Re: [PATCH 1/5] connect: split git:// setup into a separate function

[Jonathan Nieder <jrnieder@gmail.com>]

Hi,

On Oct 24, 2017, Junio C Hamano wrote:
> Jonathan Nieder <jrnieder@gmail.com> writes:

>> +static struct child_process *git_connect_git(int fd[2], char *hostandport,
>> +					     const char *path, const char *prog,
>> +					     int flags)
>> +{
>> +	struct child_process *conn = &no_fork;
>> +	struct strbuf request = STRBUF_INIT;
>
> As this one decides what "conn" to return, including the fallback
> &no_fork instance,...
>
>> +	...
>> +	return conn;
>> +}
>> +
>>  /*
>>   * This returns a dummy child_process if the transport protocol does not
>>   * need fork(2), or a struct child_process object if it does.  Once done,
>> @@ -881,50 +939,7 @@ struct child_process *git_connect(int fd[2], const char *url,
>
> Each of the if/elseif/ cascade, one of which calls the new helper,
> now makes an explicit assignment to "conn" declared in
> git_connect().
>
> Which means the defaulting of git_connect::conn to &no_fork is now
> unneeded.  One of the things that made the original cascade a bit
> harder to follow than necessary, aside from the physical length of
> the PROTO_GIT part, was that the case where conn remains to point at
> no_fork looked very special and it was buried in that long PROTO_GIT
> part.

Good idea.  Here's what I'll include in the reroll.

-- >8 --
Subject: connect: move no_fork fallback to git_tcp_connect

git_connect has the structure

	struct child_process *conn = &no_fork;

	...
	switch (protocol) {
	case PROTO_GIT:
		if (git_use_proxy(hostandport))
			conn = git_proxy_connect(fd, hostandport);
		else
			git_tcp_connect(fd, hostandport, flags);
		...
		break;
	case PROTO_SSH:
		conn = xmalloc(sizeof(*conn));
		child_process_init(conn);
		argv_array_push(&conn->args, ssh);
		...
		break;
	...
	return conn;

In all cases except the git_tcp_connect case, conn is explicitly
assigned a value. Make the code clearer by explicitly assigning
'conn = &no_fork' in the tcp case and eliminating the default so the
compiler can ensure conn is always correctly assigned.

Noticed-by: Junio C Hamano <gitster@pobox.com>
Signed-off-by: Jonathan Nieder <jrnieder@gmail.com>
---
 connect.c | 22 ++++++++++++----------
 1 file changed, 12 insertions(+), 10 deletions(-)

diff --git a/connect.c b/connect.c
index 7fbd396b35..b6accf71cb 100644
--- a/connect.c
+++ b/connect.c
@@ -582,12 +582,21 @@ static int git_tcp_connect_sock(char *host, int flags)
 #endif /* NO_IPV6 */
 
 
-static void git_tcp_connect(int fd[2], char *host, int flags)
+static struct child_process no_fork = CHILD_PROCESS_INIT;
+
+int git_connection_is_socket(struct child_process *conn)
+{
+	return conn == &no_fork;
+}
+
+static struct child_process *git_tcp_connect(int fd[2], char *host, int flags)
 {
 	int sockfd = git_tcp_connect_sock(host, flags);
 
 	fd[0] = sockfd;
 	fd[1] = dup(sockfd);
+
+	return &no_fork;
 }
 
 
@@ -761,8 +770,6 @@ static enum protocol parse_connect_url(const char *url_orig, char **ret_host,
 	return protocol;
 }
 
-static struct child_process no_fork = CHILD_PROCESS_INIT;
-
 static const char *get_ssh_command(void)
 {
 	const char *ssh;
@@ -865,7 +872,7 @@ struct child_process *git_connect(int fd[2], const char *url,
 				  const char *prog, int flags)
 {
 	char *hostandport, *path;
-	struct child_process *conn = &no_fork;
+	struct child_process *conn;
 	enum protocol protocol;
 
 	/* Without this we cannot rely on waitpid() to tell
@@ -901,7 +908,7 @@ struct child_process *git_connect(int fd[2], const char *url,
 		if (git_use_proxy(hostandport))
 			conn = git_proxy_connect(fd, hostandport);
 		else
-			git_tcp_connect(fd, hostandport, flags);
+			conn = git_tcp_connect(fd, hostandport, flags);
 		/*
 		 * Separate original protocol components prog and path
 		 * from extended host header with a NUL byte.
@@ -1041,11 +1048,6 @@ struct child_process *git_connect(int fd[2], const char *url,
 	return conn;
 }
 
-int git_connection_is_socket(struct child_process *conn)
-{
-	return conn == &no_fork;
-}
-
 int finish_connect(struct child_process *conn)
 {
 	int code;
-- 
2.15.0.448.gf294e3d99a