get_short_sha1: refactor init of disambiguation code
The disambiguation machinery has two callers: get_short_sha1 and for_each_abbrev. Both need to repeat much of the same setup: declaring buffers, sanity-checking lengths, preparing the prefixes, etc. Let's pull that into a single init function so we can avoid repeating ourselves. Pulling the buffers into the "struct disambiguate_state" isn't strictly necessary, but it does make things simpler for the callers, who no longer have to worry about sizing them correctly (i.e., it's an implicit requirement that the caller provide 20- and 40-byte buffers). And while we're touching this code, we can convert any magic-number sizes to the more modern GIT_SHA1_* constants. Signed-off-by: Jeff King <peff@peff.net> Signed-off-by: Junio C Hamano <gitster@pobox.com>
Jeff King committed
Sep 26, 2016 at 08:00 UTC
0016043bf46f4b85054c61f9000ccc58d0ef4ad7
1 file changed
+35
-44
sha1_name.c
+35
-44
@@ -13,9 +13,13 @@ static int get_sha1_oneline(const char *, unsigned char *, struct commit_list *)
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typedef int (*disambiguate_hint_fn)(const unsigned char *, void *);
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struct disambiguate_state {
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+ int len; /* length of prefix in hex chars */
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+ char hex_pfx[GIT_SHA1_HEXSZ];
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+ unsigned char bin_pfx[GIT_SHA1_RAWSZ];
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+
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disambiguate_hint_fn fn;
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void *cb_data;
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- unsigned char candidate[20];
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+ unsigned char candidate[GIT_SHA1_RAWSZ];
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unsigned candidate_exists:1;
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unsigned candidate_checked:1;
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unsigned candidate_ok:1;
@@ -72,10 +76,10 @@ static void update_candidates(struct disambiguate_state *ds, const unsigned char
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/* otherwise, current can be discarded and candidate is still good */
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}
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-static void find_short_object_filename(int len, const char *hex_pfx, struct disambiguate_state *ds)
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+static void find_short_object_filename(struct disambiguate_state *ds)
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{
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struct alternate_object_database *alt;
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- char hex[40];
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+ char hex[GIT_SHA1_HEXSZ];
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static struct alternate_object_database *fakeent;
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if (!fakeent) {
@@ -95,7 +99,7 @@ static void find_short_object_filename(int len, const char *hex_pfx, struct disa
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}
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fakeent->next = alt_odb_list;
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- xsnprintf(hex, sizeof(hex), "%.2s", hex_pfx);
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+ xsnprintf(hex, sizeof(hex), "%.2s", ds->hex_pfx);
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for (alt = fakeent; alt && !ds->ambiguous; alt = alt->next) {
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struct dirent *de;
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DIR *dir;
@@ -103,7 +107,7 @@ static void find_short_object_filename(int len, const char *hex_pfx, struct disa
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* every alt_odb struct has 42 extra bytes after the base
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* for exactly this purpose
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*/
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- xsnprintf(alt->name, 42, "%.2s/", hex_pfx);
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+ xsnprintf(alt->name, 42, "%.2s/", ds->hex_pfx);
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dir = opendir(alt->base);
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if (!dir)
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continue;
@@ -113,7 +117,7 @@ static void find_short_object_filename(int len, const char *hex_pfx, struct disa
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if (strlen(de->d_name) != 38)
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continue;
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- if (memcmp(de->d_name, hex_pfx + 2, len - 2))
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+ if (memcmp(de->d_name, ds->hex_pfx + 2, ds->len - 2))
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continue;
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memcpy(hex + 2, de->d_name, 38);
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if (!get_sha1_hex(hex, sha1))
@@ -138,9 +142,7 @@ static int match_sha(unsigned len, const unsigned char *a, const unsigned char *
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return 1;
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}
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-static void unique_in_pack(int len,
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- const unsigned char *bin_pfx,
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- struct packed_git *p,
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+static void unique_in_pack(struct packed_git *p,
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struct disambiguate_state *ds)
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{
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uint32_t num, last, i, first = 0;
@@ -155,7 +157,7 @@ static void unique_in_pack(int len,
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int cmp;
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current = nth_packed_object_sha1(p, mid);
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- cmp = hashcmp(bin_pfx, current);
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+ cmp = hashcmp(ds->bin_pfx, current);
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if (!cmp) {
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first = mid;
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break;
@@ -174,20 +176,19 @@ static void unique_in_pack(int len,
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*/
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for (i = first; i < num && !ds->ambiguous; i++) {
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current = nth_packed_object_sha1(p, i);
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- if (!match_sha(len, bin_pfx, current))
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+ if (!match_sha(ds->len, ds->bin_pfx, current))
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break;
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update_candidates(ds, current);
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}
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}
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-static void find_short_packed_object(int len, const unsigned char *bin_pfx,
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- struct disambiguate_state *ds)
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+static void find_short_packed_object(struct disambiguate_state *ds)
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{
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struct packed_git *p;
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prepare_packed_git();
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for (p = packed_git; p && !ds->ambiguous; p = p->next)
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- unique_in_pack(len, bin_pfx, p, ds);
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+ unique_in_pack(p, ds);
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}
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#define SHORT_NAME_NOT_FOUND (-1)
@@ -281,14 +282,17 @@ static int disambiguate_blob_only(const unsigned char *sha1, void *cb_data_unuse
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return kind == OBJ_BLOB;
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}
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-static int prepare_prefixes(const char *name, int len,
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- unsigned char *bin_pfx,
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- char *hex_pfx)
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+static int init_object_disambiguation(const char *name, int len,
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+ struct disambiguate_state *ds)
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{
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int i;
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- hashclr(bin_pfx);
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- memset(hex_pfx, 'x', 40);
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+ if (len < MINIMUM_ABBREV || len > GIT_SHA1_HEXSZ)
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+ return -1;
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+
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+ memset(ds, 0, sizeof(*ds));
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+ memset(ds->hex_pfx, 'x', GIT_SHA1_HEXSZ);
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+
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for (i = 0; i < len ;i++) {
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unsigned char c = name[i];
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unsigned char val;
@@ -302,11 +306,14 @@ static int prepare_prefixes(const char *name, int len,
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}
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else
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return -1;
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- hex_pfx[i] = c;
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+ ds->hex_pfx[i] = c;
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if (!(i & 1))
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val <<= 4;
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- bin_pfx[i >> 1] |= val;
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+ ds->bin_pfx[i >> 1] |= val;
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}
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+
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+ ds->len = len;
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+ prepare_alt_odb();
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return 0;
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}
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@@ -314,20 +321,12 @@ static int get_short_sha1(const char *name, int len, unsigned char *sha1,
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unsigned flags)
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{
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int status;
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- char hex_pfx[40];
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- unsigned char bin_pfx[20];
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struct disambiguate_state ds;
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int quietly = !!(flags & GET_SHA1_QUIETLY);
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- if (len < MINIMUM_ABBREV || len > 40)
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- return -1;
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- if (prepare_prefixes(name, len, bin_pfx, hex_pfx) < 0)
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+ if (init_object_disambiguation(name, len, &ds) < 0)
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return -1;
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- prepare_alt_odb();
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-
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- memset(&ds, 0, sizeof(ds));
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-
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if (HAS_MULTI_BITS(flags & GET_SHA1_DISAMBIGUATORS))
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die("BUG: multiple get_short_sha1 disambiguator flags");
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@@ -342,36 +341,28 @@ static int get_short_sha1(const char *name, int len, unsigned char *sha1,
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else if (flags & GET_SHA1_BLOB)
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ds.fn = disambiguate_blob_only;
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- find_short_object_filename(len, hex_pfx, &ds);
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- find_short_packed_object(len, bin_pfx, &ds);
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+ find_short_object_filename(&ds);
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+ find_short_packed_object(&ds);
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status = finish_object_disambiguation(&ds, sha1);
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if (!quietly && (status == SHORT_NAME_AMBIGUOUS))
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- return error("short SHA1 %.*s is ambiguous.", len, hex_pfx);
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+ return error("short SHA1 %.*s is ambiguous.", ds.len, ds.hex_pfx);
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return status;
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}
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int for_each_abbrev(const char *prefix, each_abbrev_fn fn, void *cb_data)
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{
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- char hex_pfx[40];
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- unsigned char bin_pfx[20];
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struct disambiguate_state ds;
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- int len = strlen(prefix);
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- if (len < MINIMUM_ABBREV || len > 40)
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+ if (init_object_disambiguation(prefix, strlen(prefix), &ds) < 0)
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return -1;
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- if (prepare_prefixes(prefix, len, bin_pfx, hex_pfx) < 0)
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- return -1;
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-
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- prepare_alt_odb();
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- memset(&ds, 0, sizeof(ds));
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ds.always_call_fn = 1;
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ds.cb_data = cb_data;
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ds.fn = fn;
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- find_short_object_filename(len, hex_pfx, &ds);
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- find_short_packed_object(len, bin_pfx, &ds);
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+ find_short_object_filename(&ds);
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+ find_short_packed_object(&ds);
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return ds.ambiguous;
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}
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