helpers: rename realpath to resolve_parent

[bup.git] / lib / bup / helpers.py

diff --git a/lib/bup/helpers.py b/lib/bup/helpers.py
index 3427e0397fe4e86cb31ed4949ad7aea951582bca..b052b63021511b035a94ac9945e01dce1099637d 100644 (file)
--- a/lib/bup/helpers.py
+++ b/lib/bup/helpers.py
@@ -41,11 +41,15 @@ def atof(s):
 buglvl = atoi(os.environ.get('BUP_DEBUG', 0))
 
 
-# If the platform doesn't have fdatasync (OS X), fall back to fsync.
-try:
-    fdatasync = os.fdatasync
-except AttributeError:
-    fdatasync = os.fsync
+if sys.platform.startswith('darwin'):
+    # Apparently fsync on OS X doesn't guarantee to sync all the way down
+    import fcntl
+    fdatasync = lambda fd : fcntl.fcntl(fd, fcntl.F_FULLFSYNC)
+else: # If the platform doesn't have fdatasync, fall back to fsync
+    try:
+        fdatasync = os.fdatasync
+    except AttributeError:
+        fdatasync = os.fsync
 
 
 # Write (blockingly) to sockets that may or may not be in blocking mode.
@@ -59,7 +63,7 @@ def _hard_write(fd, buf):
             raise IOError('select(fd) returned without being writable')
         try:
             sz = os.write(fd, buf)
-        except OSError, e:
+        except OSError as e:
             if e.errno != errno.EAGAIN:
                 raise
         assert(sz >= 0)
@@ -129,7 +133,7 @@ def mkdirp(d, mode=None):
             os.makedirs(d, mode)
         else:
             os.makedirs(d)
-    except OSError, e:
+    except OSError as e:
         if e.errno == errno.EEXIST:
             pass
         else:
@@ -193,7 +197,7 @@ def unlink(f):
     """
     try:
         os.unlink(f)
-    except OSError, e:
+    except OSError as e:
         if e.errno != errno.ENOENT:
             raise
 
@@ -243,8 +247,8 @@ to return multiple strings in order to respect ARG_MAX)."""
         yield readpipe(command + sub_args, preexec_fn=preexec_fn)
 
 
-def realpath(p):
-    """Get the absolute path of a file.
+def resolve_parent(p):
+    """Return the absolute path of a file without following any final symlink.
 
     Behaves like os.path.realpath, but doesn't follow a symlink for the last
     element. (ie. if 'p' itself is a symlink, this one won't follow it, but it
@@ -735,7 +739,8 @@ if _mincore:
 
     def fmincore(fd):
         """Return the mincore() data for fd as a bytearray whose values can be
-        tested via MINCORE_INCORE"""
+        tested via MINCORE_INCORE, or None if fd does not fully
+        support the operation."""
         st = os.fstat(fd)
         if (st.st_size == 0):
             return bytearray(0)
@@ -750,7 +755,13 @@ if _mincore:
         for ci in xrange(chunk_count):
             pos = _fmincore_chunk_size * ci;
             msize = min(_fmincore_chunk_size, st.st_size - pos)
-            m = mmap.mmap(fd, msize, mmap.MAP_PRIVATE, 0, 0, pos)
+            try:
+                m = mmap.mmap(fd, msize, mmap.MAP_PRIVATE, 0, 0, pos)
+            except mmap.error as ex:
+                if ex.errno == errno.EINVAL or ex.errno == errno.ENODEV:
+                    # Perhaps the file was a pipe, i.e. "... | bup split ..."
+                    return None
+                raise ex
             _mincore(m, msize, 0, result, ci * pages_per_chunk);
         return result
 
@@ -871,7 +882,7 @@ def parse_date_or_fatal(str, fatal):
     For now we expect a string that contains a float."""
     try:
         date = float(str)
-    except ValueError, e:
+    except ValueError as e:
         raise fatal('invalid date format (should be a float): %r' % e)
     else:
         return date
@@ -884,15 +895,15 @@ def parse_excludes(options, fatal):
     for flag in options:
         (option, parameter) = flag
         if option == '--exclude':
-            excluded_paths.append(realpath(parameter))
+            excluded_paths.append(resolve_parent(parameter))
         elif option == '--exclude-from':
             try:
-                f = open(realpath(parameter))
-            except IOError, e:
+                f = open(resolve_parent(parameter))
+            except IOError as e:
                 raise fatal("couldn't read %s" % parameter)
             for exclude_path in f.readlines():
                 # FIXME: perhaps this should be rstrip('\n')
-                exclude_path = realpath(exclude_path.strip())
+                exclude_path = resolve_parent(exclude_path.strip())
                 if exclude_path:
                     excluded_paths.append(exclude_path)
     return sorted(frozenset(excluded_paths))
@@ -908,12 +919,12 @@ def parse_rx_excludes(options, fatal):
         if option == '--exclude-rx':
             try:
                 excluded_patterns.append(re.compile(parameter))
-            except re.error, ex:
+            except re.error as ex:
                 fatal('invalid --exclude-rx pattern (%s): %s' % (parameter, ex))
         elif option == '--exclude-rx-from':
             try:
-                f = open(realpath(parameter))
-            except IOError, e:
+                f = open(resolve_parent(parameter))
+            except IOError as e:
                 raise fatal("couldn't read %s" % parameter)
             for pattern in f.readlines():
                 spattern = pattern.rstrip('\n')
@@ -921,7 +932,7 @@ def parse_rx_excludes(options, fatal):
                     continue
                 try:
                     excluded_patterns.append(re.compile(spattern))
-                except re.error, ex:
+                except re.error as ex:
                     fatal('invalid --exclude-rx pattern (%s): %s' % (spattern, ex))
     return excluded_patterns