If l_ta_get for "views" or "buffers" fails, throw an error; src/lua_interface.c

Since l_check{view|docpointer} throw errors, the unprotected C functions that
call them will cause a Lua panic if either textadept.views or textadept.buffers
does not exist and Textadept will exit. This makes sense since the two tables
are integral to the application. Therefore instead of checking if either table
exists in those unprotected C functions and handling a failed check safely,
throw an error and exit Textadept anyway because sooner or later one will be
thrown from l_check{view|docpointer}.

1 files changed, 55 insertions, 53 deletions

diff --git a/src/lua_interface.c b/src/lua_interface.c
index 0be9362e..8e0aaf98 100644
--- a/src/lua_interface.c
+++ b/src/lua_interface.c
@@ -43,6 +43,10 @@ LF l_cf_ta_buffer_new(LS *lua),
    l_cf_pm_focus(LS *lua), l_cf_pm_clear(LS *lua), l_cf_pm_activate(LS *lua),
    l_cf_find_focus(LS *lua);
 
+const char
+  *views_dne = "textadept.views doesn't exist or was overridden.",
+  *buffers_dne = "textadept.buffers doesn't exist or was overridden.";
+
 void l_init(int argc, char **argv) {
   lua = lua_open();
   luaL_openlibs(lua);
@@ -112,7 +116,7 @@ static GtkWidget* l_checkview(LS *lua, int narg, const char *errstr=NULL) {
 }
 
 void l_add_scintilla_window(GtkWidget *editor) {
-  if (!l_ta_get(lua, "views")) { lua_pop(lua, 1); return; }
+  if (!l_ta_get(lua, "views")) luaL_error(lua, views_dne);
   lua_newtable(lua);
   lua_pushlightuserdata(lua, const_cast<GtkWidget*>(editor));
   lua_setfield(lua, -2, "widget_pointer");
@@ -127,16 +131,16 @@ void l_add_scintilla_window(GtkWidget *editor) {
 
 void l_remove_scintilla_window(GtkWidget *editor) {
   lua_newtable(lua);
-  if (l_ta_get(lua, "views")) {
-    lua_pushnil(lua);
-    while (lua_next(lua, -2))
-      editor != l_checkview(lua, -1) ? l_append(lua, -4) : lua_pop(lua, 1);
-  } lua_pop(lua, 1); // views
+  if (!l_ta_get(lua, "views")) luaL_error(lua, views_dne);
+  lua_pushnil(lua);
+  while (lua_next(lua, -2))
+    editor != l_checkview(lua, -1) ? l_append(lua, -4) : lua_pop(lua, 1);
+  lua_pop(lua, 1); // views
   l_ta_set(lua, "views");
 }
 
 void l_goto_scintilla_window(GtkWidget *editor, int n, bool absolute) {
-  if (!l_ta_get(lua, "views")) { lua_pop(lua, 1); return; }
+  if (!l_ta_get(lua, "views")) luaL_error(lua, views_dne);
   if (!absolute) {
     unsigned int idx = 1;
     lua_pushnil(lua);
@@ -160,15 +164,15 @@ void l_goto_scintilla_window(GtkWidget *editor, int n, bool absolute) {
 }
 
 void l_set_view_global(GtkWidget *editor) {
-  if (l_ta_get(lua, "views")) {
-    lua_pushnil(lua);
-    while (lua_next(lua, -2))
-      if (editor == l_checkview(lua, -1)) {
-        lua_setglobal(lua, "view"); // value (view table)
-        lua_pop(lua, 1); // key
-        break;
-      } else lua_pop(lua, 1); // value
-  } lua_pop(lua, 1); // views
+  if (!l_ta_get(lua, "views")) luaL_error(lua, views_dne);
+  lua_pushnil(lua);
+  while (lua_next(lua, -2))
+    if (editor == l_checkview(lua, -1)) {
+      lua_setglobal(lua, "view"); // value (view table)
+      lua_pop(lua, 1); // key
+      break;
+    } else lua_pop(lua, 1); // value
+  lua_pop(lua, 1); // views
 }
 
 /** Checks for a buffer and returns the doc_pointer associated with it. */
@@ -185,7 +189,7 @@ static sptr_t l_checkdocpointer(LS *lua, int narg, const char *errstr=NULL) {
 }
 
 int l_add_scintilla_buffer(sptr_t doc) {
-  if (!l_ta_get(lua, "buffers")) { lua_pop(lua, 1); return 1; }
+  if (!l_ta_get(lua, "buffers")) luaL_error(lua, buffers_dne);
   lua_newtable(lua);
   lua_pushnumber(lua, doc); lua_setfield(lua, -2, "doc_pointer");
   lua_pushboolean(lua, false); lua_setfield(lua, -2, "dirty");
@@ -201,27 +205,25 @@ int l_add_scintilla_buffer(sptr_t doc) {
 
 void l_remove_scintilla_buffer(sptr_t doc) {
   // Switch documents for all views that show the current document.
-  if (l_ta_get(lua, "views")) {
-    lua_pushnil(lua);
-    while (lua_next(lua, -2)) {
-      GtkWidget *editor = l_checkview(lua, -1);
-      sptr_t that_doc = SS(SCINTILLA(editor), SCI_GETDOCPOINTER);
-      if (that_doc == doc) l_goto_scintilla_buffer(editor, -1, false);
-      lua_pop(lua, 1); // value
-    }
+  if (!l_ta_get(lua, "views")) luaL_error(lua, views_dne);
+  lua_pushnil(lua);
+  while (lua_next(lua, -2)) {
+    GtkWidget *editor = l_checkview(lua, -1);
+    sptr_t that_doc = SS(SCINTILLA(editor), SCI_GETDOCPOINTER);
+    if (that_doc == doc) l_goto_scintilla_buffer(editor, -1, false);
+    lua_pop(lua, 1); // value
   } lua_pop(lua, 1); // views
-
   lua_newtable(lua);
-  if (l_ta_get(lua, "buffers")) {
-    lua_pushnil(lua);
-    while (lua_next(lua, -2))
-      doc != l_checkdocpointer(lua, -1) ? l_append(lua, -4) : lua_pop(lua, 1);
-  } lua_pop(lua, 1); // buffers
+  if (!l_ta_get(lua, "buffers")) luaL_error(lua, buffers_dne);
+  lua_pushnil(lua);
+  while (lua_next(lua, -2))
+    doc != l_checkdocpointer(lua, -1) ? l_append(lua, -4) : lua_pop(lua, 1);
+  lua_pop(lua, 1); // buffers
   l_ta_set(lua, "buffers");
 }
 
 unsigned int l_get_docpointer_index(sptr_t doc) {
-  if (!l_ta_get(lua, "buffers")) { lua_pop(lua, 1); return 1; }
+  if (!l_ta_get(lua, "buffers")) luaL_error(lua, buffers_dne);
   unsigned int idx = 1;
   lua_pushnil(lua);
   while (lua_next(lua, -2))
@@ -239,7 +241,7 @@ unsigned int l_get_docpointer_index(sptr_t doc) {
 #define l_get_buffer_prop(k, i) { lua_pushstring(lua, k); lua_rawget(lua, i); }
 
 void l_goto_scintilla_buffer(GtkWidget *editor, int n, bool absolute) {
-  if (!l_ta_get(lua, "buffers")) { lua_pop(lua, 1); return; }
+  if (!l_ta_get(lua, "buffers")) luaL_error(lua, buffers_dne);
   ScintillaObject *sci = SCINTILLA(editor);
   if (!absolute) {
     sptr_t doc = SS(sci, SCI_GETDOCPOINTER);
@@ -278,27 +280,26 @@ void l_goto_scintilla_buffer(GtkWidget *editor, int n, bool absolute) {
 
 void l_set_buffer_global(ScintillaObject *sci) {
   sptr_t doc = SS(sci, SCI_GETDOCPOINTER);
-  if (l_ta_get(lua, "buffers")) {
-    lua_pushnil(lua);
-    while (lua_next(lua, -2))
-      if (doc == l_checkdocpointer(lua, -1)) {
-        lua_setglobal(lua, "buffer"); // value (buffer table)
-        lua_pop(lua, 1); // key
-        break;
-      } else lua_pop(lua, 1); // value
-  } lua_pop(lua, 1); // buffers
+  if (!l_ta_get(lua, "buffers")) luaL_error(lua, buffers_dne);
+  lua_pushnil(lua);
+  while (lua_next(lua, -2))
+    if (doc == l_checkdocpointer(lua, -1)) {
+      lua_setglobal(lua, "buffer"); // value (buffer table)
+      lua_pop(lua, 1); // key
+      break;
+    } else lua_pop(lua, 1); // value
+  lua_pop(lua, 1); // buffers
 }
 
 void l_close() {
   closing = true;
   while (unsplit_window(focused_editor));
-  if (l_ta_get(lua, "buffers")) {
-    lua_pushnil(lua);
-    while (lua_next(lua, -2)) {
-      sptr_t doc = l_checkdocpointer(lua, -1);
-      remove_scintilla_buffer(doc);
-      lua_pop(lua, 1); // value
-    }
+  if (!l_ta_get(lua, "buffers")) luaL_error(lua, buffers_dne);
+  lua_pushnil(lua);
+  while (lua_next(lua, -2)) {
+    sptr_t doc = l_checkdocpointer(lua, -1);
+    remove_scintilla_buffer(doc);
+    lua_pop(lua, 1); // value
   } lua_pop(lua, 1); // buffers
   gtk_widget_destroy(focused_editor);
   lua_close(lua);
@@ -803,18 +804,19 @@ LF l_find_mt_newindex(LS *lua) {
   return 0;
 }
 
-// Lua CFunctions
+// Lua CFunctions (stack maintenence is unnecessary)
 
 LF l_cf_ta_buffer_new(LS *lua) {
   new_scintilla_buffer(SCINTILLA(focused_editor), true, true);
-  l_ta_get(lua, "buffers"); lua_rawgeti(lua, -1, lua_objlen(lua, -1));
+  if (!l_ta_get(lua, "buffers")) luaL_error(lua, buffers_dne);
+  lua_rawgeti(lua, -1, lua_objlen(lua, -1));
   return 1;
 }
 
 LF l_cf_buffer_delete(LS *lua) {
   l_check_focused_buffer(lua, 1);
   sptr_t doc = l_checkdocpointer(lua, 1);
-  l_ta_get(lua, "buffers");
+  if (!l_ta_get(lua, "buffers")) luaL_error(lua, buffers_dne);
   if (lua_objlen(lua, -1) > 1)
     l_goto_scintilla_buffer(focused_editor, -1, false);
   else
@@ -901,7 +903,7 @@ void l_create_entry(LS *lua, GtkWidget *c1, GtkWidget *c2, bool vertical) {
 }
 
 LF l_cf_ta_get_split_table(LS *lua) {
-  l_ta_get(lua, "views");
+  if (!l_ta_get(lua, "views")) luaL_error(lua, views_dne);
   if (lua_objlen(lua, -1) > 1) {
     GtkWidget *pane = gtk_widget_get_parent(focused_editor);
     while (GTK_IS_PANED(gtk_widget_get_parent(pane)))