checkout: remove duplicate code
[git] / ws.c
1 /*
2  * Whitespace rules
3  *
4  * Copyright (c) 2007 Junio C Hamano
5  */
6 #include "cache.h"
7 #include "attr.h"
8
9 static struct whitespace_rule {
10         const char *rule_name;
11         unsigned rule_bits;
12         unsigned loosens_error:1,
13                 exclude_default:1;
14 } whitespace_rule_names[] = {
15         { "trailing-space", WS_TRAILING_SPACE, 0 },
16         { "space-before-tab", WS_SPACE_BEFORE_TAB, 0 },
17         { "indent-with-non-tab", WS_INDENT_WITH_NON_TAB, 0 },
18         { "cr-at-eol", WS_CR_AT_EOL, 1 },
19         { "blank-at-eol", WS_BLANK_AT_EOL, 0 },
20         { "blank-at-eof", WS_BLANK_AT_EOF, 0 },
21         { "tab-in-indent", WS_TAB_IN_INDENT, 0, 1 },
22 };
23
24 unsigned parse_whitespace_rule(const char *string)
25 {
26         unsigned rule = WS_DEFAULT_RULE;
27
28         while (string) {
29                 int i;
30                 size_t len;
31                 const char *ep;
32                 int negated = 0;
33
34                 string = string + strspn(string, ", \t\n\r");
35                 ep = strchrnul(string, ',');
36                 len = ep - string;
37
38                 if (*string == '-') {
39                         negated = 1;
40                         string++;
41                         len--;
42                 }
43                 if (!len)
44                         break;
45                 for (i = 0; i < ARRAY_SIZE(whitespace_rule_names); i++) {
46                         if (strncmp(whitespace_rule_names[i].rule_name,
47                                     string, len))
48                                 continue;
49                         if (negated)
50                                 rule &= ~whitespace_rule_names[i].rule_bits;
51                         else
52                                 rule |= whitespace_rule_names[i].rule_bits;
53                         break;
54                 }
55                 if (strncmp(string, "tabwidth=", 9) == 0) {
56                         unsigned tabwidth = atoi(string + 9);
57                         if (0 < tabwidth && tabwidth < 0100) {
58                                 rule &= ~WS_TAB_WIDTH_MASK;
59                                 rule |= tabwidth;
60                         }
61                         else
62                                 warning("tabwidth %.*s out of range",
63                                         (int)(len - 9), string + 9);
64                 }
65                 string = ep;
66         }
67
68         if (rule & WS_TAB_IN_INDENT && rule & WS_INDENT_WITH_NON_TAB)
69                 die("cannot enforce both tab-in-indent and indent-with-non-tab");
70         return rule;
71 }
72
73 unsigned whitespace_rule(struct index_state *istate, const char *pathname)
74 {
75         static struct attr_check *attr_whitespace_rule;
76         const char *value;
77
78         if (!attr_whitespace_rule)
79                 attr_whitespace_rule = attr_check_initl("whitespace", NULL);
80
81         git_check_attr(istate, pathname, attr_whitespace_rule);
82         value = attr_whitespace_rule->items[0].value;
83         if (ATTR_TRUE(value)) {
84                 /* true (whitespace) */
85                 unsigned all_rule = ws_tab_width(whitespace_rule_cfg);
86                 int i;
87                 for (i = 0; i < ARRAY_SIZE(whitespace_rule_names); i++)
88                         if (!whitespace_rule_names[i].loosens_error &&
89                             !whitespace_rule_names[i].exclude_default)
90                                 all_rule |= whitespace_rule_names[i].rule_bits;
91                 return all_rule;
92         } else if (ATTR_FALSE(value)) {
93                 /* false (-whitespace) */
94                 return ws_tab_width(whitespace_rule_cfg);
95         } else if (ATTR_UNSET(value)) {
96                 /* reset to default (!whitespace) */
97                 return whitespace_rule_cfg;
98         } else {
99                 /* string */
100                 return parse_whitespace_rule(value);
101         }
102 }
103
104 /* The returned string should be freed by the caller. */
105 char *whitespace_error_string(unsigned ws)
106 {
107         struct strbuf err = STRBUF_INIT;
108         if ((ws & WS_TRAILING_SPACE) == WS_TRAILING_SPACE)
109                 strbuf_addstr(&err, "trailing whitespace");
110         else {
111                 if (ws & WS_BLANK_AT_EOL)
112                         strbuf_addstr(&err, "trailing whitespace");
113                 if (ws & WS_BLANK_AT_EOF) {
114                         if (err.len)
115                                 strbuf_addstr(&err, ", ");
116                         strbuf_addstr(&err, "new blank line at EOF");
117                 }
118         }
119         if (ws & WS_SPACE_BEFORE_TAB) {
120                 if (err.len)
121                         strbuf_addstr(&err, ", ");
122                 strbuf_addstr(&err, "space before tab in indent");
123         }
124         if (ws & WS_INDENT_WITH_NON_TAB) {
125                 if (err.len)
126                         strbuf_addstr(&err, ", ");
127                 strbuf_addstr(&err, "indent with spaces");
128         }
129         if (ws & WS_TAB_IN_INDENT) {
130                 if (err.len)
131                         strbuf_addstr(&err, ", ");
132                 strbuf_addstr(&err, "tab in indent");
133         }
134         return strbuf_detach(&err, NULL);
135 }
136
137 /* If stream is non-NULL, emits the line after checking. */
138 static unsigned ws_check_emit_1(const char *line, int len, unsigned ws_rule,
139                                 FILE *stream, const char *set,
140                                 const char *reset, const char *ws)
141 {
142         unsigned result = 0;
143         int written = 0;
144         int trailing_whitespace = -1;
145         int trailing_newline = 0;
146         int trailing_carriage_return = 0;
147         int i;
148
149         /* Logic is simpler if we temporarily ignore the trailing newline. */
150         if (len > 0 && line[len - 1] == '\n') {
151                 trailing_newline = 1;
152                 len--;
153         }
154         if ((ws_rule & WS_CR_AT_EOL) &&
155             len > 0 && line[len - 1] == '\r') {
156                 trailing_carriage_return = 1;
157                 len--;
158         }
159
160         /* Check for trailing whitespace. */
161         if (ws_rule & WS_BLANK_AT_EOL) {
162                 for (i = len - 1; i >= 0; i--) {
163                         if (isspace(line[i])) {
164                                 trailing_whitespace = i;
165                                 result |= WS_BLANK_AT_EOL;
166                         }
167                         else
168                                 break;
169                 }
170         }
171
172         if (trailing_whitespace == -1)
173                 trailing_whitespace = len;
174
175         /* Check indentation */
176         for (i = 0; i < trailing_whitespace; i++) {
177                 if (line[i] == ' ')
178                         continue;
179                 if (line[i] != '\t')
180                         break;
181                 if ((ws_rule & WS_SPACE_BEFORE_TAB) && written < i) {
182                         result |= WS_SPACE_BEFORE_TAB;
183                         if (stream) {
184                                 fputs(ws, stream);
185                                 fwrite(line + written, i - written, 1, stream);
186                                 fputs(reset, stream);
187                                 fwrite(line + i, 1, 1, stream);
188                         }
189                 } else if (ws_rule & WS_TAB_IN_INDENT) {
190                         result |= WS_TAB_IN_INDENT;
191                         if (stream) {
192                                 fwrite(line + written, i - written, 1, stream);
193                                 fputs(ws, stream);
194                                 fwrite(line + i, 1, 1, stream);
195                                 fputs(reset, stream);
196                         }
197                 } else if (stream) {
198                         fwrite(line + written, i - written + 1, 1, stream);
199                 }
200                 written = i + 1;
201         }
202
203         /* Check for indent using non-tab. */
204         if ((ws_rule & WS_INDENT_WITH_NON_TAB) && i - written >= ws_tab_width(ws_rule)) {
205                 result |= WS_INDENT_WITH_NON_TAB;
206                 if (stream) {
207                         fputs(ws, stream);
208                         fwrite(line + written, i - written, 1, stream);
209                         fputs(reset, stream);
210                 }
211                 written = i;
212         }
213
214         if (stream) {
215                 /*
216                  * Now the rest of the line starts at "written".
217                  * The non-highlighted part ends at "trailing_whitespace".
218                  */
219
220                 /* Emit non-highlighted (middle) segment. */
221                 if (trailing_whitespace - written > 0) {
222                         fputs(set, stream);
223                         fwrite(line + written,
224                             trailing_whitespace - written, 1, stream);
225                         fputs(reset, stream);
226                 }
227
228                 /* Highlight errors in trailing whitespace. */
229                 if (trailing_whitespace != len) {
230                         fputs(ws, stream);
231                         fwrite(line + trailing_whitespace,
232                             len - trailing_whitespace, 1, stream);
233                         fputs(reset, stream);
234                 }
235                 if (trailing_carriage_return)
236                         fputc('\r', stream);
237                 if (trailing_newline)
238                         fputc('\n', stream);
239         }
240         return result;
241 }
242
243 void ws_check_emit(const char *line, int len, unsigned ws_rule,
244                    FILE *stream, const char *set,
245                    const char *reset, const char *ws)
246 {
247         (void)ws_check_emit_1(line, len, ws_rule, stream, set, reset, ws);
248 }
249
250 unsigned ws_check(const char *line, int len, unsigned ws_rule)
251 {
252         return ws_check_emit_1(line, len, ws_rule, NULL, NULL, NULL, NULL);
253 }
254
255 int ws_blank_line(const char *line, int len, unsigned ws_rule)
256 {
257         /*
258          * We _might_ want to treat CR differently from other
259          * whitespace characters when ws_rule has WS_CR_AT_EOL, but
260          * for now we just use this stupid definition.
261          */
262         while (len-- > 0) {
263                 if (!isspace(*line))
264                         return 0;
265                 line++;
266         }
267         return 1;
268 }
269
270 /* Copy the line onto the end of the strbuf while fixing whitespaces */
271 void ws_fix_copy(struct strbuf *dst, const char *src, int len, unsigned ws_rule, int *error_count)
272 {
273         /*
274          * len is number of bytes to be copied from src, starting
275          * at src.  Typically src[len-1] is '\n', unless this is
276          * the incomplete last line.
277          */
278         int i;
279         int add_nl_to_tail = 0;
280         int add_cr_to_tail = 0;
281         int fixed = 0;
282         int last_tab_in_indent = -1;
283         int last_space_in_indent = -1;
284         int need_fix_leading_space = 0;
285
286         /*
287          * Strip trailing whitespace
288          */
289         if (ws_rule & WS_BLANK_AT_EOL) {
290                 if (0 < len && src[len - 1] == '\n') {
291                         add_nl_to_tail = 1;
292                         len--;
293                         if (0 < len && src[len - 1] == '\r') {
294                                 add_cr_to_tail = !!(ws_rule & WS_CR_AT_EOL);
295                                 len--;
296                         }
297                 }
298                 if (0 < len && isspace(src[len - 1])) {
299                         while (0 < len && isspace(src[len-1]))
300                                 len--;
301                         fixed = 1;
302                 }
303         }
304
305         /*
306          * Check leading whitespaces (indent)
307          */
308         for (i = 0; i < len; i++) {
309                 char ch = src[i];
310                 if (ch == '\t') {
311                         last_tab_in_indent = i;
312                         if ((ws_rule & WS_SPACE_BEFORE_TAB) &&
313                             0 <= last_space_in_indent)
314                             need_fix_leading_space = 1;
315                 } else if (ch == ' ') {
316                         last_space_in_indent = i;
317                         if ((ws_rule & WS_INDENT_WITH_NON_TAB) &&
318                             ws_tab_width(ws_rule) <= i - last_tab_in_indent)
319                                 need_fix_leading_space = 1;
320                 } else
321                         break;
322         }
323
324         if (need_fix_leading_space) {
325                 /* Process indent ourselves */
326                 int consecutive_spaces = 0;
327                 int last = last_tab_in_indent + 1;
328
329                 if (ws_rule & WS_INDENT_WITH_NON_TAB) {
330                         /* have "last" point at one past the indent */
331                         if (last_tab_in_indent < last_space_in_indent)
332                                 last = last_space_in_indent + 1;
333                         else
334                                 last = last_tab_in_indent + 1;
335                 }
336
337                 /*
338                  * between src[0..last-1], strip the funny spaces,
339                  * updating them to tab as needed.
340                  */
341                 for (i = 0; i < last; i++) {
342                         char ch = src[i];
343                         if (ch != ' ') {
344                                 consecutive_spaces = 0;
345                                 strbuf_addch(dst, ch);
346                         } else {
347                                 consecutive_spaces++;
348                                 if (consecutive_spaces == ws_tab_width(ws_rule)) {
349                                         strbuf_addch(dst, '\t');
350                                         consecutive_spaces = 0;
351                                 }
352                         }
353                 }
354                 while (0 < consecutive_spaces--)
355                         strbuf_addch(dst, ' ');
356                 len -= last;
357                 src += last;
358                 fixed = 1;
359         } else if ((ws_rule & WS_TAB_IN_INDENT) && last_tab_in_indent >= 0) {
360                 /* Expand tabs into spaces */
361                 int start = dst->len;
362                 int last = last_tab_in_indent + 1;
363                 for (i = 0; i < last; i++) {
364                         if (src[i] == '\t')
365                                 do {
366                                         strbuf_addch(dst, ' ');
367                                 } while ((dst->len - start) % ws_tab_width(ws_rule));
368                         else
369                                 strbuf_addch(dst, src[i]);
370                 }
371                 len -= last;
372                 src += last;
373                 fixed = 1;
374         }
375
376         strbuf_add(dst, src, len);
377         if (add_cr_to_tail)
378                 strbuf_addch(dst, '\r');
379         if (add_nl_to_tail)
380                 strbuf_addch(dst, '\n');
381         if (fixed && error_count)
382                 (*error_count)++;
383 }