Merge branch 'jk/tighten-alloc' into maint

* jk/tighten-alloc: (23 commits)
  compat/mingw: brown paper bag fix for 50a6c8e
  ewah: convert to REALLOC_ARRAY, etc
  convert ewah/bitmap code to use xmalloc
  diff_populate_gitlink: use a strbuf
  transport_anonymize_url: use xstrfmt
  git-compat-util: drop mempcpy compat code
  sequencer: simplify memory allocation of get_message
  test-path-utils: fix normalize_path_copy output buffer size
  fetch-pack: simplify add_sought_entry
  fast-import: simplify allocation in start_packfile
  write_untracked_extension: use FLEX_ALLOC helper
  prepare_{git,shell}_cmd: use argv_array
  use st_add and st_mult for allocation size computation
  convert trivial cases to FLEX_ARRAY macros
  use xmallocz to avoid size arithmetic
  convert trivial cases to ALLOC_ARRAY
  convert manual allocations to argv_array
  argv-array: add detach function
  add helpers for allocating flex-array structs
  harden REALLOC_ARRAY and xcalloc against size_t overflow
  ...

Author: gitster

Documentation/technical/api-argv-array.txt

@@ -56,3 +56,10 @@ Functions
 `argv_array_clear`::
 	Free all memory associated with the array and return it to the
 	initial, empty state.
+
+`argv_array_detach`::
+	Disconnect the `argv` member from the `argv_array` struct and
+	return it. The caller is responsible for freeing the memory used
+	by the array, and by the strings it references. After detaching,
+	the `argv_array` is in a reinitialized state and can be pushed
+	into again.

alias.c

@@ -23,7 +23,7 @@ int split_cmdline(char *cmdline, const char ***argv)
 	int src, dst, count = 0, size = 16;
 	char quoted = 0;
 
-	*argv = xmalloc(sizeof(**argv) * size);
+	ALLOC_ARRAY(*argv, size);
 
 	/* split alias_string */
 	(*argv)[count++] = cmdline;

archive.c

@@ -171,8 +171,8 @@ static void queue_directory(const unsigned char *sha1,
 		unsigned mode, int stage, struct archiver_context *c)
 {
 	struct directory *d;
-	size_t len = base->len + 1 + strlen(filename) + 1;
-	d = xmalloc(sizeof(*d) + len);
+	size_t len = st_add4(base->len, 1, strlen(filename), 1);
+	d = xmalloc(st_add(sizeof(*d), len));
 	d->up	   = c->bottom;
 	d->baselen = base->len;
 	d->mode	   = mode;

argv-array.c

@@ -74,3 +74,14 @@ void argv_array_clear(struct argv_array *array)
 	}
 	argv_array_init(array);
 }
+
+const char **argv_array_detach(struct argv_array *array)
+{
+	if (array->argv == empty_argv)
+		return xcalloc(1, sizeof(const char *));
+	else {
+		const char **ret = array->argv;
+		argv_array_init(array);
+		return ret;
+	}
+}

argv-array.h

@@ -20,5 +20,6 @@ void argv_array_pushl(struct argv_array *, ...);
 void argv_array_pushv(struct argv_array *, const char **);
 void argv_array_pop(struct argv_array *);
 void argv_array_clear(struct argv_array *);
+const char **argv_array_detach(struct argv_array *);
 
 #endif /* ARGV_ARRAY_H */

attr.c

@@ -93,9 +93,7 @@ static struct git_attr *git_attr_internal(const char *name, int len)
 	if (invalid_attr_name(name, len))
 		return NULL;
 
-	a = xmalloc(sizeof(*a) + len + 1);
-	memcpy(a->name, name, len);
-	a->name[len] = 0;
+	FLEX_ALLOC_MEM(a, name, name, len);
 	a->h = hval;
 	a->next = git_attr_hash[pos];
 	a->attr_nr = attr_nr++;
@@ -799,7 +797,7 @@ int git_all_attrs(const char *path, int *num, struct git_attr_check **check)
 			++count;
 	}
 	*num = count;
-	*check = xmalloc(sizeof(**check) * count);
+	ALLOC_ARRAY(*check, count);
 	j = 0;
 	for (i = 0; i < attr_nr; i++) {
 		const char *value = check_all_attr[i].value;

bisect.c

@@ -708,10 +708,10 @@ static struct commit *get_commit_reference(const unsigned char *sha1)
 
 static struct commit **get_bad_and_good_commits(int *rev_nr)
 {
-	int len = 1 + good_revs.nr;
-	struct commit **rev = xmalloc(len * sizeof(*rev));
+	struct commit **rev;
 	int i, n = 0;
 
+	ALLOC_ARRAY(rev, 1 + good_revs.nr);
 	rev[n++] = get_commit_reference(current_bad_oid->hash);
 	for (i = 0; i < good_revs.nr; i++)
 		rev[n++] = get_commit_reference(good_revs.sha1[i]);

builtin/apply.c

@@ -2632,7 +2632,7 @@ static void update_image(struct image *img,
 	insert_count = postimage->len;
 
 	/* Adjust the contents */
-	result = xmalloc(img->len + insert_count - remove_count + 1);
+	result = xmalloc(st_add3(st_sub(img->len, remove_count), insert_count, 1));
 	memcpy(result, img->buf, applied_at);
 	memcpy(result + applied_at, postimage->buf, postimage->len);
 	memcpy(result + applied_at + postimage->len,

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;
 }
 
@@ -2042,7 +2040,8 @@ static int prepare_lines(struct scoreboard *sb)
 	for (p = buf; p < end; p = get_next_line(p, end))
 		num++;
 
-	sb->lineno = lineno = xmalloc(sizeof(*sb->lineno) * (num + 1));
+	ALLOC_ARRAY(sb->lineno, num + 1);
+	lineno = sb->lineno;
 
 	for (p = buf; p < end; p = get_next_line(p, end))
 		*lineno++ = p - buf;

builtin/check-ref-format.c

@@ -20,7 +20,7 @@ static const char builtin_check_ref_format_usage[] =
  */
 static char *collapse_slashes(const char *refname)
 {
-	char *ret = xmalloc(strlen(refname) + 1);
+	char *ret = xmallocz(strlen(refname));
 	char ch;
 	char prev = '/';
 	char *cp = ret;