config: refcount the values map This is mostly groundwork to let us re-use the map in the snapshots.
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diff --git a/src/config_file.c b/src/config_file.c
index e5b5655..c53ec01 100644
--- a/src/config_file.c
+++ b/src/config_file.c
@@ -87,8 +87,15 @@ struct reader {
};
typedef struct {
- git_config_backend parent;
+ git_atomic refcount;
git_strmap *values;
+} refcounted_strmap;
+
+typedef struct {
+ git_config_backend parent;
+ /* mutex to coordinate accessing the values */
+ git_mutex values_mutex;
+ refcounted_strmap *values;
int readonly;
} diskfile_header;
@@ -139,18 +146,6 @@ static void cvar_free(cvar_t *var)
git__free(var);
}
-static int cvar_length(cvar_t *var)
-{
- int length = 0;
-
- while (var) {
- length++;
- var = var->next;
- }
-
- return length;
-}
-
int git_config_file_normalize_section(char *start, char *end)
{
char *scan;
@@ -215,6 +210,58 @@ static void free_vars(git_strmap *values)
git_strmap_free(values);
}
+static void refcounted_strmap_free(refcounted_strmap *map)
+{
+ if (!map)
+ return;
+
+ if (git_atomic_dec(&map->refcount) != 0)
+ return;
+
+ free_vars(map->values);
+ git__free(map);
+}
+
+/**
+ * Take the current values map from the backend and increase its
+ * refcount. This is its own function to make sure we use the mutex to
+ * avoid the map pointer from changing under us.
+ */
+static refcounted_strmap *refcounted_strmap_take(diskfile_header *h)
+{
+ refcounted_strmap *map;
+
+ git_mutex_lock(&h->values_mutex);
+
+ map = h->values;
+ git_atomic_inc(&map->refcount);
+
+ git_mutex_unlock(&h->values_mutex);
+
+ return map;
+}
+
+static int refcounted_strmap_alloc(refcounted_strmap **out)
+{
+ refcounted_strmap *map;
+ int error;
+
+ map = git__calloc(1, sizeof(refcounted_strmap));
+ if (!map) {
+ giterr_set_oom();
+ return -1;
+ }
+
+ git_atomic_set(&map->refcount, 1);
+ if ((error = git_strmap_alloc(&map->values)) < 0) {
+ git__free(map);
+ return error;
+ }
+
+ *out = map;
+ return error;
+}
+
static int config_open(git_config_backend *cfg, git_config_level_t level)
{
int res;
@@ -223,13 +270,14 @@ static int config_open(git_config_backend *cfg, git_config_level_t level)
b->level = level;
- if ((res = git_strmap_alloc(&b->header.values)) < 0)
+ if ((res = refcounted_strmap_alloc(&b->header.values)) < 0)
return res;
+ git_mutex_init(&b->header.values_mutex);
git_array_init(b->readers);
reader = git_array_alloc(b->readers);
if (!reader) {
- git_strmap_free(b->header.values);
+ refcounted_strmap_free(b->header.values);
return -1;
}
memset(reader, 0, sizeof(struct reader));
@@ -245,8 +293,8 @@ static int config_open(git_config_backend *cfg, git_config_level_t level)
if (res == GIT_ENOTFOUND)
return 0;
- if (res < 0 || (res = config_parse(b->header.values, b, reader, level, 0)) < 0) {
- free_vars(b->header.values);
+ if (res < 0 || (res = config_parse(b->header.values->values, b, reader, level, 0)) < 0) {
+ refcounted_strmap_free(b->header.values);
b->header.values = NULL;
}
@@ -259,23 +307,29 @@ static int config_open(git_config_backend *cfg, git_config_level_t level)
/* The meat of the refresh, as we want to use it in different places */
static int config__refresh(git_config_backend *cfg)
{
- git_strmap *values = NULL;
+ refcounted_strmap *values = NULL, *tmp;
diskfile_backend *b = (diskfile_backend *)cfg;
struct reader *reader = NULL;
int error = 0;
- if ((error = git_strmap_alloc(&values)) < 0)
+ if ((error = refcounted_strmap_alloc(&values)) < 0)
goto out;
reader = git_array_get(b->readers, git_array_size(b->readers) - 1);
- if ((error = config_parse(values, b, reader, b->level, 0)) < 0)
+ if ((error = config_parse(values->values, b, reader, b->level, 0)) < 0)
goto out;
- values = git__swap(b->header.values, values);
+ git_mutex_lock(&b->header.values_mutex);
+
+ tmp = b->header.values;
+ b->header.values = values;
+ values = tmp;
+
+ git_mutex_unlock(&b->header.values_mutex);
out:
- free_vars(values);
+ refcounted_strmap_free(values);
git_buf_free(&reader->buffer);
return error;
}
@@ -321,7 +375,7 @@ static void backend_free(git_config_backend *_backend)
git_array_clear(backend->readers);
git__free(backend->file_path);
- free_vars(backend->header.values);
+ refcounted_strmap_free(backend->header.values);
git__free(backend);
}
@@ -338,7 +392,7 @@ static int config_iterator_next(
{
git_config_file_iter *it = (git_config_file_iter *) iter;
diskfile_header *h = (diskfile_header *) it->parent.backend;
- git_strmap *values = h->values;
+ git_strmap *values = h->values->values;
int err = 0;
cvar_t * var;
@@ -397,7 +451,8 @@ static int config_iterator_new(
static int config_set(git_config_backend *cfg, const char *name, const char *value)
{
diskfile_backend *b = (diskfile_backend *)cfg;
- git_strmap *values = b->header.values;
+ refcounted_strmap *map;
+ git_strmap *values;
char *key, *esc_value = NULL;
khiter_t pos;
int rval, ret;
@@ -405,6 +460,9 @@ static int config_set(git_config_backend *cfg, const char *name, const char *val
if ((rval = git_config__normalize_name(name, &key)) < 0)
return rval;
+ map = refcounted_strmap_take(&b->header);
+ values = map->values;
+
/*
* Try to find it in the existing values and update it if it
* only has one value.
@@ -414,17 +472,17 @@ static int config_set(git_config_backend *cfg, const char *name, const char *val
cvar_t *existing = git_strmap_value_at(values, pos);
if (existing->next != NULL) {
- git__free(key);
giterr_set(GITERR_CONFIG, "Multivar incompatible with simple set");
- return -1;
+ ret = -1;
+ goto out;
}
/* don't update if old and new values already match */
if ((!existing->entry->value && !value) ||
(existing->entry->value && value &&
!strcmp(existing->entry->value, value))) {
- git__free(key);
- return 0;
+ ret = 0;
+ goto out;
}
}
@@ -441,6 +499,7 @@ static int config_set(git_config_backend *cfg, const char *name, const char *val
ret = config_refresh(cfg);
out:
+ refcounted_strmap_free(map);
git__free(esc_value);
git__free(key);
return ret;
@@ -452,6 +511,7 @@ out:
static int config_get(git_config_backend *cfg, const char *key, const git_config_entry **out)
{
diskfile_header *h = (diskfile_header *)cfg;
+ refcounted_strmap *map;
git_strmap *values;
khiter_t pos;
cvar_t *var;
@@ -460,17 +520,22 @@ static int config_get(git_config_backend *cfg, const char *key, const git_config
if (!h->readonly && ((error = config_refresh(cfg)) < 0))
return error;
- values = h->values;
+ map = refcounted_strmap_take(h);
+ values = map->values;
+
pos = git_strmap_lookup_index(values, key);
/* no error message; the config system will write one */
- if (!git_strmap_valid_index(values, pos))
+ if (!git_strmap_valid_index(values, pos)) {
+ refcounted_strmap_free(map);
return GIT_ENOTFOUND;
+ }
var = git_strmap_value_at(values, pos);
while (var->next)
var = var->next;
+ refcounted_strmap_free(map);
*out = var->entry;
return 0;
}
@@ -479,7 +544,8 @@ static int config_set_multivar(
git_config_backend *cfg, const char *name, const char *regexp, const char *value)
{
diskfile_backend *b = (diskfile_backend *)cfg;
- git_strmap *values = b->header.values;
+ refcounted_strmap *map;
+ git_strmap *values;
char *key;
regex_t preg;
int result;
@@ -490,20 +556,23 @@ static int config_set_multivar(
if ((result = git_config__normalize_name(name, &key)) < 0)
return result;
+ map = refcounted_strmap_take(&b->header);
+ values = b->header.values->values;
+
pos = git_strmap_lookup_index(values, key);
if (!git_strmap_valid_index(values, pos)) {
/* If we don't have it, behave like a normal set */
result = config_set(cfg, name, value);
+ refcounted_strmap_free(map);
git__free(key);
return result;
}
result = regcomp(&preg, regexp, REG_EXTENDED);
if (result < 0) {
- git__free(key);
giterr_set_regex(&preg, result);
- regfree(&preg);
- return -1;
+ result = -1;
+ goto out;
}
/* If we do have it, set call config_write() and reload */
@@ -513,6 +582,7 @@ static int config_set_multivar(
result = config_refresh(cfg);
out:
+ refcounted_strmap_free(map);
git__free(key);
regfree(&preg);
@@ -523,7 +593,7 @@ static int config_delete(git_config_backend *cfg, const char *name)
{
cvar_t *var;
diskfile_backend *b = (diskfile_backend *)cfg;
- git_strmap *values = b->header.values;
+ refcounted_strmap *map; git_strmap *values;
char *key;
int result;
khiter_t pos;
@@ -531,15 +601,20 @@ static int config_delete(git_config_backend *cfg, const char *name)
if ((result = git_config__normalize_name(name, &key)) < 0)
return result;
+ map = refcounted_strmap_take(&b->header);
+ values = b->header.values->values;
+
pos = git_strmap_lookup_index(values, key);
git__free(key);
if (!git_strmap_valid_index(values, pos)) {
+ refcounted_strmap_free(map);
giterr_set(GITERR_CONFIG, "Could not find key '%s' to delete", name);
return GIT_ENOTFOUND;
}
var = git_strmap_value_at(values, pos);
+ refcounted_strmap_free(map);
if (var->next != NULL) {
giterr_set(GITERR_CONFIG, "Cannot delete multivar with a single delete");
@@ -555,7 +630,8 @@ static int config_delete(git_config_backend *cfg, const char *name)
static int config_delete_multivar(git_config_backend *cfg, const char *name, const char *regexp)
{
diskfile_backend *b = (diskfile_backend *)cfg;
- git_strmap *values = b->header.values;
+ refcounted_strmap *map;
+ git_strmap *values;
char *key;
regex_t preg;
int result;
@@ -564,14 +640,20 @@ static int config_delete_multivar(git_config_backend *cfg, const char *name, con
if ((result = git_config__normalize_name(name, &key)) < 0)
return result;
+ map = refcounted_strmap_take(&b->header);
+ values = b->header.values->values;
+
pos = git_strmap_lookup_index(values, key);
if (!git_strmap_valid_index(values, pos)) {
+ refcounted_strmap_free(map);
git__free(key);
giterr_set(GITERR_CONFIG, "Could not find key '%s' to delete", name);
return GIT_ENOTFOUND;
}
+ refcounted_strmap_free(map);
+
result = regcomp(&preg, regexp, REG_EXTENDED);
if (result < 0) {
giterr_set_regex(&preg, result);
@@ -676,7 +758,7 @@ static void backend_readonly_free(git_config_backend *_backend)
if (backend == NULL)
return;
- free_vars(backend->header.values);
+ refcounted_strmap_free(backend->header.values);
git__free(backend);
}
@@ -702,8 +784,8 @@ static int config_readonly_open(git_config_backend *cfg, git_config_level_t leve
{
diskfile_readonly_backend *b = (diskfile_readonly_backend *) cfg;
diskfile_backend *src = b->snapshot_from;
- git_strmap *src_values = src->header.values;
- git_strmap *values;
+ refcounted_strmap *src_map;
+ git_strmap *src_values, *values;
git_strmap_iter i;
cvar_t *src_var;
int error;
@@ -711,10 +793,12 @@ static int config_readonly_open(git_config_backend *cfg, git_config_level_t leve
/* We're just copying data, don't care about the level */
GIT_UNUSED(level);
- if ((error = git_strmap_alloc(&b->header.values)) < 0)
+ if ((error = refcounted_strmap_alloc(&b->header.values)) < 0)
return error;
- values = b->header.values;
+ src_map = refcounted_strmap_take(&src->header);
+ src_values = src->header.values->values;
+ values = b->header.values->values;
i = git_strmap_begin(src_values);
while ((error = git_strmap_next((void **) &src_var, &i, src_values)) == 0) {
@@ -725,8 +809,11 @@ static int config_readonly_open(git_config_backend *cfg, git_config_level_t leve
var = git__calloc(1, sizeof(cvar_t));
GITERR_CHECK_ALLOC(var);
- if (config_entry_dup(&entry, src_var->entry) < 0)
+ if (config_entry_dup(&entry, src_var->entry) < 0) {
+ refcounted_strmap_free(b->header.values);
+ refcounted_strmap_free(src_map);
return -1;
+ }
var->entry = entry;
@@ -738,6 +825,7 @@ static int config_readonly_open(git_config_backend *cfg, git_config_level_t leve
if (error == GIT_ITEROVER)
error = 0;
+ refcounted_strmap_free(src_map);
return error;
}