strmap: enable allocations to come from a mem_pool

For heavy users of strmaps, allowing the keys and entries to be
allocated from a memory pool can provide significant overhead savings.
Add an option to strmap_init_with_options() to specify a memory pool.

Signed-off-by: Elijah Newren <newren@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

diff --git a/strmap.c b/strmap.c
index 3784865745081e51af80231368f547177af5476f..139afb9d4bc03f6a793e8142846ab2f10ff55040 100644 (file)
--- a/strmap.c
+++ b/strmap.c
@@ -1,5 +1,6 @@
 #include "git-compat-util.h"
 #include "strmap.h"
+#include "mem-pool.h"
 
 int cmp_strmap_entry(const void *hashmap_cmp_fn_data,
                     const struct hashmap_entry *entry1,
@@ -24,13 +25,15 @@ static struct strmap_entry *find_strmap_entry(struct strmap *map,
 
 void strmap_init(struct strmap *map)
 {
-       strmap_init_with_options(map, 1);
+       strmap_init_with_options(map, NULL, 1);
 }
 
 void strmap_init_with_options(struct strmap *map,
+                             struct mem_pool *pool,
                              int strdup_strings)
 {
        hashmap_init(&map->map, cmp_strmap_entry, NULL, 0);
+       map->pool = pool;
        map->strdup_strings = strdup_strings;
 }
 
@@ -42,6 +45,10 @@ static void strmap_free_entries_(struct strmap *map, int free_values)
        if (!map)
                return;
 
+       if (!free_values && map->pool)
+               /* Memory other than util is owned by and freed with the pool */
+               return;
+
        /*
         * We need to iterate over the hashmap entries and free
         * e->key and e->value ourselves; hashmap has no API to
@@ -52,9 +59,11 @@ static void strmap_free_entries_(struct strmap *map, int free_values)
        hashmap_for_each_entry(&map->map, &iter, e, ent) {
                if (free_values)
                        free(e->value);
-               if (map->strdup_strings)
-                       free((char*)e->key);
-               free(e);
+               if (!map->pool) {
+                       if (map->strdup_strings)
+                               free((char*)e->key);
+                       free(e);
+               }
        }
 }
 
@@ -77,11 +86,13 @@ static struct strmap_entry *create_entry(struct strmap *map,
        struct strmap_entry *entry;
        const char *key = str;
 
-       entry = xmalloc(sizeof(*entry));
+       entry = map->pool ? mem_pool_alloc(map->pool, sizeof(*entry))
+                         : xmalloc(sizeof(*entry));
        hashmap_entry_init(&entry->ent, strhash(str));
 
        if (map->strdup_strings)
-               key = xstrdup(str);
+               key = map->pool ? mem_pool_strdup(map->pool, str)
+                               : xstrdup(str);
        entry->key = key;
        entry->value = data;
        return entry;
@@ -128,9 +139,11 @@ void strmap_remove(struct strmap *map, const char *str, int free_value)
                return;
        if (free_value)
                free(ret->value);
-       if (map->strdup_strings)
-               free((char*)ret->key);
-       free(ret);
+       if (!map->pool) {
+               if (map->strdup_strings)
+                       free((char*)ret->key);
+               free(ret);
+       }
 }
 
 void strintmap_incr(struct strintmap *map, const char *str, intptr_t amt)

diff --git a/strmap.h b/strmap.h
index c8c4d7c932a37f84e13a9053d9dbc7cafda0f2c8..8745b7ceb1302babbae2c845eba520f155bba312 100644 (file)
--- a/strmap.h
+++ b/strmap.h
@@ -3,8 +3,10 @@
 
 #include "hashmap.h"
 
+struct mem_pool;
 struct strmap {
        struct hashmap map;
+       struct mem_pool *pool;
        unsigned int strdup_strings:1;
 };
 
@@ -37,9 +39,10 @@ void strmap_init(struct strmap *map);
 
 /*
  * Same as strmap_init, but for those who want to control the memory management
- * carefully instead of using the default of strdup_strings=1.
+ * carefully instead of using the default of strdup_strings=1 and pool=NULL.
  */
 void strmap_init_with_options(struct strmap *map,
+                             struct mem_pool *pool,
                              int strdup_strings);
 
 /*
@@ -137,9 +140,10 @@ static inline void strintmap_init(struct strintmap *map, int default_value)
 
 static inline void strintmap_init_with_options(struct strintmap *map,
                                               int default_value,
+                                              struct mem_pool *pool,
                                               int strdup_strings)
 {
-       strmap_init_with_options(&map->map, strdup_strings);
+       strmap_init_with_options(&map->map, pool, strdup_strings);
        map->default_value = default_value;
 }
 
@@ -221,9 +225,10 @@ static inline void strset_init(struct strset *set)
 }
 
 static inline void strset_init_with_options(struct strset *set,
+                                           struct mem_pool *pool,
                                            int strdup_strings)
 {
-       strmap_init_with_options(&set->map, strdup_strings);
+       strmap_init_with_options(&set->map, pool, strdup_strings);
 }
 
 static inline void strset_clear(struct strset *set)