295 lines
9.5 KiB
C
295 lines
9.5 KiB
C
/* WirePlumber
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*
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* Copyright © 2023 Collabora Ltd.
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* @author George Kiagiadakis <george.kiagiadakis@collabora.com>
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*
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* SPDX-License-Identifier: MIT
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*/
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#include "json-utils.h"
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#include "error.h"
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#include "log.h"
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#include <pipewire/pipewire.h>
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#include <spa/utils/result.h>
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WP_DEFINE_LOCAL_LOG_TOPIC ("wp-json-utils")
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/*! \defgroup wpjsonutils Json Utilities */
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struct match_rules_cb_data
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{
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WpRuleMatchCallback callback;
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gpointer data;
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GError **error;
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};
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static int
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match_rules_cb (void *data, const char *location, const char *action,
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const char *str, size_t len)
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{
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struct match_rules_cb_data *cb_data = data;
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g_autoptr (WpSpaJson) json = wp_spa_json_new_wrap_stringn (str, len);
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return cb_data->callback (cb_data->data, action, json, cb_data->error) ? 0 : -EPIPE;
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}
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/*!
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* \brief Matches the given properties against a set of rules described in JSON
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* and calls the given callback to perform actions on a successful match.
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*
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* The given JSON should be an array of objects, where each object has a
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* "matches" and an "actions" property. The "matches" value should also be
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* an array of objects, where each object is a set of properties to match.
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* Inside such an object, all properties must match to consider a successful
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* match. However, if multiple objects are provided, only one object needs
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* to match.
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*
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* The "actions" value should be an object where the key is the action name
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* and the value can be any valid JSON. Both the action name and the value are
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* passed as-is on the \a callback.
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*
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* \verbatim
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* [
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* {
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* matches = [
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* # any of the items in matches needs to match, if one does,
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* # actions are emited.
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* {
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* # all keys must match the value. ! negates. ~ starts regex.
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* <key> = <value>
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* ...
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* }
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* ...
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* ]
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* actions = {
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* <action> = <value>
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* ...
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* }
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* }
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* ]
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* \endverbatim
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*
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* \ingroup wpjsonutils
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* \param json a JSON array containing rules in the described format
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* \param match_props (transfer none): the properties to match against the rules
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* \param callback (scope call): a function to call for each action on a successful match
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* \param data (closure callback): data to be passed to \a callback
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* \param error (out)(optional): the error that occurred, if any
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* \returns FALSE if an error occurred, TRUE otherwise
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*/
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gboolean
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wp_json_utils_match_rules (WpSpaJson *json, WpProperties *match_props,
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WpRuleMatchCallback callback, gpointer data, GError ** error)
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{
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g_autoptr (GError) cb_error = NULL;
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struct match_rules_cb_data cb_data = { callback, data, &cb_error };
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int res = pw_conf_match_rules (wp_spa_json_get_data (json),
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wp_spa_json_get_size (json), NULL, wp_properties_peek_dict (match_props),
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match_rules_cb, &cb_data);
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if (res < 0) {
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if (cb_error)
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g_propagate_error (error, g_steal_pointer (&cb_error));
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else
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g_set_error (error, WP_DOMAIN_LIBRARY, WP_LIBRARY_ERROR_OPERATION_FAILED,
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"match rules error: %s", spa_strerror (res));
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return FALSE;
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}
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return TRUE;
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}
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struct update_props_cb_data
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{
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WpProperties *props;
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gint count;
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};
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static gboolean
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update_props_cb (gpointer data, const gchar * action, WpSpaJson * value,
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GError ** error)
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{
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struct update_props_cb_data *cb_data = data;
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if (g_str_equal (action, "update-props"))
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cb_data->count += wp_properties_update_from_json (cb_data->props, value);
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return TRUE;
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}
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/*!
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* \brief Matches the given properties against a set of rules described in JSON
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* and updates the properties if the rule actions include the "update-props"
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* action.
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*
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* \ingroup wpjsonutils
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* \param json a JSON array containing rules in the format accepted by
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* wp_json_utils_match_rules()
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* \param props (transfer none): the properties to match against the rules
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* and also update, acting on the "update-props" action
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* \returns the number of properties that were updated
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*/
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gint
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wp_json_utils_match_rules_update_properties (WpSpaJson *json, WpProperties *props)
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{
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g_autoptr (GError) cb_error = NULL;
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struct update_props_cb_data cb_data = { props, 0 };
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wp_json_utils_match_rules (json, props, update_props_cb, &cb_data, &cb_error);
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if (cb_error)
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wp_notice ("%s", cb_error->message);
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return cb_data.count;
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}
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#define OVERRIDE_SECTION_PREFIX "override."
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static WpSpaJson *
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merge_json_objects (WpSpaJson *a, WpSpaJson *b)
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{
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g_autoptr (WpSpaJsonBuilder) builder = NULL;
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builder = wp_spa_json_builder_new_object ();
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/* Add all properties from 'a' that don't exist in 'b' */
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{
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g_autoptr (WpIterator) it = wp_spa_json_new_iterator (a);
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g_auto (GValue) item = G_VALUE_INIT;
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for (; wp_iterator_next (it, &item); g_value_unset (&item)) {
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g_autoptr (WpSpaJson) key = NULL;
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g_autoptr (WpSpaJson) val = NULL;
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g_autoptr (WpSpaJson) j = NULL;
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g_autofree gchar *str = NULL;
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const gchar *key_str;
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g_autofree gchar *override_key_str = NULL;
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gboolean override;
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key = g_value_dup_boxed (&item);
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key_str = str = wp_spa_json_parse_string (key);
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g_return_val_if_fail (key_str, NULL);
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override = g_str_has_prefix (str, OVERRIDE_SECTION_PREFIX);
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if (override)
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key_str += strlen (OVERRIDE_SECTION_PREFIX);
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override_key_str = g_strdup_printf (OVERRIDE_SECTION_PREFIX "%s", key_str);
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g_value_unset (&item);
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g_return_val_if_fail (wp_iterator_next (it, &item), NULL);
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val = g_value_dup_boxed (&item);
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if (!wp_spa_json_object_get (b, key_str, "J", &j, NULL) &&
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!wp_spa_json_object_get (b, override_key_str, "J", &j, NULL)) {
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wp_spa_json_builder_add_property (builder, key_str);
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wp_spa_json_builder_add_json (builder, val);
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}
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}
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}
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/* Add properties from 'b' that don't exist in 'a'. If a property
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* exists in 'a' and does not have the 'override.' prefix, recursively
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* merge it before adding it. Otherwise override it. */
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{
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g_autoptr (WpIterator) it = wp_spa_json_new_iterator (b);
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g_auto (GValue) item = G_VALUE_INIT;
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for (; wp_iterator_next (it, &item); g_value_unset (&item)) {
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g_autoptr (WpSpaJson) key = NULL;
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g_autoptr (WpSpaJson) val = NULL;
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g_autoptr (WpSpaJson) j = NULL;
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g_autofree gchar *str = NULL;
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const gchar *key_str;
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g_autofree gchar *override_key_str = NULL;
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gboolean override;
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key = g_value_dup_boxed (&item);
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key_str = str = wp_spa_json_parse_string (key);
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g_return_val_if_fail (key_str, NULL);
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override = g_str_has_prefix (str, OVERRIDE_SECTION_PREFIX);
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if (override)
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key_str += strlen (OVERRIDE_SECTION_PREFIX);
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override_key_str = g_strdup_printf (OVERRIDE_SECTION_PREFIX "%s", key_str);
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g_value_unset (&item);
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g_return_val_if_fail (wp_iterator_next (it, &item), NULL);
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val = g_value_dup_boxed (&item);
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if (!override &&
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(wp_spa_json_object_get (a, key_str, "J", &j, NULL) ||
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wp_spa_json_object_get (a, override_key_str, "J", &j, NULL))) {
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g_autoptr (WpSpaJson) merged = wp_json_utils_merge_containers (j, val);
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if (!merged) {
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wp_warning ("skipping merge of %s as JSON values are not compatible",
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key_str);
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continue;
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}
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wp_spa_json_builder_add_property (builder, key_str);
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wp_spa_json_builder_add_json (builder, merged);
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} else {
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wp_spa_json_builder_add_property (builder, key_str);
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wp_spa_json_builder_add_json (builder, val);
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}
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}
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}
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return wp_spa_json_builder_end (builder);
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}
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static WpSpaJson *
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merge_json_arrays (WpSpaJson * a, WpSpaJson * b)
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{
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g_autoptr (WpSpaJsonBuilder) builder = NULL;
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builder = wp_spa_json_builder_new_array ();
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/* Add all elements from 'a' */
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{
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g_autoptr (WpIterator) it = wp_spa_json_new_iterator (a);
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g_auto (GValue) item = G_VALUE_INIT;
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for (; wp_iterator_next (it, &item); g_value_unset (&item)) {
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WpSpaJson *j = g_value_get_boxed (&item);
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wp_spa_json_builder_add_json (builder, j);
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}
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}
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/* Add all elements from 'b' */
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{
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g_autoptr (WpIterator) it = wp_spa_json_new_iterator (b);
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g_auto (GValue) item = G_VALUE_INIT;
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for (; wp_iterator_next (it, &item); g_value_unset (&item)) {
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WpSpaJson *j = g_value_get_boxed (&item);
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wp_spa_json_builder_add_json (builder, j);
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}
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}
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return wp_spa_json_builder_end (builder);
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}
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/*!
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* \brief Merges two JSON containers (objects or arrays) into one.
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*
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* If both \a a and \a b are objects, the result will be a new object
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* containing all properties from both \a a and \a b. If a property exists
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* in both \a a and \a b, the values are recursively merged. If a property
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* exists in both \a a and \a b and the property name starts with the
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* "override." prefix in either of those, the value from the key with the
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* prefix is used.
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*
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* If both \a a and \a b are arrays, the result will be a new array
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* containing all elements from both \a a and \a b.
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*
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* If \a a and \a b are not of the same type, NULL is returned.
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*
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* \ingroup wpjsonutils
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* \param a (transfer none): a JSON container
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* \param b (transfer none): a JSON container
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* \returns a new JSON container containing the merged contents of \a a and \a b
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* or NULL if \a a and \a b are not of the same type
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*/
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WpSpaJson *
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wp_json_utils_merge_containers (WpSpaJson * a, WpSpaJson * b)
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{
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if (wp_spa_json_is_array (a) && wp_spa_json_is_array (b))
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return merge_json_arrays (a, b);
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else if (wp_spa_json_is_object (a) && wp_spa_json_is_object (b))
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return merge_json_objects (a, b);
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return NULL;
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}
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