parse_excludes: drop empty --exclude-from paths

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

diff --git a/lib/bup/helpers.py b/lib/bup/helpers.py
index 4943d70ccc6c748a157c871757848e99a478ac01..b55c4a981b4cf462e267b88a5192559c02dc72b5 100644 (file)
--- a/lib/bup/helpers.py
+++ b/lib/bup/helpers.py
@@ -1,8 +1,11 @@
 """Helper functions and classes for bup."""
 
+from ctypes import sizeof, c_void_p
+from os import environ
 import sys, os, pwd, subprocess, errno, socket, select, mmap, stat, re, struct
 import hashlib, heapq, operator, time, grp
-from bup import _version, _helpers
+
+from bup import _helpers
 import bup._helpers as _helpers
 import math
 
@@ -126,6 +129,25 @@ def mkdirp(d, mode=None):
             raise
 
 
+_unspecified_next_default = object()
+
+def _fallback_next(it, default=_unspecified_next_default):
+    """Retrieve the next item from the iterator by calling its
+    next() method. If default is given, it is returned if the
+    iterator is exhausted, otherwise StopIteration is raised."""
+
+    if default is _unspecified_next_default:
+        return it.next()
+    else:
+        try:
+            return it.next()
+        except StopIteration:
+            return default
+
+if sys.version_info < (2, 6):
+    next =  _fallback_next
+
+
 def merge_iter(iters, pfreq, pfunc, pfinal, key=None):
     if key:
         samekey = lambda e, pe: getattr(e, key) == getattr(pe, key, None)
@@ -169,9 +191,9 @@ def unlink(f):
             pass  # it doesn't exist, that's what you asked for
 
 
-def readpipe(argv):
+def readpipe(argv, preexec_fn=None):
     """Run a subprocess and return its output."""
-    p = subprocess.Popen(argv, stdout=subprocess.PIPE)
+    p = subprocess.Popen(argv, stdout=subprocess.PIPE, preexec_fn=preexec_fn)
     out, err = p.communicate()
     if p.returncode != 0:
         raise Exception('subprocess %r failed with status %d'
@@ -179,6 +201,41 @@ def readpipe(argv):
     return out
 
 
+def _argmax_base(command):
+    base_size = 2048
+    for c in command:
+        base_size += len(command) + 1
+    for k, v in environ.iteritems():
+        base_size += len(k) + len(v) + 2 + sizeof(c_void_p)
+    return base_size
+
+
+def _argmax_args_size(args):
+    return sum(len(x) + 1 + sizeof(c_void_p) for x in args)
+
+
+def batchpipe(command, args, preexec_fn=None, arg_max=_helpers.SC_ARG_MAX):
+    """If args is not empty, yield the output produced by calling the
+command list with args as a sequence of strings (It may be necessary
+to return multiple strings in order to respect ARG_MAX)."""
+    # The optional arg_max arg is a workaround for an issue with the
+    # current wvtest behavior.
+    base_size = _argmax_base(command)
+    while args:
+        room = arg_max - base_size
+        i = 0
+        while i < len(args):
+            next_size = _argmax_args_size(args[i:i+1])
+            if room - next_size < 0:
+                break
+            room -= next_size
+            i += 1
+        sub_args = args[:i]
+        args = args[i:]
+        assert(len(sub_args))
+        yield readpipe(command + sub_args, preexec_fn=preexec_fn)
+
+
 def realpath(p):
     """Get the absolute path of a file.
 
@@ -755,7 +812,10 @@ def parse_excludes(options, fatal):
             except IOError, e:
                 raise fatal("couldn't read %s" % parameter)
             for exclude_path in f.readlines():
-                excluded_paths.append(realpath(exclude_path.strip()))
+                # FIXME: perhaps this should be rstrip('\n')
+                exclude_path = realpath(exclude_path.strip())
+                if exclude_path:
+                    excluded_paths.append(exclude_path)
     return sorted(frozenset(excluded_paths))
 
 
@@ -778,6 +838,8 @@ def parse_rx_excludes(options, fatal):
                 raise fatal("couldn't read %s" % parameter)
             for pattern in f.readlines():
                 spattern = pattern.rstrip('\n')
+                if not spattern:
+                    continue
                 try:
                     excluded_patterns.append(re.compile(spattern))
                 except re.error, ex:
@@ -887,30 +949,3 @@ def grafted_path_components(graft_points, path):
     return path_components(clean_path)
 
 Sha1 = hashlib.sha1
-
-def version_date():
-    """Format bup's version date string for output."""
-    return _version.DATE.split(' ')[0]
-
-
-def version_commit():
-    """Get the commit hash of bup's current version."""
-    return _version.COMMIT
-
-
-def version_tag():
-    """Format bup's version tag (the official version number).
-
-    When generated from a commit other than one pointed to with a tag, the
-    returned string will be "unknown-" followed by the first seven positions of
-    the commit hash.
-    """
-    names = _version.NAMES.strip()
-    assert(names[0] == '(')
-    assert(names[-1] == ')')
-    names = names[1:-1]
-    l = [n.strip() for n in names.split(',')]
-    for n in l:
-        if n.startswith('tag: bup-'):
-            return n[9:]
-    return 'unknown-%s' % _version.COMMIT[:7]