Refactor, creating SpawnBase class

1 files changed, 449 insertions, 0 deletions

diff --git a/pexpect/spawnbase.py b/pexpect/spawnbase.py
new file mode 100644
index 0000000..205c3ff
--- /dev/null
+++ b/pexpect/spawnbase.py
@@ -0,0 +1,449 @@
+import os
+import sys
+import re
+import errno
+from .exceptions import ExceptionPexpect, EOF, TIMEOUT
+from .expect import Expecter, searcher_string, searcher_re
+
+PY3 = (sys.version_info[0] >= 3)
+
+class SpawnBase(object):
+    """A base class providing the backwards-compatible spawn API for Pexpect."""
+    string_type = bytes
+    if PY3:
+        allowed_string_types = (bytes, str)
+        @staticmethod
+        def _chr(c):
+            return bytes([c])
+        linesep = os.linesep.encode('ascii')
+        crlf = '\r\n'.encode('ascii')
+
+        @staticmethod
+        def write_to_stdout(b):
+            try:
+                return sys.stdout.buffer.write(b)
+            except AttributeError:
+                # If stdout has been replaced, it may not have .buffer
+                return sys.stdout.write(b.decode('ascii', 'replace'))
+    else:
+        allowed_string_types = (basestring,)  # analysis:ignore
+        _chr = staticmethod(chr)
+        linesep = os.linesep
+        crlf = '\r\n'
+        write_to_stdout = sys.stdout.write
+
+    encoding = None
+    pid = None
+    flag_eof = False
+
+    def __init__(self, timeout=30, maxread=2000, searchwindowsize=None, logfile=None):
+        self.stdin = sys.stdin
+        self.stdout = sys.stdout
+        self.stderr = sys.stderr
+
+        self.searcher = None
+        self.ignorecase = False
+        self.before = None
+        self.after = None
+        self.match = None
+        self.match_index = None
+        self.terminated = True
+        self.exitstatus = None
+        self.signalstatus = None
+        # status returned by os.waitpid
+        self.status = None
+        # the child file descriptor is initially closed
+        self.child_fd = -1
+        self.timeout = timeout
+        self.delimiter = EOF
+        self.logfile = logfile
+        # input from child (read_nonblocking)
+        self.logfile_read = None
+        # output to send (send, sendline)
+        self.logfile_send = None
+        # max bytes to read at one time into buffer
+        self.maxread = maxread
+        # This is the read buffer. See maxread.
+        self.buffer = self.string_type()
+        # Data before searchwindowsize point is preserved, but not searched.
+        self.searchwindowsize = searchwindowsize
+        # Delay used before sending data to child. Time in seconds.
+        # Most Linux machines don't like this to be below 0.03 (30 ms).
+        self.delaybeforesend = 0.05
+        # Used by close() to give kernel time to update process status.
+        # Time in seconds.
+        self.delayafterclose = 0.1
+        # Used by terminate() to give kernel time to update process status.
+        # Time in seconds.
+        self.delayafterterminate = 0.1
+        self.softspace = False
+        self.name = '<' + repr(self) + '>'
+        self.closed = True
+
+    def _log(self, s, direction):
+        if self.logfile is not None:
+            self.logfile.write(s)
+            self.logfile.flush()
+        second_log = self.logfile_send if (direction=='send') else self.logfile_read
+        if second_log is not None:
+            second_log.write(s)
+            second_log.flush()
+
+    @staticmethod
+    def _coerce_expect_string(s):
+        if not isinstance(s, bytes):
+            return s.encode('ascii')
+        return s
+
+    @staticmethod
+    def _coerce_send_string(s):
+        if not isinstance(s, bytes):
+            return s.encode('utf-8')
+        return s
+
+    @staticmethod
+    def _coerce_read_string(s):
+        return s
+
+    def read_nonblocking(self, size=1, timeout=None):
+        """This reads data from the file descriptor.
+
+        This is a simple implementation suitable for a regular file. Subclasses using ptys or pipes should override it.
+
+        The timeout parameter is ignored.
+        """
+
+        try:
+            s = os.read(self.child_fd, size)
+        except OSError as err:
+            if err.args[0] == errno.EIO:
+                # Linux-style EOF
+                self.flag_eof = True
+                raise EOF('End Of File (EOF). Exception style platform.')
+            raise
+        if s == b'':
+            # BSD-style EOF
+            self.flag_eof = True
+            raise EOF('End Of File (EOF). Empty string style platform.')
+
+        s = self._coerce_read_string(s)
+        self._log(s, 'read')
+        return s
+
+    def _pattern_type_err(self, pattern):
+        raise TypeError('got {badtype} ({badobj!r}) as pattern, must be one'
+                        ' of: {goodtypes}, pexpect.EOF, pexpect.TIMEOUT'\
+                        .format(badtype=type(pattern),
+                                badobj=pattern,
+                                goodtypes=', '.join([str(ast)\
+                                    for ast in self.allowed_string_types])
+                                )
+                        )
+
+    def compile_pattern_list(self, patterns):
+        '''This compiles a pattern-string or a list of pattern-strings.
+        Patterns must be a StringType, EOF, TIMEOUT, SRE_Pattern, or a list of
+        those. Patterns may also be None which results in an empty list (you
+        might do this if waiting for an EOF or TIMEOUT condition without
+        expecting any pattern).
+
+        This is used by expect() when calling expect_list(). Thus expect() is
+        nothing more than::
+
+             cpl = self.compile_pattern_list(pl)
+             return self.expect_list(cpl, timeout)
+
+        If you are using expect() within a loop it may be more
+        efficient to compile the patterns first and then call expect_list().
+        This avoid calls in a loop to compile_pattern_list()::
+
+             cpl = self.compile_pattern_list(my_pattern)
+             while some_condition:
+                ...
+                i = self.expect_list(cpl, timeout)
+                ...
+        '''
+
+        if patterns is None:
+            return []
+        if not isinstance(patterns, list):
+            patterns = [patterns]
+
+        # Allow dot to match \n
+        compile_flags = re.DOTALL
+        if self.ignorecase:
+            compile_flags = compile_flags | re.IGNORECASE
+        compiled_pattern_list = []
+        for idx, p in enumerate(patterns):
+            if isinstance(p, self.allowed_string_types):
+                p = self._coerce_expect_string(p)
+                compiled_pattern_list.append(re.compile(p, compile_flags))
+            elif p is EOF:
+                compiled_pattern_list.append(EOF)
+            elif p is TIMEOUT:
+                compiled_pattern_list.append(TIMEOUT)
+            elif isinstance(p, type(re.compile(''))):
+                compiled_pattern_list.append(p)
+            else:
+                self._pattern_type_err(p)
+        return compiled_pattern_list
+
+    def expect(self, pattern, timeout=-1, searchwindowsize=-1, async=False):
+        '''This seeks through the stream until a pattern is matched. The
+        pattern is overloaded and may take several types. The pattern can be a
+        StringType, EOF, a compiled re, or a list of any of those types.
+        Strings will be compiled to re types. This returns the index into the
+        pattern list. If the pattern was not a list this returns index 0 on a
+        successful match. This may raise exceptions for EOF or TIMEOUT. To
+        avoid the EOF or TIMEOUT exceptions add EOF or TIMEOUT to the pattern
+        list. That will cause expect to match an EOF or TIMEOUT condition
+        instead of raising an exception.
+
+        If you pass a list of patterns and more than one matches, the first
+        match in the stream is chosen. If more than one pattern matches at that
+        point, the leftmost in the pattern list is chosen. For example::
+
+            # the input is 'foobar'
+            index = p.expect(['bar', 'foo', 'foobar'])
+            # returns 1('foo') even though 'foobar' is a "better" match
+
+        Please note, however, that buffering can affect this behavior, since
+        input arrives in unpredictable chunks. For example::
+
+            # the input is 'foobar'
+            index = p.expect(['foobar', 'foo'])
+            # returns 0('foobar') if all input is available at once,
+            # but returs 1('foo') if parts of the final 'bar' arrive late
+
+        After a match is found the instance attributes 'before', 'after' and
+        'match' will be set. You can see all the data read before the match in
+        'before'. You can see the data that was matched in 'after'. The
+        re.MatchObject used in the re match will be in 'match'. If an error
+        occurred then 'before' will be set to all the data read so far and
+        'after' and 'match' will be None.
+
+        If timeout is -1 then timeout will be set to the self.timeout value.
+
+        A list entry may be EOF or TIMEOUT instead of a string. This will
+        catch these exceptions and return the index of the list entry instead
+        of raising the exception. The attribute 'after' will be set to the
+        exception type. The attribute 'match' will be None. This allows you to
+        write code like this::
+
+                index = p.expect(['good', 'bad', pexpect.EOF, pexpect.TIMEOUT])
+                if index == 0:
+                    do_something()
+                elif index == 1:
+                    do_something_else()
+                elif index == 2:
+                    do_some_other_thing()
+                elif index == 3:
+                    do_something_completely_different()
+
+        instead of code like this::
+
+                try:
+                    index = p.expect(['good', 'bad'])
+                    if index == 0:
+                        do_something()
+                    elif index == 1:
+                        do_something_else()
+                except EOF:
+                    do_some_other_thing()
+                except TIMEOUT:
+                    do_something_completely_different()
+
+        These two forms are equivalent. It all depends on what you want. You
+        can also just expect the EOF if you are waiting for all output of a
+        child to finish. For example::
+
+                p = pexpect.spawn('/bin/ls')
+                p.expect(pexpect.EOF)
+                print p.before
+
+        If you are trying to optimize for speed then see expect_list().
+
+        On Python 3.4, or Python 3.3 with asyncio installed, passing
+        ``async=True``  will make this return an :mod:`asyncio` coroutine,
+        which you can yield from to get the same result that this method would
+        normally give directly. So, inside a coroutine, you can replace this code::
+
+            index = p.expect(patterns)
+
+        With this non-blocking form::
+
+            index = yield from p.expect(patterns, async=True)
+        '''
+
+        compiled_pattern_list = self.compile_pattern_list(pattern)
+        return self.expect_list(compiled_pattern_list,
+                timeout, searchwindowsize, async)
+
+    def expect_list(self, pattern_list, timeout=-1, searchwindowsize=-1,
+                    async=False):
+        '''This takes a list of compiled regular expressions and returns the
+        index into the pattern_list that matched the child output. The list may
+        also contain EOF or TIMEOUT(which are not compiled regular
+        expressions). This method is similar to the expect() method except that
+        expect_list() does not recompile the pattern list on every call. This
+        may help if you are trying to optimize for speed, otherwise just use
+        the expect() method.  This is called by expect(). If timeout==-1 then
+        the self.timeout value is used. If searchwindowsize==-1 then the
+        self.searchwindowsize value is used.
+
+        Like :meth:`expect`, passing ``async=True`` will make this return an
+        asyncio coroutine.
+        '''
+        if timeout == -1:
+            timeout = self.timeout
+
+        exp = Expecter(self, searcher_re(pattern_list), searchwindowsize)
+        if async:
+            from .async import expect_async
+            return expect_async(exp, timeout)
+        else:
+            return exp.expect_loop(timeout)
+
+    def expect_exact(self, pattern_list, timeout=-1, searchwindowsize=-1,
+                     async=False):
+
+        '''This is similar to expect(), but uses plain string matching instead
+        of compiled regular expressions in 'pattern_list'. The 'pattern_list'
+        may be a string; a list or other sequence of strings; or TIMEOUT and
+        EOF.
+
+        This call might be faster than expect() for two reasons: string
+        searching is faster than RE matching and it is possible to limit the
+        search to just the end of the input buffer.
+
+        This method is also useful when you don't want to have to worry about
+        escaping regular expression characters that you want to match.
+
+        Like :meth:`expect`, passing ``async=True`` will make this return an
+        asyncio coroutine.
+        '''
+        if timeout == -1:
+            timeout = self.timeout
+
+        if (isinstance(pattern_list, self.allowed_string_types) or
+                pattern_list in (TIMEOUT, EOF)):
+            pattern_list = [pattern_list]
+
+        def prepare_pattern(pattern):
+            if pattern in (TIMEOUT, EOF):
+                return pattern
+            if isinstance(pattern, self.allowed_string_types):
+                return self._coerce_expect_string(pattern)
+            self._pattern_type_err(pattern)
+
+        try:
+            pattern_list = iter(pattern_list)
+        except TypeError:
+            self._pattern_type_err(pattern_list)
+        pattern_list = [prepare_pattern(p) for p in pattern_list]
+
+        exp = Expecter(self, searcher_string(pattern_list), searchwindowsize)
+        if async:
+            from .async import expect_async
+            return expect_async(exp, timeout)
+        else:
+            return exp.expect_loop(timeout)
+
+    def expect_loop(self, searcher, timeout=-1, searchwindowsize=-1):
+        '''This is the common loop used inside expect. The 'searcher' should be
+        an instance of searcher_re or searcher_string, which describes how and
+        what to search for in the input.
+
+        See expect() for other arguments, return value and exceptions. '''
+
+        exp = Expecter(self, searcher, searchwindowsize)
+        return exp.expect_loop(timeout)
+
+    def read(self, size=-1):
+        '''This reads at most "size" bytes from the file (less if the read hits
+        EOF before obtaining size bytes). If the size argument is negative or
+        omitted, read all data until EOF is reached. The bytes are returned as
+        a string object. An empty string is returned when EOF is encountered
+        immediately. '''
+
+        if size == 0:
+            return self.string_type()
+        if size < 0:
+            # delimiter default is EOF
+            self.expect(self.delimiter)
+            return self.before
+
+        # I could have done this more directly by not using expect(), but
+        # I deliberately decided to couple read() to expect() so that
+        # I would catch any bugs early and ensure consistant behavior.
+        # It's a little less efficient, but there is less for me to
+        # worry about if I have to later modify read() or expect().
+        # Note, it's OK if size==-1 in the regex. That just means it
+        # will never match anything in which case we stop only on EOF.
+        cre = re.compile(self._coerce_expect_string('.{%d}' % size), re.DOTALL)
+        # delimiter default is EOF
+        index = self.expect([cre, self.delimiter])
+        if index == 0:
+            ### FIXME self.before should be ''. Should I assert this?
+            return self.after
+        return self.before
+
+    def readline(self, size=-1):
+        '''This reads and returns one entire line. The newline at the end of
+        line is returned as part of the string, unless the file ends without a
+        newline. An empty string is returned if EOF is encountered immediately.
+        This looks for a newline as a CR/LF pair (\\r\\n) even on UNIX because
+        this is what the pseudotty device returns. So contrary to what you may
+        expect you will receive newlines as \\r\\n.
+
+        If the size argument is 0 then an empty string is returned. In all
+        other cases the size argument is ignored, which is not standard
+        behavior for a file-like object. '''
+
+        if size == 0:
+            return self.string_type()
+        # delimiter default is EOF
+        index = self.expect([self.crlf, self.delimiter])
+        if index == 0:
+            return self.before + self.crlf
+        else:
+            return self.before
+
+    def __iter__(self):
+        '''This is to support iterators over a file-like object.
+        '''
+        return iter(self.readline, self.string_type())
+
+    def readlines(self, sizehint=-1):
+        '''This reads until EOF using readline() and returns a list containing
+        the lines thus read. The optional 'sizehint' argument is ignored.
+        Remember, because this reads until EOF that means the child
+        process should have closed its stdout. If you run this method on
+        a child that is still running with its stdout open then this
+        method will block until it timesout.'''
+
+        lines = []
+        while True:
+            line = self.readline()
+            if not line:
+                break
+            lines.append(line)
+        return lines
+
+    def fileno(self):
+        '''Expose file descriptor for a file-like interface
+        '''
+        return self.child_fd
+
+    def flush(self):
+        '''This does nothing. It is here to support the interface for a
+        File-like object. '''
+        pass
+
+    def isatty(self):
+        """Overridden in subclass using tty"""
+        return False
+
+    def kill(self):   # pragma: no cover
+        """Overridden by subclasses with a process to send signals"""
+        pass
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