_mountinfo: replace list of entries with OrderedDict

Mapping mount id to entries.

1 files changed, 16 insertions, 7 deletions

diff --git a/lbup/_mountinfo.py b/lbup/_mountinfo.py
index 763884b..673378a 100644
--- a/lbup/_mountinfo.py
+++ b/lbup/_mountinfo.py
@@ -1,3 +1,5 @@
+from collections import OrderedDict
+
 import os.path
 
 from ._path import AbsPath
@@ -98,32 +100,39 @@ class MountInfo:
     A wrapper around the contents of the Linux /proc/<pid>/mountinfo file.
     """
 
-    "a list of _MountEntry"
-    entries = None
+    mounts = None
+    "OrderedDict of 'mount ID' -> _MountEntry"
 
     def __init__(self, data):
-        self.entries = []
+        mounts = OrderedDict()
         for line in data.splitlines():
             try:
-                self.entries.append(_MountEntry(line))
+                e = _MountEntry(line)
             except NotAbsRoot:
                 pass
 
+            if e.mount_id in mounts:
+                raise ValueError('Duplicate mount ID: %s' % str(e.mount_id))
+
+            mounts[e.mount_id] = e
+
+        self.mounts = mounts
+
     def __str__(self):
-        return '%s(%d entries)' % (self.__class__.__name__, len(self.entries))
+        return '%s(%d entries)' % (self.__class__.__name__, len(self.mounts))
 
     def entries_for_mountpoint(self, mountpoint):
         """
         Iterate over all mountinfo entries mounted at the given mountpoint.
         """
-        return filter(lambda entry: entry.mount_point == mountpoint, self.entries)
+        return filter(lambda entry: entry.mount_point == mountpoint, self.mounts.values())
 
     def mountpoint_for_path(self, path):
         """
         Find the longest mountpoint that is a parent of path.
         """
         best_match = None
-        for e in self.entries:
+        for e in self.mounts.values():
             if (path in e.mount_point and
                 (best_match is None or len(best_match) < len(e.mount_point))):
                 best_match = e.mount_point