conf: add snd_config_make_path() function

Signed-off-by: Jaroslav Kysela <perex@perex.cz>

diff --git a/include/conf.h b/include/conf.h
index 5c70ebcc9a8e910a512b7af5b4a44a964ea8ee7e..9cf39dc0e1c2dc4823f688bd52133a0235d21581 100644 (file)
--- a/include/conf.h
+++ b/include/conf.h
@@ -131,6 +131,8 @@ int snd_config_make_real(snd_config_t **config, const char *key);
 int snd_config_make_string(snd_config_t **config, const char *key);
 int snd_config_make_pointer(snd_config_t **config, const char *key);
 int snd_config_make_compound(snd_config_t **config, const char *key, int join);
+int snd_config_make_path(snd_config_t **config, snd_config_t *root, const char *key,
+                        int join, int override);
 
 int snd_config_imake_integer(snd_config_t **config, const char *key, const long value);
 int snd_config_imake_integer64(snd_config_t **config, const char *key, const long long value);

diff --git a/src/conf.c b/src/conf.c
index 7ebf75773505b9a06b7f53c9e0c88e266e131eaa..f40fe8835c241c28e882216648a5de27b31da83b 100644 (file)
--- a/src/conf.c
+++ b/src/conf.c
@@ -2547,6 +2547,103 @@ int snd_config_make_compound(snd_config_t **config, const char *id,
        return 0;
 }
 
+/**
+ * \brief Creates an empty compound configuration node in the path.
+ * \param[out] config The function puts the handle to the new or
+ *                   existing compound node at the address specified
+ *                   by \a config.
+ * \param[in] root The id of the new node.
+ * \param[in] key The id of the new node.
+ * \param[in] join Join flag.
+ * \param[in] override Override flag.
+ * \return Zero if successful, otherwise a negative error code.
+ *
+ * This function creates a new empty node of type
+ * #SND_CONFIG_TYPE_COMPOUND if the path does not exist. Otherwise,
+ * the node from the current configuration tree is returned without
+ * any modification. The \a join argument is ignored in this case.
+ *
+ * \a join determines how the compound node's id is printed when the
+ * configuration is saved to a text file.  For example, if the join flag
+ * of compound node \c a is zero, the output will look as follows:
+ * \code
+ * a {
+ *     b "hello"
+ *     c 42
+ * }
+ * \endcode
+ * If, however, the join flag of \c a is nonzero, its id will be joined
+ * with its children's ids, like this:
+ * \code
+ * a.b "hello"
+ * a.c 42
+ * \endcode
+ * An \e empty compound node with its join flag set would result in no
+ * output, i.e., after saving and reloading the configuration file, that
+ * compound node would be lost.
+ *
+ * \par Errors:
+ * <dl>
+ * <dt>-ENOMEM<dd>Out of memory.
+ * <dt>-EACCESS<dd>Path exists, but it's not a compound (!override)
+ * </dl>
+ */
+int snd_config_make_path(snd_config_t **config, snd_config_t *root,
+                        const char *key, int join, int override)
+{
+       snd_config_t *n;
+       const char *p;
+       int err;
+
+       while (1) {
+               p = strchr(key, '.');
+               if (p) {
+                       err = _snd_config_search(root, key, p - key, &n);
+                       if (err < 0) {
+                               size_t l = p - key;
+                               char *s = malloc(l + 1);
+                               if (s == NULL)
+                                       return -ENOMEM;
+                               strncpy(s, key, l);
+                               s[l] = '\0';
+                               err = snd_config_make_compound(&n, s, join);
+                               free(s);
+                               if (err < 0)
+                                       return err;
+                               err = snd_config_add(root, n);
+                               if (err < 0)
+                                       return err;
+                       }
+                       root = n;
+                       key = p + 1;
+               } else {
+                       err = _snd_config_search(root, key, -1, config);
+                       if (err == 0) {
+                               if ((*config)->type != SND_CONFIG_TYPE_COMPOUND) {
+                                       if (override) {
+                                               err = snd_config_delete(*config);
+                                               if (err < 0)
+                                                       return err;
+                                               goto __make;
+                                       } else {
+                                               return -EACCES;
+                                       }
+                               }
+                               return 0;
+                       }
+__make:
+                       err = snd_config_make_compound(&n, key, join);
+                       if (err < 0)
+                               return err;
+                       err = snd_config_add(root, n);
+                       if (err < 0)
+                               return err;
+                       *config = n;
+                       return 0;
+               }
+       }
+}
+
 /**
  * \brief Creates an integer configuration node with the given initial value.
  * \param[out] config The function puts the handle to the new node at