MINOR: dict: Add dictionary new data structure.

This patch adds minimalistic definitions to implement dictionary new data structure
which is an ebtree of ebpt_node structs with strings as keys. Note that this has nothing
to see with real dictionary data structure (maps of keys in association with values).

Makefile

@@ -788,7 +788,7 @@ OBJS = src/proto_http.o src/cfgparse-listen.o src/proto_htx.o src/stream.o    \
        src/xxhash.o src/hpack-enc.o src/h2.o src/freq_ctr.o src/lru.o         \
        src/protocol.o src/arg.o src/hpack-huff.o src/hdr_idx.o src/base64.o   \
        src/hash.o src/mailers.o src/activity.o src/http_msg.o src/version.o   \
-       src/mworker.o src/mworker-prog.o src/debug.o src/wdt.o
+       src/mworker.o src/mworker-prog.o src/debug.o src/wdt.o src/dict.o
 
 EBTREE_OBJS = $(EBTREE_DIR)/ebtree.o $(EBTREE_DIR)/eb32sctree.o \
               $(EBTREE_DIR)/eb32tree.o $(EBTREE_DIR)/eb64tree.o \

include/common/hathreads.h

@@ -547,6 +547,7 @@ enum lock_label {
 	TLSKEYS_REF_LOCK,
 	AUTH_LOCK,
 	LOGSRV_LOCK,
+	DICT_LOCK,
 	OTHER_LOCK,
 	LOCK_LABELS
 };
@@ -663,6 +664,7 @@ static inline const char *lock_label(enum lock_label label)
 	case TLSKEYS_REF_LOCK:     return "TLSKEYS_REF";
 	case AUTH_LOCK:            return "AUTH";
 	case LOGSRV_LOCK:          return "LOGSRV";
+	case DICT_LOCK:            return "DICT";
 	case OTHER_LOCK:           return "OTHER";
 	case LOCK_LABELS:          break; /* keep compiler happy */
 	};

include/proto/dict.h

@@ -0,0 +1,9 @@
+#ifndef _PROTO_DICT_H
+#define _PROTO_DICT_H
+
+#include <types/dict.h>
+
+struct dict *new_dict(const char *name);
+struct dict_entry *dict_insert(struct dict *d, char *str);
+
+#endif  /* _PROTO_DICT_H */

include/types/dict.h

@@ -0,0 +1,18 @@
+#ifndef _TYPES_DICT_H
+#define _TYPES_DICT_H
+
+#include <common/hathreads.h>
+#include <ebpttree.h>
+
+struct dict_entry {
+	struct ebpt_node value;
+	unsigned int refcount;
+};
+
+struct dict {
+	const char *name;
+	struct eb_root values;
+	__decl_hathreads(HA_RWLOCK_T rwlock);
+};
+
+#endif /* _TYPES_DICT_H */

src/dict.c

@@ -0,0 +1,118 @@
+#include <string.h>
+
+#include <proto/dict.h>
+
+#include <eb32tree.h>
+#include <ebistree.h>
+
+struct dict *new_dict(const char *name)
+{
+	struct dict *dict;
+
+	dict = malloc(sizeof *dict);
+	if (!dict)
+		return NULL;
+
+	dict->name     = name;
+	dict->values   = EB_ROOT_UNIQUE;
+	HA_RWLOCK_INIT(&dict->rwlock);
+
+	return dict;
+}
+
+/*
+ * Allocate a new dictionary entry with <s> as string value which is strdup()'ed.
+ * Returns the new allocated entry if succeeded, NULL if not.
+ */
+static struct dict_entry *new_dict_entry(char *s)
+{
+	struct dict_entry *de;
+
+	de = calloc(1, sizeof *de);
+	if (!de)
+		return NULL;
+
+	de->value.key = strdup(s);
+	if (!de->value.key)
+		goto err;
+
+	de->refcount = 1;
+
+	return de;
+
+ err:
+	free(de->value.key);
+	de->value.key = NULL;
+	free(de);
+	return NULL;
+}
+
+/*
+ * Release the memory allocated for <de> dictionary entry.
+ */
+static void free_dict_entry(struct dict_entry *de)
+{
+	de->refcount = 0;
+	free(de->value.key);
+	de->value.key = NULL;
+	free(de);
+}
+
+/*
+ * Simple function to lookup dictionary entries with <s> as value.
+ */
+static struct dict_entry *__dict_lookup(struct dict *d, const char *s)
+{
+	struct dict_entry *de;
+	struct ebpt_node *node;
+
+	de = NULL;
+	node = ebis_lookup(&d->values, s);
+	if (node)
+		de = container_of(node, struct dict_entry, value);
+
+	return de;
+}
+
+/*
+ * Insert <node> node in <root> ebtree, deleting any already existing node with
+ * the same value.
+ */
+static struct ebpt_node *__dict_insert(struct eb_root *root, struct ebpt_node *node)
+{
+	struct ebpt_node *n;
+
+	n = ebis_insert(root, node);
+	if (n != node) {
+		ebpt_delete(n);
+		free_dict_entry(container_of(n, struct dict_entry, value));
+		ebis_insert(root, node);
+	}
+
+	return node;
+}
+
+/*
+ * Insert an entry in <d> dictionary with <s> as value. *
+ */
+struct dict_entry *dict_insert(struct dict *d, char *s)
+{
+	struct dict_entry *de;
+
+	HA_RWLOCK_RDLOCK(DICT_LOCK, &d->rwlock);
+	de = __dict_lookup(d, s);
+	HA_RWLOCK_RDUNLOCK(DICT_LOCK, &d->rwlock);
+	if (de)
+		return de;
+
+	de = new_dict_entry(s);
+	if (!de)
+		return NULL;
+
+	HA_RWLOCK_WRLOCK(DICT_LOCK, &d->rwlock);
+	__dict_insert(&d->values, &de->value);
+	HA_RWLOCK_WRUNLOCK(DICT_LOCK, &d->rwlock);
+
+	return de;
+}
+