On Sun, 28 Apr 2024, Matheus Afonso Martins Moreira via GitGitGadget <gitgitgadget@gmail.com> wrote:
> From: Matheus Afonso Martins Moreira <matheus@matheusmoreira.com>
> 
> Define general parsing function that supports all Git URLs
> including scp style URLs such as hostname:~user/repo.
> Has the same interface as the URL normalization function
> and uses the same data structures, facilitating its use.
> It's adapted from the algorithm used to process URLs in connect.c,
> so it should support the same inputs.
> 
> Signed-off-by: Matheus Afonso Martins Moreira <matheus@matheusmoreira.com>
> ---
>  urlmatch.c | 90 ++++++++++++++++++++++++++++++++++++++++++++++++++++++
>  urlmatch.h |  1 +
>  2 files changed, 91 insertions(+)
> 
> diff --git a/urlmatch.c b/urlmatch.c
> index 1d0254abacb..5a442e31fa2 100644
> --- a/urlmatch.c
> +++ b/urlmatch.c
> @@ -3,6 +3,7 @@
>  #include "hex-ll.h"
>  #include "strbuf.h"
>  #include "urlmatch.h"
> +#include "url.h"
>  
>  #define URL_ALPHA "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz"
>  #define URL_DIGIT "0123456789"
> @@ -438,6 +439,95 @@ char *url_normalize(const char *url, struct url_info *out_info)
>  	return url_normalize_1(url, out_info, 0);
>  }
>  
> +enum protocol {
> +	PROTO_UNKNOWN = 0,
> +	PROTO_LOCAL,
> +	PROTO_FILE,
> +	PROTO_SSH,
> +	PROTO_GIT,
> +};
> +
> +static enum protocol url_get_protocol(const char *name, size_t n)
> +{
> +	if (!strncmp(name, "ssh", n))
> +		return PROTO_SSH;
> +	if (!strncmp(name, "git", n))
> +		return PROTO_GIT;
> +	if (!strncmp(name, "git+ssh", n)) /* deprecated - do not use */
> +		return PROTO_SSH;
> +	if (!strncmp(name, "ssh+git", n)) /* deprecated - do not use */
> +		return PROTO_SSH;
> +	if (!strncmp(name, "file", n))
> +		return PROTO_FILE;
> +	return PROTO_UNKNOWN;
> +}
> +
> +char *url_parse(const char *url_orig, struct url_info *out_info)
> +{
> +	struct strbuf url;
> +	char *host, *separator;
> +	char *detached, *normalized;
> +	enum protocol protocol = PROTO_LOCAL;
> +	struct url_info local_info;
> +	struct url_info *info = out_info? out_info : &local_info;
> +	bool scp_syntax = false;
> +
> +	if (is_url(url_orig)) {
> +		url_orig = url_decode(url_orig);
> +	} else {
> +		url_orig = xstrdup(url_orig);
> +	}
> +
> +	strbuf_init(&url, strlen(url_orig) + sizeof("ssh://"));
> +	strbuf_addstr(&url, url_orig);
> +
> +	host = strstr(url.buf, "://");
> +	if (host) {
> +		protocol = url_get_protocol(url.buf, host - url.buf);
> +		host += 3;
> +	} else {
> +		if (!url_is_local_not_ssh(url.buf)) {
> +			scp_syntax = true;
> +			protocol = PROTO_SSH;
> +			strbuf_insertstr(&url, 0, "ssh://");
> +			host = url.buf + 6;
> +		}
> +	}
Interesting. 

    `
    $ ./git url-parse -c protocol file:/test/test
    ssh
    `

seems like only having a single slash after the 'protocol:' prints
'ssh' always (I think this may not even be a valid url). After this 'else'
block, the url turns into 'ssh://file/test/test'. Will examine the details
later. Not that it's your code's doing, and rather the result of
url_is_local_not_ssh(). But just wanted to point this out and ask if this
should error out or is this an intended behavior that I can't figure out. 

Thanks.

[]
> Interesting.
>
>     `
>     $ ./git url-parse -c protocol file:/test/test
>     ssh
>     `
>
> seems like only having a single slash after the 'protocol:' prints
> 'ssh' always (I think this may not even be a valid url). After this 'else'
> block, the url turns into 'ssh://file/test/test'. Will examine the details
> later. Not that it's your code's doing, and rather the result of
> url_is_local_not_ssh(). But just wanted to point this out and ask if this
> should error out or is this an intended behavior that I can't figure out.

ssh is the correct answer, try something like

`git clone localhost:/home/myself/project/git.git`

It is the scp syntax, supported by Git as well.
From `man scp`

    scp copies files between hosts on a network.
    []
    The source and target may be specified as a local pathname,
    a remote host with optional path in the form
    [user@]host:[path],
    or a URI in the form scp://[user@]host[:port][/path].
    Local file names can be made explicit using absolute or relative pathnames
    to avoid scp treating file names containing ‘:’ as host specifiers.

So yes, they share similar problems
with the ':' that could mean different things when using the short form.