From f55ac4311ad173529cbac7a619d422674a4252ad Mon Sep 17 00:00:00 2001 From: "brian m. carlson" Date: Tue, 15 Jan 2019 00:39:43 +0000 Subject: [PATCH] match-trees: use hashcpy to splice trees When we splice trees together, we operate in place on the tree buffer. If we're using SHA-1 for the hash algorithm, we may not have a full GIT_MAX_RAWSZ (32) bytes to copy. Consequently, it doesn't logically make sense for us to use a struct object_id to represent this type, since it isn't a complete object. Represent this value as a unsigned char pointer instead and copy it when necessary. Signed-off-by: Jeff King Signed-off-by: brian m. carlson Signed-off-by: Junio C Hamano --- match-trees.c | 24 ++++++++++++++++++------ 1 file changed, 18 insertions(+), 6 deletions(-) diff --git a/match-trees.c b/match-trees.c index feca48a5fd..c2b7329e09 100644 --- a/match-trees.c +++ b/match-trees.c @@ -179,7 +179,7 @@ static int splice_tree(const struct object_id *oid1, const char *prefix, char *buf; unsigned long sz; struct tree_desc desc; - struct object_id *rewrite_here; + unsigned char *rewrite_here; const struct object_id *rewrite_with; struct object_id subtree; enum object_type type; @@ -206,9 +206,19 @@ static int splice_tree(const struct object_id *oid1, const char *prefix, if (!S_ISDIR(mode)) die("entry %s in tree %s is not a tree", name, oid_to_hex(oid1)); - rewrite_here = (struct object_id *)(desc.entry.path + - strlen(desc.entry.path) + - 1); + + /* + * We cast here for two reasons: + * + * - to flip the "char *" (for the path) to "unsigned + * char *" (for the hash stored after it) + * + * - to discard the "const"; this is OK because we + * know it points into our non-const "buf" + */ + rewrite_here = (unsigned char *)(desc.entry.path + + strlen(desc.entry.path) + + 1); break; } update_tree_entry(&desc); @@ -217,14 +227,16 @@ static int splice_tree(const struct object_id *oid1, const char *prefix, die("entry %.*s not found in tree %s", toplen, prefix, oid_to_hex(oid1)); if (*subpath) { - status = splice_tree(rewrite_here, subpath, oid2, &subtree); + struct object_id tree_oid; + hashcpy(tree_oid.hash, rewrite_here); + status = splice_tree(&tree_oid, subpath, oid2, &subtree); if (status) return status; rewrite_with = &subtree; } else { rewrite_with = oid2; } - oidcpy(rewrite_here, rewrite_with); + hashcpy(rewrite_here, rewrite_with->hash); status = write_object_file(buf, sz, tree_type, result); free(buf); return status; -- 2.47.1