1 /* notmuch - Not much of an email program, (just index and search)
2 *
3 * Copyright © 2012 Peter Feigl
4 *
5 * This program is free software: you can redistribute it and/or modify
6 * it under the terms of the GNU General Public License as published by
7 * the Free Software Foundation, either version 3 of the License, or
8 * (at your option) any later version.
9 *
10 * This program is distributed in the hope that it will be useful,
11 * but WITHOUT ANY WARRANTY; without even the implied warranty of
12 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
13 * GNU General Public License for more details.
14 *
15 * You should have received a copy of the GNU General Public License
16 * along with this program. If not, see https://www.gnu.org/licenses/ .
17 *
18 * Author: Peter Feigl <peter.feigl@gmx.at>
19 */
20
21 #include <inttypes.h>
22 #include <stdbool.h>
23 #include <stdio.h>
24 #include <talloc.h>
25 #include "sprinter.h"
26 #include <ctype.h>
27
28 struct sprinter_sexp {
29 struct sprinter vtable;
30 FILE *stream;
31 /* Top of the state stack, or NULL if the printer is not currently
32 * inside any aggregate types. */
33 struct sexp_state *state;
34
35 /* A flag to signify that a separator should be inserted in the
36 * output as soon as possible. */
37 bool insert_separator;
38 };
39
40 struct sexp_state {
41 struct sexp_state *parent;
42
43 /* True if nothing has been printed in this aggregate yet.
44 * Suppresses the space before a value. */
45 bool first;
46 };
47
48 /* Helper function to set up the stream to print a value. If this
49 * value follows another value, prints a space. */
50 static struct sprinter_sexp *
sexp_begin_value(struct sprinter * sp)51 sexp_begin_value (struct sprinter *sp)
52 {
53 struct sprinter_sexp *sps = (struct sprinter_sexp *) sp;
54
55 if (sps->state) {
56 if (! sps->state->first) {
57 if (sps->insert_separator) {
58 fputc ('\n', sps->stream);
59 sps->insert_separator = false;
60 } else {
61 fputc (' ', sps->stream);
62 }
63 } else {
64 sps->state->first = false;
65 }
66 }
67 return sps;
68 }
69
70 /* Helper function to begin an aggregate type. Prints the open
71 * character and pushes a new state frame. */
72 static void
sexp_begin_aggregate(struct sprinter * sp)73 sexp_begin_aggregate (struct sprinter *sp)
74 {
75 struct sprinter_sexp *sps = sexp_begin_value (sp);
76 struct sexp_state *state = talloc (sps, struct sexp_state);
77
78 fputc ('(', sps->stream);
79 state->parent = sps->state;
80 state->first = true;
81 sps->state = state;
82 }
83
84 static void
sexp_begin_map(struct sprinter * sp)85 sexp_begin_map (struct sprinter *sp)
86 {
87 sexp_begin_aggregate (sp);
88 }
89
90 static void
sexp_begin_list(struct sprinter * sp)91 sexp_begin_list (struct sprinter *sp)
92 {
93 sexp_begin_aggregate (sp);
94 }
95
96 static void
sexp_end(struct sprinter * sp)97 sexp_end (struct sprinter *sp)
98 {
99 struct sprinter_sexp *sps = (struct sprinter_sexp *) sp;
100 struct sexp_state *state = sps->state;
101
102 fputc (')', sps->stream);
103 sps->state = state->parent;
104 talloc_free (state);
105 if (sps->state == NULL)
106 fputc ('\n', sps->stream);
107 }
108
109 static void
sexp_string_len(struct sprinter * sp,const char * val,size_t len)110 sexp_string_len (struct sprinter *sp, const char *val, size_t len)
111 {
112 /* Some characters need escaping. " and \ work fine in all Lisps,
113 * \n is not supported in CL, but all others work fine.
114 * Characters below 32 are printed as \123o (three-digit
115 * octals), which work fine in most Schemes and Emacs. */
116 static const char *const escapes[] = {
117 ['\"'] = "\\\"", ['\\'] = "\\\\", ['\n'] = "\\n"
118 };
119 struct sprinter_sexp *sps = sexp_begin_value (sp);
120
121 fputc ('"', sps->stream);
122 for (; len; ++val, --len) {
123 unsigned char ch = *val;
124 if (ch < ARRAY_SIZE (escapes) && escapes[ch])
125 fputs (escapes[ch], sps->stream);
126 else if (ch >= 32)
127 fputc (ch, sps->stream);
128 else
129 fprintf (sps->stream, "\\%03o", ch);
130 }
131 fputc ('"', sps->stream);
132 }
133
134 static void
sexp_string(struct sprinter * sp,const char * val)135 sexp_string (struct sprinter *sp, const char *val)
136 {
137 if (val == NULL)
138 val = "";
139 sexp_string_len (sp, val, strlen (val));
140 }
141
142 /* Prints a symbol, i.e. the name preceded by a colon. This should work
143 * in all Lisps, at least as a symbol, if not as a proper keyword */
144 static void
sexp_keyword(struct sprinter * sp,const char * val)145 sexp_keyword (struct sprinter *sp, const char *val)
146 {
147 unsigned int i = 0;
148 struct sprinter_sexp *sps = (struct sprinter_sexp *) sp;
149 char ch;
150
151 if (val == NULL)
152 INTERNAL_ERROR ("illegal symbol NULL");
153
154 for (i = 0; i < strlen (val); i++) {
155 ch = val[i];
156 if (! (isalnum (ch) || (ch == '-') || (ch == '_'))) {
157 INTERNAL_ERROR ("illegal character in symbol %s: %c", val, ch);
158 }
159 }
160 fputc (':', sps->stream);
161 fputs (val, sps->stream);
162 }
163
164 static void
sexp_integer(struct sprinter * sp,int64_t val)165 sexp_integer (struct sprinter *sp, int64_t val)
166 {
167 struct sprinter_sexp *sps = sexp_begin_value (sp);
168
169 fprintf (sps->stream, "%" PRId64, val);
170 }
171
172 static void
sexp_boolean(struct sprinter * sp,bool val)173 sexp_boolean (struct sprinter *sp, bool val)
174 {
175 struct sprinter_sexp *sps = sexp_begin_value (sp);
176
177 fputs (val ? "t" : "nil", sps->stream);
178 }
179
180 static void
sexp_null(struct sprinter * sp)181 sexp_null (struct sprinter *sp)
182 {
183 struct sprinter_sexp *sps = sexp_begin_value (sp);
184
185 fputs ("nil", sps->stream);
186 }
187
188 static void
sexp_map_key(struct sprinter * sp,const char * key)189 sexp_map_key (struct sprinter *sp, const char *key)
190 {
191 sexp_begin_value (sp);
192
193 sexp_keyword (sp, key);
194 }
195
196 static void
sexp_set_prefix(unused (struct sprinter * sp),unused (const char * name))197 sexp_set_prefix (unused (struct sprinter *sp), unused (const char *name))
198 {
199 }
200
201 static void
sexp_separator(struct sprinter * sp)202 sexp_separator (struct sprinter *sp)
203 {
204 struct sprinter_sexp *sps = (struct sprinter_sexp *) sp;
205
206 sps->insert_separator = true;
207 }
208
209 struct sprinter *
sprinter_sexp_create(const void * ctx,FILE * stream)210 sprinter_sexp_create (const void *ctx, FILE *stream)
211 {
212 static const struct sprinter_sexp template = {
213 .vtable = {
214 .begin_map = sexp_begin_map,
215 .begin_list = sexp_begin_list,
216 .end = sexp_end,
217 .string = sexp_string,
218 .string_len = sexp_string_len,
219 .integer = sexp_integer,
220 .boolean = sexp_boolean,
221 .null = sexp_null,
222 .map_key = sexp_map_key,
223 .separator = sexp_separator,
224 .set_prefix = sexp_set_prefix,
225 .is_text_printer = false,
226 }
227 };
228 struct sprinter_sexp *res;
229
230 res = talloc (ctx, struct sprinter_sexp);
231 if (! res)
232 return NULL;
233
234 *res = template;
235 res->stream = stream;
236 return &res->vtable;
237 }
238