[PATCH] rev-parse --namespace

[PATCH] rev-parse --namespace

[Ilari Liusvaara]

Add --namespace=<namespace> option to rev-parse and everything that
accepts its options. This option matches all refs in some subnamespace
of refs hierarchy, and is useful for selecting everything reachable from
one or few, but not all remotes (--namespace=remotes/foo).

Signed-off-by: Ilari Liusvaara <ilari.liusvaara@elisanet.fi>
---
Another one from my todo list. Based on master branch.

 Documentation/git-rev-list.txt     |    1 +
 Documentation/git-rev-parse.txt    |    4 ++
 Documentation/rev-list-options.txt |    6 ++
 builtin-rev-parse.c                |    6 ++
 refs.c                             |   33 +++++++++++
 refs.h                             |    9 +++
 revision.c                         |    5 ++
 t/t6018-rev-list-namespace.sh      |  103 ++++++++++++++++++++++++++++++++++++
 8 files changed, 167 insertions(+), 0 deletions(-)
 create mode 100755 t/t6018-rev-list-namespace.sh

diff --git a/Documentation/git-rev-list.txt b/Documentation/git-rev-list.txt
index 3341d1b..a8f8f22 100644
--- a/Documentation/git-rev-list.txt
+++ b/Documentation/git-rev-list.txt
@@ -24,6 +24,7 @@ SYNOPSIS
 	     [ \--branches ]
 	     [ \--tags ]
 	     [ \--remotes ]
+	     [ \--namespace=namespace-prefix ]
 	     [ \--stdin ]
 	     [ \--quiet ]
 	     [ \--topo-order ]
diff --git a/Documentation/git-rev-parse.txt b/Documentation/git-rev-parse.txt
index 82045a2..af4605a 100644
--- a/Documentation/git-rev-parse.txt
+++ b/Documentation/git-rev-parse.txt
@@ -112,6 +112,10 @@ OPTIONS
 --remotes::
 	Show tag refs found in `$GIT_DIR/refs/remotes`.
 
+--namespace=namespace-prefix::
+	Show refs found in `$GIT_DIR/namespace-prefix`. If namespace
+	specified lacks leading 'refs/', it is automatically prepended.
+
 --show-prefix::
 	When the command is invoked from a subdirectory, show the
 	path of the current directory relative to the top-level
diff --git a/Documentation/rev-list-options.txt b/Documentation/rev-list-options.txt
index 1f57aed..c824a7b 100644
--- a/Documentation/rev-list-options.txt
+++ b/Documentation/rev-list-options.txt
@@ -243,6 +243,12 @@ endif::git-rev-list[]
 	Pretend as if all the refs in `$GIT_DIR/refs/remotes` are listed
 	on the command line as '<commit>'.
 
+--namespace=namespace-prefix::
+	Pretend as if all the refs in `$GIT_DIR/namespace-prefix` are
+	listed on the command line as '<commit>'. Leading 'refs/', it
+	is automatically prepended if missing.
+
+
 ifndef::git-rev-list[]
 --bisect::
 
diff --git a/builtin-rev-parse.c b/builtin-rev-parse.c
index 37d0233..d7cb3c1 100644
--- a/builtin-rev-parse.c
+++ b/builtin-rev-parse.c
@@ -52,6 +52,7 @@ static int is_rev_argument(const char *arg)
 		"--parents",
 		"--pretty",
 		"--remotes",
+		"--namespace=",
 		"--sparse",
 		"--tags",
 		"--topo-order",
@@ -577,6 +578,11 @@ int cmd_rev_parse(int argc, const char **argv, const char *prefix)
 				for_each_tag_ref(show_reference, NULL);
 				continue;
 			}
+			if (!prefixcmp(arg, "--namespace=")) {
+				set_for_each_namespace(arg + 12);
+				for_each_namespace_ref(show_reference, NULL);
+				continue;
+			}
 			if (!strcmp(arg, "--remotes")) {
 				for_each_remote_ref(show_reference, NULL);
 				continue;
diff --git a/refs.c b/refs.c
index 3e73a0a..ae3f1a4 100644
--- a/refs.c
+++ b/refs.c
@@ -7,6 +7,9 @@
 /* ISSYMREF=01 and ISPACKED=02 are public interfaces */
 #define REF_KNOWS_PEELED 04
 
+/* Current prefix namespace in use. NULL means none. */
+static char* prefix_namespace = NULL;
+
 struct ref_list {
 	struct ref_list *next;
 	unsigned char flag; /* ISSYMREF? ISPACKED? */
@@ -674,6 +677,36 @@ int for_each_replace_ref(each_ref_fn fn, void *cb_data)
 	return do_for_each_ref("refs/replace/", fn, 13, 0, cb_data);
 }
 
+void set_for_each_namespace(const char *ref_namespace)
+{
+	size_t alloclen, origlen;
+	if (prefix_namespace)
+		free(prefix_namespace);
+
+	/* Compute the length of true prefix. */
+	origlen = alloclen = strlen(ref_namespace);
+	if (*ref_namespace && ref_namespace[origlen - 1] != '/')
+		alloclen++;
+	if (prefixcmp(ref_namespace, "refs/"))
+		alloclen += 5;		/* 'refs/' */
+
+	/* Allocate and build it (assume alloclen is "small") */
+	prefix_namespace = xmalloc(alloclen + 1);
+	*prefix_namespace = 0;
+	if (prefixcmp(ref_namespace, "refs/"))
+		strcat(prefix_namespace, "refs/");
+	strcat(prefix_namespace, ref_namespace);
+	if (*ref_namespace && ref_namespace[origlen - 1] != '/')
+		strcat(prefix_namespace, "/");
+}
+
+int for_each_namespace_ref(each_ref_fn fn, void *cb_data)
+{
+	if (!prefix_namespace)
+		die("BUG: Call set_for_each_namespace() before for_each_namespace_ref()!");
+	return for_each_ref_in(prefix_namespace, fn, cb_data);
+}
+
 int for_each_rawref(each_ref_fn fn, void *cb_data)
 {
 	return do_for_each_ref("refs/", fn, 0,
diff --git a/refs.h b/refs.h
index e141991..be493ca 100644
--- a/refs.h
+++ b/refs.h
@@ -25,6 +25,15 @@ extern int for_each_tag_ref(each_ref_fn, void *);
 extern int for_each_branch_ref(each_ref_fn, void *);
 extern int for_each_remote_ref(each_ref_fn, void *);
 extern int for_each_replace_ref(each_ref_fn, void *);
+extern int for_each_namespace_ref(each_ref_fn, void *);
+
+/*
+ * Set namespace for_each_namespace_ref() operates in. Must be called before
+ * calling that function. Autoprepends 'refs/' if it is missing. Autoappends
+ * '/' if it is missing.
+ */
+void set_for_each_namespace(const char *ref_namespace);
+
 
 /* can be used to learn about broken ref and symref */
 extern int for_each_rawref(each_ref_fn, void *);
diff --git a/revision.c b/revision.c
index 25fa14d..9e1d960 100644
--- a/revision.c
+++ b/revision.c
@@ -1352,6 +1352,11 @@ int setup_revisions(int argc, const char **argv, struct rev_info *revs, const ch
 				handle_refs(revs, flags, for_each_remote_ref);
 				continue;
 			}
+			if (!prefixcmp(arg, "--namespace=")) {
+				set_for_each_namespace(arg + 12);
+				handle_refs(revs, flags, for_each_namespace_ref);
+				continue;
+			}
 			if (!strcmp(arg, "--reflog")) {
 				handle_reflog(revs, flags);
 				continue;
diff --git a/t/t6018-rev-list-namespace.sh b/t/t6018-rev-list-namespace.sh
new file mode 100755
index 0000000..f04bde1
--- /dev/null
+++ b/t/t6018-rev-list-namespace.sh
@@ -0,0 +1,103 @@
+#!/bin/sh
+
+test_description='rev-list/rev-parse --namespace'
+
+. ./test-lib.sh
+
+
+commit () {
+	test_tick &&
+	echo $1 > foo &&
+	git add foo &&
+	git commit -m "$1"
+}
+
+test_expect_success 'setup' '
+
+	commit master &&
+	git checkout -b subspace/one master
+	commit one &&
+	git checkout -b subspace/two master
+	commit two &&
+	git checkout -b other/three master
+	commit three &&
+	git checkout -b someref master
+	commit some &&
+	git checkout master
+	commit master2
+'
+
+test_expect_success 'rev-parse --namespace=refs/heads/subspace/' '
+
+	test 2 = $(git rev-parse --namespace=refs/heads/subspace/ | wc -l)
+
+'
+
+test_expect_success 'rev-parse --namespace=refs/heads/subspace' '
+
+	test 2 = $(git rev-parse --namespace=refs/heads/subspace | wc -l)
+
+'
+
+test_expect_success 'rev-parse --namespace=heads/subspace' '
+
+	test 2 = $(git rev-parse --namespace=heads/subspace | wc -l)
+
+'
+
+test_expect_success 'rev-parse --namespace=heads/subspace --namespace=heads/other' '
+
+	test 3 = $(git rev-parse --namespace=heads/subspace --namespace=heads/other | wc -l)
+
+'
+
+test_expect_success 'rev-parse --namespace=heads/someref master' '
+
+	test 1 = $(git rev-parse --namespace=heads/someref master | wc -l)
+
+'
+
+test_expect_success 'rev-parse --namespace=heads' '
+
+	test 4 = $(git rev-parse --namespace=heads | wc -l)
+
+'
+
+test_expect_success 'rev-list --namespace=refs/heads/subspace/' '
+
+	test 3 = $(git rev-list --namespace=refs/heads/subspace/ | wc -l)
+
+'
+
+test_expect_success 'rev-list --namespace=refs/heads/subspace' '
+
+	test 3 = $(git rev-list --namespace=refs/heads/subspace | wc -l)
+
+'
+
+test_expect_success 'rev-list --namespace=heads/subspace' '
+
+	test 3 = $(git rev-list --namespace=heads/subspace | wc -l)
+
+'
+
+test_expect_success 'rev-list --namespace=heads/someref master' '
+
+	test 2 = $(git rev-list --namespace=heads/someref master | wc -l)
+
+'
+
+test_expect_success 'rev-list --namespace=heads/subspace --namespace=heads/other' '
+
+	test 4 = $(git rev-list --namespace=heads/subspace --namespace=heads/other | wc -l)
+
+'
+
+test_expect_success 'rev-list --namespace=heads' '
+
+	test 5 = $(git rev-list --namespace=heads | wc -l)
+
+'
+
+
+test_done
-- 
1.6.6.199.gff4b0

Re: [PATCH] rev-parse --namespace

[Jeff King]

On Sun, Jan 17, 2010 at 03:45:31PM +0200, Ilari Liusvaara wrote:

> Add --namespace=<namespace> option to rev-parse and everything that
> accepts its options. This option matches all refs in some subnamespace
> of refs hierarchy, and is useful for selecting everything reachable from
> one or few, but not all remotes (--namespace=remotes/foo).

If I understand it correctly, isn't the same as

  git for-each-ref refs/remotes/foo

?

-Peff

Re: [PATCH] rev-parse --namespace

[Ilari Liusvaara]

On Sun, Jan 17, 2010 at 11:27:12AM -0500, Jeff King wrote:
> On Sun, Jan 17, 2010 at 03:45:31PM +0200, Ilari Liusvaara wrote:
> 
> > Add --namespace=<namespace> option to rev-parse and everything that
> > accepts its options. This option matches all refs in some subnamespace
> > of refs hierarchy, and is useful for selecting everything reachable from
> > one or few, but not all remotes (--namespace=remotes/foo).
> 
> If I understand it correctly, isn't the same as
> 
>   git for-each-ref refs/remotes/foo

Nope. Compare:

'git log --branches --not --namespace=remotes/origin' 

with whatever you would have to currently type...

-Ilari

Re: [PATCH] rev-parse --namespace

[Jeff King]

On Sun, Jan 17, 2010 at 06:40:57PM +0200, Ilari Liusvaara wrote:

> On Sun, Jan 17, 2010 at 11:27:12AM -0500, Jeff King wrote:
> > On Sun, Jan 17, 2010 at 03:45:31PM +0200, Ilari Liusvaara wrote:
> > 
> > > Add --namespace=<namespace> option to rev-parse and everything that
> > > accepts its options. This option matches all refs in some subnamespace
> > > of refs hierarchy, and is useful for selecting everything reachable from
> > > one or few, but not all remotes (--namespace=remotes/foo).
> > 
> > If I understand it correctly, isn't the same as
> > 
> >   git for-each-ref refs/remotes/foo
> 
> Nope. Compare:
> 
> 'git log --branches --not --namespace=remotes/origin' 
> 
> with whatever you would have to currently type...

OK, that makes sense and is actually useful. That is the sort of
motivation that should go in the commit message. Mentioning "rev-parse"
is a bit of a red herring.

As for the patch text itself, it looks correct, though I have a few
nits:

> diff --git a/Documentation/git-rev-parse.txt b/Documentation/git-rev-parse.txt
> index 82045a2..af4605a 100644
> --- a/Documentation/git-rev-parse.txt
> +++ b/Documentation/git-rev-parse.txt
> @@ -112,6 +112,10 @@ OPTIONS
>  --remotes::
>  	Show tag refs found in `$GIT_DIR/refs/remotes`.
>  
> +--namespace=namespace-prefix::
> +	Show refs found in `$GIT_DIR/namespace-prefix`. If namespace
> +	specified lacks leading 'refs/', it is automatically prepended.
> +

This is not a new problem you are introducing, as you are just following
the template of of --remotes and others above, but is "show" really the
right word? In the rev-list page these entries talk about "pretend as if
these refs were given on the command line". Isn't that also the case
here? If I say "git rev-parse --not --remotes" (or --namespace=), I will
get "^"-lines.

Also, I notice in the context that the remotes entry says "Show tag
refs" which is obviously wrong. Again, not your problem, but something
to clean up while in the area.

> +			if (!prefixcmp(arg, "--namespace=")) {
> +				set_for_each_namespace(arg + 12);
> +				for_each_namespace_ref(show_reference, NULL);
> +				continue;
> +			}

I was going to complain about the use of a global variable here when we
could simply pass the namespace into the function, but I see that in the
other call here:

> diff --git a/revision.c b/revision.c
> index 25fa14d..9e1d960 100644
> --- a/revision.c
> +++ b/revision.c
> @@ -1352,6 +1352,11 @@ int setup_revisions(int argc, const char **argv, struct rev_info *revs, const ch
>  				handle_refs(revs, flags, for_each_remote_ref);
>  				continue;
>  			}
> +			if (!prefixcmp(arg, "--namespace=")) {
> +				set_for_each_namespace(arg + 12);
> +				handle_refs(revs, flags, for_each_namespace_ref);
> +				continue;
> +			}

...that giving the for_each_namespace_ref function a different signature
than the other for_each_* functions would complicate things. OTOH,
handle_refs is only a 4 line helper to set up the callback struct, so
perhaps it is better to simply duplicate it rather than introduce a new
global.

Too bad we can't do currying in C. :)

> +void set_for_each_namespace(const char *ref_namespace)
> +{
> +	size_t alloclen, origlen;
> +	if (prefix_namespace)
> +		free(prefix_namespace);
> +
> +	/* Compute the length of true prefix. */
> +	origlen = alloclen = strlen(ref_namespace);
> +	if (*ref_namespace && ref_namespace[origlen - 1] != '/')
> +		alloclen++;
> +	if (prefixcmp(ref_namespace, "refs/"))
> +		alloclen += 5;		/* 'refs/' */
> +
> +	/* Allocate and build it (assume alloclen is "small") */
> +	prefix_namespace = xmalloc(alloclen + 1);
> +	*prefix_namespace = 0;
> +	if (prefixcmp(ref_namespace, "refs/"))
> +		strcat(prefix_namespace, "refs/");
> +	strcat(prefix_namespace, ref_namespace);
> +	if (*ref_namespace && ref_namespace[origlen - 1] != '/')
> +		strcat(prefix_namespace, "/");
> +}

Wouldn't this be much simpler and more readable using a strbuf? As in:

  strbuf_reset(&prefix_namespace);
  if (prefixcmp(ref_namespace, "refs/"))
    strbuf_addstr(&prefix_namespace, "refs/");
  strbuf_addstr(&prefix_namespace, ref_namespace);
  if (prefix_namespace.buf[prefix_namespace.len-1] != '/')
    strbuf_addch(&prefix_namespace, '/');

?

> +test_expect_success 'setup' '
> +
> +	commit master &&
> +	git checkout -b subspace/one master
> +	commit one &&
> +	git checkout -b subspace/two master
> +	commit two &&
> +	git checkout -b other/three master
> +	commit three &&
> +	git checkout -b someref master
> +	commit some &&
> +	git checkout master
> +	commit master2
> +'

Missing '&&' on the checkout lines?

> +test_expect_success 'rev-parse --namespace=refs/heads/subspace/' '
> +
> +	test 2 = $(git rev-parse --namespace=refs/heads/subspace/ | wc -l)
> +
> +'

This is perhaps a minor nit, but I really prefer to write this by
putting the expected output in a file and using test_cmp, because:

  1. You actually test that rev-parse exits correctly.

  2. You test that it actually produced the correct output, and not
     simply two lines which are presumably correct.

  3. If it _does_ fail, the output from test_cmp is a nicely readable
     diff between expected and actual output. Your test produces no
     output.

We also had some problems with different implementations of "wc"
producing different amounts of whitespace, but I don't think that is a
problem here since the shell should eat any whitespace outside of
quotation marks.

-Peff

Re: [PATCH] rev-parse --namespace

[Junio C Hamano]

Ilari Liusvaara <ilari.liusvaara@elisanet.fi> writes:

> 'git log --branches --not --namespace=remotes/origin' 

This sounds sensible; it essentially is a natural extention of the
existing --branches, --tags and --remotes options.  While I don't care too
much, people may want to have an even shorter name (perhaps --under=heads
or even --in=tags.

In any case, we would want to have your "log" command line above both in
the proposed commit log message and the documentation in the Examples
section, given that this is not immediately obvious to even veterans like
Peff and I; it didn't "click" for me until I saw the follow-up exchange
between you two.