When we introduced curl_easy_perform_ev, this got a slightly modified
call trace. Without this, test 165 causes a false positive valgrind
error.

Without this, test 165 triggers a valgrind error when ran with
curl_easy_perform_ev

When waiting for a 100-continue response from the server, the
Curl_readwrite() will refuse to run if called until the timeout has been
reached.

We timeout code in multi_socket() allows code to run slightly before the
actual timeout time, so for test 154 it could lead to the function being
executed but refused in Curl_readwrite() and then the application would
just sit idling forever.

This was detected with runtests.pl -e on test 154.

warning: implicit declaration of function 'checkpasswd'

Moved the calls to checkpasswd() out of the getparameter() function
which allows for any related arguments to be specified on the command
line before or after --user (and --proxy-user).

For example: --bearer doesn't need to be specified before --user to
prevent curl from asking for an unnecessary password as is the case
with commit e7dcc454.

Added the --bearer option to the help output

Added the ability to specify an XOAUTH2 bearer token [RFC6750] via the
--bearer option.

Example usage:
  curl --url "imaps://imap.gmail.com:993/INBOX/;UID=1" --ssl-reqd
  --bearer ya29.AHES6Z...OMfsHYI --user username@example.com

warning: 'variable' may be used uninitialized in this function

I brought back security.h in commit bb552933. As we actually
already found out back in 2005 in commit 62970da6, the file name
security.h causes problems so I renamed it curl_sec.h instead.

The specified curl binary will then be used to verify the running
server(s) instead of the development version. This is very useful in
some cases when the development version fails to verify correctly as
then the test case may not run at all.

The actual test will still be run with the "normal" curl executable
(unless the test case specifies something differently).

Added the ability to use an XOAUTH2 bearer token [RFC6750] with SMTP for
authentication using RFC6749 "OAuth 2.0 Authorization Framework".

The bearer token is expected to be valid for the user specified in
conn->user. If CURLOPT_XOAUTH2_BEARER is defined and the connection has
an advertised auth mechanism of "XOAUTH2", the user and access token are
formatted as a base64 encoded string and sent to the server as
"AUTH XOAUTH2 <bearer token>".

Added the ability to use an XOAUTH2 bearer token [RFC6750] with IMAP for
authentication using RFC6749 "OAuth 2.0 Authorization Framework".

The bearer token is expected to be valid for the user specified in
conn->user. If CURLOPT_XOAUTH2_BEARER is defined and the connection has
an advertised auth mechanism of "XOAUTH2", the user and access token are
formatted as a base64 encoded string and sent to the server as
"A001 AUTHENTICATE XOAUTH2 <bearer token>".

ISO C forbids forward references to 'enum' types

The old numbers would still redirect but who knows for how long...

Added the ability to specify an XOAUTH2 bearer token [RFC6750] via the
option CURLOPT_XOAUTH2_BEARER for authentication using RFC6749 "OAuth
2.0 Authorization Framework".

Added the ability to generated a base64 encoded XOAUTH2 token
containing: "user=<username>^Aauth=Bearer <bearer token>^A^A"
as per RFC6749 "OAuth 2.0 Authorization Framework".

We've announced this pending removal for a long time and we've
repeatedly asked if anyone would care or if anyone objects. Nobody has
objected. It has probably not even been working for a good while since
nobody has tested/used this code recently.

The stuff in krb4.h that was generic enough to be used by other sources
is now present in security.h

Several language fixes. Several reformats that should make the HTML
generation of this document look better.

Reported-by: Dave Thompson

Make sure we always return CURLM_CALL_MULTI_PERFORM when we reach
CURLM_STATE_DONE since the state is transient and it can very well
continue executing as there is nothing to wait for.

Bug: http://curl.haxx.se/mail/lib-2013-08/0211.html
Reported-by: Yi Huang

Renamed to "enum curl_khtype" now. Will break compilation for programs
that rely on the enum name.

Bug: https://github.com/bagder/curl/pull/76
Reported-by: Shawn Landden

... this also makes sure that the progess callback gets called more
often during TFTP transfers.

Added test 1238 to verify.

Bug: http://curl.haxx.se/bug/view.cgi?id=1269
Reported-by: Jo3

I build curl.exe (using MingW) with '-DCURLDEBUG' and by importing from
libcurl.dll.  Which means the new curl_easy_perform_ev() must be
exported from libcurl.dll.

Doing curl_multi_add_handle() on an easy handle that is already added to
a multi handle now returns this error code. It previously returned
CURLM_BAD_EASY_HANDLE for this condition.

The closure_handle is "owned" by the multi handle and it is
unconditional so the setting up of it should be in the Curl_multi_handle
function rather than curl_multi_add_handle.

As it is done unconditionally in multi_init() this code will never run!

This function is meant to work *exactly* as curl_easy_perform() but will
use the event-based libcurl API internally instead of
curl_multi_perform(). To avoid relying on an actual event-based library
and to not use non-portable functions (like epoll or similar), there's a
rather inefficient emulation layer implemented on top of Curl_poll()
instead.

There's currently some convenience logging done in curl_easy_perform_ev
which helps when tracking down problems. They may be suitable to remove
or change once things seem to be fine enough.

curl has a new --test-event option when built with debug enabled that
then uses curl_easy_perform_ev() instead of curl_easy_perform(). If
built without debug, using --test-event will only output a warning
message.

NOTE: curl_easy_perform_ev() is not part if the public API on purpose.
It is only present in debug builds of libcurl and MUST NOT be considered
stable even then. Use it for libcurl-testing purposes only.

runtests.pl now features an -e command line option that makes it use
--test-event for all curl command line tests. The man page is updated.

libcurl quietly truncates usernames, passwords, and options from
before an '@' sign in a URL to 255 (= MAX_CURL_PASSWORD_LENGTH - 1)
characters to fit in fixed-size buffers on the stack.  Allocate a
buffer large enough to fit the parsed fields on the fly instead to
support longer passwords.

After this change, there are no more uses of MAX_CURL_OPTIONS_LENGTH
left, so stop defining that constant while at it.  The hardcoded max
username and password length constants, on the other hand, are still
used in HTTP proxy credential handling (which this patch doesn't
touch).

Reported-by: Colby Ranger

Instead of nesting "if(success)" blocks and leaving the reader in
suspense about what happens in the !success case, deal with failure
cases early, usually with a simple goto to clean up and return from
the function.

No functional change intended.  The main effect is to decrease the
indentation of this function slightly.