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->line);
68 		free(vl);
69 	}
70 }
71 
72 static int
73 push_line(struct buffer *buffer, struct line *l, const char *buf, size_t len, int flags)
74 {
75 	struct vline *vl;
76 	const char *end;
77 
78 	/* omit trailing spaces */
79 	if (len != 0) {
80 		for (end = buf + len - 1;
81 		     end > buf && isspace(*end);
82 		     end--, len--)
83 			;	/* nop */
84 	}
85 
86 	if (!(l->flags & L_HIDDEN))
87 		buffer->line_max++;
88 
89 	if ((vl = calloc(1, sizeof(*vl))) == NULL)
90 		return 0;
91 
92 	if (len != 0 && (vl->line = calloc(1, len+1)) == NULL) {
93 		free(vl);
94 		return 0;
95 	}
96 
97 	vl->parent = l;
98 	if (len != 0)
99 		memcpy(vl->line, buf, len);
100 	vl->flags = flags;
101 
102 	TAILQ_INSERT_TAIL(&buffer->head, vl, vlines);
103 	return 1;
104 }
105 
106 /*
107  * Build a list of visual line by wrapping the given line, assuming
108  * that when printed will have a leading prefix prfx.
109  */
110 int
111 wrap_text(struct buffer *buffer, const char *prfx, struct line *l,
112     size_t width, int oneline)
113 {
114 	const char	*line, *space;
115 	size_t		 ret, off, start, cur, prfxwidth;
116 	int		 flags;
117 
118 	if ((line = l->line) == NULL || *line == '\0')
119 		return push_line(buffer, l, NULL, 0, 0);
120 
121 	prfxwidth = utf8_swidth(prfx);
122 	cur = prfxwidth;
123 	start = 0;
124 	flags = 0;
125 
126 	if (l->type == LINE_LINK && emojify_link &&
127 	    emojied_line(l->line, &space)) {
128 		prfxwidth = utf8_swidth_between(l->line, space);
129 		cur = prfxwidth;
130 		line = space + 1;
131 	}
132 
133 	for (off = 0; line[off] != '\0'; off += ret) {
134 		size_t t;
135 
136 		ret = grapheme_next_line_break_utf8(&line[off], SIZE_MAX);
137 		t = utf8_swidth_between(&line[off], &line[off + ret]);
138 
139 		if (cur + t <= width) {
140 			cur += t;
141 			continue;
142 		}
143 
144 		if (!push_line(buffer, l, &line[start], off - start, flags))
145 			return 0;
146 
147 		if (oneline)
148 			return 0;
149 
150 		flags = L_CONTINUATION;
151 		start = off;
152 		cur = t;
153 	}
154 
155 	if (off != start)
156 		return push_line(buffer, l, &line[start], off - start, flags);
157 	return 0;
158 }
159 
160 int
161 wrap_page(struct buffer *buffer, int width)
162 {
163 	struct line		*l;
164 	const struct line	*top_orig, *orig;
165 	struct vline		*vl;
166 	const char		*prfx;
167 
168 	top_orig = buffer->top_line == NULL ? NULL : buffer->top_line->parent;
169 	orig = buffer->current_line == NULL ? NULL : buffer->current_line->parent;
170 
171 	buffer->top_line = NULL;
172 	buffer->current_line = NULL;
173 
174 	buffer->force_redraw = 1;
175 	buffer->curs_y = 0;
176 	buffer->line_off = 0;
177 
178 	empty_vlist(buffer);
179 
180 	TAILQ_FOREACH(l, &buffer->page.head, lines) {
181 		prfx = line_prefixes[l->type].prfx1;
182 		switch (l->type) {
183 		case LINE_TEXT:
184 		case LINE_LINK:
185 		case LINE_TITLE_1:
186 		case LINE_TITLE_2:
187 		case LINE_TITLE_3:
188 		case LINE_ITEM:
189 		case LINE_QUOTE:
190 		case LINE_PRE_START:
191 		case LINE_PRE_END:
192 		case LINE_PRE_CONTENT:
193 		case LINE_PATCH:
194 		case LINE_PATCH_HDR:
195 		case LINE_PATCH_HUNK_HDR:
196 		case LINE_PATCH_ADD:
197 		case LINE_PATCH_DEL:
198 			wrap_text(buffer, prfx, l, MIN(fill_column, width),
199 			    0);
200 			break;
201 		case LINE_COMPL:
202 		case LINE_COMPL_CURRENT:
203 		case LINE_HELP:
204 		case LINE_DOWNLOAD:
205 		case LINE_DOWNLOAD_DONE:
206 		case LINE_DOWNLOAD_INFO:
207 			wrap_text(buffer, prfx, l, width, 1);
208 			break;
209 		case LINE_FRINGE:
210 			/* never, ever wrapped */
211 			break;
212 		}
213 
214 		if (top_orig == l && buffer->top_line == NULL) {
215 			buffer->line_off = buffer->line_max-1;
216 			buffer->top_line = TAILQ_LAST(&buffer->head, vhead);
217 
218 			while (1) {
219 				vl = TAILQ_PREV(buffer->top_line, vhead, vlines);
220 				if (vl == NULL || vl->parent != orig)
221 					break;
222 				buffer->top_line = vl;
223 				buffer->line_off--;
224 			}
225 		}
226 
227 		if (orig == l && buffer->current_line == NULL) {
228 			buffer->current_line = TAILQ_LAST(&buffer->head, vhead);
229 
230 			while (1) {
231 				vl = TAILQ_PREV(buffer->current_line, vhead, vlines);
232 				if (vl == NULL || vl->parent != orig)
233 					break;
234 				buffer->current_line = vl;
235 			}
236 		}
237 	}
238 
239 	if (buffer->current_line == NULL)
240 		buffer->current_line = TAILQ_FIRST(&buffer->head);
241 
242 	if (buffer->top_line == NULL)
243 		buffer->top_line = buffer->current_line;
244 
245 	return 1;
246 }