Allow fast-import frontends to reload the marks table

I'm giving fast-import a lesson on how to reload the marks table
using the same format it outputs with --export-marks.  This way
a frontend can reload the marks table from a prior import, making
incremental imports less painful.

Signed-off-by: Shawn O. Pearce <spearce@spearce.org>

diff --git a/Documentation/git-fast-import.txt b/Documentation/git-fast-import.txt
index 77a14bb076b6d8be624345ee10e4bd14cfb2c359..7e3d2b1a96a3ef6819a0f3ccebf8f717de9d32dc 100644 (file)
--- a/Documentation/git-fast-import.txt
+++ b/Documentation/git-fast-import.txt
@@ -62,7 +62,18 @@ OPTIONS
        Dumps the internal marks table to <file> when complete.
        Marks are written one per line as `:markid SHA-1`.
        Frontends can use this file to validate imports after they
-       have been completed.
+       have been completed, or to save the marks table across
+       incremental runs.  As <file> is only opened and truncated
+       at checkpoint (or completion) the same path can also be
+       safely given to \--import-marks.
+
+--import-marks=<file>::
+       Before processing any input, load the marks specified in
+       <file>.  The input file must exist, must be readable, and
+       must use the same format as produced by \--export-marks.
+       Multiple options may be supplied to import more than one
+       set of marks.  If a mark is defined to different values,
+       the last file wins.
 
 --export-pack-edges=<file>::
        After creating a packfile, print a line of data to

diff --git a/fast-import.c b/fast-import.c
index a09221242e3866d8b5f01d21ca2e27adbb1558e4..fbed8e4e89cb5cd8bb1d8f666de8a19c71912136 100644 (file)
--- a/fast-import.c
+++ b/fast-import.c
@@ -1997,6 +1997,40 @@ static void cmd_checkpoint(void)
        read_next_command();
 }
 
+static void import_marks(const char *input_file)
+{
+       char line[512];
+       FILE *f = fopen(input_file, "r");
+       if (!f)
+               die("cannot read %s: %s", input_file, strerror(errno));
+       while (fgets(line, sizeof(line), f)) {
+               uintmax_t mark;
+               char *end;
+               unsigned char sha1[20];
+               struct object_entry *e;
+
+               end = strchr(line, '\n');
+               if (line[0] != ':' || !end)
+                       die("corrupt mark line: %s", line);
+               *end = 0;
+               mark = strtoumax(line + 1, &end, 10);
+               if (!mark || end == line + 1
+                       || *end != ' ' || get_sha1(end + 1, sha1))
+                       die("corrupt mark line: %s", line);
+               e = find_object(sha1);
+               if (!e) {
+                       enum object_type type = sha1_object_info(sha1, NULL);
+                       if (type < 0)
+                               die("object not found: %s", sha1_to_hex(sha1));
+                       e = insert_object(sha1);
+                       e->type = type;
+                       e->pack_id = MAX_PACK_ID;
+               }
+               insert_mark(mark, e);
+       }
+       fclose(f);
+}
+
 static const char fast_import_usage[] =
 "git-fast-import [--date-format=f] [--max-pack-size=n] [--depth=n] [--active-branches=n] [--export-marks=marks.file]";
 
@@ -2034,6 +2068,8 @@ int main(int argc, const char **argv)
                        max_depth = strtoul(a + 8, NULL, 0);
                else if (!prefixcmp(a, "--active-branches="))
                        max_active_branches = strtoul(a + 18, NULL, 0);
+               else if (!prefixcmp(a, "--import-marks="))
+                       import_marks(a + 15);
                else if (!prefixcmp(a, "--export-marks="))
                        mark_file = a + 15;
                else if (!prefixcmp(a, "--export-pack-edges=")) {

diff --git a/t/t9300-fast-import.sh b/t/t9300-fast-import.sh
index 970d683650f5ee6b99a07ff10063710292b28ed1..2e1a09ff2db29421629b038a3374449c49bdc79d 100755 (executable)
--- a/t/t9300-fast-import.sh
+++ b/t/t9300-fast-import.sh
@@ -111,6 +111,14 @@ test_expect_success \
        'A: verify marks output' \
        'diff -u expect marks.out'
 
+test_expect_success \
+       'A: verify marks import' \
+       'git-fast-import \
+               --import-marks=marks.out \
+               --export-marks=marks.new \
+               </dev/null &&
+       diff -u expect marks.new'
+
 ###
 ### series B
 ###