From 46dde9368f75013b2383c24d4c8a11763ac8e31e Mon Sep 17 00:00:00 2001
From: Christian Grothoff <christian@grothoff.org>
Date: Wed, 19 Aug 2020 18:19:00 +0200
Subject: implement i18n lookup logic for #6458

---
 src/json/Makefile.am |  1 +
 src/json/i18n.c      | 95 ++++++++++++++++++++++++++++++++++++++++++++++++++++
 2 files changed, 96 insertions(+)
 create mode 100644 src/json/i18n.c

(limited to 'src/json')

diff --git a/src/json/Makefile.am b/src/json/Makefile.am
index 2910d0773..d7c569d60 100644
--- a/src/json/Makefile.am
+++ b/src/json/Makefile.am
@@ -10,6 +10,7 @@ lib_LTLIBRARIES = \
   libtalerjson.la
 
 libtalerjson_la_SOURCES = \
+  i18n.c \
   json.c \
   json_helper.c \
   json_wire.c
diff --git a/src/json/i18n.c b/src/json/i18n.c
new file mode 100644
index 000000000..b92d63ed1
--- /dev/null
+++ b/src/json/i18n.c
@@ -0,0 +1,95 @@
+/*
+  This file is part of TALER
+  Copyright (C) 2020 Taler Systems SA
+
+  TALER is free software; you can redistribute it and/or modify it under the
+  terms of the GNU General Public License as published by the Free Software
+  Foundation; either version 3, or (at your option) any later version.
+
+  TALER is distributed in the hope that it will be useful, but WITHOUT ANY
+  WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR
+  A PARTICULAR PURPOSE.  See the GNU General Public License for more details.
+
+  You should have received a copy of the GNU General Public License along with
+  TALER; see the file COPYING.  If not, see <http://www.gnu.org/licenses/>
+*/
+/**
+ * @file json/i18n.c
+ * @brief helper functions for i18n in JSON processing
+ * @author Christian Grothoff
+ */
+#include "platform.h"
+#include <gnunet/gnunet_util_lib.h>
+#include "taler_util.h"
+#include "taler_json_lib.h"
+
+
+/**
+ * Extract a string from @a object under the field @a field, but respecting
+ * the Taler i18n rules and the language preferences expressed in @a
+ * language_pattern.
+ *
+ * Basically, the @a object may optionally contain a sub-object
+ * "${field}_i18n" with a map from IETF BCP 47 language tags to a localized
+ * version of the string. If this map exists and contains an entry that
+ * matches the @a language pattern, that object (usually a string) is
+ * returned. If the @a language_pattern does not match any entry, or if the
+ * i18n sub-object does not exist, we simply return @a field of @a object
+ * (also usually a string).
+ *
+ * If @a object does not have a member @a field we return NULL (error).
+ *
+ * @param object the object to extract internationalized
+ *        content from
+ * @param language_pattern a language preferences string
+ *        like "fr-CH, fr;q=0.9, en;q=0.8, *;q=0.1", following
+ *        https://tools.ietf.org/html/rfc7231#section-5.3.1
+ * @param field name of the field to extract
+ * @return NULL on error, otherwise the member from
+ *        @a object. Note that the reference counter is
+ *        NOT incremented.
+ */
+const json_t *
+TALER_JSON_extract_i18n (const json_t *object,
+                         const char *language_pattern,
+                         const char *field)
+{
+  const json_t *ret;
+  json_t *i18n;
+  double quality = -1;
+
+  ret = json_object_get (object,
+                         field);
+  if (NULL == ret)
+    return NULL; /* field MUST exist in object */
+  {
+    char *name;
+
+    GNUNET_asprintf (&name,
+                     "%s_i18n",
+                     field);
+    i18n = json_object_get (object,
+                            name);
+    GNUNET_free (name);
+  }
+  if (NULL == i18n)
+    return ret;
+  {
+    const char *key;
+    json_t *value;
+
+    json_object_foreach (i18n, key, value) {
+      double q = TALER_language_matches (language_pattern,
+                                         key);
+      if (q > quality)
+      {
+        quality = q;
+        ret = value;
+      }
+    }
+  }
+  return ret;
+}
+
+
+/* end of i18n.c */
-- 
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