convert trivial cases to FLEX_ARRAY macros

Using FLEX_ARRAY macros reduces the amount of manual
computation size we have to do. It also ensures we don't
overflow size_t, and it makes sure we write the same number
of bytes that we allocated.

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

4 files changed, 11 insertions, 18 deletions

diff --git a/builtin/blame.c b/builtin/blame.c
index 4de9e10148..e175d86e56 100644
--- a/builtin/blame.c
+++ b/builtin/blame.c
@@ -459,13 +459,11 @@ static void queue_blames(struct scoreboard *sb, struct origin *porigin,
 static struct origin *make_origin(struct commit *commit, const char *path)
 {
 	struct origin *o;
-	size_t pathlen = strlen(path) + 1;
-	o = xcalloc(1, sizeof(*o) + pathlen);
+	FLEX_ALLOC_STR(o, path, path);
 	o->commit = commit;
 	o->refcnt = 1;
 	o->next = commit->util;
 	commit->util = o;
-	memcpy(o->path, path, pathlen); /* includes NUL */
 	return o;
 }
 
diff --git a/builtin/help.c b/builtin/help.c
index 1cd0c1ee44..3c55ce4563 100644
--- a/builtin/help.c
+++ b/builtin/help.c
@@ -171,12 +171,10 @@ static void exec_man_cmd(const char *cmd, const char *page)
 static void add_man_viewer(const char *name)
 {
 	struct man_viewer_list **p = &man_viewer_list;
-	size_t len = strlen(name);
 
 	while (*p)
 		p = &((*p)->next);
-	*p = xcalloc(1, (sizeof(**p) + len + 1));
-	memcpy((*p)->name, name, len); /* NUL-terminated by xcalloc */
+	FLEX_ALLOC_STR(*p, name, name);
 }
 
 static int supported_man_viewer(const char *name, size_t len)
@@ -190,9 +188,8 @@ static void do_add_man_viewer_info(const char *name,
 				   size_t len,
 				   const char *value)
 {
-	struct man_viewer_info_list *new = xcalloc(1, sizeof(*new) + len + 1);
-
-	memcpy(new->name, name, len); /* NUL-terminated by xcalloc */
+	struct man_viewer_info_list *new;
+	FLEX_ALLOC_MEM(new, name, name, len);
 	new->info = xstrdup(value);
 	new->next = man_viewer_info_list;
 	man_viewer_info_list = new;
diff --git a/builtin/mktree.c b/builtin/mktree.c
index a964d6be52..b0aab65353 100644
--- a/builtin/mktree.c
+++ b/builtin/mktree.c
@@ -19,16 +19,17 @@ static int alloc, used;
 static void append_to_tree(unsigned mode, unsigned char *sha1, char *path)
 {
 	struct treeent *ent;
-	int len = strlen(path);
+	size_t len = strlen(path);
 	if (strchr(path, '/'))
 		die("path %s contains slash", path);
 
-	ALLOC_GROW(entries, used + 1, alloc);
-	ent = entries[used++] = xmalloc(sizeof(**entries) + len + 1);
+	FLEX_ALLOC_MEM(ent, name, path, len);
 	ent->mode = mode;
 	ent->len = len;
 	hashcpy(ent->sha1, sha1);
-	memcpy(ent->name, path, len+1);
+
+	ALLOC_GROW(entries, used + 1, alloc);
+	entries[used++] = ent;
 }
 
 static int ent_compare(const void *a_, const void *b_)
diff --git a/builtin/reflog.c b/builtin/reflog.c
index 9980731ee7..2d46b6482a 100644
--- a/builtin/reflog.c
+++ b/builtin/reflog.c
@@ -382,11 +382,9 @@ static int collect_reflog(const char *ref, const struct object_id *oid, int unus
 {
 	struct collected_reflog *e;
 	struct collect_reflog_cb *cb = cb_data;
-	size_t namelen = strlen(ref);
 
-	e = xmalloc(sizeof(*e) + namelen + 1);
+	FLEX_ALLOC_STR(e, reflog, ref);
 	hashcpy(e->sha1, oid->hash);
-	memcpy(e->reflog, ref, namelen + 1);
 	ALLOC_GROW(cb->e, cb->nr + 1, cb->alloc);
 	cb->e[cb->nr++] = e;
 	return 0;
@@ -411,8 +409,7 @@ static struct reflog_expire_cfg *find_cfg_ent(const char *pattern, size_t len)
 		    ent->pattern[len] == '\0')
 			return ent;
 
-	ent = xcalloc(1, sizeof(*ent) + len + 1);
-	memcpy(ent->pattern, pattern, len);
+	FLEX_ALLOC_MEM(ent, pattern, pattern, len);
 	*reflog_expire_cfg_tail = ent;
 	reflog_expire_cfg_tail = &(ent->next);
 	return ent;