From 9fe6626a63718635cca6ce8920e1669d099d46a7 Mon Sep 17 00:00:00 2001
From: Bent Bisballe Nyeng <deva@aasimon.org>
Date: Sat, 19 Jun 2021 11:58:12 +0200
Subject: Make self-aware (and recompile/re-launch as needed)

---
 libcppbuild.cc | 53 +++++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 53 insertions(+)

(limited to 'libcppbuild.cc')

diff --git a/libcppbuild.cc b/libcppbuild.cc
index 69d23ba..b400061 100644
--- a/libcppbuild.cc
+++ b/libcppbuild.cc
@@ -18,6 +18,7 @@
 #include "task_ar.h"
 #include "task_so.h"
 #include "settings.h"
+#include "execute.h"
 
 #include <unistd.h>
 
@@ -82,8 +83,60 @@ std::shared_ptr<Task> getNextTask(const std::list<std::shared_ptr<Task>>& allTas
 	return nullptr;
 }
 
+namespace
+{
+// Hack to get command-line args for re-launch
+int g_argc;
+char** g_argv;
+}
+
+// TODO: Use c++20 when ready, somehing like this:
+//void reg(const std::source_location location =
+//         std::source_location::current())
+void reg(const std::string& location)
+{
+	std::filesystem::path configFile(location);
+	std::filesystem::path binFile(configFile.stem());
+	if(std::filesystem::last_write_time(binFile) <=
+	   std::filesystem::last_write_time(configFile))
+	{
+		std::cout << "Rebuilding config\n";
+		auto ret = execute("/usr/bin/g++",
+		                   {
+			                   "-s",
+			                   "-O3",
+			                   "-std=c++17",
+			                   "-pthread",
+			                   configFile.string(),
+			                   "libcppbuild.a",
+			                   "-o",
+			                   binFile.string(),
+			                 });
+		if(ret != 0)
+		{
+			std::cerr << "Failed.\n";
+			exit(1);
+		}
+		else
+		{
+			std::cout << "Re-launch\n";
+			std::vector<std::string> args;
+			for(int i = 1; i < g_argc; ++i)
+			{
+				args.push_back(g_argv[i]);
+			}
+			exit(execute(g_argv[0], args));
+		}
+	}
+
+//	g++ -s -O3 -std=c++17 -pthread $0 libcppbuild.a -o cppbuild
+}
+
 int main(int argc, char* argv[])
 {
+	g_argc = argc;
+	g_argv = argv;
+
 	Settings settings;
 	// TODO: Set from commandline
 	settings.builddir = "build/foo";
-- 
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