log: use ANSI colors for strings containing "warning" or "error"

common/cmdlib.cc

@@ -37,6 +37,7 @@
 
 #include <cstdint>
 
+#include <algorithm>
 #include <string>
 
 /* set these before calling CheckParm */
@@ -405,4 +406,15 @@ bool natstrlt(const char *s1, const char *s2, bool case_sensitive)
     if (*p1 != 0 && *p2 == 0)
         return false;
     return false;
-}
+}
+
+std::string_view::const_iterator string_ifind(std::string_view haystack, std::string_view needle)
+{
+    return std::search(haystack.begin(), haystack.end(), needle.begin(), needle.end(),
+        [](char a, char b) { return tolower(a) == tolower(b); });
+}
+
+bool string_icontains(std::string_view haystack, std::string_view needle)
+{
+    return string_ifind(haystack, needle) != haystack.end();
+}

common/log.cc

@@ -68,6 +68,19 @@ void print(flag logflag, const char *str)
         return;
     }
 
+    static const char *escape_red = "\033[31m";
+    static const char *escape_yellow = "\033[33m";
+    static const char *escape_reset = "\033[0m";
+
+    std::string ansi_str;
+    if (string_icontains(str, "error")) {
+        ansi_str = fmt::format("{}{}{}", escape_red, str, escape_reset);
+    } else if (string_icontains(str, "warning")) {
+        ansi_str = fmt::format("{}{}{}", escape_yellow, str, escape_reset);
+    } else {
+        ansi_str = str;
+    }
+
     print_mutex.lock();
  
     if (logflag != flag::PERCENT) {
@@ -79,12 +92,12 @@ void print(flag logflag, const char *str)
 
 #ifdef _WIN32
         // print to windows console
-        OutputDebugStringA(str);
+        OutputDebugStringA(ansi_str.c_str());
 #endif
     }
 
     // stdout
-    std::cout << str;
+    std::cout << ansi_str;
 
     print_mutex.unlock();
 }

include/common/cmdlib.hh

@@ -136,6 +136,11 @@ struct natural_case_insensitive_less
     bool operator()(const std::string &l, const std::string &r) const noexcept { return stlnatstrlt(l, r, false); }
 };
 
+#include <string_view>
+
+std::string_view::const_iterator string_ifind(std::string_view haystack, std::string_view needle);
+bool string_icontains(std::string_view haystack, std::string_view needle);
+
 #include <chrono>
 
 using qclock = std::chrono::high_resolution_clock;