[PATCH 4/9] core: Add API to handle multivalued data

["Juan A. Suarez Romero" <jasuarez igalia com>]

Signed-off-by: Juan A. Suarez Romero <jasuarez igalia com>
---
 src/data/grl-data-multi.c |  307 +++++++++++++++++++++++++++++++++++++++++++--
 src/data/grl-data-multi.h |   12 ++-
 2 files changed, 308 insertions(+), 11 deletions(-)

diff --git a/src/data/grl-data-multi.c b/src/data/grl-data-multi.c
index 2047bc7..819e5e7 100644
--- a/src/data/grl-data-multi.c
+++ b/src/data/grl-data-multi.c
@@ -34,6 +34,7 @@
 
 #include "grl-data-multi.h"
 #include "grl-log.h"
+#include "grl-plugin-registry.h"
 
 struct _GrlDataMultiPrivate {
   GHashTable *extended_data;
@@ -44,17 +45,11 @@ static void grl_data_multi_finalize (GObject *object);
 #define GRL_DATA_MULTI_GET_PRIVATE(o)                                   \
   (G_TYPE_INSTANCE_GET_PRIVATE ((o), GRL_TYPE_DATA_MULTI, GrlDataMultiPrivate))
 
-G_DEFINE_TYPE (GrlDataMulti, grl_data_multi, GRL_TYPE_DATA);
+static void free_list_values (GrlKeyID key, GList *values, gpointer user_data);
 
-static void
-free_list_values (GrlKeyID key,
-                  GList *values,
-                  gpointer user_data)
-{
-  g_list_foreach (values, (GFunc) g_object_unref, NULL);
-  g_list_free (values);
-}
+/* ================ GrlDataMulti GObject ================ */
 
+G_DEFINE_TYPE (GrlDataMulti, grl_data_multi, GRL_TYPE_DATA);
 
 static void
 grl_data_multi_class_init (GrlDataMultiClass *klass)
@@ -89,6 +84,17 @@ grl_data_multi_finalize (GObject *object)
   G_OBJECT_CLASS (grl_data_multi_parent_class)->finalize (object);
 }
 
+/* ================ Utitilies ================ */
+
+static void
+free_list_values (GrlKeyID key, GList *values, gpointer user_data)
+{
+  g_list_foreach (values, (GFunc) g_object_unref, NULL);
+  g_list_free (values);
+}
+
+/* ================ API ================ */
+
 /**
  * grl_data_multi_new:
  *
@@ -102,3 +108,286 @@ grl_data_multi_new (void)
   return g_object_new (GRL_TYPE_DATA_MULTI,
 		       NULL);
 }
+
+/**
+ * grl_data_multi_add:
+ * @mdata: a multivalued data
+ * @prop: a set of related properties with their values
+ *
+ * Adds a new set of values.
+ *
+ * All keys in prop must be related among them.
+ *
+ * mdata will take the ownership of prop, so do not modify it.
+ **/
+void
+grl_data_multi_add (GrlDataMulti *mdata,
+                    GrlProperty *prop)
+{
+  GList *key;
+  GList *keys;
+  GList *values;
+  GrlPluginRegistry *registry;
+  const GList *related_keys;
+  guint l;
+
+  g_return_if_fail (GRL_IS_DATA_MULTI (mdata));
+  g_return_if_fail (GRL_IS_PROPERTY (prop));
+
+  keys = grl_data_get_keys (GRL_DATA (prop));
+  if (!keys) {
+    /* Ignore empty properties */
+    GRL_WARNING ("Empty set of values");
+    g_object_unref (prop);
+    return;
+  }
+
+  /* It is assumed that this property only contains values for related properties.
+     Check if it must be inserted in data or in extended_data */
+
+  l = grl_data_multi_length (mdata, keys->data);
+
+  if (l > 0) {
+    /* Add it in extended data */
+    registry = grl_plugin_registry_get_default ();
+    related_keys = grl_plugin_registry_lookup_metadata_relation (registry,
+                                                                 keys->data);
+    while (related_keys) {
+      values = g_hash_table_lookup (mdata->priv->extended_data,
+                                    related_keys->data);
+      values = g_list_append (values, g_object_ref (prop));
+      g_hash_table_insert (mdata->priv->extended_data,
+                           related_keys->data,
+                           values);
+      related_keys = g_list_next (related_keys);
+    }
+    g_list_free (keys);
+  } else {
+    /* Insert it as single valued data */
+    for (key = keys; key; key = g_list_next (key)) {
+      grl_data_set (GRL_DATA (mdata),
+                    key->data,
+                    grl_data_get (GRL_DATA (prop), key->data));
+    }
+    g_list_free (keys);
+  }
+  g_object_unref (prop);
+}
+
+/**
+ * grl_data_multi_length:
+ * @mdata: a multivalued data
+ * @key: a metadata key
+ *
+ * Returns how many values key has in mdata.
+ *
+ * Returns: number of values
+ **/
+guint
+grl_data_multi_length (GrlDataMulti *mdata,
+                       GrlKeyID key)
+{
+  GrlPluginRegistry *registry;
+  const GList *related_keys;
+  gboolean found = FALSE;
+  guint length;
+
+  g_return_val_if_fail (GRL_IS_DATA_MULTI (mdata), 0);
+
+  /* Check first extended data */
+  length = g_list_length (g_hash_table_lookup (mdata->priv->extended_data,
+                                               key));
+  if (length == 0) {
+    /* Check if we can find the information in data */
+    registry = grl_plugin_registry_get_default ();
+    related_keys = grl_plugin_registry_lookup_metadata_relation (registry, key);
+    while (related_keys && !found) {
+      found = grl_data_key_is_known (GRL_DATA (mdata), related_keys->data);
+      related_keys = g_list_next (related_keys);
+    }
+
+    if (found) {
+      return 1;
+    } else {
+      return 0;
+    }
+  } else {
+    return length + 1;
+  }
+}
+
+/**
+ * grl_data_multi_get:
+ * @mdata: a multivalued data
+ * @key: a metadata key
+ * @pos: element to retrieve, starting at 0
+ *
+ * Returns a set containing the values for key and related keys at position specified.
+ *
+ * Returns: a new #GrlProperty. It must be freed with #g_object_unref()
+ **/
+GrlProperty *
+grl_data_multi_get (GrlDataMulti *mdata,
+                    GrlKeyID key,
+                    guint pos)
+{
+  GrlData *collect_from = NULL;
+  GrlPluginRegistry *registry;
+  GrlProperty *prop = NULL;
+  const GList *related_keys;
+  GList *list_el;
+
+  g_return_val_if_fail (GRL_IS_DATA_MULTI (mdata), NULL);
+
+  if (pos == 0) {
+    collect_from = GRL_DATA (mdata);
+  } else {
+    list_el = g_list_nth (g_hash_table_lookup (mdata->priv->extended_data, key), pos - 1);
+    if (list_el) {
+      collect_from = GRL_DATA (list_el->data);
+    } else {
+      GRL_WARNING ("Wrong position %u to get data", pos);
+    }
+  }
+
+  if (collect_from) {
+    registry = grl_plugin_registry_get_default ();
+    related_keys = grl_plugin_registry_lookup_metadata_relation (registry, key);
+    prop = grl_property_new ();
+    while (related_keys) {
+      grl_data_set (GRL_DATA (prop), key, grl_data_get (collect_from, key));
+      related_keys = g_list_next (related_keys);
+    }
+  }
+
+  return prop;
+}
+
+/**
+ * grl_data_multi_remove:
+ * @mdata: a multivalued data
+ * @key: a metadata key
+ * @pos: position of key to be removed, starting at 0
+ *
+ * Removes key and related keys from position in mdata.
+ **/
+void
+grl_data_multi_remove (GrlDataMulti *mdata,
+                       GrlKeyID key,
+                       guint pos)
+{
+  GList *list_values;
+  GList *to_remove;
+  GrlPluginRegistry *registry;
+  GrlProperty *prop_at_1;
+  const GList *rel_key;
+  const GList *related_keys;
+
+  g_return_if_fail (GRL_IS_DATA_MULTI (mdata));
+
+  /* If element to remove is in position 0 (single-data), then we can replace it
+     by value in pos 1 (extended-data) and then remove 1. If element to remove
+     is >0 then we must remove it and shift values the empty position */
+
+  if (pos < 2) {
+    /* For sure related keys will be needed */
+    registry = grl_plugin_registry_get_default ();
+    related_keys = grl_plugin_registry_lookup_metadata_relation (registry, key);
+  }
+
+  if (pos == 0) {
+    prop_at_1 = grl_data_multi_get (mdata, key, 1);
+    if (prop_at_1) {
+      for (rel_key = related_keys; rel_key; rel_key = g_list_next (rel_key)) {
+        grl_data_set (GRL_DATA (mdata),
+                      rel_key->data,
+                      grl_data_get (GRL_DATA (prop_at_1), rel_key->data));
+      }
+      pos = 1;
+    } else {
+      /* There is no multivalues; remove data */
+      for (rel_key = related_keys; rel_key; rel_key = g_list_next (rel_key)) {
+        grl_data_remove (GRL_DATA (mdata), rel_key->data);
+      }
+    }
+  }
+
+  if (pos > 0) {
+    list_values = g_hash_table_lookup (mdata->priv->extended_data, key);
+    to_remove = g_list_nth (list_values, pos - 1);
+    if (!to_remove) {
+      /* Wrong index; ignore */
+      return;
+    }
+
+    g_object_unref (to_remove->data);
+    list_values = g_list_delete_link (list_values, to_remove);
+    if (pos == 1) {
+      /* Removed the head of extended-data; we need to update all related keys
+         to point to the new header */
+      for (rel_key = related_keys; rel_key; rel_key = g_list_next (rel_key)) {
+        g_hash_table_insert (mdata->priv->extended_data,
+                             rel_key->data,
+                             list_values);
+      }
+    }
+  }
+}
+
+/**
+ * grl_data_multi_update:
+ * @mdata: a multivalued data
+ * @prop: a set of related keys
+ * @pos: position to be updated
+ *
+ * Updates the values at position in mdata with values in prop.
+ *
+ * GrlDataMulti will take ownership of prop, so do not free it after invoking
+ * this function.
+ **/
+void
+grl_data_multi_update (GrlDataMulti *mdata,
+                       GrlProperty *prop,
+                       guint pos)
+{
+  GList *keys;
+  GList *list_val;
+  GrlPluginRegistry *registry;
+  const GList *related_keys;
+
+  g_return_if_fail (GRL_IS_DATA_MULTI (mdata));
+  g_return_if_fail (GRL_IS_PROPERTY (prop));
+
+  keys = grl_data_get_keys (GRL_DATA (prop));
+  if (!keys) {
+    GRL_WARNING ("Empty properties");
+    g_object_unref (prop);
+    return;
+  }
+
+  if (pos == 0) {
+    registry = grl_plugin_registry_get_default ();
+    related_keys = grl_plugin_registry_lookup_metadata_relation (registry,
+                                                                 keys->data);
+    while (related_keys) {
+      grl_data_set (GRL_DATA (mdata),
+                    related_keys->data,
+                    grl_data_get (GRL_DATA (prop), related_keys->data));
+      related_keys = g_list_next (related_keys);
+    }
+    g_object_unref (prop);
+  } else {
+    /* Replace the entire element */
+    list_val = g_list_nth (g_hash_table_lookup (mdata->priv->extended_data,
+                                                keys->data),
+                           pos - 1);
+    if (!list_val) {
+      GRL_WARNING ("Wrong position %u when updating", pos);
+      g_object_unref (prop);
+      return;
+    }
+
+    g_object_unref (list_val->data);
+    list_val->data = prop;
+  }
+}
diff --git a/src/data/grl-data-multi.h b/src/data/grl-data-multi.h
index 3e25973..590197e 100644
--- a/src/data/grl-data-multi.h
+++ b/src/data/grl-data-multi.h
@@ -30,9 +30,8 @@
 #define _GRL_DATA_MULTI_H_
 
 #include <grl-data.h>
+#include <grl-property.h>
 #include <glib-object.h>
-/* #include <grl-metadata-key.h> */
-/* #include <grl-definitions.h> */
 
 G_BEGIN_DECLS
 
@@ -94,6 +93,15 @@ GType grl_data_multi_get_type (void) G_GNUC_CONST;
 
 GrlDataMulti *grl_data_multi_new (void);
 
+void grl_data_multi_add (GrlDataMulti *mdata, GrlProperty *prop);
+
+guint grl_data_multi_length (GrlDataMulti *mdata, GrlKeyID key);
+
+GrlProperty *grl_data_multi_get (GrlDataMulti *mdata, GrlKeyID key, guint pos);
+
+void grl_data_multi_remove (GrlDataMulti *mdata, GrlKeyID key, guint pos);
+
+void grl_data_multi_update (GrlDataMulti *mdata, GrlProperty *prop, guint pos);
 G_END_DECLS
 
 #endif /* _GRL_DATA_MULTI_H_ */
-- 
1.7.1