index.Reader.filter: throw when parent's missing (don't assert)

[bup.git] / lib / bup / index.py

diff --git a/lib/bup/index.py b/lib/bup/index.py
index d0df52a4bbe158b661e5df44bda8b1b22b1c6d1f..3b98892b41b6b223bf74c9d4c5779439b718376f 100644 (file)
--- a/lib/bup/index.py
+++ b/lib/bup/index.py
@@ -50,14 +50,19 @@ class Error(Exception):
 
 class MetaStoreReader:
     def __init__(self, filename):
+        self._closed = False
         self._file = None
         self._file = open(filename, 'rb')
 
     def close(self):
+        self._closed = True
         if self._file:
             self._file.close()
             self._file = None
 
+    def __del__(self):
+        assert self._closed
+
     def __enter__(self):
         return self
 
@@ -75,6 +80,7 @@ class MetaStoreWriter:
     # truncation or corruption somewhat sensibly.
 
     def __init__(self, filename):
+        self._closed = False
         # Map metadata hashes to bupindex.meta offsets.
         self._offsets = {}
         self._filename = filename
@@ -101,10 +107,14 @@ class MetaStoreWriter:
         self._file = open(filename, 'ab')
 
     def close(self):
+        self._closed = True
         if self._file:
             self._file.close()
             self._file = None
 
+    def __del__(self):
+        assert self._closed
+
     def __enter__(self):
         return self
 
@@ -413,6 +423,7 @@ class ExistingEntry(Entry):
 
 class Reader:
     def __init__(self, filename):
+        self.closed = False
         self.filename = filename
         self.m = b''
         self.writable = False
@@ -439,8 +450,12 @@ class Reader:
                                                self.m[st.st_size - FOOTLEN
                                                       : st.st_size])[0]
 
-    def __del__(self):
-        self.close()
+    def __enter__(self):
+        return self
+
+    def __exit__(self, type, value, traceback):
+        with pending_raise(value, rethrow=False):
+            self.close()
 
     def __len__(self):
         return int(self.count)
@@ -484,12 +499,16 @@ class Reader:
             self.m.flush()
 
     def close(self):
+        self.closed = True
         self.save()
         if self.writable and self.m:
             self.m.close()
             self.m = None
             self.writable = False
 
+    def __del__(self):
+        assert self.closed
+
     def filter(self, prefixes, wantrecurse=None):
         for (rp, path) in reduce_paths(prefixes):
             any_entries = False
@@ -503,7 +522,8 @@ class Reader:
                 # Otherwise something like "save x/y" will produce
                 # nothing if x is up to date.
                 pe = self.find(rp)
-                assert(pe)
+                if not pe:
+                    raise Exception("cannot find %r" % rp)
                 name = path + pe.name[len(rp):]
                 yield (name, pe)
 
@@ -520,6 +540,7 @@ def pathsplit(p):
 
 class Writer:
     def __init__(self, filename, metastore, tmax):
+        self.closed = False
         self.rootlevel = self.level = Level([], None)
         self.f = None
         self.count = 0
@@ -533,10 +554,15 @@ class Writer:
         self.f = os.fdopen(ffd, 'wb', 65536)
         self.f.write(INDEX_HDR)
 
-    def __del__(self):
-        self.abort()
+    def __enter__(self):
+        return self
+
+    def __exit__(self, type, value, traceback):
+        with pending_raise(value, rethrow=False):
+            self.abort()
 
     def abort(self):
+        self.closed = True
         f = self.f
         self.f = None
         if f:
@@ -555,6 +581,7 @@ class Writer:
         assert(self.level == None)
 
     def close(self):
+        self.closed = True
         self.flush()
         f = self.f
         self.f = None
@@ -562,6 +589,9 @@ class Writer:
             f.close()
             os.rename(self.tmpname, self.filename)
 
+    def __del__(self):
+        assert self.closed
+
     def _add(self, ename, entry):
         if self.lastfile and self.lastfile <= ename:
             raise Error('%r must come before %r'