fast-export: tighten anonymize_mem() interface to handle only strings

While the anonymize_mem() interface _can_ store arbitrary byte
sequences, none of the callers uses this feature (as of the previous
commit). We'd like to keep it that way, as we'll be exposing the
string-like nature of the anonymization routines to the user. So let's
tighten up the interface a bit:

  - don't treat "len" as an out-parameter from anonymize_mem(); this
    ensures callers treat the pointer result as a NUL-terminated string

  - likewise, don't treat "len" as an out-parameter from generator
    functions

  - swap out "void *" for "char *" as appropriate to signal that we
    don't handle arbitrary memory

  - rename the function to anonymize_str()

This will also open up some optimization opportunities in a future
patch.

Note that we can't drop the "len" parameter entirely. Some callers do
pass in partial strings (e.g., "foo/bar", len=3) to avoid copying, and
we need to handle those still.

Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

diff --git a/builtin/fast-export.c b/builtin/fast-export.c
index 4a3a4c933ea68456b4654462563ed033958ae00e..d8ea067630f94600dd86a83f649aef652d33c07a 100644 (file)
--- a/builtin/fast-export.c
+++ b/builtin/fast-export.c
@@ -145,31 +145,30 @@ static int anonymized_entry_cmp(const void *unused_cmp_data,
  * the same anonymized string with another. The actual generation
  * is farmed out to the generate function.
  */
-static const void *anonymize_mem(struct hashmap *map,
-                                void *(*generate)(const void *, size_t *),
-                                const void *orig, size_t *len)
+static const char *anonymize_str(struct hashmap *map,
+                                char *(*generate)(const char *, size_t),
+                                const char *orig, size_t len)
 {
        struct anonymized_entry key, *ret;
 
        if (!map->cmpfn)
                hashmap_init(map, anonymized_entry_cmp, NULL, 0);
 
-       hashmap_entry_init(&key.hash, memhash(orig, *len));
+       hashmap_entry_init(&key.hash, memhash(orig, len));
        key.orig = orig;
-       key.orig_len = *len;
+       key.orig_len = len;
        ret = hashmap_get_entry(map, &key, hash, NULL);
 
        if (!ret) {
                ret = xmalloc(sizeof(*ret));
                hashmap_entry_init(&ret->hash, key.hash.hash);
-               ret->orig = xmemdupz(orig, *len);
-               ret->orig_len = *len;
+               ret->orig = xmemdupz(orig, len);
+               ret->orig_len = len;
                ret->anon = generate(orig, len);
-               ret->anon_len = *len;
+               ret->anon_len = strlen(ret->anon);
                hashmap_put(map, &ret->hash);
        }
 
-       *len = ret->anon_len;
        return ret->anon;
 }
 
@@ -181,13 +180,13 @@ static const void *anonymize_mem(struct hashmap *map,
  */
 static void anonymize_path(struct strbuf *out, const char *path,
                           struct hashmap *map,
-                          void *(*generate)(const void *, size_t *))
+                          char *(*generate)(const char *, size_t))
 {
        while (*path) {
                const char *end_of_component = strchrnul(path, '/');
                size_t len = end_of_component - path;
-               const char *c = anonymize_mem(map, generate, path, &len);
-               strbuf_add(out, c, len);
+               const char *c = anonymize_str(map, generate, path, len);
+               strbuf_addstr(out, c);
                path = end_of_component;
                if (*path)
                        strbuf_addch(out, *path++);
@@ -361,12 +360,12 @@ static void print_path_1(const char *path)
                printf("%s", path);
 }
 
-static void *anonymize_path_component(const void *path, size_t *len)
+static char *anonymize_path_component(const char *path, size_t len)
 {
        static int counter;
        struct strbuf out = STRBUF_INIT;
        strbuf_addf(&out, "path%d", counter++);
-       return strbuf_detach(&out, len);
+       return strbuf_detach(&out, NULL);
 }
 
 static void print_path(const char *path)
@@ -383,7 +382,7 @@ static void print_path(const char *path)
        }
 }
 
-static void *generate_fake_oid(const void *old, size_t *len)
+static char *generate_fake_oid(const char *old, size_t len)
 {
        static uint32_t counter = 1; /* avoid null oid */
        const unsigned hashsz = the_hash_algo->rawsz;
@@ -399,7 +398,7 @@ static const char *anonymize_oid(const char *oid_hex)
 {
        static struct hashmap objs;
        size_t len = strlen(oid_hex);
-       return anonymize_mem(&objs, generate_fake_oid, oid_hex, &len);
+       return anonymize_str(&objs, generate_fake_oid, oid_hex, len);
 }
 
 static void show_filemodify(struct diff_queue_struct *q,
@@ -496,12 +495,12 @@ static const char *find_encoding(const char *begin, const char *end)
        return bol;
 }
 
-static void *anonymize_ref_component(const void *old, size_t *len)
+static char *anonymize_ref_component(const char *old, size_t len)
 {
        static int counter;
        struct strbuf out = STRBUF_INIT;
        strbuf_addf(&out, "ref%d", counter++);
-       return strbuf_detach(&out, len);
+       return strbuf_detach(&out, NULL);
 }
 
 static const char *anonymize_refname(const char *refname)
@@ -550,13 +549,13 @@ static char *anonymize_commit_message(const char *old)
 }
 
 static struct hashmap idents;
-static void *anonymize_ident(const void *old, size_t *len)
+static char *anonymize_ident(const char *old, size_t len)
 {
        static int counter;
        struct strbuf out = STRBUF_INIT;
        strbuf_addf(&out, "User %d <user%d@example.com>", counter, counter);
        counter++;
-       return strbuf_detach(&out, len);
+       return strbuf_detach(&out, NULL);
 }
 
 /*
@@ -591,9 +590,9 @@ static void anonymize_ident_line(const char **beg, const char **end)
                size_t len;
 
                len = split.mail_end - split.name_begin;
-               ident = anonymize_mem(&idents, anonymize_ident,
-                                     split.name_begin, &len);
-               strbuf_add(out, ident, len);
+               ident = anonymize_str(&idents, anonymize_ident,
+                                     split.name_begin, len);
+               strbuf_addstr(out, ident);
                strbuf_addch(out, ' ');
                strbuf_add(out, split.date_begin, split.tz_end - split.date_begin);
        } else {
@@ -733,12 +732,12 @@ static void handle_commit(struct commit *commit, struct rev_info *rev,
        show_progress();
 }
 
-static void *anonymize_tag(const void *old, size_t *len)
+static char *anonymize_tag(const char *old, size_t len)
 {
        static int counter;
        struct strbuf out = STRBUF_INIT;
        strbuf_addf(&out, "tag message %d", counter++);
-       return strbuf_detach(&out, len);
+       return strbuf_detach(&out, NULL);
 }
 
 static void handle_tail(struct object_array *commits, struct rev_info *revs,
@@ -808,8 +807,8 @@ static void handle_tag(const char *name, struct tag *tag)
                name = anonymize_refname(name);
                if (message) {
                        static struct hashmap tags;
-                       message = anonymize_mem(&tags, anonymize_tag,
-                                               message, &message_size);
+                       message = anonymize_str(&tags, anonymize_tag,
+                                               message, message_size);
                }
        }