merge(3p/git): Merge git subtree at v2.29.2 r/1890

This also bumps the stable nixpkgs to 20.09 as of 2020-11-21, because
there is some breakage in the git build related to the netrc
credentials helper which someone has taken care of in nixpkgs.

The stable channel is not used for anything other than git, so this
should be fine.

Change-Id: I3575a19dab09e1e9556cf8231d717de9890484fb

1 files changed, 144 insertions, 37 deletions

diff --git a/third_party/git/hashmap.h b/third_party/git/hashmap.h
index 84249115664b..b011b394fefe 100644
--- a/third_party/git/hashmap.h
+++ b/third_party/git/hashmap.h
@@ -13,7 +13,7 @@
  *
  * struct hashmap map;
  * struct long2string {
- *     struct hashmap_entry ent; // must be the first member!
+ *     struct hashmap_entry ent;
  *     long key;
  *     char value[FLEX_ARRAY];   // be careful with allocating on stack!
  * };
@@ -21,12 +21,16 @@
  * #define COMPARE_VALUE 1
  *
  * static int long2string_cmp(const void *hashmap_cmp_fn_data,
- *                            const struct long2string *e1,
- *                            const struct long2string *e2,
+ *                            const struct hashmap_entry *eptr,
+ *                            const struct hashmap_entry *entry_or_key,
  *                            const void *keydata)
  * {
  *     const char *string = keydata;
  *     unsigned flags = *(unsigned *)hashmap_cmp_fn_data;
+ *     const struct long2string *e1, *e2;
+ *
+ *     e1 = container_of(eptr, const struct long2string, ent);
+ *     e2 = container_of(entry_or_key, const struct long2string, ent);
  *
  *     if (flags & COMPARE_VALUE)
  *         return e1->key != e2->key ||
@@ -41,54 +45,58 @@
  *     char value[255], action[32];
  *     unsigned flags = 0;
  *
- *     hashmap_init(&map, (hashmap_cmp_fn) long2string_cmp, &flags, 0);
+ *     hashmap_init(&map, long2string_cmp, &flags, 0);
  *
  *     while (scanf("%s %ld %s", action, &key, value)) {
  *
  *         if (!strcmp("add", action)) {
  *             struct long2string *e;
  *             FLEX_ALLOC_STR(e, value, value);
- *             hashmap_entry_init(e, memhash(&key, sizeof(long)));
+ *             hashmap_entry_init(&e->ent, memhash(&key, sizeof(long)));
  *             e->key = key;
- *             hashmap_add(&map, e);
+ *             hashmap_add(&map, &e->ent);
  *         }
  *
  *         if (!strcmp("print_all_by_key", action)) {
  *             struct long2string k, *e;
- *             hashmap_entry_init(&k, memhash(&key, sizeof(long)));
+ *             hashmap_entry_init(&k.ent, memhash(&key, sizeof(long)));
  *             k.key = key;
  *
  *             flags &= ~COMPARE_VALUE;
- *             e = hashmap_get(&map, &k, NULL);
+ *             e = hashmap_get_entry(&map, &k, ent, NULL);
  *             if (e) {
  *                 printf("first: %ld %s\n", e->key, e->value);
- *                 while ((e = hashmap_get_next(&map, e)))
+ *                 while ((e = hashmap_get_next_entry(&map, e,
+ *                                              struct long2string, ent))) {
  *                     printf("found more: %ld %s\n", e->key, e->value);
+ *                 }
  *             }
  *         }
  *
  *         if (!strcmp("has_exact_match", action)) {
  *             struct long2string *e;
  *             FLEX_ALLOC_STR(e, value, value);
- *             hashmap_entry_init(e, memhash(&key, sizeof(long)));
+ *             hashmap_entry_init(&e->ent, memhash(&key, sizeof(long)));
  *             e->key = key;
  *
  *             flags |= COMPARE_VALUE;
- *             printf("%sfound\n", hashmap_get(&map, e, NULL) ? "" : "not ");
+ *             printf("%sfound\n",
+ *                    hashmap_get(&map, &e->ent, NULL) ? "" : "not ");
  *             free(e);
  *         }
  *
  *         if (!strcmp("has_exact_match_no_heap_alloc", action)) {
  *             struct long2string k;
- *             hashmap_entry_init(&k, memhash(&key, sizeof(long)));
+ *             hashmap_entry_init(&k.ent, memhash(&key, sizeof(long)));
  *             k.key = key;
  *
  *             flags |= COMPARE_VALUE;
- *             printf("%sfound\n", hashmap_get(&map, &k, value) ? "" : "not ");
+ *             printf("%sfound\n",
+ *                    hashmap_get(&map, &k.ent, value) ? "" : "not ");
  *         }
  *
  *         if (!strcmp("end", action)) {
- *             hashmap_free(&map, 1);
+ *             hashmap_free_entries(&map, struct long2string, ent);
  *             break;
  *         }
  *     }
@@ -133,7 +141,7 @@ static inline unsigned int oidhash(const struct object_id *oid)
 
 /*
  * struct hashmap_entry is an opaque structure representing an entry in the
- * hash table, which must be used as first member of user data structures.
+ * hash table.
  * Ideally it should be followed by an int-sized member to prevent unused
  * memory on 64-bit systems due to alignment.
  */
@@ -160,7 +168,7 @@ struct hashmap_entry {
  * argument `keydata`, respectively. Otherwise, `keydata` is NULL.
  *
  * When it is too expensive to allocate a user entry (either because it is
- * large or varialbe sized, such that it is not on the stack), then the
+ * large or variable sized, such that it is not on the stack), then the
  * relevant data to check for equality should be passed via `keydata`.
  * In this case `key` can be a stripped down version of the user key data
  * or even just a hashmap_entry having the correct hash.
@@ -168,7 +176,8 @@ struct hashmap_entry {
  * The `hashmap_cmp_fn_data` entry is the pointer given in the init function.
  */
 typedef int (*hashmap_cmp_fn)(const void *hashmap_cmp_fn_data,
-			      const void *entry, const void *entry_or_key,
+			      const struct hashmap_entry *entry,
+			      const struct hashmap_entry *entry_or_key,
 			      const void *keydata);
 
 /*
@@ -223,13 +232,20 @@ void hashmap_init(struct hashmap *map,
 			 const void *equals_function_data,
 			 size_t initial_size);
 
+/* internal function for freeing hashmap */
+void hashmap_free_(struct hashmap *map, ssize_t offset);
+
 /*
- * Frees a hashmap structure and allocated memory.
- *
- * If `free_entries` is true, each hashmap_entry in the map is freed as well
- * using stdlibs free().
+ * Frees a hashmap structure and allocated memory, leaves entries undisturbed
  */
-void hashmap_free(struct hashmap *map, int free_entries);
+#define hashmap_free(map) hashmap_free_(map, -1)
+
+/*
+ * Frees @map and all entries.  @type is the struct type of the entry
+ * where @member is the hashmap_entry struct used to associate with @map
+ */
+#define hashmap_free_entries(map, type, member) \
+	hashmap_free_(map, offsetof(type, member));
 
 /* hashmap_entry functions */
 
@@ -244,9 +260,9 @@ void hashmap_free(struct hashmap *map, int free_entries);
  * your structure was allocated with xmalloc(), you can just free(3) it,
  * and if it is on stack, you can just let it go out of scope).
  */
-static inline void hashmap_entry_init(void *entry, unsigned int hash)
+static inline void hashmap_entry_init(struct hashmap_entry *e,
+					unsigned int hash)
 {
-	struct hashmap_entry *e = entry;
 	e->hash = hash;
 	e->next = NULL;
 }
@@ -286,8 +302,9 @@ static inline unsigned int hashmap_get_size(struct hashmap *map)
  * If an entry with matching hash code is found, `key` and `keydata` are passed
  * to `hashmap_cmp_fn` to decide whether the entry matches the key.
  */
-void *hashmap_get(const struct hashmap *map, const void *key,
-			 const void *keydata);
+struct hashmap_entry *hashmap_get(const struct hashmap *map,
+				const struct hashmap_entry *key,
+				const void *keydata);
 
 /*
  * Returns the hashmap entry for the specified hash code and key data,
@@ -301,9 +318,10 @@ void *hashmap_get(const struct hashmap *map, const void *key,
  * `entry_or_key` parameter of `hashmap_cmp_fn` points to a hashmap_entry
  * structure that should not be used in the comparison.
  */
-static inline void *hashmap_get_from_hash(const struct hashmap *map,
-					  unsigned int hash,
-					  const void *keydata)
+static inline struct hashmap_entry *hashmap_get_from_hash(
+					const struct hashmap *map,
+					unsigned int hash,
+					const void *keydata)
 {
 	struct hashmap_entry key;
 	hashmap_entry_init(&key, hash);
@@ -318,7 +336,8 @@ static inline void *hashmap_get_from_hash(const struct hashmap *map,
  * `entry` is the hashmap_entry to start the search from, obtained via a previous
  * call to `hashmap_get` or `hashmap_get_next`.
  */
-void *hashmap_get_next(const struct hashmap *map, const void *entry);
+struct hashmap_entry *hashmap_get_next(const struct hashmap *map,
+			const struct hashmap_entry *entry);
 
 /*
  * Adds a hashmap entry. This allows to add duplicate entries (i.e.
@@ -327,7 +346,7 @@ void *hashmap_get_next(const struct hashmap *map, const void *entry);
  * `map` is the hashmap structure.
  * `entry` is the entry to add.
  */
-void hashmap_add(struct hashmap *map, void *entry);
+void hashmap_add(struct hashmap *map, struct hashmap_entry *entry);
 
 /*
  * Adds or replaces a hashmap entry. If the hashmap contains duplicate
@@ -337,7 +356,20 @@ void hashmap_add(struct hashmap *map, void *entry);
  * `entry` is the entry to add or replace.
  * Returns the replaced entry, or NULL if not found (i.e. the entry was added).
  */
-void *hashmap_put(struct hashmap *map, void *entry);
+struct hashmap_entry *hashmap_put(struct hashmap *map,
+				struct hashmap_entry *entry);
+
+/*
+ * Adds or replaces a hashmap entry contained within @keyvar,
+ * where @keyvar is a pointer to a struct containing a
+ * "struct hashmap_entry" @member.
+ *
+ * Returns the replaced pointer which is of the same type as @keyvar,
+ * or NULL if not found.
+ */
+#define hashmap_put_entry(map, keyvar, member) \
+	container_of_or_null_offset(hashmap_put(map, &(keyvar)->member), \
+				OFFSETOF_VAR(keyvar, member))
 
 /*
  * Removes a hashmap entry matching the specified key. If the hashmap contains
@@ -346,8 +378,24 @@ void *hashmap_put(struct hashmap *map, void *entry);
  *
  * Argument explanation is the same as in `hashmap_get`.
  */
-void *hashmap_remove(struct hashmap *map, const void *key,
-		const void *keydata);
+struct hashmap_entry *hashmap_remove(struct hashmap *map,
+					const struct hashmap_entry *key,
+					const void *keydata);
+
+/*
+ * Removes a hashmap entry contained within @keyvar,
+ * where @keyvar is a pointer to a struct containing a
+ * "struct hashmap_entry" @member.
+ *
+ * See `hashmap_get` for an explanation of @keydata
+ *
+ * Returns the replaced pointer which is of the same type as @keyvar,
+ * or NULL if not found.
+ */
+#define hashmap_remove_entry(map, keyvar, member, keydata) \
+	container_of_or_null_offset( \
+			hashmap_remove(map, &(keyvar)->member, keydata), \
+			OFFSETOF_VAR(keyvar, member))
 
 /*
  * Returns the `bucket` an entry is stored in.
@@ -370,10 +418,10 @@ struct hashmap_iter {
 void hashmap_iter_init(struct hashmap *map, struct hashmap_iter *iter);
 
 /* Returns the next hashmap_entry, or NULL if there are no more entries. */
-void *hashmap_iter_next(struct hashmap_iter *iter);
+struct hashmap_entry *hashmap_iter_next(struct hashmap_iter *iter);
 
 /* Initializes the iterator and returns the first entry, if any. */
-static inline void *hashmap_iter_first(struct hashmap *map,
+static inline struct hashmap_entry *hashmap_iter_first(struct hashmap *map,
 		struct hashmap_iter *iter)
 {
 	hashmap_iter_init(map, iter);
@@ -381,6 +429,65 @@ static inline void *hashmap_iter_first(struct hashmap *map,
 }
 
 /*
+ * returns the first entry in @map using @iter, where the entry is of
+ * @type (e.g. "struct foo") and @member is the name of the
+ * "struct hashmap_entry" in @type
+ */
+#define hashmap_iter_first_entry(map, iter, type, member) \
+	container_of_or_null(hashmap_iter_first(map, iter), type, member)
+
+/* internal macro for hashmap_for_each_entry */
+#define hashmap_iter_next_entry_offset(iter, offset) \
+	container_of_or_null_offset(hashmap_iter_next(iter), offset)
+
+/* internal macro for hashmap_for_each_entry */
+#define hashmap_iter_first_entry_offset(map, iter, offset) \
+	container_of_or_null_offset(hashmap_iter_first(map, iter), offset)
+
+/*
+ * iterate through @map using @iter, @var is a pointer to a type
+ * containing a @member which is a "struct hashmap_entry"
+ */
+#define hashmap_for_each_entry(map, iter, var, member) \
+	for (var = NULL, /* for systems without typeof */ \
+	     var = hashmap_iter_first_entry_offset(map, iter, \
+						OFFSETOF_VAR(var, member)); \
+		var; \
+		var = hashmap_iter_next_entry_offset(iter, \
+						OFFSETOF_VAR(var, member)))
+
+/*
+ * returns a pointer of type matching @keyvar, or NULL if nothing found.
+ * @keyvar is a pointer to a struct containing a
+ * "struct hashmap_entry" @member.
+ */
+#define hashmap_get_entry(map, keyvar, member, keydata) \
+	container_of_or_null_offset( \
+				hashmap_get(map, &(keyvar)->member, keydata), \
+				OFFSETOF_VAR(keyvar, member))
+
+#define hashmap_get_entry_from_hash(map, hash, keydata, type, member) \
+	container_of_or_null(hashmap_get_from_hash(map, hash, keydata), \
+				type, member)
+/*
+ * returns the next equal pointer to @var, or NULL if not found.
+ * @var is a pointer of any type containing "struct hashmap_entry"
+ * @member is the name of the "struct hashmap_entry" field
+ */
+#define hashmap_get_next_entry(map, var, member) \
+	container_of_or_null_offset(hashmap_get_next(map, &(var)->member), \
+				OFFSETOF_VAR(var, member))
+
+/*
+ * iterate @map starting from @var, where @var is a pointer of @type
+ * and @member is the name of the "struct hashmap_entry" field in @type
+ */
+#define hashmap_for_each_entry_from(map, var, member) \
+	for (; \
+		var; \
+		var = hashmap_get_next_entry(map, var, member))
+
+/*
  * Disable item counting and automatic rehashing when adding/removing items.
  *
  * Normally, the hashmap keeps track of the number of items in the map
@@ -396,7 +503,7 @@ static inline void hashmap_disable_item_counting(struct hashmap *map)
 }
 
 /*
- * Re-enable item couting when adding/removing items.
+ * Re-enable item counting when adding/removing items.
  * If counting is currently disabled, it will force count them.
  * It WILL NOT automatically rehash them.
  */