Add change config file and run config file

src/clippy/config.cpp

@@ -0,0 +1,52 @@
+#include <clippy/config.hpp>
+#include <clippy/target.hpp>
+
+#include <fstream>
+#include <algorithm>
+
+std::string Strip(std::string s) {
+  while (!s.empty() && std::isspace(s.back())) {
+    s.pop_back();
+  }
+  std::reverse(s.begin(), s.end());
+  while (!s.empty() && std::isspace(s.back())) {
+    s.pop_back();
+  }
+  std::reverse(s.begin(), s.end());
+
+  return s;
+}
+
+std::unique_ptr<clippy::targets::Target> Config::GetTarget(
+    const std::string& target) {
+  std::ifstream in(path_);
+
+  std::string current;
+  std::vector<std::string> target_commands;
+
+  bool target_begin = false;
+
+  while (std::getline(in, current)) {
+    if (current == target + ":") {
+      target_begin = true;
+      continue;
+    }
+    if (current.empty()) {
+      continue;
+    }
+    if (!std::isspace(current[0]) && target_begin) {
+      break;
+    }
+
+    if (target_begin) {
+      target_commands.emplace_back(Strip(std::move(current)));
+    }
+  }
+
+  if (!target_begin) {
+    return nullptr;
+  }
+
+  return std::make_unique<clippy::targets::RunShellScript>(
+      std::move(target_commands));
+}