device/trezor: python2 compatibility - bundle dependencies

src/device_trezor/trezor/tools/README.md

@@ -10,15 +10,29 @@ Install `protoc` for your distribution. Requirements:
 
 
 Soft requirement: Python 3, can be easily installed with [pyenv].
+If Python 3 is used there are no additional python dependencies.
 
-### Python 2
+Since Cmake 3.12 the `FindPython` module is used to locate the Python 
+interpreter in your system. It preferably searches for Python 3, if none
+is found, it searches for Python 2. 
 
-Workaround if there is no Python3 available:
+Lower version of the cmake uses another module which does not guarantee 
+ordering. If you want to override the selected python you can do it in 
+the following way:
 
 ```bash
-pip install backports.tempfile
+export TREZOR_PYTHON=`which python3`
 ``` 
  
+
+### Python 2.7+
+
+Python 3 has `tempfile.TemporaryDirectory` available but Python 2 lacks
+this class so the message generation code uses `backports.tempfile` package
+bundled in the repository.
+
+The minimal Python versions are 2.7 and 3.4
+
 ### Regenerate messages
 
 ```bash

src/device_trezor/trezor/tools/pb2cpp.py

@@ -14,12 +14,18 @@ import hashlib
 try:
     from tempfile import TemporaryDirectory
 except:
-    # Py2 backward compatibility, optionally installed by user
+    # Py2 backward compatibility, using bundled sources.
-    # pip install backports.tempfile
+    # Original source: pip install backports.tempfile
     try:
-        from backports.tempfile import TemporaryDirectory
+        # Try bundled python version
+        import sys
+        sys.path.append(os.path.dirname(__file__))
+        from py2backports.tempfile import TemporaryDirectory
+
     except:
-        raise EnvironmentError('TemporaryDirectory could not be imported. Try: pip install backports.tempfile')
+        raise EnvironmentError('Python 2.7+ or 3.4+ is required. '
+                               'TemporaryDirectory is not available in Python 2.'
+                               'Try to specify python to use, e.g.: "export TREZOR_PYTHON=`which python3`"')
 
 
 AUTO_HEADER = "# Automatically generated by pb2cpp\n"

src/device_trezor/trezor/tools/py2backports/tempfile.py

@@ -0,0 +1,72 @@
+"""
+https://github.com/pjdelport/backports.tempfile/blob/master/src/backports/tempfile.py
+Partial backport of Python 3.5's tempfile module:
+    TemporaryDirectory
+Backport modifications are marked with marked with "XXX backport".
+"""
+from __future__ import absolute_import
+
+import sys
+import warnings as _warnings
+from shutil import rmtree as _rmtree
+
+from py2backports.weakref import finalize
+
+
+# XXX backport:  Rather than backporting all of mkdtemp(), we just create a
+# thin wrapper implementing its Python 3.5 signature.
+if sys.version_info < (3, 5):
+    from tempfile import mkdtemp as old_mkdtemp
+
+    def mkdtemp(suffix=None, prefix=None, dir=None):
+        """
+        Wrap `tempfile.mkdtemp()` to make the suffix and prefix optional (like Python 3.5).
+        """
+        kwargs = {k: v for (k, v) in
+                  dict(suffix=suffix, prefix=prefix, dir=dir).items()
+                  if v is not None}
+        return old_mkdtemp(**kwargs)
+
+else:
+    from tempfile import mkdtemp
+
+
+# XXX backport: ResourceWarning was added in Python 3.2.
+# For earlier versions, fall back to RuntimeWarning instead.
+_ResourceWarning = RuntimeWarning if sys.version_info < (3, 2) else ResourceWarning
+
+
+class TemporaryDirectory(object):
+    """Create and return a temporary directory.  This has the same
+    behavior as mkdtemp but can be used as a context manager.  For
+    example:
+        with TemporaryDirectory() as tmpdir:
+            ...
+    Upon exiting the context, the directory and everything contained
+    in it are removed.
+    """
+
+    def __init__(self, suffix=None, prefix=None, dir=None):
+        self.name = mkdtemp(suffix, prefix, dir)
+        self._finalizer = finalize(
+            self, self._cleanup, self.name,
+            warn_message="Implicitly cleaning up {!r}".format(self))
+
+    @classmethod
+    def _cleanup(cls, name, warn_message):
+        _rmtree(name)
+        _warnings.warn(warn_message, _ResourceWarning)
+
+
+    def __repr__(self):
+        return "<{} {!r}>".format(self.__class__.__name__, self.name)
+
+    def __enter__(self):
+        return self.name
+
+    def __exit__(self, exc, value, tb):
+        self.cleanup()
+
+    def cleanup(self):
+        if self._finalizer.detach():
+            _rmtree(self.name)

src/device_trezor/trezor/tools/py2backports/weakref.py

@@ -0,0 +1,148 @@
+"""
+https://github.com/pjdelport/backports.weakref/blob/master/src/backports/weakref.py
+Partial backport of Python 3.6's weakref module:
+    finalize (new in Python 3.4)
+Backport modifications are marked with "XXX backport".
+"""
+from __future__ import absolute_import
+
+import itertools
+import sys
+from weakref import ref
+
+__all__ = ['finalize']
+
+
+class finalize(object):
+    """Class for finalization of weakrefable objects
+    finalize(obj, func, *args, **kwargs) returns a callable finalizer
+    object which will be called when obj is garbage collected. The
+    first time the finalizer is called it evaluates func(*arg, **kwargs)
+    and returns the result. After this the finalizer is dead, and
+    calling it just returns None.
+    When the program exits any remaining finalizers for which the
+    atexit attribute is true will be run in reverse order of creation.
+    By default atexit is true.
+    """
+
+    # Finalizer objects don't have any state of their own.  They are
+    # just used as keys to lookup _Info objects in the registry.  This
+    # ensures that they cannot be part of a ref-cycle.
+
+    __slots__ = ()
+    _registry = {}
+    _shutdown = False
+    _index_iter = itertools.count()
+    _dirty = False
+    _registered_with_atexit = False
+
+    class _Info(object):
+        __slots__ = ("weakref", "func", "args", "kwargs", "atexit", "index")
+
+    def __init__(self, obj, func, *args, **kwargs):
+        if not self._registered_with_atexit:
+            # We may register the exit function more than once because
+            # of a thread race, but that is harmless
+            import atexit
+            atexit.register(self._exitfunc)
+            finalize._registered_with_atexit = True
+        info = self._Info()
+        info.weakref = ref(obj, self)
+        info.func = func
+        info.args = args
+        info.kwargs = kwargs or None
+        info.atexit = True
+        info.index = next(self._index_iter)
+        self._registry[self] = info
+        finalize._dirty = True
+
+    def __call__(self, _=None):
+        """If alive then mark as dead and return func(*args, **kwargs);
+        otherwise return None"""
+        info = self._registry.pop(self, None)
+        if info and not self._shutdown:
+            return info.func(*info.args, **(info.kwargs or {}))
+
+    def detach(self):
+        """If alive then mark as dead and return (obj, func, args, kwargs);
+        otherwise return None"""
+        info = self._registry.get(self)
+        obj = info and info.weakref()
+        if obj is not None and self._registry.pop(self, None):
+            return (obj, info.func, info.args, info.kwargs or {})
+
+    def peek(self):
+        """If alive then return (obj, func, args, kwargs);
+        otherwise return None"""
+        info = self._registry.get(self)
+        obj = info and info.weakref()
+        if obj is not None:
+            return (obj, info.func, info.args, info.kwargs or {})
+
+    @property
+    def alive(self):
+        """Whether finalizer is alive"""
+        return self in self._registry
+
+    @property
+    def atexit(self):
+        """Whether finalizer should be called at exit"""
+        info = self._registry.get(self)
+        return bool(info) and info.atexit
+
+    @atexit.setter
+    def atexit(self, value):
+        info = self._registry.get(self)
+        if info:
+            info.atexit = bool(value)
+
+    def __repr__(self):
+        info = self._registry.get(self)
+        obj = info and info.weakref()
+        if obj is None:
+            return '<%s object at %#x; dead>' % (type(self).__name__, id(self))
+        else:
+            return '<%s object at %#x; for %r at %#x>' % \
+                   (type(self).__name__, id(self), type(obj).__name__, id(obj))
+
+    @classmethod
+    def _select_for_exit(cls):
+        # Return live finalizers marked for exit, oldest first
+        L = [(f,i) for (f,i) in cls._registry.items() if i.atexit]
+        L.sort(key=lambda item:item[1].index)
+        return [f for (f,i) in L]
+
+    @classmethod
+    def _exitfunc(cls):
+        # At shutdown invoke finalizers for which atexit is true.
+        # This is called once all other non-daemonic threads have been
+        # joined.
+        reenable_gc = False
+        try:
+            if cls._registry:
+                import gc
+                if gc.isenabled():
+                    reenable_gc = True
+                    gc.disable()
+                pending = None
+                while True:
+                    if pending is None or finalize._dirty:
+                        pending = cls._select_for_exit()
+                        finalize._dirty = False
+                    if not pending:
+                        break
+                    f = pending.pop()
+                    try:
+                        # gc is disabled, so (assuming no daemonic
+                        # threads) the following is the only line in
+                        # this function which might trigger creation
+                        # of a new finalizer
+                        f()
+                    except Exception:
+                        sys.excepthook(*sys.exc_info())
+                    assert f not in cls._registry
+        finally:
+            # prevent any more finalizers from executing during shutdown
+            finalize._shutdown = True
+            if reenable_gc:
+                gc.enable()