
The previous naming convention was confusing because it did not make it explicit that the string is not being copied. We had this wrong already in the Lua bindings and thanks to some miracle it hasn't backfired so far (it was using the "wrap" behaviour with a string that doesn't stay alive). In some places we actually need the "copy" behaviour and in some other places we need the "wrap" behaviour, so let's have both variants available.
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 descriped 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 descriped 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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