[pypy-svn] rev 2432 - pypy/trunk/src/pypy/tool

[sschwarzer at codespeak.net]

Author: sschwarzer
Date: Wed Dec 17 14:19:21 2003
New Revision: 2432

Added:
   pypy/trunk/src/pypy/tool/walk_tree.py   (contents, props changed)
Log:
Make the os.walk function from Python 2.3 also available for environments
with only Python 2.2. The function is accessible under the name "walk"
from this module.


Added: pypy/trunk/src/pypy/tool/walk_tree.py
==============================================================================
--- (empty file)
+++ pypy/trunk/src/pypy/tool/walk_tree.py	Wed Dec 17 14:19:21 2003
@@ -0,0 +1,95 @@
+import os
+
+# this is copied from os.py in Python 2.3; use it only below if the
+# native walk function isn't available
+def _walk(top, topdown=True, onerror=None):
+    """Directory tree generator.
+
+    For each directory in the directory tree rooted at top (including top
+    itself, but excluding '.' and '..'), yields a 3-tuple
+
+        dirpath, dirnames, filenames
+
+    dirpath is a string, the path to the directory.  dirnames is a list of
+    the names of the subdirectories in dirpath (excluding '.' and '..').
+    filenames is a list of the names of the non-directory files in dirpath.
+    Note that the names in the lists are just names, with no path components.
+    To get a full path (which begins with top) to a file or directory in
+    dirpath, do os.path.join(dirpath, name).
+
+    If optional arg 'topdown' is true or not specified, the triple for a
+    directory is generated before the triples for any of its subdirectories
+    (directories are generated top down).  If topdown is false, the triple
+    for a directory is generated after the triples for all of its
+    subdirectories (directories are generated bottom up).
+
+    When topdown is true, the caller can modify the dirnames list in-place
+    (e.g., via del or slice assignment), and walk will only recurse into the
+    subdirectories whose names remain in dirnames; this can be used to prune
+    the search, or to impose a specific order of visiting.  Modifying
+    dirnames when topdown is false is ineffective, since the directories in
+    dirnames have already been generated by the time dirnames itself is
+    generated.
+
+    By default errors from the os.listdir() call are ignored.  If
+    optional arg 'onerror' is specified, it should be a function; it
+    will be called with one argument, an os.error instance.  It can
+    report the error to continue with the walk, or raise the exception
+    to abort the walk.  Note that the filename is available as the
+    filename attribute of the exception object.
+
+    Caution:  if you pass a relative pathname for top, don't change the
+    current working directory between resumptions of walk.  walk never
+    changes the current directory, and assumes that the client doesn't
+    either.
+
+    Example:
+
+    from os.path import join, getsize
+    for root, dirs, files in walk('python/Lib/email'):
+        print root, "consumes",
+        print sum([getsize(join(root, name)) for name in files]),
+        print "bytes in", len(files), "non-directory files"
+        if 'CVS' in dirs:
+            dirs.remove('CVS')  # don't visit CVS directories
+    """
+
+    from os.path import join, isdir, islink
+
+    # We may not have read permission for top, in which case we can't
+    # get a list of the files the directory contains.  os.path.walk
+    # always suppressed the exception then, rather than blow up for a
+    # minor reason when (say) a thousand readable directories are still
+    # left to visit.  That logic is copied here.
+    try:
+        # Note that listdir and error are globals in this module due
+        # to earlier import-*.
+        names = listdir(top)
+    except error, err:
+        if onerror is not None:
+            onerror(err)
+        return
+
+    dirs, nondirs = [], []
+    for name in names:
+        if isdir(join(top, name)):
+            dirs.append(name)
+        else:
+            nondirs.append(name)
+
+    if topdown:
+        yield top, dirs, nondirs
+    for name in dirs:
+        path = join(top, name)
+        if not islink(path):
+            for x in walk(path, topdown, onerror):
+                yield x
+    if not topdown:
+        yield top, dirs, nondirs
+
+
+try:
+    walk = os.walk
+except AttributeError:
+    walk = _walk
+