From 0e1cabbd82ba43304150037131b2613299a1a647 Mon Sep 17 00:00:00 2001
From: Iwan Timmer <irtimmer@gmail.com>
Date: Sat, 27 May 2017 16:41:52 +0200
Subject: [PATCH] Check display mode before streaming

---
 libgamestream/client.c | 15 ++++++++++++
 libgamestream/client.h |  1 +
 libgamestream/errors.h |  1 +
 libgamestream/xml.c    | 52 ++++++++++++++++++++++++++++++++++++++++++
 libgamestream/xml.h    |  8 +++++++
 src/main.c             |  2 ++
 6 files changed, 79 insertions(+)

diff --git a/libgamestream/client.c b/libgamestream/client.c
index 24ce1d4..79c12f3 100644
--- a/libgamestream/client.c
+++ b/libgamestream/client.c
@@ -232,6 +232,9 @@ static int load_server_status(PSERVER_DATA server) {
     if (xml_search(data->memory, data->size, "GfeVersion", (char**) &server->serverInfo.serverInfoGfeVersion) != GS_OK)
       goto cleanup;
 
+    if (xml_modelist(data->memory, data->size, &server->modes) != GS_OK)
+      goto cleanup;
+
     // These fields are present on all version of GFE that this client supports
     if (!strlen(currentGameText) || !strlen(pairedText) || !strlen(server->serverInfo.serverInfoAppVersion) || !strlen(stateText))
       goto cleanup;
@@ -641,6 +644,18 @@ int gs_start_app(PSERVER_DATA server, STREAM_CONFIGURATION *config, int appId, b
   char* result = NULL;
   char uuid_str[37];
 
+  PDISPLAY_MODE mode = server->modes;
+  bool correct_mode = false;
+  while (mode != NULL) {
+    if (mode->width == config->width && mode->height == config->height && mode->refresh == config->fps)
+      correct_mode = true;
+
+    mode = mode->next;
+  }
+
+  if (!correct_mode)
+    return GS_NOT_SUPPORTED_MODE;
+
   if (config->height >= 2160 && !server->supports4K)
     return GS_NOT_SUPPORTED_4K;
 
diff --git a/libgamestream/client.h b/libgamestream/client.h
index d1b8f69..5591d70 100644
--- a/libgamestream/client.h
+++ b/libgamestream/client.h
@@ -36,6 +36,7 @@ typedef struct _SERVER_DATA {
   int currentGame;
   int serverMajorVersion;
   char* gsVersion;
+  PDISPLAY_MODE modes;
   SERVER_INFORMATION serverInfo;
 } SERVER_DATA, *PSERVER_DATA;
 
diff --git a/libgamestream/errors.h b/libgamestream/errors.h
index 99e3187..f657ae7 100644
--- a/libgamestream/errors.h
+++ b/libgamestream/errors.h
@@ -27,5 +27,6 @@
 #define GS_IO_ERROR -5
 #define GS_NOT_SUPPORTED_4K -6
 #define GS_UNSUPPORTED_VERSION -7
+#define GS_NOT_SUPPORTED_MODE -8
 
 const char* gs_error;
diff --git a/libgamestream/xml.c b/libgamestream/xml.c
index 9efa963..4e5e86e 100644
--- a/libgamestream/xml.c
+++ b/libgamestream/xml.c
@@ -79,6 +79,37 @@ static void XMLCALL _xml_end_applist_element(void *userData, const char *name) {
   }
 }
 
+static void XMLCALL _xml_start_mode_element(void *userData, const char *name, const char **atts) {
+  struct xml_query *search = (struct xml_query*) userData;
+  if (strcmp("DisplayMode", name) == 0) {
+    PDISPLAY_MODE mode = calloc(1, sizeof(DISPLAY_MODE));
+    if (mode != NULL) {
+      mode->next = (PDISPLAY_MODE) search->data;
+      search->data = mode;
+    }
+  } else if (search->data != NULL && (strcmp("Height", name) == 0 || strcmp("Width", name) == 0 || strcmp("RefreshRate", name) == 0)) {
+    search->memory = malloc(1);
+    search->size = 0;
+    search->start = 1;
+  }
+}
+
+static void XMLCALL _xml_end_mode_element(void *userData, const char *name) {
+  struct xml_query *search = (struct xml_query*) userData;
+  if (search->data != NULL && search->start) {
+    PDISPLAY_MODE mode = (PDISPLAY_MODE) search->data;
+    if (strcmp("Width", name) == 0)
+      mode->width = atoi(search->memory);
+    else if (strcmp("Height", name) == 0)
+      mode->height = atoi(search->memory);
+    else if (strcmp("RefreshRate", name) == 0)
+      mode->refresh = atoi(search->memory);
+
+    free(search->memory);
+    search->start = 0;
+  }
+}
+
 static void XMLCALL _xml_write_data(void *userData, const XML_Char *s, int len) {
   struct xml_query *search = (struct xml_query*) userData;
   if (search->start > 0) {
@@ -141,3 +172,24 @@ int xml_applist(char* data, size_t len, PAPP_LIST *app_list) {
 
   return GS_OK;
 }
+
+int xml_modelist(char* data, size_t len, PDISPLAY_MODE *mode_list) {
+  struct xml_query query = {0};
+  query.memory = calloc(1, 1);
+  XML_Parser parser = XML_ParserCreate("UTF-8");
+  XML_SetUserData(parser, &query);
+  XML_SetElementHandler(parser, _xml_start_mode_element, _xml_end_mode_element);
+  XML_SetCharacterDataHandler(parser, _xml_write_data);
+  if (! XML_Parse(parser, data, len, 1)) {
+    int code = XML_GetErrorCode(parser);
+    gs_error = XML_ErrorString(code);
+    XML_ParserFree(parser);
+    return GS_INVALID;
+  }
+
+  XML_ParserFree(parser);
+  *mode_list = (PDISPLAY_MODE) query.data;
+
+  return GS_OK;
+
+}
diff --git a/libgamestream/xml.h b/libgamestream/xml.h
index 99f488c..aee4214 100644
--- a/libgamestream/xml.h
+++ b/libgamestream/xml.h
@@ -26,5 +26,13 @@ typedef struct _APP_LIST {
   struct _APP_LIST *next;
 } APP_LIST, *PAPP_LIST;
 
+typedef struct _DISPLAY_MODE {
+  unsigned int height;
+  unsigned int width;
+  unsigned int refresh;
+  struct _DISPLAY_MODE *next;
+} DISPLAY_MODE, *PDISPLAY_MODE;
+
 int xml_search(char* data, size_t len, char* node, char** result);
 int xml_applist(char* data, size_t len, PAPP_LIST *app_list);
+int xml_modelist(char* data, size_t len, PDISPLAY_MODE *mode_list);
diff --git a/src/main.c b/src/main.c
index 9c45aee..d07d678 100644
--- a/src/main.c
+++ b/src/main.c
@@ -88,6 +88,8 @@ static void stream(PSERVER_DATA server, PCONFIGURATION config, enum platform sys
   if (ret < 0) {
     if (ret == GS_NOT_SUPPORTED_4K)
       fprintf(stderr, "Server doesn't support 4K\n");
+    else if (ret == GS_NOT_SUPPORTED_MODE)
+      fprintf(stderr, "Server doesn't support %dx%d (%d fps)\n", config->stream.width, config->stream.height, config->stream.fps);
     else
       fprintf(stderr, "Errorcode starting app: %d\n", ret);
     exit(-1);