While reviewing the pack v4 thin support Ive realized that some base
tree objects appended to a thin pack won't be in pack v4 format. Hence
the patch below to deal with that possibility.
An eventual optimization to index-pack when completing a pack would be
to attempt the encoding of appended tree objects into the packv4 format
using the existing dictionary table in the pack, and fall back to the
canonical format if that table doesn't have all the necessary elements.
packv4-parse.c: allow tree entry copying from a canonical tree object
It is possible for a base tree object to be in the canonical
representation. This may happen if the encoder detected an irregularity
preventing a loss free encoding to the pack v4 format, or if a thin pack
was completed with such tree objects.
Signed-off-by: Nicolas Pitre <nico@xxxxxxxxxxx>
diff --git a/packv4-parse.c b/packv4-parse.c
index c62c4ae..36942bb 100644
--- a/packv4-parse.c
+++ b/packv4-parse.c
@@ -10,6 +10,7 @@
#include "cache.h"
#include "packv4-parse.h"
+#include "tree-walk.h"
#include "varint.h"
const unsigned char *get_sha1ref(struct packed_git *p,
@@ -321,6 +322,45 @@ void *pv4_get_commit(struct packed_git *p, struct pack_window **w_curs,
return dst;
}
+static int copy_canonical_tree_entries(struct packed_git *p, off_t offset,
+ unsigned int start, unsigned int count,
+ unsigned char **dstp, unsigned long *sizep)
+{
+ void *data;
+ const void *from, *end;
+ enum object_type type;
+ unsigned long size;
+ struct tree_desc desc;
+
+ data = unpack_entry(p, offset, &type, &size);
+ if (!data)
+ return -1;
+ if (type != OBJ_TREE) {
+ free(data);
+ return -1;
+ }
+
+ init_tree_desc(&desc, data, size);
+
+ while (start--)
+ update_tree_entry(&desc);
+
+ from = desc.buffer;
+ while (count--)
+ update_tree_entry(&desc);
+ end = desc.buffer;
+
+ if (end - from > *sizep) {
+ free(data);
+ return -1;
+ }
+ memcpy(*dstp, from, end - from);
+ *dstp += end - from;
+ *sizep -= end - from;
+ free(data);
+ return 0;
+}
+
static int tree_entry_prefix(unsigned char *buf, unsigned long size,
const unsigned char *path, unsigned mode)
{
@@ -364,7 +404,12 @@ static int decode_entries(struct packed_git *p, struct pack_window **w_curs,
while (*scp & 128)
if (++scp - src >= avail - 20)
return -1;
- /* let's still make sure this is actually a tree */
+ /* is this a canonical tree object? */
+ if ((*scp & 0xf) == OBJ_TREE)
+ 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;
}
--
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