about summary refs log tree commit diff
path: root/third_party/git/xdiff-interface.c
blob: 8509f9ea223a1282a367874c3e3a3ef0c351a30f (plain) (blame)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
#include "cache.h"
#include "config.h"
#include "object-store.h"
#include "xdiff-interface.h"
#include "xdiff/xtypes.h"
#include "xdiff/xdiffi.h"
#include "xdiff/xemit.h"
#include "xdiff/xmacros.h"
#include "xdiff/xutils.h"

struct xdiff_emit_state {
	xdiff_emit_hunk_fn hunk_fn;
	xdiff_emit_line_fn line_fn;
	void *consume_callback_data;
	struct strbuf remainder;
};

static int xdiff_out_hunk(void *priv_,
			  long old_begin, long old_nr,
			  long new_begin, long new_nr,
			  const char *func, long funclen)
{
	struct xdiff_emit_state *priv = priv_;

	if (priv->remainder.len)
		BUG("xdiff emitted hunk in the middle of a line");

	priv->hunk_fn(priv->consume_callback_data,
		      old_begin, old_nr, new_begin, new_nr,
		      func, funclen);
	return 0;
}

static void consume_one(void *priv_, char *s, unsigned long size)
{
	struct xdiff_emit_state *priv = priv_;
	char *ep;
	while (size) {
		unsigned long this_size;
		ep = memchr(s, '\n', size);
		this_size = (ep == NULL) ? size : (ep - s + 1);
		priv->line_fn(priv->consume_callback_data, s, this_size);
		size -= this_size;
		s += this_size;
	}
}

static int xdiff_outf(void *priv_, mmbuffer_t *mb, int nbuf)
{
	struct xdiff_emit_state *priv = priv_;
	int i;

	if (!priv->line_fn)
		return 0;

	for (i = 0; i < nbuf; i++) {
		if (mb[i].ptr[mb[i].size-1] != '\n') {
			/* Incomplete line */
			strbuf_add(&priv->remainder, mb[i].ptr, mb[i].size);
			continue;
		}

		/* we have a complete line */
		if (!priv->remainder.len) {
			consume_one(priv, mb[i].ptr, mb[i].size);
			continue;
		}
		strbuf_add(&priv->remainder, mb[i].ptr, mb[i].size);
		consume_one(priv, priv->remainder.buf, priv->remainder.len);
		strbuf_reset(&priv->remainder);
	}
	if (priv->remainder.len) {
		consume_one(priv, priv->remainder.buf, priv->remainder.len);
		strbuf_reset(&priv->remainder);
	}
	return 0;
}

/*
 * Trim down common substring at the end of the buffers,
 * but end on a complete line.
 */
static void trim_common_tail(mmfile_t *a, mmfile_t *b)
{
	const int blk = 1024;
	long trimmed = 0, recovered = 0;
	char *ap = a->ptr + a->size;
	char *bp = b->ptr + b->size;
	long smaller = (a->size < b->size) ? a->size : b->size;

	while (blk + trimmed <= smaller && !memcmp(ap - blk, bp - blk, blk)) {
		trimmed += blk;
		ap -= blk;
		bp -= blk;
	}

	while (recovered < trimmed)
		if (ap[recovered++] == '\n')
			break;
	a->size -= trimmed - recovered;
	b->size -= trimmed - recovered;
}

int xdi_diff(mmfile_t *mf1, mmfile_t *mf2, xpparam_t const *xpp, xdemitconf_t const *xecfg, xdemitcb_t *xecb)
{
	mmfile_t a = *mf1;
	mmfile_t b = *mf2;

	if (mf1->size > MAX_XDIFF_SIZE || mf2->size > MAX_XDIFF_SIZE)
		return -1;

	if (!xecfg->ctxlen && !(xecfg->flags & XDL_EMIT_FUNCCONTEXT))
		trim_common_tail(&a, &b);

	return xdl_diff(&a, &b, xpp, xecfg, xecb);
}

void discard_hunk_line(void *priv,
		       long ob, long on, long nb, long nn,
		       const char *func, long funclen)
{
}

int xdi_diff_outf(mmfile_t *mf1, mmfile_t *mf2,
		  xdiff_emit_hunk_fn hunk_fn,
		  xdiff_emit_line_fn line_fn,
		  void *consume_callback_data,
		  xpparam_t const *xpp, xdemitconf_t const *xecfg)
{
	int ret;
	struct xdiff_emit_state state;
	xdemitcb_t ecb;

	memset(&state, 0, sizeof(state));
	state.hunk_fn = hunk_fn;
	state.line_fn = line_fn;
	state.consume_callback_data = consume_callback_data;
	memset(&ecb, 0, sizeof(ecb));
	if (hunk_fn)
		ecb.out_hunk = xdiff_out_hunk;
	ecb.out_line = xdiff_outf;
	ecb.priv = &state;
	strbuf_init(&state.remainder, 0);
	ret = xdi_diff(mf1, mf2, xpp, xecfg, &ecb);
	strbuf_release(&state.remainder);
	return ret;
}

int read_mmfile(mmfile_t *ptr, const char *filename)
{
	struct stat st;
	FILE *f;
	size_t sz;

	if (stat(filename, &st))
		return error_errno("Could not stat %s", filename);
	if ((f = fopen(filename, "rb")) == NULL)
		return error_errno("Could not open %s", filename);
	sz = xsize_t(st.st_size);
	ptr->ptr = xmalloc(sz ? sz : 1);
	if (sz && fread(ptr->ptr, sz, 1, f) != 1) {
		fclose(f);
		return error("Could not read %s", filename);
	}
	fclose(f);
	ptr->size = sz;
	return 0;
}

void read_mmblob(mmfile_t *ptr, const struct object_id *oid)
{
	unsigned long size;
	enum object_type type;

	if (oideq(oid, &null_oid)) {
		ptr->ptr = xstrdup("");
		ptr->size = 0;
		return;
	}

	ptr->ptr = read_object_file(oid, &type, &size);
	if (!ptr->ptr || type != OBJ_BLOB)
		die("unable to read blob object %s", oid_to_hex(oid));
	ptr->size = size;
}

#define FIRST_FEW_BYTES 8000
int buffer_is_binary(const char *ptr, unsigned long size)
{
	if (FIRST_FEW_BYTES < size)
		size = FIRST_FEW_BYTES;
	return !!memchr(ptr, 0, size);
}

struct ff_regs {
	int nr;
	struct ff_reg {
		regex_t re;
		int negate;
	} *array;
};

static long ff_regexp(const char *line, long len,
		char *buffer, long buffer_size, void *priv)
{
	struct ff_regs *regs = priv;
	regmatch_t pmatch[2];
	int i;
	int result;

	/* Exclude terminating newline (and cr) from matching */
	if (len > 0 && line[len-1] == '\n') {
		if (len > 1 && line[len-2] == '\r')
			len -= 2;
		else
			len--;
	}

	for (i = 0; i < regs->nr; i++) {
		struct ff_reg *reg = regs->array + i;
		if (!regexec_buf(&reg->re, line, len, 2, pmatch, 0)) {
			if (reg->negate)
				return -1;
			break;
		}
	}
	if (regs->nr <= i)
		return -1;
	i = pmatch[1].rm_so >= 0 ? 1 : 0;
	line += pmatch[i].rm_so;
	result = pmatch[i].rm_eo - pmatch[i].rm_so;
	if (result > buffer_size)
		result = buffer_size;
	while (result > 0 && (isspace(line[result - 1])))
		result--;
	memcpy(buffer, line, result);
	return result;
}

void xdiff_set_find_func(xdemitconf_t *xecfg, const char *value, int cflags)
{
	int i;
	struct ff_regs *regs;

	xecfg->find_func = ff_regexp;
	regs = xecfg->find_func_priv = xmalloc(sizeof(struct ff_regs));
	for (i = 0, regs->nr = 1; value[i]; i++)
		if (value[i] == '\n')
			regs->nr++;
	ALLOC_ARRAY(regs->array, regs->nr);
	for (i = 0; i < regs->nr; i++) {
		struct ff_reg *reg = regs->array + i;
		const char *ep = strchr(value, '\n'), *expression;
		char *buffer = NULL;

		reg->negate = (*value == '!');
		if (reg->negate && i == regs->nr - 1)
			die("Last expression must not be negated: %s", value);
		if (*value == '!')
			value++;
		if (ep)
			expression = buffer = xstrndup(value, ep - value);
		else
			expression = value;
		if (regcomp(&reg->re, expression, cflags))
			die("Invalid regexp to look for hunk header: %s", expression);
		free(buffer);
		value = ep + 1;
	}
}

void xdiff_clear_find_func(xdemitconf_t *xecfg)
{
	if (xecfg->find_func) {
		int i;
		struct ff_regs *regs = xecfg->find_func_priv;

		for (i = 0; i < regs->nr; i++)
			regfree(&regs->array[i].re);
		free(regs->array);
		free(regs);
		xecfg->find_func = NULL;
		xecfg->find_func_priv = NULL;
	}
}

unsigned long xdiff_hash_string(const char *s, size_t len, long flags)
{
	return xdl_hash_record(&s, s + len, flags);
}

int xdiff_compare_lines(const char *l1, long s1,
			const char *l2, long s2, long flags)
{
	return xdl_recmatch(l1, s1, l2, s2, flags);
}

int git_xmerge_style = -1;

int git_xmerge_config(const char *var, const char *value, void *cb)
{
	if (!strcmp(var, "merge.conflictstyle")) {
		if (!value)
			die("'%s' is not a boolean", var);
		if (!strcmp(value, "diff3"))
			git_xmerge_style = XDL_MERGE_DIFF3;
		else if (!strcmp(value, "merge"))
			git_xmerge_style = 0;
		/*
		 * Please update _git_checkout() in
		 * git-completion.bash when you add new merge config
		 */
		else
			die("unknown style '%s' given for '%s'",
			    value, var);
		return 0;
	}
	return git_default_config(var, value, cb);
}