Implement new line editing "library"

Losing tab complete and text macros, for now.

This new implementation works on an instance of a struct and does
not interact with the rest of catgirl, making it possible to copy
into another project. Unlike existing line editing libraries, this
one is entirely abstract and can be rendered externally.

My goal with this library is to be able to implement vi mode. Since
it operates on struct instances rather than globals, it might also
be possible to give catgirl separate line editing buffers for each
window, which would be a nice UX improvement.

1 files changed, 220 insertions, 232 deletions

diff --git a/edit.c b/edit.c
index 66b5302..21061d7 100644
--- a/edit.c
+++ b/edit.c
@@ -1,4 +1,4 @@
-/* Copyright (C) 2020  C. McEnroe <june@causal.agency>
+/* Copyright (C) 2020, 2022  June McEnroe <june@causal.agency>
  *
  * This program is free software: you can redistribute it and/or modify
  * it under the terms of the GNU General Public License as published by
@@ -13,8 +13,6 @@
  * You should have received a copy of the GNU General Public License
  * along with this program.  If not, see <https://www.gnu.org/licenses/>.
  *
- * Additional permission under GNU GPL version 3 section 7:
- *
  * If you modify this Program, or any covered work, by linking or
  * combining it with OpenSSL (or a modified version of that library),
  * containing parts covered by the terms of the OpenSSL License and the
@@ -25,282 +23,272 @@
  * covered work.
  */
 
-#include <assert.h>
+#include <errno.h>
 #include <limits.h>
 #include <stdbool.h>
-#include <stdio.h>
 #include <stdlib.h>
 #include <wchar.h>
 #include <wctype.h>
 
-#include "chat.h"
+#include "edit.h"
+
+static bool isword(wchar_t ch) {
+	return !iswspace(ch) && !iswpunct(ch);
+}
 
-enum { Cap = 1024 };
-static wchar_t buf[Cap];
-static size_t len;
-static size_t pos;
+void editFree(struct Edit *e) {
+	free(e->buf);
+	free(e->cut.buf);
+	free(e->mbs.buf);
+	e->pos = e->len = e->cap = 0;
+	e->cut.len = 0;
+	e->mbs.pos = e->mbs.len = 0;
+}
 
-char *editBuffer(size_t *mbsPos) {
-	static char mbs[MB_LEN_MAX * Cap];
+char *editString(struct Edit *e) {
+	size_t cap = e->len * MB_CUR_MAX + 1;
+	char *buf = realloc(e->mbs.buf, cap);
+	if (!buf) return NULL;
+	e->mbs.buf = buf;
 
-	const wchar_t *ptr = buf;
-	size_t mbsLen = wcsnrtombs(mbs, &ptr, pos, sizeof(mbs) - 1, NULL);
-	assert(mbsLen != (size_t)-1);
-	if (mbsPos) *mbsPos = mbsLen;
+	const wchar_t *ptr = e->buf;
+	e->mbs.len = wcsnrtombs(e->mbs.buf, &ptr, e->pos, cap-1, NULL);
+	if (e->mbs.len == (size_t)-1) return NULL;
+	e->mbs.pos = e->mbs.len;
 
-	ptr = &buf[pos];
+	ptr = &e->buf[e->pos];
 	size_t n = wcsnrtombs(
-		&mbs[mbsLen], &ptr, len - pos, sizeof(mbs) - mbsLen - 1, NULL
+		&e->mbs.buf[e->mbs.len], &ptr, e->len - e->pos,
+		cap-1 - e->mbs.len, NULL
 	);
-	assert(n != (size_t)-1);
-	mbsLen += n;
-
-	mbs[mbsLen] = '\0';
-	return mbs;
-}
-
-static struct {
-	wchar_t buf[Cap];
-	size_t len;
-} cut;
+	if (n == (size_t)-1) return NULL;
+	e->mbs.len += n;
 
-static bool reserve(size_t index, size_t count) {
-	if (len + count > Cap) return false;
-	wmemmove(&buf[index + count], &buf[index], len - index);
-	len += count;
-	return true;
+	e->mbs.buf[e->mbs.len] = '\0';
+	return e->mbs.buf;
 }
 
-static void delete(bool copy, size_t index, size_t count) {
-	if (index + count > len) return;
-	if (copy) {
-		wmemcpy(cut.buf, &buf[index], count);
-		cut.len = count;
+int editReserve(struct Edit *e, size_t index, size_t count) {
+	if (index > e->len) {
+		errno = EINVAL;
+		return -1;
 	}
-	wmemmove(&buf[index], &buf[index + count], len - index - count);
-	len -= count;
-}
-
-static const struct {
-	const wchar_t *name;
-	const wchar_t *string;
-} Macros[] = {
-	{ L"\\banhammer", L"▬▬▬▬▬▬▬▋ Ò╭╮Ó" },
-	{ L"\\bear", L"ʕっ•ᴥ•ʔっ" },
-	{ L"\\blush", L"（˶′◡‵˶）" },
-	{ L"\\com", L"\0038,4\2 ☭ " },
-	{ L"\\cool", L"(⌐■_■)" },
-	{ L"\\flip", L"(╯°□°）╯︵ ┻━┻" },
-	{ L"\\gary", L"ᕕ( ᐛ )ᕗ" },
-	{ L"\\hug", L"（っ・∀・）っ" },
-	{ L"\\lenny", L"( ͡° ͜ʖ ͡°)" },
-	{ L"\\look", L"ಠ_ಠ" },
-	{ L"\\shrug", L"¯\\_(ツ)_/¯" },
-	{ L"\\unflip", L"┬─┬ノ(º_ºノ)" },
-	{ L"\\wave", L"ヾ(＾∇＾)" },
-};
-
-void editCompleteAdd(void) {
-	char mbs[256];
-	for (size_t i = 0; i < ARRAY_LEN(Macros); ++i) {
-		size_t n = wcstombs(mbs, Macros[i].name, sizeof(mbs));
-		assert(n != (size_t)-1);
-		completeAdd(None, mbs, Default);
+	if (e->len + count > e->cap) {
+		size_t cap = (e->cap ? e->cap * 2 : 256);
+		wchar_t *buf = realloc(e->buf, sizeof(*buf) * cap);
+		if (!buf) return -1;
+		e->buf = buf;
+		e->cap = cap;
 	}
+	wmemmove(&e->buf[index + count], &e->buf[index], e->len - index);
+	e->len += count;
+	return 0;
 }
 
-static void macroExpand(void) {
-	size_t macro = pos;
-	while (macro && buf[macro] != L'\\') macro--;
-	if (macro == pos) return;
-	for (size_t i = 0; i < ARRAY_LEN(Macros); ++i) {
-		if (wcsncmp(Macros[i].name, &buf[macro], pos - macro)) continue;
-		if (wcstombs(NULL, Macros[i].string, 0) == (size_t)-1) continue;
-		delete(false, macro, pos - macro);
-		pos = macro;
-		size_t expand = wcslen(Macros[i].string);
-		if (reserve(macro, expand)) {
-			wcsncpy(&buf[macro], Macros[i].string, expand);
-			pos += expand;
-		}
+int editCopy(struct Edit *e, size_t index, size_t count) {
+	if (index + count > e->len) {
+		errno = EINVAL;
+		return -1;
 	}
+	wchar_t *buf = realloc(e->cut.buf, sizeof(*buf) * count);
+	if (!buf) return -1;
+	e->cut.buf = buf;
+	wmemcpy(e->cut.buf, &e->buf[index], count);
+	e->cut.len = count;
+	return 0;
 }
 
-static struct {
-	size_t pos;
-	size_t pre;
-	size_t len;
-	bool suffix;
-} tab;
-
-static void tabComplete(uint id) {
-	if (!tab.len) {
-		tab.pos = pos;
-		while (tab.pos && !iswspace(buf[tab.pos - 1])) tab.pos--;
-		if (tab.pos == pos) return;
-		tab.pre = pos - tab.pos;
-		tab.len = tab.pre;
-		tab.suffix = true;
-	}
-
-	char mbs[MB_LEN_MAX * Cap];
-	const wchar_t *ptr = &buf[tab.pos];
-	size_t n = wcsnrtombs(mbs, &ptr, tab.pre, sizeof(mbs) - 1, NULL);
-	assert(n != (size_t)-1);
-	mbs[n] = '\0';
-
-	const char *comp = complete(id, mbs);
-	if (!comp) {
-		comp = complete(id, mbs);
-		tab.suffix ^= true;
-	}
-	if (!comp) {
-		tab.len = 0;
-		return;
-	}
-
-	wchar_t wcs[Cap];
-	n = mbstowcs(wcs, comp, Cap);
-	assert(n != (size_t)-1);
-	if (tab.pos + n + 2 > Cap) {
-		completeReject();
-		tab.len = 0;
-		return;
-	}
-
-	bool colon = (tab.len >= 2 && buf[tab.pos + tab.len - 2] == L':');
-
-	delete(false, tab.pos, tab.len);
-	tab.len = n;
-	if (wcs[0] == L'\\' || wcschr(wcs, L' ')) {
-		reserve(tab.pos, tab.len);
-	} else if (wcs[0] != L'/' && tab.suffix && (!tab.pos || colon)) {
-		tab.len += 2;
-		reserve(tab.pos, tab.len);
-		buf[tab.pos + n + 0] = L':';
-		buf[tab.pos + n + 1] = L' ';
-	} else if (tab.suffix && tab.pos >= 2 && buf[tab.pos - 2] == L':') {
-		tab.len += 2;
-		reserve(tab.pos, tab.len);
-		buf[tab.pos - 2] = L',';
-		buf[tab.pos + n + 0] = L':';
-		buf[tab.pos + n + 1] = L' ';
-	} else {
-		tab.len++;
-		reserve(tab.pos, tab.len);
-		if (!tab.suffix && tab.pos >= 2 && buf[tab.pos - 2] == L',') {
-			buf[tab.pos - 2] = L':';
-		}
-		buf[tab.pos + n] = L' ';
+int editDelete(struct Edit *e, bool cut, size_t index, size_t count) {
+	if (index + count > e->len) {
+		errno = EINVAL;
+		return -1;
 	}
-	wmemcpy(&buf[tab.pos], wcs, n);
-	pos = tab.pos + tab.len;
-}
-
-static void tabAccept(void) {
-	completeAccept();
-	tab.len = 0;
-}
-
-static void tabReject(void) {
-	completeReject();
-	tab.len = 0;
-}
-
-static bool isword(wchar_t ch) {
-	return !iswspace(ch) && !iswpunct(ch);
+	if (cut && editCopy(e, index, count) < 0) return -1;
+	wmemmove(&e->buf[index], &e->buf[index + count], e->len - index - count);
+	e->len -= count;
+	if (e->pos > e->len) e->pos = e->len;
+	return 0;
 }
 
-void edit(uint id, enum Edit op, wchar_t ch) {
-	size_t init = pos;
-	switch (op) {
-		break; case EditHead: pos = 0;
-		break; case EditTail: pos = len;
-		break; case EditPrev: if (pos) pos--;
-		break; case EditNext: if (pos < len) pos++;
+int editFn(struct Edit *e, enum EditFn fn) {
+	int ret = 0;
+	switch (fn) {
+		break; case EditHead: e->pos = 0;
+		break; case EditTail: e->pos = e->len;
+		break; case EditPrev: if (e->pos) e->pos--;
+		break; case EditNext: if (e->pos < e->len) e->pos++;
 		break; case EditPrevWord: {
-			while (pos && !isword(buf[pos - 1])) pos--;
-			while (pos && isword(buf[pos - 1])) pos--;
+			while (e->pos && !isword(e->buf[e->pos-1])) e->pos--;
+			while (e->pos && isword(e->buf[e->pos-1])) e->pos--;
 		}
 		break; case EditNextWord: {
-			while (pos < len && isword(buf[pos])) pos++;
-			while (pos < len && !isword(buf[pos])) pos++;
+			while (e->pos < e->len && isword(e->buf[e->pos])) e->pos++;
+			while (e->pos < e->len && !isword(e->buf[e->pos])) e->pos++;
 		}
 
-		break; case EditDeleteHead: delete(true, 0, pos); pos = 0;
-		break; case EditDeleteTail: delete(true, pos, len - pos);
-		break; case EditDeletePrev: if (pos) delete(false, --pos, 1);
-		break; case EditDeleteNext: delete(false, pos, 1);
+		break; case EditDeleteHead: {
+			ret = editDelete(e, true, 0, e->pos);
+			e->pos = 0;
+		}
+		break; case EditDeleteTail: {
+			ret = editDelete(e, true, e->pos, e->len - e->pos);
+		}
+		break; case EditDeletePrev: {
+			if (e->pos) editDelete(e, false, --e->pos, 1);
+		}
+		break; case EditDeleteNext: {
+			editDelete(e, false, e->pos, 1);
+		}
 		break; case EditDeletePrevWord: {
-			if (!pos) break;
-			size_t word = pos;
-			while (word && !isword(buf[word - 1])) word--;
-			while (word && isword(buf[word - 1])) word--;
-			delete(true, word, pos - word);
-			pos = word;
+			if (!e->pos) break;
+			size_t word = e->pos;
+			while (word && !isword(e->buf[word-1])) word--;
+			while (word && isword(e->buf[word-1])) word--;
+			ret = editDelete(e, true, word, e->pos - word);
+			e->pos = word;
 		}
 		break; case EditDeleteNextWord: {
-			if (pos == len) break;
-			size_t word = pos;
-			while (word < len && !isword(buf[word])) word++;
-			while (word < len && isword(buf[word])) word++;
-			delete(true, pos, word - pos);
+			if (e->pos == e->len) break;
+			size_t word = e->pos;
+			while (word < e->len && !isword(e->buf[word])) word++;
+			while (word < e->len && isword(e->buf[word])) word++;
+			ret = editDelete(e, true, e->pos, word - e->pos);
 		}
+
 		break; case EditPaste: {
-			if (reserve(pos, cut.len)) {
-				wmemcpy(&buf[pos], cut.buf, cut.len);
-				pos += cut.len;
+			ret = editReserve(e, e->pos, e->cut.len);
+			if (ret == 0) {
+				wmemcpy(&e->buf[e->pos], e->cut.buf, e->cut.len);
+				e->pos += e->cut.len;
 			}
 		}
-
 		break; case EditTranspose: {
-			if (!pos || len < 2) break;
-			if (pos == len) pos--;
-			wchar_t t = buf[pos - 1];
-			buf[pos - 1] = buf[pos];
-			buf[pos++] = t;
+			if (e->len < 2) break;
+			if (!e->pos) e->pos++;
+			if (e->pos == e->len) e->pos--;
+			wchar_t x = e->buf[e->pos-1];
+			e->buf[e->pos-1] = e->buf[e->pos];
+			e->buf[e->pos++] = x;
 		}
 		break; case EditCollapse: {
 			size_t ws;
-			for (pos = 0; pos < len;) {
-				for (; pos < len && !iswspace(buf[pos]); ++pos);
-				for (ws = pos; ws < len && iswspace(buf[ws]); ++ws);
-				if (pos && ws < len) {
-					delete(false, pos, ws - pos - 1);
-					buf[pos++] = L' ';
+			for (e->pos = 0; e->pos < e->len;) {
+				for (; e->pos < e->len && !iswspace(e->buf[e->pos]); ++e->pos);
+				for (ws = e->pos; ws < e->len && iswspace(e->buf[ws]); ++ws);
+				if (e->pos && ws < e->len) {
+					editDelete(e, false, e->pos, ws - e->pos - 1);
+					e->buf[e->pos++] = L' ';
 				} else {
-					delete(false, pos, ws - pos);
+					editDelete(e, false, e->pos, ws - e->pos);
 				}
 			}
 		}
 
-		break; case EditInsert: {
-			char mb[MB_LEN_MAX];
-			if (wctomb(mb, ch) < 0) return;
-			if (reserve(pos, 1)) {
-				buf[pos++] = ch;
-			}
-		}
-		break; case EditComplete: {
-			tabComplete(id);
-			return;
-		}
-		break; case EditExpand: {
-			macroExpand();
-			tabAccept();
-			return;
-		}
-		break; case EditEnter: {
-			tabAccept();
-			command(id, editBuffer(NULL));
-			len = pos = 0;
-			return;
-		}
+		break; case EditClear: e->len = e->pos = 0;
 	}
+	return ret;
+}
+
+int editInsert(struct Edit *e, wchar_t ch) {
+	char mb[MB_LEN_MAX];
+	if (wctomb(mb, ch) < 0) return -1;
+	if (editReserve(e, e->pos, 1) < 0) return -1;
+	e->buf[e->pos++] = ch;
+	return 0;
+}
+
+#ifdef TEST
+#undef NDEBUG
+#include <assert.h>
+#include <string.h>
 
-	if (pos < init) {
-		tabReject();
-	} else {
-		tabAccept();
+static void fix(struct Edit *e, const char *str) {
+	editFn(e, EditClear);
+	for (const char *ch = str; *ch; ++ch) {
+		editInsert(e, (wchar_t)*ch);
 	}
 }
+
+static bool eq(struct Edit *e, const char *str1) {
+	const char *str2 = &str1[strlen(str1) + 1];
+	const char *buf = editString(e);
+	return e->mbs.pos == strlen(str1)
+		&& !strncmp(buf, str1, e->mbs.pos)
+		&& !strcmp(&buf[e->mbs.pos], str2);
+}
+
+int main(void) {
+	struct Edit e = { .mode = EditEmacs };
+
+	fix(&e, "foo bar");
+	editFn(&e, EditHead);
+	assert(eq(&e, "\0foo bar"));
+	editFn(&e, EditTail);
+	assert(eq(&e, "foo bar\0"));
+	editFn(&e, EditPrev);
+	assert(eq(&e, "foo ba\0r"));
+	editFn(&e, EditNext);
+	assert(eq(&e, "foo bar\0"));
+
+	fix(&e, "foo, bar");
+	editFn(&e, EditPrevWord);
+	assert(eq(&e, "foo, \0bar"));
+	editFn(&e, EditPrevWord);
+	assert(eq(&e, "\0foo, bar"));
+	editFn(&e, EditNextWord);
+	assert(eq(&e, "foo, \0bar"));
+	editFn(&e, EditNextWord);
+	assert(eq(&e, "foo, bar\0"));
+
+	fix(&e, "foo bar");
+	editFn(&e, EditPrevWord);
+	editFn(&e, EditDeleteHead);
+	assert(eq(&e, "\0bar"));
+
+	fix(&e, "foo bar");
+	editFn(&e, EditPrevWord);
+	editFn(&e, EditDeleteTail);
+	assert(eq(&e, "foo \0"));
+
+	fix(&e, "foo bar");
+	editFn(&e, EditDeletePrev);
+	assert(eq(&e, "foo ba\0"));
+	editFn(&e, EditHead);
+	editFn(&e, EditDeleteNext);
+	assert(eq(&e, "\0oo ba"));
+
+	fix(&e, "foo, bar");
+	editFn(&e, EditDeletePrevWord);
+	assert(eq(&e, "foo, \0"));
+	editFn(&e, EditDeletePrevWord);
+	assert(eq(&e, "\0"));
+
+	fix(&e, "foo, bar");
+	editFn(&e, EditHead);
+	editFn(&e, EditDeleteNextWord);
+	assert(eq(&e, "\0, bar"));
+	editFn(&e, EditDeleteNextWord);
+	assert(eq(&e, "\0"));
+
+	fix(&e, "foo bar");
+	editFn(&e, EditDeletePrevWord);
+	editFn(&e, EditPaste);
+	assert(eq(&e, "foo bar\0"));
+	editFn(&e, EditPaste);
+	assert(eq(&e, "foo barbar\0"));
+
+	fix(&e, "bar");
+	editFn(&e, EditTranspose);
+	assert(eq(&e, "bra\0"));
+	editFn(&e, EditHead);
+	editFn(&e, EditTranspose);
+	assert(eq(&e, "rb\0a"));
+	editFn(&e, EditTranspose);
+	assert(eq(&e, "rab\0"));
+
+	fix(&e, "  foo  bar  ");
+	editFn(&e, EditCollapse);
+	assert(eq(&e, "foo bar\0"));
+}
+
+#endif /* TEST */