diff options
Diffstat (limited to 'lib/spack/llnl/util/link_tree.py')
| -rw-r--r-- | lib/spack/llnl/util/link_tree.py | 197 |
1 files changed, 112 insertions, 85 deletions
diff --git a/lib/spack/llnl/util/link_tree.py b/lib/spack/llnl/util/link_tree.py index 2d7126be2c..887f6f4d26 100644 --- a/lib/spack/llnl/util/link_tree.py +++ b/lib/spack/llnl/util/link_tree.py @@ -29,108 +29,116 @@ import os import shutil from llnl.util.filesystem import mkdirp +empty_file_name = '.spack-empty' -class LinkTree(object): - """Class to create trees of symbolic links from a source directory. - LinkTree objects are constructed with a source root. Their - methods allow you to create and delete trees of symbolic links - back to the source tree in specific destination directories. - Trees comprise symlinks only to files; directries are never - symlinked to, to prevent the source directory from ever being - modified. +def traverse_tree(source_root, dest_root, rel_path='', **kwargs): + """Traverse two filesystem trees simultaneously. + + Walks the LinkTree directory in pre or post order. Yields each + file in the source directory with a matching path from the dest + directory, along with whether the file is a directory. + e.g., for this tree:: + + root/ + a/ + file1 + file2 + b/ + file3 + + When called on dest, this yields:: + + ('root', 'dest') + ('root/a', 'dest/a') + ('root/a/file1', 'dest/a/file1') + ('root/a/file2', 'dest/a/file2') + ('root/b', 'dest/b') + ('root/b/file3', 'dest/b/file3') + + Optional args: + + order=[pre|post] -- Whether to do pre- or post-order traveral. + + ignore=<predicate> -- Predicate indicating which files to ignore. + + follow_nonexisting -- Whether to descend into directories in + src that do not exit in dest. Default True. + + follow_links -- Whether to descend into symlinks in src. """ - def __init__(self, source_root): - self._root = source_root + follow_nonexisting = kwargs.get('follow_nonexisting', True) + follow_links = kwargs.get('follow_link', False) + # Yield in pre or post order? + order = kwargs.get('order', 'pre') + if order not in ('pre', 'post'): + raise ValueError("Order must be 'pre' or 'post'.") - def traverse(self, dest_root, **kwargs): - """Traverse LinkTree root and dest simultaneously. + # List of relative paths to ignore under the src root. + ignore = kwargs.get('ignore', lambda filename: False) - Walks the LinkTree directory in pre or post order. Yields - each file in the source directory with a matching path from - the dest directory. e.g., for this tree:: + # Don't descend into ignored directories + if ignore(rel_path): + return - root/ - a/ - file1 - file2 - b/ - file3 + source_path = os.path.join(source_root, rel_path) + dest_path = os.path.join(dest_root, rel_path) - When called on dest, this yields:: + # preorder yields directories before children + if order == 'pre': + yield (source_path, dest_path) - ('root', 'dest') - ('root/a', 'dest/a') - ('root/a/file1', 'dest/a/file1') - ('root/a/file2', 'dest/a/file2') - ('root/b', 'dest/b') - ('root/b/file3', 'dest/b/file3') + for f in os.listdir(source_path): + source_child = os.path.join(source_path, f) + dest_child = os.path.join(dest_path, f) - Optional args: + # Treat as a directory + if os.path.isdir(source_child) and ( + follow_links or not os.path.islink(source_child)): - order=[pre|post] -- Whether to do pre- or post-order traveral. + # When follow_nonexisting isn't set, don't descend into dirs + # in source that do not exist in dest + if follow_nonexisting or os.path.exists(dest_child): + tuples = traverse_tree(source_child, dest_child, rel_path, **kwargs) + for t in tuples: yield t - ignore=<predicate> -- Predicate indicating which files to ignore. + # Treat as a file. + elif not ignore(os.path.join(rel_path, f)): + yield (source_child, dest_child) + + if order == 'post': + yield (source_path, dest_path) - follow_nonexisting -- Whether to descend into directories in - src that do not exit in dest. - """ - # Yield directories before or after their contents. - order = kwargs.get('order', 'pre') - if order not in ('pre', 'post'): - raise ValueError("Order must be 'pre' or 'post'.") - - # List of relative paths to ignore under the src root. - ignore = kwargs.get('ignore', lambda filename: False) - - # Whether to descend when dirs dont' exist in dest. - follow_nonexisting = kwargs.get('follow_nonexisting', True) - - for dirpath, dirnames, filenames in os.walk(self._root): - rel_path = dirpath[len(self._root):] - rel_path = rel_path.lstrip(os.path.sep) - dest_dirpath = os.path.join(dest_root, rel_path) - - # Don't descend into ignored directories - if ignore(dest_dirpath): - return - - # Don't descend into dirs in dest that do not exist in src. - if not follow_nonexisting: - dirnames[:] = [ - d for d in dirnames - if os.path.exists(os.path.join(dest_dirpath, d))] - - # preorder yields directories before children - if order == 'pre': - yield (dirpath, dest_dirpath) - - for name in filenames: - src_file = os.path.join(dirpath, name) - dest_file = os.path.join(dest_dirpath, name) - - # Ignore particular paths inside the install root. - src_relpath = src_file[len(self._root):] - src_relpath = src_relpath.lstrip(os.path.sep) - if ignore(src_relpath): - continue - yield (src_file, dest_file) +class LinkTree(object): + """Class to create trees of symbolic links from a source directory. - # postorder yields directories after children - if order == 'post': - yield (dirpath, dest_dirpath) + LinkTree objects are constructed with a source root. Their + methods allow you to create and delete trees of symbolic links + back to the source tree in specific destination directories. + Trees comprise symlinks only to files; directries are never + symlinked to, to prevent the source directory from ever being + modified. + + """ + def __init__(self, source_root): + if not os.path.exists(source_root): + raise IOError("No such file or directory: '%s'", source_root) + self._root = source_root def find_conflict(self, dest_root, **kwargs): - """Returns the first file in dest that also exists in src.""" + """Returns the first file in dest that conflicts with src""" kwargs['follow_nonexisting'] = False - for src, dest in self.traverse(dest_root, **kwargs): - if os.path.exists(dest) and not os.path.isdir(dest): + for src, dest in traverse_tree(self._root, dest_root, **kwargs): + if os.path.isdir(src): + if os.path.exists(dest) and not os.path.isdir(dest): + return dest + elif os.path.exists(dest): return dest return None @@ -138,9 +146,20 @@ class LinkTree(object): def merge(self, dest_root, **kwargs): """Link all files in src into dest, creating directories if necessary.""" kwargs['order'] = 'pre' - for src, dest in self.traverse(dest_root, **kwargs): + for src, dest in traverse_tree(self._root, dest_root, **kwargs): if os.path.isdir(src): - mkdirp(dest) + if not os.path.exists(dest): + mkdirp(dest) + continue + + if not os.path.isdir(dest): + raise ValueError("File blocks directory: %s" % dest) + + # mark empty directories so they aren't removed on unmerge. + if not os.listdir(dest): + marker = os.path.join(dest, empty_file_name) + touch(marker) + else: assert(not os.path.exists(dest)) os.symlink(src, dest) @@ -153,12 +172,20 @@ class LinkTree(object): """ kwargs['order'] = 'post' - for src, dest in self.traverse(dest_root, **kwargs): - if os.path.isdir(dest): + for src, dest in traverse_tree(self._root, dest_root, **kwargs): + if os.path.isdir(src): + if not os.path.isdir(dest): + raise ValueError("File blocks directory: %s" % dest) + + # remove directory if it is empty. if not os.listdir(dest): - # TODO: what if empty directories were present pre-merge? shutil.rmtree(dest, ignore_errors=True) + # remove empty dir marker if present. + marker = os.path.join(dest, empty_file_name) + if os.path.exists(marker): + os.remove(marker) + elif os.path.exists(dest): if not os.path.islink(dest): raise ValueError("%s is not a link tree!" % dest) |