use COPY_ARRAY

Add a semantic patch for converting certain calls of memcpy(3) to
COPY_ARRAY() and apply that transformation to the code base.  The result
is
shorter and safer code.  For now only consider calls where source and
destination have the same type, or in other words: easy cases.

Signed-off-by: Rene Scharfe <l.s.r@web.de>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

diff --git a/builtin/mv.c b/builtin/mv.c
index a2014266b6b33d7940627777af9ae860c7850c2d..c13e49bf47ecfbb89af7fd1b9c2e9d090334e797 100644 (file)
--- a/builtin/mv.c
+++ b/builtin/mv.c
@@ -26,7 +26,7 @@ static const char **internal_copy_pathspec(const char *prefix,
        int i;
        const char **result;
        ALLOC_ARRAY(result, count + 1);
-       memcpy(result, pathspec, count * sizeof(const char *));
+       COPY_ARRAY(result, pathspec, count);
        result[count] = NULL;
        for (i = 0; i < count; i++) {
                int length = strlen(result[i]);

diff --git a/commit.c b/commit.c
index 2a90e37519f0b6e9de6e30ed57afe91822441ca3..9d3d7119e065af27aac5516251d05018a8393f67 100644 (file)
--- a/commit.c
+++ b/commit.c
@@ -931,7 +931,7 @@ static int remove_redundant(struct commit **array, int cnt)
        }
 
        /* Now collect the result */
-       memcpy(work, array, sizeof(*array) * cnt);
+       COPY_ARRAY(work, array, cnt);
        for (i = filled = 0; i < cnt; i++)
                if (!redundant[i])
                        array[filled++] = work[i];

diff --git a/contrib/coccinelle/array.cocci b/contrib/coccinelle/array.cocci
new file mode 100644 (file)
index 0000000..2d7f25d
--- /dev/null
+++ b/contrib/coccinelle/array.cocci
@@ -0,0 +1,26 @@
+@@
+type T;
+T *dst;
+T *src;
+expression n;
+@@
+- memcpy(dst, src, n * sizeof(*dst));
++ COPY_ARRAY(dst, src, n);
+
+@@
+type T;
+T *dst;
+T *src;
+expression n;
+@@
+- memcpy(dst, src, n * sizeof(*src));
++ COPY_ARRAY(dst, src, n);
+
+@@
+type T;
+T *dst;
+T *src;
+expression n;
+@@
+- memcpy(dst, src, n * sizeof(T));
++ COPY_ARRAY(dst, src, n);

diff --git a/pack-revindex.c b/pack-revindex.c
index 96d51c3467b9ef864f62962aa3567247338d2c3a..6bc7c940335cdf2d31cb38c2db6f8f6c985d3c3b 100644 (file)
--- a/pack-revindex.c
+++ b/pack-revindex.c
@@ -107,7 +107,7 @@ static void sort_revindex(struct revindex_entry *entries, unsigned n, off_t max)
         * we have to move it back from the temporary storage.
         */
        if (from != entries)
-               memcpy(entries, tmp, n * sizeof(*entries));
+               COPY_ARRAY(entries, tmp, n);
        free(tmp);
        free(pos);
 

diff --git a/pathspec.c b/pathspec.c
index 24e0dd52322baf4a507765ae0948c98f0ec30602..49a53607bb004e8ccc34e6a18eadc8dfc2e7879d 100644 (file)
--- a/pathspec.c
+++ b/pathspec.c
@@ -485,8 +485,7 @@ void copy_pathspec(struct pathspec *dst, const struct pathspec *src)
 {
        *dst = *src;
        ALLOC_ARRAY(dst->items, dst->nr);
-       memcpy(dst->items, src->items,
-              sizeof(struct pathspec_item) * dst->nr);
+       COPY_ARRAY(dst->items, src->items, dst->nr);
 }
 
 void clear_pathspec(struct pathspec *pathspec)

diff --git a/split-index.c b/split-index.c
index 3c75d4b9ce717fa92520881ef754485d068a3a60..35da553655bdf7b70519ecf529544796ca8185b5 100644 (file)
--- a/split-index.c
+++ b/split-index.c
@@ -83,8 +83,7 @@ void move_cache_to_base_index(struct index_state *istate)
        si->base->timestamp = istate->timestamp;
        ALLOC_GROW(si->base->cache, istate->cache_nr, si->base->cache_alloc);
        si->base->cache_nr = istate->cache_nr;
-       memcpy(si->base->cache, istate->cache,
-              sizeof(*istate->cache) * istate->cache_nr);
+       COPY_ARRAY(si->base->cache, istate->cache, istate->cache_nr);
        mark_base_index_entries(si->base);
        for (i = 0; i < si->base->cache_nr; i++)
                si->base->cache[i]->ce_flags &= ~CE_UPDATE_IN_BASE;
@@ -141,8 +140,7 @@ void merge_base_index(struct index_state *istate)
        istate->cache       = NULL;
        istate->cache_alloc = 0;
        ALLOC_GROW(istate->cache, istate->cache_nr, istate->cache_alloc);
-       memcpy(istate->cache, si->base->cache,
-              sizeof(*istate->cache) * istate->cache_nr);
+       COPY_ARRAY(istate->cache, si->base->cache, istate->cache_nr);
 
        si->nr_deletions = 0;
        si->nr_replacements = 0;