merge_driver.c 10.1 KB
Newer Older
1 2 3 4 5 6 7
/*
 * Copyright (C) the libgit2 contributors. All rights reserved.
 *
 * This file is part of libgit2, distributed under the GNU GPL v2 with
 * a Linking Exception. For full terms see the included COPYING file.
 */

8 9
#include "merge_driver.h"

10
#include "vector.h"
11
#include "runtime.h"
12 13 14 15 16 17 18 19 20
#include "merge.h"
#include "git2/merge.h"
#include "git2/sys/merge.h"

static const char *merge_driver_name__text = "text";
static const char *merge_driver_name__union = "union";
static const char *merge_driver_name__binary = "binary";

struct merge_driver_registry {
21
	git_rwlock lock;
22 23 24 25 26 27 28 29 30
	git_vector drivers;
};

typedef struct {
	git_merge_driver *driver;
	int initialized;
	char name[GIT_FLEX_ARRAY];
} git_merge_driver_entry;

31
static struct merge_driver_registry merge_driver_registry;
32

33 34
static void git_merge_driver_global_shutdown(void);

35 36
git_repository *git_merge_driver_source_repo(
	const git_merge_driver_source *src)
37
{
38
	GIT_ASSERT_ARG_WITH_RETVAL(src, NULL);
39 40 41
	return src->repo;
}

42 43
const git_index_entry *git_merge_driver_source_ancestor(
	const git_merge_driver_source *src)
44
{
45
	GIT_ASSERT_ARG_WITH_RETVAL(src, NULL);
46 47 48
	return src->ancestor;
}

49 50
const git_index_entry *git_merge_driver_source_ours(
	const git_merge_driver_source *src)
51
{
52
	GIT_ASSERT_ARG_WITH_RETVAL(src, NULL);
53 54 55
	return src->ours;
}

56 57
const git_index_entry *git_merge_driver_source_theirs(
	const git_merge_driver_source *src)
58
{
59
	GIT_ASSERT_ARG_WITH_RETVAL(src, NULL);
60 61 62
	return src->theirs;
}

63 64
const git_merge_file_options *git_merge_driver_source_file_options(
	const git_merge_driver_source *src)
65
{
66
	GIT_ASSERT_ARG_WITH_RETVAL(src, NULL);
67 68
	return src->file_opts;
}
69

70
int git_merge_driver__builtin_apply(
71 72 73 74
	git_merge_driver *self,
	const char **path_out,
	uint32_t *mode_out,
	git_buf *merged_out,
75
	const char *filter_name,
76 77
	const git_merge_driver_source *src)
{
78
	git_merge_driver__builtin *driver = (git_merge_driver__builtin *)self;
79 80 81 82
	git_merge_file_options file_opts = GIT_MERGE_FILE_OPTIONS_INIT;
	git_merge_file_result result = {0};
	int error;

83
	GIT_UNUSED(filter_name);
84 85 86 87

	if (src->file_opts)
		memcpy(&file_opts, src->file_opts, sizeof(git_merge_file_options));

88 89
	if (driver->favor)
		file_opts.favor = driver->favor;
90 91 92 93 94 95

	if ((error = git_merge_file_from_index(&result, src->repo,
		src->ancestor, src->ours, src->theirs, &file_opts)) < 0)
		goto done;

	if (!result.automergeable &&
96
		!(file_opts.flags & GIT_MERGE_FILE_ACCEPT_CONFLICTS)) {
97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112
		error = GIT_EMERGECONFLICT;
		goto done;
	}

	*path_out = git_merge_file__best_path(
		src->ancestor ? src->ancestor->path : NULL,
		src->ours ? src->ours->path : NULL,
		src->theirs ? src->theirs->path : NULL);

	*mode_out = git_merge_file__best_mode(
		src->ancestor ? src->ancestor->mode : 0,
		src->ours ? src->ours->mode : 0,
		src->theirs ? src->theirs->mode : 0);

	merged_out->ptr = (char *)result.ptr;
	merged_out->size = result.len;
113
	merged_out->reserved = 0;
114 115 116 117 118 119 120 121 122 123 124 125
	result.ptr = NULL;

done:
	git_merge_file_result_free(&result);
	return error;
}

static int merge_driver_binary_apply(
	git_merge_driver *self,
	const char **path_out,
	uint32_t *mode_out,
	git_buf *merged_out,
126
	const char *filter_name,
127 128 129 130 131 132
	const git_merge_driver_source *src)
{
	GIT_UNUSED(self);
	GIT_UNUSED(path_out);
	GIT_UNUSED(mode_out);
	GIT_UNUSED(merged_out);
133
	GIT_UNUSED(filter_name);
134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154
	GIT_UNUSED(src);

	return GIT_EMERGECONFLICT;
}

static int merge_driver_entry_cmp(const void *a, const void *b)
{
	const git_merge_driver_entry *entry_a = a;
	const git_merge_driver_entry *entry_b = b;

	return strcmp(entry_a->name, entry_b->name);
}

static int merge_driver_entry_search(const void *a, const void *b)
{
	const char *name_a = a;
	const git_merge_driver_entry *entry_b = b;

	return strcmp(name_a, entry_b->name);
}

155 156 157 158 159 160 161 162
git_merge_driver__builtin git_merge_driver__text = {
	{
		GIT_MERGE_DRIVER_VERSION,
		NULL,
		NULL,
		git_merge_driver__builtin_apply,
	},
	GIT_MERGE_FILE_FAVOR_NORMAL
163 164
};

165 166 167 168 169 170 171 172
git_merge_driver__builtin git_merge_driver__union = {
	{
		GIT_MERGE_DRIVER_VERSION,
		NULL,
		NULL,
		git_merge_driver__builtin_apply,
	},
	GIT_MERGE_FILE_FAVOR_UNION
173 174 175 176 177 178 179 180 181
};

git_merge_driver git_merge_driver__binary = {
	GIT_MERGE_DRIVER_VERSION,
	NULL,
	NULL,
	merge_driver_binary_apply
};

182 183 184
/* Note: callers must lock the registry before calling this function */
static int merge_driver_registry_insert(
	const char *name, git_merge_driver *driver)
185
{
186
	git_merge_driver_entry *entry;
187

188
	entry = git__calloc(1, sizeof(git_merge_driver_entry) + strlen(name) + 1);
189
	GIT_ERROR_CHECK_ALLOC(entry);
190

191 192
	strcpy(entry->name, name);
	entry->driver = driver;
193

194 195 196
	return git_vector_insert_sorted(
		&merge_driver_registry.drivers, entry, NULL);
}
197

198 199 200
int git_merge_driver_global_init(void)
{
	int error;
201

202 203
	if (git_rwlock_init(&merge_driver_registry.lock) < 0)
		return -1;
204

205 206 207 208 209
	if ((error = git_vector_init(&merge_driver_registry.drivers, 3,
		merge_driver_entry_cmp)) < 0)
		goto done;

	if ((error = merge_driver_registry_insert(
210
			merge_driver_name__text, &git_merge_driver__text.base)) < 0 ||
211
		(error = merge_driver_registry_insert(
212
			merge_driver_name__union, &git_merge_driver__union.base)) < 0 ||
213
		(error = merge_driver_registry_insert(
214
			merge_driver_name__binary, &git_merge_driver__binary)) < 0)
215
		goto done;
216

217
	error = git_runtime_shutdown_register(git_merge_driver_global_shutdown);
218 219 220

done:
	if (error < 0)
221
		git_vector_free_deep(&merge_driver_registry.drivers);
222 223 224 225

	return error;
}

226
static void git_merge_driver_global_shutdown(void)
227 228
{
	git_merge_driver_entry *entry;
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
	size_t i;

	if (git_rwlock_wrlock(&merge_driver_registry.lock) < 0)
		return;

	git_vector_foreach(&merge_driver_registry.drivers, i, entry) {
		if (entry->driver->shutdown)
			entry->driver->shutdown(entry->driver);

		git__free(entry);
	}

	git_vector_free(&merge_driver_registry.drivers);

	git_rwlock_wrunlock(&merge_driver_registry.lock);
	git_rwlock_free(&merge_driver_registry.lock);
}

/* Note: callers must lock the registry before calling this function */
static int merge_driver_registry_find(size_t *pos, const char *name)
{
	return git_vector_search2(pos, &merge_driver_registry.drivers,
		merge_driver_entry_search, name);
}

/* Note: callers must lock the registry before calling this function */
static git_merge_driver_entry *merge_driver_registry_lookup(
	size_t *pos, const char *name)
{
	git_merge_driver_entry *entry = NULL;

	if (!merge_driver_registry_find(pos, name))
		entry = git_vector_get(&merge_driver_registry.drivers, *pos);

	return entry;
}

int git_merge_driver_register(const char *name, git_merge_driver *driver)
{
	int error;
269

270 271
	GIT_ASSERT_ARG(name);
	GIT_ASSERT_ARG(driver);
272

273
	if (git_rwlock_wrlock(&merge_driver_registry.lock) < 0) {
274
		git_error_set(GIT_ERROR_OS, "failed to lock merge driver registry");
275
		return -1;
276
	}
277

278
	if (!merge_driver_registry_find(NULL, name)) {
279
		git_error_set(GIT_ERROR_MERGE, "attempt to reregister existing driver '%s'",
280 281 282 283
			name);
		error = GIT_EEXISTS;
		goto done;
	}
284

285
	error = merge_driver_registry_insert(name, driver);
286

287 288 289
done:
	git_rwlock_wrunlock(&merge_driver_registry.lock);
	return error;
290 291 292 293 294 295
}

int git_merge_driver_unregister(const char *name)
{
	git_merge_driver_entry *entry;
	size_t pos;
296 297 298
	int error = 0;

	if (git_rwlock_wrlock(&merge_driver_registry.lock) < 0) {
299
		git_error_set(GIT_ERROR_OS, "failed to lock merge driver registry");
300 301
		return -1;
	}
302

303
	if ((entry = merge_driver_registry_lookup(&pos, name)) == NULL) {
304
		git_error_set(GIT_ERROR_MERGE, "cannot find merge driver '%s' to unregister",
305 306 307 308
			name);
		error = GIT_ENOTFOUND;
		goto done;
	}
309

310
	git_vector_remove(&merge_driver_registry.drivers, pos);
311 312 313 314 315 316 317 318

	if (entry->initialized && entry->driver->shutdown) {
		entry->driver->shutdown(entry->driver);
		entry->initialized = false;
	}

	git__free(entry);

319 320 321
done:
	git_rwlock_wrunlock(&merge_driver_registry.lock);
	return error;
322 323 324 325 326 327 328 329 330 331
}

git_merge_driver *git_merge_driver_lookup(const char *name)
{
	git_merge_driver_entry *entry;
	size_t pos;
	int error;

	/* If we've decided the merge driver to use internally - and not
	 * based on user configuration (in merge_driver_name_for_path)
332 333
	 * then we can use a hardcoded name to compare instead of bothering
	 * to take a lock and look it up in the vector.
334 335
	 */
	if (name == merge_driver_name__text)
336
		return &git_merge_driver__text.base;
337 338 339
	else if (name == merge_driver_name__binary)
		return &git_merge_driver__binary;

340
	if (git_rwlock_rdlock(&merge_driver_registry.lock) < 0) {
341
		git_error_set(GIT_ERROR_OS, "failed to lock merge driver registry");
342
		return NULL;
343
	}
344

345
	entry = merge_driver_registry_lookup(&pos, name);
346

347
	git_rwlock_rdunlock(&merge_driver_registry.lock);
348

349
	if (entry == NULL) {
350
		git_error_set(GIT_ERROR_MERGE, "cannot use an unregistered filter");
351 352
		return NULL;
	}
353 354 355 356 357 358 359 360 361

	if (!entry->initialized) {
		if (entry->driver->initialize &&
			(error = entry->driver->initialize(entry->driver)) < 0)
			return NULL;

		entry->initialized = 1;
	}

362
	return entry->driver;
363 364 365 366 367
}

static int merge_driver_name_for_path(
	const char **out,
	git_repository *repo,
368 369
	const char *path,
	const char *default_driver)
370 371 372 373 374 375 376 377 378 379
{
	const char *value;
	int error;

	*out = NULL;

	if ((error = git_attr_get(&value, repo, 0, path, "merge")) < 0)
		return error;

	/* set: use the built-in 3-way merge driver ("text") */
380
	if (GIT_ATTR_IS_TRUE(value))
381 382 383
		*out = merge_driver_name__text;

	/* unset: do not merge ("binary") */
384
	else if (GIT_ATTR_IS_FALSE(value))
385 386
		*out = merge_driver_name__binary;

387
	else if (GIT_ATTR_IS_UNSPECIFIED(value) && default_driver)
388 389
		*out = default_driver;

390
	else if (GIT_ATTR_IS_UNSPECIFIED(value))
391
		*out = merge_driver_name__text;
392 393 394 395

	else
		*out = value;

396 397 398
	return 0;
}

399 400 401 402 403 404 405 406 407 408 409 410

GIT_INLINE(git_merge_driver *) merge_driver_lookup_with_wildcard(
	const char *name)
{
	git_merge_driver *driver = git_merge_driver_lookup(name);

	if (driver == NULL)
		driver = git_merge_driver_lookup("*");

	return driver;
}

411
int git_merge_driver_for_source(
412
	const char **name_out,
413 414 415 416 417 418 419 420 421 422 423
	git_merge_driver **driver_out,
	const git_merge_driver_source *src)
{
	const char *path, *driver_name;
	int error = 0;

	path = git_merge_file__best_path(
		src->ancestor ? src->ancestor->path : NULL,
		src->ours ? src->ours->path : NULL,
		src->theirs ? src->theirs->path : NULL);

424 425
	if ((error = merge_driver_name_for_path(
			&driver_name, src->repo, path, src->default_driver)) < 0)
426 427
		return error;

428 429
	*name_out = driver_name;
	*driver_out = merge_driver_lookup_with_wildcard(driver_name);
430 431 432
	return error;
}