Convert memcpy(a,b,20) to hashcpy(a,b).

This abstracts away the size of the hash values when copying them
from memory location to memory location, much as the introduction
of hashcmp abstracted away hash value comparsion.

A few call sites were using char* rather than unsigned char* so
I added the cast rather than open hashcpy to be void*.  This is a
reasonable tradeoff as most call sites already use unsigned char*
and the existing hashcmp is also declared to be unsigned char*.

[jc: Splitted the patch to "master" part, to be followed by a
 patch for merge-recursive.c which is not in "master" yet.

 Fixed the cast in the latter hunk to combine-diff.c which was
 wrong in the original.

 Also converted ones left-over in combine-diff.c, diff-lib.c and
 upload-pack.c ]

Signed-off-by: Shawn O. Pearce <spearce@spearce.org>
Signed-off-by: Junio C Hamano <junkio@cox.net>

34 files changed, 81 insertions, 78 deletions

diff --git a/blame.c b/blame.c
index c253b9ca45..5a8af72623 100644
--- a/blame.c
+++ b/blame.c
@@ -176,7 +176,7 @@ static int get_blob_sha1(struct tree *t, const char *pathname,
 	if (i == 20)
 		return -1;
 
-	memcpy(sha1, blob_sha1, 20);
+	hashcpy(sha1, blob_sha1);
 	return 0;
 }
 
@@ -191,7 +191,7 @@ static int get_blob_sha1_internal(const unsigned char *sha1, const char *base,
 	    strcmp(blame_file + baselen, pathname))
 		return -1;
 
-	memcpy(blob_sha1, sha1, 20);
+	hashcpy(blob_sha1, sha1);
 	return -1;
 }
 
diff --git a/builtin-diff.c b/builtin-diff.c
index 874f773421..a6590205e8 100644
--- a/builtin-diff.c
+++ b/builtin-diff.c
@@ -192,7 +192,7 @@ static int builtin_diff_combined(struct rev_info *revs,
 	parent = xmalloc(ents * sizeof(*parent));
 	/* Again, the revs are all reverse */
 	for (i = 0; i < ents; i++)
-		memcpy(parent + i, ent[ents - 1 - i].item->sha1, 20);
+		hashcpy((unsigned char*)parent + i, ent[ents - 1 - i].item->sha1);
 	diff_tree_combined(parent[0], parent + 1, ents - 1,
 			   revs->dense_combined_merges, revs);
 	return 0;
@@ -290,7 +290,7 @@ int cmd_diff(int argc, const char **argv, const char *prefix)
 		if (obj->type == OBJ_BLOB) {
 			if (2 <= blobs)
 				die("more than two blobs given: '%s'", name);
-			memcpy(blob[blobs].sha1, obj->sha1, 20);
+			hashcpy(blob[blobs].sha1, obj->sha1);
 			blob[blobs].name = name;
 			blobs++;
 			continue;
diff --git a/builtin-pack-objects.c b/builtin-pack-objects.c
index f19f0d6046..46f524dfc3 100644
--- a/builtin-pack-objects.c
+++ b/builtin-pack-objects.c
@@ -534,7 +534,7 @@ static int add_object_entry(const unsigned char *sha1, unsigned hash, int exclud
 	entry = objects + idx;
 	nr_objects = idx + 1;
 	memset(entry, 0, sizeof(*entry));
-	memcpy(entry->sha1, sha1, 20);
+	hashcpy(entry->sha1, sha1);
 	entry->hash = hash;
 
 	if (object_ix_hashsz * 3 <= nr_objects * 4)
@@ -649,7 +649,7 @@ static struct pbase_tree_cache *pbase_tree_get(const unsigned char *sha1)
 		free(ent->tree_data);
 		nent = ent;
 	}
-	memcpy(nent->sha1, sha1, 20);
+	hashcpy(nent->sha1, sha1);
 	nent->tree_data = data;
 	nent->tree_size = size;
 	nent->ref = 1;
@@ -799,7 +799,7 @@ static void add_preferred_base(unsigned char *sha1)
 	it->next = pbase_tree;
 	pbase_tree = it;
 
-	memcpy(it->pcache.sha1, tree_sha1, 20);
+	hashcpy(it->pcache.sha1, tree_sha1);
 	it->pcache.tree_data = data;
 	it->pcache.tree_size = size;
 }
diff --git a/builtin-read-tree.c b/builtin-read-tree.c
index 53087faf7a..c1867d2a00 100644
--- a/builtin-read-tree.c
+++ b/builtin-read-tree.c
@@ -53,7 +53,7 @@ static void prime_cache_tree_rec(struct cache_tree *it, struct tree *tree)
 	struct name_entry entry;
 	int cnt;
 
-	memcpy(it->sha1, tree->object.sha1, 20);
+	hashcpy(it->sha1, tree->object.sha1);
 	desc.buf = tree->buffer;
 	desc.size = tree->size;
 	cnt = 0;
diff --git a/builtin-unpack-objects.c b/builtin-unpack-objects.c
index f0ae5c987a..ca0ebc2585 100644
--- a/builtin-unpack-objects.c
+++ b/builtin-unpack-objects.c
@@ -95,7 +95,7 @@ static void add_delta_to_list(unsigned char *base_sha1, void *delta, unsigned lo
 {
 	struct delta_info *info = xmalloc(sizeof(*info));
 
-	memcpy(info->base_sha1, base_sha1, 20);
+	hashcpy(info->base_sha1, base_sha1);
 	info->size = size;
 	info->delta = delta;
 	info->next = delta_list;
@@ -173,7 +173,7 @@ static int unpack_delta_entry(unsigned long delta_size)
 	unsigned char base_sha1[20];
 	int result;
 
-	memcpy(base_sha1, fill(20), 20);
+	hashcpy(base_sha1, fill(20));
 	use(20);
 
 	delta_data = get_data(delta_size);
diff --git a/builtin-update-index.c b/builtin-update-index.c
index 5dd91af180..8675126471 100644
--- a/builtin-update-index.c
+++ b/builtin-update-index.c
@@ -142,7 +142,7 @@ static int add_cacheinfo(unsigned int mode, const unsigned char *sha1,
 	size = cache_entry_size(len);
 	ce = xcalloc(1, size);
 
-	memcpy(ce->sha1, sha1, 20);
+	hashcpy(ce->sha1, sha1);
 	memcpy(ce->name, path, len);
 	ce->ce_flags = create_ce_flags(len, stage);
 	ce->ce_mode = create_ce_mode(mode);
@@ -333,7 +333,7 @@ static struct cache_entry *read_one_ent(const char *which,
 	size = cache_entry_size(namelen);
 	ce = xcalloc(1, size);
 
-	memcpy(ce->sha1, sha1, 20);
+	hashcpy(ce->sha1, sha1);
 	memcpy(ce->name, path, namelen);
 	ce->ce_flags = create_ce_flags(namelen, stage);
 	ce->ce_mode = create_ce_mode(mode);
diff --git a/builtin-write-tree.c b/builtin-write-tree.c
index ca06149f18..50670dc7bf 100644
--- a/builtin-write-tree.c
+++ b/builtin-write-tree.c
@@ -50,10 +50,10 @@ int write_tree(unsigned char *sha1, int missing_ok, const char *prefix)
 	if (prefix) {
 		struct cache_tree *subtree =
 			cache_tree_find(active_cache_tree, prefix);
-		memcpy(sha1, subtree->sha1, 20);
+		hashcpy(sha1, subtree->sha1);
 	}
 	else
-		memcpy(sha1, active_cache_tree->sha1, 20);
+		hashcpy(sha1, active_cache_tree->sha1);
 
 	rollback_lock_file(lock_file);
 
diff --git a/cache-tree.c b/cache-tree.c
index d9f7e1e3dd..323c68a670 100644
--- a/cache-tree.c
+++ b/cache-tree.c
@@ -335,7 +335,7 @@ static int update_one(struct cache_tree *it,
 		offset += sprintf(buffer + offset,
 				  "%o %.*s", mode, entlen, path + baselen);
 		buffer[offset++] = 0;
-		memcpy(buffer + offset, sha1, 20);
+		hashcpy((unsigned char*)buffer + offset, sha1);
 		offset += 20;
 
 #if DEBUG
@@ -412,7 +412,7 @@ static void *write_one(struct cache_tree *it,
 #endif
 
 	if (0 <= it->entry_count) {
-		memcpy(buffer + *offset, it->sha1, 20);
+		hashcpy((unsigned char*)buffer + *offset, it->sha1);
 		*offset += 20;
 	}
 	for (i = 0; i < it->subtree_nr; i++) {
@@ -478,7 +478,7 @@ static struct cache_tree *read_one(const char **buffer, unsigned long *size_p)
 	if (0 <= it->entry_count) {
 		if (size < 20)
 			goto free_return;
-		memcpy(it->sha1, buf, 20);
+		hashcpy(it->sha1, (unsigned char*)buf);
 		buf += 20;
 		size -= 20;
 	}
diff --git a/cache.h b/cache.h
index 08d6a91279..cc3f00c2b8 100644
--- a/cache.h
+++ b/cache.h
@@ -218,6 +218,10 @@ static inline int hashcmp(const unsigned char *sha1, const unsigned char *sha2)
 {
 	return memcmp(sha1, sha2, 20);
 }
+static inline void hashcpy(unsigned char *sha_dst, const unsigned char *sha_src)
+{
+	memcpy(sha_dst, sha_src, 20);
+}
 
 int git_mkstemp(char *path, size_t n, const char *template);
 
diff --git a/combine-diff.c b/combine-diff.c
index 0682acd50d..46d9121baf 100644
--- a/combine-diff.c
+++ b/combine-diff.c
@@ -31,9 +31,9 @@ static struct combine_diff_path *intersect_paths(struct combine_diff_path *curr,
 			memset(p->parent, 0,
 			       sizeof(p->parent[0]) * num_parent);
 
-			memcpy(p->sha1, q->queue[i]->two->sha1, 20);
+			hashcpy(p->sha1, q->queue[i]->two->sha1);
 			p->mode = q->queue[i]->two->mode;
-			memcpy(p->parent[n].sha1, q->queue[i]->one->sha1, 20);
+			hashcpy(p->parent[n].sha1, q->queue[i]->one->sha1);
 			p->parent[n].mode = q->queue[i]->one->mode;
 			p->parent[n].status = q->queue[i]->status;
 			*tail = p;
@@ -56,8 +56,7 @@ static struct combine_diff_path *intersect_paths(struct combine_diff_path *curr,
 			len = strlen(path);
 			if (len == p->len && !memcmp(path, p->path, len)) {
 				found = 1;
-				memcpy(p->parent[n].sha1,
-				       q->queue[i]->one->sha1, 20);
+				hashcpy(p->parent[n].sha1, q->queue[i]->one->sha1);
 				p->parent[n].mode = q->queue[i]->one->mode;
 				p->parent[n].status = q->queue[i]->status;
 				break;
@@ -927,6 +926,7 @@ void diff_tree_combined_merge(const unsigned char *sha1,
 	for (parents = commit->parents, num_parent = 0;
 	     parents;
 	     parents = parents->next, num_parent++)
-		memcpy(parent + num_parent, parents->item->object.sha1, 20);
+		hashcpy((unsigned char*)(parent + num_parent),
+			parents->item->object.sha1);
 	diff_tree_combined(sha1, parent, num_parent, dense, rev);
 }
diff --git a/connect.c b/connect.c
index 7a6a73f2a3..e501ccce25 100644
--- a/connect.c
+++ b/connect.c
@@ -77,7 +77,7 @@ struct ref **get_remote_heads(int in, struct ref **list,
 		if (nr_match && !path_match(name, nr_match, match))
 			continue;
 		ref = xcalloc(1, sizeof(*ref) + len - 40);
-		memcpy(ref->old_sha1, old_sha1, 20);
+		hashcpy(ref->old_sha1, old_sha1);
 		memcpy(ref->name, buffer + 41, len - 40);
 		*list = ref;
 		list = &ref->next;
@@ -208,7 +208,7 @@ static struct ref *try_explicit_object_name(const char *name)
 	len = strlen(name) + 1;
 	ref = xcalloc(1, sizeof(*ref) + len);
 	memcpy(ref->name, name, len);
-	memcpy(ref->new_sha1, sha1, 20);
+	hashcpy(ref->new_sha1, sha1);
 	return ref;
 }
 
@@ -318,7 +318,7 @@ int match_refs(struct ref *src, struct ref *dst, struct ref ***dst_tail,
 			int len = strlen(src->name) + 1;
 			dst_peer = xcalloc(1, sizeof(*dst_peer) + len);
 			memcpy(dst_peer->name, src->name, len);
-			memcpy(dst_peer->new_sha1, src->new_sha1, 20);
+			hashcpy(dst_peer->new_sha1, src->new_sha1);
 			link_dst_tail(dst_peer, dst_tail);
 		}
 		dst_peer->peer_ref = src;
diff --git a/convert-objects.c b/convert-objects.c
index 4e7ff7517f..631678b08a 100644
--- a/convert-objects.c
+++ b/convert-objects.c
@@ -23,7 +23,7 @@ static struct entry * convert_entry(unsigned char *sha1);
 static struct entry *insert_new(unsigned char *sha1, int pos)
 {
 	struct entry *new = xcalloc(1, sizeof(struct entry));
-	memcpy(new->old_sha1, sha1, 20);
+	hashcpy(new->old_sha1, sha1);
 	memmove(convert + pos + 1, convert + pos, (nr_convert - pos) * sizeof(struct entry *));
 	convert[pos] = new;
 	nr_convert++;
@@ -54,7 +54,7 @@ static struct entry *lookup_entry(unsigned char *sha1)
 static void convert_binary_sha1(void *buffer)
 {
 	struct entry *entry = convert_entry(buffer);
-	memcpy(buffer, entry->new_sha1, 20);
+	hashcpy(buffer, entry->new_sha1);
 }
 
 static void convert_ascii_sha1(void *buffer)
@@ -104,7 +104,7 @@ static int write_subdirectory(void *buffer, unsigned long size, const char *base
 		if (!slash) {
 			newlen += sprintf(new + newlen, "%o %s", mode, path);
 			new[newlen++] = '\0';
-			memcpy(new + newlen, (char *) buffer + len - 20, 20);
+			hashcpy((unsigned char*)new + newlen, (unsigned char *) buffer + len - 20);
 			newlen += 20;
 
 			used += len;
diff --git a/csum-file.c b/csum-file.c
index e2278897d0..b7174c6c05 100644
--- a/csum-file.c
+++ b/csum-file.c
@@ -38,7 +38,7 @@ int sha1close(struct sha1file *f, unsigned char *result, int update)
 	}
 	SHA1_Final(f->buffer, &f->ctx);
 	if (result)
-		memcpy(result, f->buffer, 20);
+		hashcpy(result, f->buffer);
 	if (update)
 		sha1flush(f, 20);
 	if (close(f->fd))
diff --git a/diff-lib.c b/diff-lib.c
index 3e4b3b96b7..2fc41263ae 100644
--- a/diff-lib.c
+++ b/diff-lib.c
@@ -66,8 +66,7 @@ int run_diff_files(struct rev_info *revs, int silent_on_removed)
 				if (2 <= stage) {
 					int mode = ntohl(nce->ce_mode);
 					num_compare_stages++;
-					memcpy(dpath->parent[stage-2].sha1,
-					       nce->sha1, 20);
+					hashcpy(dpath->parent[stage-2].sha1, nce->sha1);
 					dpath->parent[stage-2].mode =
 						canon_mode(mode);
 					dpath->parent[stage-2].status =
diff --git a/diff.c b/diff.c
index da7cca1952..ca171e8e69 100644
--- a/diff.c
+++ b/diff.c
@@ -1101,7 +1101,7 @@ void fill_filespec(struct diff_filespec *spec, const unsigned char *sha1,
 {
 	if (mode) {
 		spec->mode = canon_mode(mode);
-		memcpy(spec->sha1, sha1, 20);
+		hashcpy(spec->sha1, sha1);
 		spec->sha1_valid = !is_null_sha1(sha1);
 	}
 }
@@ -1194,7 +1194,7 @@ static struct sha1_size_cache *locate_size_cache(unsigned char *sha1,
 			sizeof(*sha1_size_cache));
 	e = xmalloc(sizeof(struct sha1_size_cache));
 	sha1_size_cache[first] = e;
-	memcpy(e->sha1, sha1, 20);
+	hashcpy(e->sha1, sha1);
 	e->size = size;
 	return e;
 }
@@ -1516,7 +1516,7 @@ static void diff_fill_sha1_info(struct diff_filespec *one)
 		}
 	}
 	else
-		memset(one->sha1, 0, 20);
+		hashclr(one->sha1);
 }
 
 static void run_diff(struct diff_filepair *p, struct diff_options *o)
diff --git a/fetch-pack.c b/fetch-pack.c
index e18c1489a1..377feded1c 100644
--- a/fetch-pack.c
+++ b/fetch-pack.c
@@ -404,7 +404,7 @@ static int everything_local(struct ref **refs, int nr_match, char **match)
 			continue;
 		}
 
-		memcpy(ref->new_sha1, local, 20);
+		hashcpy(ref->new_sha1, local);
 		if (!verbose)
 			continue;
 		fprintf(stderr,
diff --git a/fetch.c b/fetch.c
index aeb6bf2639..ef60b045ea 100644
--- a/fetch.c
+++ b/fetch.c
@@ -84,7 +84,7 @@ static int process_commit(struct commit *commit)
 	if (commit->object.flags & COMPLETE)
 		return 0;
 
-	memcpy(current_commit_sha1, commit->object.sha1, 20);
+	hashcpy(current_commit_sha1, commit->object.sha1);
 
 	pull_say("walk %s\n", sha1_to_hex(commit->object.sha1));
 
diff --git a/fsck-objects.c b/fsck-objects.c
index 31e00d84b3..ae0ec8d039 100644
--- a/fsck-objects.c
+++ b/fsck-objects.c
@@ -356,7 +356,7 @@ static void add_sha1_list(unsigned char *sha1, unsigned long ino)
 	int nr;
 
 	entry->ino = ino;
-	memcpy(entry->sha1, sha1, 20);
+	hashcpy(entry->sha1, sha1);
 	nr = sha1_list.nr;
 	if (nr == MAX_SHA1_ENTRIES) {
 		fsck_sha1_list();
diff --git a/http-fetch.c b/http-fetch.c
index d1f74b443b..7619b338fe 100644
--- a/http-fetch.c
+++ b/http-fetch.c
@@ -393,7 +393,7 @@ void prefetch(unsigned char *sha1)
 	char *filename = sha1_file_name(sha1);
 
 	newreq = xmalloc(sizeof(*newreq));
-	memcpy(newreq->sha1, sha1, 20);
+	hashcpy(newreq->sha1, sha1);
 	newreq->repo = alt;
 	newreq->url = NULL;
 	newreq->local = -1;
diff --git a/http-push.c b/http-push.c
index 48497797f1..ebfcc73a9e 100644
--- a/http-push.c
+++ b/http-push.c
@@ -1874,7 +1874,7 @@ static int one_local_ref(const char *refname, const unsigned char *sha1)
 	struct ref *ref;
 	int len = strlen(refname) + 1;
 	ref = xcalloc(1, sizeof(*ref) + len);
-	memcpy(ref->new_sha1, sha1, 20);
+	hashcpy(ref->new_sha1, sha1);
 	memcpy(ref->name, refname, len);
 	*local_tail = ref;
 	local_tail = &ref->next;
@@ -1909,7 +1909,7 @@ static void one_remote_ref(char *refname)
 	}
 
 	ref = xcalloc(1, sizeof(*ref) + len);
-	memcpy(ref->old_sha1, remote_sha1, 20);
+	hashcpy(ref->old_sha1, remote_sha1);
 	memcpy(ref->name, refname, len);
 	*remote_tail = ref;
 	remote_tail = &ref->next;
@@ -2445,7 +2445,7 @@ int main(int argc, char **argv)
 				continue;
 			}
 		}
-		memcpy(ref->new_sha1, ref->peer_ref->new_sha1, 20);
+		hashcpy(ref->new_sha1, ref->peer_ref->new_sha1);
 		if (is_zero_sha1(ref->new_sha1)) {
 			error("cannot happen anymore");
 			rc = -3;
diff --git a/index-pack.c b/index-pack.c
index 96ea687463..80bc6cb45b 100644
--- a/index-pack.c
+++ b/index-pack.c
@@ -161,7 +161,7 @@ static void *unpack_raw_entry(unsigned long offset,
 	case OBJ_DELTA:
 		if (pos + 20 >= pack_limit)
 			bad_object(offset, "object extends past end of pack");
-		memcpy(delta_base, pack_base + pos, 20);
+		hashcpy(delta_base, pack_base + pos);
 		pos += 20;
 		/* fallthru */
 	case OBJ_COMMIT:
@@ -304,7 +304,7 @@ static void parse_pack_objects(void)
 		if (obj->type == OBJ_DELTA) {
 			struct delta_entry *delta = &deltas[nr_deltas++];
 			delta->obj = obj;
-			memcpy(delta->base_sha1, base_sha1, 20);
+			hashcpy(delta->base_sha1, base_sha1);
 		} else
 			sha1_object(data, data_size, obj->type, obj->sha1);
 		free(data);
diff --git a/mktree.c b/mktree.c
index 93241385e4..56205d1e00 100644
--- a/mktree.c
+++ b/mktree.c
@@ -30,7 +30,7 @@ static void append_to_tree(unsigned mode, unsigned char *sha1, char *path)
 	ent = entries[used++] = xmalloc(sizeof(**entries) + len + 1);
 	ent->mode = mode;
 	ent->len = len;
-	memcpy(ent->sha1, sha1, 20);
+	hashcpy(ent->sha1, sha1);
 	memcpy(ent->name, path, len+1);
 }
 
@@ -64,7 +64,7 @@ static void write_tree(unsigned char *sha1)
 		offset += sprintf(buffer + offset, "%o ", ent->mode);
 		offset += sprintf(buffer + offset, "%s", ent->name);
 		buffer[offset++] = 0;
-		memcpy(buffer + offset, ent->sha1, 20);
+		hashcpy((unsigned char*)buffer + offset, ent->sha1);
 		offset += 20;
 	}
 	write_sha1_file(buffer, offset, tree_type, sha1);
diff --git a/object.c b/object.c
index fdcfff7c86..60bf16b902 100644
--- a/object.c
+++ b/object.c
@@ -91,7 +91,7 @@ void created_object(const unsigned char *sha1, struct object *obj)
 	obj->used = 0;
 	obj->type = OBJ_NONE;
 	obj->flags = 0;
-	memcpy(obj->sha1, sha1, 20);
+	hashcpy(obj->sha1, sha1);
 
 	if (obj_hash_size - 1 <= nr_objs * 2)
 		grow_object_hash();
diff --git a/patch-id.c b/patch-id.c
index 3b4c80f764..086d2d9c68 100644
--- a/patch-id.c
+++ b/patch-id.c
@@ -47,7 +47,7 @@ static void generate_id_list(void)
 
 		if (!get_sha1_hex(p, n)) {
 			flush_current_id(patchlen, sha1, &ctx);
-			memcpy(sha1, n, 20);
+			hashcpy(sha1, n);
 			patchlen = 0;
 			continue;
 		}
diff --git a/receive-pack.c b/receive-pack.c
index 81e91909b8..201531626c 100644
--- a/receive-pack.c
+++ b/receive-pack.c
@@ -247,8 +247,8 @@ static void read_head_info(void)
 				report_status = 1;
 		}
 		cmd = xmalloc(sizeof(struct command) + len - 80);
-		memcpy(cmd->old_sha1, old_sha1, 20);
-		memcpy(cmd->new_sha1, new_sha1, 20);
+		hashcpy(cmd->old_sha1, old_sha1);
+		hashcpy(cmd->new_sha1, new_sha1);
 		memcpy(cmd->ref_name, line + 82, len - 81);
 		cmd->error_string = "n/a (unpacker error)";
 		cmd->next = NULL;
diff --git a/refs.c b/refs.c
index 17cd0cef3c..e70ef0ae0f 100644
--- a/refs.c
+++ b/refs.c
@@ -29,7 +29,7 @@ const char *resolve_ref(const char *path, unsigned char *sha1, int reading)
 		if (lstat(path, &st) < 0) {
 			if (reading || errno != ENOENT)
 				return NULL;
-			memset(sha1, 0, 20);
+			hashclr(sha1);
 			return path;
 		}
 
diff --git a/revision.c b/revision.c
index 5a91d06b98..1d89d72738 100644
--- a/revision.c
+++ b/revision.c
@@ -496,7 +496,7 @@ static int add_parents_only(struct rev_info *revs, const char *arg, int flags)
 		it = get_reference(revs, arg, sha1, 0);
 		if (it->type != OBJ_TAG)
 			break;
-		memcpy(sha1, ((struct tag*)it)->tagged->sha1, 20);
+		hashcpy(sha1, ((struct tag*)it)->tagged->sha1);
 	}
 	if (it->type != OBJ_COMMIT)
 		return 0;
diff --git a/send-pack.c b/send-pack.c
index f7c0cfc6f6..fd79a61923 100644
--- a/send-pack.c
+++ b/send-pack.c
@@ -185,7 +185,7 @@ static int one_local_ref(const char *refname, const unsigned char *sha1)
 	struct ref *ref;
 	int len = strlen(refname) + 1;
 	ref = xcalloc(1, sizeof(*ref) + len);
-	memcpy(ref->new_sha1, sha1, 20);
+	hashcpy(ref->new_sha1, sha1);
 	memcpy(ref->name, refname, len);
 	*local_tail = ref;
 	local_tail = &ref->next;
@@ -310,7 +310,7 @@ static int send_pack(int in, int out, int nr_refspec, char **refspec)
 				continue;
 			}
 		}
-		memcpy(ref->new_sha1, ref->peer_ref->new_sha1, 20);
+		hashcpy(ref->new_sha1, ref->peer_ref->new_sha1);
 		if (is_zero_sha1(ref->new_sha1)) {
 			error("cannot happen anymore");
 			ret = -3;
diff --git a/sha1_file.c b/sha1_file.c
index 066cff1fa6..769a80984d 100644
--- a/sha1_file.c
+++ b/sha1_file.c
@@ -540,7 +540,7 @@ struct packed_git *add_packed_git(char *path, int path_len, int local)
 	p->pack_use_cnt = 0;
 	p->pack_local = local;
 	if ((path_len > 44) && !get_sha1_hex(path + path_len - 44, sha1))
-		memcpy(p->sha1, sha1, 20);
+		hashcpy(p->sha1, sha1);
 	return p;
 }
 
@@ -571,7 +571,7 @@ struct packed_git *parse_pack_index_file(const unsigned char *sha1, char *idx_pa
 	p->pack_base = NULL;
 	p->pack_last_used = 0;
 	p->pack_use_cnt = 0;
-	memcpy(p->sha1, sha1, 20);
+	hashcpy(p->sha1, sha1);
 	return p;
 }
 
@@ -953,7 +953,7 @@ int check_reuse_pack_delta(struct packed_git *p, unsigned long offset,
 	ptr = unpack_object_header(p, ptr, kindp, sizep);
 	if (*kindp != OBJ_DELTA)
 		goto done;
-	memcpy(base, (unsigned char *) p->pack_base + ptr, 20);
+	hashcpy(base, (unsigned char *) p->pack_base + ptr);
 	status = 0;
  done:
 	unuse_packed_git(p);
@@ -981,7 +981,7 @@ void packed_object_info_detail(struct pack_entry *e,
 		if (p->pack_size <= offset + 20)
 			die("pack file %s records an incomplete delta base",
 			    p->pack_name);
-		memcpy(base_sha1, pack, 20);
+		hashcpy(base_sha1, pack);
 		do {
 			struct pack_entry base_ent;
 			unsigned long junk;
@@ -1201,7 +1201,7 @@ int nth_packed_object_sha1(const struct packed_git *p, int n,
 	void *index = p->index_base + 256;
 	if (n < 0 || num_packed_objects(p) <= n)
 		return -1;
-	memcpy(sha1, (char *) index + (24 * n) + 4, 20);
+	hashcpy(sha1, (unsigned char *) index + (24 * n) + 4);
 	return 0;
 }
 
@@ -1218,7 +1218,7 @@ int find_pack_entry_one(const unsigned char *sha1,
 		int cmp = hashcmp((unsigned char *)index + (24 * mi) + 4, sha1);
 		if (!cmp) {
 			e->offset = ntohl(*((unsigned int *) ((char *) index + (24 * mi))));
-			memcpy(e->sha1, sha1, 20);
+			hashcpy(e->sha1, sha1);
 			e->p = p;
 			return 1;
 		}
@@ -1331,7 +1331,7 @@ void *read_object_with_reference(const unsigned char *sha1,
 	unsigned long isize;
 	unsigned char actual_sha1[20];
 
-	memcpy(actual_sha1, sha1, 20);
+	hashcpy(actual_sha1, sha1);
 	while (1) {
 		int ref_length = -1;
 		const char *ref_type = NULL;
@@ -1342,7 +1342,7 @@ void *read_object_with_reference(const unsigned char *sha1,
 		if (!strcmp(type, required_type)) {
 			*size = isize;
 			if (actual_sha1_return)
-				memcpy(actual_sha1_return, actual_sha1, 20);
+				hashcpy(actual_sha1_return, actual_sha1);
 			return buffer;
 		}
 		/* Handle references */
@@ -1537,7 +1537,7 @@ int write_sha1_file(void *buf, unsigned long len, const char *type, unsigned cha
 	 */
 	filename = write_sha1_file_prepare(buf, len, type, sha1, hdr, &hdrlen);
 	if (returnsha1)
-		memcpy(returnsha1, sha1, 20);
+		hashcpy(returnsha1, sha1);
 	if (has_sha1_file(sha1))
 		return 0;
 	fd = open(filename, O_RDONLY);
diff --git a/sha1_name.c b/sha1_name.c
index e9eb6ce882..89b9e3b77a 100644
--- a/sha1_name.c
+++ b/sha1_name.c
@@ -103,7 +103,7 @@ static int find_short_packed_object(int len, const unsigned char *match, unsigne
 				    !match_sha(len, match, next)) {
 					/* unique within this pack */
 					if (!found) {
-						memcpy(found_sha1, now, 20);
+						hashcpy(found_sha1, now);
 						found++;
 					}
 					else if (hashcmp(found_sha1, now)) {
@@ -120,7 +120,7 @@ static int find_short_packed_object(int len, const unsigned char *match, unsigne
 		}
 	}
 	if (found == 1)
-		memcpy(sha1, found_sha1, 20);
+		hashcpy(sha1, found_sha1);
 	return found;
 }
 
@@ -140,13 +140,13 @@ static int find_unique_short_object(int len, char *canonical,
 	if (1 < has_unpacked || 1 < has_packed)
 		return SHORT_NAME_AMBIGUOUS;
 	if (has_unpacked != has_packed) {
-		memcpy(sha1, (has_packed ? packed_sha1 : unpacked_sha1), 20);
+		hashcpy(sha1, (has_packed ? packed_sha1 : unpacked_sha1));
 		return 0;
 	}
 	/* Both have unique ones -- do they match? */
 	if (hashcmp(packed_sha1, unpacked_sha1))
 		return SHORT_NAME_AMBIGUOUS;
-	memcpy(sha1, packed_sha1, 20);
+	hashcpy(sha1, packed_sha1);
 	return 0;
 }
 
@@ -320,13 +320,13 @@ static int get_parent(const char *name, int len,
 	if (parse_commit(commit))
 		return -1;
 	if (!idx) {
-		memcpy(result, commit->object.sha1, 20);
+		hashcpy(result, commit->object.sha1);
 		return 0;
 	}
 	p = commit->parents;
 	while (p) {
 		if (!--idx) {
-			memcpy(result, p->item->object.sha1, 20);
+			hashcpy(result, p->item->object.sha1);
 			return 0;
 		}
 		p = p->next;
@@ -347,9 +347,9 @@ static int get_nth_ancestor(const char *name, int len,
 
 		if (!commit || parse_commit(commit) || !commit->parents)
 			return -1;
-		memcpy(sha1, commit->parents->item->object.sha1, 20);
+		hashcpy(sha1, commit->parents->item->object.sha1);
 	}
-	memcpy(result, sha1, 20);
+	hashcpy(result, sha1);
 	return 0;
 }
 
@@ -401,7 +401,7 @@ static int peel_onion(const char *name, int len, unsigned char *sha1)
 		o = deref_tag(o, name, sp - name - 2);
 		if (!o || (!o->parsed && !parse_object(o->sha1)))
 			return -1;
-		memcpy(sha1, o->sha1, 20);
+		hashcpy(sha1, o->sha1);
 	}
 	else {
 		/* At this point, the syntax look correct, so
@@ -413,7 +413,7 @@ static int peel_onion(const char *name, int len, unsigned char *sha1)
 			if (!o || (!o->parsed && !parse_object(o->sha1)))
 				return -1;
 			if (o->type == expected_type) {
-				memcpy(sha1, o->sha1, 20);
+				hashcpy(sha1, o->sha1);
 				return 0;
 			}
 			if (o->type == OBJ_TAG)
@@ -520,7 +520,7 @@ int get_sha1(const char *name, unsigned char *sha1)
 			    memcmp(ce->name, cp, namelen))
 				break;
 			if (ce_stage(ce) == stage) {
-				memcpy(sha1, ce->sha1, 20);
+				hashcpy(sha1, ce->sha1);
 				return 0;
 			}
 			pos++;
diff --git a/tree-walk.c b/tree-walk.c
index 3f83e98f3a..14cc5aea6c 100644
--- a/tree-walk.c
+++ b/tree-walk.c
@@ -179,7 +179,7 @@ static int find_tree_entry(struct tree_desc *t, const char *name, unsigned char
 		if (cmp < 0)
 			break;
 		if (entrylen == namelen) {
-			memcpy(result, sha1, 20);
+			hashcpy(result, sha1);
 			return 0;
 		}
 		if (name[entrylen] != '/')
@@ -187,7 +187,7 @@ static int find_tree_entry(struct tree_desc *t, const char *name, unsigned char
 		if (!S_ISDIR(*mode))
 			break;
 		if (++entrylen == namelen) {
-			memcpy(result, sha1, 20);
+			hashcpy(result, sha1);
 			return 0;
 		}
 		return get_tree_entry(sha1, name + entrylen, result, mode);
diff --git a/tree.c b/tree.c
index ef456be9dd..ea386e5066 100644
--- a/tree.c
+++ b/tree.c
@@ -25,7 +25,7 @@ static int read_one_entry(const unsigned char *sha1, const char *base, int basel
 	ce->ce_flags = create_ce_flags(baselen + len, stage);
 	memcpy(ce->name, base, baselen);
 	memcpy(ce->name + baselen, pathname, len+1);
-	memcpy(ce->sha1, sha1, 20);
+	hashcpy(ce->sha1, sha1);
 	return add_cache_entry(ce, ADD_CACHE_OK_TO_ADD|ADD_CACHE_SKIP_DFCHECK);
 }
 
diff --git a/unpack-trees.c b/unpack-trees.c
index 467d9940f5..3ac0289b3a 100644
--- a/unpack-trees.c
+++ b/unpack-trees.c
@@ -200,7 +200,7 @@ static int unpack_trees_rec(struct tree_entry_list **posns, int len,
 
 			any_files = 1;
 
-			memcpy(ce->sha1, posns[i]->sha1, 20);
+			hashcpy(ce->sha1, posns[i]->sha1);
 			src[i + o->merge] = ce;
 			subposns[i] = df_conflict_list;
 			posns[i] = posns[i]->next;
diff --git a/upload-pack.c b/upload-pack.c
index fcf279843a..51ce936b06 100644
--- a/upload-pack.c
+++ b/upload-pack.c
@@ -374,7 +374,7 @@ static int get_common_commits(void)
 					     sha1_to_hex(sha1),
 					     multi_ack ?  " continue" : "");
 				if (multi_ack)
-					memcpy(last_sha1, sha1, 20);
+					hashcpy(last_sha1, sha1);
 			}
 			continue;
 		}