Support the QT translation system

Fixes: https://github.com/hughsie/appdata-tools/issues/26

17 files changed, 652 insertions, 380 deletions

diff --git a/client/as-compose.c b/client/as-compose.c
index c84c660..2ad4357 100644
--- a/client/as-compose.c
+++ b/client/as-compose.c
@@ -300,29 +300,6 @@ load_appdata (const gchar *prefix, const gchar *app_name, GError **error)
 }
 
 /**
- * get_gettext_domains:
- **/
-static gchar **
-get_gettext_domains (GPtrArray *translations)
-{
-	guint i;
-	guint cnt = 0;
-	AsTranslation *t;
-	g_auto(GStrv) intl_domains = NULL;
-
-	intl_domains = g_new0 (gchar *, translations->len + 1);
-	for (i = 0; i < translations->len; i++) {
-		t = g_ptr_array_index (translations, i);
-		if (as_translation_get_kind (t) != AS_TRANSLATION_KIND_GETTEXT)
-			continue;
-		intl_domains[cnt++] = g_strdup (as_translation_get_id (t));
-	}
-	if (cnt == 0)
-		return NULL;
-	return g_steal_pointer (&intl_domains);
-}
-
-/**
  * main:
  **/
 int
@@ -419,9 +396,7 @@ main (int argc, char **argv)
 	/* load each application specified */
 	for (i = 1; i < (guint) argc; i++) {
 		const gchar *app_name = argv[i];
-		GPtrArray *translations;
 		g_auto(GStrv) intl_domains = NULL;
-		g_autofree gchar *locale_path = NULL;
 		g_autoptr(AsApp) app_appdata = NULL;
 		g_autoptr(AsApp) app_desktop = NULL;
 
@@ -438,24 +413,16 @@ main (int argc, char **argv)
 		}
 
 		/* set translations */
-		translations = as_app_get_translations (app_appdata);
-		intl_domains = get_gettext_domains (translations);
-		if (intl_domains != NULL) {
-			locale_path = g_build_filename (prefix,
-							"share",
-							"locale",
-							NULL);
-			if (!as_app_gettext_search_path (app_appdata,
-							 locale_path,
-							 intl_domains,
+		if (!as_app_builder_search_translations (app_appdata,
+							 prefix,
 							 25,
+							 AS_APP_BUILDER_FLAG_NONE,
 							 NULL,
 							 &error)) {
-				/* TRANSLATORS: the .mo files could not be parsed */
-				g_print ("%s: %s\n", _("Error parsing translations"),
-					 error->message);
-				return EXIT_FAILURE;
-			}
+			/* TRANSLATORS: the .mo files could not be parsed */
+			g_print ("%s: %s\n", _("Error parsing translations"),
+				 error->message);
+			return EXIT_FAILURE;
 		}
 
 		as_store_add_app (store, app_appdata);
diff --git a/data/tests/Makefile.am b/data/tests/Makefile.am
index 330bfa3..42cd208 100644
--- a/data/tests/Makefile.am
+++ b/data/tests/Makefile.am
@@ -30,8 +30,6 @@ test_files =						\
 	font-1-1.fc21.noarch.rpm			\
 	font-serif-1-1.fc21.noarch.rpm			\
 	intltool.appdata.xml.in				\
-	locale/en_GB/LC_MESSAGES/app.mo			\
-	locale/ru/LC_MESSAGES/app.mo			\
 	origin-icons.tar.gz				\
 	origin.xml					\
 	rpmbuild/app.png				\
@@ -49,6 +47,9 @@ test_files =						\
 	usr/share/applications/test.desktop		\
 	usr/share/icons/hicolor/64x64/apps/test2.png	\
 	usr/share/icons/hicolor/128x128/apps/test3.png	\
+	usr/share/kdeapp/translations/kdeapp_fr.qm	\
+	usr/share/locale/en_GB/LC_MESSAGES/app.mo	\
+	usr/share/locale/ru/LC_MESSAGES/app.mo		\
 	usr/share/pixmaps/test.png			\
 	validate.xml.gz
 
diff --git a/data/tests/kdeapp.cpp b/data/tests/kdeapp.cpp
new file mode 100644
index 0000000..327efe8
--- /dev/null
+++ b/data/tests/kdeapp.cpp
@@ -0,0 +1,4 @@
+// lupdate-qt4 kdeapp.pro && lrelease-qt4 kdeapp.pro
+
+//TRANSLATIONS: comment
+label->setText(QObject::tr("Hello World"))
diff --git a/data/tests/kdeapp.pro b/data/tests/kdeapp.pro
new file mode 100644
index 0000000..3f2f5a4
--- /dev/null
+++ b/data/tests/kdeapp.pro
@@ -0,0 +1,3 @@
+SOURCES         = kdeapp.cpp
+CODECFORSRC     = UTF-8
+TRANSLATIONS    = kdeapp_fr.ts
diff --git a/data/tests/kdeapp_fr.ts b/data/tests/kdeapp_fr.ts
new file mode 100644
index 0000000..02e3874
--- /dev/null
+++ b/data/tests/kdeapp_fr.ts
@@ -0,0 +1,12 @@
+<?xml version="1.0" encoding="utf-8"?>
+<!DOCTYPE TS>
+<TS version="2.0" language="fr_FR">
+<context>
+    <name>QObject</name>
+    <message>
+        <location filename="kdeapp.cpp" line="4"/>
+        <source>Hello World</source>
+        <translation type="unfinished">Bonjour le monde</translation>
+    </message>
+</context>
+</TS>
diff --git a/data/tests/usr/share/kdeapp/translations/kdeapp_fr.qm b/data/tests/usr/share/kdeapp/translations/kdeapp_fr.qm
new file mode 100644
index 0000000..3c6397e
--- /dev/null
+++ b/data/tests/usr/share/kdeapp/translations/kdeapp_fr.qm
diff --git a/data/tests/locale/en_GB/LC_MESSAGES/app.mo b/data/tests/usr/share/locale/en_GB/LC_MESSAGES/app.mo
index 985a1ce..985a1ce 100755
--- a/data/tests/locale/en_GB/LC_MESSAGES/app.mo
+++ b/data/tests/usr/share/locale/en_GB/LC_MESSAGES/app.mo
diff --git a/data/tests/locale/ru/LC_MESSAGES/app.mo b/data/tests/usr/share/locale/ru/LC_MESSAGES/app.mo
index e70e55a..e70e55a 100755
--- a/data/tests/locale/ru/LC_MESSAGES/app.mo
+++ b/data/tests/usr/share/locale/ru/LC_MESSAGES/app.mo
diff --git a/libappstream-builder/plugins/asb-plugin-gettext.c b/libappstream-builder/plugins/asb-plugin-gettext.c
index 1f4d4a7..bb035bc 100644
--- a/libappstream-builder/plugins/asb-plugin-gettext.c
+++ b/libappstream-builder/plugins/asb-plugin-gettext.c
@@ -39,6 +39,7 @@ void
 asb_plugin_add_globs (AsbPlugin *plugin, GPtrArray *globs)
 {
 	asb_plugin_add_glob (globs, "/usr/share/locale/*/LC_MESSAGES/*.mo");
+	asb_plugin_add_glob (globs, "/usr/share/*/translations/*.qm");
 }
 
 /**
@@ -51,20 +52,20 @@ asb_plugin_process_app (AsbPlugin *plugin,
 			const gchar *tmpdir,
 			GError **error)
 {
-	g_autofree gchar *root = NULL;
-	g_auto(GStrv) intl_domains = NULL;
+	g_autofree gchar *prefix = NULL;
+	GPtrArray *translations;
 
-	/* search for .mo files in the prefix */
-	root = g_build_filename (tmpdir, "/usr/share/locale", NULL);
-	if (!g_file_test (root, G_FILE_TEST_EXISTS))
-		return TRUE;
+	/* auto-add this */
+	translations = as_app_get_translations (AS_APP (app));
+	if (translations->len == 0) {
+		g_autoptr(AsTranslation) translation = as_translation_new ();
+		as_translation_set_id (translation, asb_package_get_name (pkg));
+		as_app_add_translation (AS_APP (app), translation);
+	}
 
-	/* generate */
-	intl_domains = g_strsplit (asb_package_get_name (pkg), ",", -1);
-	return as_app_gettext_search_path (AS_APP (app),
-					   root,
-					   intl_domains,
-					   25,
-					   NULL,
-					   error);
+	/* search for .mo files in the prefix */
+	prefix = g_build_filename (tmpdir, "usr", NULL);
+	return as_app_builder_search_translations (AS_APP (app), prefix, 25,
+						   AS_APP_BUILDER_FLAG_USE_FALLBACKS,
+						   NULL, error);
 }
diff --git a/libappstream-glib/Makefile.am b/libappstream-glib/Makefile.am
index 212e180..da43fe8 100644
--- a/libappstream-glib/Makefile.am
+++ b/libappstream-glib/Makefile.am
@@ -69,7 +69,7 @@ libappstream_glib_includedir = $(includedir)/libappstream-glib
 libappstream_glib_include_HEADERS =				\
 	appstream-glib.h					\
 	as-app.h						\
-	as-app-gettext.h					\
+	as-app-builder.h					\
 	as-bundle.h						\
 	as-checksum.h						\
 	as-enums.h						\
@@ -91,7 +91,7 @@ libappstream_glib_include_HEADERS =				\
 libappstream_glib_la_SOURCES =					\
 	as-app.c						\
 	as-app-desktop.c					\
-	as-app-gettext.c					\
+	as-app-builder.c					\
 	as-app-inf.c						\
 	as-app-private.h					\
 	as-app-validate.c					\
diff --git a/libappstream-glib/appstream-glib.h b/libappstream-glib/appstream-glib.h
index c50eb69..26f2bea 100644
--- a/libappstream-glib/appstream-glib.h
+++ b/libappstream-glib/appstream-glib.h
@@ -25,7 +25,7 @@
 #define __APPSTREAM_GLIB_H_INSIDE__
 
 #include <as-app.h>
-#include <as-app-gettext.h>
+#include <as-app-builder.h>
 #include <as-bundle.h>
 #include <as-checksum.h>
 #include <as-enums.h>
diff --git a/libappstream-glib/as-app-builder.c b/libappstream-glib/as-app-builder.c
new file mode 100644
index 0000000..8e0cea3
--- /dev/null
+++ b/libappstream-glib/as-app-builder.c
@@ -0,0 +1,514 @@
+/* -*- Mode: C; tab-width: 8; indent-tabs-mode: t; c-basic-offset: 8 -*-
+ *
+ * Copyright (C) 2015 Richard Hughes <richard@hughsie.com>
+ *
+ * Licensed under the GNU Lesser General Public License Version 2.1
+ *
+ * This library is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation; either
+ * version 2.1 of the License, or (at your option) any later version.
+ *
+ * This library 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
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with this library; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301 USA
+ */
+
+/**
+ * SECTION:as-app-builder
+ * @short_description: Scan the filesystem for installed languages
+ * @include: appstream-glib.h
+ * @stability: Stable
+ *
+ * This object will parse a gettext catalog directory and calculate the
+ * language stats for an application.
+ *
+ * See also: #AsApp
+ */
+
+#include "config.h"
+
+#include <fnmatch.h>
+#include <string.h>
+
+#include "as-app-builder.h"
+
+typedef struct {
+	gchar		*locale;
+	guint		 nstrings;
+	guint		 percentage;
+} AsAppBuilderEntry;
+
+typedef struct {
+	guint		 max_nstrings;
+	GList		*data;
+	GPtrArray	*translations;		/* no ref */
+} AsAppBuilderContext;
+
+/**
+ * as_app_builder_entry_new:
+ **/
+static AsAppBuilderEntry *
+as_app_builder_entry_new (void)
+{
+	AsAppBuilderEntry *entry;
+	entry = g_slice_new0 (AsAppBuilderEntry);
+	return entry;
+}
+
+/**
+ * as_app_builder_entry_free:
+ **/
+static void
+as_app_builder_entry_free (AsAppBuilderEntry *entry)
+{
+	g_free (entry->locale);
+	g_slice_free (AsAppBuilderEntry, entry);
+}
+
+/**
+ * as_app_builder_ctx_new:
+ **/
+static AsAppBuilderContext *
+as_app_builder_ctx_new (void)
+{
+	AsAppBuilderContext *ctx;
+	ctx = g_new0 (AsAppBuilderContext, 1);
+	return ctx;
+}
+
+/**
+ * as_app_builder_ctx_free:
+ **/
+static void
+as_app_builder_ctx_free (AsAppBuilderContext *ctx)
+{
+	g_list_free_full (ctx->data, (GDestroyNotify) as_app_builder_entry_free);
+	g_free (ctx);
+}
+
+typedef struct {
+	guint32		 magic;
+	guint32		 revision;
+	guint32		 nstrings;
+	guint32		 orig_tab_offset;
+	guint32		 trans_tab_offset;
+	guint32		 hash_tab_size;
+	guint32		 hash_tab_offset;
+	guint32		 n_sysdep_segments;
+	guint32		 sysdep_segments_offset;
+	guint32		 n_sysdep_strings;
+	guint32		 orig_sysdep_tab_offset;
+	guint32		 trans_sysdep_tab_offset;
+} AsAppBuilderGettextHeader;
+
+/**
+ * as_app_builder_parse_file_gettext:
+ **/
+static gboolean
+as_app_builder_parse_file_gettext (AsAppBuilderContext *ctx,
+				   const gchar *locale,
+				   const gchar *filename,
+				   GError **error)
+{
+	AsAppBuilderEntry *entry;
+	AsAppBuilderGettextHeader *h;
+	g_autofree gchar *data = NULL;
+	gboolean swapped;
+
+	/* read data, although we only strictly need the header */
+	if (!g_file_get_contents (filename, &data, NULL, error))
+		return FALSE;
+
+	h = (AsAppBuilderGettextHeader *) data;
+	if (h->magic == 0x950412de)
+		swapped = FALSE;
+	else if (h->magic == 0xde120495)
+		swapped = TRUE;
+	else {
+		g_set_error_literal (error,
+				     AS_APP_ERROR,
+				     AS_APP_ERROR_FAILED,
+				     "file is invalid");
+		return FALSE;
+	}
+	entry = as_app_builder_entry_new ();
+	entry->locale = g_strdup (locale);
+	if (swapped)
+		entry->nstrings = GUINT32_SWAP_LE_BE (h->nstrings);
+	else
+		entry->nstrings = h->nstrings;
+	if (entry->nstrings > ctx->max_nstrings)
+		ctx->max_nstrings = entry->nstrings;
+	ctx->data = g_list_prepend (ctx->data, entry);
+	return TRUE;
+}
+
+/**
+ * as_app_builder_search_locale_gettext:
+ **/
+static gboolean
+as_app_builder_search_locale_gettext (AsAppBuilderContext *ctx,
+				      const gchar *locale,
+				      const gchar *messages_path,
+				      AsAppBuilderFlags flags,
+				      GError **error)
+{
+	const gchar *filename;
+	gboolean found_anything = FALSE;
+	guint i;
+	g_autoptr(GDir) dir = NULL;
+	g_autoptr(GPtrArray) mo_paths = NULL;
+
+	/* list files */
+	dir = g_dir_open (messages_path, 0, error);
+	if (dir == NULL)
+		return FALSE;
+
+	/* do a first pass at this, trying to find the prefered .mo */
+	mo_paths = g_ptr_array_new_with_free_func (g_free);
+	while ((filename = g_dir_read_name (dir)) != NULL) {
+		g_autofree gchar *path = NULL;
+		path = g_build_filename (messages_path, filename, NULL);
+		if (!g_file_test (path, G_FILE_TEST_EXISTS))
+			continue;
+		for (i = 0; i < ctx->translations->len; i++) {
+			AsTranslation *t = g_ptr_array_index (ctx->translations, i);
+			g_autofree gchar *fn = NULL;
+			if (as_translation_get_kind (t) != AS_TRANSLATION_KIND_GETTEXT &&
+			    as_translation_get_kind (t) != AS_TRANSLATION_KIND_UNKNOWN)
+				continue;
+			fn = g_strdup_printf ("%s.mo", as_translation_get_id (t));
+			if (g_strcmp0 (filename, fn) == 0) {
+				if (!as_app_builder_parse_file_gettext (ctx,
+									locale,
+									path,
+									error))
+					return FALSE;
+				found_anything = TRUE;
+			}
+		}
+		g_ptr_array_add (mo_paths, g_strdup (path));
+	}
+
+	/* we got data from one or more of the translations */
+	if (found_anything == TRUE)
+		return TRUE;
+
+	/* fall back to parsing *everything*, which might give us more
+	 * language results than is actually true */
+	if (flags & AS_APP_BUILDER_FLAG_USE_FALLBACKS) {
+		for (i = 0; i < mo_paths->len; i++) {
+			filename = g_ptr_array_index (mo_paths, i);
+			if (!as_app_builder_parse_file_gettext (ctx,
+								locale,
+								filename,
+								error))
+				return FALSE;
+		}
+	}
+
+	return TRUE;
+}
+
+typedef enum {
+	AS_APP_TRANSLATION_QM_TAG_END		= 1,
+	/* SourceText16 */
+	AS_APP_TRANSLATION_QM_TAG_TRANSLATION	= 3,
+	/* Context16 */
+	AS_APP_TRANSLATION_QM_TAG_OBSOLETE1	= 5,
+	AS_APP_TRANSLATION_QM_TAG_SOURCE_TEXT	= 6,
+	AS_APP_TRANSLATION_QM_TAG_CONTEXT	= 7,
+	AS_APP_TRANSLATION_QM_TAG_COMMENT	= 8,
+	/* Obsolete2 */
+	AS_APP_TRANSLATION_QM_TAG_LAST
+} AsAppBuilderQmTag;
+
+static guint8
+_read_uint8 (const guint8 *data, guint32 *offset)
+{
+	guint8 tmp;
+	tmp = data[*offset];
+	(*offset) += 1;
+	return tmp;
+}
+
+static guint32
+_read_uint32 (const guint8 *data, guint32 *offset)
+{
+	guint32 tmp = 0;
+	memcpy (&tmp, data + *offset, 4);
+	(*offset) += 4;
+	return GUINT32_FROM_BE (tmp);
+}
+
+/**
+ * as_app_builder_parse_file_qt:
+ **/
+static gboolean
+as_app_builder_parse_file_qt (AsAppBuilderContext *ctx,
+			      const gchar *locale,
+			      const gchar *filename,
+			      GError **error)
+{
+	AsAppBuilderEntry *entry;
+	guint32 addr = 0;
+	guint32 len;
+	guint32 m = 0;
+	guint nstrings = 0;
+	g_autofree guint8 *data = NULL;
+	const guint8 qm_magic[] = {
+		0x3c, 0xb8, 0x64, 0x18, 0xca, 0xef, 0x9c, 0x95,
+		0xcd, 0x21, 0x1c, 0xbf, 0x60, 0xa1, 0xbd, 0xdd
+	};
+
+	/* load file */
+	if (!g_file_get_contents (filename, (gchar **) &data, (gsize *) &len, error))
+		return FALSE;
+
+	/* check header */
+	if (len < sizeof(qm_magic) ||
+	    memcmp (data, qm_magic, sizeof(qm_magic)) != 0) {
+		g_set_error_literal (error,
+				     AS_APP_ERROR,
+				     AS_APP_ERROR_FAILED,
+				     "file is invalid");
+		return FALSE;
+	}
+	m += sizeof(qm_magic);
+
+	/* unknown value 0x42? */
+	_read_uint8 (data, &m);
+
+	/* find offset to data table */
+	addr = _read_uint32 (data, &m);
+	m += addr;
+
+	/* unknown! */
+	_read_uint8 (data, &m);
+	_read_uint32 (data, &m);
+	//g_debug ("seeking to QM @ %x\n", m);
+
+	/* read data */
+	while (m < len) {
+		guint8 tag;
+		guint32 tag_len;
+		//g_debug ("QM @%x", m);
+		tag = _read_uint8(data, &m);
+		switch (tag) {
+		case AS_APP_TRANSLATION_QM_TAG_END:
+			//g_debug ("QM{END}");
+			break;
+		case AS_APP_TRANSLATION_QM_TAG_OBSOLETE1:
+			m += 4;
+			break;
+		case AS_APP_TRANSLATION_QM_TAG_TRANSLATION:
+			tag_len = _read_uint32 (data, &m);
+			if (tag_len < 0xffffffff)
+				m += tag_len;
+			//g_debug ("QM{TRANSLATION} len %i", tag_len);
+			nstrings++;
+			break;
+		case AS_APP_TRANSLATION_QM_TAG_SOURCE_TEXT:
+			tag_len = _read_uint32 (data, &m);
+			m += tag_len;
+			//g_debug ("QM{SOURCE_TEXT} len %i", tag_len);
+			break;
+		case AS_APP_TRANSLATION_QM_TAG_CONTEXT:
+			tag_len = _read_uint32 (data, &m);
+			m += tag_len;
+			//g_debug ("QM{CONTEXT} len %i", tag_len);
+			break;
+		case AS_APP_TRANSLATION_QM_TAG_COMMENT:
+			tag_len = _read_uint32 (data, &m);
+			m += tag_len;
+			//g_debug ("QM{COMMENT} len %i", tag_len);
+			break;
+		default:
+			//g_debug ("QM{unknown} tag kind %i", tag);
+			m = G_MAXUINT32;
+			break;
+		}
+	}
+
+//	g_debug ("for QT locale %s, nstrings=%i", locale, nstrings);
+
+	/* add new entry */
+	entry = as_app_builder_entry_new ();
+	entry->locale = g_strdup (locale);
+	entry->nstrings = nstrings;
+	if (entry->nstrings > ctx->max_nstrings)
+		ctx->max_nstrings = entry->nstrings;
+	ctx->data = g_list_prepend (ctx->data, entry);
+	return TRUE;
+}
+
+/**
+ * as_app_builder_search_translations_qt:
+ **/
+static gboolean
+as_app_builder_search_translations_qt (AsAppBuilderContext *ctx,
+				       const gchar *prefix,
+				       AsAppBuilderFlags flags,
+				       GError **error)
+{
+	guint i;
+
+	/* search for each translation ID */
+	for (i = 0; i < ctx->translations->len; i++) {
+		AsTranslation *t;
+		const gchar *filename;
+		const gchar *install_dir;
+		g_autofree gchar *path = NULL;
+		g_autoptr(GDir) dir = NULL;
+
+		/* FIXME: this path probably has to be specified as an attribute
+		 * in the <translations> tag from the AppData file */
+		t = g_ptr_array_index (ctx->translations, i);
+		install_dir = as_translation_get_id (t);
+		path = g_build_filename (prefix,
+					 "share",
+					 install_dir,
+					 "translations",
+					 NULL);
+		if (!g_file_test (path, G_FILE_TEST_EXISTS))
+			return TRUE;
+		dir = g_dir_open (path, 0, error);
+		if (dir == NULL)
+			return FALSE;
+
+		/* the format is ${prefix}/share/${install_dir}/translations/${id}_${locale}.qm */
+		while ((filename = g_dir_read_name (dir)) != NULL) {
+			g_autofree gchar *fn = NULL;
+			g_autofree gchar *locale = NULL;
+			if (as_translation_get_kind (t) != AS_TRANSLATION_KIND_QT &&
+			    as_translation_get_kind (t) != AS_TRANSLATION_KIND_UNKNOWN)
+				continue;
+			if (!g_str_has_prefix (filename, as_translation_get_id (t)))
+				continue;
+			locale = g_strdup (filename + strlen (as_translation_get_id (t)) + 1);
+			g_strdelimit (locale, ".", '\0');
+			fn = g_build_filename (path, filename, NULL);
+			if (!as_app_builder_parse_file_qt (ctx, locale, fn, error))
+				return FALSE;
+		}
+	}
+
+	return TRUE;
+}
+
+/**
+ * as_app_builder_search_translations_gettext:
+ **/
+static gboolean
+as_app_builder_search_translations_gettext (AsAppBuilderContext *ctx,
+					    const gchar *prefix,
+					    AsAppBuilderFlags flags,
+					    GError **error)
+{
+	const gchar *locale;
+	g_autofree gchar *path = NULL;
+	g_autoptr(GDir) dir = NULL;
+
+	path = g_build_filename (prefix, "share", "locale", NULL);
+	if (!g_file_test (path, G_FILE_TEST_EXISTS))
+		return TRUE;
+	dir = g_dir_open (path, 0, error);
+	if (dir == NULL)
+		return FALSE;
+	while ((locale = g_dir_read_name (dir)) != NULL) {
+		g_autofree gchar *fn = NULL;
+		fn = g_build_filename (path, locale, "LC_MESSAGES", NULL);
+		if (!g_file_test (fn, G_FILE_TEST_EXISTS))
+			continue;
+		if (!as_app_builder_search_locale_gettext (ctx, locale, fn, flags, error))
+			return FALSE;
+	}
+	return TRUE;
+}
+
+/**
+ * as_app_builder_entry_sort_cb:
+ **/
+static gint
+as_app_builder_entry_sort_cb (gconstpointer a, gconstpointer b)
+{
+	return g_strcmp0 (((AsAppBuilderEntry *) a)->locale,
+			  ((AsAppBuilderEntry *) b)->locale);
+}
+
+G_DEFINE_AUTOPTR_CLEANUP_FUNC(AsAppBuilderContext, as_app_builder_ctx_free)
+
+/**
+ * as_app_builder_search_translations:
+ * @app: an #AsApp
+ * @prefix: a prefix to search, e.g. "/usr"
+ * @min_percentage: minimum percentage to add language
+ * @flags: #AsAppBuilderFlags, e.g. %AS_APP_BUILDER_FLAG_USE_FALLBACKS
+ * @cancellable: a #GCancellable or %NULL
+ * @error: a #GError or %NULL
+ *
+ * Searches a prefix for languages, and using a heuristic adds <language>
+ * tags to the specified application.
+ *
+ * If there are no #AsTranslation objects set on the #AsApp then all domains
+ * are matched, which may include more languages than you intended to.
+ *
+ * @min_percentage sets the minimum percentage to add a language tag.
+ * The usual value would be 25% and any language less complete than
+ * this will not be added.
+ *
+ * The purpose of this functionality is to avoid blowing up the size
+ * of the AppStream metadata with a lot of extra data detailing
+ * languages with very few translated strings.
+ *
+ * Returns: %TRUE for success
+ *
+ * Since: 0.5.8
+ **/
+gboolean
+as_app_builder_search_translations (AsApp *app,
+				    const gchar *prefix,
+				    guint min_percentage,
+				    AsAppBuilderFlags flags,
+				    GCancellable *cancellable,
+				    GError **error)
+{
+	AsAppBuilderEntry *e;
+	GList *l;
+	g_autoptr(AsAppBuilderContext) ctx = NULL;
+
+	ctx = as_app_builder_ctx_new ();
+	ctx->translations = as_app_get_translations (app);
+
+	/* search for QT .qm files */
+	if (!as_app_builder_search_translations_qt (ctx, prefix, flags, error))
+		return FALSE;
+
+	/* search for gettext .mo files */
+	if (!as_app_builder_search_translations_gettext (ctx, prefix, flags, error))
+		return FALSE;
+
+	/* calculate percentages */
+	for (l = ctx->data; l != NULL; l = l->next) {
+		e = l->data;
+		e->percentage = MIN (e->nstrings * 100 / ctx->max_nstrings, 100);
+	}
+
+	/* sort */
+	ctx->data = g_list_sort (ctx->data, as_app_builder_entry_sort_cb);
+
+	/* add results */
+	for (l = ctx->data; l != NULL; l = l->next) {
+		e = l->data;
+		if (e->percentage < min_percentage)
+			continue;
+		as_app_add_language (app, e->percentage, e->locale);
+	}
+	return TRUE;
+}
diff --git a/libappstream-glib/as-app-gettext.h b/libappstream-glib/as-app-builder.h
index 432e1be..9d0166f 100644
--- a/libappstream-glib/as-app-gettext.h
+++ b/libappstream-glib/as-app-builder.h
@@ -33,12 +33,26 @@
 
 G_BEGIN_DECLS
 
-gboolean	 as_app_gettext_search_path	(AsApp		*app,
-						 const gchar	*path,
-						 gchar		**intl_domains,
-						 guint		 min_percentage,
-						 GCancellable	*cancellable,
-						 GError		**error);
+/**
+ * AsAppBuilderFlags:
+ * @AS_APP_BUILDER_FLAG_NONE:			No special actions to use
+ * @AS_APP_BUILDER_FLAG_USE_FALLBACKS:		Fall back to guesses where required
+ *
+ * The flags to use when building applications.
+ **/
+typedef enum {
+	AS_APP_BUILDER_FLAG_NONE,
+	AS_APP_BUILDER_FLAG_USE_FALLBACKS	= 1,	/* Since: 0.5.8 */
+	/*< private >*/
+	AS_APP_BUILDER_FLAG_LAST,
+} AsAppBuilderFlags;
+
+gboolean	 as_app_builder_search_translations	(AsApp		*app,
+							 const gchar	*prefix,
+							 guint		 min_percentage,
+							 AsAppBuilderFlags flags,
+							 GCancellable	*cancellable,
+							 GError		**error);
 
 G_END_DECLS
 
diff --git a/libappstream-glib/as-app-gettext.c b/libappstream-glib/as-app-gettext.c
deleted file mode 100644
index 8283bef..0000000
--- a/libappstream-glib/as-app-gettext.c
+++ /dev/null
@@ -1,291 +0,0 @@
-/* -*- Mode: C; tab-width: 8; indent-tabs-mode: t; c-basic-offset: 8 -*-
- *
- * Copyright (C) 2015 Richard Hughes <richard@hughsie.com>
- *
- * Licensed under the GNU Lesser General Public License Version 2.1
- *
- * This library is free software; you can redistribute it and/or
- * modify it under the terms of the GNU Lesser General Public
- * License as published by the Free Software Foundation; either
- * version 2.1 of the License, or (at your option) any later version.
- *
- * This library 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
- * Lesser General Public License for more details.
- *
- * You should have received a copy of the GNU Lesser General Public
- * License along with this library; if not, write to the Free Software
- * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301 USA
- */
-
-/**
- * SECTION:as-gettext
- * @short_description: a hashed array gettext of applications
- * @include: appstream-glib.h
- * @stability: Stable
- *
- * This object will parse a gettext catalog directory and calculate the
- * language stats for an application.
- *
- * See also: #AsApp
- */
-
-#include "config.h"
-
-#include <fnmatch.h>
-
-#include "as-app-gettext.h"
-
-typedef struct {
-} AsGettextPrivate;
-
-typedef struct {
-	guint32		 magic;
-	guint32		 revision;
-	guint32		 nstrings;
-	guint32		 orig_tab_offset;
-	guint32		 trans_tab_offset;
-	guint32		 hash_tab_size;
-	guint32		 hash_tab_offset;
-	guint32		 n_sysdep_segments;
-	guint32		 sysdep_segments_offset;
-	guint32		 n_sysdep_strings;
-	guint32		 orig_sysdep_tab_offset;
-	guint32		 trans_sysdep_tab_offset;
-} AsGettextHeader;
-
-typedef struct {
-	gchar		*locale;
-	guint		 nstrings;
-	guint		 percentage;
-} AsGettextEntry;
-
-typedef struct {
-	guint		 max_nstrings;
-	GList		*data;
-	gchar		**intl_domains;
-	guint		 min_percentage;
-} AsGettextContext;
-
-/**
- * as_gettext_entry_new:
- **/
-static AsGettextEntry *
-as_gettext_entry_new (void)
-{
-	AsGettextEntry *entry;
-	entry = g_slice_new0 (AsGettextEntry);
-	return entry;
-}
-
-/**
- * as_gettext_entry_free:
- **/
-static void
-as_gettext_entry_free (AsGettextEntry *entry)
-{
-	g_free (entry->locale);
-	g_slice_free (AsGettextEntry, entry);
-}
-
-/**
- * as_gettext_ctx_new:
- **/
-static AsGettextContext *
-as_gettext_ctx_new (void)
-{
-	AsGettextContext *ctx;
-	ctx = g_new0 (AsGettextContext, 1);
-	return ctx;
-}
-
-/**
- * as_gettext_ctx_free:
- **/
-static void
-as_gettext_ctx_free (AsGettextContext *ctx)
-{
-	g_list_free_full (ctx->data, (GDestroyNotify) as_gettext_entry_free);
-	g_strfreev (ctx->intl_domains);
-	g_free (ctx);
-}
-
-/**
- * as_gettext_parse_file:
- **/
-static gboolean
-as_gettext_parse_file (AsGettextContext *ctx,
-			const gchar *locale,
-			const gchar *filename,
-			GError **error)
-{
-	AsGettextEntry *entry;
-	AsGettextHeader *h;
-	g_autofree gchar *data = NULL;
-	gboolean swapped;
-
-	/* read data, although we only strictly need the header */
-	if (!g_file_get_contents (filename, &data, NULL, error))
-		return FALSE;
-
-	h = (AsGettextHeader *) data;
-	if (h->magic == 0x950412de)
-		swapped = FALSE;
-	else if (h->magic == 0xde120495)
-		swapped = TRUE;
-	else
-		return FALSE;
-	entry = as_gettext_entry_new ();
-	entry->locale = g_strdup (locale);
-	if (swapped)
-		entry->nstrings = GUINT32_SWAP_LE_BE (h->nstrings);
-	else
-		entry->nstrings = h->nstrings;
-	if (entry->nstrings > ctx->max_nstrings)
-		ctx->max_nstrings = entry->nstrings;
-	ctx->data = g_list_prepend (ctx->data, entry);
-	return TRUE;
-}
-
-/**
- * as_gettext_ctx_search_locale:
- **/
-static gboolean
-as_gettext_ctx_search_locale (AsGettextContext *ctx,
-			      const gchar *locale,
-			      const gchar *messages_path,
-			      GError **error)
-{
-	const gchar *filename;
-	gboolean found_anything = FALSE;
-	guint i;
-	g_autoptr(GDir) dir = NULL;
-	g_autoptr(GPtrArray) mo_paths = NULL;
-
-	/* list files */
-	dir = g_dir_open (messages_path, 0, error);
-	if (dir == NULL)
-		return FALSE;
-
-	/* do a first pass at this, trying to find the prefered .mo */
-	mo_paths = g_ptr_array_new_with_free_func (g_free);
-	while ((filename = g_dir_read_name (dir)) != NULL) {
-		g_autofree gchar *path = NULL;
-		path = g_build_filename (messages_path, filename, NULL);
-		if (!g_file_test (path, G_FILE_TEST_EXISTS))
-			continue;
-		for (i = 0; ctx->intl_domains != NULL &&
-			    ctx->intl_domains[i] != NULL; i++) {
-			g_autofree gchar *fn = NULL;
-			fn = g_strdup_printf ("%s.mo", ctx->intl_domains[i]);
-			if (g_strcmp0 (filename, fn) == 0) {
-				if (!as_gettext_parse_file (ctx, locale, path, error))
-					return FALSE;
-				found_anything = TRUE;
-			}
-		}
-		g_ptr_array_add (mo_paths, g_strdup (path));
-	}
-
-	/* we got data from one or more of the intl_domains */
-	if (found_anything == TRUE)
-		return TRUE;
-
-	/* fall back to parsing *everything*, which might give us more
-	 * language results than is actually true */
-	for (i = 0; i < mo_paths->len; i++) {
-		filename = g_ptr_array_index (mo_paths, i);
-		if (!as_gettext_parse_file (ctx, locale, filename, error))
-			return FALSE;
-	}
-
-	return TRUE;
-}
-
-/**
- * as_gettext_entry_sort_cb:
- **/
-static gint
-as_gettext_entry_sort_cb (gconstpointer a, gconstpointer b)
-{
-	return g_strcmp0 (((AsGettextEntry *) a)->locale,
-			  ((AsGettextEntry *) b)->locale);
-}
-
-G_DEFINE_AUTOPTR_CLEANUP_FUNC(AsGettextContext, as_gettext_ctx_free)
-
-/**
- * as_app_gettext_search_path:
- * @app: an #AsApp
- * @path: a path to search, e.g. "/usr/share/locale"
- * @intl_domains: (allow-none): gettext domains, e.g. ["gnome-software"]
- * @min_percentage: minimum percentage to add language
- * @cancellable: a #GCancellable or %NULL
- * @error: a #GError or %NULL
- *
- * Searches a gettext catalog path for languages, and using a heuristic
- * adds <language> tags to the specified application.
- *
- * If @intl_domains is not set then all domains are matched, which may
- * include more languages than you intended to.
- *
- * @min_percentage sets the minimum percentage to add a language tag.
- * The usual value would be 25% and any language less complete than
- * this will not be added.
- *
- * The purpose of this functionality is to avoid blowing up the size
- * of the AppStream metadata with a lot of extra data detailing
- * languages with very few translated strings.
- *
- * Returns: %TRUE for success
- *
- * Since: 0.5.6
- **/
-gboolean
-as_app_gettext_search_path (AsApp *app,
-			    const gchar *path,
-			    gchar **intl_domains,
-			    guint min_percentage,
-			    GCancellable *cancellable,
-			    GError **error)
-{
-	AsGettextEntry *e;
-	GList *l;
-	const gchar *filename;
-	g_autoptr(AsGettextContext) ctx = NULL;
-	g_autoptr(GDir) dir = NULL;
-
-	dir = g_dir_open (path, 0, error);
-	if (dir == NULL)
-		return FALSE;
-	ctx = as_gettext_ctx_new ();
-	ctx->min_percentage = min_percentage;
-	ctx->intl_domains = g_strdupv (intl_domains);
-	while ((filename = g_dir_read_name (dir)) != NULL) {
-		g_autofree gchar *fn = NULL;
-		fn = g_build_filename (path, filename, "LC_MESSAGES", NULL);
-		if (g_file_test (fn, G_FILE_TEST_EXISTS)) {
-			if (!as_gettext_ctx_search_locale (ctx, filename, fn, error))
-				return FALSE;
-		}
-	}
-
-	/* calculate percentages */
-	for (l = ctx->data; l != NULL; l = l->next) {
-		e = l->data;
-		e->percentage = MIN (e->nstrings * 100 / ctx->max_nstrings, 100);
-	}
-
-	/* sort */
-	ctx->data = g_list_sort (ctx->data, as_gettext_entry_sort_cb);
-
-	/* add results */
-	for (l = ctx->data; l != NULL; l = l->next) {
-		e = l->data;
-		if (e->percentage < ctx->min_percentage)
-			continue;
-		as_app_add_language (app, e->percentage, e->locale);
-	}
-	return TRUE;
-}
diff --git a/libappstream-glib/as-self-test.c b/libappstream-glib/as-self-test.c
index b79e219..81ccc81 100644
--- a/libappstream-glib/as-self-test.c
+++ b/libappstream-glib/as-self-test.c
@@ -27,7 +27,7 @@
 #include <fnmatch.h>
 
 #include "as-app-private.h"
-#include "as-app-gettext.h"
+#include "as-app-builder.h"
 #include "as-bundle-private.h"
 #include "as-translation-private.h"
 #include "as-checksum-private.h"
@@ -327,25 +327,29 @@ as_test_monitor_file_func (void)
 }
 
 static void
-as_test_app_gettext_func (void)
+as_test_app_builder_gettext_func (void)
 {
 	GError *error = NULL;
 	gboolean ret;
+	guint i;
 	g_autofree gchar *fn = NULL;
 	g_autoptr(AsApp) app = NULL;
 	g_autoptr(GList) list = NULL;
-	g_auto(GStrv) intl_domains = NULL;
+	const gchar *gettext_domains[] = { "app", "notgoingtoexist", NULL };
 
 	app = as_app_new ();
-	fn = as_test_get_filename ("locale");
+	fn = as_test_get_filename ("usr");
 	g_assert (fn != NULL);
-	intl_domains = g_strsplit ("app,notgoingtoexist", ",", -1);
-	ret = as_app_gettext_search_path (app,
-					  fn,
-					  intl_domains,
-					  25,
-					  NULL,
-					  &error);
+	for (i = 0; gettext_domains[i] != NULL; i++) {
+		g_autoptr(AsTranslation) translation = NULL;
+		translation = as_translation_new ();
+		as_translation_set_kind (translation, AS_TRANSLATION_KIND_GETTEXT);
+		as_translation_set_id (translation, gettext_domains[i]);
+		as_app_add_translation (app, translation);
+	}
+	ret = as_app_builder_search_translations (app, fn, 25,
+						  AS_APP_BUILDER_FLAG_NONE,
+						  NULL, &error);
 	g_assert_no_error (error);
 	g_assert (ret);
 
@@ -360,23 +364,19 @@ as_test_app_gettext_func (void)
 }
 
 static void
-as_test_app_gettext_nodomain_func (void)
+as_test_app_builder_gettext_nodomain_func (void)
 {
 	GError *error = NULL;
 	gboolean ret;
 	g_autofree gchar *fn = NULL;
 	g_autoptr(AsApp) app = NULL;
 	g_autoptr(GList) list = NULL;
-	g_auto(GStrv) intl_domains = NULL;
 
 	app = as_app_new ();
-	fn = as_test_get_filename ("locale");
-	ret = as_app_gettext_search_path (app,
-					  fn,
-					  NULL,
-					  50,
-					  NULL,
-					  &error);
+	fn = as_test_get_filename ("usr");
+	ret = as_app_builder_search_translations (app, fn, 50,
+						  AS_APP_BUILDER_FLAG_USE_FALLBACKS,
+						  NULL, &error);
 	g_assert_no_error (error);
 	g_assert (ret);
 
@@ -391,6 +391,42 @@ as_test_app_gettext_nodomain_func (void)
 }
 
 static void
+as_test_app_builder_qt_func (void)
+{
+	GError *error = NULL;
+	gboolean ret;
+	guint i;
+	g_autofree gchar *fn = NULL;
+	g_autoptr(AsApp) app = NULL;
+	g_autoptr(GList) list = NULL;
+	const gchar *gettext_domains[] = { "kdeapp", "notgoingtoexist", NULL };
+
+	app = as_app_new ();
+	fn = as_test_get_filename ("usr");
+	g_assert (fn != NULL);
+	for (i = 0; gettext_domains[i] != NULL; i++) {
+		g_autoptr(AsTranslation) translation = NULL;
+		translation = as_translation_new ();
+		as_translation_set_kind (translation, AS_TRANSLATION_KIND_QT);
+		as_translation_set_id (translation, gettext_domains[i]);
+		as_app_add_translation (app, translation);
+	}
+	ret = as_app_builder_search_translations (app, fn, 25,
+						  AS_APP_BUILDER_FLAG_NONE,
+						  NULL, &error);
+	g_assert_no_error (error);
+	g_assert (ret);
+
+	/* check langs */
+	g_assert_cmpint (as_app_get_language (app, "fr"), ==, 100);
+	g_assert_cmpint (as_app_get_language (app, "en_GB"), ==, -1);
+
+	/* check size */
+	list = as_app_get_languages (app);
+	g_assert_cmpint (g_list_length (list), ==, 1);
+}
+
+static void
 as_test_tag_func (void)
 {
 	guint i;
@@ -4564,8 +4600,9 @@ main (int argc, char **argv)
 	g_test_add_func ("/AppStream/image{alpha}", as_test_image_alpha_func);
 	g_test_add_func ("/AppStream/screenshot", as_test_screenshot_func);
 	g_test_add_func ("/AppStream/app", as_test_app_func);
-	g_test_add_func ("/AppStream/app{gettext}", as_test_app_gettext_func);
-	g_test_add_func ("/AppStream/app{gettext-nodomain}", as_test_app_gettext_nodomain_func);
+	g_test_add_func ("/AppStream/app{builder:gettext}", as_test_app_builder_gettext_func);
+	g_test_add_func ("/AppStream/app{builder:gettext-nodomain}", as_test_app_builder_gettext_nodomain_func);
+	g_test_add_func ("/AppStream/app{builder:qt}", as_test_app_builder_qt_func);
 	g_test_add_func ("/AppStream/app{translated}", as_test_app_translated_func);
 	g_test_add_func ("/AppStream/app{validate-style}", as_test_app_validate_style_func);
 	g_test_add_func ("/AppStream/app{validate-appdata-good}", as_test_app_validate_appdata_good_func);
diff --git a/libappstream-glib/as-translation.c b/libappstream-glib/as-translation.c
index 79a9675..9a19d56 100644
--- a/libappstream-glib/as-translation.c
+++ b/libappstream-glib/as-translation.c
@@ -98,6 +98,8 @@ as_translation_kind_from_string (const gchar *kind)
 {
 	if (g_strcmp0 (kind, "gettext") == 0)
 		return AS_TRANSLATION_KIND_GETTEXT;
+	if (g_strcmp0 (kind, "qt") == 0)
+		return AS_TRANSLATION_KIND_QT;
 	return AS_TRANSLATION_KIND_UNKNOWN;
 }
 
@@ -116,6 +118,8 @@ as_translation_kind_to_string (AsTranslationKind kind)
 {
 	if (kind == AS_TRANSLATION_KIND_GETTEXT)
 		return "gettext";
+	if (kind == AS_TRANSLATION_KIND_QT)
+		return "qt";
 	return NULL;
 }
 
@@ -204,6 +208,10 @@ as_translation_node_insert (AsTranslation *translation, GNode *parent, AsNodeCon
 	AsTranslationPrivate *priv = GET_PRIVATE (translation);
 	GNode *n;
 
+	/* invalid */
+	if (priv->kind == AS_TRANSLATION_KIND_UNKNOWN)
+		return NULL;
+
 	n = as_node_insert (parent, "translation", priv->id,
 			    AS_NODE_INSERT_FLAG_NONE,
 			    "type", as_translation_kind_to_string (priv->kind),
diff --git a/libappstream-glib/as-translation.h b/libappstream-glib/as-translation.h
index e13937f..333f9dc 100644
--- a/libappstream-glib/as-translation.h
+++ b/libappstream-glib/as-translation.h
@@ -51,12 +51,14 @@ struct _AsTranslationClass
  * AsTranslationKind:
  * @AS_TRANSLATION_KIND_UNKNOWN:		Type invalid or not known
  * @AS_TRANSLATION_KIND_GETTEXT:		Gettext translation system
+ * @AS_TRANSLATION_KIND_QT:			QT translation system
  *
  * The translation type.
  **/
 typedef enum {
-	AS_TRANSLATION_KIND_UNKNOWN,
-	AS_TRANSLATION_KIND_GETTEXT,
+	AS_TRANSLATION_KIND_UNKNOWN,		/* Since: 0.5.7 */
+	AS_TRANSLATION_KIND_GETTEXT,		/* Since: 0.5.7 */
+	AS_TRANSLATION_KIND_QT,			/* Since: 0.5.8 */
 	/*< private >*/
 	AS_TRANSLATION_KIND_LAST
 } AsTranslationKind;