X-Git-Url: https://arthur.barton.de/gitweb/?a=blobdiff_plain;f=lib%2Fbup%2Fcompat.py;h=00575036e27cc46f7fb6b3408e273831526b9daa;hb=4448f184253125e1b8bd0c55d0098a335d15b90b;hp=6f2e6d233dc532e882771ebf6fe3e1b26e2a86f0;hpb=2fc209306bb7cafab77a482f1a2f88ff263ba93e;p=bup.git

diff --git a/lib/bup/compat.py b/lib/bup/compat.py
index 6f2e6d2..0057503 100644
--- a/lib/bup/compat.py
+++ b/lib/bup/compat.py
@@ -1,36 +1,124 @@
 
 from __future__ import absolute_import, print_function
+from binascii import hexlify
 from traceback import print_exception
-import sys
+import os, sys
 
 # Please see CODINGSTYLE for important exception handling guidelines
-# and the rationale behind add_ex_tb(), chain_ex(), etc.
+# and the rationale behind add_ex_tb(), add_ex_ctx(), etc.
 
 py_maj = sys.version_info[0]
 py3 = py_maj >= 3
 
 if py3:
 
+    # pylint: disable=unused-import
+    from contextlib import ExitStack, nullcontext
+    from os import environb as environ
+    from os import fsdecode, fsencode
     from shlex import quote
+    # pylint: disable=undefined-variable
+    # (for python2 looking here)
+    ModuleNotFoundError = ModuleNotFoundError
+    input = input
     range = range
     str_type = str
+    int_types = (int,)
+
+    def hexstr(b):
+        """Return hex string (not bytes as with hexlify) representation of b."""
+        return b.hex()
+
+    def reraise(ex):
+        raise ex.with_traceback(sys.exc_info()[2])
 
     def add_ex_tb(ex):
         """Do nothing (already handled by Python 3 infrastructure)."""
         return ex
 
-    def chain_ex(ex, context_ex):
+    def add_ex_ctx(ex, context_ex):
         """Do nothing (already handled by Python 3 infrastructure)."""
         return ex
 
+    class pending_raise:
+        """If rethrow is true, rethrow ex (if any), unless the body throws.
+
+        (Supports Python 2 compatibility.)
+
+        """
+        def __init__(self, ex, rethrow=True):
+            self.closed = False
+            self.ex = ex
+            self.rethrow = rethrow
+        def __enter__(self):
+            return None
+        def __exit__(self, exc_type, exc_value, traceback):
+            self.closed = True
+            if not exc_type and self.ex and self.rethrow:
+                raise self.ex
+        def __del__(self):
+            assert self.closed
+
     def items(x):
         return x.items()
 
+    def argv_bytes(x):
+        """Return the original bytes passed to main() for an argv argument."""
+        return fsencode(x)
+
+    def bytes_from_uint(i):
+        return bytes((i,))
+
+    def bytes_from_byte(b):  # python > 2: b[3] returns ord('x'), not b'x'
+        return bytes((b,))
+
+    byte_int = lambda x: x
+
+    def buffer(object, offset=None, size=None):
+        if size:
+            assert offset is not None
+            return memoryview(object)[offset:offset + size]
+        if offset:
+            return memoryview(object)[offset:]
+        return memoryview(object)
+
+    def getcwd():
+        return fsencode(os.getcwd())
+
 else:  # Python 2
 
+    from contextlib import contextmanager
+
+    ModuleNotFoundError = ImportError
+
+    def fsdecode(x):
+        return x
+
+    def fsencode(x):
+        return x
+
     from pipes import quote
+    # pylint: disable=unused-import
+    from os import environ, getcwd
+
+    # pylint: disable=unused-import
+    from bup.py2raise import reraise
+
+    @contextmanager
+    def nullcontext(enter_result=None):
+        yield enter_result
+
+    # on py3 this causes errors, obviously
+    # pylint: disable=undefined-variable
+    input = raw_input
+    # pylint: disable=undefined-variable
     range = xrange
+    # pylint: disable=undefined-variable
     str_type = basestring
+    # pylint: disable=undefined-variable
+    int_types = (int, long)
+
+    hexstr = hexlify
 
     def add_ex_tb(ex):
         """Add a traceback to ex if it doesn't already have one.  Return ex.
@@ -40,9 +128,9 @@ else:  # Python 2
             ex.__traceback__ = sys.exc_info()[2]
         return ex
 
-    def chain_ex(ex, context_ex):
-        """Chain context_ex to ex as the __context__ (unless it already has
-        one).  Return ex.
+    def add_ex_ctx(ex, context_ex):
+        """Make context_ex the __context__ of ex (unless it already has one).
+        Return ex.
 
         """
         if context_ex:
@@ -50,6 +138,34 @@ else:  # Python 2
                 ex.__context__ = context_ex
         return ex
 
+    class pending_raise:
+        """If rethrow is true, rethrow ex (if any), unless the body throws.
+
+        If the body does throw, make any provided ex the __context__
+        of the newer exception (assuming there's no existing
+        __context__).  Ensure the exceptions have __tracebacks__.
+        (Supports Python 2 compatibility.)
+
+        """
+        def __init__(self, ex, rethrow=True):
+            self.closed = False
+            self.ex = ex
+            self.rethrow = rethrow
+        def __enter__(self):
+            if self.ex:
+                add_ex_tb(self.ex)
+        def __exit__(self, exc_type, exc_value, traceback):
+            self.closed = True
+            if exc_value:
+                if self.ex:
+                    add_ex_tb(exc_value)
+                    add_ex_ctx(exc_value, self.ex)
+                return
+            if self.rethrow and self.ex:
+                raise self.ex
+        def __del__(self):
+            assert self.closed
+
     def dump_traceback(ex):
         stack = [ex]
         next_ex = getattr(ex, '__context__', None)
@@ -66,9 +182,68 @@ else:  # Python 2
             tb = getattr(ex, '__traceback__', None)
             print_exception(type(ex), ex, tb)
 
+    class ExitStack:
+        def __init__(self):
+            self.contexts = []
+
+        def __enter__(self):
+            return self
+
+        def __exit__(self, value_type, value, traceback):
+            init_value = value
+            for ctx in reversed(self.contexts):
+                try:
+                    ctx.__exit__(value_type, value, traceback)
+                except BaseException as ex:
+                    add_ex_tb(ex)
+                    if value:
+                        add_ex_ctx(ex, value)
+                    value_type = type(ex)
+                    value = ex
+                    traceback = ex.__traceback__
+            if value is not init_value:
+                raise value
+
+        def enter_context(self, x):
+            self.contexts.append(x)
+
     def items(x):
         return x.iteritems()
 
+    def argv_bytes(x):
+        """Return the original bytes passed to main() for an argv argument."""
+        return x
+
+    bytes_from_uint = chr
+
+    def bytes_from_byte(b):
+        return b
+
+    byte_int = ord
+
+    buffer = buffer
+
+try:
+    import bup_main
+except ModuleNotFoundError:
+    bup_main = None
+
+if bup_main:
+    def get_argvb():
+        "Return a new list containing the current process argv bytes."
+        return bup_main.argv()
+    if py3:
+        def get_argv():
+            "Return a new list containing the current process argv strings."
+            return [x.decode(errors='surrogateescape') for x in bup_main.argv()]
+    else:
+        def get_argv():
+            return bup_main.argv()
+else:
+    def get_argvb():
+        raise Exception('get_argvb requires the bup_main module');
+    def get_argv():
+        raise Exception('get_argv requires the bup_main module');
 
 def wrap_main(main):
     """Run main() and raise a SystemExit with the return value if it
@@ -112,6 +287,6 @@ if __name__ == '__main__':
             try:
                 raise Exception('second')
             except Exception as ex2:
-                raise chain_ex(add_ex_tb(ex2), ex)
+                raise add_ex_ctx(add_ex_tb(ex2), ex)
 
     wrap_main(outer)