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[PATCH v2 1/3] refs: expose 'for_each_fullref_in_prefixes'

From
Taylor Blau <me@ttaylorr.com>
Date
Jan 20, 2021, 16:04 UTC
Message-ID
<bda314fe7ae1629ba068a0c4ada9b6adc20576eb.1611158549.git.me@ttaylorr.com>
In-Reply-To
<cover.1611158549.git.me@ttaylorr.com>

This function was used in the ref-filter.c code to find the longest common prefix of among a set of refspecs, and then to iterate all of the references that descend from that prefix.

A future patch will want to use that same code from ls-refs.c, so prepare by exposing and moving it to refs.c. Since there is nothing specific to the ref-filter code here (other than that it was previously the only caller of this function), this really belongs in the more generic refs.h header.

The code moved in this patch is identical before and after, with the one exception of renaming some arguments to be consistent with other functions exposed in refs.h.

Signed-off-by: Taylor Blau <me@ttaylorr.com>
---
 ref-filter.c | 74 ++------------------------------------------
 refs.c       | 87 ++++++++++++++++++++++++++++++++++++++++++++++++++++
 refs.h       |  9 ++++++
 3 files changed, 98 insertions(+), 72 deletions(-)
diff --git a/ref-filter.c b/ref-filter.c
index aa260bfd09..f918f00151 100644
--- a/ref-filter.c
+++ b/ref-filter.c
@@ -1929,64 +1929,6 @@ static int filter_pattern_match(struct ref_filter *filter, const char *refname)
 	return match_pattern(filter, refname);
 }
 
-static int qsort_strcmp(const void *va, const void *vb)
-{
-	const char *a = *(const char **)va;
-	const char *b = *(const char **)vb;
-
-	return strcmp(a, b);
-}
-
-static void find_longest_prefixes_1(struct string_list *out,
-				  struct strbuf *prefix,
-				  const char **patterns, size_t nr)
-{
-	size_t i;
-
-	for (i = 0; i < nr; i++) {
-		char c = patterns[i][prefix->len];
-		if (!c || is_glob_special(c)) {
-			string_list_append(out, prefix->buf);
-			return;
-		}
-	}
-
-	i = 0;
-	while (i < nr) {
-		size_t end;
-
-		/*
-		* Set "end" to the index of the element _after_ the last one
-		* in our group.
-		*/
-		for (end = i + 1; end < nr; end++) {
-			if (patterns[i][prefix->len] != patterns[end][prefix->len])
-				break;
-		}
-
-		strbuf_addch(prefix, patterns[i][prefix->len]);
-		find_longest_prefixes_1(out, prefix, patterns + i, end - i);
-		strbuf_setlen(prefix, prefix->len - 1);
-
-		i = end;
-	}
-}
-
-static void find_longest_prefixes(struct string_list *out,
-				  const char **patterns)
-{
-	struct strvec sorted = STRVEC_INIT;
-	struct strbuf prefix = STRBUF_INIT;
-
-	strvec_pushv(&sorted, patterns);
-	QSORT(sorted.v, sorted.nr, qsort_strcmp);
-
-	find_longest_prefixes_1(out, &prefix, sorted.v, sorted.nr);
-
-	strvec_clear(&sorted);
-	strbuf_release(&prefix);
-}
-
 /*
  * This is the same as for_each_fullref_in(), but it tries to iterate
  * only over the patterns we'll care about. Note that it _doesn't_ do a full
@@ -1997,10 +1939,6 @@ static int for_each_fullref_in_pattern(struct ref_filter *filter,
 				       void *cb_data,
 				       int broken)
 {
-	struct string_list prefixes = STRING_LIST_INIT_DUP;
-	struct string_list_item *prefix;
-	int ret;
-
 	if (!filter->match_as_path) {
 		/*
 		 * in this case, the patterns are applied after
@@ -2024,16 +1962,8 @@ static int for_each_fullref_in_pattern(struct ref_filter *filter,
 		return for_each_fullref_in("", cb, cb_data, broken);
 	}
 
-	find_longest_prefixes(&prefixes, filter->name_patterns);
-
-	for_each_string_list_item(prefix, &prefixes) {
-		ret = for_each_fullref_in(prefix->string, cb, cb_data, broken);
-		if (ret)
-			break;
-	}
-
-	string_list_clear(&prefixes, 0);
-	return ret;
+	return for_each_fullref_in_prefixes(NULL, filter->name_patterns,
+					    cb, cb_data, broken);
 }
 
 /*
diff --git a/refs.c b/refs.c
index 13dc2c3291..0b5a68588f 100644
--- a/refs.c
+++ b/refs.c
@@ -1546,6 +1546,93 @@ int for_each_rawref(each_ref_fn fn, void *cb_data)
 	return refs_for_each_rawref(get_main_ref_store(the_repository), fn, cb_data);
 }
 
+static int qsort_strcmp(const void *va, const void *vb)
+{
+	const char *a = *(const char **)va;
+	const char *b = *(const char **)vb;
+
+	return strcmp(a, b);
+}
+
+static void find_longest_prefixes_1(struct string_list *out,
+				  struct strbuf *prefix,
+				  const char **patterns, size_t nr)
+{
+	size_t i;
+
+	for (i = 0; i < nr; i++) {
+		char c = patterns[i][prefix->len];
+		if (!c || is_glob_special(c)) {
+			string_list_append(out, prefix->buf);
+			return;
+		}
+	}
+
+	i = 0;
+	while (i < nr) {
+		size_t end;
+
+		/*
+		* Set "end" to the index of the element _after_ the last one
+		* in our group.
+		*/
+		for (end = i + 1; end < nr; end++) {
+			if (patterns[i][prefix->len] != patterns[end][prefix->len])
+				break;
+		}
+
+		strbuf_addch(prefix, patterns[i][prefix->len]);
+		find_longest_prefixes_1(out, prefix, patterns + i, end - i);
+		strbuf_setlen(prefix, prefix->len - 1);
+
+		i = end;
+	}
+}
+
+static void find_longest_prefixes(struct string_list *out,
+				  const char **patterns)
+{
+	struct strvec sorted = STRVEC_INIT;
+	struct strbuf prefix = STRBUF_INIT;
+
+	strvec_pushv(&sorted, patterns);
+	QSORT(sorted.v, sorted.nr, qsort_strcmp);
+
+	find_longest_prefixes_1(out, &prefix, sorted.v, sorted.nr);
+
+	strvec_clear(&sorted);
+	strbuf_release(&prefix);
+}
+
+int for_each_fullref_in_prefixes(const char *namespace,
+				 const char **patterns,
+				 each_ref_fn fn, void *cb_data,
+				 unsigned int broken)
+{
+	struct string_list prefixes = STRING_LIST_INIT_DUP;
+	struct string_list_item *prefix;
+	struct strbuf buf = STRBUF_INIT;
+	int ret = 0, namespace_len;
+
+	find_longest_prefixes(&prefixes, patterns);
+
+	if (namespace)
+		strbuf_addstr(&buf, namespace);
+	namespace_len = buf.len;
+
+	for_each_string_list_item(prefix, &prefixes) {
+		strbuf_addf(&buf, "%s", prefix->string);
+		ret = for_each_fullref_in(buf.buf, fn, cb_data, broken);
+		if (ret)
+			break;
+		strbuf_setlen(&buf, namespace_len);
+	}
+
+	string_list_clear(&prefixes, 0);
+	strbuf_release(&buf);
+	return ret;
+}
+
 static int refs_read_special_head(struct ref_store *ref_store,
 				  const char *refname, struct object_id *oid,
 				  struct strbuf *referent, unsigned int *type)
diff --git a/refs.h b/refs.h
index ff05d2e9fe..c5fd35487d 100644
--- a/refs.h
+++ b/refs.h
@@ -347,6 +347,15 @@ int refs_for_each_fullref_in(struct ref_store *refs, const char *prefix,
 int for_each_fullref_in(const char *prefix, each_ref_fn fn, void *cb_data,
 			unsigned int broken);
 
+/**
+ * iterate all refs in "patterns" by partitioning patterns into disjoint sets
+ * and iterating the longest-common prefix of each set.
+ *
+ * callers should be prepared to ignore references that they did not ask for.
+ */
+int for_each_fullref_in_prefixes(const char *namespace, const char **patterns,
+				 each_ref_fn fn, void *cb_data,
+				 unsigned int broken);
 /**
  * iterate refs from the respective area.
  */
-- 
2.30.0.138.g6d7191ea01
Previous: Taylor BlauNext: Jeff King
Message 15 of 27 in “Re: [PATCH 1/1] ls-refs.c: minimize number of refs visited”
  1. Jacob VosmaerJan 19, 2021
  2. 0/2 ls-refs: only traverse through longest common ref prefixTaylor Blau, Jan 19, 2021
  3. 2/2 ls-refs.c: traverse longest common ref prefixTaylor Blau, Jan 19, 2021
  4. Jeff KingJan 19, 2021
  5. Taylor BlauJan 19, 2021
  6. Jeff KingJan 20, 2021
  7. Jacob VosmaerJan 20, 2021
  8. 1/2 refs: expose 'for_each_fullref_in_prefixes'Taylor Blau, Jan 19, 2021
  9. 0/3 ls-refs: traverse prefixes of disjoint "ref-prefix" setsTaylor Blau, Jan 20, 2021
  10. 2/3 ls-refs.c: initialize 'prefixes' before using itTaylor Blau, Jan 20, 2021
  11. Jeff KingJan 20, 2021
  12. Taylor BlauJan 20, 2021
  13. Jacob VosmaerJan 20, 2021
  14. 3/3 ls-refs.c: traverse prefixes of disjoint "ref-prefix" setsTaylor Blau, Jan 20, 2021
  15. 1/3 refs: expose 'for_each_fullref_in_prefixes'Taylor Blau, Jan 20, 2021
  16. Jeff KingJan 20, 2021
  17. Taylor BlauJan 20, 2021
  18. Junio C HamanoJan 23, 2021
  19. Taylor BlauJan 25, 2021
  20. Junio C HamanoJan 23, 2021
  21. Taylor BlauJan 19, 2021
  22. Jeff KingJan 19, 2021
  23. Jeff KingJan 19, 2021
  24. Taylor BlauJan 19, 2021
  25. Jeff KingJan 19, 2021
  26. Jeff KingJan 19, 2021
  27. Taylor BlauJan 19, 2021

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