localPackages.biu: add exec

flake.nix

@@ -184,12 +184,9 @@
         {
           biu = pkgs.mkShell
           {
-            packages = with pkgs; [ pkg-config cmake ninja clang-tools_17 ];
-            buildInputs =
-              (with pkgs; [ fmt boost magic-enum libbacktrace eigen range-v3 ])
-              ++ (with pkgs.localPackages; [ concurrencpp tgbot-cpp nameof ]);
-            # hardeningDisable = [ "all" ];
-            # NIX_DEBUG = "1";
+            inputsFrom = with pkgs.localPackages; [ biu ];
+            buildInputs = [ pkgs.clang-tools_17 ];
+            CMAKE_EXPORT_COMPILE_COMMANDS = "1";
           };
           hpcstat = pkgs.mkShell
           {

local/pkgs/biu/.clangd

@@ -0,0 +1,3 @@
+CompileFlags:
+  Add: [ -Wall, -Wextra, -std=c++23 ]
+  Compiler: gcc

local/pkgs/biu/README.md

@@ -7,6 +7,11 @@ std::size_t hash(auto&&... objs);
 void unused(auto&&...);
 // block forever
 void block_forever();
+detail_::ExecResult exec
+(
+  std::filesystem::path program, std::vector<std::string> args, std::optional<std::string> stdin,
+  std::map<std::string, std::string> extra_env
+);
 
 using int128_t = ...;
 using uint128_t = ...;

local/pkgs/biu/include/biu/common.hpp

@@ -1,5 +1,6 @@
 # pragma once
 # include <regex>
+# include <filesystem>
 # include <fmt/format.h>
 # include <magic_enum_all.hpp>
 
@@ -62,5 +63,12 @@ namespace biu
     }
     template <typename T, typename Fallback = void> using FallbackIfNoTypeDeclared
       = typename detail_::FallbackIfNoTypeDeclaredHelper<T, Fallback>::Type;
+
+    namespace detail_ { struct ExecResult { int exit_code; std::string stdout, stderr; }; }
+    detail_::ExecResult exec
+    (
+      std::filesystem::path program, std::vector<std::string> args, std::optional<std::string> stdin,
+      std::map<std::string, std::string> extra_env
+    );
   }
 }

local/pkgs/biu/src/common.cpp

@@ -1,14 +1,44 @@
 # include <future>
 # include <utility>
 # include <biu.hpp>
+# include <boost/process.hpp>
 
 namespace biu
 {
   std::regex literals::operator""_re(const char* str, std::size_t len)
     { return std::regex{str, len}; }
-  void common::block_forever()
+  namespace common
   {
-    std::promise<void>().get_future().wait();
-    std::unreachable();
+    void block_forever() { std::promise<void>().get_future().wait(); std::unreachable(); }
+    detail_::ExecResult exec
+    (
+      std::filesystem::path program, std::vector<std::string> args, std::optional<std::string> stdin,
+      std::map<std::string, std::string> extra_env
+    )
+    {
+      namespace bp = boost::process;
+      bp::ipstream stdout, stderr;
+      bp::opstream input;
+      std::unique_ptr<bp::child> process;
+      bp::environment env = boost::this_process::environment();
+      for (const auto& [key, value] : extra_env) env[key] = value;
+      if (stdin)
+      {
+        process = std::make_unique<bp::child>
+          (program.string(), bp::args(args), bp::std_out > stdout, bp::std_err > stderr, bp::std_in < input, env);
+        input << *stdin;
+        input.pipe().close();
+      }
+      else process = std::make_unique<bp::child>
+        (program.string(), bp::args(args), bp::std_out > stdout, bp::std_err > stderr, bp::std_in < bp::null, env);
+      process->wait();
+      return
+      {
+        process->exit_code(),
+        std::string{std::istreambuf_iterator<char>{stdout.rdbuf()}, {}},
+        std::string{std::istreambuf_iterator<char>{stderr.rdbuf()}, {}}
+      };
+    }
   }
+
 }