luci-base: add support for plural translations and contexts in Lua api

 - Introduce a new luci.template.parser.ntranslate() function which
   takes a count, a singular and a plural translation string as well
   as an optional context argument and returns the appropriate,
   language specific plural translation.

 - Introduce an optional translation context argument in the existing
   luci.template.parser.translate() function

 - Support translation contexts in LuCI template directives.
   Translation messages are split on the first unescaped pipe
   character and the reamining string after the pipe is treated
   as context.

Examples:

 - `string.format(p.ntranslate(n, "1 apple", "%d apples"), n)` will
   return an appropriate plural translation for the given amount.

 - `translate("Load", "The system load")` will return an appropiate
   translation for `Load`, using `The system load` as disambiguation
   context (a `msgctxt` directive in *.po files).

 - Likewise `<%:Load|The system load%>` will translate the word
   `Load` while using the remainder of the string as context.

 - To use pipes in translations strings literally, they must be
   escaped: `<%:Use the "\|" character%>` will translate the literal
   string `Use the "|" character`.

Signed-off-by: Jo-Philipp Wich <jo@mein.io>

1 files changed, 18 insertions, 2 deletions

diff --git a/modules/luci-base/src/template_utils.c b/modules/luci-base/src/template_utils.c
index 0411932ce9..8580405e32 100644
--- a/modules/luci-base/src/template_utils.c
+++ b/modules/luci-base/src/template_utils.c
@@ -474,10 +474,26 @@ void luastr_escape(struct template_buffer *out, const char *s, unsigned int l,
 void luastr_translate(struct template_buffer *out, const char *s, unsigned int l,
 					  int escape_xml)
 {
+	int trlen, idlen = l, ctxtlen = 0, esc = 0;
+	const char *p, *msgid = s, *msgctxt = NULL;
 	char *tr;
-	int trlen;
 
-	if (!lmo_translate(s, l, &tr, &trlen))
+	for (p = s; p < s + l; p++) {
+		if (esc) {
+			esc = 0;
+		}
+		else if (*p == '\\') {
+			esc = 1;
+		}
+		else if (*p == '|') {
+			idlen = p - s;
+			msgctxt = p + 1;
+			ctxtlen = s + l - msgctxt;
+			break;
+		}
+	}
+
+	if (!lmo_translate_ctxt(msgid, idlen, msgctxt, ctxtlen, &tr, &trlen))
 		luastr_escape(out, tr, trlen, escape_xml);
 	else
 		luastr_escape(out, s, l, escape_xml);