1 files changed, 94 insertions, 0 deletions
diff --git a/startop/scripts/iorap/lib/inode2filename.py b/startop/scripts/iorap/lib/inode2filename.py
new file mode 100644
index 000000000000..2e713936319a
--- /dev/null
+++ b/startop/scripts/iorap/lib/inode2filename.py
@@ -0,0 +1,94 @@
+#!/usr/bin/env python3
+
+#
+# Copyright (C) 2019 The Android Open Source Project
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#      http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+#
+
+from typing import Any, Callable, Dict, Generic, Iterable, List, NamedTuple, TextIO, Tuple, TypeVar, Optional, Union, TextIO
+
+import re
+
+class Inode2Filename:
+  """
+  Parses a text file of the format
+     "uint(dev_t) uint(ino_t) int(file_size) string(filepath)\\n"*
+
+  Lines not matching this format are ignored.
+  """
+
+  def __init__(self, inode_data_file: TextIO):
+    """
+    Create an Inode2Filename that reads cached inode from a file saved earlier
+    (e.g. with pagecache.py -d or with inode2filename --format=textcache)
+
+    :param inode_data_file: a file object (e.g. created with open or StringIO).
+
+    Lifetime: inode_data_file is only used during the construction of the object.
+    """
+    self._inode_table = Inode2Filename.build_inode_lookup_table(inode_data_file)
+
+  @classmethod
+  def new_from_filename(cls, textcache_filename: str) -> 'Inode2Filename':
+    """
+    Create an Inode2Filename that reads cached inode from a file saved earlier
+    (e.g. with pagecache.py -d or with inode2filename --format=textcache)
+
+    :param textcache_filename: path to textcache
+    """
+    with open(textcache_filename) as inode_data_file:
+      return cls(inode_data_file)
+
+  @staticmethod
+  def build_inode_lookup_table(inode_data_file: TextIO) -> Dict[Tuple[int, int], Tuple[str, str]]:
+    """
+    :return: map { (device_int, inode_int) -> (filename_str, size_str) }
+    """
+    inode2filename = {}
+    for line in inode_data_file:
+      # stat -c "%d %i %s %n
+      # device number, inode number, total size in bytes, file name
+      result = re.match('([0-9]+)d? ([0-9]+) -?([0-9]+) (.*)', line)
+      if result:
+        inode2filename[(int(result.group(1)), int(result.group(2)))] = \
+            (result.group(4), result.group(3))
+
+    return inode2filename
+
+  def resolve(self, dev_t: int, ino_t: int) -> Optional[str]:
+    """
+    Return a filename (str) from a (dev_t, ino_t) inode pair.
+
+    Returns None if the lookup fails.
+    """
+    maybe_result = self._inode_table.get((dev_t, ino_t))
+
+    if not maybe_result:
+      return None
+
+    return maybe_result[0] # filename str
+
+  def __len__(self) -> int:
+    """
+    :return: the number of inode entries parsed from the file.
+    """
+    return len(self._inode_table)
+
+  def __repr__(self) -> str:
+    """
+    :return: string representation for debugging/test failures.
+    """
+    return "Inode2Filename%s" %(repr(self._inode_table))
+
+  # end of class.