Utility function for quoting command lines

src/dds/proc.common.cpp

@@ -0,0 +1,26 @@
+#include "./proc.hpp"
+
+#include <dds/util.hpp>
+
+#include <algorithm>
+#include <array>
+#include <cctype>
+
+using namespace dds;
+
+bool dds::needs_quoting(std::string_view s) {
+    std::string_view okay_chars = "@%-+=:,./|_";
+    const bool all_okay = std::all_of(s.begin(), s.end(), [&](char c) {
+        return std::isalnum(c) || (okay_chars.find(c) != okay_chars.npos);
+    });
+    return !all_okay;
+}
+
+std::string dds::quote_argument(std::string_view s) {
+    if (!needs_quoting(s)) {
+        return std::string(s);
+    }
+    auto new_s = replace(s, "\\", "\\\\");
+    new_s      = replace(s, "\"", "\\\"");
+    return "\"" + new_s + "\"";
+}

src/dds/proc.hpp

@@ -3,9 +3,26 @@
 
 #include <string>
 #include <vector>
+#include <string_view>
 
 namespace dds {
 
+bool needs_quoting(std::string_view);
+
+std::string quote_argument(std::string_view);
+
+template <typename Container>
+std::string quote_command(const Container& c) {
+    std::string acc;
+    for (const auto& arg : c) {
+        acc += quote_argument(arg) + " ";
+    }
+    if (!acc.empty()) {
+        acc.pop_back();
+    }
+    return acc;
+}
+
 struct proc_result {
     int         signal = 0;
     int         retc   = 0;

src/dds/proc.win.cpp

@@ -20,18 +20,10 @@ namespace {
     throw std::system_error(std::error_code(::GetLastError(), std::system_category()), what);
 }
 
-std::string concat_args(const std::vector<std::string>& cmd) {
-    std::stringstream strm;
-    for (const auto& arg : cmd) {
-        strm << arg << ' ';
-    }
-    return strm.str();
-}
-
 }  // namespace
 
 proc_result dds::run_proc(const std::vector<std::string>& cmd) {
-    auto cmd_str = concat_args(cmd);
+    const auto cmd_str = quote_command(cmd);
 
     ::SECURITY_ATTRIBUTES security = {};
     security.bInheritHandle        = TRUE;