Add a --stdin signature to read update instructions from standard input
and apply multiple ref updates together.  Use an input format that
supports any update that could be specified via the command-line,
including object names like "branch:path with space".

Signed-off-by: Brad King <brad.k...@kitware.com>
---
 Documentation/git-update-ref.txt |  22 +++++-
 builtin/update-ref.c             | 144 ++++++++++++++++++++++++++++++++++++++-
 2 files changed, 164 insertions(+), 2 deletions(-)

diff --git a/Documentation/git-update-ref.txt b/Documentation/git-update-ref.txt
index 0df13ff..11dd9d3 100644
--- a/Documentation/git-update-ref.txt
+++ b/Documentation/git-update-ref.txt
@@ -8,7 +8,7 @@ git-update-ref - Update the object name stored in a ref safely
 SYNOPSIS
 --------
 [verse]
-'git update-ref' [-m <reason>] (-d <ref> [<oldvalue>] | [--no-deref] <ref> 
<newvalue> [<oldvalue>])
+'git update-ref' [-m <reason>] (-d <ref> [<oldvalue>] | [--no-deref] <ref> 
<newvalue> [<oldvalue>] | --stdin)
 
 DESCRIPTION
 -----------
@@ -58,6 +58,26 @@ archive by creating a symlink tree).
 With `-d` flag, it deletes the named <ref> after verifying it
 still contains <oldvalue>.
 
+With `--stdin`, update-ref reads instructions from standard input and
+performs all modifications together.  Empty lines are ignored.
+Each non-empty line is parsed as whitespace-separated arguments.
+Quote arguments containing whitespace as if in C source code.
+Specify updates with lines of the form:
+
+       [--no-deref] [--] <ref> <newvalue> [<oldvalue>]
+
+Lines of any other format or a repeated <ref> produce an error.
+Specify a zero <newvalue> to delete a ref and/or a zero <oldvalue>
+to make sure that a ref not exist.  Use either 40 "0" or the
+empty string (written as "") to specify a zero value.  Use `-z`
+to specify input with no whitespace, quoting, or escaping, and
+terminate each argument by NUL and each line by LF NUL.
+
+If all <ref>s can be locked with matching <oldvalue>s
+simultaneously, all modifications are performed.  Otherwise, no
+modifications are performed.  Note that while each individual
+<ref> is updated or deleted atomically, a concurrent reader may
+still see a subset of the modifications.
 
 Logging Updates
 ---------------
diff --git a/builtin/update-ref.c b/builtin/update-ref.c
index 51d2684..9c348fb 100644
--- a/builtin/update-ref.c
+++ b/builtin/update-ref.c
@@ -2,23 +2,152 @@
 #include "refs.h"
 #include "builtin.h"
 #include "parse-options.h"
+#include "quote.h"
+#include "argv-array.h"
 
 static const char * const git_update_ref_usage[] = {
        N_("git update-ref [options] -d <refname> [<oldval>]"),
        N_("git update-ref [options]    <refname> <newval> [<oldval>]"),
+       N_("git update-ref [options] --stdin [-z]"),
        NULL
 };
 
+static int updates_alloc;
+static int updates_count;
+static const struct ref_update **updates;
+
+static void update_refs_stdin(int argc, const char **argv)
+{
+       struct ref_update *update;
+
+       /* Skip blank lines */
+       if (!argc)
+               return;
+
+       /* Allocate and zero-init a struct ref_update */
+       update = xcalloc(1, sizeof(*update));
+       ALLOC_GROW(updates, updates_count+1, updates_alloc);
+       updates[updates_count++] = update;
+
+       /* Process options */
+       while (argc > 0 && argv[0][0] == '-') {
+               const char *arg = argv[0];
+               --argc;
+               ++argv;
+               if (!strcmp(arg, "--no-deref"))
+                       update->flags |= REF_NODEREF;
+               else if (!strcmp(arg, "--"))
+                       break;
+               else
+                       die("unknown option %s", arg);
+       }
+
+       /* Set the update ref_name */
+       if (argc < 1)
+               die("input line with no ref!");
+       if (check_refname_format(argv[0], REFNAME_ALLOW_ONELEVEL))
+               die("invalid ref format: %s", argv[0]);
+       update->ref_name = xstrdup(argv[0]);
+
+       /* Set the update new_sha1 and, if specified, old_sha1 */
+       if (argc < 2)
+               die("missing new value for ref %s", update->ref_name);
+       if (*argv[1] && get_sha1(argv[1], update->new_sha1))
+               die("invalid new value for ref %s: %s",
+                   update->ref_name, argv[1]);
+       if (argc >= 3) {
+               update->have_old = 1;
+               if (*argv[2] && get_sha1(argv[2], update->old_sha1))
+                       die("invalid old value for ref %s: %s",
+                           update->ref_name, argv[2]);
+       }
+
+       if (argc > 3)
+               die("too many arguments for ref %s", update->ref_name);
+}
+
+static const char *update_refs_stdin_parse_arg(const char *next,
+                                              struct strbuf *arg)
+{
+       /* Skip leading whitespace */
+       while (isspace(*next))
+               ++next;
+
+       /* Return NULL when no argument is found */
+       if (!*next)
+               return NULL;
+
+       /* Parse the argument */
+       strbuf_reset(arg);
+       if (*next == '"') {
+               if (unquote_c_style(arg, next, &next))
+                       die("badly quoted argument: %s", next);
+               return next;
+       }
+       while (*next && !isspace(*next))
+               strbuf_addch(arg, *next++);
+       return next;
+}
+
+static void update_refs_stdin_parse_line(const char *next)
+{
+       struct strbuf arg = STRBUF_INIT;
+       static struct argv_array args = ARGV_ARRAY_INIT;
+
+       /* Parse arguments on this line */
+       while ((next = update_refs_stdin_parse_arg(next, &arg)) != NULL)
+               argv_array_push(&args, arg.buf);
+
+       /* Process this command */
+       update_refs_stdin(args.argc, args.argv);
+
+       argv_array_clear(&args);
+       strbuf_release(&arg);
+}
+
+static void update_refs_stdin_read_n()
+{
+       struct strbuf line = STRBUF_INIT;
+
+       while (strbuf_getline(&line, stdin, '\n') != EOF)
+               update_refs_stdin_parse_line(line.buf);
+
+       strbuf_release(&line);
+}
+
+static void update_refs_stdin_read_z()
+{
+       struct strbuf arg = STRBUF_INIT;
+       static struct argv_array args = ARGV_ARRAY_INIT;
+
+       /* Process NUL-terminated arguments with commands ending in LF */
+       while (strbuf_getline(&arg, stdin, '\0') != EOF) {
+               if (!strcmp(arg.buf, "\n")) {
+                       update_refs_stdin(args.argc, args.argv);
+                       argv_array_clear(&args);
+               } else {
+                       argv_array_push(&args, arg.buf);
+               }
+       }
+
+       if (args.argc > 0)
+               die("unterminated -z input sequence");
+
+       strbuf_release(&arg);
+}
+
 int cmd_update_ref(int argc, const char **argv, const char *prefix)
 {
        const char *refname, *oldval, *msg = NULL;
        unsigned char sha1[20], oldsha1[20];
-       int delete = 0, no_deref = 0, flags = 0;
+       int delete = 0, no_deref = 0, read_stdin = 0, end_null = 0, flags = 0;
        struct option options[] = {
                OPT_STRING( 'm', NULL, &msg, N_("reason"), N_("reason of the 
update")),
                OPT_BOOLEAN('d', NULL, &delete, N_("delete the reference")),
+               OPT_BOOLEAN('z', NULL, &end_null, N_("stdin has NUL-terminated 
arguments")),
                OPT_BOOLEAN( 0 , "no-deref", &no_deref,
                                        N_("update <refname> not the one it 
points to")),
+               OPT_BOOLEAN( 0 , "stdin", &read_stdin, N_("read updates from 
stdin")),
                OPT_END(),
        };
 
@@ -28,6 +157,19 @@ int cmd_update_ref(int argc, const char **argv, const char 
*prefix)
        if (msg && !*msg)
                die("Refusing to perform update with empty message.");
 
+       if (read_stdin) {
+               if (delete || no_deref || argc > 0)
+                       usage_with_options(git_update_ref_usage, options);
+               if (end_null)
+                       update_refs_stdin_read_z();
+               else
+                       update_refs_stdin_read_n();
+               return update_refs(msg, updates, updates_count, DIE_ON_ERR);
+       }
+
+       if (end_null)
+               usage_with_options(git_update_ref_usage, options);
+
        if (delete) {
                if (argc < 1 || argc > 2)
                        usage_with_options(git_update_ref_usage, options);
-- 
1.8.4.rc3

--
To unsubscribe from this list: send the line "unsubscribe git" in
the body of a message to majord...@vger.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html

Reply via email to