ns: Added nsGetApplicationDesiredLanguage.

nx/include/switch/nacp.h

@@ -77,5 +77,6 @@ typedef struct {
 } NacpStruct;
 
 /// Get the NacpLanguageEntry from the input nacp corresponding to the current system language (this may fallback to other languages when needed). Output langentry is NULL if none found / content of entry is empty.
+/// If you're using ns you may want to use \ref nsGetApplicationDesiredLanguage instead.
 Result nacpGetLanguageEntry(NacpStruct* nacp, NacpLanguageEntry** langentry);
 

nx/include/switch/services/ns.h

@@ -280,6 +280,14 @@ Result nsGetContentManagementInterface(Service* srv_out);
  */
 Result nsGetApplicationControlData(NsApplicationControlSource source, u64 application_id, NsApplicationControlData* buffer, size_t size, u64* actual_size);
 
+/**
+ * @brief GetApplicationDesiredLanguage. Selects a \ref NacpLanguageEntry to use from the specified \ref NacpStruct.
+ * @note Uses \ref nsGetReadOnlyApplicationControlDataInterface on [5.1.0+], otherwise IApplicationManagerInterface is used.
+ * @param[in] nacp \ref NacpStruct
+ * @param[out] langentry \ref NacpLanguageEntry
+ */
+Result nsGetApplicationDesiredLanguage(NacpStruct *nacp, NacpLanguageEntry **langentry);
+
 ///@}
 
 ///@name IECommerceInterface

nx/source/services/ns.c

@@ -316,6 +316,49 @@ Result nsGetApplicationControlData(NsApplicationControlSource source, u64 applic
     return rc;
 }
 
+Result nsGetApplicationDesiredLanguage(NacpStruct *nacp, NacpLanguageEntry **langentry) {
+    if (nacp==NULL || langentry==NULL)
+        return MAKERESULT(Module_Libnx, LibnxError_BadInput);
+
+    *langentry = NULL;
+
+    NacpLanguageEntry *entry = NULL;
+    Service srv={0}, *srv_ptr = &srv;
+    Result rc=0;
+    u32 cmd_id = 55;
+    if (hosversionAtLeast(5,1,0)) {
+        rc = nsGetReadOnlyApplicationControlDataInterface(&srv);
+        cmd_id = 1;
+    }
+    else
+        srv_ptr = &g_nsAppManSrv;
+
+    u8 lang_bitmask=0, out=0;
+
+    if (R_SUCCEEDED(rc)) {
+        for (u32 i=0; i<16; i++) {
+            entry = &nacp->lang[i];
+            if (entry->name[0] || entry->author[0]) lang_bitmask |= BIT(i);
+        }
+        if (!lang_bitmask) {
+            *langentry = &nacp->lang[0];
+            return 0;
+        }
+    }
+
+    if (R_SUCCEEDED(rc)) rc = serviceDispatchInOut(srv_ptr, cmd_id, lang_bitmask, out);
+    if (R_SUCCEEDED(rc)) {
+        if (out > 16) out = 0;
+        if (lang_bitmask & BIT(out))
+            *langentry = &nacp->lang[out];
+        else
+            rc = MAKERESULT(Module_Libnx, LibnxError_ShouldNotHappen);
+    }
+
+    serviceClose(&srv);
+    return rc;
+}
+
 // IECommerceInterface
 
 Result nsRequestLinkDevice(AsyncResult *a, AccountUid uid) {