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Merge branch 'mh/notes-cleanup'

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Code clean-up.

* mh/notes-cleanup:
  load_subtree(): check that `prefix_len` is in the expected range
  load_subtree(): declare some variables to be `size_t`
  hex_to_bytes(): simpler replacement for `get_oid_hex_segment()`
  get_oid_hex_segment(): don't pad the rest of `oid`
  load_subtree(): combine some common code
  get_oid_hex_segment(): return 0 on success
  load_subtree(): only consider blobs to be potential notes
  load_subtree(): check earlier whether an internal node is a tree entry
  load_subtree(): separate logic for internal vs. terminal entries
  load_subtree(): fix incorrect comment
  load_subtree(): reduce the scope of some local variables
  load_subtree(): remove unnecessary conditional
  notes: make GET_NIBBLE macro more robust
This commit is contained in:
Junio C Hamano 2017-09-19 10:47:52 +09:00
commit 30675f7021
1 changed files with 70 additions and 71 deletions
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141
notes.c
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@ -64,7 +64,7 @@ struct non_note {
#define CLR_PTR_TYPE(ptr) ((void *) ((uintptr_t) (ptr) & ~3))
#define SET_PTR_TYPE(ptr, type) ((void *) ((uintptr_t) (ptr) | (type)))
#define GET_NIBBLE(n, sha1) (((sha1[(n) >> 1]) >> ((~(n) & 0x01) << 2)) & 0x0f)
#define GET_NIBBLE(n, sha1) ((((sha1)[(n) >> 1]) >> ((~(n) & 0x01) << 2)) & 0x0f)
#define KEY_INDEX (GIT_SHA1_RAWSZ - 1)
#define FANOUT_PATH_SEPARATORS ((GIT_SHA1_HEXSZ / 2) - 1)
@ -335,31 +335,20 @@ static void note_tree_free(struct int_node *tree)
}
/*
* Convert a partial SHA1 hex string to the corresponding partial SHA1 value.
* - hex - Partial SHA1 segment in ASCII hex format
* - hex_len - Length of above segment. Must be multiple of 2 between 0 and 40
* - sha1 - Partial SHA1 value is written here
* - sha1_len - Max #bytes to store in sha1, Must be >= hex_len / 2, and < 20
* Returns -1 on error (invalid arguments or invalid SHA1 (not in hex format)).
* Otherwise, returns number of bytes written to sha1 (i.e. hex_len / 2).
* Pads sha1 with NULs up to sha1_len (not included in returned length).
* Read `len` pairs of hexadecimal digits from `hex` and write the
* values to `binary` as `len` bytes. Return 0 on success, or -1 if
* the input does not consist of hex digits).
*/
static int get_oid_hex_segment(const char *hex, unsigned int hex_len,
unsigned char *oid, unsigned int oid_len)
static int hex_to_bytes(unsigned char *binary, const char *hex, size_t len)
{
unsigned int i, len = hex_len >> 1;
if (hex_len % 2 != 0 || len > oid_len)
return -1;
for (i = 0; i < len; i++) {
for (; len; len--, hex += 2) {
unsigned int val = (hexval(hex[0]) << 4) | hexval(hex[1]);
if (val & ~0xff)
return -1;
*oid++ = val;
hex += 2;
*binary++ = val;
}
for (; i < oid_len; i++)
*oid++ = 0;
return len;
return 0;
}
static int non_note_cmp(const struct non_note *a, const struct non_note *b)
@ -417,13 +406,10 @@ static void load_subtree(struct notes_tree *t, struct leaf_node *subtree,
struct int_node *node, unsigned int n)
{
struct object_id object_oid;
unsigned int prefix_len;
size_t prefix_len;
void *buf;
struct tree_desc desc;
struct name_entry entry;
int len, path_len;
unsigned char type;
struct leaf_node *l;
buf = fill_tree_descriptor(&desc, &subtree->val_oid);
if (!buf)
@ -431,66 +417,79 @@ static void load_subtree(struct notes_tree *t, struct leaf_node *subtree,
oid_to_hex(&subtree->val_oid));
prefix_len = subtree->key_oid.hash[KEY_INDEX];
assert(prefix_len * 2 >= n);
if (prefix_len >= GIT_SHA1_RAWSZ)
BUG("prefix_len (%"PRIuMAX") is out of range", (uintmax_t)prefix_len);
if (prefix_len * 2 < n)
BUG("prefix_len (%"PRIuMAX") is too small", (uintmax_t)prefix_len);
memcpy(object_oid.hash, subtree->key_oid.hash, prefix_len);
while (tree_entry(&desc, &entry)) {
path_len = strlen(entry.path);
len = get_oid_hex_segment(entry.path, path_len,
object_oid.hash + prefix_len, GIT_SHA1_RAWSZ - prefix_len);
if (len < 0)
goto handle_non_note; /* entry.path is not a SHA1 */
len += prefix_len;
unsigned char type;
struct leaf_node *l;
size_t path_len = strlen(entry.path);
if (path_len == 2 * (GIT_SHA1_RAWSZ - prefix_len)) {
/* This is potentially the remainder of the SHA-1 */
if (!S_ISREG(entry.mode))
/* notes must be blobs */
goto handle_non_note;
if (hex_to_bytes(object_oid.hash + prefix_len, entry.path,
GIT_SHA1_RAWSZ - prefix_len))
goto handle_non_note; /* entry.path is not a SHA1 */
/*
* If object SHA1 is complete (len == 20), assume note object
* If object SHA1 is incomplete (len < 20), and current
* component consists of 2 hex chars, assume note subtree
*/
if (len <= GIT_SHA1_RAWSZ) {
type = PTR_TYPE_NOTE;
l = (struct leaf_node *)
xcalloc(1, sizeof(struct leaf_node));
oidcpy(&l->key_oid, &object_oid);
oidcpy(&l->val_oid, entry.oid);
if (len < GIT_SHA1_RAWSZ) {
if (!S_ISDIR(entry.mode) || path_len != 2)
goto handle_non_note; /* not subtree */
l->key_oid.hash[KEY_INDEX] = (unsigned char) len;
type = PTR_TYPE_SUBTREE;
}
if (note_tree_insert(t, node, n, l, type,
combine_notes_concatenate))
die("Failed to load %s %s into notes tree "
"from %s",
type == PTR_TYPE_NOTE ? "note" : "subtree",
oid_to_hex(&l->key_oid), t->ref);
} else if (path_len == 2) {
/* This is potentially an internal node */
size_t len = prefix_len;
if (!S_ISDIR(entry.mode))
/* internal nodes must be trees */
goto handle_non_note;
if (hex_to_bytes(object_oid.hash + len++, entry.path, 1))
goto handle_non_note; /* entry.path is not a SHA1 */
/*
* Pad the rest of the SHA-1 with zeros,
* except for the last byte, where we write
* the length:
*/
memset(object_oid.hash + len, 0, GIT_SHA1_RAWSZ - len - 1);
object_oid.hash[KEY_INDEX] = (unsigned char)len;
type = PTR_TYPE_SUBTREE;
} else {
/* This can't be part of a note */
goto handle_non_note;
}
l = xcalloc(1, sizeof(*l));
oidcpy(&l->key_oid, &object_oid);
oidcpy(&l->val_oid, entry.oid);
if (note_tree_insert(t, node, n, l, type,
combine_notes_concatenate))
die("Failed to load %s %s into notes tree "
"from %s",
type == PTR_TYPE_NOTE ? "note" : "subtree",
oid_to_hex(&l->key_oid), t->ref);
continue;
handle_non_note:
/*
* Determine full path for this non-note entry:
* The filename is already found in entry.path, but the
* directory part of the path must be deduced from the subtree
* containing this entry. We assume here that the overall notes
* tree follows a strict byte-based progressive fanout
* structure (i.e. using 2/38, 2/2/36, etc. fanouts, and not
* e.g. 4/36 fanout). This means that if a non-note is found at
* path "dead/beef", the following code will register it as
* being found on "de/ad/beef".
* On the other hand, if you use such non-obvious non-note
* paths in the middle of a notes tree, you deserve what's
* coming to you ;). Note that for non-notes that are not
* SHA1-like at the top level, there will be no problems.
*
* To conclude, it is strongly advised to make sure non-notes
* have at least one non-hex character in the top-level path
* component.
* Determine full path for this non-note entry. The
* filename is already found in entry.path, but the
* directory part of the path must be deduced from the
* subtree containing this entry based on our
* knowledge that the overall notes tree follows a
* strict byte-based progressive fanout structure
* (i.e. using 2/38, 2/2/36, etc. fanouts).
*/
{
struct strbuf non_note_path = STRBUF_INIT;
const char *q = oid_to_hex(&subtree->key_oid);
int i;
size_t i;
for (i = 0; i < prefix_len; i++) {
strbuf_addch(&non_note_path, *q++);
strbuf_addch(&non_note_path, *q++);