Continue C++ rewrite.

terminal.cc

@@ -0,0 +1,111 @@
+#include "terminal.h"
+#include <sys/ioctl.h>
+#include <unistd.h>
+#include <cstdio>
+#include <cstdlib>
+
+namespace ke {
+
+static Terminal* g_terminal_instance = nullptr;
+
+static void cleanup_terminal_on_exit() {
+    if (g_terminal_instance) {
+        g_terminal_instance->disable_raw_mode();
+    }
+}
+
+Terminal::Terminal() : raw_mode_enabled_(false) {
+    g_terminal_instance = this;
+}
+
+Terminal::~Terminal() {
+    if (raw_mode_enabled_) {
+        disable_raw_mode();
+    }
+    g_terminal_instance = nullptr;
+}
+
+void Terminal::setup() {
+    if (tcgetattr(STDIN_FILENO, &entry_term_) == -1) {
+        perror("can't snapshot terminal settings");
+        exit(1);
+    }
+    atexit(cleanup_terminal_on_exit);
+    enable_raw_mode();
+}
+
+void Terminal::enable_raw_mode() {
+    if (raw_mode_enabled_) {
+        return;
+    }
+    
+    struct termios raw;
+    
+    /* Read the current terminal parameters for standard input. */
+    if (tcgetattr(STDIN_FILENO, &raw) == -1) {
+        perror("tcgetattr while enabling raw mode");
+        exit(1);
+    }
+    
+    /*
+     * Put the terminal into raw mode.
+     */
+    cfmakeraw(&raw);
+    
+    /*
+     * Set timeout for read(2).
+     *
+     * VMIN: what is the minimum number of bytes required for read
+     * to return?
+     *
+     * VTIME: max time before read(2) returns in hundreds of milli-
+     * seconds.
+     */
+    raw.c_cc[VMIN] = 0;
+    raw.c_cc[VTIME] = 1;
+    
+    /*
+     * Now write the terminal parameters to the current terminal,
+     * after flushing any waiting input out.
+     */
+    if (tcsetattr(STDIN_FILENO, TCSAFLUSH, &raw) == -1) {
+        perror("tcsetattr while enabling raw mode");
+        exit(1);
+    }
+    
+    raw_mode_enabled_ = true;
+}
+
+void Terminal::disable_raw_mode() {
+    if (!raw_mode_enabled_) {
+        return;
+    }
+    
+    clear_screen();
+    
+    if (tcsetattr(STDIN_FILENO, TCSAFLUSH, &entry_term_) == -1) {
+        perror("couldn't disable terminal raw mode");
+        exit(1);
+    }
+    
+    raw_mode_enabled_ = false;
+}
+
+int Terminal::get_window_size(int* rows, int* cols) {
+    struct winsize ws;
+    
+    if (ioctl(STDOUT_FILENO, TIOCGWINSZ, &ws) == -1 || ws.ws_col == 0) {
+        return -1;
+    }
+    
+    *cols = ws.ws_col;
+    *rows = ws.ws_row;
+    return 0;
+}
+
+void Terminal::clear_screen() {
+    (void)write(STDOUT_FILENO, "\x1b[2J", 4);
+    (void)write(STDOUT_FILENO, "\x1b[H", 3);
+}
+
+} // namespace ke