logger: remove ANSI seqences if not terminal

This allows use of raw ANSI sequences instead of the rang stuff.

src/debug.h

@@ -276,6 +276,10 @@ public:
 
                 std::string msg = oss.str();
 
+                if (!get_log_output().is_interactive()) {
+                        msg = prune_ansi_sequences_str(msg.c_str());
+                }
+
                 auto buf = get_log_output().get_buffer();
                 buf.append(msg);
                 buf.submit();

src/utils/color_out.cpp

@@ -48,6 +48,7 @@
 #include "utils/color_out.h"
 
 using std::cout;
+using std::string;
 
 static bool color_stdout;
 
@@ -180,7 +181,8 @@ bool color_output_init() {
         return color_stdout;
 }
 
-static int prune_ansi_sequences(const char *in, char *out) {
+template<class OutputIt>
+static int prune_ansi_sequences(const char *in, OutputIt out) {
         char c = *in;
         bool in_control = false;
         int written = 0;
@@ -207,6 +209,12 @@ static int prune_ansi_sequences(const char *in, char *out) {
         return written;
 }
 
+string prune_ansi_sequences_str(const char *in) {
+        string out;
+        prune_ansi_sequences(in, std::back_inserter(out));
+        return out;
+}
+
 int color_printf(const char *format, ...) {
         va_list ap;
         va_start(ap, format);

src/utils/color_out.h

@@ -114,6 +114,10 @@ bool isMsysPty(int fd);
 
 #ifdef __cplusplus
 #include <iostream>
+#include <string>
+
+std::string prune_ansi_sequences_str(const char *in);
+
 /**
  * Class wrapping color output to terminal. Sample usage:
  *