1 /*
2  * Copyright (c) 2021 Omar Polo <op@omarpolo.com>
3  *
4  * Permission to use, copy, modify, and distribute this software for any
5  * purpose with or without fee is hereby granted, provided that the above
6  * copyright notice and this permission notice appear in all copies.
7  *
8  * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
9  * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
10  * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
11  * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
12  * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
13  * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
14  * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
15  */
16 
17 #include "compat.h"
18 
19 #include <ctype.h>
20 #include <stdint.h>
21 #include <stdlib.h>
22 #include <string.h>
23 
24 #include <grapheme.h>
25 
26 #include "defaults.h"
27 #include "telescope.h"
28 #include "utf8.h"
29 
30 void
31 erase_buffer(struct buffer *buffer)
32 {
33 	empty_vlist(buffer);
34 	empty_linelist(buffer);
35 }
36 
37 void
38 empty_linelist(struct buffer *buffer)
39 {
40 	struct line *l, *lt;
41 
42 	TAILQ_FOREACH_SAFE(l, &buffer->page.head, lines, lt) {
43 		TAILQ_REMOVE(&buffer->page.head, l, lines);
44 		free(l->line);
45 
46 		if (l->type != LINE_COMPL &&
47 		    l->type != LINE_COMPL_CURRENT &&
48 		    l->type != LINE_HELP)
49 			free(l->alt);
50 
51 		free(l);
52 	}
53 }
54 
55 void
56 empty_vlist(struct buffer *buffer)
57 {
58 	struct vline *vl, *t;
59 
60 	buffer->top_line = NULL;
61 	buffer->line_off = 0;
62 	buffer->current_line = NULL;
63 	buffer->line_max = 0;
64 
65 	TAILQ_FOREACH_SAFE(vl, &buffer->head, vlines, t) {
66 		TAILQ_REMOVE(&buffer->head, vl, vlines);
67 		free(vl);
68 	}
69 }
70 
71 static int
72 push_line(struct buffer *buffer, struct line *l, const char *buf, size_t len, int flags)
73 {
74 	struct vline *vl;
75 	const char *end;
76 
77 	/* omit trailing spaces */
78 	if (len != 0) {
79 		for (end = buf + len - 1;
80 		     end > buf && isspace(*end);
81 		     end--, len--)
82 			;	/* nop */
83 	}
84 
85 	if (!(l->flags & L_HIDDEN))
86 		buffer->line_max++;
87 
88 	if ((vl = calloc(1, sizeof(*vl))) == NULL)
89 		return 0;
90 
91 	vl->parent = l;
92 	if (len != 0) {
93 		vl->from = buf - l->line;
94 		vl->len = len;
95 		vl->cplen = utf8_ncplen(buf, vl->len);
96 	}
97 	vl->flags = flags;
98 
99 	TAILQ_INSERT_TAIL(&buffer->head, vl, vlines);
100 	return 1;
101 }
102 
103 /*
104  * Build a list of visual line by wrapping the given line, assuming
105  * that when printed will have a leading prefix prfx.
106  */
107 int
108 wrap_text(struct buffer *buffer, const char *prfx, struct line *l,
109     size_t width, int oneline)
110 {
111 	const char	*line, *space;
112 	size_t		 ret, off, start, cur, prfxwidth;
113 	int		 flags;
114 
115 	if ((line = l->line) == NULL || *line == '\0')
116 		return push_line(buffer, l, NULL, 0, 0);
117 
118 	prfxwidth = utf8_swidth(prfx);
119 	cur = prfxwidth;
120 	start = 0;
121 	flags = 0;
122 
123 	if (l->type == LINE_LINK && emojify_link &&
124 	    emojied_line(l->line, &space)) {
125 	    	prfxwidth = utf8_swidth_between(l->line, space);
126 		cur = prfxwidth;
127 		line = space + 1;
128 	}
129 
130 	for (off = 0; line[off] != '\0'; off += ret) {
131 		size_t t;
132 
133 		ret = grapheme_next_line_break_utf8(&line[off], SIZE_MAX);
134 		t = utf8_swidth_between(&line[off], &line[off + ret]);
135 
136 		if (cur + t <= width) {
137 			cur += t;
138 			continue;
139 		}
140 
141 		if (!push_line(buffer, l, &line[start], off - start, flags))
142 			return 0;
143 
144 		if (oneline)
145 			return 0;
146 
147 		flags = L_CONTINUATION;
148 		start = off;
149 		cur = t + prfxwidth;
150 	}
151 
152 	if (off != start)
153 		return push_line(buffer, l, &line[start], off - start, flags);
154 	return 0;
155 }
156 
157 int
158 wrap_page(struct buffer *buffer, int width)
159 {
160 	struct line		*l;
161 	const struct line	*top_orig, *orig;
162 	struct vline		*vl;
163 	const char		*prfx;
164 
165 	top_orig = buffer->top_line == NULL ? NULL : buffer->top_line->parent;
166 	orig = buffer->current_line == NULL ? NULL : buffer->current_line->parent;
167 
168 	buffer->top_line = NULL;
169 	buffer->current_line = NULL;
170 
171 	buffer->force_redraw = 1;
172 	buffer->curs_y = 0;
173 	buffer->line_off = 0;
174 
175 	empty_vlist(buffer);
176 
177 	TAILQ_FOREACH(l, &buffer->page.head, lines) {
178 		prfx = line_prefixes[l->type].prfx1;
179 		switch (l->type) {
180 		case LINE_TEXT:
181 		case LINE_LINK:
182 		case LINE_TITLE_1:
183 		case LINE_TITLE_2:
184 		case LINE_TITLE_3:
185 		case LINE_ITEM:
186 		case LINE_QUOTE:
187 		case LINE_PRE_START:
188 		case LINE_PRE_END:
189 		case LINE_PRE_CONTENT:
190 		case LINE_PATCH:
191 		case LINE_PATCH_HDR:
192 		case LINE_PATCH_HUNK_HDR:
193 		case LINE_PATCH_ADD:
194 		case LINE_PATCH_DEL:
195 			wrap_text(buffer, prfx, l, MIN(fill_column, width),
196 			    0);
197 			break;
198 		case LINE_COMPL:
199 		case LINE_COMPL_CURRENT:
200 		case LINE_HELP:
201 		case LINE_DOWNLOAD:
202 		case LINE_DOWNLOAD_DONE:
203 		case LINE_DOWNLOAD_INFO:
204 			wrap_text(buffer, prfx, l, width, 1);
205 			break;
206 		case LINE_FRINGE:
207 			/* never, ever wrapped */
208 			break;
209 		}
210 
211 		if (top_orig == l && buffer->top_line == NULL) {
212 			buffer->line_off = buffer->line_max-1;
213 			buffer->top_line = TAILQ_LAST(&buffer->head, vhead);
214 
215 			while (1) {
216 				vl = TAILQ_PREV(buffer->top_line, vhead, vlines);
217 				if (vl == NULL || vl->parent != orig)
218 					break;
219 				buffer->top_line = vl;
220 				buffer->line_off--;
221 			}
222 		}
223 
224 		if (orig == l && buffer->current_line == NULL) {
225 			buffer->current_line = TAILQ_LAST(&buffer->head, vhead);
226 
227 			while (1) {
228 				vl = TAILQ_PREV(buffer->current_line, vhead, vlines);
229 				if (vl == NULL || vl->parent != orig)
230 					break;
231 				buffer->current_line = vl;
232 			}
233 		}
234 	}
235 
236 	if (buffer->current_line == NULL)
237 		buffer->current_line = TAILQ_FIRST(&buffer->head);
238 
239 	if (buffer->top_line == NULL)
240 		buffer->top_line = buffer->current_line;
241 
242 	return 1;
243 }