Initial commit

1 files changed, 446 insertions, 0 deletions

diff --git a/sdn.cpp b/sdn.cpp
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+++ b/sdn.cpp
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+//
+// sdn: simple directory navigator
+//
+// Copyright (c) 2017, Přemysl Janouch <p.janouch@gmail.com>
+//
+// Permission to use, copy, modify, and/or distribute this software for any
+// purpose with or without fee is hereby granted, provided that the above
+// copyright notice and this permission notice appear in all copies.
+//
+// THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
+// WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
+// MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY
+// SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
+// WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION
+// OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN
+// CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
+//
+
+#include <string>
+#include <vector>
+#include <locale>
+#include <iostream>
+#include <algorithm>
+#include <cwchar>
+#include <climits>
+
+#include <ncurses.h>
+#include <unistd.h>
+#include <dirent.h>
+#include <sys/stat.h>
+#include <sys/inotify.h>
+#include <fcntl.h>
+
+// Unicode is complex enough already and we might make assumptions
+#ifndef __STDC_ISO_10646__
+#error Unicode required for wchar_t
+#endif
+
+using namespace std;
+
+// For some reason handling of encoding in C and C++ is extremely annoying
+// and C++17 ironically obsoletes C++11 additions that made it less painful
+static wstring
+to_wide (const string &multi) {
+	wstring wide; wchar_t w; mbstate_t mb {};
+	size_t n = 0, len = multi.length () + 1;
+	while (auto res = mbrtowc (&w, multi.c_str () + n, len - n, &mb)) {
+		if (res == size_t (-1) || res == size_t (-2))
+			return L"/invalid encoding/";
+
+		n += res;
+		wide += w;
+	}
+	return wide;
+}
+
+static string
+to_mb (const wstring &wide) {
+	string mb; char buf[MB_LEN_MAX + 1]; mbstate_t mbs {};
+	for (size_t n = 0; n <= wide.length (); n++) {
+		auto res = wcrtomb (buf, wide.c_str ()[n], &mbs);
+		if (res == size_t (-1))
+			throw invalid_argument ("invalid encoding");
+		mb.append (buf, res);
+	}
+	// There's one extra NUL character added by wcrtomb()
+	mb.erase (mb.length () - 1);
+	return mb;
+}
+
+static int
+print (const wstring &wide, int limit) {
+	int total_width = 0;
+	for (wchar_t w : wide) {
+		// TODO: controls as ^X, show in inverse
+		if (!isprint (w))
+			w = L'?';
+
+		int width = wcwidth (w);
+		if (total_width + width > limit)
+			break;
+
+		cchar_t c = {};
+		c.chars[0] = w;
+		add_wch (&c);
+		total_width += width;
+	}
+	return total_width;
+}
+
+static int
+prefix (const wstring &in, const wstring &of) {
+	int score = 0;
+	for (size_t i = 0; i < of.size () && in.size () >= i && in[i] == of[i]; i++)
+		score++;
+	return score;
+}
+
+static string
+shell_escape (const string &v) {
+	string result;
+	for (auto c : v)
+		if (c == '\'')
+			result += "'\\''";
+		else
+			result += c;
+	return "'" + result + "'";
+}
+
+// --- Application -------------------------------------------------------------
+
+#define CTRL 31 &
+
+struct entry {
+	string filename;
+	struct stat info;
+	bool operator< (const entry &other) {
+		auto a = S_ISDIR (info.st_mode);
+		auto b = S_ISDIR (other.info.st_mode);
+		return (a && !b) || (a == b && filename < other.filename);
+	}
+};
+
+// Between std and ncurses, make at least the globals stand out
+static struct {
+	string cwd;
+	vector<entry> entries;
+	int offset, cursor;
+	string chosen;
+	bool chosen_full;
+	int inotify_fd, inotify_wd = -1;
+	bool out_of_date;
+
+	wchar_t editor;
+	wstring editor_line;
+} g;
+
+static inline int visible_lines () { return LINES - 2; }
+
+static void
+update () {
+	erase ();
+
+	attrset (A_BOLD);
+	mvprintw (0, 0, "%s", g.cwd.c_str ());
+	if (g.out_of_date)
+		addstr (" [+]");
+
+	for (int i = 0; i < visible_lines (); i++) {
+		int index = g.offset + i;
+		if (index >= int (g.entries.size ()))
+			break;
+
+		attrset (0);
+		if (index == g.cursor)
+			attron (A_REVERSE);
+
+		move (2 + i, 0);
+		auto &entry = g.entries[index];
+
+		// TODO display more information from "info"
+		char modes[] = "- ";
+		const auto &stat = entry.info;
+		if (S_ISDIR  (stat.st_mode)) modes[0] = 'd';
+		if (S_ISBLK  (stat.st_mode)) modes[0] = 'b';
+		if (S_ISCHR  (stat.st_mode)) modes[0] = 'c';
+		if (S_ISLNK  (stat.st_mode)) modes[0] = 'l';
+		if (S_ISFIFO (stat.st_mode)) modes[0] = 'p';
+		if (S_ISSOCK (stat.st_mode)) modes[0] = 's';
+		addstr (modes);
+
+		// TODO show symbolic link target
+		auto width = COLS - 2;
+		hline (' ', width - print (to_wide (entry.filename), width));
+	}
+
+	attrset (0);
+	if (g.editor) {
+		move (1, 0);
+		wchar_t prefix[] = { g.editor, L' ', L'\0' };
+		addwstr (prefix);
+		move (1, print (g.editor_line, COLS - 3) + 2);
+		curs_set (1);
+	} else
+		curs_set (0);
+
+	refresh ();
+}
+
+static void
+reload () {
+	char buf[4096];
+	g.cwd = getcwd (buf, sizeof buf);
+
+	auto dir = opendir (".");
+	g.entries.clear ();
+	while (auto f = readdir (dir)) {
+		// Two dots are for navigation but this ain't as useful
+		if (f->d_name == string ("."))
+			continue;
+
+		struct stat sb = {};
+		lstat (f->d_name, &sb);
+		g.entries.push_back ({ f->d_name, sb });
+	}
+	closedir (dir);
+	sort (begin (g.entries), end (g.entries));
+	g.out_of_date = false;
+
+	g.cursor = min (g.cursor, int (g.entries.size ()) - 1);
+	g.offset = min (g.offset, int (g.entries.size ()) - 1);
+	update ();
+
+	if (g.inotify_wd != -1)
+		inotify_rm_watch (g.inotify_fd, g.inotify_wd);
+
+	g.inotify_wd = inotify_add_watch (g.inotify_fd, buf,
+		IN_ALL_EVENTS | IN_ONLYDIR);
+}
+
+static void
+search (const wstring &needle) {
+	int best = g.cursor, best_n = 0;
+	for (int i = 0; i < int (g.entries.size ()); i++) {
+		auto o = (i + g.cursor) % g.entries.size ();
+		int n = prefix (to_wide (g.entries[o].filename), needle);
+		if (n > best_n) {
+			best = o;
+			best_n = n;
+		}
+	}
+	g.cursor = best;
+}
+
+static void
+handle_editor (wint_t c, bool is_char) {
+	if (c == 27 || c == (CTRL L'g')) {
+		g.editor_line.clear ();
+		g.editor = 0;
+	} else if (c == L'\r' || (!is_char && c == KEY_ENTER)) {
+		if (g.editor == L'e') {
+			auto mb = to_mb (g.editor_line);
+			rename (g.entries[g.cursor].filename.c_str (), mb.c_str ());
+			reload ();
+		}
+		g.editor_line.clear ();
+		g.editor = 0;
+	} else if (is_char) {
+		g.editor_line += c;
+		if (g.editor == L'/'
+		 || g.editor == L's')
+			search (g.editor_line);
+	} else if (c == KEY_BACKSPACE) {
+		if (!g.editor_line.empty ())
+			g.editor_line.erase (g.editor_line.length () - 1);
+	} else
+		beep ();
+}
+
+static bool
+handle (wint_t c, bool is_char) {
+	// If an editor is active, let it handle the key instead and eat it
+	if (g.editor) {
+		handle_editor (c, is_char);
+		c = WEOF;
+	}
+
+	// Translate the Alt key into a bit outside the range of Unicode
+	enum { ALT = 1 << 24 };
+	if (c == 27) {
+		if (get_wch (&c) == ERR) {
+			beep ();
+			return true;
+		}
+		c |= ALT;
+	}
+
+	const auto &current = g.entries[g.cursor];
+	switch (c) {
+	case ALT | L'\r':
+	case ALT | KEY_ENTER:
+		g.chosen_full = true;
+		g.chosen = current.filename;
+		return false;
+	case L'\r':
+	case KEY_ENTER:
+	{
+		bool is_dir = S_ISDIR (current.info.st_mode) != 0;
+		// Dive into directories and accessible symlinks to them
+		if (S_ISLNK (current.info.st_mode)) {
+			char buf[PATH_MAX];
+			struct stat sb = {};
+			auto len = readlink (current.filename.c_str (), buf, sizeof buf);
+			is_dir = len > 0 && size_t (len) < sizeof buf
+				&& !stat (current.filename.c_str (), &sb)
+				&& S_ISDIR (sb.st_mode) != 0;
+		}
+		if (!is_dir) {
+			g.chosen = current.filename;
+			return false;
+		}
+		if (!chdir (current.filename.c_str ())) {
+			g.cursor = 0;
+			reload ();
+		}
+		break;
+	}
+
+	// M-o ought to be the same shortcut the navigator is launched with
+	case ALT | L'o':
+	case L'q':
+		return false;
+
+	case L'k': case CTRL L'p': case KEY_UP:
+		g.cursor--;
+		break;
+	case L'j': case CTRL L'n': case KEY_DOWN:
+		g.cursor++;
+		break;
+	case L'g': case ALT | L'<': case KEY_HOME:
+		g.cursor = 0;
+		break;
+	case L'G': case ALT | L'>': case KEY_END:
+		g.cursor = int (g.entries.size ()) - 1;
+		break;
+
+	case KEY_PPAGE: g.cursor -= LINES; break;
+	case KEY_NPAGE: g.cursor += LINES; break;
+
+	case CTRL L'e': g.offset++; break;
+	case CTRL L'y': g.offset--; break;
+
+	case ALT | L'e':
+		g.editor_line = to_wide (current.filename);
+		// Fall-through
+	case L'e':
+		g.editor = c & ~ALT;
+		break;
+	case L'/':
+	case L's':
+		g.editor = c;
+		break;
+
+	case CTRL L'L':
+		clear ();
+		break;
+	case L'r':
+		reload ();
+		break;
+	case KEY_RESIZE:
+	case WEOF:
+		break;
+	default:
+		beep ();
+	}
+	g.cursor = max (g.cursor, 0);
+	g.cursor = min (g.cursor, int (g.entries.size ()) - 1);
+
+	// Make sure cursor is visible
+	g.offset = max (g.offset, 0);
+	g.offset = min (g.offset, int (g.entries.size ()) - 1);
+
+	if (g.offset > g.cursor)
+		g.offset = g.cursor;
+	if (g.cursor - g.offset >= visible_lines ())
+		g.offset = g.cursor - visible_lines () + 1;
+
+	update ();
+	return true;
+}
+
+static void
+inotify_check () {
+	// Only provide simple indication that contents might have changed
+	char buf[4096]; ssize_t len;
+	bool changed = false;
+	while ((len = read (g.inotify_fd, buf, sizeof buf)) > 0) {
+		const inotify_event *e;
+		for (char *ptr = buf; ptr < buf + len; ptr += sizeof *e + e->len) {
+			e = (const inotify_event *) buf;
+			if (e->wd == g.inotify_wd)
+				changed = true;
+		}
+	}
+	if (changed)
+		update ();
+}
+
+int
+main (int argc, char *argv[]) {
+	(void) argc;
+	(void) argv;
+
+	// That bitch zle closes stdin before exec without redirection
+	(void) close (STDIN_FILENO);
+	if (open ("/dev/tty", O_RDWR)) {
+		cerr << "cannot open tty" << endl;
+		return 1;
+	}
+
+	// Save the original stdout and force ncurses to use the terminal directly
+	auto output_fd = dup (STDOUT_FILENO);
+	dup2 (STDIN_FILENO, STDOUT_FILENO);
+
+	if ((g.inotify_fd = inotify_init1 (IN_NONBLOCK)) < 0) {
+		cerr << "cannot initialize inotify" << endl;
+		return 1;
+	}
+
+	locale::global (locale (""));
+	if (!initscr () || cbreak () == ERR || noecho () == ERR || nonl () == ERR
+	 || halfdelay (1) == ERR || keypad (stdscr, TRUE) == ERR) {
+		cerr << "cannot initialize screen" << endl;
+		return 1;
+	}
+
+	reload ();
+	auto start_dir = g.cwd;
+
+	wint_t c;
+	while (1) {
+		inotify_check ();
+		int res = get_wch (&c);
+		if (res != ERR && !handle (c, res == OK))
+			break;
+	}
+	endwin ();
+
+	// Presumably it is going to end up as an argument, so quote it
+	if (!g.chosen.empty ())
+		g.chosen = shell_escape (g.chosen);
+
+	// We can't portably create a standard stream from an FD, so modify the FD
+	dup2 (output_fd, STDOUT_FILENO);
+
+	if (g.chosen_full) {
+		auto full_path = g.cwd + "/" + g.chosen;
+		cout << "local insert=" << shell_escape (full_path) << endl;
+		return 0;
+	}
+	if (g.cwd != start_dir)
+		cout << "local cd=" << shell_escape (g.cwd) << endl;
+	if (!g.chosen.empty ())
+		cout << "local insert=" << shell_escape (g.chosen) << endl;
+	return 0;
+}