terminal.c File Reference

Cross-platform unified color detection and terminal capabilities. More...

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Functions
bool	terminal_should_color_output (int fd)
	Determine if color output should be used.
terminal_color_mode_t	terminal_get_effective_color_mode (void)
	Get current color mode considering all overrides.
bool	terminal_is_stdin_tty (void)
bool	terminal_is_stdout_tty (void)
bool	terminal_is_stderr_tty (void)
bool	terminal_is_interactive (void)
bool	terminal_is_piped_output (void)
bool	terminal_should_force_stderr (void)
bool	terminal_can_prompt_user (void)
int	terminal_choose_log_fd (log_level_t level)

Detailed Description

Cross-platform unified color detection and terminal capabilities.

Definition in file platform/terminal.c.

Function Documentation

terminal_can_prompt_user()

bool terminal_can_prompt_user

(

void

)

Definition at line 169 of file platform/terminal.c.

                                    {
  // Must be fully interactive (stdin and stdout are TTYs)
  if (!terminal_is_interactive()) {
    return false;
  }
 
  // Must not be in snapshot mode (non-interactive capture)
  if (GET_OPTION(snapshot_mode)) {
    return false;
  }
 
  // Must not have automated prompt responses configured
  const char *auto_response = SAFE_GETENV("ASCII_CHAT_QUESTION_PROMPT_RESPONSE");
  if (auto_response && *auto_response != '\0') {
    return false; // Automated responses configured, not interactive
  }
 
  // All checks passed, interactive prompts are appropriate
  return true;
}

References terminal_is_interactive().

Referenced by prompt_unknown_host(), and server_main().

terminal_choose_log_fd()

int terminal_choose_log_fd

(

log_level_t

level

)

Definition at line 190 of file platform/terminal.c.

                                              {
  // When force_stderr is enabled (client mode), send ALL logs to stderr
  // When terminal is NOT interactive (piped/redirected), send ALL logs to stderr
  // to keep stdout clean for piped data (JSON, frames, etc.)
  if (log_get_force_stderr() || !terminal_is_interactive()) {
    return STDERR_FILENO;
  }
 
  // In interactive mode, route based on level:
  // WARN and above (ERROR, FATAL) go to stderr
  // Others (DEV, DEBUG, INFO) go to stdout
  if (level >= LOG_WARN) {
    return STDERR_FILENO;
  }
 
  return STDOUT_FILENO;
}

References log_get_force_stderr(), and terminal_is_interactive().

Referenced by log_console_impl(), log_msg(), and log_plain_msg().

terminal_get_effective_color_mode()

terminal_color_mode_t terminal_get_effective_color_mode

(

void

)

Get current color mode considering all overrides.

Determines effective color mode by checking:

1. –color flag (force enable)
2. –color-mode option (none/16/256/truecolor)
3. Terminal capability detection

Returns

Effective terminal_color_mode_t to use

Definition at line 114 of file platform/terminal.c.

                                                              {
  // If colors are disabled entirely by terminal_should_color_output(), return NONE
  if (!terminal_should_color_output(STDOUT_FILENO)) {
    return TERM_COLOR_NONE;
  }
 
  // If --color-mode is set to specific value, use it
  terminal_color_mode_t color_mode = GET_OPTION(color_mode);
  if (color_mode != TERM_COLOR_AUTO) {
    return color_mode;
  }
 
  // Otherwise auto-detect from terminal capabilities
  // For now, return the detected color mode from terminal capabilities
  // This will be used by apply_color_mode_override() if needed
  return TERM_COLOR_AUTO; // Let the calling code handle auto-detection
}

References terminal_should_color_output().

terminal_is_interactive()

bool terminal_is_interactive

(

void

)

Definition at line 148 of file platform/terminal.c.

                                   {
  return terminal_is_stdin_tty() && terminal_is_stdout_tty();
}

References terminal_is_stdin_tty(), and terminal_is_stdout_tty().

Referenced by main(), server_main(), server_status_display(), server_status_display_interactive(), session_display_create(), session_display_render_frame(), session_render_loop(), splash_intro_start(), terminal_can_prompt_user(), terminal_choose_log_fd(), and threaded_send_terminal_size_with_auto_detect().

terminal_is_piped_output()

bool terminal_is_piped_output

(

void

)

Definition at line 152 of file platform/terminal.c.

                                    {
  return !terminal_is_stdout_tty();
}

References terminal_is_stdout_tty().

Referenced by asciichat_shared_init(), options_init(), and terminal_should_force_stderr().

terminal_is_stderr_tty()

bool terminal_is_stderr_tty

(

void

)

Definition at line 144 of file platform/terminal.c.

                                  {
  return platform_isatty(STDERR_FILENO) != 0;
}

References platform_isatty().

terminal_is_stdin_tty()

bool terminal_is_stdin_tty

(

void

)

Definition at line 136 of file platform/terminal.c.

                                 {
  return platform_isatty(STDIN_FILENO) != 0;
}

References platform_isatty().

Referenced by display_init(), session_display_create(), terminal_is_interactive(), and threaded_send_terminal_size_with_auto_detect().

terminal_is_stdout_tty()

bool terminal_is_stdout_tty

(

void

)

Definition at line 140 of file platform/terminal.c.

                                  {
  return platform_isatty(STDOUT_FILENO) != 0;
}

References platform_isatty().

Referenced by session_client_like_run(), session_display_create(), terminal_is_interactive(), terminal_is_piped_output(), and threaded_send_terminal_size_with_auto_detect().

terminal_should_color_output()

bool terminal_should_color_output

(

int

fd

)

Determine if color output should be used.

Priority order:

1. If –color flag is set → ALWAYS use colors (force override)
2. If CLAUDECODE env var is set → NEVER use colors (LLM automation)
3. If output is not a TTY (piping) → NO colors
4. If –color-mode=none → NO colors (user choice)
5. Otherwise → Use colors

Parameters

fd	File descriptor to check (STDOUT_FILENO or STDERR_FILENO)

Returns

true if colors should be used, false otherwise

Definition at line 31 of file platform/terminal.c.

                                          {
  // Check color_mode setting - if explicitly set to NONE, disable colors
  int color_mode = GET_OPTION(color_mode);
  if (color_mode == COLOR_MODE_NONE) {
    return false; // Color mode explicitly disabled
  }
 
  // Get current color setting (auto/true/false)
  int color_setting = GET_OPTION(color);
 
  // Priority 1: --color=true - Force colors ON (overrides everything)
  if (color_setting == COLOR_SETTING_TRUE) {
    return true; // ALWAYS colorize
  }
 
  // Priority 2: --color=false - Force colors OFF (overrides everything)
  if (color_setting == COLOR_SETTING_FALSE) {
    return false; // NEVER colorize
  }
 
  // Priority 3: --color=auto (default) - Smart detection
  // Special case: Show colors for --help and --version even if not a TTY
  // Check for help/version in global argv (set by main.c early)
  extern int g_argc;
  extern char **g_argv;
  if (g_argc > 1 && g_argv) {
    for (int i = 1; i < g_argc; i++) {
      if (strcmp(g_argv[i], "--help") == 0 || strcmp(g_argv[i], "-h") == 0 || strcmp(g_argv[i], "--version") == 0 ||
          strcmp(g_argv[i], "-v") == 0 || strcmp(g_argv[i], "--show-capabilities") == 0) {
        // For help/version/show-capabilities, use colors only if output is a TTY
        // (respect piping convention: no colors unless --color=true)
        int is_tty = platform_isatty(fd);
        if (!is_tty) {
          // Piping detected - fall through to check environment overrides
          break;
        }
 
        // It's a TTY - show colors for help. Check environment overrides.
        if (SAFE_GETENV("ASCII_CHAT_COLOR")) {
          return true; // ASCII_CHAT_COLOR env var forces colors
        }
 
        // CLAUDECODE environment variable (LLM automation) - disable colors
        if (SAFE_GETENV("CLAUDECODE")) {
          return false; // NO colors in Claude Code environment
        }
 
        // For help output to TTY, show colors by default
        return true;
      }
    }
  }
 
  // Check environment variable overrides
  if (SAFE_GETENV("ASCII_CHAT_COLOR")) {
    return true; // ASCII_CHAT_COLOR env var forces colors
  }
 
  // CLAUDECODE environment variable (LLM automation) - disable colors
  if (SAFE_GETENV("CLAUDECODE")) {
    return false; // NO colors in Claude Code environment
  }
 
  // Check if output is a TTY (pipe detection)
  int is_tty = platform_isatty(fd);
  if (!is_tty) {
    return false; // NO colors when piping/redirecting
  }
 
  // Default: Use colors (we have TTY and no environment overrides)
  return true;
}

References g_argc, g_argv, and platform_isatty().

Referenced by action_show_capabilities_immediate(), action_show_version(), colored_string(), colorize_log_message(), log_plain_msg(), and terminal_get_effective_color_mode().

terminal_should_force_stderr()

bool terminal_should_force_stderr

(

void

)

Definition at line 156 of file platform/terminal.c.

                                        {
  // If stdout is piped/redirected, force logs to stderr to avoid corruption
  if (terminal_is_piped_output()) {
    // Unless in TESTING environment where test framework may capture stdout
    const char *testing = SAFE_GETENV("TESTING");
    if (testing && strcmp(testing, "1") == 0) {
      return false; // Allow stdout in test environments
    }
    return true; // Force stderr when piped
  }
  return false; // stdout is TTY, no need to force stderr
}

References terminal_is_piped_output().

Referenced by main(), session_client_like_run(), and session_display_create().