userdiff: add and use for_each_userdiff_driver()

Refactor the userdiff_find_by_namelen() function so that a new
for_each_userdiff_driver() API function does most of the work.

This will be useful for the same reason we've got other for_each_*()
API functions as part of various APIs, and will be used in a follow-up
commit.

Signed-off-by: Ævar Arnfjörð Bjarmason <avarab@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

diff --git a/userdiff.c b/userdiff.c
index 978ae6415594bd7c8128beca8167337d956c384e..a667ccaa8c518b5930b5b4a931d4ebca79300af6 100644 (file)
--- a/userdiff.c
+++ b/userdiff.c
@@ -259,20 +259,33 @@ static struct userdiff_driver driver_false = {
        { NULL, 0 }
 };
 
-static struct userdiff_driver *userdiff_find_by_namelen(const char *k, size_t len)
+struct find_by_namelen_data {
+       const char *name;
+       size_t len;
+       struct userdiff_driver *driver;
+};
+
+static int userdiff_find_by_namelen_cb(struct userdiff_driver *driver,
+                                      enum userdiff_driver_type type, void *priv)
 {
-       int i;
-       for (i = 0; i < ndrivers; i++) {
-               struct userdiff_driver *drv = drivers + i;
-               if (!strncmp(drv->name, k, len) && !drv->name[len])
-                       return drv;
-       }
-       for (i = 0; i < ARRAY_SIZE(builtin_drivers); i++) {
-               struct userdiff_driver *drv = builtin_drivers + i;
-               if (!strncmp(drv->name, k, len) && !drv->name[len])
-                       return drv;
+       struct find_by_namelen_data *cb_data = priv;
+
+       if (!strncmp(driver->name, cb_data->name, cb_data->len) &&
+           !driver->name[cb_data->len]) {
+               cb_data->driver = driver;
+               return 1; /* tell the caller to stop iterating */
        }
-       return NULL;
+       return 0;
+}
+
+static struct userdiff_driver *userdiff_find_by_namelen(const char *name, size_t len)
+{
+       struct find_by_namelen_data udcbdata = {
+               .name = name,
+               .len = len,
+       };
+       for_each_userdiff_driver(userdiff_find_by_namelen_cb, &udcbdata);
+       return udcbdata.driver;
 }
 
 static int parse_funcname(struct userdiff_funcname *f, const char *k,
@@ -379,3 +392,36 @@ struct userdiff_driver *userdiff_get_textconv(struct repository *r,
 
        return driver;
 }
+
+static int for_each_userdiff_driver_list(each_userdiff_driver_fn fn,
+                                        enum userdiff_driver_type type, void *cb_data,
+                                        struct userdiff_driver *drv,
+                                        int drv_size)
+{
+       int i;
+       int ret;
+       for (i = 0; i < drv_size; i++) {
+               struct userdiff_driver *item = drv + i;
+               if ((ret = fn(item, type, cb_data)))
+                       return ret;
+       }
+       return 0;
+}
+
+int for_each_userdiff_driver(each_userdiff_driver_fn fn, void *cb_data)
+{
+       int ret;
+
+       ret = for_each_userdiff_driver_list(fn, USERDIFF_DRIVER_TYPE_CUSTOM,
+                                           cb_data, drivers, ndrivers);
+       if (ret)
+               return ret;
+
+       ret = for_each_userdiff_driver_list(fn, USERDIFF_DRIVER_TYPE_BUILTIN,
+                                           cb_data, builtin_drivers,
+                                           ARRAY_SIZE(builtin_drivers));
+       if (ret)
+               return ret;
+
+       return 0;
+}

diff --git a/userdiff.h b/userdiff.h
index 203057e13e508adaaef1394da9fb086284c79733..aee91bc77e6d592021d8597da7fce0123c779a32 100644 (file)
--- a/userdiff.h
+++ b/userdiff.h
@@ -21,6 +21,12 @@ struct userdiff_driver {
        struct notes_cache *textconv_cache;
        int textconv_want_cache;
 };
+enum userdiff_driver_type {
+       USERDIFF_DRIVER_TYPE_BUILTIN = 1<<0,
+       USERDIFF_DRIVER_TYPE_CUSTOM = 1<<1,
+};
+typedef int (*each_userdiff_driver_fn)(struct userdiff_driver *,
+                                      enum userdiff_driver_type, void *);
 
 int userdiff_config(const char *k, const char *v);
 struct userdiff_driver *userdiff_find_by_name(const char *name);
@@ -34,4 +40,11 @@ struct userdiff_driver *userdiff_find_by_path(struct index_state *istate,
 struct userdiff_driver *userdiff_get_textconv(struct repository *r,
                                              struct userdiff_driver *driver);
 
+/*
+ * Iterate over all userdiff drivers. The userdiff_driver_type
+ * argument to each_userdiff_driver_fn indicates their type. Return
+ * non-zero to exit early from the loop.
+ */
+int for_each_userdiff_driver(each_userdiff_driver_fn, void *);
+
 #endif /* USERDIFF */