move file walker into its own module

3 files changed, 36 insertions, 17 deletions

diff --git a/bsie/apps/index.py b/bsie/apps/index.py
index ef467bd..7dda6f4 100644
--- a/bsie/apps/index.py
+++ b/bsie/apps/index.py
@@ -6,7 +6,7 @@ import typing
 
 # bsie imports
 from bsie.lib import BSIE, DefaultNamingPolicy
-from bsie.utils import bsfs, errors, node as node_
+from bsie.utils import bsfs, errors, node as node_, list_files
 
 # inner-module imports
 from . import _loader
@@ -59,22 +59,9 @@ def main(argv):
         # FIXME: simplify code (below but maybe also above)
         # FIXME: How to handle dependencies between data?
         #        E.g. do I still want to link to a tag despite not being permitted to set its label?
-
-        # index input paths
-        for path in args.input_file:
-            if not os.path.exists(path):
-                pass # FIXME: notify the user
-            elif os.path.isdir(path) and args.recursive:
-                for dirpath, _, filenames in os.walk(path, topdown=True, followlinks=args.follow):
-                    for filename in filenames:
-                        for node, pred, value in bsie.from_file(os.path.join(dirpath, filename)):
-                            handle(node, pred, value)
-            elif os.path.isfile(path):
-                for node, pred, value in bsie.from_file(path):
-                    handle(node, pred, value)
-            else:
-                raise errors.UnreachableError()
-
+        for path in list_files(args.input_file, args.recursive, args.follow):
+            for node, pred, value in bsie.from_file(path):
+                handle(node, pred, value)
 
     if args.print:
         walk(print)
diff --git a/bsie/utils/__init__.py b/bsie/utils/__init__.py
index 18c8db7..4f08604 100644
--- a/bsie/utils/__init__.py
+++ b/bsie/utils/__init__.py
@@ -8,6 +8,7 @@ from . import bsfs
 from . import filematcher
 from . import namespaces as ns
 from . import node
+from .filewalker import list_files
 from .loading import safe_load, unpack_qualified_name
 
 # exports
diff --git a/bsie/utils/filewalker.py b/bsie/utils/filewalker.py
new file mode 100644
index 0000000..3c36926
--- /dev/null
+++ b/bsie/utils/filewalker.py
@@ -0,0 +1,31 @@
+
+# standard imports
+import os
+import typing
+
+# exports
+__all__: typing.Sequence[str] = (
+    'list_files',
+    )
+
+
+## code ##
+
+def list_files(
+        roots: typing.Iterable[str],
+        recursive: bool = True,
+        follow_symlinks: bool = True,
+        ) -> typing.Iterator[str]:
+    """Iterate over all files in *roots*, recursively by default."""
+    # index input paths
+    for path in roots:
+        if not os.path.exists(path):
+            continue
+        elif os.path.isdir(path) and recursive:
+            for dirpath, _, filenames in os.walk(path, topdown=True, followlinks=follow_symlinks):
+                for filename in filenames:
+                    yield os.path.join(dirpath, filename)
+        elif os.path.isfile(path):
+            yield path
+
+## EOF ##