From 4fcf7328144269624655c77508d30f0c966d6120 Mon Sep 17 00:00:00 2001
From: Shubhankar Sarangi <shubhankarsarangi@gmail.com>
Date: Sun, 24 Nov 2024 15:58:45 +0530
Subject: [PATCH] impr: Reserve space to avoid multiple allocations when
 loading scripts (#1929)

std::forward ensures that the arguments are perfectly forwarded to
loadScript
By reserving space in the features vector based on the size of scripts,
we can avoid multiple memory allocations during the loop. If an
exception occurs, returning an empty vector immediately clarifies that
no scripts were loaded. Without reservation, each call to emplace_back
could potentially trigger a reallocation if the current capacity is
exceeded, which is costly in terms of performance. This leads to more
efficient memory management and can significantly speed up the execution
time when dealing with a large number of scripts.


![image](https://github.com/user-attachments/assets/3e290162-fb8b-4f00-a71b-6009494b2dab)
---
 .../source/plugin_script_loader.cpp           | 47 ++++++++++---------
 1 file changed, 24 insertions(+), 23 deletions(-)

diff --git a/plugins/script_loader/source/plugin_script_loader.cpp b/plugins/script_loader/source/plugin_script_loader.cpp
index 5e5238886..2c58dd676 100644
--- a/plugins/script_loader/source/plugin_script_loader.cpp
+++ b/plugins/script_loader/source/plugin_script_loader.cpp
@@ -32,32 +32,33 @@ namespace {
             scripts.emplace_back(&script);
     }
 
-    std::vector<const Script*> loadAllScripts() {
-        std::vector<const Script*> scripts;
+std::vector<const Script*> loadAllScripts() {
+    std::vector<const Script*> scripts;
 
-        try {
-            std::apply([&scripts](auto&&... args) {
-                (loadScript(scripts, args), ...);
-            }, s_loaders);
-        } catch (const std::exception &e) {
-            log::error("Error when loading scripts: {}", e.what());
-        }
-
-        {
-            std::vector<hex::Feature> features;
-            for (const auto &script : scripts) {
-                if (!script->background)
-                    continue;
-
-                features.emplace_back(script->name, true);
-            }
-
-            IMHEX_PLUGIN_FEATURES = features;
-        }
-
-        return scripts;
+    try {
+        std::apply([&scripts](auto&&... args) {
+            (loadScript(scripts, std::forward<decltype(args)>(args)), ...);
+        }, s_loaders);
+    } catch (const std::exception &e) {
+        log::error("Error when loading scripts: {}", e.what());
+        return {}; 
     }
 
+    std::vector<hex::Feature> features;
+    features.reserve(scripts.size()); 
+
+    for (const auto &script : scripts) {
+        if (script->background) {
+            features.emplace_back(script->name, true);
+        }
+    }
+
+    IMHEX_PLUGIN_FEATURES = std::move(features); 
+
+    return scripts;
+}
+
+
     void initializeLoader(u32 &count, auto &loader) {
         try {
             if (loader.initialize())