refactor: move command execution into their own file

include/util/command.hpp

@@ -0,0 +1,35 @@
+#pragma once
+
+#include <sys/wait.h>
+
+namespace waybar::util::command {
+
+struct cmd_res {
+  int exit_code;
+  std::string out;
+};
+
+inline struct cmd_res exec(const std::string cmd)
+{
+  FILE* fp(popen(cmd.c_str(), "r"));
+  if (!fp) {
+    return { -1, "" };
+  }
+
+  std::array<char, 128> buffer = {0};
+  std::string output;
+  while (feof(fp) == 0) {
+    if (fgets(buffer.data(), 128, fp) != nullptr) {
+      output += buffer.data();
+    }
+  }
+
+  // Remove last newline
+  if (!output.empty() && output[output.length()-1] == '\n') {
+    output.erase(output.length()-1);
+  }
+  int exit_code = WEXITSTATUS(pclose(fp));
+  return { exit_code, output };
+}
+
+}