Merge branch 'jt/oidmap'

Introduce a new "oidmap" API and rewrite oidset to use it.

* jt/oidmap:
  oidmap: map with OID as key

Makefile

@@ -824,6 +824,7 @@ LIB_OBJS += notes-cache.o
 LIB_OBJS += notes-merge.o
 LIB_OBJS += notes-utils.o
 LIB_OBJS += object.o
+LIB_OBJS += oidmap.o
 LIB_OBJS += oidset.o
 LIB_OBJS += packfile.o
 LIB_OBJS += pack-bitmap.o

fetch-pack.c

@@ -611,7 +611,7 @@ static int tip_oids_contain(struct oidset *tip_oids,
 	 * add to "newlist" between calls, the additions will always be for
 	 * oids that are already in the set.
 	 */
-	if (!tip_oids->map.tablesize) {
+	if (!tip_oids->map.map.tablesize) {
 		add_refs_to_oidset(tip_oids, unmatched);
 		add_refs_to_oidset(tip_oids, newlist);
 	}

oidmap.c

@@ -0,0 +1,51 @@
+#include "cache.h"
+#include "oidmap.h"
+
+static int cmpfn(const void *hashmap_cmp_fn_data,
+		 const void *entry, const void *entry_or_key,
+		 const void *keydata)
+{
+	const struct oidmap_entry *entry_ = entry;
+	if (keydata)
+		return oidcmp(&entry_->oid, (const struct object_id *) keydata);
+	return oidcmp(&entry_->oid,
+		      &((const struct oidmap_entry *) entry_or_key)->oid);
+}
+
+static int hash(const struct object_id *oid)
+{
+	int hash;
+	memcpy(&hash, oid->hash, sizeof(hash));
+	return hash;
+}
+
+void oidmap_init(struct oidmap *map, size_t initial_size)
+{
+	hashmap_init(&map->map, cmpfn, NULL, initial_size);
+}
+
+void oidmap_free(struct oidmap *map, int free_entries)
+{
+	if (!map)
+		return;
+	hashmap_free(&map->map, free_entries);
+}
+
+void *oidmap_get(const struct oidmap *map, const struct object_id *key)
+{
+	return hashmap_get_from_hash(&map->map, hash(key), key);
+}
+
+void *oidmap_remove(struct oidmap *map, const struct object_id *key)
+{
+	struct hashmap_entry entry;
+	hashmap_entry_init(&entry, hash(key));
+	return hashmap_remove(&map->map, &entry, key);
+}
+
+void *oidmap_put(struct oidmap *map, void *entry)
+{
+	struct oidmap_entry *to_put = entry;
+	hashmap_entry_init(&to_put->internal_entry, hash(&to_put->oid));
+	return hashmap_put(&map->map, to_put);
+}

oidmap.h

@@ -0,0 +1,68 @@
+#ifndef OIDMAP_H
+#define OIDMAP_H
+
+#include "hashmap.h"
+
+/*
+ * struct oidmap_entry is a structure representing an entry in the hash table,
+ * which must be used as first member of user data structures.
+ *
+ * Users should set the oid field. oidmap_put() will populate the
+ * internal_entry field.
+ */
+struct oidmap_entry {
+	/* For internal use only */
+	struct hashmap_entry internal_entry;
+
+	struct object_id oid;
+};
+
+struct oidmap {
+	struct hashmap map;
+};
+
+#define OIDMAP_INIT { { NULL } }
+
+/*
+ * Initializes an oidmap structure.
+ *
+ * `map` is the oidmap to initialize.
+ *
+ * If the total number of entries is known in advance, the `initial_size`
+ * parameter may be used to preallocate a sufficiently large table and thus
+ * prevent expensive resizing. If 0, the table is dynamically resized.
+ */
+extern void oidmap_init(struct oidmap *map, size_t initial_size);
+
+/*
+ * Frees an oidmap structure and allocated memory.
+ *
+ * If `free_entries` is true, each oidmap_entry in the map is freed as well
+ * using stdlibs free().
+ */
+extern void oidmap_free(struct oidmap *map, int free_entries);
+
+/*
+ * Returns the oidmap entry for the specified oid, or NULL if not found.
+ */
+extern void *oidmap_get(const struct oidmap *map,
+			const struct object_id *key);
+
+/*
+ * Adds or replaces an oidmap entry.
+ *
+ * ((struct oidmap_entry *) entry)->internal_entry will be populated by this
+ * function.
+ *
+ * Returns the replaced entry, or NULL if not found (i.e. the entry was added).
+ */
+extern void *oidmap_put(struct oidmap *map, void *entry);
+
+/*
+ * Removes an oidmap entry matching the specified oid.
+ *
+ * Returns the removed entry, or NULL if not found.
+ */
+extern void *oidmap_remove(struct oidmap *map, const struct object_id *key);
+
+#endif

oidset.c

@@ -1,50 +1,30 @@
 #include "cache.h"
 #include "oidset.h"
 
-struct oidset_entry {
-	struct hashmap_entry hash;
-	struct object_id oid;
-};
-
-static int oidset_hashcmp(const void *unused_cmp_data,
-			  const void *va, const void *vb,
-			  const void *vkey)
-{
-	const struct oidset_entry *a = va, *b = vb;
-	const struct object_id *key = vkey;
-	return oidcmp(&a->oid, key ? key : &b->oid);
-}
-
 int oidset_contains(const struct oidset *set, const struct object_id *oid)
 {
-	struct hashmap_entry key;
-
-	if (!set->map.cmpfn)
+	if (!set->map.map.tablesize)
 		return 0;
-
-	hashmap_entry_init(&key, sha1hash(oid->hash));
-	return !!hashmap_get(&set->map, &key, oid);
+	return !!oidmap_get(&set->map, oid);
 }
 
 int oidset_insert(struct oidset *set, const struct object_id *oid)
 {
-	struct oidset_entry *entry;
+	struct oidmap_entry *entry;
 
-	if (!set->map.cmpfn)
-		hashmap_init(&set->map, oidset_hashcmp, NULL, 0);
-
-	if (oidset_contains(set, oid))
+	if (!set->map.map.tablesize)
+		oidmap_init(&set->map, 0);
+	else if (oidset_contains(set, oid))
 		return 1;
 
 	entry = xmalloc(sizeof(*entry));
-	hashmap_entry_init(&entry->hash, sha1hash(oid->hash));
 	oidcpy(&entry->oid, oid);
 
-	hashmap_add(&set->map, entry);
+	oidmap_put(&set->map, entry);
 	return 0;
 }
 
 void oidset_clear(struct oidset *set)
 {
-	hashmap_free(&set->map, 1);
+	oidmap_free(&set->map, 1);
 }

oidset.h

@@ -1,6 +1,8 @@
 #ifndef OIDSET_H
 #define OIDSET_H
 
+#include "oidmap.h"
+
 /**
  * This API is similar to sha1-array, in that it maintains a set of object ids
  * in a memory-efficient way. The major differences are:
@@ -17,10 +19,10 @@
  * A single oidset; should be zero-initialized (or use OIDSET_INIT).
  */
 struct oidset {
-	struct hashmap map;
+	struct oidmap map;
 };
 
-#define OIDSET_INIT { { NULL } }
+#define OIDSET_INIT { OIDMAP_INIT }
 
 /**
  * Returns true iff `set` contains `oid`.