[PATCH 3/4] pack v4: cache flattened v4 trees in delta base cache
Signed-off-by: Nguyễn Thái Ngọc Duy <pclouds@gmail.com>
---
The memmove in pv4_get_tree() may look inefficient. I added a
heuristics to avoid moving if nb_entries takes 2 bytes (most common,
I think), but it does not improve much. So memmove() is probably ok.
packv4-parse.c | 60 +++++++++++++++++++++++++++++++++++++++++++++++++++-------
packv4-parse.h | 3 ++-
sha1_file.c | 8 +++++++-
3 files changed, 62 insertions(+), 9 deletions(-)
diff --git a/packv4-parse.c b/packv4-parse.c
index ae3e6a5..5002f42 100644
--- a/packv4-parse.c
+++ b/packv4-parse.c
@@ -406,7 +406,10 @@ static int tree_entry_prefix(unsigned char *buf, unsigned long size,
static int decode_entries(struct packed_git *p, struct pack_window **w_curs,
off_t offset, unsigned int start, unsigned int count,
- unsigned char **dstp, unsigned long *sizep, int hdr)
+ unsigned char **dstp, unsigned long *sizep,
+ unsigned char **v4_dstp, unsigned long *v4_sizep,
+ unsigned int *v4_entries,
+ int hdr)
{
unsigned long avail;
unsigned int nb_entries;
@@ -422,10 +425,18 @@ static int decode_entries(struct packed_git *p, struct pack_window **w_curs,
if (++scp - src >= avail - 20)
return -1;
/* is this a canonical tree object? */
- if ((*scp & 0xf) == OBJ_TREE)
+ if ((*scp & 0xf) == OBJ_TREE) {
+ /*
+ * we could try to convert to v4 tree before
+ * giving up, provided that the number of
+ * inconvertible trees is small. But that's
+ * for later.
+ */
+ *v4_dstp = NULL;
return copy_canonical_tree_entries(p, offset,
start, count,
dstp, sizep);
+ }
/* let's still make sure this is actually a pv4 tree */
if ((*scp++ & 0xf) != OBJ_PV4_TREE)
return -1;
@@ -484,6 +495,16 @@ static int decode_entries(struct packed_git *p, struct pack_window **w_curs,
*dstp += len + 20;
*sizep -= len + 20;
count--;
+ if (*v4_dstp) {
+ if (scp - src > *v4_sizep)
+ *v4_dstp = NULL;
+ else {
+ memcpy(*v4_dstp, src, scp - src);
+ *v4_dstp += scp - src;
+ *v4_sizep -= scp - src;
+ (*v4_entries)++;
+ }
+ }
} else if (what & 1) {
/*
* Copy from another tree object.
@@ -537,7 +558,8 @@ static int decode_entries(struct packed_git *p, struct pack_window **w_curs,
count -= copy_count;
ret = decode_entries(p, w_curs,
copy_objoffset, copy_start, copy_count,
- dstp, sizep, 1);
+ dstp, sizep, v4_dstp, v4_sizep,
+ v4_entries, 1);
if (ret)
return ret;
/* force pack window readjustment */
@@ -554,11 +576,13 @@ static int decode_entries(struct packed_git *p, struct pack_window **w_curs,
}
void *pv4_get_tree(struct packed_git *p, struct pack_window **w_curs,
- off_t offset, unsigned long size)
+ off_t offset, unsigned long size,
+ void **v4_data, unsigned long *v4_size)
{
- unsigned long avail;
- unsigned int nb_entries;
+ unsigned long avail, v4_max_size;
+ unsigned int nb_entries, v4_entries;
unsigned char *dst, *dcp;
+ unsigned char *v4_dst, *v4_dcp;
const unsigned char *src, *scp;
int ret;
@@ -570,11 +594,33 @@ void *pv4_get_tree(struct packed_git *p, struct pack_window **w_curs,
dst = xmallocz(size);
dcp = dst;
- ret = decode_entries(p, w_curs, offset, 0, nb_entries, &dcp, &size, 0);
+ if (v4_data) {
+ /*
+ * v4 can't be larger than canonical, so "size" should
+ * be enough
+ */
+ v4_max_size = size;
+ v4_dst = v4_dcp = xmallocz(v4_max_size);
+ v4_entries = 0;
+ }
+ ret = decode_entries(p, w_curs, offset, 0, nb_entries,
+ &dcp, &size,
+ v4_data ? &v4_dcp : NULL, &v4_max_size,
+ &v4_entries, 0);
if (ret < 0 || size != 0) {
free(dst);
+ free(v4_dst);
return NULL;
}
+ if (v4_data && v4_dcp) {
+ unsigned char hdr[10];
+ int len = encode_varint(v4_entries, hdr);
+ memmove(v4_dst + len, v4_dst, v4_dcp - v4_dst);
+ memcpy(v4_dst, hdr, len);
+ *v4_data = v4_dst;
+ *v4_size = len + v4_dcp - v4_dst;
+ } else
+ free(v4_dst);
return dst;
}
diff --git a/packv4-parse.h b/packv4-parse.h
index d674a3f..647b73c 100644
--- a/packv4-parse.h
+++ b/packv4-parse.h
@@ -20,6 +20,7 @@ const unsigned char *get_sha1ref(struct packed_git *p,
void *pv4_get_commit(struct packed_git *p, struct pack_window **w_curs,
off_t offset, unsigned long size);
void *pv4_get_tree(struct packed_git *p, struct pack_window **w_curs,
- off_t offset, unsigned long size);
+ off_t offset, unsigned long size,
+ void **v4_data, unsigned long *v4_size);
#endif
diff --git a/sha1_file.c b/sha1_file.c
index 03c66bb..b176316 100644
--- a/sha1_file.c
+++ b/sha1_file.c
@@ -2103,6 +2103,8 @@ void *unpack_entry(struct packed_git *p, off_t obj_offset,
struct unpack_entry_stack_ent *delta_stack = small_delta_stack;
int delta_stack_nr = 0, delta_stack_alloc = UNPACK_ENTRY_STACK_PREALLOC;
int base_from_cache = 0;
+ void *v4_data;
+ unsigned long v4_size;
if (log_pack_access != no_log_pack_access)
write_pack_access_log(p, obj_offset);
@@ -2181,7 +2183,11 @@ void *unpack_entry(struct packed_git *p, off_t obj_offset,
type -= 8;
break;
case OBJ_PV4_TREE:
- data = pv4_get_tree(p, &w_curs, curpos, size);
+ v4_data = NULL;
+ data = pv4_get_tree(p, &w_curs, curpos, size, &v4_data, &v4_size);
+ if (v4_data)
+ add_delta_base_cache(p, obj_offset, v4_data,
+ size, v4_size, type);
type -= 8;
break;
case OBJ_COMMIT:
--
1.8.2.83.gc99314b
Nguyễn Thái Ngọc Duy <pclouds@gmail.com>