AU: Fix potential issues with premature destruction of HTTP fetchers.
This patch adds a new TransferTerminated callback to the
HttpFetcher class. It fixes two potential memory corruption
issues with premature destruction of HttpFetcher instances:
1. When MultiHttpFetcher completes a range, it terminates
the current fetcher and starts the next one, if any. Change
so that the next fetcher is started when the
TransferTerminated callback is received from the current
fetcher. This prevents the multi fetcher from sending a
TransferComplete/TransferTerminated callbacks before the
underlying fetcher is cleaned up, which may lead to the
fetchers being destroyed prematurely.
2. If the download action fails due to a failed write,
terminate the transfer and then wait for the transfer
terminated callback before notifying the action processor
that the action is complete. Otherwise, the action may get
destroyed before the transfer is actually terminated
possibly leading to memory corruption, etc.
Hopefully these changes fix crosbug.com/8798.
BUG=8798
TEST=unit tests, tested on device with write errors
Change-Id: If416b95625ab31662f2e1308df6bdd1757a2ad78
Review URL: http://codereview.chromium.org/5009009
diff --git a/libcurl_http_fetcher.h b/libcurl_http_fetcher.h
index 3a50bda..b3ba518 100644
--- a/libcurl_http_fetcher.h
+++ b/libcurl_http_fetcher.h
@@ -48,8 +48,8 @@
// Begins the transfer if it hasn't already begun.
virtual void BeginTransfer(const std::string& url);
- // If the transfer is in progress, aborts the transfer early.
- // The transfer cannot be resumed.
+ // If the transfer is in progress, aborts the transfer early. The transfer
+ // cannot be resumed.
virtual void TerminateTransfer();
// Suspend the transfer by calling curl_easy_pause(CURLPAUSE_ALL).
@@ -136,6 +136,11 @@
// curl(m) handles, io_channels_, timeout_source_.
void CleanUp();
+ // Force terminate the transfer. This will invoke the delegate's (if any)
+ // TransferTerminated callback so, after returning, this fetcher instance may
+ // be destroyed.
+ void ForceTransferTermination();
+
// Returns whether or not the current network connection is considered
// expensive.
bool ConnectionIsExpensive() const;