A shallow commit is a commit which has parents, which in turn are
"grafted away", i.e. the commit appears as if it were a root.
Since these shallow commits should not be edited by the user, but
only by core git, they are recorded in the file $GIT_DIR/shallow.
A repository containing shallow commits is called shallow.
The advantage of a shallow repository is that even if the upstream
contains lots of history, your local (shallow) repository needs not
occupy much disk space.
The disadvantage is that you might miss a merge base when pulling
some remote branch.
Signed-off-by: Johannes Schindelin <johannes.schindelin@xxxxxx>
---
Makefile | 2 +-
commit.c | 21 ++++++++++++
commit.h | 8 ++++-
fetch-pack.c | 4 ++
shallow.c | 97 +++++++++++++++++++++++++++++++++++++++++++++++++++++++++
upload-pack.c | 22 ++++++++++++-
6 files changed, 150 insertions(+), 4 deletions(-)
diff --git a/Makefile b/Makefile
index 28a5d91..5f57aad 100644
--- a/Makefile
+++ b/Makefile
@@ -263,7 +263,7 @@ LIB_OBJS = \
fetch-clone.o revision.o pager.o tree-walk.o xdiff-interface.o \
write_or_die.o trace.o list-objects.o grep.o \
alloc.o merge-file.o path-list.o help.o unpack-trees.o $(DIFF_OBJS) \
- color.o wt-status.o archive-zip.o archive-tar.o
+ color.o wt-status.o archive-zip.o archive-tar.o shallow.o
BUILTIN_OBJS = \
builtin-add.o \
diff --git a/commit.c b/commit.c
index a6d543e..bffa278 100644
--- a/commit.c
+++ b/commit.c
@@ -1,6 +1,7 @@
#include "cache.h"
#include "tag.h"
#include "commit.h"
+#include "pkt-line.h"
int save_commit_buffer = 1;
@@ -221,6 +222,8 @@ static void prepare_commit_graft(void)
return;
graft_file = get_graft_file();
read_graft_file(graft_file);
+ /* make sure shallows are read */
+ is_repository_shallow();
commit_graft_prepared = 1;
}
@@ -234,6 +237,24 @@ static struct commit_graft *lookup_commi
return commit_graft[pos];
}
+int write_shallow_commits(int fd, int use_pack_protocol)
+{
+ int i, count = 0;
+ for (i = 0; i < commit_graft_nr; i++)
+ if (commit_graft[i]->nr_parent < 0) {
+ const char *hex =
+ sha1_to_hex(commit_graft[i]->sha1);
+ count++;
+ if (use_pack_protocol)
+ packet_write(fd, "shallow %s", hex);
+ else {
+ write(fd, hex, 40);
+ write(fd, "\n", 1);
+ }
+ }
+ return count;
+}
+
int parse_commit_buffer(struct commit *item, void *buffer, unsigned long size)
{
char *tail = buffer;
diff --git a/commit.h b/commit.h
index fc13de9..c559510 100644
--- a/commit.h
+++ b/commit.h
@@ -97,7 +97,7 @@ void sort_in_topological_order_fn(struct
struct commit_graft {
unsigned char sha1[20];
- int nr_parent;
+ int nr_parent; /* < 0 if shallow commit */
unsigned char parent[FLEX_ARRAY][20]; /* more */
};
@@ -107,4 +107,10 @@ int read_graft_file(const char *graft_fi
extern struct commit_list *get_merge_bases(struct commit *rev1, struct commit *rev2, int cleanup);
+extern int register_shallow(const unsigned char *sha1);
+extern int write_shallow_commits(int fd, int use_pack_protocol);
+extern int is_repository_shallow();
+extern struct commit_list *get_shallow_commits(struct object_array *heads,
+ int depth);
+
#endif /* COMMIT_H */
diff --git a/fetch-pack.c b/fetch-pack.c
index 36ea092..488adc9 100644
--- a/fetch-pack.c
+++ b/fetch-pack.c
@@ -177,6 +177,8 @@ static int find_common(int fd[2], unsign
packet_write(fd[1], "want %s\n", sha1_to_hex(remote));
fetching++;
}
+ if (is_repository_shallow())
+ write_shallow_commits(fd[1], 1);
packet_flush(fd[1]);
if (!fetching)
return 1;
@@ -423,6 +425,8 @@ static int fetch_pack(int fd[2], int nr_
int status;
get_remote_heads(fd[0], &ref, 0, NULL, 0);
+ if (is_repository_shallow() && !server_supports("shallow"))
+ die("Server does not support shallow clients");
if (server_supports("multi_ack")) {
if (verbose)
fprintf(stderr, "Server supports multi_ack\n");
diff --git a/shallow.c b/shallow.c
new file mode 100644
index 0000000..3cf2127
--- /dev/null
+++ b/shallow.c
@@ -0,0 +1,97 @@
+#include "cache.h"
+#include "commit.h"
+
+static int is_shallow = -1;
+
+int register_shallow(const unsigned char *sha1)
+{
+ struct commit_graft *graft =
+ xmalloc(sizeof(struct commit_graft));
+ struct commit *commit = lookup_commit(sha1);
+
+ hashcpy(graft->sha1, sha1);
+ graft->nr_parent = -1;
+ if (commit && commit->object.parsed)
+ commit->parents = NULL;
+ return register_commit_graft(graft, 0);
+}
+
+int is_repository_shallow()
+{
+ FILE *fp;
+ char buf[1024];
+
+ if (is_shallow >= 0)
+ return is_shallow;
+
+ fp = fopen(git_path("shallow"), "r");
+ if (!fp) {
+ is_shallow = 0;
+ return is_shallow;
+ }
+ is_shallow = 1;
+
+ while (fgets(buf, sizeof(buf), fp)) {
+ unsigned char sha1[20];
+ if (get_sha1_hex(buf, sha1))
+ die("bad shallow line: %s", buf);
+ register_shallow(sha1);
+ }
+ fclose(fp);
+ return is_shallow;
+}
+
+struct commit_list *get_shallow_commits(struct object_array *heads, int depth)
+{
+ int i = 0, cur_depth = 0;
+ struct commit_list *result = NULL;
+ struct object_array stack = {0, 0, NULL};
+ struct commit *commit = NULL;
+
+ while (commit || i < heads->nr || stack.nr) {
+ struct commit_list *p;
+ if (!commit) {
+ if (i < heads->nr) {
+ commit = (struct commit *)
+ heads->objects[i++].item;
+ if (commit->object.type != OBJ_COMMIT) {
+ commit = NULL;
+ continue;
+ }
+ commit->util = xcalloc(1, sizeof(int));
+ cur_depth = 0;
+ } else {
+ commit = (struct commit *)
+ stack.objects[--stack.nr].item;
+ cur_depth = *(int *)commit->util;
+ }
+ }
+ parse_commit(commit);
+ cur_depth++;
+ for (p = commit->parents, commit = NULL; p; p = p->next) {
+ if (!p->item->util) {
+ int *pointer = xmalloc(sizeof(int));
+ p->item->util = pointer;
+ *pointer = cur_depth;
+ } else {
+ int *pointer = p->item->util;
+ if (cur_depth >= *pointer)
+ continue;
+ *pointer = cur_depth;
+ }
+ if (cur_depth < depth) {
+ if (p->next)
+ add_object_array(&p->item->object,
+ NULL, &stack);
+ else {
+ commit = p->item;
+ cur_depth = *(int *)commit->util;
+ }
+ } else
+ commit_list_insert(p->item, &result);
+ }
+ }
+
+ return result;
+}
+
diff --git a/upload-pack.c b/upload-pack.c
index 7f7df2a..8dd6121 100644
--- a/upload-pack.c
+++ b/upload-pack.c
@@ -486,6 +486,7 @@ static int get_common_commits(void)
static void receive_needs(void)
{
+ struct object_array shallows = {0, 0, NULL};
static char line[1000];
int len;
@@ -495,8 +496,19 @@ static void receive_needs(void)
len = packet_read_line(0, line, sizeof(line));
reset_timeout();
if (!len)
- return;
+ break;
+ if (!strncmp("shallow ", line, 8)) {
+ unsigned char sha1[20];
+ struct object *object;
+ if (get_sha1(line + 8, sha1))
+ die("invalid shallow line: %s", line);
+ object = parse_object(sha1);
+ if (!object)
+ die("did not find object for %s", line);
+ add_object_array(object, NULL, &shallows);
+ continue;
+ }
if (strncmp("want ", line, 5) ||
get_sha1_hex(line+5, sha1_buf))
die("git-upload-pack: protocol error, "
@@ -528,11 +540,17 @@ static void receive_needs(void)
add_object_array(o, NULL, &want_obj);
}
}
+ if (shallows.nr > 0) {
+ int i;
+ for (i = 0; i < shallows.nr; i++)
+ register_shallow(shallows.objects[i].item->sha1);
+ }
}
static int send_ref(const char *refname, const unsigned char *sha1, int flag, void *cb_data)
{
- static const char *capabilities = "multi_ack thin-pack side-band side-band-64k ofs-delta";
+ static const char *capabilities = "multi_ack thin-pack side-band"
+ " side-band-64k ofs-delta shallow";
struct object *o = parse_object(sha1);
if (!o)
--
1.4.3.3.gca42
-
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