[PATCH] add http.maxReceiveSpeed to limit git-receive-pack receiving speed

[Xia XiaoWen <haoyurenzhuxia@gmail.com>]

Sometimes need to limit the receive speed of git `clone/fetch`
because of the limited network bandwidth, otherwise will prevent
other applications from using the network normally.

Add `http.maxReceiveSpeed` to limit `git-receive-pack` receiving
speed, Can be overridden by `GIT_HTTP_MAX_RECEIVE_SPEED` eivironment
variable.

The default is unlimited, same if the value is 0 or negative. The
default unit is Bytes/s, common unit suffixes of k, m, or g are supported.

this configuration is valid for `clone`, `fetch`, `pull` commands of the
https protocol, and only supports libcurl 7.15.5 and above.
---
 http.c | 24 +++++++++++++++++++++++-
 1 file changed, 23 insertions(+), 1 deletion(-)

diff --git a/http.c b/http.c
index 8119247149..12030cf3bc 100644
--- a/http.c
+++ b/http.c
@@ -83,6 +83,9 @@ static const char *ssl_pinnedkey;
 static const char *ssl_cainfo;
 static long curl_low_speed_limit = -1;
 static long curl_low_speed_time = -1;
+#if LIBCURL_VERSION_NUM >= 0x070f05
+static ssize_t curl_max_receive_speed = -1;
+#endif
 static int curl_ftp_no_epsv;
 static const char *curl_http_proxy;
 static const char *http_proxy_authmethod;
@@ -361,7 +364,12 @@ static int http_options(const char *var, const char *value, void *cb)
 		curl_low_speed_time = (long)git_config_int(var, value);
 		return 0;
 	}
-
+#if LIBCURL_VERSION_NUM >= 0x070f05
+	if (!strcmp("http.maxreceivespeed", var)) {
+		curl_max_receive_speed = git_config_ssize_t(var, value);
+		return 0;
+	}
+#endif
 	if (!strcmp("http.noepsv", var)) {
 		curl_ftp_no_epsv = git_config_bool(var, value);
 		return 0;
@@ -974,6 +982,12 @@ static CURL *get_curl_handle(void)
 				 curl_low_speed_time);
 	}
 
+#if LIBCURL_VERSION_NUM >= 0x070f05
+	if (curl_max_receive_speed > 0)
+		curl_easy_setopt(result, CURLOPT_MAX_RECV_SPEED_LARGE,
+				 curl_max_receive_speed);
+#endif
+
 	curl_easy_setopt(result, CURLOPT_MAXREDIRS, 20);
 #if LIBCURL_VERSION_NUM >= 0x071301
 	curl_easy_setopt(result, CURLOPT_POSTREDIR, CURL_REDIR_POST_ALL);
@@ -1105,6 +1119,9 @@ void http_init(struct remote *remote, const char *url, int proactive_auth)
 {
 	char *low_speed_limit;
 	char *low_speed_time;
+#if LIBCURL_VERSION_NUM >= 0x070f05
+	char *max_receive_speed;
+#endif
 	char *normalized_url;
 	struct urlmatch_config config = { STRING_LIST_INIT_DUP };
 
@@ -1196,6 +1213,11 @@ void http_init(struct remote *remote, const char *url, int proactive_auth)
 	low_speed_time = getenv("GIT_HTTP_LOW_SPEED_TIME");
 	if (low_speed_time != NULL)
 		curl_low_speed_time = strtol(low_speed_time, NULL, 10);
+#if LIBCURL_VERSION_NUM >= 0x070f05
+	max_receive_speed = getenv("GIT_HTTP_MAX_RECEIVE_SPEED");
+	if (max_receive_speed && !git_parse_ssize_t(max_receive_speed, &curl_max_receive_speed))
+		warning("failed to parse GIT_HTTP_MAX_RECEIVE_SPEED: %s", max_receive_speed);
+#endif
 
 	if (curl_ssl_verify == -1)
 		curl_ssl_verify = 1;
-- 
2.28.1.49.gafcb914ae4.dirty.agit.6.3.1