about summary refs log tree commit diff
path: root/third_party/git/fsmonitor.c
blob: 231e83a94db58e4efb2f4d7a1dbe90220bd2f317 (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
#include "cache.h"
#include "config.h"
#include "dir.h"
#include "ewah/ewok.h"
#include "fsmonitor.h"
#include "run-command.h"
#include "strbuf.h"

#define INDEX_EXTENSION_VERSION	(1)
#define HOOK_INTERFACE_VERSION	(1)

struct trace_key trace_fsmonitor = TRACE_KEY_INIT(FSMONITOR);

static void fsmonitor_ewah_callback(size_t pos, void *is)
{
	struct index_state *istate = (struct index_state *)is;
	struct cache_entry *ce = istate->cache[pos];

	ce->ce_flags &= ~CE_FSMONITOR_VALID;
}

int read_fsmonitor_extension(struct index_state *istate, const void *data,
	unsigned long sz)
{
	const char *index = data;
	uint32_t hdr_version;
	uint32_t ewah_size;
	struct ewah_bitmap *fsmonitor_dirty;
	int ret;

	if (sz < sizeof(uint32_t) + sizeof(uint64_t) + sizeof(uint32_t))
		return error("corrupt fsmonitor extension (too short)");

	hdr_version = get_be32(index);
	index += sizeof(uint32_t);
	if (hdr_version != INDEX_EXTENSION_VERSION)
		return error("bad fsmonitor version %d", hdr_version);

	istate->fsmonitor_last_update = get_be64(index);
	index += sizeof(uint64_t);

	ewah_size = get_be32(index);
	index += sizeof(uint32_t);

	fsmonitor_dirty = ewah_new();
	ret = ewah_read_mmap(fsmonitor_dirty, index, ewah_size);
	if (ret != ewah_size) {
		ewah_free(fsmonitor_dirty);
		return error("failed to parse ewah bitmap reading fsmonitor index extension");
	}
	istate->fsmonitor_dirty = fsmonitor_dirty;

	trace_printf_key(&trace_fsmonitor, "read fsmonitor extension successful");
	return 0;
}

void fill_fsmonitor_bitmap(struct index_state *istate)
{
	unsigned int i;
	istate->fsmonitor_dirty = ewah_new();
	for (i = 0; i < istate->cache_nr; i++)
		if (!(istate->cache[i]->ce_flags & CE_FSMONITOR_VALID))
			ewah_set(istate->fsmonitor_dirty, i);
}

void write_fsmonitor_extension(struct strbuf *sb, struct index_state *istate)
{
	uint32_t hdr_version;
	uint64_t tm;
	uint32_t ewah_start;
	uint32_t ewah_size = 0;
	int fixup = 0;

	put_be32(&hdr_version, INDEX_EXTENSION_VERSION);
	strbuf_add(sb, &hdr_version, sizeof(uint32_t));

	put_be64(&tm, istate->fsmonitor_last_update);
	strbuf_add(sb, &tm, sizeof(uint64_t));
	fixup = sb->len;
	strbuf_add(sb, &ewah_size, sizeof(uint32_t)); /* we'll fix this up later */

	ewah_start = sb->len;
	ewah_serialize_strbuf(istate->fsmonitor_dirty, sb);
	ewah_free(istate->fsmonitor_dirty);
	istate->fsmonitor_dirty = NULL;

	/* fix up size field */
	put_be32(&ewah_size, sb->len - ewah_start);
	memcpy(sb->buf + fixup, &ewah_size, sizeof(uint32_t));

	trace_printf_key(&trace_fsmonitor, "write fsmonitor extension successful");
}

/*
 * Call the query-fsmonitor hook passing the time of the last saved results.
 */
static int query_fsmonitor(int version, uint64_t last_update, struct strbuf *query_result)
{
	struct child_process cp = CHILD_PROCESS_INIT;

	if (!core_fsmonitor)
		return -1;

	argv_array_push(&cp.args, core_fsmonitor);
	argv_array_pushf(&cp.args, "%d", version);
	argv_array_pushf(&cp.args, "%" PRIuMAX, (uintmax_t)last_update);
	cp.use_shell = 1;
	cp.dir = get_git_work_tree();

	return capture_command(&cp, query_result, 1024);
}

static void fsmonitor_refresh_callback(struct index_state *istate, const char *name)
{
	int pos = index_name_pos(istate, name, strlen(name));

	if (pos >= 0) {
		struct cache_entry *ce = istate->cache[pos];
		ce->ce_flags &= ~CE_FSMONITOR_VALID;
	}

	/*
	 * Mark the untracked cache dirty even if it wasn't found in the index
	 * as it could be a new untracked file.
	 */
	trace_printf_key(&trace_fsmonitor, "fsmonitor_refresh_callback '%s'", name);
	untracked_cache_invalidate_path(istate, name, 0);
}

void refresh_fsmonitor(struct index_state *istate)
{
	struct strbuf query_result = STRBUF_INIT;
	int query_success = 0;
	size_t bol; /* beginning of line */
	uint64_t last_update;
	char *buf;
	unsigned int i;

	if (!core_fsmonitor || istate->fsmonitor_has_run_once)
		return;
	istate->fsmonitor_has_run_once = 1;

	trace_printf_key(&trace_fsmonitor, "refresh fsmonitor");
	/*
	 * This could be racy so save the date/time now and query_fsmonitor
	 * should be inclusive to ensure we don't miss potential changes.
	 */
	last_update = getnanotime();

	/*
	 * If we have a last update time, call query_fsmonitor for the set of
	 * changes since that time, else assume everything is possibly dirty
	 * and check it all.
	 */
	if (istate->fsmonitor_last_update) {
		query_success = !query_fsmonitor(HOOK_INTERFACE_VERSION,
			istate->fsmonitor_last_update, &query_result);
		trace_performance_since(last_update, "fsmonitor process '%s'", core_fsmonitor);
		trace_printf_key(&trace_fsmonitor, "fsmonitor process '%s' returned %s",
			core_fsmonitor, query_success ? "success" : "failure");
	}

	/* a fsmonitor process can return '/' to indicate all entries are invalid */
	if (query_success && query_result.buf[0] != '/') {
		/* Mark all entries returned by the monitor as dirty */
		buf = query_result.buf;
		bol = 0;
		for (i = 0; i < query_result.len; i++) {
			if (buf[i] != '\0')
				continue;
			fsmonitor_refresh_callback(istate, buf + bol);
			bol = i + 1;
		}
		if (bol < query_result.len)
			fsmonitor_refresh_callback(istate, buf + bol);
	} else {
		/* Mark all entries invalid */
		for (i = 0; i < istate->cache_nr; i++)
			istate->cache[i]->ce_flags &= ~CE_FSMONITOR_VALID;

		/* If we're going to check every file, ensure we save the results */
		istate->cache_changed |= FSMONITOR_CHANGED;

		if (istate->untracked)
			istate->untracked->use_fsmonitor = 0;
	}
	strbuf_release(&query_result);

	/* Now that we've updated istate, save the last_update time */
	istate->fsmonitor_last_update = last_update;
}

void add_fsmonitor(struct index_state *istate)
{
	unsigned int i;

	if (!istate->fsmonitor_last_update) {
		trace_printf_key(&trace_fsmonitor, "add fsmonitor");
		istate->cache_changed |= FSMONITOR_CHANGED;
		istate->fsmonitor_last_update = getnanotime();

		/* reset the fsmonitor state */
		for (i = 0; i < istate->cache_nr; i++)
			istate->cache[i]->ce_flags &= ~CE_FSMONITOR_VALID;

		/* reset the untracked cache */
		if (istate->untracked) {
			add_untracked_cache(istate);
			istate->untracked->use_fsmonitor = 1;
		}

		/* Update the fsmonitor state */
		refresh_fsmonitor(istate);
	}
}

void remove_fsmonitor(struct index_state *istate)
{
	if (istate->fsmonitor_last_update) {
		trace_printf_key(&trace_fsmonitor, "remove fsmonitor");
		istate->cache_changed |= FSMONITOR_CHANGED;
		istate->fsmonitor_last_update = 0;
	}
}

void tweak_fsmonitor(struct index_state *istate)
{
	unsigned int i;
	int fsmonitor_enabled = git_config_get_fsmonitor();

	if (istate->fsmonitor_dirty) {
		if (fsmonitor_enabled) {
			/* Mark all entries valid */
			for (i = 0; i < istate->cache_nr; i++) {
				istate->cache[i]->ce_flags |= CE_FSMONITOR_VALID;
			}

			/* Mark all previously saved entries as dirty */
			ewah_each_bit(istate->fsmonitor_dirty, fsmonitor_ewah_callback, istate);

			/* Now mark the untracked cache for fsmonitor usage */
			if (istate->untracked)
				istate->untracked->use_fsmonitor = 1;
		}

		ewah_free(istate->fsmonitor_dirty);
		istate->fsmonitor_dirty = NULL;
	}

	switch (fsmonitor_enabled) {
	case -1: /* keep: do nothing */
		break;
	case 0: /* false */
		remove_fsmonitor(istate);
		break;
	case 1: /* true */
		add_fsmonitor(istate);
		break;
	default: /* unknown value: do nothing */
		break;
	}
}