rev-list: support delimiting objects with NUL bytes

When walking objects, git-rev-list(1) prints each object entry on a
separate line. Some options, such as `--objects`, may print additional
information about tree and blob object on the same line in the form:

        $ git rev-list --objects <rev>
        <tree/blob oid> SP [<path>] LF

Note that in this form the SP is appended regardless of whether the tree
or blob object has path information available. Paths containing a
newline are also truncated at the newline.

Introduce the `-z` option for git-rev-list(1) which reformats the output
to use NUL-delimiters between objects and associated info in the
following form:

        $ git rev-list -z --objects <rev>
        <oid> NUL [path=<path> NUL]

In this form, the start of each record is signaled by an OID entry that
is all hexidecimal and does not contain any '='. Additional path info
from `--objects` is appended to the record as a token/value pair
`path=<path>` as-is without any truncation.

For now, the `--objects` flag is the only options that can be used in
combination with `-z`. In a subsequent commit, NUL-delimited support for
other options is added. Other options that do not make sense when used
in combination with `-z` are rejected.

Signed-off-by: Justin Tobler <jltobler@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

diff --git a/Documentation/rev-list-options.adoc b/Documentation/rev-list-options.adoc
index 785c0786e0cf2c141ac40df82e675e4cd5fe74c8..aef83813b80955b08949d02a7e3bf316258fb30b 100644 (file)
--- a/Documentation/rev-list-options.adoc
+++ b/Documentation/rev-list-options.adoc
@@ -361,6 +361,27 @@ ifdef::git-rev-list[]
 --progress=<header>::
        Show progress reports on stderr as objects are considered. The
        `<header>` text will be printed with each progress update.
+
+-z::
+       Instead of being newline-delimited, each outputted object and its
+       accompanying metadata is delimited using NUL bytes. Output is printed
+       in the following form:
++
+-----------------------------------------------------------------------
+<OID> NUL [<token>=<value> NUL]...
+-----------------------------------------------------------------------
++
+Additional object metadata, such as object paths, is printed using the
+`<token>=<value>` form. Token values are printed as-is without any
+encoding/truncation. An OID entry never contains a '=' character and thus
+is used to signal the start of a new object record. Examples:
++
+-----------------------------------------------------------------------
+<OID> NUL
+<OID> NUL path=<path> NUL
+-----------------------------------------------------------------------
++
+This mode is only compatible with the `--objects` output option.
 endif::git-rev-list[]
 
 History Simplification

diff --git a/builtin/rev-list.c b/builtin/rev-list.c
index 04d9c893b5dcc5096e5534d234f0feb935c40508..17de99d9cadf00949103b6f84d6358e2c34de1e3 100644 (file)
--- a/builtin/rev-list.c
+++ b/builtin/rev-list.c
@@ -65,6 +65,7 @@ static const char rev_list_usage[] =
 "    --abbrev-commit\n"
 "    --left-right\n"
 "    --count\n"
+"    -z\n"
 "  special purpose:\n"
 "    --bisect\n"
 "    --bisect-vars\n"
@@ -97,6 +98,9 @@ static int arg_show_object_names = 1;
 
 #define DEFAULT_OIDSET_SIZE     (16*1024)
 
+static char line_term = '\n';
+static char info_term = ' ';
+
 static int show_disk_usage;
 static off_t total_disk_usage;
 static int human_readable;
@@ -264,7 +268,7 @@ static void show_commit(struct commit *commit, void *data)
        if (revs->commit_format == CMIT_FMT_ONELINE)
                putchar(' ');
        else if (revs->include_header)
-               putchar('\n');
+               putchar(line_term);
 
        if (revs->verbose_header) {
                struct strbuf buf = STRBUF_INIT;
@@ -361,12 +365,16 @@ static void show_object(struct object *obj, const char *name, void *cb_data)
        printf("%s", oid_to_hex(&obj->oid));
 
        if (arg_show_object_names) {
-               putchar(' ');
-               for (const char *p = name; *p && *p != '\n'; p++)
-                       putchar(*p);
+               if (line_term) {
+                       putchar(info_term);
+                       for (const char *p = name; *p && *p != '\n'; p++)
+                               putchar(*p);
+               } else if (*name) {
+                       printf("%cpath=%s", info_term, name);
+               }
        }
 
-       putchar('\n');
+       putchar(line_term);
 }
 
 static void show_edge(struct commit *commit)
@@ -642,6 +650,9 @@ int cmd_rev_list(int argc,
                        revs.exclude_promisor_objects = 1;
                } else if (skip_prefix(arg, "--missing=", &arg)) {
                        parse_missing_action_value(arg);
+               } else if (!strcmp(arg, "-z")) {
+                       line_term = '\0';
+                       info_term = '\0';
                }
        }
 
@@ -757,6 +768,20 @@ int cmd_rev_list(int argc,
                usage(rev_list_usage);
 
        }
+
+       /*
+        * Reject options currently incompatible with -z. For some options, this
+        * is not an inherent limitation and support may be implemented in the
+        * future.
+        */
+       if (!line_term) {
+               if (revs.graph || revs.verbose_header || show_disk_usage ||
+                   info.show_timestamp || info.header_prefix || bisect_list ||
+                   use_bitmap_index || revs.edge_hint || revs.left_right ||
+                   revs.cherry_mark || arg_missing_action || revs.boundary)
+                       die(_("-z option used with unsupported option"));
+       }
+
        if (revs.commit_format != CMIT_FMT_USERFORMAT)
                revs.include_header = 1;
        if (revs.commit_format != CMIT_FMT_UNSPECIFIED) {

diff --git a/t/t6000-rev-list-misc.sh b/t/t6000-rev-list-misc.sh
index 6289a2e8b03890ded5863f3472e469c28cb3034a..886e2fc710b66f865cb727f7e0c5f46b51043e8d 100755 (executable)
--- a/t/t6000-rev-list-misc.sh
+++ b/t/t6000-rev-list-misc.sh
@@ -182,4 +182,39 @@ test_expect_success 'rev-list --unpacked' '
        test_cmp expect actual
 '
 
+test_expect_success 'rev-list -z' '
+       test_when_finished rm -rf repo &&
+
+       git init repo &&
+       test_commit -C repo 1 &&
+       test_commit -C repo 2 &&
+
+       oid1=$(git -C repo rev-parse HEAD~) &&
+       oid2=$(git -C repo rev-parse HEAD) &&
+
+       printf "%s\0%s\0" "$oid2" "$oid1" >expect &&
+       git -C repo rev-list -z HEAD >actual &&
+
+       test_cmp expect actual
+'
+
+test_expect_success 'rev-list -z --objects' '
+       test_when_finished rm -rf repo &&
+
+       git init repo &&
+       test_commit -C repo 1 &&
+       test_commit -C repo 2 &&
+
+       oid1=$(git -C repo rev-parse HEAD:1.t) &&
+       oid2=$(git -C repo rev-parse HEAD:2.t) &&
+       path1=1.t &&
+       path2=2.t &&
+
+       printf "%s\0path=%s\0%s\0path=%s\0" "$oid1" "$path1" "$oid2" "$path2" \
+               >expect &&
+       git -C repo rev-list -z --objects HEAD:1.t HEAD:2.t >actual &&
+
+       test_cmp expect actual
+'
+
 test_done