[PATCH 3/6] fast-export: factor out anonymized_entry creation

[Jeff King <peff@peff.net>]

When anonymizing output, there's only one spot where we generate new
entries to add to our hashmap: when anonymize_str() doesn't find an
entry, we use the generate() callback to make one and add it. Let's pull
that into its own function in preparation for another caller.

Note that we'll add one extra feature. In anonymize_str(), we know that
we won't find an existing entry in the hashmap (since it will only try
to add after failing to find one). But other callers won't have the same
behavior, so we should catch this case and free the now-dangling entry.

Signed-off-by: Jeff King <peff@peff.net>
---
 builtin/fast-export.c | 35 ++++++++++++++++++++++++++---------
 1 file changed, 26 insertions(+), 9 deletions(-)

diff --git a/builtin/fast-export.c b/builtin/fast-export.c
index ba9ab3a97e5..5a0b63219ad 100644
--- a/builtin/fast-export.c
+++ b/builtin/fast-export.c
@@ -139,6 +139,29 @@ static int anonymized_entry_cmp(const void *cmp_data UNUSED,
 	return strcmp(a->orig, b->orig);
 }
 
+static struct anonymized_entry *add_anonymized_entry(struct hashmap *map,
+						     unsigned hash,
+						     const char *orig, size_t len,
+						     char *anon)
+{
+	struct anonymized_entry *ret, *old;
+
+	if (!map->cmpfn)
+		hashmap_init(map, anonymized_entry_cmp, NULL, 0);
+
+	FLEX_ALLOC_MEM(ret, orig, orig, len);
+	hashmap_entry_init(&ret->hash, hash);
+	ret->anon = anon;
+	old = hashmap_put_entry(map, ret, hash);
+
+	if (old) {
+		free(old->anon);
+		free(old);
+	}
+
+	return ret;
+}
+
 /*
  * Basically keep a cache of X->Y so that we can repeatedly replace
  * the same anonymized string with another. The actual generation
@@ -164,15 +187,9 @@ static const char *anonymize_str(struct hashmap *map,
 		ret = hashmap_get_entry(map, &key, hash, &key);
 
 	/* ...and finally generate a new mapping if necessary */
-	if (!ret) {
-		if (!map->cmpfn)
-			hashmap_init(map, anonymized_entry_cmp, NULL, 0);
-
-		FLEX_ALLOC_MEM(ret, orig, orig, len);
-		hashmap_entry_init(&ret->hash, key.hash.hash);
-		ret->anon = generate(data);
-		hashmap_put(map, &ret->hash);
-	}
+	if (!ret)
+		ret = add_anonymized_entry(map, key.hash.hash,
+					   orig, len, generate(data));
 
 	return ret->anon;
 }
-- 
2.40.0.595.g9b96b494d8c