add CURLINFO_SCHEME, CURLINFO_PROTOCOL, and %{scheme}

Adds access to the effectively used protocol/scheme to both libcurl and
curl, both in string and numeric (CURLPROTO_*) form.

Note that the string form will be uppercase, as it is just the internal
string.

As these strings are declared internally as const, and all other strings
returned by curl_easy_getinfo() are de-facto const as well, string
handling in getinfo.c got const-ified.

Closes #1137

5 files changed, 125 insertions, 0 deletions

diff --git a/docs/curl.1 b/docs/curl.1
index d2765ab19..51680315f 100644
--- a/docs/curl.1
+++ b/docs/curl.1
@@ -2068,6 +2068,9 @@ IPv4 or IPv6 (Added in 7.29.0)
 .B remote_port
 The remote port number of the most recently done connection (Added in 7.29.0)
 .TP
+.B scheme
+The URL scheme (sometimes called protocol) that was effectively used (Added in 7.52.0)
+.TP
 .B size_download
 The total amount of bytes that were downloaded.
 .TP
diff --git a/docs/libcurl/curl_easy_getinfo.3 b/docs/libcurl/curl_easy_getinfo.3
index 4f36561ac..fabc7e92f 100644
--- a/docs/libcurl/curl_easy_getinfo.3
+++ b/docs/libcurl/curl_easy_getinfo.3
@@ -183,6 +183,12 @@ See \fICURLINFO_RTSP_SERVER_CSEQ(3)\fP
 .IP CURLINFO_RTSP_CSEQ_RECV
 RTSP CSeq last received.
 See \fICURLINFO_RTSP_CSEQ_RECV(3)\fP
+.IP CURLINFO_PROTOCOL
+The protocol used for the connection. (Added in 7.52.0)
+See \fICURLINFO_PROTOCOL(3)\fP
+.IP CURLINFO_SCHEME
+The scheme used for the connection. (Added in 7.52.0)
+See \fICURLINFO_SCHEME(3)\fP
 .SH TIMES
 .nf
 An overview of the six time values available from curl_easy_getinfo()
diff --git a/docs/libcurl/opts/CURLINFO_PROTOCOL.3 b/docs/libcurl/opts/CURLINFO_PROTOCOL.3
new file mode 100644
index 000000000..b82111876
--- /dev/null
+++ b/docs/libcurl/opts/CURLINFO_PROTOCOL.3
@@ -0,0 +1,55 @@
+.\" **************************************************************************
+.\" *                                  _   _ ____  _
+.\" *  Project                     ___| | | |  _ \| |
+.\" *                             / __| | | | |_) | |
+.\" *                            | (__| |_| |  _ <| |___
+.\" *                             \___|\___/|_| \_\_____|
+.\" *
+.\" * Copyright (C) 1998 - 2016, Daniel Stenberg, <daniel@haxx.se>, et al.
+.\" *
+.\" * This software is licensed as described in the file COPYING, which
+.\" * you should have received as part of this distribution. The terms
+.\" * are also available at https://curl.haxx.se/docs/copyright.html.
+.\" *
+.\" * You may opt to use, copy, modify, merge, publish, distribute and/or sell
+.\" * copies of the Software, and permit persons to whom the Software is
+.\" * furnished to do so, under the terms of the COPYING file.
+.\" *
+.\" * This software is distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY
+.\" * KIND, either express or implied.
+.\" *
+.\" **************************************************************************
+.\"
+.TH CURLINFO_PROTOCOL 3 "23 November 2016" "libcurl 7.52.0" "curl_easy_getinfo options"
+.SH NAME
+CURLINFO_PROTOCOL \- get the protocol used in the connection
+.SH SYNOPSIS
+#include <curl/curl.h>
+
+CURLcode curl_easy_getinfo(CURL *handle, CURLINFO_PROTOCOL, long *p);
+.SH DESCRIPTION
+Pass a pointer to a long to receive the version used in the last http connection.
+The returned value will be one of the CURLPROTO_* values.
+.SH PROTOCOLS
+All
+.SH EXAMPLE
+.nf
+CURL *curl = curl_easy_init();
+if(curl) {
+  CURLcode res;
+  curl_easy_setopt(curl, CURLOPT_URL, "http://example.com");
+  res = curl_easy_perform(curl);
+  if(res == CURLE_OK) {
+    long protocol;
+    curl_easy_getinfo(curl, CURLINFO_PROTOCOL, &protocol);
+  }
+  curl_easy_cleanup(curl);
+}
+.fi
+.SH AVAILABILITY
+Added in 7.52.0
+.SH RETURN VALUE
+Returns CURLE_OK if the option is supported, and CURLE_UNKNOWN_OPTION if not.
+.SH "SEE ALSO"
+.BR CURLINFO_RESPONSE_CODE "(3), "
+.BR curl_easy_getinfo "(3), " curl_easy_setopt "(3), "
diff --git a/docs/libcurl/opts/CURLINFO_SCHEME.3 b/docs/libcurl/opts/CURLINFO_SCHEME.3
new file mode 100644
index 000000000..78c3d6886
--- /dev/null
+++ b/docs/libcurl/opts/CURLINFO_SCHEME.3
@@ -0,0 +1,59 @@
+.\" **************************************************************************
+.\" *                                  _   _ ____  _
+.\" *  Project                     ___| | | |  _ \| |
+.\" *                             / __| | | | |_) | |
+.\" *                            | (__| |_| |  _ <| |___
+.\" *                             \___|\___/|_| \_\_____|
+.\" *
+.\" * Copyright (C) 1998 - 2016, Daniel Stenberg, <daniel@haxx.se>, et al.
+.\" *
+.\" * This software is licensed as described in the file COPYING, which
+.\" * you should have received as part of this distribution. The terms
+.\" * are also available at https://curl.haxx.se/docs/copyright.html.
+.\" *
+.\" * You may opt to use, copy, modify, merge, publish, distribute and/or sell
+.\" * copies of the Software, and permit persons to whom the Software is
+.\" * furnished to do so, under the terms of the COPYING file.
+.\" *
+.\" * This software is distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY
+.\" * KIND, either express or implied.
+.\" *
+.\" **************************************************************************
+.\"
+.TH CURLINFO_SCHEME 3 "23 November 2016" "libcurl 7.52.0" "curl_easy_getinfo options"
+.SH NAME
+CURLINFO_SCHEME \- get the URL scheme (sometimes called protocol) used in the connection
+.SH SYNOPSIS
+#include <curl/curl.h>
+
+CURLcode curl_easy_getinfo(CURL *handle, CURLINFO_SCHEME, long *p);
+.SH DESCRIPTION
+Pass a pointer to a char pointer to receive the pointer to a zero-terminated
+string holding the URL scheme used for the most recent connection done with this
+\fBcurl\fP handle.
+
+The \fBid\fP pointer will be NULL or pointing to private read-only memory you
+MUST NOT free or modify.
+.SH PROTOCOLS
+All
+.SH EXAMPLE
+.nf
+CURL *curl = curl_easy_init();
+if(curl) {
+  CURLcode res;
+  curl_easy_setopt(curl, CURLOPT_URL, "http://example.com");
+  res = curl_easy_perform(curl);
+  if(res == CURLE_OK) {
+    char * scheme;
+    curl_easy_getinfo(curl, CURLINFO_SCHEME, &scheme);
+  }
+  curl_easy_cleanup(curl);
+}
+.fi
+.SH AVAILABILITY
+Added in 7.52.0
+.SH RETURN VALUE
+Returns CURLE_OK if the option is supported, and CURLE_UNKNOWN_OPTION if not.
+.SH "SEE ALSO"
+.BR CURLINFO_RESPONSE_CODE "(3), "
+.BR curl_easy_getinfo "(3), " curl_easy_setopt "(3), "
diff --git a/docs/libcurl/symbols-in-versions b/docs/libcurl/symbols-in-versions
index 1d58d51c1..0831775be 100644
--- a/docs/libcurl/symbols-in-versions
+++ b/docs/libcurl/symbols-in-versions
@@ -239,6 +239,7 @@ CURLINFO_PRETRANSFER_TIME       7.4.1
 CURLINFO_PRIMARY_IP             7.19.0
 CURLINFO_PRIMARY_PORT           7.21.0
 CURLINFO_PRIVATE                7.10.3
+CURLINFO_PROTOCOL               7.52.0
 CURLINFO_PROXYAUTH_AVAIL        7.10.8
 CURLINFO_PROXY_SSL_VERIFYRESULT 7.52.0
 CURLINFO_REDIRECT_COUNT         7.9.7
@@ -250,6 +251,7 @@ CURLINFO_RTSP_CLIENT_CSEQ       7.20.0
 CURLINFO_RTSP_CSEQ_RECV         7.20.0
 CURLINFO_RTSP_SERVER_CSEQ       7.20.0
 CURLINFO_RTSP_SESSION_ID        7.20.0
+CURLINFO_SCHEME                 7.52.0
 CURLINFO_SIZE_DOWNLOAD          7.4.1
 CURLINFO_SIZE_UPLOAD            7.4.1
 CURLINFO_SLIST                  7.12.3