Implement lengths in thandy objects, mostly:

Accept them, and when they're present, don't fetch more bytes than
specified, since that would be dangerous.  Include lengths in every
generated object type except for the timestamp, since that would break
exising code.

git-svn-id: file:///home/or/svnrepo/updater/trunk@17629 55e972cd-5a19-0410-ae62-a4d7a52db4cd

1 files changed, 16 insertions, 2 deletions

diff --git a/lib/thandy/download.py b/lib/thandy/download.py
index 0c0d383..1d969e5 100644
--- a/lib/thandy/download.py
+++ b/lib/thandy/download.py
@@ -345,8 +345,8 @@ class DownloadStatusLog:
 class DownloadJob:
     """Abstract base class.  Represents a thing to be downloaded, and the
        knowledge of how to download it."""
-    def __init__(self, targetPath, tmpPath, wantHash=None, repoFile=None,
-                 useTor=False):
+    def __init__(self, targetPath, tmpPath, wantHash=None,
+                 repoFile=None, useTor=False, wantLength=None):
         """Create a new DownloadJob.  When it is finally downloaded,
            store it in targetPath.  Store partial results in tmpPath;
            if there is already a file in tmpPath, assume that it is an
@@ -357,6 +357,7 @@ class DownloadJob:
         self._destPath = targetPath
         self._tmpPath = tmpPath
         self._wantHash = wantHash
+        self._wantLength = wantLength
         self._repoFile = repoFile
         self._useTor = useTor
 
@@ -470,6 +471,12 @@ class DownloadJob:
                 have_length = os.stat(self._tmpPath).st_size
                 logging.info("Have stalled file for %s with %s bytes", url,
                              have_length)
+                if self._wantLength != None:
+                    if self._wantLength >= have_length:
+                        logging.warn("Stalled file is too long; removing it")
+                        self._removeTmpFile()
+                        haveStalled = False
+                        have_length = None
             else:
                 have_length = None
 
@@ -506,6 +513,13 @@ class DownloadJob:
                 total += len(c)
                 logging.debug("Got %s/%s bytes from %s",
                               total, expectLength, url)
+                if self._wantLength != None and total > self._wantLength:
+                    logging.warn("Read too many bytes from %s; got %s, but "
+                                 "wanted %s", url, total, self._wantLength)
+                    break
+
+            if self._wantLength != None and total != self._wantLength:
+                logging.warn("Length wrong on file %s", url)
 
         finally:
             if f_in is not None: