Namespace Name
IllegalChars = (DELIML, DELIMR, COMMENT)
# Regular Expressions
reVARWHITE = r".*\s+.*" # Look for embedded whitespace
reVARREF = r"\%s.+?\%s" % (DELIML, DELIMR) # Variable reference
VarWhite = re.compile(reVARWHITE)
VarRef = re.compile(reVARREF)
###########
# Literals
###########
# String Representations Of Booleans
Booleans = {"1" : True, "0" : False,
"True" : True, "False" : False,
"Yes" : True, "No" : False,
"On" : True, "Off" : False
}
sFALSE = "False"
sTRUE = "True"
#----------------------------------------------------------#
# Global Variables & Data Structures #
#----------------------------------------------------------#
##########
# Symbol Table Related Classes
##########
# Symbol Table is an object containing a dictionary in the form:
#
# {varname : descriptor}
#
class SymbolTable(object):
Symbols = {}
DebugMsgs = []
ErrMsgs = []
WarnMsgs = []
LiteralLines = []
ALLOWNEWVAR = True
TEMPLATES = {}
TEMPONLY = False
LITERALVARS = False
INLITERAL = False
DEBUG = False
CondStack = [["", True],] # Always has one entry as a sentinel
TotalLines = 0
# End of class 'SymbolTable'
# The descriptor is an object with the following attributes
#
# Value, Writeable, Type, Default, LegalVals = [list of legal vals], Min, Max]
#
# Legal Variable Types
TYPE_BOOL = type(True)
TYPE_COMPLEX = type(1-1j)
TYPE_FLOAT = type(3.14)
TYPE_INT = type(1)
TYPE_STRING = type('s')
# Object to hold full description and options for a given variable
class VarDescriptor(object):
# Default variable type is a writeable string with no constraints
def __init__(self):
self.Value = ""
self.Writeable = True
self.Type = TYPE_STRING
self.Default = ""
self.LegalVals = []
self.Min = None
self.Max = None
# End of class 'VarDescriptor'
SymTable = SymbolTable()
for var in Predefined.keys():
d = VarDescriptor()
d.Value = Predefined[var]
d.Writeable = False
SymTable.Symbols[var] = d
##########
# Error, Warning, And Debug Message Strings Stored In A Global Dictionary
##########
Messages = {}
#----------------------------------------------------------#
# Prompts, & Application Strings #
#----------------------------------------------------------#
##########
# Debug Literals And Messages
##########
# Debug Literals
dDEBUG = "DEBUG"
dLINEIGNORE = "Line Ignored"
dBLANKLINE = "Parsed To Blank Line. %s" % dLINEIGNORE
dNOTINCLUDE = "Current Conditional Block False. %s" % dLINEIGNORE
# Debug Messages
Messages["dLINEIGNORE"] = FILENUM + "'%s'" + PTR + "%s"
Messages["dNAMESPACE"] = FILENUM + "Setting Current Namespace To: '%s'"
Messages["dNUMLINES"] = "Processing File '%s' Resulted In %d Total Lines Parsed"
Messages["dPARSEDLINE"] = FILENUM + "'%s'" + PTR + "'%s'"
Messages["dREGEXMATCH"] = FILENUM + "Value '%s' Matched Regex '%s' For Variable '%s'"
Messages["dVAREXISTS"] = FILENUM + "Checking To See If Variable '%s' Exists"
Messages["dVARREF"] = FILENUM + "Variable Dereference: '%s'" + PTR + "'%s'"
###########
# Error Literals And Messages
###########
# Error Literals
eERROR = "ERROR"
eBADDEFAULT = "Type Of Default Value Does Not Agree With Type Declared"
eBADLEGALVAL = "Type Of One Or More LegalVals Does Not Agree With Type Declared"
eBADMINMAX = "Type Of Min Or Max Value Not Appropriate For"
eBADVARREF = "Attempt To Get Value Of Non-Existent Variable"
eIFBAD = "'%s' Or '%s' Missing" % (EQUIV, NOTEQUIV)
eLEGALVALLIST = "The LegalVal Attribute Is Wrong Type (Must Be A List)"
eNOTDESCRIPT = "Invalid Descriptor Type"
eNOVARS = "This Conditional Requires At Least One Variable Name To Test"
eSTARTUP = "<Program Starting>"
# Error Messages
Messages["eBADCOND"] = FILENUM + "Bad '%s' Directive. %s"
Messages["eBADREGEX"] = FILENUM + "Bad Regular Expression, '%s', In Legal Values List For Variable '%s'"
Messages["eBADSYNTAX"] = FILENUM + "Syntax Error. Statement Not In Known Form"
Messages["eCONFOPEN"] = FILENUM + "Cannot Open The File '%s'"
Messages["eDESCRIPTBAD"] = "API Error: %s For Variable '%s'"
Messages["eELSENOIF"] = FILENUM + "'%s' Without Preceding '%s' Form" % (ELSE, IF)
Messages["eENDIFEXTRA"] = FILENUM + "'" + ENDIF + "' Without Matching Condition"
Messages["eENDIFMISS"] = FILENUM + "Missing %d" + " '%s' " % ENDIF + " Statement(s)"
Messages["eEQUIVEXTRA"] = FILENUM + "Only a single '%s' Or '%s' Operator Permitted" % (EQUIV, NOTEQUIV)
Messages["eIFEXTRATXT"] = FILENUM + "Extra Text On Line. '%s' Only Accepts Variable References As Arguments"
Messages["eNOTLEGALVAL"] = FILENUM + "'%s' Not Found In List Of Legal Values For Variable '%s'"
Messages["eSTRINGLONG"] = FILENUM + "'%s' Too Long For Variable '%s'. Maximum Length Is %s"
Messages["eSTRINGSHORT"] = FILENUM + "'%s' Too Short For Variable '%s'. Minimum Length is %s"
Messages["eSYMBADCHAR"] = FILENUM + "Symbol '%s' Contains Illegal Character '%s'"
Messages["eSYMBADSTART"] = FILENUM + "Symbol '%s' Begins With An Illegal Character"
Messages["eSYMNAMESPC"] = FILENUM + "Symbol Names May Not Contain Whitespace"
Messages["eSYMNONAME"] = FILENUM + "Symbol Name Evaluates To Null String. Not Permitted"
Messages["eTEMPONLY"] = FILENUM + "Cannot Create New Variable. No Template For '%s'"
Messages["eTYPEBAD"] = FILENUM + "Type Mismatch. '%s' Must Be Assigned Values Of Type %s Only"
Messages["eVALLARGE"] = FILENUM + "%s Too Large For Variable '%s'. Maximum Allowed is %s"
Messages["eVALSMALL"] = FILENUM + "%s Too Small For Variable '%s'. Minimum Allowed is %s"
Messages["eVARNEW"] = FILENUM + "New Variable Creation Not Permitted"
Messages["eVARREADONLY"] = FILENUM + "Variable '%s' Is Read-Only. Cannot Change Its Value"
Messages["eVARREFNEST"] = FILENUM + "Nested Variable References Are Not Permitted"
Messages["eVARUNDEF"] = FILENUM + "Attempt To Reference Undefined Variable '%s'"
###########
# Warning Literals And Messages
###########
# Warning Literals
wWARNING = "WARNING"
# Warning Messages
Messages["wENDLITEXTRA"] = FILENUM + "'%s' Statement Without Preceding '%s'. Statement Ignored" % (ENDLITERAL, LITERAL)
Messages["wENDLITMISS"] = FILENUM + "Missing '%s' Statement. All lines treated literally to end-of-file" % ENDLITERAL
Messages["wLITEXTRA"] = FILENUM + "Already In A Literal Block. '%s' Statement Ignored" % LITERAL
# Determine Length Of Longest Message Name
MAXMSG = 0
for msg in Messages:
l = len(msg)
if l > MAXMSG:
MAXMSG = l
#--------------------------- Code Begins Here ---------------------------------#
#----------------------------------------------------------#
# Utility Function Definitions #
#----------------------------------------------------------#
##########
# Create A Debug Message
##########
def DebugMsg(dmsg, args):
global SymTable
SymTable.DebugMsgs.append(mkmsg(Messages[dmsg] % args, dmsg))
# End of 'DebugMsg()'
##########
# Create An Error Message
##########
def ErrorMsg(error, args):
global SymTable
SymTable.ErrMsgs.append(mkmsg(Messages[error] % args + "!", error))
# End of 'ErrorMsg()'
##########
# Create A Warning Message
##########
def WarningMsg(warning, args):
global SymTable
SymTable.WarnMsgs.append(mkmsg(Messages[warning] % args + "!", warning))
# End of 'WarningMsg()'
##########
# Construct A Standard Application Message String
##########
def mkmsg(msg, msgtype):
pad = " " * (MAXMSG - len(msgtype) + 2)
return "%s %s%s%s" % (mkmsg.proginfo, MSGPROMPT % msgtype, pad, msg)
# End of 'mkmsg()'
#----------------------------------------------------------#
# Public API To Module #
#----------------------------------------------------------#
def ParseConfig(cfgfile,
CallingProgram=PROGINFO,
InitialSymTable=SymbolTable(),
AllowNewVars=True,
Templates={},
TemplatesOnly=False,
LiteralVars=False,
ReturnPredefs=True,
Debug=False):
global SymTable
# Set the name of the calling program for output messages
mkmsg.proginfo = CallingProgram
# Create a new symbol table
SymTable = SymbolTable()
# Initialize the globals
SymTable.ALLOWNEWVAR = AllowNewVars
SymTable.TEMPLATES = Templates
SymTable.TEMPONLY = TemplatesOnly
SymTable.LITERALVARS = LiteralVars
SymTable.INLITERAL = False
SymTable.DEBUG = Debug
# Add any passed symbols to the SymbolTable
deserror = False
for sym in InitialSymTable.Symbols:
des = InitialSymTable.Symbols[sym]
# Make sure a valid descriptor was passed for each variable
desok = True
# Make sure we got a Var Descriptor Object
if not isinstance(des, VarDescriptor):
desok = False
ErrorMsg("eDESCRIPTBAD", (eNOTDESCRIPT, sym))
des = VarDescriptor() # Make a fake one so the following tests don't blow up
# Check various entries for type agreement
dt = des.Type
# Make sure default value agrees with variable type
if des.Default and type(des.Default) != dt:
desok = False
ErrorMsg("eDESCRIPTBAD", (eBADDEFAULT, sym))
# Make sure that LegalVals is a list type
if type(des.LegalVals) != type([]):
desok = False
ErrorMsg("eDESCRIPTBAD", (eLEGALVALLIST, sym))
# Then check each value in the list for type agreement
else:
for lv in des.LegalVals:
if type(lv) != dt:
desok = False
ErrorMsg("eDESCRIPTBAD", (eBADLEGALVAL, sym))
# Make sure min and max limits are of the correct type
for mm in (des.Min, des.Max):
# Floats can accept Float or Int boundaries
# Ints, & Strings can accept Int boundaries
# Boundaries not relevant for Bool and Complex
# Anything else is an error
if mm and dt == TYPE_FLOAT and type(mm) != TYPE_FLOAT and type(mm) != TYPE_INT:
desok = False
ErrorMsg("eDESCRIPTBAD", (eBADMINMAX, sym))
if mm and dt in (TYPE_INT, TYPE_STRING) and type(mm) != TYPE_INT:
desok = False
ErrorMsg("eDESCRIPTBAD", (eBADMINMAX, sym))
# Only load the symbol table with valid entries
if desok:
SymTable.Symbols[sym] = des
# Indicate that a problem was encountered
else:
deserror = True
# If any of the passed symbols had bogus descriptor contents, we're done
if deserror:
return SymTable
# Symbol Table passed to API was OK, so keep going
# Make sure the symbol table has a valid namespace
if NAMESPACE not in SymTable.Symbols:
SymTable.Symbols[NAMESPACE] = VarDescriptor()
SymTable.Symbols[NAMESPACE].Value = ""
# Otherwise, ensure that the initial namespace is properly formed.
# If not, revert to root namespace.
elif not ValidateSymbolName(SymTable.Symbols[NAMESPACE].Value, STARTUP, STARTUP, AllowEmpty=True):
SymTable.Symbols[NAMESPACE].Value = ""
# Report namespace to debug output
if SymTable.DEBUG:
DebugMsg("dNAMESPACE", (STARTUP, STARTUP, SymTable.Symbols[NAMESPACE].Value))
# Parse the file
ParseFile(cfgfile, eSTARTUP, 0)
# Make sure we had all condition blocks balanced with matching '.endif'
finalcond = len(SymTable.CondStack)
if finalcond != 1:
ErrorMsg("eENDIFMISS", (cfgfile, ATEOF, finalcond-1))
# Make sure we ended any literal processing properly
if SymTable.INLITERAL:
WarningMsg("wENDLITMISS", (cfgfile, ATEOF))
# Return the parsing results
if SymTable.DEBUG:
DebugMsg("dNUMLINES", (cfgfile, SymTable.TotalLines))
# Strip out Prefefined Variables if user does not want them
if not ReturnPredefs:
del SymTable.Symbols[NAMESPACE]
for sym in Predefined:
del SymTable.Symbols[sym]
return SymTable
# End of 'ParseConfig()'
#----------------------------------------------------------#
# Parser Support Functions #
#----------------------------------------------------------#
##########
# Condition A Line - Remove Comments & Leading/Trailing Whitespace
##########
def ConditionLine(line):
return line.split(COMMENT)[0].strip()
# End of 'ConditionLine()'
##########
# Dereference Variables
##########
def DerefVar(line, cfgfile, linenum, reporterr=True):
# Find all symbols refrences and replace w/sym table entry if present
ref_ok = True
for var in VarRef.findall(line):
sym = var[1:-1] # Strip delimiters
# Make sure symbol name is properly formed
ref_ok = ValidateSymbolName(sym, cfgfile, linenum, AllowEnviro=True)
# If Preliminary tests found errors - quit now
if not ref_ok:
return line, ref_ok
# By default, all variable names assumed to be relative to
# current namespace unless escaped with NSSEP. However,
# environment variables and predefined variables are always
# presumed to be relative to the top-level namespace and are
# left untouched here. This is also the case for the NAMESPACE
# variable.
if sym not in Predefined and sym != NAMESPACE and sym[0] != ENVIRO:
# Look for an escape. This makes the variable
# reference "absolute" (relative to the top-level namespace).
if sym and sym[0] == NSSEP:
sym = sym[1:]
# Prepend the current namespace unless we are in the top-level
# namespace.
elif SymTable.Symbols[NAMESPACE].Value:
sym = "%s%s%s" % (SymTable.Symbols[NAMESPACE].Value, NSSEP, sym)
# Handle environment variables
if sym and sym[0] == ENVIRO and sym[1:] in os.environ:
envvar = os.getenv(sym[1:])
line = line.replace(var, envvar)
if SymTable.DEBUG:
DebugMsg("dVARREF", (cfgfile, linenum, var, envvar))
# Handle variables in symbol table
elif sym in SymTable.Symbols:
symval = str(SymTable.Symbols[sym].Value)
line = line.replace(var, symval)
if SymTable.DEBUG:
DebugMsg("dVARREF", (cfgfile, linenum, var, symval))
# Reference to undefined variable
else:
# There are times a reference to an undefined variable
# should not produce and error message. For example,
# during existential conditional processing, we just
# want to check whether variables are defined or not.
# Attempts to reference undefined variables are legitimate
# in this case and ought not to generate an error message.
if reporterr:
ErrorMsg("eVARUNDEF", (cfgfile, linenum, sym))
ref_ok = False
return line, ref_ok
# End of 'DerefVar()'
##########
# Parse A File
##########
def ParseFile(cfgfile, current_cfg, current_linenum):
global MsgList, SymTable
linenum=0
try:
cf = open(cfgfile)
# Process and massage the configuration file
for line in cf.read().splitlines():
linenum += 1
SymTable.TotalLines += 1
# Parse this line
ParseLine(line, cfgfile, linenum)
# Close the config file
cf.close()
# File open failed for some reason
except IOError:
ErrorMsg("eCONFOPEN", (current_cfg, current_linenum, cfgfile)) # Record the error
# End of 'ParseFile()'
##########
# Parse A Line
##########
def ParseLine(line, cfgfile, linenum):
global MsgList, SymTable
orig = line # May need copy of original for debug output
##########
# Beginning Of Line Parser
##########
#####
# LITERAL and ENDLITERAL Processing
#
# These get highest precedence because they block everything else.
# We keep track of them even in False conditional blocks. This is
# so that the text within a literal block does not cause the the
# parser to throw a syntax error.
#####
if line.strip() in (LITERAL, ENDLITERAL):
if line.strip() == LITERAL:
if SymTable.INLITERAL:
WarningMsg("wLITEXTRA", (cfgfile, linenum))
else:
SymTable.INLITERAL = True
# Process ENDLITERAL statements
else:
if not SymTable.INLITERAL:
WarningMsg("wENDLITEXTRA", (cfgfile, linenum))
else:
SymTable.INLITERAL = False
if SymTable.DEBUG:
DebugMsg("dPARSEDLINE", (cfgfile, linenum, orig, line))
return
#####
# Process Content Of Literal Blocks
#
# We pass lines as-is, with optional variable replacement in
# literal blocks. But, only if we're inside a True conditional
# block.
#####
if SymTable.INLITERAL:
if SymTable.CondStack[-1][1]:
if SymTable.LITERALVARS:
line, ref_ok = DerefVar(line, cfgfile, linenum)
SymTable.LiteralLines.append(line)
if SymTable.DEBUG:
DebugMsg("dPARSEDLINE", (cfgfile, linenum, orig, line))
# Conditional block was false, so just throw away the line,
# noting in debug output if requested.
else:
if SymTable.DEBUG:
DebugMsg("dLINEIGNORE", (cfgfile, linenum, orig, dNOTINCLUDE))
return
#####
# Process All Other Cases
#####
line = ConditionLine(line) # Strip out comments and leading/trailing whitespace
condstate = True # Results of conditional tests kept here
# Only attempt on non-blank lines for everything else
# Line was blank
if not line:
# Note blank lines for debug purposes
if SymTable.DEBUG:
DebugMsg("dLINEIGNORE", (cfgfile, linenum, orig, dBLANKLINE))
return
# Get first token on the line
FIRSTTOK = line.split()[0]
#####
# ELSE Processing
#####
if line == ELSE:
# Get the enclosing block type and state
btyp, bst = SymTable.CondStack.pop()
# ELSE is only permitted after an immediately preceding IF form
if btyp != IF:
ErrorMsg("eELSENOIF", (cfgfile, linenum))
SymTable.CondStack.append(["", False]) # Error makes all that follows False
# We *are* in an IF block an ELSE is appropriate.
# To determine whether the ELSE should be taken or not we have
# to look at the state of that IF block AND the state of
# the block that contains the IF. This is because the IF
# block state is the AND of the state of its parent block
# and its own logical state - i.e. A block can be made
# logically False by its containing block even if the condition
# tested is True.
else:
# If the containing block is True, the contained IF state is legitimate.
# The ELSE inverts the IF state in that case.
if SymTable.CondStack[-1][1]:
SymTable.CondStack.append([ELSE, not bst])
# The containing block is false, so everything within it is also false
else:
SymTable.CondStack.append([ELSE, False])
if SymTable.DEBUG:
DebugMsg("dPARSEDLINE", (cfgfile, linenum, orig, line))
return
#####
# ENDIF Processing
#####
if line == ENDIF:
# Remove one level of conditional nesting
SymTable.CondStack.pop()
# Error, if there are more .endifs than conditionals
if not SymTable.CondStack:
ErrorMsg("eENDIFEXTRA", (cfgfile, linenum))
SymTable.CondStack.append(["", False]) # Restore sentinel & inhibit further parsing
if SymTable.DEBUG:
DebugMsg("dPARSEDLINE", (cfgfile, linenum, orig, line))
return
#####
# Namespace Processing
#####
# All we do here is detect the "[...]" form of the statement and
# convert it into a "NAMESPACE = ..." form. That way, the normal
# variable setting routines below can handle it as usual.
if line == DELIML+DELIMR or (len(VarRef.findall(line)) == 1 and \
line[0] == DELIML and line[-1] == DELIMR and\
line.count(DELIML) == line.count(DELIMR) == 1):
# Get the new namespace
line = "%s%s%s" % (NAMESPACE, EQUAL, line[1:-1])
#####
# INCLUDE Processing
#####
if FIRSTTOK == INCLUDE:
if not SymTable.CondStack[-1][1]:
if SymTable.DEBUG:
DebugMsg("dLINEIGNORE", (cfgfile, linenum, orig, dNOTINCLUDE))
return
line, ref_ok = DerefVar(line.split(INCLUDE)[1].strip(), cfgfile, linenum)
# Only attempt the include if all the variable dereferencing was successful
if ref_ok:
ParseFile(line, cfgfile, linenum)
if SymTable.DEBUG:
DebugMsg("dPARSEDLINE", (cfgfile, linenum, orig, line))
return
#####
# Conditional Processing
#
# Must be one of the following forms -
#
# IFALL [var] ...
# IFANY [var] ...
# IFNONE [var] ...
# IF string == string
# IF string != string
#
# where string can be any concatentation of text and variable references
#
#####
# Is it any of the IF forms?
elif FIRSTTOK in (IF, IFALL, IFANY, IFNONE):
#####
# Existential Conditionals
#####
if FIRSTTOK in (IFALL, IFANY, IFNONE):
if FIRSTTOK == IFALL:
line = line.split(IFALL)[1].strip()
elif FIRSTTOK == IFANY:
line = line.split(IFANY)[1].strip()
else:
line = line.split(IFNONE)[1].strip()
# Dereference any variables
line, ref_ok = DerefVar(line, cfgfile, linenum)
if ref_ok:
vars = line.split()
# There has to be at least one variable named
if vars:
numexist = 0
# Iterate through all named variables to see if they exist
for v in vars:
# Condition the variable name with the current namespace
# unless:
#
# 1) We are in the root namespace
# 2) We're dealing with an environment variable
# 3) We're dealing with a predefined variable
# 4) We're dealing with the NAMESPACE variable
# 5) The variable name is not escaped
ns = SymTable.Symbols[NAMESPACE].Value
if ns and \
v[0] != ENVIRO and \
v not in Predefined and \
v != NAMESPACE:
# Convert escaped variable names to canonical form
if v[0] == NSSEP:
v = v[1:]
# Prepend current namespace to everything else
else:
v = "%s%s%s" % (ns, NSSEP, v)
# Produce debug ouput of actual variable name being checked
if SymTable.DEBUG:
DebugMsg("dVAREXISTS", (cfgfile, linenum, v))
# Handle environment variables
if v[0] == ENVIRO:
if v[1:] in os.environ:
numexist += 1
# Handle local local variables
elif v in SymTable.Symbols:
numexist += 1
# And set the conditional state accordingly
if FIRSTTOK == IFALL and numexist != len(vars):
condstate = False
if FIRSTTOK == IFANY and numexist == 0:
condstate = False
if FIRSTTOK == IFNONE and numexist != 0:
condstate = False
# Bogus conditional syntax - no variables named
else:
ErrorMsg("eBADCOND", (cfgfile, linenum, FIRSTTOK, eNOVARS))
condstate = False
# Bogus conditional syntax - tried to reference non-existent variable
else:
ErrorMsg("eBADCOND", (cfgfile, linenum, FIRSTTOK, eBADVARREF))
condstate = False
#####
# (In)Equality Conditionals - IF string EQUIV/NOTEQUIV string forms
#####
else:
line = line.split(IF)[1].strip()
if EQUIV in line or NOTEQUIV in line:
# Only one operator permitted
if (line.count(EQUIV) + line.count(NOTEQUIV)) > 1:
ErrorMsg("eEQUIVEXTRA", (cfgfile, linenum))
condstate = False
else:
# Dereference all variables
line, ref_ok = DerefVar(line, cfgfile, linenum)
# Reference to undefined variables forces False
if not ref_ok:
condstate = False
# So does a failure of the equality test itself
else:
invert = False
operator = EQUIV
condstate = True
if operator not in line: # Must be NOTEQUIV
invert = True
operator = NOTEQUIV
line = line.split(operator)
if line[0].strip() != line[1].strip():
condstate = False
if invert:
condstate = not condstate
# Conditional Syntax Error
else:
ErrorMsg("eBADCOND", (cfgfile, linenum, FIRSTTOK, eIFBAD))
# Force parse state to False on an error
condstate = False
# Set parser state based on a successful conditional test
# But it has to be ANDed with the state of the enclosing block
enclosing = SymTable.CondStack[-1][1]
SymTable.CondStack.append([IF, condstate and enclosing])
# Now reflect this in the parsed line
line = sTRUE
if not condstate:
line = sFALSE
if SymTable.DEBUG:
DebugMsg("dPARSEDLINE", (cfgfile, linenum, orig, line))
return
#####
# Handle Variable Declaration/Assignment
#####
# If we got here it means that none of the conditional forms
# were found, so the only thing left might be a variable
# definition/assignment.
elif EQUAL in line:
if not SymTable.CondStack[-1][1]:
if SymTable.DEBUG:
DebugMsg("dLINEIGNORE", (cfgfile, linenum, orig, dNOTINCLUDE))
return
# Catch attempts to dereference without name anywhere in the line
if line.count(DELIML + DELIMR):
ErrorMsg("eSYMNONAME", (cfgfile, linenum))
if SymTable.DEBUG:
DebugMsg("dPARSEDLINE", (cfgfile, linenum, orig, line))
return
# Do any necessary variable dereferencing
line, ref_ok = DerefVar(line, cfgfile, linenum)
# Only do this if all var references were valid
if ref_ok:
# Get left and right sides of the assignment
e = line.index(EQUAL)
l = line[:e].strip()
r = line[e+1:].strip()
# Make sure symbol name is properly formed
if not ValidateSymbolName(l, cfgfile, linenum):
pass # Validation function issues relevant error messages
# Suppress any attempt to change a RO variable
# ***NOTE***
#
# This test needs to happen here before any of the
# namespace stuff below. Doing it here guarantees we
# catch an attempt to modify one of the Predefined
# variables, which are always marked RO and are always
# relative to the top-level namespace. This way, we don't
# have to put in an explicit check to ignore Predefined
# variables in the namespace munging below. IOW, Don't
# move this test down into the body of the variable name
# processing where namespace fiddling takes place.
elif l in SymTable.Symbols and not SymTable.Symbols[l].Writeable:
ErrorMsg("eVARREADONLY", (cfgfile, linenum, l))
# Load variable into the symbol table
else:
# Munge the variable name to incorporate
# the current namespace
# The NAMESPACE variable is special, it is always
# relative to the root namespace.
if l in (NAMESPACE, NSSEP+NAMESPACE):
# Make sure it is in absolute format
varname = l = NAMESPACE
# Handle absolute variable references
elif l.startswith(NSSEP):
varname = l = l[1:]
# In all other cases prepend current namespace
else:
varname = l
ns = SymTable.Symbols[NAMESPACE].Value
# Top level namespace variables don't need
# separator.
if ns:
l = "%s%s%s" % (ns, NSSEP, l)
# If this is a newly defined variable, set its
# default to be this first value assigned and
# create the new entry
if l not in SymTable.Symbols:
# Only do this if new variable creation allowed
if SymTable.ALLOWNEWVAR:
# Rules for new variable creation:
#
# 1) If var has a template, use it
# 2) If var has no template, but TemplatesOnly=True -> Error
# 3) If var has no template, and TemplatesOnly=False -> Create new var
# Rule 1
if varname in SymTable.TEMPLATES:
# Create the new variable
SymTable.Symbols[l] = SymTable.TEMPLATES[varname]
# Load the proposed value only if valid
if ValidateValue(l, r, cfgfile, linenum):
SymTable.Symbols[l].Value = r
# If value is invalid, remove this
# variable. We cannot create a new
# variable on an error. Errors are
# actually reported by the validation
# function.
else:
del(SymTable.Symbols[l])
# Rule 2
elif SymTable.TEMPONLY:
ErrorMsg("eTEMPONLY", (cfgfile, linenum, varname))
# Rule 3
else:
# Build a new variable descriptor
d = VarDescriptor()
d.Default = r
d.Value = r
SymTable.Symbols[l] = d
# New vars not allowed
else:
ErrorMsg("eVARNEW", (cfgfile, linenum))
# Otherwise, update an existing entry. For existing
# entries, the update only takes place if all the
# validation tests specified in the descriptor are
# passed successfully.
else:
# If all the validation testing is OK, update the
# entry. The validation function produces any
# relevant errors.
if ValidateValue(l, r, cfgfile, linenum):
# Write the new value for this variable
# Translate various strings to their
# equivalent logical value for boolean
# variables first
if SymTable.Symbols[l].Type == TYPE_BOOL:
r = Booleans[r.capitalize()]
SymTable.Symbols[l].Value = r
# Produce debug output when we change namespaces
if SymTable.DEBUG and l == NAMESPACE:
DebugMsg("dNAMESPACE", (cfgfile, linenum, r))
if SymTable.DEBUG:
DebugMsg("dPARSEDLINE", (cfgfile, linenum, orig, line))
return
#####
# Line Format Is Not In One Of The Recognized Forms - Syntax Error
#####
else:
ErrorMsg("eBADSYNTAX", (cfgfile, linenum))
##########
# End Of Line Parser
##########
# End of 'ParseLine'
#####
# Ensure Symbol Name Is Properly Formed
#####
def ValidateSymbolName(sym, cfgfile, linenum, AllowEmpty=False, AllowEnviro=False):
sym_ok = True
# Check for whitespace
if VarWhite.match(sym):
ErrorMsg("eSYMNAMESPC", (cfgfile, linenum))
sym_ok = False
# Check for empty symbols if they are disallowed
if not AllowEmpty and not sym:
ErrorMsg("eSYMNONAME", (cfgfile, linenum))
sym_ok = False
# Check for illegal ENVIRO introducer
if not AllowEnviro and sym and sym[0] == ENVIRO:
ErrorMsg("eSYMBADSTART", (cfgfile, linenum, sym))
sym_ok = False
# Check for illegal characters in symbol name
for c in sym:
if c in IllegalChars:
ErrorMsg("eSYMBADCHAR", (cfgfile, linenum, sym, c))
sym_ok = False
# Return symbol validity
return sym_ok
# End Of 'ValidateSymbolName()'
#####
# Validate Value
#####
def ValidateValue(l, r, cfgfile, linenum):
update = True
# Do some special preprocessing for the NAMESPACE variable
if l == NAMESPACE:
# The root namespace is always permitted regardless of other
# restrictions the calling program may have put in place.
if not r:
return True
# Other NAMESPACE values must conform to the same rules
# as variable names
if not ValidateSymbolName(r, cfgfile, linenum, AllowEmpty=True):
update = False # Validation function issues appropriate errors
des = SymTable.Symbols[l]
typ = des.Type
lv = des.LegalVals
low = des.Min
up = des.Max
#####
# Type Enforcement
#####
# We try to coerce the new value into
# the specified type. If this works, we
# go on to the rest of the validation tests,
# otherwise mark the attempt as invalid.
try:
# Booleans are a special case - we accept only
# a limited number of strings on the RHS
if typ == TYPE_BOOL:
r = Booleans[r.capitalize()]
# For everything else, try an explicit coercion
else:
r = typ(r)
except:
ErrorMsg("eTYPEBAD", (cfgfile, linenum, l, str(typ).split()[1][:-1]))
update = False
#####
# Legal Values Enforcement
#####
# These tests valid for everything except booleans.
# An empty LegalVals list means this test is skipped.
# For all numeric types, the test is to see if the new
# value is one of the ones enumerated in LegalVals.
#
# For strings, LegalVals is presumed to contain a list
# of regular expressions. The test is to compile each
# regex and see if any match the new value.
if update and lv:
if typ in (TYPE_COMPLEX, TYPE_FLOAT, TYPE_INT):
if r not in lv:
ErrorMsg("eNOTLEGALVAL", (cfgfile, linenum, r, l))
update = False
elif typ == TYPE_STRING:
foundmatch = False
for rex in lv:
try:
rexc=re.compile(rex)
if rexc.match(r):
foundmatch = True
# This can be kind of complex, so produce
# debug output here to help the poor user
if SymTable.DEBUG:
DebugMsg("dREGEXMATCH", (cfgfile, linenum, r, rex, l))
except:
ErrorMsg("eBADREGEX", (cfgfile, linenum, rex, l))
update = False
if not foundmatch:
ErrorMsg("eNOTLEGALVAL", (cfgfile, linenum, r, l))
update = False
#####
# Bounds Checks
#####
# Check bounds for interger and floats
if update and typ in (TYPE_FLOAT, TYPE_INT):
if low != None and r < low:
ErrorMsg("eVALSMALL", (cfgfile, linenum, r, l, low))
update = False
if up != None and r > up:
ErrorMsg("eVALLARGE", (cfgfile, linenum, r, l, up))
update = False
# Check bounds for strings - these are min/max string lengths, if present
if update and typ == TYPE_STRING:
if low != None and len(r) < low:
ErrorMsg("eSTRINGSHORT", (cfgfile, linenum, r, l, low))
update = False
if up != None and len(r) > up:
ErrorMsg("eSTRINGLONG", (cfgfile, linenum, r, l, up))
update = False
return update
# End of 'ValidateValue()'
#----------------------------------------------------------#
# List Of Public Names Available To Program Importing Us #
#----------------------------------------------------------#
__all__ = ["ParseConfig",
"SymbolTable",
"TYPE_BOOL",
"TYPE_COMPLEX",
"TYPE_FLOAT",
"TYPE_INT",
"TYPE_STRING",
"VarDescriptor"
]
#----------------------------------------------------------#
# Entry Point On Direct Invocation #
#----------------------------------------------------------#
if __name__ == '__main__':
# Print program information
print BANNER
# Print things we know about the environment
pk = Predefined.keys()
pk.sort()
for var in pk:
if var[0] == PREDEFINTRO:
val = Predefined[var]
print "%s%s%s" % (var, (20-len(var)) * " ", val)
tundra