From 16031a8ca3e6e36e39b5ac52853f39e559f0460a Mon Sep 17 00:00:00 2001
From: Roland Reichwein <mail@reichwein.it>
Date: Wed, 1 May 2024 21:44:11 +0200
Subject: Create dependencies

---
 Makefile  |  2 +-
 xmake.cpp | 47 +++++++++++++++++++++++++++++++++++++++++++----
 2 files changed, 44 insertions(+), 5 deletions(-)

diff --git a/Makefile b/Makefile
index 011a775..63816fc 100644
--- a/Makefile
+++ b/Makefile
@@ -6,7 +6,7 @@ OBJ=$(SRC:.cpp=.o)
 
 all: $(PROJECTNAME)
 
-LDLIBS += -lfmt
+LDLIBS += -lfmt -lreichwein
 CXXFLAGS += -std=c++17
 
 $(PROJECTNAME): $(OBJ)
diff --git a/xmake.cpp b/xmake.cpp
index e4cadfb..4c6fdbe 100644
--- a/xmake.cpp
+++ b/xmake.cpp
@@ -1,8 +1,10 @@
 #include "xmake.h"
 
+#include <algorithm>
 #include <cstdlib>
 #include <filesystem>
 #include <iostream>
+#include <iterator>
 #include <sstream>
 #include <stdexcept>
 #include <string>
@@ -15,6 +17,9 @@
 
 #include <fmt/format.h>
 
+#include <libreichwein/file.h>
+#include <libreichwein/stringhelper.h>
+
 namespace fs = std::filesystem;
 namespace bp = boost::process;
 namespace pt = boost::property_tree;
@@ -69,6 +74,37 @@ namespace {
   return false;
  }
 
+ std::vector<fs::path> deps_from_depfile(const fs::path& path) {
+  std::string depfile_content{Reichwein::File::getFile(path)};
+  std::vector<std::string> parts {Reichwein::Stringhelper::split(depfile_content, ":\r\n")};
+  if (parts.size() >= 2) {
+   std::vector<std::string> deps {Reichwein::Stringhelper::split(parts[1], " ")};
+   std::vector<fs::path> result;
+   std::transform(deps.cbegin(), deps.cend(), std::back_inserter(result), [](const std::string& s){ return s; });
+   return result;
+  } else {
+   throw std::runtime_error("Bad depfile contents: "s + path.string());
+  }
+ }
+
+ // return contained dependencies
+ // input: cpp
+ std::vector<fs::path> make_depfile_from(const fs::path& p) {
+  fs::path depfile{p};
+  depfile.replace_extension("d");
+
+  // check if depfile exists and if it contains up to date info
+  if (!fs::exists(depfile) || is_outdated(depfile, deps_from_depfile(depfile))) {
+   // actually create depfile
+   int result{system(fmt::format("g++ -MM -MF {} -c {}", depfile.string(), p.string()).c_str())};
+   if (result != 0) {
+    throw std::runtime_error(fmt::format("Depfile {} can't be created", depfile.string()));
+   }
+  }
+
+  return deps_from_depfile(depfile);
+ }
+
  void build(const pt::ptree& ptree) {
   fs::path target{get_target(ptree)};
   std::vector<fs::path> objects{get_objects(ptree)};
@@ -81,14 +117,14 @@ namespace {
    std::cout << "  " << i << std::endl;
   }
 
+  std::cout << "Calculating dependencies..." << std::endl;
   std::unordered_map<fs::path, std::vector<fs::path>> dependencies;
   dependencies.emplace(target, objects);
   for (const auto& p: sources) {
    fs::path p_obj{p};
    p_obj.replace_extension("o");
-   dependencies.emplace(p_obj, std::vector<fs::path>{p});
-   // TODO: add headers dependencies:
-   // g++ -MM -MF <depsfile> -c <cppfile>
+   std::vector<fs::path> deps {make_depfile_from(p)};
+   dependencies.emplace(p_obj, deps);
   }
 
   std::vector<std::string> commands;
@@ -107,7 +143,7 @@ namespace {
    for (auto &i: objects) {
     link_command += fmt::format(" {}", i.string());
    }
-   link_command += " -lfmt";
+   link_command += " -lfmt -lreichwein";
    link_command += fmt::format(" -o {}", target.string());
    commands.push_back(link_command);
   }
@@ -138,6 +174,9 @@ namespace {
   std::vector<std::string> commands;
   for (auto &i: cleanlist) {
    commands.push_back(fmt::format("rm -f {}", i.string()));
+   fs::path dep{i};
+   dep.replace_extension("d");
+   commands.push_back(fmt::format("rm -f {}", dep.string()));
   }
 
   std::cout << "Running commands: " << std::endl;
-- 
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