Add a new completion API for experimental plugins feature. (#5000)

Co-authored-by: Rasmus Karlsson <rasmus.karlsson@pajlada.com>

src/controllers/plugins/LuaUtilities.cpp

@@ -4,6 +4,7 @@
 #    include "common/Channel.hpp"
 #    include "common/QLogging.hpp"
 #    include "controllers/commands/CommandContext.hpp"
+#    include "controllers/plugins/LuaAPI.hpp"
 
 #    include <lauxlib.h>
 #    include <lua.h>
@@ -75,6 +76,9 @@ QString humanErrorText(lua_State *L, int errCode)
         case LUA_ERRFILE:
             errName = "(file error)";
             break;
+        case ERROR_BAD_PEEK:
+            errName = "(unable to convert value to c++)";
+            break;
         default:
             errName = "(unknown error type)";
     }
@@ -111,6 +115,7 @@ StackIdx push(lua_State *L, const std::string &str)
 
 StackIdx push(lua_State *L, const CommandContext &ctx)
 {
+    StackGuard guard(L, 1);
     auto outIdx = pushEmptyTable(L, 2);
 
     push(L, ctx.words);
@@ -127,8 +132,27 @@ StackIdx push(lua_State *L, const bool &b)
     return lua_gettop(L);
 }
 
+StackIdx push(lua_State *L, const int &b)
+{
+    lua_pushinteger(L, b);
+    return lua_gettop(L);
+}
+
+bool peek(lua_State *L, bool *out, StackIdx idx)
+{
+    StackGuard guard(L);
+    if (!lua_isboolean(L, idx))
+    {
+        return false;
+    }
+
+    *out = bool(lua_toboolean(L, idx));
+    return true;
+}
+
 bool peek(lua_State *L, double *out, StackIdx idx)
 {
+    StackGuard guard(L);
     int ok{0};
     auto v = lua_tonumberx(L, idx, &ok);
     if (ok != 0)
@@ -140,6 +164,7 @@ bool peek(lua_State *L, double *out, StackIdx idx)
 
 bool peek(lua_State *L, QString *out, StackIdx idx)
 {
+    StackGuard guard(L);
     size_t len{0};
     const char *str = lua_tolstring(L, idx, &len);
     if (str == nullptr)
@@ -156,6 +181,7 @@ bool peek(lua_State *L, QString *out, StackIdx idx)
 
 bool peek(lua_State *L, QByteArray *out, StackIdx idx)
 {
+    StackGuard guard(L);
     size_t len{0};
     const char *str = lua_tolstring(L, idx, &len);
     if (str == nullptr)
@@ -172,6 +198,7 @@ bool peek(lua_State *L, QByteArray *out, StackIdx idx)
 
 bool peek(lua_State *L, std::string *out, StackIdx idx)
 {
+    StackGuard guard(L);
     size_t len{0};
     const char *str = lua_tolstring(L, idx, &len);
     if (str == nullptr)
@@ -186,6 +213,23 @@ bool peek(lua_State *L, std::string *out, StackIdx idx)
     return true;
 }
 
+bool peek(lua_State *L, api::CompletionList *out, StackIdx idx)
+{
+    StackGuard guard(L);
+    int typ = lua_getfield(L, idx, "values");
+    if (typ != LUA_TTABLE)
+    {
+        lua_pop(L, 1);
+        return false;
+    }
+    if (!lua::pop(L, &out->values, -1))
+    {
+        return false;
+    }
+    lua_getfield(L, idx, "hide_others");
+    return lua::pop(L, &out->hideOthers);
+}
+
 QString toString(lua_State *L, StackIdx idx)
 {
     size_t len{};