Fix color codes emitting mid-UTF8 code. (#312)

Author: blackhole89

main.cpp

@@ -36,6 +36,36 @@ extern "C" __declspec(dllimport) int __stdcall SetConsoleMode(void* hConsoleHand
 #define ANSI_COLOR_RESET   "\x1b[0m"
 #define ANSI_BOLD          "\x1b[1m"
 
+/* Keep track of current color of output, and emit ANSI code if it changes. */
+enum console_state {
+    CONSOLE_STATE_DEFAULT=0,
+    CONSOLE_STATE_PROMPT,
+    CONSOLE_STATE_USER_INPUT
+}; 
+
+static console_state con_st = CONSOLE_STATE_DEFAULT;
+static bool con_use_color = false;
+
+void set_console_state(console_state new_st)
+{
+    if (!con_use_color) return;
+    // only emit color code if state changed
+    if (new_st != con_st) {
+        con_st = new_st;
+        switch(con_st) {
+        case CONSOLE_STATE_DEFAULT:
+            printf(ANSI_COLOR_RESET);
+            return;
+        case CONSOLE_STATE_PROMPT:
+            printf(ANSI_COLOR_YELLOW);
+            return;
+        case CONSOLE_STATE_USER_INPUT:
+            printf(ANSI_BOLD ANSI_COLOR_GREEN);
+            return;
+        }
+    }
+}
+
 static const int EOS_TOKEN_ID = 2;
 
 // determine number of model parts based on the dimension
@@ -866,7 +896,7 @@ static bool is_interacting = false;
 
 #if defined (__unix__) || (defined (__APPLE__) && defined (__MACH__)) || defined (_WIN32)
 void sigint_handler(int signo) {
-    printf(ANSI_COLOR_RESET);
+    set_console_state(CONSOLE_STATE_DEFAULT);
     printf("\n"); // this also force flush stdout.
     if (signo == SIGINT) {
         if (!is_interacting) {
@@ -925,6 +955,10 @@ int main(int argc, char ** argv) {
         params.prompt = gpt_random_prompt(rng);
     }
 
+    // save choice to use color for later
+    // (note for later: this is a slightly awkward choice)
+    con_use_color = params.use_color;
+
 //    params.prompt = R"(// this function checks if the number n is prime
 //bool is_prime(int n) {)";
 
@@ -1040,18 +1074,18 @@ int main(int argc, char ** argv) {
 
     int remaining_tokens = params.n_predict;
 
-    // set the color for the prompt which will be output initially
-    if (params.use_color) {
 #if defined (_WIN32)
+  if (params.use_color) {
         // Enable ANSI colors on Windows 10+
         unsigned long dwMode = 0;
         void* hConOut = GetStdHandle((unsigned long)-11); // STD_OUTPUT_HANDLE (-11)
         if (hConOut && hConOut != (void*)-1 && GetConsoleMode(hConOut, &dwMode) && !(dwMode & 0x4)) {
             SetConsoleMode(hConOut, dwMode | 0x4); // ENABLE_VIRTUAL_TERMINAL_PROCESSING (0x4)
         }
-#endif
-        printf(ANSI_COLOR_YELLOW);
     }
+#endif
+    // the first thing we will do is to output the prompt, so set color accordingly
+    set_console_state(CONSOLE_STATE_PROMPT);
 
     while (remaining_tokens > 0 || params.interactive) {
         // predict
@@ -1125,8 +1159,8 @@ int main(int argc, char ** argv) {
             fflush(stdout);
         }
         // reset color to default if we there is no pending user input
-        if (!input_noecho && params.use_color && (int)embd_inp.size() == input_consumed) {
-            printf(ANSI_COLOR_RESET);
+        if (!input_noecho && (int)embd_inp.size() == input_consumed) {
+            set_console_state(CONSOLE_STATE_DEFAULT);
         }
 
         // in interactive mode, and not currently processing queued inputs;
@@ -1146,15 +1180,16 @@ int main(int argc, char ** argv) {
                 }
             }
             if (is_interacting) {
+                // potentially set color to indicate we are taking user input
+                set_console_state(CONSOLE_STATE_USER_INPUT);
+
                 if (params.instruct) {
                     input_consumed = embd_inp.size();
                     embd_inp.insert(embd_inp.end(), inp_pfx.begin(), inp_pfx.end());
 
                     printf("\n> ");
                 }
 
-                // currently being interactive
-                if (params.use_color) printf(ANSI_BOLD ANSI_COLOR_GREEN);
                 std::string buffer;
                 std::string line;
                 bool another_line = true;
@@ -1167,7 +1202,9 @@ int main(int argc, char ** argv) {
                     }
                     buffer += line + '\n'; // Append the line to the result
                 } while (another_line);
-                if (params.use_color) printf(ANSI_COLOR_RESET);
+
+                // done taking input, reset color
+                set_console_state(CONSOLE_STATE_DEFAULT);
 
                 std::vector<llama_vocab::id> line_inp = ::llama_tokenize(vocab, buffer, false);
                 embd_inp.insert(embd_inp.end(), line_inp.begin(), line_inp.end());
@@ -1218,9 +1255,7 @@ int main(int argc, char ** argv) {
 
     ggml_free(model.ctx);
 
-    if (params.use_color) {
-        printf(ANSI_COLOR_RESET);
-    }
+    set_console_state(CONSOLE_STATE_DEFAULT);
 
     return 0;
 }