hashmap: convert sha1hash() to oidhash()

There are no callers left of sha1hash() that do not simply pass the
"hash" member of a "struct object_id". Let's get rid of the outdated
sha1-specific function and provide one that operates on the whole struct
(even though the technique, taking the first few bytes of the hash, will
remain the same).

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

builtin/describe.c

@@ -76,7 +76,7 @@ static int commit_name_neq(const void *unused_cmp_data,
 
 static inline struct commit_name *find_commit_name(const struct object_id *peeled)
 {
-	return hashmap_get_from_hash(&names, sha1hash(peeled->hash), peeled);
+	return hashmap_get_from_hash(&names, oidhash(peeled), peeled);
 }
 
 static int replace_name(struct commit_name *e,
@@ -123,7 +123,7 @@ static void add_to_known_names(const char *path,
 		if (!e) {
 			e = xmalloc(sizeof(struct commit_name));
 			oidcpy(&e->peeled, peeled);
-			hashmap_entry_init(e, sha1hash(peeled->hash));
+			hashmap_entry_init(e, oidhash(peeled));
 			hashmap_add(&names, e);
 			e->path = NULL;
 		}

decorate.c

@@ -8,7 +8,7 @@
 
 static unsigned int hash_obj(const struct object *obj, unsigned int n)
 {
-	return sha1hash(obj->oid.hash) % n;
+	return oidhash(&obj->oid) % n;
 }
 
 static void *insert_decoration(struct decoration *n, const struct object *base, void *decoration)

diffcore-rename.c

@@ -266,7 +266,7 @@ static unsigned int hash_filespec(struct repository *r,
 		hash_object_file(filespec->data, filespec->size, "blob",
 				 &filespec->oid);
 	}
-	return sha1hash(filespec->oid.hash);
+	return oidhash(&filespec->oid);
 }
 
 static int find_identical_files(struct hashmap *srcs,

hashmap.h

@@ -1,6 +1,8 @@
 #ifndef HASHMAP_H
 #define HASHMAP_H
 
+#include "hash.h"
+
 /*
  * Generic implementation of hash-based key-value mappings.
  *
@@ -118,14 +120,14 @@ unsigned int memihash_cont(unsigned int hash_seed, const void *buf, size_t len);
  * the results will be different on big-endian and little-endian
  * platforms, so they should not be stored or transferred over the net.
  */
-static inline unsigned int sha1hash(const unsigned char *sha1)
+static inline unsigned int oidhash(const struct object_id *oid)
 {
 	/*
-	 * Equivalent to 'return *(unsigned int *)sha1;', but safe on
+	 * Equivalent to 'return *(unsigned int *)oid->hash;', but safe on
 	 * platforms that don't support unaligned reads.
 	 */
 	unsigned int hash;
-	memcpy(&hash, sha1, sizeof(hash));
+	memcpy(&hash, oid->hash, sizeof(hash));
 	return hash;
 }
 

khash.h

@@ -326,7 +326,7 @@ static const double __ac_HASH_UPPER = 0.77;
 
 static inline unsigned int oidhash_by_value(struct object_id oid)
 {
-	return sha1hash(oid.hash);
+	return oidhash(&oid);
 }
 
 static inline int oideq_by_value(struct object_id a, struct object_id b)

object.c

@@ -61,7 +61,7 @@ int type_from_string_gently(const char *str, ssize_t len, int gentle)
  */
 static unsigned int hash_obj(const struct object_id *oid, unsigned int n)
 {
-	return sha1hash(oid->hash) & (n - 1);
+	return oidhash(oid) & (n - 1);
 }
 
 /*

pack-objects.c

@@ -11,7 +11,7 @@ static uint32_t locate_object_entry_hash(struct packing_data *pdata,
 {
 	uint32_t i, mask = (pdata->index_size - 1);
 
-	i = sha1hash(oid->hash) & mask;
+	i = oidhash(oid) & mask;
 
 	while (pdata->index[i] > 0) {
 		uint32_t pos = pdata->index[i] - 1;

patch-ids.c

@@ -83,7 +83,7 @@ static int init_patch_id_entry(struct patch_id *patch,
 	if (commit_patch_id(commit, &ids->diffopts, &header_only_patch_id, 1, 0))
 		return -1;
 
-	hashmap_entry_init(patch, sha1hash(header_only_patch_id.hash));
+	hashmap_entry_init(patch, oidhash(&header_only_patch_id));
 	return 0;
 }