import os import sys import py import tempfile try: from io import StringIO except ImportError: from StringIO import StringIO if sys.version_info < (3,0): class TextIO(StringIO): def write(self, data): if not isinstance(data, unicode): data = unicode(data, getattr(self, '_encoding', 'UTF-8'), 'replace') StringIO.write(self, data) else: TextIO = StringIO try: from io import BytesIO except ImportError: class BytesIO(StringIO): def write(self, data): if isinstance(data, unicode): raise TypeError("not a byte value: %r" %(data,)) StringIO.write(self, data) patchsysdict = {0: 'stdin', 1: 'stdout', 2: 'stderr'} class FDCapture: """ Capture IO to/from a given os-level filedescriptor. """ def __init__(self, targetfd, tmpfile=None, now=True, patchsys=False): """ save targetfd descriptor, and open a new temporary file there. If no tmpfile is specified a tempfile.Tempfile() will be opened in text mode. """ self.targetfd = targetfd if tmpfile is None and targetfd != 0: f = tempfile.TemporaryFile('wb+') tmpfile = dupfile(f, encoding="UTF-8") f.close() self.tmpfile = tmpfile self._savefd = os.dup(self.targetfd) if patchsys: self._oldsys = getattr(sys, patchsysdict[targetfd]) if now: self.start() def start(self): try: os.fstat(self._savefd) except OSError: raise ValueError("saved filedescriptor not valid, " "did you call start() twice?") if self.targetfd == 0 and not self.tmpfile: fd = os.open(devnullpath, os.O_RDONLY) os.dup2(fd, 0) os.close(fd) if hasattr(self, '_oldsys'): setattr(sys, patchsysdict[self.targetfd], DontReadFromInput()) else: os.dup2(self.tmpfile.fileno(), self.targetfd) if hasattr(self, '_oldsys'): setattr(sys, patchsysdict[self.targetfd], self.tmpfile) def done(self): """ unpatch and clean up, returns the self.tmpfile (file object) """ os.dup2(self._savefd, self.targetfd) os.close(self._savefd) if self.targetfd != 0: self.tmpfile.seek(0) if hasattr(self, '_oldsys'): setattr(sys, patchsysdict[self.targetfd], self._oldsys) return self.tmpfile def writeorg(self, data): """ write a string to the original file descriptor """ tempfp = tempfile.TemporaryFile() try: os.dup2(self._savefd, tempfp.fileno()) tempfp.write(data) finally: tempfp.close() def dupfile(f, mode=None, buffering=0, raising=False, encoding=None): """ return a new open file object that's a duplicate of f mode is duplicated if not given, 'buffering' controls buffer size (defaulting to no buffering) and 'raising' defines whether an exception is raised when an incompatible file object is passed in (if raising is False, the file object itself will be returned) """ try: fd = f.fileno() mode = mode or f.mode except AttributeError: if raising: raise return f newfd = os.dup(fd) if sys.version_info >= (3,0): if encoding is not None: mode = mode.replace("b", "") buffering = True return os.fdopen(newfd, mode, buffering, encoding, closefd=True) else: f = os.fdopen(newfd, mode, buffering) if encoding is not None: return EncodedFile(f, encoding) return f class EncodedFile(object): def __init__(self, _stream, encoding): self._stream = _stream self.encoding = encoding def write(self, obj): if isinstance(obj, unicode): obj = obj.encode(self.encoding) elif isinstance(obj, str): pass else: obj = str(obj) self._stream.write(obj) def writelines(self, linelist): data = ''.join(linelist) self.write(data) def __getattr__(self, name): return getattr(self._stream, name) class Capture(object): def call(cls, func, *args, **kwargs): """ return a (res, out, err) tuple where out and err represent the output/error output during function execution. call the given function with args/kwargs and capture output/error during its execution. """ so = cls() try: res = func(*args, **kwargs) finally: out, err = so.reset() return res, out, err call = classmethod(call) def reset(self): """ reset sys.stdout/stderr and return captured output as strings. """ if hasattr(self, '_reset'): raise ValueError("was already reset") self._reset = True outfile, errfile = self.done(save=False) out, err = "", "" if outfile and not outfile.closed: out = outfile.read() outfile.close() if errfile and errfile != outfile and not errfile.closed: err = errfile.read() errfile.close() return out, err def suspend(self): """ return current snapshot captures, memorize tempfiles. """ outerr = self.readouterr() outfile, errfile = self.done() return outerr class StdCaptureFD(Capture): """ This class allows to capture writes to FD1 and FD2 and may connect a NULL file to FD0 (and prevent reads from sys.stdin). If any of the 0,1,2 file descriptors is invalid it will not be captured. """ def __init__(self, out=True, err=True, mixed=False, in_=True, patchsys=True, now=True): self._options = { "out": out, "err": err, "mixed": mixed, "in_": in_, "patchsys": patchsys, "now": now, } self._save() if now: self.startall() def _save(self): in_ = self._options['in_'] out = self._options['out'] err = self._options['err'] mixed = self._options['mixed'] patchsys = self._options['patchsys'] if in_: try: self.in_ = FDCapture(0, tmpfile=None, now=False, patchsys=patchsys) except OSError: pass if out: tmpfile = None if hasattr(out, 'write'): tmpfile = out try: self.out = FDCapture(1, tmpfile=tmpfile, now=False, patchsys=patchsys) self._options['out'] = self.out.tmpfile except OSError: pass if err: if out and mixed: tmpfile = self.out.tmpfile elif hasattr(err, 'write'): tmpfile = err else: tmpfile = None try: self.err = FDCapture(2, tmpfile=tmpfile, now=False, patchsys=patchsys) self._options['err'] = self.err.tmpfile except OSError: pass def startall(self): if hasattr(self, 'in_'): self.in_.start() if hasattr(self, 'out'): self.out.start() if hasattr(self, 'err'): self.err.start() def resume(self): """ resume capturing with original temp files. """ self.startall() def done(self, save=True): """ return (outfile, errfile) and stop capturing. """ outfile = errfile = None if hasattr(self, 'out') and not self.out.tmpfile.closed: outfile = self.out.done() if hasattr(self, 'err') and not self.err.tmpfile.closed: errfile = self.err.done() if hasattr(self, 'in_'): tmpfile = self.in_.done() if save: self._save() return outfile, errfile def readouterr(self): """ return snapshot value of stdout/stderr capturings. """ if hasattr(self, "out"): out = self._readsnapshot(self.out.tmpfile) else: out = "" if hasattr(self, "err"): err = self._readsnapshot(self.err.tmpfile) else: err = "" return [out, err] def _readsnapshot(self, f): f.seek(0) res = f.read() enc = getattr(f, "encoding", None) if enc: res = py.builtin._totext(res, enc, "replace") f.truncate(0) f.seek(0) return res class StdCapture(Capture): """ This class allows to capture writes to sys.stdout|stderr "in-memory" and will raise errors on tries to read from sys.stdin. It only modifies sys.stdout|stderr|stdin attributes and does not touch underlying File Descriptors (use StdCaptureFD for that). """ def __init__(self, out=True, err=True, in_=True, mixed=False, now=True): self._oldout = sys.stdout self._olderr = sys.stderr self._oldin = sys.stdin if out and not hasattr(out, 'file'): out = TextIO() self.out = out if err: if mixed: err = out elif not hasattr(err, 'write'): err = TextIO() self.err = err self.in_ = in_ if now: self.startall() def startall(self): if self.out: sys.stdout = self.out if self.err: sys.stderr = self.err if self.in_: sys.stdin = self.in_ = DontReadFromInput() def done(self, save=True): """ return (outfile, errfile) and stop capturing. """ outfile = errfile = None if self.out and not self.out.closed: sys.stdout = self._oldout outfile = self.out outfile.seek(0) if self.err and not self.err.closed: sys.stderr = self._olderr errfile = self.err errfile.seek(0) if self.in_: sys.stdin = self._oldin return outfile, errfile def resume(self): """ resume capturing with original temp files. """ self.startall() def readouterr(self): """ return snapshot value of stdout/stderr capturings. """ out = err = "" if self.out: out = self.out.getvalue() self.out.truncate(0) self.out.seek(0) if self.err: err = self.err.getvalue() self.err.truncate(0) self.err.seek(0) return out, err class DontReadFromInput: """Temporary stub class. Ideally when stdin is accessed, the capturing should be turned off, with possibly all data captured so far sent to the screen. This should be configurable, though, because in automated test runs it is better to crash than hang indefinitely. """ def read(self, *args): raise IOError("reading from stdin while output is captured") readline = read readlines = read __iter__ = read def fileno(self): raise ValueError("redirected Stdin is pseudofile, has no fileno()") def isatty(self): return False def close(self): pass try: devnullpath = os.devnull except AttributeError: if os.name == 'nt': devnullpath = 'NUL' else: devnullpath = '/dev/null'