Support cancellation in push operation

This commit adds cancellation for the push operation. This work consists of:

1) Support cancellation during push operation
    - During object counting phase
    - During network transfer phase
        - Propagate GIT_EUSER error code out to caller
2) Improve cancellation support during fetch
    - Handle cancellation request during network transfer phase
    - Clear error string when cancelled during indexing
3) Fix error handling in git_smart__download_pack

Cancellation during push is still only handled in the pack building and
network transfer stages of push (and not during packbuilding).

1 files changed, 1 insertions, 1 deletions

diff --git a/src/transports/smart.h b/src/transports/smart.h
index c52401a3c..3519477da 100644
--- a/src/transports/smart.h
+++ b/src/transports/smart.h
@@ -119,7 +119,7 @@ typedef struct transport_smart_caps {
 		report_status:1;
 } transport_smart_caps;
 
-typedef void (*packetsize_cb)(size_t received, void *payload);
+typedef int (*packetsize_cb)(size_t received, void *payload);
 
 typedef struct {
 	git_transport parent;