[1/3] mem-pool: add convenience functions for xstrdup and xstrndup

Commit Message

Johannes Schindelin via GitGitGadget Aug. 14, 2020, 3:02 a.m. UTC

From: Elijah Newren <[e-mail]>

fast-import had a special mem_pool_xstrdup() convenience function that I
want to be able to use from the new merge algorithm I am writing.  Move
it from fast-import to mem-pool, and also add a mem_pool_xstrndup()
while at it that I also want to use.

Signed-off-by: Elijah Newren <[e-mail]>
---
 fast-import.c | 12 ++----------
 mem-pool.c    | 23 +++++++++++++++++++++++
 mem-pool.h    |  6 ++++++
 3 files changed, 31 insertions(+), 10 deletions(-)

Comments

Eric Sunshine Aug. 14, 2020, 4:42 a.m. UTC | #1

On Thu, Aug 13, 2020 at 11:02 PM Elijah Newren via GitGitGadget
<[e-mail]> wrote:
> fast-import had a special mem_pool_xstrdup() convenience function that I
> want to be able to use from the new merge algorithm I am writing.  Move
> it from fast-import to mem-pool, and also add a mem_pool_xstrndup()
> while at it that I also want to use.
>
> Signed-off-by: Elijah Newren <[e-mail]>
> ---
> diff --git a/mem-pool.c b/mem-pool.c
> @@ -102,6 +102,29 @@ void *mem_pool_calloc(struct mem_pool *mem_pool, size_t count, size_t size)
> +char *mem_pool_xstrdup(struct mem_pool *pool, const char *str)
> +{
> +       size_t len = strlen(str) + 1;
> +       char *ret = mem_pool_alloc(pool, len);
> +
> +       if (!ret)
> +               die("Out of memory, mem_pool_xstrdup failed");

Nit: Not worth a re-roll, but I was wondering if it would make sense
to allow these to be localized (and follow current convention of not
capitalizing):

    die(_("mem_pool_xstrdup: out of memory"));

> +       return memcpy(ret, str, len);
> +}
> +
> +char *mem_pool_xstrndup(struct mem_pool *pool, const char *str, size_t len)
> +{
> +       size_t minlen = strnlen(str, len);
> +       char *ret = mem_pool_alloc(pool, minlen+1);
> +
> +       if (!ret)
> +               die("Out of memory, mem_pool_xstrndup failed");

Ditto.

> +
> +       ret[minlen] = '\0';
> +       return memcpy(ret, str, minlen);
> +}

Patch

diff --git a/fast-import.c b/fast-import.c
index ce47794db6..dd5b563950 100644
--- a/fast-import.c
+++ b/fast-import.c
@@ -526,14 +526,6 @@  static unsigned int hc_str(const char *s, size_t len)
 	return r;
 }
 
-static char *pool_strdup(const char *s)
-{
-	size_t len = strlen(s) + 1;
-	char *r = mem_pool_alloc(&fi_mem_pool, len);
-	memcpy(r, s, len);
-	return r;
-}
-
 static void insert_mark(struct mark_set *s, uintmax_t idnum, struct object_entry *oe)
 {
 	while ((idnum >> s->shift) >= 1024) {
@@ -615,7 +607,7 @@  static struct branch *new_branch(const char *name)
 		die("Branch name doesn't conform to GIT standards: %s", name);
 
 	b = mem_pool_calloc(&fi_mem_pool, 1, sizeof(struct branch));
-	b->name = pool_strdup(name);
+	b->name = mem_pool_xstrdup(&fi_mem_pool, name);
 	b->table_next_branch = branch_table[hc];
 	b->branch_tree.versions[0].mode = S_IFDIR;
 	b->branch_tree.versions[1].mode = S_IFDIR;
@@ -2806,7 +2798,7 @@  static void parse_new_tag(const char *arg)
 
 	t = mem_pool_alloc(&fi_mem_pool, sizeof(struct tag));
 	memset(t, 0, sizeof(struct tag));
-	t->name = pool_strdup(arg);
+	t->name = mem_pool_xstrdup(&fi_mem_pool, arg);
 	if (last_tag)
 		last_tag->next_tag = t;
 	else
diff --git a/mem-pool.c b/mem-pool.c
index a2841a4a9a..3a8c54d9df 100644
--- a/mem-pool.c
+++ b/mem-pool.c
@@ -102,6 +102,29 @@  void *mem_pool_calloc(struct mem_pool *mem_pool, size_t count, size_t size)
 	return r;
 }
 
+char *mem_pool_xstrdup(struct mem_pool *pool, const char *str)
+{
+	size_t len = strlen(str) + 1;
+	char *ret = mem_pool_alloc(pool, len);
+
+	if (!ret)
+		die("Out of memory, mem_pool_xstrdup failed");
+
+	return memcpy(ret, str, len);
+}
+
+char *mem_pool_xstrndup(struct mem_pool *pool, const char *str, size_t len)
+{
+	size_t minlen = strnlen(str, len);
+	char *ret = mem_pool_alloc(pool, minlen+1);
+
+	if (!ret)
+		die("Out of memory, mem_pool_xstrndup failed");
+
+	ret[minlen] = '\0';
+	return memcpy(ret, str, minlen);
+}
+
 int mem_pool_contains(struct mem_pool *mem_pool, void *mem)
 {
 	struct mp_block *p;
diff --git a/mem-pool.h b/mem-pool.h
index 999d3c3a52..fcaa2d462b 100644
--- a/mem-pool.h
+++ b/mem-pool.h
@@ -41,6 +41,12 @@  void *mem_pool_alloc(struct mem_pool *pool, size_t len);
  */
 void *mem_pool_calloc(struct mem_pool *pool, size_t count, size_t size);
 
+/*
+ * Allocate memory from the memory pool and copy str into it.
+ */
+char *mem_pool_xstrdup(struct mem_pool *pool, const char *str);
+char *mem_pool_xstrndup(struct mem_pool *pool, const char *str, size_t len);
+
 /*
  * Move the memory associated with the 'src' pool to the 'dst' pool. The 'src'
  * pool will be empty and not contain any memory. It still needs to be free'd