'''
Error classes used by Yabs.
'''

import inspect, os, signal, sys, time, traceback

class error( Exception):
    '''Base type for all Yabs errors'''
    def __init__( self):
        Exception.__init__( self)

def signal_name( s):
    for n, v in inspect.getmembers( signal):
       if n.startswith( 'SIG') and s==v:
            return n
    return '<unknown signal>'


def exit_description( e):
    #e = e/256 + (e%256)*256
    if os.WIFSTOPPED( e):
        s = os.WSTOPSIG( e)
        return 'stopped due to signal ' + str( s) + ': ' + signal_name( s)
    elif os.WIFSIGNALED( e):
        s = os.WTERMSIG( e)
        return 'exited due to signal ' + str( s) + ': ' + signal_name( s)
    elif os.WIFEXITED( e):
        return 'exited with code ' + str( os.WEXITSTATUS( e))
    else:
        return 'unrecognised exit status'

class rulefn_error( error):
    '''Errors raised by rule functions'''
    def __init__( self, commandfn, text=None, exc_info=None):
        ''' uses sys.exc_info() if exc_info is None.
        '''
        if exc_info is None:
            exc_info = sys.exc_info()
        error.__init__( self)
        self.commandfn  = commandfn
        self.exc_info   = exc_info
        self.text       = text
        self.text_has_been_printed = False
    def __str__( self):
        # traceback.format_exception doesn't appear to be documented on
        # the python website, but is is the python-2.3 source.
        ret = 'rule-fn failed:\n'
        ret += ''.join( traceback.format_exception( *self.exc_info))
        #if self.text:   ret += 'output was:\n' + self.text
        
        return ret

class command_error( error):
    '''Thrown by yabs.command_* functions'''
    def __init__( self, command, ret, text):
        error.__init__( self)
        #print '************command_error:', command, ret, text
        self.command    = command
        self.ret        = ret
        self.text       = text
        self.text_has_been_printed = False
        self.command_has_been_printed = False
        self.ret_has_been_printed = False
    def __str__( self):
        ret = 'command failed:\n'\
            + '  return value: 0x%x\n' % self.ret\
            + '  command:\n' + str( self.command).strip() + '\n'\
            + '  output:\n' + self.text.strip() + '\n'
        return ret

class commandfn_error( error):
    '''Thrown by yabs.command_* functions'''
    def __init__( self, commandfn, text=None, exc_info=None):
        ''' uses sys.exc_info() if exc_info is None.
        '''
        if exc_info is None:
            exc_info = sys.exc_info()
        error.__init__( self)
        self.commandfn  = commandfn
        self.exc_info   = exc_info
        self.text       = text
        self.text_has_been_printed = False
    def __str__( self):
        # traceback.format_exception doesn't appear to be documented on
        # the python website, but is is the python-2.3 source.
        ret = 'command-fn ' + str( self.commandfn.func_code) + ' failed:\n'
        ret += ''.join( traceback.format_exception( *self.exc_info))
        #if self.text:   ret += 'output was:\n' + self.text
        
        return ret

class file_command_error( error):
    '''Raised when a command fails to create the target.'''
    def __init__( self, filename, command):
        error.__init__( self)
        self.filename = filename
        self.command = command
        self.command_has_been_printed = False
    def __str__( self):
        ret = ''
        ret += 'command failed to create target\n'
        ret += '  filename: ' + self.filename + '\n'
        ret += '  command:  ' + str( self.command) + '\n'
        return ret

class file_command_mtime_error( error):
    '''Raised when a command makes a target older than previously.'''
    def __init__( self, filename, command, original_mtime, new_mtime):
        error.__init__( self)
        self.filename = filename
        self.command = command
        self.original_mtime = original_mtime
        self.new_mtime = new_mtime
        self.command_has_been_printed = False
    def __str__( self):
        ret = 'command created file with older datestamp\n'
        ret += '  filename: ' + self.filename + '\n'
        ret += '  command:  ' + str( self.command) + '\n'
        ret += '  original mtime: ' + time.ctime( self.original_mtime) + '\n'
        ret += '  new mtime:      ' + time.ctime( self.new_mtime) + '\n'
        return ret

class no_rule_error( error):
    '''Raised when no command can be found to make a target.'''
    def __init__( self, filename):
        error.__init__( self)
        self.filename = filename
    def __str__( self):
        return 'don\'t kow how to make: ' + self.filename

class bad_prerequisites( error):
    '''Raised when a rule doesn't return valid prerequisites or semi-
    prerequisites.'''
    def __init__( self, prerequisite):
        error.__init__( self)
        self.prerequisite = prerequisite
    def __str__( self):
        return 'Bad prerequisite or semi-prerequisite: ' + self.prerequisite