Revert "Revert "win,tty: add support for ANSI codes in win10 v1511""

To bring back support for ANSI codes in win10 v1511.

This reverts commit 8cbabaa817.

PR-URL: https://github.com/libuv/libuv/pull/1143
Refs: https://github.com/libuv/libuv/pull/1138
Refs: https://github.com/libuv/libuv/pull/889
Reviewed-By: Saúl Ibarra Corretgé <saghul@gmail.com>
Reviewed-By: Imran Iqbal <imran@imraniqbal.org>

src/win/tty.c

@@ -57,6 +57,9 @@
 
 #define MAX_INPUT_BUFFER_LENGTH 8192
 
+#ifndef ENABLE_VIRTUAL_TERMINAL_PROCESSING
+#define ENABLE_VIRTUAL_TERMINAL_PROCESSING 0x0004
+#endif
 
 static void uv_tty_capture_initial_style(CONSOLE_SCREEN_BUFFER_INFO* info);
 static void uv_tty_update_virtual_window(CONSOLE_SCREEN_BUFFER_INFO* info);
@@ -125,6 +128,14 @@ static char uv_tty_default_fg_bright = 0;
 static char uv_tty_default_bg_bright = 0;
 static char uv_tty_default_inverse = 0;
 
+typedef enum {
+  UV_SUPPORTED,
+  UV_UNCHECKED,
+  UV_UNSUPPORTED
+} uv_vtermstate_t;
+/* Determine whether or not ANSI support is enabled. */
+static uv_vtermstate_t uv__vterm_state = UV_UNCHECKED;
+static void uv__determine_vterm_state(HANDLE handle);
 
 void uv_console_init() {
   if (uv_sem_init(&uv_tty_output_lock, 1))
@@ -168,6 +179,9 @@ int uv_tty_init(uv_loop_t* loop, uv_tty_t* tty, uv_file fd, int readable) {
     /* shared between all uv_tty_t handles. */
     uv_sem_wait(&uv_tty_output_lock);
 
+    if (uv__vterm_state == UV_UNCHECKED)
+      uv__determine_vterm_state(handle);
+
     /* Store the global tty output handle. This handle is used by TTY read */
     /* streams to update the virtual window when a CONSOLE_BUFFER_SIZE_EVENT */
     /* is received. */
@@ -1636,6 +1650,33 @@ static int uv_tty_write_bufs(uv_tty_t* handle,
     uv_buf_t buf = bufs[i];
     unsigned int j;
 
+  if (uv__vterm_state == UV_SUPPORTED && buf.len > 0) {
+    utf16_buf_used = MultiByteToWideChar(CP_UTF8,
+                                         0,
+                                         buf.base,
+                                         buf.len,
+                                         NULL,
+                                         0);
+
+    if (utf16_buf_used == 0) {
+      *error = GetLastError();
+      break;
+    }
+
+    if (!MultiByteToWideChar(CP_UTF8,
+                             0,
+                             buf.base,
+                             buf.len,
+                             utf16_buf,
+                             utf16_buf_used)) {
+      *error = GetLastError();
+      break;
+    }
+
+    FLUSH_TEXT();
+    continue;
+  }
+
     for (j = 0; j < buf.len; j++) {
       unsigned char c = buf.base[j];
 
@@ -2193,3 +2234,24 @@ int uv_tty_reset_mode(void) {
   /* Not necessary to do anything. */
   return 0;
 }
+
+/* Determine whether or not this version of windows supports
+ * proper ANSI color codes. Should be supported as of windows
+ * 10 version 1511, build number 10.0.10586.
+ */
+static void uv__determine_vterm_state(HANDLE handle) {
+  DWORD dwMode = 0;
+
+  if (!GetConsoleMode(handle, &dwMode)) {
+    uv__vterm_state = UV_UNSUPPORTED;
+    return;
+  }
+
+  dwMode |= ENABLE_VIRTUAL_TERMINAL_PROCESSING;
+  if (!SetConsoleMode(handle, dwMode)) {
+    uv__vterm_state = UV_UNSUPPORTED;
+    return;
+  }
+
+  uv__vterm_state = UV_SUPPORTED;
+}

test/test-list.h

@@ -47,6 +47,7 @@ TEST_DECLARE   (semaphore_3)
 TEST_DECLARE   (tty)
 #ifdef _WIN32
 TEST_DECLARE   (tty_raw)
+TEST_DECLARE   (tty_empty_write)
 #endif
 TEST_DECLARE   (tty_file)
 TEST_DECLARE   (tty_pty)
@@ -404,6 +405,7 @@ TASK_LIST_START
   TEST_ENTRY  (tty)
 #ifdef _WIN32
   TEST_ENTRY  (tty_raw)
+  TEST_ENTRY  (tty_empty_write)
 #endif
   TEST_ENTRY  (tty_file)
   TEST_ENTRY  (tty_pty)

test/test-tty.c

@@ -212,6 +212,48 @@ TEST_IMPL(tty_raw) {
   MAKE_VALGRIND_HAPPY();
   return 0;
 }
+
+TEST_IMPL(tty_empty_write) {
+  int r;
+  int ttyout_fd;
+  uv_tty_t tty_out;
+  uv_loop_t* loop = uv_default_loop();
+
+  /* Make sure we have an FD that refers to a tty */
+  HANDLE handle;
+
+  handle = CreateFileA("conout$",
+                       GENERIC_READ | GENERIC_WRITE,
+                       FILE_SHARE_READ | FILE_SHARE_WRITE,
+                       NULL,
+                       OPEN_EXISTING,
+                       FILE_ATTRIBUTE_NORMAL,
+                       NULL);
+  ASSERT(handle != INVALID_HANDLE_VALUE);
+  ttyout_fd = _open_osfhandle((intptr_t) handle, 0);
+
+  ASSERT(ttyout_fd >= 0);
+
+  ASSERT(UV_TTY == uv_guess_handle(ttyout_fd));
+
+  r = uv_tty_init(uv_default_loop(), &tty_out, ttyout_fd, 0);  /* Writable. */
+  ASSERT(r == 0);
+
+  char dummy[1];
+  uv_buf_t bufs[1];
+  bufs[0].len = 0;
+  bufs[0].base = &dummy;
+
+  r = uv_try_write((uv_stream_t*) &tty_out, bufs, 1);
+  ASSERT(r == 0);
+
+  uv_close((uv_handle_t*) &tty_out, NULL);
+
+  uv_run(loop, UV_RUN_DEFAULT);
+
+  MAKE_VALGRIND_HAPPY();
+  return 0;
+}
 #endif