initial commitHEADmaster

1 files changed, 180 insertions, 0 deletions

diff --git a/src/terminal.c b/src/terminal.c
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+/*
+** Copyright (c) 2020 D. Richard Hipp
+**
+** This program is free software; you can redistribute it and/or
+** modify it under the terms of the Simplified BSD License (also
+** known as the "2-Clause License" or "FreeBSD License".)
+
+** This program is distributed in the hope that it will be useful,
+** but without any warranty; without even the implied warranty of
+** merchantability or fitness for a particular purpose.
+**
+** Author contact information:
+**   drh@hwaci.com
+**   http://www.hwaci.com/drh/
+**
+*******************************************************************************
+**
+** This file contains code used to query terminal info
+*/
+
+#include "config.h"
+#include "terminal.h"
+#include <assert.h>
+#ifdef _WIN32
+# include <windows.h>
+#else
+#ifdef __EXTENSIONS__
+#include <termio.h>
+#endif
+#include <sys/ioctl.h>
+#include <stdio.h>
+#include <unistd.h>
+#endif
+
+
+
+#if INTERFACE
+/*
+** Terminal size defined in terms of columns and lines.
+*/
+struct TerminalSize {
+  unsigned int nColumns;         /* Number of characters on a single line */
+  unsigned int nLines;           /* Number of lines */
+};
+#endif
+
+
+/* Get the current terminal size by calling a system service.
+**
+** Return 1 on success. This sets the size parameters to the values returned by
+** the system call, when such is supported; set the size to zero otherwise.
+** Return 0 on the system service call failure.
+**
+** Under Linux/bash the size info is also available from env $LINES, $COLUMNS.
+** Or it can be queried using tput `echo -e "lines\ncols"|tput -S`.
+** Technically, this info could be cached, but then we'd need to handle
+** SIGWINCH signal to requery the terminal on resize event.
+*/
+int terminal_get_size(TerminalSize *t){
+  memset(t, 0, sizeof(*t));
+
+#if defined(TIOCGSIZE)
+  {
+    struct ttysize ts;
+    if( ioctl(STDIN_FILENO, TIOCGSIZE, &ts)>=0
+     || ioctl(STDOUT_FILENO, TIOCGSIZE, &ts)>=0
+     || ioctl(STDERR_FILENO, TIOCGSIZE, &ts)>=0
+    ){
+      t->nColumns = ts.ts_cols;
+      t->nLines = ts.ts_lines;
+      return 1;
+    }
+    return 0;
+  }
+#elif defined(TIOCGWINSZ)
+  {
+    struct winsize ws;
+    if( ioctl(STDIN_FILENO, TIOCGWINSZ, &ws)>=0
+     || ioctl(STDOUT_FILENO, TIOCGWINSZ, &ws)>=0
+     || ioctl(STDERR_FILENO, TIOCGWINSZ, &ws)>=0
+    ){
+      t->nColumns = ws.ws_col;
+      t->nLines = ws.ws_row;
+      return 1;
+    }
+    return 0;
+  }
+#elif defined(_WIN32)
+  {
+    CONSOLE_SCREEN_BUFFER_INFO csbi;
+    if( GetConsoleScreenBufferInfo(GetStdHandle(STD_OUTPUT_HANDLE), &csbi)
+     || GetConsoleScreenBufferInfo(GetStdHandle(STD_ERROR_HANDLE), &csbi)
+     || GetConsoleScreenBufferInfo(GetStdHandle(STD_INPUT_HANDLE), &csbi)
+    ){
+      t->nColumns = csbi.srWindow.Right - csbi.srWindow.Left + 1;
+      t->nLines = csbi.srWindow.Bottom - csbi.srWindow.Top + 1;
+      return 1;
+    }
+    return 0;
+  }
+#else
+  return 1;
+#endif
+}
+
+/*
+** Return the terminal's current width in columns when available, otherwise
+** return the specified default value.
+*/
+unsigned int terminal_get_width(unsigned int nDefault){
+  TerminalSize ts;
+  if( terminal_get_size(&ts) ){
+    return ts.nColumns;
+  }
+  return nDefault;
+}
+
+/*
+** Return the terminal's current height in lines when available, otherwise
+** return the specified default value.
+*/
+unsigned int terminal_get_height(unsigned int nDefault){
+  TerminalSize ts;
+  if( terminal_get_size(&ts) ){
+    return ts.nLines;
+  }
+  return nDefault;
+}
+
+/*
+** Return true if it is reasonable is emit VT100 escape codes.
+*/
+int terminal_is_vt100(void){
+  char *zNoColor;
+#ifdef _WIN32
+  if( !win32_terminal_is_vt100(1) ) return 0;
+#endif /* _WIN32 */
+  if( !fossil_isatty(1) ) return 0;
+  zNoColor =fossil_getenv("NO_COLOR");
+  if( zNoColor==0 ) return 1;
+  if( zNoColor[0]==0 ) return 1;
+  if( is_false(zNoColor) ) return 1;
+  return 0;
+}
+
+#ifdef _WIN32
+/*
+** Return true if the Windows console supports VT100 escape codes.
+**
+** Support for VT100 escape codes is enabled by default in Windows Terminal
+** on Windows 10 and Windows 11, and disabled by default in Legacy Consoles
+** and on older versions of Windows. Programs can turn on VT100 support for
+** Legacy Consoles using the ENABLE_VIRTUAL_TERMINAL_PROCESSING flag.
+**
+** NOTE: If this function needs to be called in more complex scenarios with
+** reassigned stdout and stderr streams, the following CRT calls are useful
+** to translate from CRT streams to file descriptors and to Win32 handles:
+**
+**    HANDLE hOutputHandle = (HANDLE)_get_osfhandle(_fileno(<FILE*>));
+*/
+#ifndef ENABLE_VIRTUAL_TERMINAL_PROCESSING
+#define ENABLE_VIRTUAL_TERMINAL_PROCESSING 0x0004
+#endif
+int win32_terminal_is_vt100(int fd){
+  HANDLE hConsole = NULL;
+  DWORD dwConsoleMode;
+  switch( fd ){
+    case 1:
+      hConsole = GetStdHandle(STD_OUTPUT_HANDLE);
+      break;
+    case 2:
+      hConsole = GetStdHandle(STD_ERROR_HANDLE);
+      break;
+  }
+  if( GetConsoleMode(hConsole,&dwConsoleMode) ){
+    return (dwConsoleMode & ENABLE_VIRTUAL_TERMINAL_PROCESSING)!=0;
+  }
+  return 0;
+}
+#endif /* _WIN32 */